New mouse model of Alzheimer's.
Ontology highlight
ABSTRACT:
SUBMITTER: Nilsson P
PROVIDER: S-EPMC4102956 | biostudies-other | 2014 Jul
REPOSITORIES: biostudies-other
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Project description:Extracellular aggregates of amyloid ? (A?) peptides, which are characteristic of Alzheimer's disease (AD), act as an essential trigger for glial cell activation and the release of ATP, leading to the stimulation of purinergic receptors, especially the P2X7 receptor (P2X7R). However, the involvement of P2X7R in the development of AD is still ill-defined regarding the dual properties of this receptor. Particularly, P2X7R activates the NLRP3 inflammasome leading to the release of the pro-inflammatory cytokine, IL-1?; however, P2X7R also induces cleavage of the amyloid precursor protein generating A? peptides or the neuroprotective fragment sAPP?. We thus explored in detail the functions of P2X7R in AD transgenic mice. Here, we show that P2X7R deficiency reduced A? lesions, rescued cognitive deficits and improved synaptic plasticity in AD mice. However, the lack of P2X7R did not significantly affect the release of IL-1? or the levels of non-amyloidogenic fragment, sAPP?, in AD mice. Instead, our results show that P2X7R plays a critical role in A? peptide-mediated release of chemokines, particularly CCL3, which is associated with pathogenic CD8+ T cell recruitment. In conclusion, our study highlights a novel detrimental function of P2X7R in chemokine release and supports the notion that P2X7R may be a promising therapeutic target for AD.
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Project description:BackgroundTransgenic mice expressing mutated amyloid precursor protein (APP) and presenilin (PS)-1 or -2 have been successfully used to model cerebral beta-amyloidosis, one of the characteristic hallmarks of Alzheimer's disease (AD) pathology. However, the use of many transgenic lines is limited by premature death, low breeding efficiencies and late onset and high inter-animal variability of the pathology, creating a need for improved animal models. Here we describe the detailed characterization of a new homozygous double-transgenic mouse line that addresses most of these issues.Methodology/principal findingsThe transgenic mouse line (ARTE10) was generated by co-integration of two transgenes carrying the K670N/M671L mutated amyloid precursor protein (APP(swe)) and the M146V mutated presenilin 1 (PS1) both under control of a neuron-specific promoter. Mice, hemi- as well as homozygous for both transgenes, are viable and fertile with good breeding capabilities and a low rate of premature death. They develop robust AD-like cerebral beta-amyloid plaque pathology with glial inflammation, signs of neuritic dystrophy and cerebral amyloid angiopathy. Using our novel image analysis algorithm for semi-automatic quantification of plaque burden, we demonstrate an early onset and progressive plaque deposition starting at 3 months of age in homozygous mice with low inter-animal variability and 100%-penetrance of the phenotype. The plaques are readily detected in vivo by PiB, the standard human PET tracer for AD. In addition, ARTE10 mice display early loss of synaptic markers and age-related cognitive deficits. By applying a gamma-secretase inhibitor we show a dose dependent reduction of soluble amyloid beta levels in the brain.ConclusionsARTE10 mice develop a cerebral beta-amyloidosis closely resembling the beta-amyloid-related aspects of human AD neuropathology. Unifying several advantages of previous transgenic models, this line particularly qualifies for the use in target validation and for evaluating potential diagnostic or therapeutic agents targeting the amyloid pathology of AD.
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Project description:To identify molecular pathological alterations in AD brains, we performed interspecies comparative microarray analyses using RNAs prepared from postmortem human brain tissues donated for the Hisayama study and hippocampal RNAs from the triple-transgenic mouse model of AD (3xTg-AD) Three-way ANOVA of microarray data from frontal cortex, temporal cortex and hippocampus with presence/absence of AD and vascular dementia, and sex, as factors revealed that the gene expression profile is most significantly altered in the hippocampi of AD brains. Comparative analyses of the brains of AD patients and a mouse model of AD showed that genes involved in non-insulin dependent DM and obesity were significantly altered in both, as were genes related to psychiatric disorders and AlzheimerM-bM-^@M-^Ys disease. 3xTg-AD-H mice harboring a homozygous Psen1M146V mutation and homozygous mutant transgenes for APPSwe and tauP301L, 3xTg-AD-h mice harboring hemizygous APPSwe and tauP301L transgenes with a homozygous Psen1M146V mutation, and non-transgenic control mice (non-Tg) were used in this study, (male, n=3 for each group). RNA samples prepared from hippocampi were subjected to microarray analysis using the Affymetrix Mouse Gene 1.0 ST platform (GPL6246).
2013-04-17 | E-GEOD-36981 | biostudies-arrayexpress
Project description:To identify molecular pathological alterations in AD brains, we performed interspecies comparative microarray analyses using RNAs prepared from postmortem human brain tissues donated for the Hisayama study and hippocampal RNAs from the triple-transgenic mouse model of AD (3xTg-AD) Three-way ANOVA of microarray data from frontal cortex, temporal cortex and hippocampus with presence/absence of AD and vascular dementia, and sex, as factors revealed that the gene expression profile is most significantly altered in the hippocampi of AD brains. Comparative analyses of the brains of AD patients and a mouse model of AD showed that genes involved in non-insulin dependent DM and obesity were significantly altered in both, as were genes related to psychiatric disorders and Alzheimer’s disease.
2013-04-17 | GSE36981 | GEO
Project description:Alzheimer's disease (AD) is a progressive disorder characterized by a variety of molecular pathologies causing cortical dementia with a prominent memory deficit. Formation of the pathology, which begins decades before the diagnosis of the disease, is highly correlated with the clinical symptoms. Several proteomics studies were performed using animal models to monitor the alterations of the brain tissue proteome at different stages of AD. However, proteome changes in the brain regions of newborn transgenic mouse model have not been investigated yet. To this end, we analyzed protein expression alterations in cortex, hippocampus and cerebellum of transgenic mice carrying five familial AD mutations (5XFAD) at neonatal day-1. Our results indicate a remarkable difference in protein expression profile of newborn 5XFAD brain with region specific variations. Additionally, the proteins, which show similar expression alteration pattern in postmortem human AD brains, were determined. Bioinformatics analysis showed that the molecular alterations were mostly related to the cell morphology, cellular assembly and organization, and neuroinflammation. Moreover, morphological analysis revealed that there is an increase in neurite number of 5XFAD mouse neurons in vitro. We suggest that, molecular alterations in the AD brain exist even at birth, and perhaps the disease is silenced until older ages when the brain becomes vulnerable.
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Project description:Mitochondrial dysfunction has been proposed to play a pivotal role in neurodegenerative diseases, including Alzheimer's disease (AD). To address whether mitochondrial dysfunction precedes the development of AD pathology, we conducted mitochondrial functional analyses in female triple transgenic Alzheimer's mice (3xTg-AD) and age-matched nontransgenic (nonTg). Mitochondrial dysfunction in the 3xTg-AD brain was evidenced by decreased mitochondrial respiration and decreased pyruvate dehydrogenase (PDH) protein level and activity as early as 3 months of age. 3xTg-AD mice also exhibited increased oxidative stress as manifested by increased hydrogen peroxide production and lipid peroxidation. Mitochondrial amyloid beta (Abeta) level in the 3xTg-AD mice was significantly increased at 9 months and temporally correlated with increased level of Abeta binding to alcohol dehydrogenase (ABAD). Embryonic neurons derived from 3xTg-AD mouse hippocampus exhibited significantly decreased mitochondrial respiration and increased glycolysis. Results of these analyses indicate that compromised mitochondrial function is evident in embryonic hippocampal neurons, continues unabated in females throughout the reproductive period, and is exacerbated during reproductive senescence. In nontransgenic control mice, oxidative stress was coincident with reproductive senescence and accompanied by a significant decline in mitochondrial function. Reproductive senescence in the 3xTg-AD mouse brain markedly exacerbated mitochondrial dysfunction. Collectively, the data indicate significant mitochondrial dysfunction occurs early in AD pathogenesis in a female AD mouse model. Mitochondrial dysfunction provides a plausible mechanistic rationale for the hypometabolism in brain that precedes AD diagnosis and suggests therapeutic targets for prevention of AD.
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