Oxysterol-induced rearrangement of the liquid-ordered phase: A possible link to Alzheimer's disease?

Abstract

Nearest-neighbor recognition measurements have been made for an exchangeable phospholipid (A) interacting with an exchangeable form of cholesterol (B) in host membranes derived from 1, 2-dipalmitoyl-sn-glycero-3- phosphocholine and varying concentrations of cholesterol, 7β- hydroxycholesterol (7β-OH), and 25-hydroxycholesterol (25-OH). Whereas partial replacement of cholesterol with 7β-OH strengthens the association between A and B, a similar substitution with 25-OH weakens this association. A model that accounts for this dichotomy, and the possible relevance of these findings to the cytotoxicity of 7β-OH and to Alzheimer's disease are briefly discussed. © 2009 American Chemical Society.