Prion infection of mice transgenic for human APPSwe: increased accumulation of cortical formic acid extractable Abeta(1-42) and rapid scrapie disease development.
ABSTRACT Neuropathological, epidemiological and experimental data indicate a potential interrelationship between Alzheimer's disease and prion diseases. Proteolytic processing of amyloid precursor protein (APP) by beta-secretase was recently suggested to be controlled by prion protein expression. Here, we characterized the prion infection of Tg2576 mice, which overexpress the human APP(Swe) protein. Prion infection of Tg2576-mice led to an early death of the animals, which was preceded by a relatively short symptomatic stage. However, disease-associated gliosis and deposition of misfolded prion protein PrP(Sc) were identical in infected Tg2576-mice and non-transgenic littermate controls. To analyze the effect of prion infection on APP processing and generation of beta-amyloid we determined cortical levels of SDS- and formic acid (FA)-extractable forms of beta-amyloid (1-40) and (1-42) by ELISA. Formic acid-extractable Abeta (1-42) levels were 10-fold higher in infected versus uninfected Tg2576 mice whereas other forms of Abeta were essentially unaffected by the prion infection. Hence, the experimental model demonstrates that a prion infection of the CNS promotes selectively formation of FA-extractable Abeta(1-42) in Tg2576 mice.
- SourceAvailable from: José Antonio del RíoNeurobiology of aging 01/2013; · 4.85 Impact Factor
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ABSTRACT: Alzheimer's disease and prion pathologies (e.g., Creutzfeldt-Jakob disease (CJD)) display profound neural lesions associated with aberrant protein processing and extracellular amyloid deposits. Dab1 has been implicated in the regulation of amyloid precursor protein (APP), but a direct link between human prion diseases and Dab1/APP interactions has not been published. Here we examined this putative relationship in 17 cases of sporadic CJD (sCJD) post-mortem. Biochemical analyses of brain tissue revealed two groups, which also correlated with PrP(sc) types 1 and 2. One group with PrP(sc) type 1 showed increased Dab1 phosphorylation and lower betaCTF production with an absence of Abeta deposition. The second sCJD group, which carried PrP(sc) type 2, showed lower levels of Dab1 phosphorylation and betaCTF production, and Abeta deposition. Thus, the present observations suggest a correlation between Dab1 phosphorylation, Abeta deposition and PrP(sc) type in sCJD.Neurobiology of Disease 10/2009; 37(2):324-9. DOI:10.1016/j.nbd.2009.10.010 · 5.20 Impact Factor
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ABSTRACT: In Transmissible Spongiform Encephalopathies (TSEs) and Alzheimer disease (AD) both misfolding and aggregation of specific proteins represent key features. Recently, it was observed that PrP (c) is a mediator of a synaptic dysfunction induced by Aβ oligomers. We tested a novel γ secretase modulator (CHF5074) in a murine model of prion disease. Groups of female mice were intracerebrally or intraperitoneally infected with the mouse-adapted Rocky Mountain Laboratory prions. Two weeks prior infection, the animals were provided with a CHF5074-medicated diet (375 ppm) or a standard diet (vehicle) until they showed neurological signs and eventually died. In intracerebrally infected mice, oral administration of CHF5074 did not prolong survival of the animals. In intraperitoneally-infected mice, CHF5074-treated animals showed a median survival time of 21 days longer than vehicle-treated mice (p < 0.001). In these animals, immunohistochemistry analyses showed that deposition of PrP (Sc) in the cerebellum, hippocampus and parietal cortex in CHF5074-treated mice was significantly lower than in vehicle-treated animals. Immunostaining of glial fibrillary acidic protein (GFAP) in parietal cortex revealed a significantly higher reactive gliosis in CHF5074-treated mice compared to the control group of infected animals. Although the mechanism underlying the beneficial effects of CHF5074 in this murine model of human prion disease is unclear, it could be hypothesized that the drug counteracts PrP (Sc ) toxicity through astrocyte-mediated neuroprotection. CHF5074 shows a pharmacological potential in murine models of both AD and TSEs thus suggesting a link between these degenerative pathologies.Prion 01/2012; 6(1):62-72. DOI:10.4161/pri.6.1.18317 · 1.97 Impact Factor