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Background: Alterations in the methionine cycle and abnormal tau phosphorylation are implicated in many neurodegenerative diseases, including Alzheimer's disease and frontotemporal dementia. rTg4510 mice express mutant human P301L tau and are a model of tau hyperphosphorylation. The cognitive deficit seen in these animals correlates with a burden of hyperphosphorylated tau and is a model to test therapies aimed at lowering phosphorylated tau.Objective: This study aimed to increase protein phosphatase 2A activity through supplementation of S-adenosylmethionine and analyze the effect on spatial memory and tau in treated animals.Methods: 6-month-old rTg4510 mice were treated with 100 mg/kg S-adenosylmethionine by oral gavage for 3 weeks. Spatial recognition memory was tested in the Y-maze. Alterations to phosphorylated tau and protein phosphatase 2A were explored using immunohistochemistry, western blot, and enzyme-linked immunosorbent assays.Results: Treatment with S-adenosylmethionine increased the Y-maze novel arm exploration time and increased both the expression and activity of protein phosphatase 2A. Furthermore, treatment reduced the number of AT8 positive neurons and reduced the expression of phosphorylated tau (Ser202/Thr205). S-adenosylmethionine contributes to multiple pathways in neuronal homeostasis and neurodegeneration.Conclusion: This study shows that supplementation with S-adenosylmethionine stabilizes the heterotrimeric form of PP2A resulting in an increase the enzymatic activity, a reduced level of pathological tau, and improved cognition. [ABSTRACT FROM AUTHOR]

Over the past 100 years, there has been an exponential increase in our understanding of the underlying pathology of Alzheimer's disease (AD). This growth in knowledge has largely stemmed from the intensification of research into AD which has occurred over the past three decades and the incorporation of the amyloid cascade hypothesis as the generally accepted dogma of AD pathogenesis. While at times contentious, the notion that AD arises from aberrations in amyloid-β (Aβ) production and degradation has led to a number of significant breakthroughs in the way in which AD is currently diagnosed and in the attempts at disease modifying therapies, from investigations into the underlying factors mediating the aggregation of Aβ to the development of therapeutic strategies and measures of neuroimaging allowing Aβ burden to be monitored within the AD-affected brain. This review focuses on some of the recent work we have conducted toward elucidating the role of Aβ in AD. [ABSTRACT FROM AUTHOR]

A bis (thiosemicarbazonato) complex radiolabeled with positron emitting Cu-64 can be used for a new and alternative method for the non-invasive diagnosis of Alzheimer's disease using positron emission tomography (PET). Most imaging agents being investigated for the diagnosis of Alzheimer's disease target amyloid-beta plaque burden but our new approach highlights altered copper homeostasis. This approach has the potential to offer complementary information to other diagnostic procedures that elucidate plaque burden. [ABSTRACT FROM AUTHOR]