关键词: ATP结合盒转运子A1, 非酒精性脂肪性肝炎, 载脂蛋白A-Ⅰ

Abstract: Objective To explore a new therapy to change the lipid metabolism and prevent non-alcoholic steatohepatitis(NASH), to establish a cell model that overexpresses apolipoprotein A-Ⅰ(apoA-Ⅰ), which promotes cellular cholesterol efflux by interacting with ATP-binding cassette transporter A1(ABCA1). The effect and its molecular mechanism of apoA-Ⅰ overexpression on cellular lipid levels were evaluated in lipid-loaded cells to investigate the therapeutic effect of apoA-Ⅰ on NASH. Methods 1 Human liver cancer cell line BEL-7402 were treated with different concentrations and types of fatty acids for 6, 12 and 24 h, cellular lipid accumulation was determined by Oil Red O staining, and optimal concentration and time of fatty acid treatment were then established; 2 BEL-7402 cells were treated with different concentrations and types of fatty acids for 6, 12 and 24 h, and cell activity was determined by MTT; 3 Control plasmid and pcDNA3.0/apoA-I plasmid were transfected into BEL-7402 hepatocytes, and intracellular and extracellular apoA-Ⅰ protein levels were determined by Western blotting; 4 Cellular cholesterol, free fatty acid and triglyceride content of control cells and apoA-Ⅰ-overexpressive cells were determined respectively. Results 1 The lipid accumulation in BEL-7402 cells could be achieved by treatment with 200 μmol/L or 400 μmol/L fatty acids for 6, 12 and 24 h , and was both dose- and time-dependent. 2 Saturated fatty acid palmitic acid decreased the cell activity, and the inhibitory effect of cell growth is coming with increasing time and concentration of palmitic acid. 3 ApoA-Ⅰ can be overexpressed intracellularly and excreted extracellularly to facilitate ABCA1 to mediate the transport of cellular cholesterol and phospholipids. 4 The cholesterol, free-fatty acid and triglyceride content in apoA-Ⅰ-overexpressive cells were less than that in control BEL-7402 cells. Conclusion Compared with the control cells, the lipid accumulation including cholesterol, free-fatty acid and triglyceride in human hepatocytes was markedly down-regulated by apoA-Ⅰ overexpression. These findings suggest that apoA-Ⅰ overexpression may increase ABCA1-mediated lipid transport, and may have a therapeutic effect on NASH.

Key words: ATP-binding cassette transporter A1, non-alcoholic steatohepatitis, apolipoprotein A-Ⅰ