|
Experimental Genetics Group
J Neurosci. 2002 May 1;22(9):3445-53. Dewachter I1, Reversé D2, Caluwaerts N1, Ris L2, Kuipéri C1, Van den Haute C1, Spittaels K1, Umans L1, Serneels L1, Thiry E1, Moechars D3, Mercken M3, Godaux E2, Van Leuven F1. 1Experimental Genetics Group, Katholieke Universiteit Leuven, Leuven, Belgium. 2Laboratory of Neuoscience, University of Mons-Hainaut, Mons, Belgium. 3Janssen Research Foundation, Beerse Belgium. In the brain of Alzheimer's disease (AD) patients, neurotoxic amyloid peptides accumulate and are deposited as senile plaques. A major therapeutic strategy aims to decrease production of amyloid peptides by inhibition of gamma-secretase. Presenilins are polytopic transmembrane proteins that are essential for gamma-secretase activity during development and in amyloid production. By loxP/Cre-recombinase-mediated deletion, we generated mice with postnatal, neuron-specific presenilin-1 (PS1) deficiency, denoted PS1(n-/-), that were viable and fertile, with normal brain morphology. In adult PS1(n-/-) mice, levels of endogenous brain amyloid peptides were strongly decreased, concomitant with accumulation of amyloid precursor protein (APP) C-terminal fragments. In the cross of APP[V717I]xPS1 (n-/-) double transgenic mice, the neuronal absence of PS1 effectively prevented amyloid pathology, even in mice that were 18 months old. This contrasted sharply with APP[V717I] single transgenic mice that all develop amyloid pathology at the age of 10-12 months. In APP[V717I]xPS1 (n-/-) mice, long-term potentiation (LTP) was practically rescued at the end of the 2 hr observation period, again contrasting sharply with the strongly impaired LTP in APP[V717I] mice. The findings demonstrate the critical involvement of amyloid peptides in defective LTP in APP transgenic mice. Although these data open perspectives for therapy of AD by gamma-secretase inhibition, the neuronal absence of PS1 failed to rescue the cognitive defect, assessed by the object recognition test, of the parent APP[V717I] transgenic mice. This points to potentially detrimental effects of accumulating APP C99 fragments and demands further study of the consequences of inhibition of gamma-secretase activity. In addition, our data highlight the complex functional relation of APP and PS1 to cognition and neuronal plasticity in adult and aging brain. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
![]() |
Copyright © Katholieke Universiteit Leuven | Comments on the content: Fred Van Leuven Production:Annick Vogels| Most recent update: October 21, 2009 | Disclaimer URL: http://med.kuleuven.be/legtegg/ |