Mutant presenilin 1 increases the expression and activity of BACE1.
Mutations of the presenilin 1 (PS1) gene are the most common cause of early onset familial Alzheimer disease (FAD). PS1 mutations alter the activity of the gamma-secretase on the beta-amyloid precursor protein (APP), leading to selective overproduction of beta-amyloid (Abeta) 42 peptides, the species that forms oligomers that may exert toxic effects on neurons. Here we show that PS1 mutations, expressed both transiently and stably, in non-neuronal and neuronal cell lines increase the expression and the activity of the beta-secretase (BACE1), the rate-limiting step of Abeta production. Also, BACE1 expression and activity are elevated in brains of PS1 mutant knock-in mice compared with wild type littermates as well as in cerebral cortex of FAD cases bearing various PS1 mutations compared with in sporadic AD cases and controls. The up-regulation of BACE1 by PS1 mutations requires the gamma-secretase cleavage of APP and is proportional to the amount of secreted Abeta42. Abeta42, and not AICD (APP intracellular domain), is indeed the APP derivative that mediates the overexpression of BACE1. The effect of PS1 mutations on BACE1 may contribute to determine the wide clinical and pathological phenotype of early onset FAD.
Giliberto
Luca
L
Department of Neuroscience, Ophthalmology, and Genetics and Internal Medicine and Medical Specialties, University of Genova, Genova, Italy.
Borghi
Roberta
R
Piccini
Alessandra
A
Mangerini
Rosa
R
Sorbi
Sandro
S
Cirmena
Gabriella
G
Garuti
Anna
A
Ghetti
Bernardino
B
Tagliavini
Fabrizio
F
Mughal
Mohamed R
MR
Mattson
Mark P
MP
Zhu
Xiongwei
X
Wang
Xinglong
X
Guglielmotto
Michela
M
Tamagno
Elena
E
Tabaton
Massimo
M
D053829:Amyloid Precursor Protein Secretases / Q000235:genetics / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D053764:Presenilin-1 / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics; D015854:Up-Regulation
D016564:Amyloid beta-Protein Precursor; D053764:Presenilin-1; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse