Effects of apolipoproteinA1 on reverse cholesterol transport and expression of ATP-binding cassette transporter A1 in human acute monocytic leukemia cell line macrophage-derived foam cells / 中华老年医学杂志

ABSTRACT

Objective To investigate the effects of apolipoproteinA1 (apoA1) on levels of cholesterol, cholesteryl ester (CE), and expression of ATP-bindiag cassette transporter A1 (ABCA1) in human acute monocytie leukemia cell line (THP-1) macrophage-derived foam cells.Methods The cultured THP-1 cells were induced into foam cells by exposing first to phorbol myristate acetate (PMA, 50 ng/ml) for 48 h, and then to oxidized-low density lipoprotein (ox-LDL, 50μg/ml) for 48 h.Under treatment of apoA1 in different doses (5, 10, 15 and 20 μg/ml) and one simple dose (10 μg/ml) for different time (6, 12 and 24 h), THP-1 macrophage-derived foam cells were incubated to observe the expression of cholesterol and ABCA1.The concentrations of cellular total cholesterol (TC), free cholesterol (FC) and CE were determined by oxidization enzymatic methods.Oil red O dyeing experiment was used to show the cellular lipid droplets in the cells.The expression of ABCA1 was tested by immunofluorescence method.Reverse transcription-polymerase chain reaction was applied to investigate mRNA expression of ABCA1.Results The THP-1 cells turned into typical foam cells after treated with PMA (50 ng/ml) for 48 h, and ox-LDL (50 μg/ml) for 48 h.apoA1 could lower the levels of TC, FC and CE in THP-1 macrophage-derived foam cells in a dose-dependent and a time-dependant manner, apoA1 could increase the expression of ABCA1 protein in THP-1maerophage-derived foam cells without up-regulation of mRNA.Antibody of ABCA1 could up- regulate the expression of ABCA1.Conclusions apoA1 may decrease the levels of cholesterols in THP-1 macrophage-derived foam cells, by promoting the expression of ABCA1 and the reverse cholesterol transport of high density lipoprotein.