Figure 1

tyrHDL requires ABCA1 to enhance depletion of ACAT-accessible cholesterol. Human skin fibroblasts from a normal donor and 2 unrelated Tangier Disease (TD) subjects were grown to confluence, loaded with non-lipoprotein cholesterol for 24 h, equilibrated for 24 h in DMEM containing 1 mg/ml BSA, and then incubated in the same medium plus the indicated concentration of HDL or tyrHDL for 16 h. To measure residual ACAT-accessible cholesterol, cells were then incubated with [¹⁴C]oleate for 1 h, and cholesteryl [¹⁴C]esters present in cellular lipid extracts were determined. Results are expressed as percentage of cholesterol esterification in cells untreated with HDL or tyrHDL. Avg ± SD of quadruplicates, representative of 3 experiments. *, p < 0.01 when compared with tyrHDL-treated cells.