Oxidized LDL induces the expression of ALBP/aP2 mRNA and protein in human THP-1 macrophages

Abstract

The adipocyte lipid-binding protein (ALBP/aP2) belongs to a multigene family of fatty acid and retinoid transport proteins. This protein is abundantly expressed in the cytoplasm and nuclear region of adipocytes and is postulated to serve as a lipid shuttle, solubilizing hydrophobic fatty acids and delivering them to the appropriate metabolic system for utilization. This report demonstrates that human cholesterol-loaded THP-1 macrophages express ALBP/aP2 and that its expression can be stimulated by oxidized low density lipoprotein (oxLDL). The increase in mRNA expression was paralleled by a similar increase in ALBP/aP2 protein. The increase in ALBP/aP2 mRNA and protein in oxLDL-stimulated THP-1 macrophages is concentration and time dependent and is inhibited by treatment of the cells with an antioxidant inhibitor of nuclear factor-κB (NF-κB), pyrrolidine dithiocarbamate (PDTC), and with protein kinase C (PKC) inhibitors bisindolylmaleimide I and Ro-31-8220. These results suggest that activation of both NF-κB and PKC signaling pathways is necessary for oxLDL-induced ALBP/aP2 gene expression in THP-1 macrophages and that the upregulation of the fatty acid carrier may be a necessary event in foam cell formation.—Fu, Y., N. Luo, and M. F. Lopes-Virella. Oxidized LDL induces the expression of ALBP/aP2 mRNA and protein in human THP-1 macrophages. J. Lipid Res. 2000. 41: 2017–2023.

Keywords

• oxidized low density lipoprotein
• signaling pathways
• atherosclerosis