ADAR1 Inhibits HBV DNA Replication via Regulating miR-122-5p in Palmitic Acid Treated HepG2.2.15 Cells

Abstract

Background and Aims

Changes in living standards and diet structure, non-alcoholic fatty liver disease (NAFLD) is prevalent globally, including in Asia, where chronic hepatitis B (CHB) is endemic. As such, cooccurrence of NAFLD with CHB is common in Asia. However, the pathogenesis underlying the onset of fatty liver in CHB prognosis has not been fully elucidated. Therefore, we aimed to investigate the effects and mechanisms of lipotoxicity on hepatitis B virus (HBV) DNA replication.

Methods

The expression of adenosine deaminase acting on RNA-1 (ADAR1) and miR-122 was evaluated in liver tissues from patients with CHB concurrent NAFLD. Palmitic acid-treated HepG2.2.15 cells were used as the cell model. The effect of lipotoxicity on HBV DNA replication was evaluated in vitro by transfecting the ADAR1 overexpression or knockdown lentiviral vector into HepG2.2.15 cells, respectively. qRT-PCR, western blotting and immunofluorescence were performed to determine ADAR1 expression.

Results

The expression of ADAR1 in the liver tissues of CHB patients with concurrent NAFLD was significantly down-regulated compared with that in CHB patients. Enforced expression of ADAR1 inhibited the HBV DNA replication, whereas ADAR1 knockdown resulted in increased HBV DNA expression in palmitic acid - treated HepG2.2.15 cells. Additionally, ADAR1 inhibited the HBV DNA replication by upregulating miR-122, which is most abundant in the liver and mainly inhibits HBV DNA replication.

Conclusions

ADAR1 may act as a suppressor of HBV replication in palmitic acid -treated HepG2.2.15 cells by increasing miR-122 levels. Thus, ADAR1 may serve as a potential biomarker and therapeutic target for CHB with concurrent NAFLD.

Graphical Abstract

Keywords:

• chronic hepatitis B
• non-alcoholic fatty liver disease
• ADAR1
• miR-122
• HBV DNA

Abbreviations

CHB, chronic hepatitis B; NAFLD, non-alcoholic fatty liver disease; ADAR1, adenosine deaminase acting on RNA-1; HCC, hepatocellular carcinoma; HBV, hepatitis B virus; CLD, chronic liver disease; CHC, chronic hepatitis C; ADAR, Adenosine Deaminases Acting on RNA; HBsAg, hepatitis B virus surface antigen; DMEM, Dulbecco’s modified Eagle’s medium; FBS, fetal bovine serum; BSA, bovine serum albumin; CCK-8 Kit, The Cell Counting Kit-8; PBS, phosphate-buffered saline; OD, optical density; GFP, green fluorescent protein; shRNA, short hairpin RN; HE, hematoxylin-eosin; qRT-PCR, quantitative real‑time polymerase chain reaction; BCA, bicinchoninic acid; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; PVDF, polyvinylidene fluoride; TBST, Tris-buffered saline plus Tween-20; DAB, diaminobenzidine; AST, aspartate aminotransferase; ALT, alanine aminotransferase; SDs, standard deviations; A-to-I, adenosine to inosine; EPO, erythropoietin; NTCP, sodium taurocholate cotransporting polypeptide.

Acknowledgment

Dr. Jie Li wishes to acknowledge the support from the National Natural Science Fund (No. 82170609, 81970545), Natural Science Foundation of Shandong Province (Major Project) (No. ZR2020KH006) and Ji’nan Science and Technology Development Project (No.202019079).

Disclosure

The authors report no conflicts of interest in this work.