Canonical Wnt signaling maintains the quiescent stage of hepatic stellate cells

It is well known that hepatic stellate cells (HSC) develop into cells, which are thought to contribute to liver fibrogenesis. Recent data suggest that HSC are progenitor cells with the capacity to differentiate into cells of endothelial and hepatocyte lineages. The present study shows that beta-catenin-dependent canonical Wnt signaling is active in freshly isolated HSC of rats. Mimicking of the canonical Wnt pathway in cultured HSC by TWS119, an inhibitor of the glycogen synthase kinase 3 beta, led to reduced beta-catenin phosphorylation, induced nuclear translocation of beta-catenin, elevated glutamine synthetase production, impeded synthesis of alpha-smooth muscle actin and Wnt5a, but promoted the expression of glial fibrillary acidic protein, Writ I Ob, and paired-like homeodomain transcription factor 2c. In addition, canonical Writ signaling lowered DNA synthesis and hindered HSC from entering the cell cycle. The findings demonstrate that beta-catenin-dependent Writ signaling maintains the quiescent state of HSC and, similar to stem and progenitor cells, influences their developmental fate. (C) 2007 Elsevier Inc. All rights reserved.