PTK2B/Pyk2 overexpression improves a mouse model of Alzheimer's disease
Résumé
Pyk2 is a Ca 2+-activated non-receptor tyrosine kinase enriched in forebrain neurons and involved in synaptic regulation. Human genetic studies associated PTK2B, the gene coding Pyk2, with risk for Alzheimer's disease (AD). We previously showed that Pyk2 is important for hippocampal function, plasticity, and spine structure. However, its potential role in AD is unknown. To address this question we used human brain samples and 5XFAD mice, an amyloid mouse model of AD expressing mutated human amyloid precursor protein and presenilin1. In the hippocampus of 5XFAD mice and in human AD patients' cortex and hippocampus, Pyk2 total levels were normal. However, Pyk2 Tyr-402 phosphorylation levels, reflecting its autophosphorylation-dependent activity, were reduced in 5XFAD mice at 8 months of age but not 3 months. We crossed these mice with Pyk2 −/− mice to generate 5XFAD animals devoid of Pyk2. At 8 months the phenotype of 5XFAD x Pyk2 −/− double mutant mice was not different from that of 5XFAD. In contrast, overexpression of Pyk2 in the hippocampus of 5XFAD mice, using adeno-associated virus, rescued autophosphorylated Pyk2 levels and improved synaptic markers and performance in several behavioral tasks. Both Pyk2 −/− and 5XFAD mice showed an increase of potentially neurotoxic Src cleavage product, which was rescued by Pyk2 overexpression. Manipulating Pyk2 levels had only minor effects on Aβ plaques, which were slightly decreased in hippocampus CA3 region of double mutant mice and increased following overexpression. Our results show that Pyk2 is not essential for the pathogenic effects of human amyloidogenic mutations in the 5XFAD mouse model. However, the slight decrease in plaque number observed in these mice in the absence of Pyk2 and their increase following Pyk2 overexpression suggest a contribution of this kinase in plaque formation. Importantly, a decreased function of Pyk2 was observed in 5XFAD mice, indicated by its decreased autophosphorylation and associated Src alterations. Overcoming this deficit by Pyk2 overexpression improved the behavioral and molecular phenotype of 5XFAD mice. Thus, our results in a mouse model of AD suggest that Pyk2 impairment may play a role in the symptoms of the disease.
Mots clés
long term potentiation
mGluR5
metabotropic glutamate receptor 5
NIH
National Institute of Health
NMDA
N-methyl-D-aspartate
PLA
proximity ligation assay
PrPc
cellular prion protein
PSD-95
95 kDa
PTK2B
protein tyrosine kinase 2B
Pyk2
proline-rich tyrosine kinase 2
SDS
sodium dodecyl sulfate
SEM
standard error of the mean
SFK
Src-family kinase
STEP
striatal enriched phosphatase
STM
short term memory
WT
Alzheimer's disease Mouse model Non-receptor tyrosine protein kinase Pyk2 Src 5XFAD
mice transgenic for human APP and presenilin1 with 5 mutations found in familial Alzheimer's disease AAV
adeno-associated virus Aβ
amyloid β AD
Alzheimer's disease ANOVA
analysis of variance APP
amyloid precursor protein CA1/3
cornu Ammoni 1/3 DAPI 4′
6-diamidine-2′-phenylindole DG
dentate gyrus FAK
focal adhesion kinase GFAP
glial fibrillary acidic protein GFP
green fluorescent protein IB
immunoblotting IF
immunofluorescence Inserm
LTM
long term memory LTP
long term potentiation mGluR5
metabotropic glutamate receptor 5 NIH
National Institute of Health NMDA
N-methyl-D-aspartate PLA
proximity ligation assay PrPc
cellular prion protein PSD-95
post-synaptic density protein
95 kDa PTK2B
protein tyrosine kinase 2B Pyk2
proline-rich tyrosine kinase 2 SDS
sodium dodecyl sulfate SEM
standard error of the mean SFK
Src-family kinase STEP
striatal enriched phosphatase STM
short term memory WT
wild type
mice transgenic for human APP and presenilin1 with 5 mutations found in familial Alzheimer's disease
AAV
adeno-associated virus
Aβ
amyloid β
AD
Alzheimer's disease
ANOVA
analysis of variance
APP
amyloid precursor protein
CA1/3
cornu Ammoni 1/3
DAPI 4′
6-diamidine-2′-phenylindole
DG
dentate gyrus
FAK
focal adhesion kinase
GFAP
glial fibrillary acidic protein
GFP
green fluorescent protein
IB
immunoblotting
IF
immunofluorescence
Inserm
long term memory
LTP
Alzheimer's disease mouse model non-receptor tyrosine protein kinase Pyk2 Src
mouse model
non-receptor tyrosine protein kinase
Src
Domaines
Sciences du Vivant [q-bio]| Origine | Fichiers produits par l'(les) auteur(s) |
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