Lipid raft ER signalosome malfunctions in menopause in Alzheimer's disease

Abstract

The increase in the incidence of Alzheimer's disease (AD) in old women may be attributable to estrogen deficiency, and estrogen replacement therapy may be useful in preventing or delaying the onset of this disease. In neuronal membranes, 17b-estradiol interacts with estrogen receptors (mERs) located in lipid raft signalosomes which trigger neuroprotective responses by anchoring to scaffolding caveolin-1 complexed with other proteins. We suggest that mER-signalosome malfunctions in AD and by menopause due to development of aberrations in these microstructures. Here, we report that mER dissociates from a voltage-dependent anion channel (VDAC), and that progressive dephosphorylation of VDAC1 enhances neurotoxicity. mER dissociates from caveolin-1 and other neuroprotective proteins, including insulin-like growth factor 1 receptor beta. Similar signalosome disarrangements are observed in AD patients. Moreover, in AD, lipid rafts exhibit alterations in lipid composition, and these changes cause an increase in liquid-ordered as compared to controls. Together, the data show that AD and menopause lead to disruption in the lipid raft structure, and disfunctioning of ERalpha and other neuroprotectors integrated into these signalosomes.