Cell Culture and Treatment

The human hepatoblastoma cells (HepG2.2.15) were donated by liver disease laboratory of the Zhejiang University Medical Center (Zhejiang, China). HepG2.2.15 cells are derived from HepG2 cells, which are transfected with two complete HBV genes segments and can stably express HBV DNA. The medium of HepG2.2.15 cells contains all of the virus particles (spherical and filamentous HBsAg particles and empty and full Dane particles) and HepG2.2.15 cells are the typical cell type used for hepatitis B virus infection. HepG2.2.15 cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum (FBS) and 1% penicillin/streptomycin. Cells were maintained at 37 °C and 5% CO₂. Palmitic acid (Sigma-Aldrich) was dissolved in 10% fatty acid-free bovine serum albumin (BSA) at a stock concentration of 5mM and stored at −20°C. HepG2.2.15 cells were incubated with various concentrations of palmitic acid (0–1 mM) or the BSA control and FBS was not added to the medium. After 24 hours, we measured cell viability using a Cell Counting Kit-8 (CCK-8 Kit) assay in accordance with the manufacturer’s instructions The cells or supernatants were used for the assays. HepG2.2.15 cells were incubated with palmitic acid (0.5mM) to stimulate lipid accumulation.