Inhibition of histone deacetylases stimulates HBV replication independent of protein X

Abstract

ABSTRACT  Aim: HBV expresses an accessory protein called X (HBx), which supports HBV replication by increasing transcription from episomal templates. Here, we investigate whether HBx augments HBV replication by interfering with the deacetylation of HBV DNA associated histones by histone deacetylases (HDACs). Materials & methods: To study the effect of HBx on episomal transcription, we transfected HEK 293 cells with luciferase-expressing constructs together with HBx in the presence and absence of HDAC inhibitors. We confirmed our results in the context of the full HBV replication cycle in HepG2 cells. Results & conclusion: Inhibition of HDAC activity and HBx expression stimulated transcription from episomal DNA independently, showing that HBx does not affect the histone deacetylation. HDAC inhibitors also augmented HBV replication in vitro independent of HBx expression. This suggests that treatment with HDAC inhibitors can (re)activate HBV infection in patients with cleared or ongoing HBV infection.