FIGURE 1.

Oxysterol regulation of ER cholesterol homeostasis. A, effect of oxysterols on sterol-regulated gene expression using a human low density lipoprotein receptor-luciferase reporter construct. ^**, p < 0.01 for 25-HC and 27-HC versus 7α-HC, 7β-HC, or 7-KC treatment; #, p < 0.01 for ent-25-HC treatment versus 7α-HC, 7β-HC, and 7-KC treatments. B, effect of oxysterols on PM-to-ER cholesterol movement. CHO cells were cultured in LPDS medium for 24 h. Cells were pulse-labeled with [³H]cholesterol-CD complexes for 10 min at 4 °C, and then incubated with 1 μm oxysterols in LPDS medium at 37 °C for 5 h. Cells were harvested and incorporated [³H]cholesterol into the cholesteryl esters determined. Assay was performed in triplicate and is presented as the percent esterification of total cell-associated radiolabel. Data are presented as means ± S.E. ^*, p < 0.05 for 25-HC and 27-HC treatments versus vehicle alone.