Disease-specific serum
miRNA profiles may serve as
biomarkers and might reveal potential new avenues for
therapy. An HBV-specific serum
miRNA profile associated with HBV
surface antigen (
HBsAg) particles has recently been reported, and AGO2 and
miRNAs have been shown to be stably associated with
HBsAg in serum. We identified HBV-associated serum
miRNAs using the Toray 3D array system in 10 healthy controls and 10 patients with
chronic hepatitis B virus (HBV)
infection. 19 selected
miRNAs were then measured by quantitative RT-PCR in 248 chronic HBV patients and 22 healthy controls.
MiRNA expression in serum versus liver tissue was also compared using biopsy samples. To examine the role of AGO2 during the HBV life cycle, we analyzed intracellular co-localization of AGO2 and HBV core (
HBcAg) and surface (
HBsAg)
antigens using immunocytochemistry and proximity
ligation assays in stably transfected HepG2 cells. The effect of AGO2 ablation on viral replication was assessed using
siRNA. Several
miRNAs, including miR-122, miR-22, and miR-99a, were up-regulated at least 1.5 fold (P<2E-08) in serum of HBV-infected patients. AGO2 and
HBcAg were found to physically interact and co-localize in the ER and other subcellular compartments. HBs was also found to co-localize with AGO2 and was detected in multiple subcellular compartments. Conversely, HBx localized non-specifically in the nucleus and cytoplasm, and no interaction between AGO2 and HBx was detected.
SiRNA ablation of AGO2 suppressed production of HBV
DNA and HBs
antigen in the supernatant.
CONCLUSION: