Genetic Lineage Tracing of Biliary Epithelial Cells

Lineage tracing of liver cells is a powerful tool to understand liver embryonic development, healthy liver cell homeostasis, tissue repair, and regeneration. Lineage tracing of biliary epithelial cells (BECs) in the adult liver has been used to assess the contribution of the biliary epithelium to liver injury, regeneration, and disease. These studies have shown the contribution of BECs to the expansion of ductular reaction (DR) and liver progenitor cells (LPCs) and eventually the generation of new hepatocytes. Few genetic lineage-tracing mouse models have been proved to trace BECs. This chapter is focused on lineage tracing of BECs in mouse models of liver injury and regeneration. First, we mention different existing approaches to trace the biliary epithelium based on proteins specifically expressed by BECs such as sex-determining region Y-box 9 (SOX9), osteopontin (OPN), and cytokeratin-19 (KRT19). Second, we describe mouse models that can be used to evaluate cell fate during liver injury and regeneration (i.e., partial hepatectomy (PHx), acute liver injury models, and chronic liver damage models such as 3,5-diethoxycarbonyl-1,4-dihydro-collidin (DDC) diet, choline-deficient ethionine-supplemented (CDE) diet, or chronic carbon tetrachloride (CCl₄) administration). Third, we suggest possible readouts to assess BECs fate based on immunofluorescence analysis.