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Activation of glycogen synthase kinase-3 (GSK-3) can cause memory deficits as seen in Alzheimer's disease, the most common age-associated dementia, but the mechanism is not understood. Here, we found that activation of GSK-3 by wortmannin or transient overexpression of wild-type GSK-3beta could suppress the induction of long-term potentiation (LTP) in rat(More)
Intracellular accumulation of the abnormally modified tau is hallmark pathology of Alzheimer's disease (AD), but the mechanism leading to tau aggregation is not fully characterized. Here, we studied the effects of tau SUMOylation on its phosphorylation, ubiquitination, and degradation. We show that tau SUMOylation induces tau hyperphosphorylation at(More)
Hyperphosphorylated tau is the major protein subunit of neurofibrillary tangles in Alzheimer's disease (AD) and related tauopathies. It is not understood, however, why the neurofibrillary tangle-containing neurons seen in the AD brains do not die of apoptosis but rather degeneration even though they are constantly awash in a proapoptotic environment. Here,(More)
Hyperphosphorylated tau is the major component of neurofibrillary tangles in Alzheimer disease (AD), and the tangle distribution largely overlaps with zinc-containing glutamatergic neurons, suggesting that zinc released in synaptic terminals may play a role in tau phosphorylation. To explore this possibility, we treated cultured hippocampal slices or(More)
It has been a puzzle why the tangle-bearing neurons in Alzheimer's disease (AD) brain do not die preferentially of apoptosis even though they are actually challenged by multiple proapoptotic factors. Recently, we have reported that phosphorylation of tau can antagonize apoptosis induced by exogenous apoptotic inducers. Amyloid-beta (Abeta), a recognized(More)
Abnormal phosphorylation of microtubule-associated protein tau plays a critical role in Alzheimer's disease (AD), together with a distinct decrease of energy metabolism in the affected brain regions. To explore the effect of acute energy crisis on tau phosphorylation and the underlying mechanisms, we incubated rat brain slices in artificial cerebrospinal(More)
The activity of protein phosphatase (PP)-2A and PP-1 decreased in the brains of Alzheimer's disease and inhibition of the phosphatases led to spatial memory deficit in rats. However, the molecular basis underlying memory impairment of the phosphatase inhibition is elusive. In the present study, we observed a selective inhibition of PP-2A and PP-1 with(More)
Acetylcholine is an important excitatory neurotransmitter, which plays a crucial role in synaptic transmission. The level of acetylcholine is decreased in the early stages of Alzheimer disease (AD), the most common neurodegenerative disease. Therefore, measurement of acetylcholine in the brain may help the clinical diagnosis of AD. However, the methods used(More)
Hyperphosphorylated microtubule-associated protein tau is the major protein component of neurofibrillary tangles in the brain of patients with Alzheimer's disease (AD). Until now, there is no effective cure to arrest this hyperphosphorylation. The present study was designed to explore the in vivo preventive effect of melatonin on Alzheimer-like tau(More)
Alzheimer's disease (AD) has multiple etiopathogenic factors, yet the definitive cause remains unclear and the therapeutic strategies have been elusive. Combination therapy, as one of the promising treatments, has been studied for years and may exert synergistic beneficial effects on AD through polytherapeutic targets. In this study, we tested the effects(More)