In vivo CRISPR screen reveals interplay of epigenetic regulators underlies kinetics of hepatobiliary reprogramming [CUT&Tag]

Under chronic liver injury, a small fraction of hepatocytes undergoes reprogramming to biliary epithelial cells (BECs) through a multistep process of chromatin and transcriptional remodeling in which the hepatocyte phenotype is repressed and the biliary phenotype is activated. However, the epigenetic basis underlying this phenomenon is largely unknown. Here, using a lineage-traced model of cholestatic liver injury, we investigated the role of histone posttranslational modification in the kinetics of biliary reprogramming. In this study, we performed CUT&Tag to profile the changes in histone landscape throughout reprogramming and explored the impact of Nsd1 and Kdm2a knockout. Mice were challenged with DDC for 8 weeks, then reprogrammed cells and biliary cells were harvested. After DDC-induced cholestatic injury, GFP+CD24-EPCAM- cells (DDC-injured hepatocytes/early reprogrammed cells), GFP+CD24+EPCAM- cells (intermediate reprogrammed cells) and GFP+CD24+EPCAM+ cells (late reprogrammed cells) were isolated, along with noninjured hepatocytes and BECs from Kdm2a-KO, Nsd1-KO, or empty vector (EV) control mice.