Long chain acyl-CoA synthetase 3-mediated phosphatidylcholine synthesis is required for assembly of very low density lipoproteins in human hepatoma Huh7 cells.

Hepatocytes play a crucial role in regulating lipid metabolism by exporting cholesterol and triglyceride into plasma through secretion of very low density lipoproteins (VLDL). VLDL production is also required for release of hepatitis C virus (HCV) from infected hepatocytes. Here, we show that long chain acyl-CoA synthetase 3 (ACSL3) plays a crucial role in secretion of VLDL and HCV from hepatocytes. In cultured human hepatoma Huh7 cells, ACSL3 is specifically required for incorporation of fatty acids into phosphatidylcholine. In cells receiving small interfering RNA targeting ACSL3, secretion of apolipoprotein B, the major protein component of VLDL, was inhibited and the lipoprotein was rapidly degraded. This inhibition in secretion was completely eliminated when these cells were treated with phosphatidylcholine. Treatment of cells with small interfering RNA targeting ACSL3 also inhibited secretion of HCV from Huh7-derived cells. These results identify ACSL3 as a new enzymatic target to limit VLDL secretion and HCV infection.