Inducible expression of Wnt genes during adult hepatic stem/progenitor cell response.

In injured livers where hepatocyte growth is severely limited, facultative hepatic stem/progenitor cells, termed oval cells in rodents, are known to emerge and contribute to the regeneration process. Here, we investigated a possible involvement of Wnt signaling during mouse oval cell response and found significant upregulation of several Wnt genes including Wnt7a, Wnt7b, and Wnt10a. Accordingly, increase of beta-catenin protein was observed in oval cell compartments. Pharmacological activation of the canonical Wnt/beta-catenin signaling induced proliferation of cultured hepatic stem/progenitor cell lines. These results together implicate the role of Wnt/beta-catenin signaling in adult hepatic stem/progenitor cell response.