Death-Associated Protein 6 (Daxx) Alleviates Liver Fibrosis by Modulating Smad2 Acetylation

Transforming growth factor-beta (TGF-beta) has been identified as an inducer of hepatocyte epithelial-mesenchymal transition (EMT), which triggers liver fibrosis. Death-associated protein 6 (Daxx) is known to be associated with the TGF-beta-induced apoptotic pathway, but the function of Daxx in liver fibrosis remains unknown. This study aimed to elucidate the role of Daxx in liver fibrosis. We used liver fibrosis tissues from humans and mice to assess Daxx expression. EMT properties and TGF-beta signaling pathway activation were investigated in the Daxx-overexpressing FL83B cell line. The therapeutic effect of Daxx was investigated in a mouse model of liver fibrosis by the hydrodynamic injection of plasmids. The expression of Daxx was markedly decreased in hepatocytes from fibrotic human and mouse livers, as well as in hepatocytes treated with TGF-beta in vitro. The overexpression of Daxx inhibited the EMT process by interfering with the TGF-beta-induced phosphorylation of Smad2. Coimmunoprecipitation analysis confirmed that Daxx reduced the transcriptional activity of Smad2 by binding to its MH1 domain and interfering with Smad2 acetylation. In addition, the therapeutic delivery of Daxx alleviated liver fibrosis in a thioacetamide-induced fibrosis mouse model. Overall, our results indicate that Daxx could be a potential therapeutic target to modulate fibrogenesis, as well as a useful biomarker for liver fibrosis.

Automated summary

The study revealed that the expression of Daxx was significantly decreased in fibrotic liver tissues, and overexpression of Daxx inhibited the EMT process by interfering with TGF-beta-induced phosphorylation of Smad2. Daxx was found to reduce the transcriptional activity of Smad2 by binding to its MH1 domain and interfering with Smad2 acetylation, suggesting its potential as a therapeutic target for liver fibrosis.