LDL uptake assay

Fluorescent Dil-LDL (10 μg/ml, Fisher Scientific) was substituted for LDL in treatment medium during the final 4-h treatment period of the 27OH supplementation experiment, and cells that did not receive Dil-LDL were used to control for background fluorescence. Cells were washed once with PBS and lysed in RIPA buffer. Fluorescence was quantified in the cell lysate, and a BCA protein assay was then performed. Total protein concentration was used to normalize Dil fluorescence values.