Long non-coding RNA WAC antisense RNA 1 mediates hepatitis B virus replication <em>in vitro</em> by reinforcing miR-192-5p/ATG7-induced autophagy

Long non-coding RNA WAC antisense RNA 1 (lncRNA WAC-AS1) is involved in the replication of the hepatitis B virus (HBV). The purpose of this study was to determine its functions and specific mechanism. The levels of lncRNA WAC-AS1, RNA (miR)-192-5p and were examined in serum of HBV-infected patients and in HepG2.2.15 cells using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blotting. Using the database starBase, the target binding sites of lncRNA WAC-AS1 and miR-192-5p were predicted and confirmed by dual-luciferase reporter assay and RNA pull-down assay. The expression of pgRNA and HBV DNA was determined by qRT-PCR, while the levels of HBeAg and HBsAg were measured by enzyme-linked immunosorbent assay (ELISA). Using laser scanning confocal microscopy, the light chain 3 (LC3) expression was analyzed. qRT-PCR and Western blotting were used to assess the expression of beclin-1, p62, and LC3I/II. Overexpression of lncRNA WAC-AS1, upregulation of ATG7. and downregulation of miR-192-5p were observed in the serum of HBV-infected patients and the in vitro model. miR-192-5p directly targets lncRNA WAC-AS1. LncRNA WAC-AS1 was downregulated in lncRNA WAC-AS1-shRNA‒transfected cells. miR-192-5p was upregulated in lncRNA WAC-AS1-shRNA-transfected cells and downregulated in cells transfected with a miR-192-5p inhibitor. In HepG2 2.15 cells, the downregulation of lncRNA WAC-AS1 inhibited HBV replication and autophagy. In contrast, the miR-192-5p inhibitor-transfected group exhibited the opposite results, and ATG7 overexpression reversed the effects of miR-192-5p mimic or lncRNA WAC-AS1-shRNA on HBV replication and cell autophagy. Our findings indicate that lncRNA WAC-AS1 regulates HBV replication by reinforcing the autophagy induced by miR-192-5p/ATG7. Consequently, lncRNA WAC-AS1 may serve as a therapeutically-promising target in HBV patients.