Apolipoprotein E affects the amount, form, and anatomical distribution of amyloid beta-peptide deposition in homozygous APP(V717F) transgenic mice

Apolipoprotein E (apoE) has been implicated as a risk factor for Alzheimer' s disease and in the deposition, fibrillogenesis, and clearance of the amyl oid beta-peptide (A beta). To examine the in vivo interactions between apoE and A beta deposition, we examined 12-month-old transgenic (tg) mice expre ssing human amyloid precursor protein (APP) with the V717F mutation (APP(V7 17F) homozygous) on an APOE null background. Elimination of APOE resulted i n a redistribution and alteration in the character of A beta deposition in homozygous APP(V717F) tg mice, with a dramatic reduction in cortical and de ntate gyrus deposition, prominent increase in diffuse CA1 and CA3 depositio n, and prevention of the formation of thioflavin-S-positive deposits. These alterations in A beta deposition were not mediated by significant changes in regional APP expression, low-density lipoprotein receptor-related protei n expression, or soluble A beta levels. Thus, apoE in APP(V717F) tg mice no t only affects the amount and form of A beta deposition, but also the anato mical distribution of diffuse A beta deposits. The APP(V717F) tg mouse can serve as a model to investigate genetic influences on the vulnerability of specific neuroanatomical regions to A beta deposition.