studies

1030A AASLD ABSTRACTS HEPATOLOGY, October, 2015
Disclosures:
Qin Ning - Advisory Committees or Review Panels: ROCHE, NOVARTIS, BMS,
MSD, GSK; Consulting: ROCHE, NOVARTIS, BMS, MSD, GSK; Grant/Research
Support: ROCHE, NOVARTIS, BMS; Speaking and Teaching: ROCHE, NOVAR-
TIS, BMS, MSD, GSK
The following authors have nothing to disclose: Di Wu, Weiming Yan, Guang
Chen, Meifang Han
1684
IFN-α-mediated Base Excision Repair Pathway Correlates
with Antiviral Response Against Hepatitis B Virus
Infection
Yong Li 1 , Yuchen Xia 3 , Meifang Han 2 , Guang Chen 2 , Wolfgang
E. Thasler 4 , Xiaoping Luo 1 , Ulrike Protzer 3 , Qin Ning 2 ; 1 Tongji
Hospital, Tongji Medical College, Huazhong University of Science
and Technology, Wuhan, China; 2 Department and Institute
of Infectious Diseases, Tongji Hospital, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan, China;
3 Institute of Virology, TechnischeUniversität München–Helmholtz
Zentrum München, Munich, Germany; 4 Department of General,
Visceral, Ludwig Maximilians University, Munich, Germany
Previous studies identified APOBEC family as base excision
repair (BER) proteins with enzymatic activity through deamination
of a cytidine base in DNA and/or RNA. As an
enzyme, APOBEC is therefore part of an antiviral effector repertoire
against hepatitis B virus (HBV) infection by interferon
(IFN). Additionally, other BERs, namely NEIL3 and TDG, are
expressed in liver and are regulated by IFN-α in hepatocytes.
We thus hypothesized that the responses to IFN-α treatment of
chronic hepatitis B (CHB) patients are relevant to IFN-induced
deaminases and BER genes. Ten CHB patients treated with
PEGylated IFN-α for 48 or 96 weeks, and six CHB-treatment
naïve patients as controls were recruited. Response to IFN
treatment was defined as HBV DNA 1 log10IU/
ml. Blood and liver samples were collected, and APOBEC3
and other BER genes measured by real-time PCR. The correlations
between BER gene expression levels and IFN treatment
responses were studied in these patients as well as in primary
human hepatocytes (PHH) and terminally differentiated HepRG
cells in vitro. Compared to treatment-naive patients, APO-
BEC3-A,-B, -C, -DE, and -G mRNA levels were up-regulated in
IFN-treated subjects. APOBEC3-A was significantly increased
in IFN-treated responders than non-responders. In contrast,
other BER genes, NEIL3 and TDG, were down-regulated in both
IFN-treated patients and in IFN-treated PHH and HepRG cells.
APOBEC3 and BER gene expression at treatment endpoints
partially correlated with the corresponding degree of HBsAg/
HBV DNA decline and DNA level. Our study suggests that the
expression levels of editing enzymes APOBEC3-A, -C, -F, -G,
and NEIL3 and TDG correlates with IFN treatment responses in
CHB patients, which may serve as biomarkers for CHB disease
management.
Disclosures:
Ulrike Protzer - Advisory Committees or Review Panels: GILEAD, Roche, MedImmune;
Board Membership: University Hospital Cologne; Grant/Research Support:
Janssen, Roche
Qin Ning - Advisory Committees or Review Panels: ROCHE, NOVARTIS, BMS,
MSD, GSK; Consulting: ROCHE, NOVARTIS, BMS, MSD, GSK; Grant/Research
Support: ROCHE, NOVARTIS, BMS; Speaking and Teaching: ROCHE, NOVAR-
TIS, BMS, MSD, GSK
The following authors have nothing to disclose: Yong Li, Yuchen Xia, Meifang
Han, Guang Chen, Wolfgang E. Thasler, Xiaoping Luo
1685
Hepatitis B virus down regulates the expression levels of
Vitamin D receptor in hepatocellular carcinoma (HepG2)
transfected cells thereby preventing the inhibition of
viral transcription and production by Vitamin D
Neta Gotlieb 1 , Irina Tachlytski 1 , Maya Sultan 1 , Michal Safran 1 ,
Ziv Ben Ari 1,2 ; 1 Liver Disease Center, Sheba Medical Center, Tel
Hashomer, Israel; 2 The Sackler School of Medicine, Tel Aviv University,
Tel-Aviv, Israel
Vitamin D is an important immune modulator that plays an
emerging role in both the innate and adaptive immune systems.
Certain viruses as the HIV-1 are capable to impair the innate
immune defense by down regulating the vitamin D receptor
(VDR) pathway. Recently it has been demonstrated that low
25(OH)D3 serum levels are associated with high levels of hepatitis
B Virus (HBV) replication in patients with HBV infection.
Our aim was to study in vitro the relationship between HBV
transcription and production and Vitamin D signaling pathway
and to explore the associated mechanism(s). Methods: To measure
HBV transcription and production we used qRT-PCR on
RNA purified from HBV-transfected hepatocellular carcinoma
HepG2 cells (HepG2 215) using primers specific to RNA-
HBV. In addition, the level of HBV replication was evaluated
by determining the concentrations of HBsAg levels in the cell
culture medium of HepG2 215 using specific enzyme-linked
immunosorbent (Elisa) assay. cccDNA levels were quantified
using qRT-PCR on DNA extracted from HepG2 215 cells. The
level of HBV transcription and production was assessed with
and without the administration of vitamin D (0-200mM) or its
active metabolite calcitriol (0-100 nM) for 48 or 72 hours. VDR
and IFNβ transcripts expression level were assessed by qRT-
PCR. Levels were compared in RNAs purified from HepG2 cells
(control) versus HepG2 215. Results: The expression level of
VDR transcript in HepG2 215 cells was statistically much lower
compared with non-transfected HepG2 cells. Furthermore, the
administration of vitamin D or calcitriol did not suppress the
secretion of HBsAg, the cccDNA expression and the HBVRNAs
level in HepG2 215 compared to cells which were not treated
with Vitamin D. Increasing the dose of both vitamin D and
calcitriol did not affect these findings. In addition, the administration
of Vitamin D or calcitriol induced interferon signaling
pathway, resulting in up-regulation of IFNβ expression level in
HepG2 cells, however, no such increase was observed in the
HepG2 215 HBV transfected cells. Conclusions: Our results
indicate for the first time that VDR expression level is down-regulated
in HBV-transfected HepG2 cells thereby preventing vitamin
D to affect transcription and production of the HBV in
vitro. Furthermore, these findings suggest that HBV might use
this mechanism to avoid the immunological defense system by
affecting the interferon signaling pathway and the expression
of the IFNβ.
Disclosures:
The following authors have nothing to disclose: Neta Gotlieb, Irina Tachlytski,
Maya Sultan, Michal Safran, Ziv Ben Ari
1686
The role of HBV quasispecies evolution in HBeAg-negative
reactivation
Guan Huei Lee 1,2 , Hui Heng Chong 2 , Seng Gee Lim 2 ; 1 Medicine,
National University Health System, Singapore, Singapore; 2 Medicine,
Yong Loo Lin School of Medicine, Singapore, Singapore
Background: HBeAg negative chronic hepatitis B reactivation is
characterized by increased levels of HBV DNA accompanied
by abnormal ALT, and occasionally severe hepatitis B flare.