Characterization of CD63+ adult liver stem cells and downstream lineages

Understanding the liver stem cells (LSCs) holds great promise for new insights into liver diseases and liver regeneration. By employing single-cell RNA-seq technology, we examined transcriptome features of distinct Krt19 lineage-tracing cell types isolated from Krt19CreERT; Rosa26R-GFP reporter mouse livers, and identified adult LSCs, as well as their downstream hepatocytes and cholangiocytes. Importantly, we discovered a novel cell surface LSCs marker, CD63, as well as CD56, which distinguished active and quiescent LSCs. Furthermore, we confirmed that CD63+CD56- quiescent LSCs could be activated by a combined action of VEGF and bFGF, and subsequently underwent terminal differentiation. These findings define an authentic adult liver stem cells compartment and highlight its contribution to liver homeostasis during pathophysiologic processes. Liver cells of the Krt19CreERT;Rosa26R-GFP or CD63CreERT2;Rosa26-TdTomato mice were isolated by Fluorescence-activated cell sorting (FACS) according to the presence of GFP or Tomato(Cherry) signal and analyzed using scRNAseq.