“…This oxysterol, frequently detected at enhanced levels in atherosclerotic plaques (8) and in the plasma of patients with high cardiovascular risks (42), is a potent inducer of apoptosis characterized by various cellular dysfunctions: phosphatidylserine externalization (43), loss of mitochondrial transmembrane potential, cytosolic release of cytochrome c, activation of caspase-9 and -3 with subsequent enhanced activity of caspase-3, degradation of poly(ADPribose) polymerase (36), morphologic nuclear changes (cells with swollen, condensed, and/or fragmented nuclei) (44), and formation of multilamellar cytoplasmic structures (22,23). Because multilamellar cytoplasmic structures (also termed myelin figures), considered as lipid storage organelles (21), were observed in aortic cells from cholesterol-fed rabbits (25,26), the effects of 7KC (20 g/ ml) on the cellular lipid content were studied on human promonocytic U937 cells after staining with filipin (27,28) and NR (29,34). Moreover, because an increased cellular content of 7KC can disturb numerous signaling pathways (12), the interaction between 7KC and cellular lipids was investigated by FRET.…”