Transmembrane protein 88 attenuates liver fibrosis by promoting apoptosis and reversion of activated hepatic stellate cells.

Transmembrane protein 88 (Tmem88) is a crucial inhibitor for Wnt/β-catenin pathway in the development of myocardial cells. Due to the important role of β-catenin in the activation and proliferation of hepatic stellate cells (HSCs), it is necessary to investigate the function of Tmem88 in HSCs. In this study, we found that Tmem88 expression was decreased in the human liver fibrotic tissues, primary HSCs from fibrotic mice and activated HSC-T6 cells. Functionally, Tmem88 could inhibit HSCs activation and proliferation by blocking Wnt/β-catenin pathway, and promoted the apoptosis of activated HSCs by initiating Bcl-2/Bax/Caspase3 pathway. Moreover, the level of DNA metyltransferase 3a (Dnmt3a) was upregulated in activated HSCs, and siRNA-mediated Dnmt3a silencing led to Tmem88 restoration. These results indicated that Tmem88 played an important role in HSCs activation, proliferation and apoptosis, and Tmem88 expression might be modulated by Dnmt3a.