Objective       To investigate the role of fatty acid translocase FAT/CD36 in the palmitate-induced intracellular lipid accumulation in HepG2 cells and explore the underlying mechanism.       Methods      HepG2 cells were treated with 0

0.08

0.16 and 0.32  mmol/L palmitate. Western blotting

dual-luciferase assay

real-time PCR and polysome ribosome analysis were performed to detect the CD36 expression

promoter activity and protein transcriptional efficiency. Oil Red O staining and free fatty acids quantitative measurements were used to examine the intracellular lipid contents. The rate of fluorescent-labeled fatty acid uptake was measured under a fluorescent microscope. The effects of inhibited CD36 expression by RNA interference in HepG2 on intracellular lipid accumulation and fatty acid uptake under palmitate condition were also studied.       Results       Palmitate promoted CD36 expression in HepG2 cells

accompanied by an increase of CD36 promoter activity and the protein translation efficiency. In palmitate-treated cells

more lipid droplets were observed

and FFA contents were significantly higher than control group (240.17±19.83 vs 144.60±53.52  ng/mg

P0.05). Palmitate treatment also resulted in the rate of fatty acid uptake. In addition

the mRNA and protein levels of CD36 in the cells after CD36-siRNA transfection were only 58% and 50% of the cells transfected with NC-siRNA. In response to palmitate loading

CD36-siRNA-HepG2 showed less lipid droplets accumulation

and lower FFA contents compared with the NC-siRNA transfected HepG2 cells (98.38±14.18 vs 240.17±21.12  ng/mg

P0.05). The rate of fatty acid uptake was also slower in CD36-siRNA-HepG2 than in NC cells.       Conclusion       Palmitate promotes the expression of CD36 at transcriptional and translational levels

resulting in excess intracellular lipid accumulation in HepG2 cells.