Transforming Growth Factor-β1 Suppresses Hepatitis B Virus Replication by the Reduction of Hepatocyte Nuclear Factor-4α Expression

Abstract

Several studies have demonstrated that cytokine-mediated noncytopathic suppression of hepatitis B virus (HBV) replication may provide an alternative therapeutic strategy for the treatment of chronic hepatitis B infection. In our previous study, we showed that transforming growth factor-beta1 (TGF-β1) could effectively suppress HBV replication at physiological concentrations. Here, we provide more evidence that TGF-β1 specifically diminishes HBV core promoter activity, which subsequently results in a reduction in the level of viral pregenomic RNA (pgRNA), core protein (HBc), nucleocapsid, and consequently suppresses HBV replication. The hepatocyte nuclear factor 4alpha (HNF-4α) binding element(s) within the HBV core promoter region was characterized to be responsive for the inhibitory effect of TGF-β1 on HBV regulation. Furthermore, we found that TGF-β1 treatment significantly repressed HNF-4α expression at both mRNA and protein levels. We demonstrated that RNAi-mediated depletion of HNF-4α was sufficient to reduce HBc synthesis as TGF-β1 did. Prevention of HNF-4α degradation by treating with proteasome inhibitor MG132 also prevented the inhibitory effect of TGF-β1. Finally, we confirmed that HBV replication could be rescued by ectopic expression of HNF-4α in TGF-β1-treated cells. Our data clarify the mechanism by which TGF-β1 suppresses HBV replication, primarily through modulating the expression of HNF-4α gene.

Doubly Spliced RNA of Hepatitis B Virus Suppresses Viral Transcription via TATA-Binding Protein and Induces Stress Granule Assembly

“…4G for a schematic of the truncations) were subcloned into the pShuttle/R vector (Clontech, USA), from which transcription in mammalian cells is driven by the cytomegalovirus immediate early (CMVie) promoter. For the HBV promoter analysis, the cDNAs of the core protein promoter (nucleotides 1636 to 1851), X promoter (nucleotides 1177 to 1376), I/X enhancer and core promoter (EnhI/C, nucleotides 947 to 1851), pre-S1 promoter (nucleotides 2710 to 2800), and pre-S2/S promoter (nucleotides 2960 to 3180) were subcloned into the pGL3-Basic luciferase expression plasmid (Promega, USA) using the MluI and HindIII restriction sites (35). The cDNAs of the simian virus 40 (SV40) early enhancer/promoter and the herpes simplex virus thymidine kinase (TK) promoter were also cloned into the pGL3-Basic expression plasmid to investigate the effects of 2.2DS-RNA on the transcriptional activity of non-HBV viral promoters.…”

CXCL9 Associated with Sustained Virological Response in Chronic Hepatitis B Patients Receiving Peginterferon Alfa-2a Therapy: A Pilot Study

“…Recently, we also demonstrated a correlation of IP-10 with higher hepatitis activity in patients with CHB [4]. Pro-inflammatory cytokines interferon-gamma (IFN-γ) and transforming growth factor beta (TGF-β) may also have roles in suppressing HBV replication [1,23,24]. However, the clinical significance of these cytokines and chemokines during PEG-IFN therapy is unclear.…”

Impact of host gene polymorphisms on susceptibility to chronic hepatitis B virus infection

“…This cytokine, as the most common TGF-β isoform, can regulate the immune system of the host that leads to the suppression of the HBV replication via the reduction of the hepatocyte nuclear factor-4-alpha (HNF4A) (Hong et al, 2012).…”