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J Alzheimers Dis. 2016;52(1):359-371. doi: 10.3233/JAD-151105.

Activation of p53 in Down Syndrome and in the Ts65Dn Mouse Brain is Associated with a Pro-Apoptotic Phenotype.

Author information

1
Department of Biochemical Sciences, Sapienza University of Rome, Italy.
2
Universidad Autónoma de Chile, Instituto de Ciencias Biomédicas, Facultad de Salud, Providencia, Santiago, Chile.
3
Department of Neuropathology, University of Amsterdam (NL).
4
Sanders-Brown Center of Aging, University of Kentucky, Lexington KY, USA.
5
Department of Chemistry, University of Kentucky, Lexington KY, USA.
#
Contributed equally

Abstract

Down syndrome (DS) is the most common genetic cause of intellectual disability, resulting from trisomy of chromosome 21. The main feature of DS neuropathology includes early onset of Alzheimer's disease (AD), with deposition of senile plaques and tangles. We hypothesized that apoptosis may be activated in the presence of AD neuropathology in DS, thus we measured proteins associated with upstream and downstream pathways of p53 in the frontal cortex from DS cases with and without AD pathology and from Ts65Dn mice, at different ages. We observed increased acetylation and phosphorylation of p53, coupled to reduced MDM2/p53 complex level and lower levels of SIRT1. Activation of p53 was associated with a number of targets (BAX, PARP1, caspase-3, p21, heat shock proteins, and PGC1α) that were modulated in both DS and DS/AD compared with age-matched controls. In particular, the most relevant changes (increased p-p53 and acetyl-p53 and reduced formation of MDM2/p53 complex) were found to be modified only in the presence of AD pathology in DS. In addition, a similar pattern of alterations in the p53 pathway was found in Ts65Dn mice. These results suggest that p53 may integrate different signals, which can result in a pro-apoptotic-phenotype contributing to AD neuropathology in people with DS.

KEYWORDS:

Apoptosis; Ts65Dn mouse model; caspase; p53; sirtuins; trisomy 21

PMID:
26967221
PMCID:
PMC4968087
DOI:
10.3233/JAD-151105
[Indexed for MEDLINE]
Free PMC Article

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