ABSTRACT
Alzheimer's disease is a progressive neurodegenerative disorder characterized by impairments in synaptic plasticity and cognitive performance. Current treatments are unable to achieve satisfactory therapeutic effects or reverse the progression of the disease. Calcineurin has been implicated as part of a critical signaling pathway for learning and memory, and neuronal calcineurin may be hyperactivated in AD. To investigate the effects and underlying mechanisms of FK506, a calcineurin inhibitor, on Alzheimer-like behavior and synaptic dysfunction in the 3 × Tg-AD transgenic mouse model of Alzheimer's disease, we investigated the effect of FK506 on cognitive function and synaptic plasticity in the 3 × Tg-AD transgenic mouse model of Alzheimer's disease. The results showed that FK506 treatment ameliorated cognitive deficits, as indicated by the decreased latency in the water maze, and attenuated tau hyperphosphorylation in 3 × Tg-AD mice. Treatment with FK506 also reduced the levels of certain markers of postsynaptic deficits, including PSD-95 and NR2B, and reversed the long-term potentiation deficiency and dendritic spine impairments in 3 × Tg-AD mice. These findings suggest that treatment with calcineurin inhibitors such as FK506 can be an effective therapeutic strategy to rescue synaptic deficit and cognitive impairment in familial Alzheimer's disease and related tauopathies.
Subject(s)
Alzheimer Disease , Calcineurin Inhibitors , Disease Models, Animal , Mice, Transgenic , Tacrolimus , Animals , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Alzheimer Disease/physiopathology , Tacrolimus/pharmacology , Calcineurin Inhibitors/pharmacology , Mice , Maze Learning/drug effects , Maze Learning/physiology , Calcineurin/metabolism , Neuronal Plasticity/drug effects , Neuronal Plasticity/physiology , tau Proteins/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Male , Synapses/drug effects , Synapses/metabolism , Disks Large Homolog 4 Protein/metabolismABSTRACT
Neurogenesis plays a role in hippocampus-dependent learning and impaired neurogenesis may correlate with cognitive deficits in Alzheimer's disease. Spatial training influences the production and fate of newborn cells in hippocampus of normal animals, whereas the effects on neurogenesis in Alzheimer-like animal are not reported until now. Here, for the first time, we investigated the effect of Morris water maze training on proliferation, survival, apoptosis, migration, and differentiation of newborn cells in ß-amyloid-treated Alzheimer-like rats. We found that spatial training could preserve a short-term survival of newborn cells generated before training, during the early phase, and the late phase of training. However, the training had no effect on the long-term survival of mature newborn cells generated at previously mentioned 3 different phases. We also demonstrated that spatial training promoted newborn cell differentiation preferentially to the neuron direction. These findings suggest a time-independent neurogenesis induced by spatial training, which may be indicative for the cognitive stimulation in Alzheimer's disease therapy.
Subject(s)
Alzheimer Disease/pathology , Alzheimer Disease/psychology , Amyloid beta-Peptides/administration & dosage , Cell Differentiation , Cognition/physiology , Hippocampus/cytology , Maze Learning/physiology , Neurogenesis/physiology , Peptide Fragments/administration & dosage , Spatial Navigation/physiology , Animals , Cell Survival , Disease Models, Animal , Hippocampus/physiology , Male , Rats, Sprague-Dawley , Time FactorsABSTRACT
PURPOSE: MicroRNA-323 (miR-323) has been reported to be upregulated in Ischemia/Reperfusion (I/R) injury-treated neuronal cell. However, the effect and underlying mechanism of miR-323 in I/R-induced neuronal cell death remains poorly understood. The current study was aim to investigate the role and molecular basis of miR-323 in I/R-induced neuronal cell. METHODS: An oxygen-glucose deprivation (OGD) model of hippocampal neuron I/R was produced in vitro. Cell apoptosis, cell survival, and the expression of miR-323 were determined after 6 h, 12 h and 24 h after OGD treatment. The up- or down-regulation of miR-323 was performed by miR-323 mimics or anti-miR-323, respectively. RESULTS: OGD induced apoptosis and suppressed survival in rat hippocampal neurons. And the expression levels of miR-323 were increased after OGD treatment. Furthermore, the up-regulation of miR-323 promoted apoptosis and suppressed survival, whereas the inhibition of miR-323 suppressed apoptosis and enhanced survival in OGD-treated neurons. Moreover, miR-323 could directly bind to BRI3 3'-UTR. Notably, the knockdown of BRI3 by BRI3 siRNA apparently abrogated cell survival and induced cell apoptosis in rat neurons. CONCLUSION: This study indicated that miR-323 might regulate ischemia/reperfusion-induced rat neuronal cell death via targeting BRI3.