Extensive conversion of hepatic biliary epithelial cells to hepatocytes after near total loss of hepatocytes in zebrafish

TY Choi, N Ninov, DYR Stainier, D Shin - Gastroenterology, 2014 - Elsevier
Gastroenterology, 2014Elsevier
Background & Aims Biliary epithelial cells (BECs) are considered to be a source of
regenerating hepatocytes when hepatocyte proliferation is compromised. However, there is
still controversy about the extent to which BECs can contribute to the regenerating
hepatocyte population, and thereby to liver recovery. To investigate this issue, we
established a zebrafish model of liver regeneration in which the extent of hepatocyte
ablation can be controlled. Methods Hepatocytes were depleted by administration of …
Background & Aims
Biliary epithelial cells (BECs) are considered to be a source of regenerating hepatocytes when hepatocyte proliferation is compromised. However, there is still controversy about the extent to which BECs can contribute to the regenerating hepatocyte population, and thereby to liver recovery. To investigate this issue, we established a zebrafish model of liver regeneration in which the extent of hepatocyte ablation can be controlled.
Methods
Hepatocytes were depleted by administration of metronidazole to Tg(fabp10a:CFP-NTR) animals. We traced the origin of regenerating hepatocytes using short-term lineage-tracing experiments, as well as the inducible Cre/loxP system; specifically, we utilized both a BEC tracer line Tg(Tp1:CreERT2) and a hepatocyte tracer line Tg(fabp10a:CreERT2). We also examined BEC and hepatocyte proliferation and liver marker gene expression during liver regeneration.
Results
BECs gave rise to most of the regenerating hepatocytes in larval and adult zebrafish after severe hepatocyte depletion. After hepatocyte loss, BECs proliferated as they dedifferentiated into hepatoblast-like cells; they subsequently differentiated into highly proliferative hepatocytes that restored the liver mass. This process was impaired in zebrafish wnt2bb mutants; in these animals, hepatocytes regenerated but their proliferation was greatly reduced.
Conclusions
BECs contribute to regenerating hepatocytes after substantial hepatocyte depletion in zebrafish, thereby leading to recovery from severe liver damage.
Elsevier