Age-related changes of Alzheimer's disease-associated proteins in cynomolgus monkey brains.
We characterized senile plaques (SPs) immunohistochemically in cynomolgus monkey brains and also examined age-related biochemical changes of Alzheimer's disease (AD)-associated proteins in these brains from monkeys of various ages. In the neocortex of aged monkeys (>20 years old), we found SPs but no neurofibrillary tangles (NFTs). Antibodies against beta-amyloid precursor protein (APP) or apolipoprotein E (ApoE) stained SPs; however, the pattern of immunostaining was different for the two antigens. APP was present only in swollen neurites, but ApoE was present throughout all parts of SPs. Western blot analysis revealed that the pattern of APP expression changed with age. Although full-length APP695 protein was mainly expressed in brains from young monkeys (4-years-old), the expression of full-length APP751 protein was increased in brains from older monkeys (>20 years old). Biochemical analyses also showed that levels of various AD-associated proteins increased significantly with age in nerve ending fractions. Both SP-associated (APP) and NFT-associated proteins (tau, activated glycogen synthase kinase 3beta, cyclin dependent kinase 5, p35, and p25) accumulated in the nerve ending fraction with increasing age; however, we found no NFTs or paired helical filaments of tau in aged cynomolgus monkey brains. This age-related accumulation of these proteins in the nerve ending fraction was similar to that observed in our laboratory previously for presenilin-1 (PS-1). The accumulation of these SP-associated proteins in this fraction may be a causal event in the spontaneous formation of SPs; thus, SPs may be formed initially in nerve endings. Taken together, these results suggest that intensive investigation of age-related changes in the nerve ending and in axonal transport will contribute to a better understanding of the pathogenesis of neurodegenerative disorders such as AD.
Kimura
Nobuyuki
N
Department of Biomedical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. aa07190@mail.ecc.u-tokyo.ac.jp
Tanemura
Kentaro
K
Nakamura
Shin-ichiro
S
Takashima
Akihiko
A
Ono
Fumiko
F
Sakakibara
Ippei
I
Ishii
Yoshiyuki
Y
Kyuwa
Shigeru
S
Yoshikawa
Yasuhiro
Y
D000375:Aging; D000544:Alzheimer Disease / Q000209:etiology; D016564:Amyloid beta-Protein Precursor / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D000818:Animals; D001057:Apolipoproteins E / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D015153:Blotting, Western; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D001923:Brain Chemistry; D005260:Female; D015151:Immunoblotting; D007150:Immunohistochemistry; D008252:Macaca fascicularis; D008297:Male; D016874:Neurofibrillary Tangles / Q000378:metabolism; D058225:Plaque, Amyloid / Q000378:metabolism*; D011506:Proteins / Q000032:analysis / Q000276:immunology
D016564:Amyloid beta-Protein Precursor; D001057:Apolipoproteins E; D011506:Proteins