Effect of apolipoprotein E on cell viability in a human neuroblastoma cellline: influence of oxidation and lipid-association

Apolipoprotein E (apoE) whose polymorphic expression is widely associated w ith Alzheimer's disease (AD) is one of the most studied protein present in cerebral amyloid deposits. Native or fragments of apoE are known to exert n eurotoxic effects. We evaluated the effects of apoE oxidation and lipid-ass ociation on the viability of human neuroblastoma IMR32 cells. We show that apoE affects cell viability only when it is lipid-associated and applied at a concentration near to that found in plasma, and this whatever the isofor m. Oxidized phospholipid-associated apoE has a similar impact on cell viabi lity. These findings show the necessity of including apoE into phospholipid s when studying its effect on cell metabolism and underline the probable in tervention of surface heparan sulfate proteoglycans (HSPG). It also warrant s further studies in order to delineate the pathophysiological importance o f apoE. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.