Conversion of the soluble, nontoxic amyloid β-protein (Aβ) into an aggregated, 
toxic form rich in β-sheets is a key step in the onset of Alzheimer's disease 
(AD). It has been suggested that Aβ induces changes in neuronal membrane 
fluidity as a result of its interactions with membrane components such as 
cholesterol, phospholipids, and gangliosides. Gangliosides are known to bind Aβ. 
A complex of GM1 and Aβ, termed "GAβ", has been identified in AD brains. 
Abnormal ganglioside metabolism also may occur in AD brains. We have reported an 
increase of Chol-1α antigens, GQ1bα and GT1aα, in the brain of transgenic mouse 
AD model. GQ1bα and GT1aα exhibit high affinities to Aβs. The presence of 
Chol-1α gangliosides represents evidence for genesis of cholinergic neurons in 
AD brains. We evaluated the effects of GM1 and Aβ1-40 on mouse neuroepithelial 
cells. Treatment of these cells simultaneously with GM1 and Aβ1-40 caused a 
significant reduction of cell number, suggesting that Aβ1-40 and GM1 
cooperatively exert a cytotoxic effect on neuroepithelial cells. An 
understanding of the mechanism on the interaction of GM1 and Aβs in AD may 
contribute to the development of new neuroregenerative therapies for this 
disorder.