Publications (21) View all
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Dataset: Temporal Changes of Post Synaptic Signaling Molecules, Post Synaptic Density-95 and Neuronal Nitric Oxide Synthase, in the Inner Molecular Layer of the Mouse Dentate Gyrus during Voluntary Running
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Article: Aβ₁₋₄₂-RAGE interaction disrupts tight junctions of the blood-brain barrier via Ca²⁺-calcineurin signaling.
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ABSTRACT: The blood-brain barrier (BBB), which is formed by adherens and tight junctions (TJs) of endothelial cells, maintains homeostasis of the brain. Disrupted intracellular Ca²⁺ homeostasis and breakdown of the BBB have been implicated in the pathogenesis of Alzheimer's disease (AD). The receptor for advanced glycation end products (RAGE) is known to interact with amyloid β-peptide (Aβ) and mediate Aβ transport across the BBB, contributing to the deposition of Aβ in the brain. However, molecular mechanisms underlying Aβ-RAGE interaction-induced alterations in the BBB have not been identified. We found that Aβ₁₋₄₂ induces enhanced permeability, disruption of zonula occludin-1 (ZO-1) expression in the plasma membrane, and increased intracellular calcium and matrix metalloproteinase (MMP) secretion in cultured endothelial cells. Neutralizing antibodies against RAGE and inhibitors of calcineurin and MMPs prevented Aβ₁₋₄₂-induced changes in ZO-1, suggesting that Aβ-RAGE interactions alter TJ proteins through the Ca²⁺-calcineurin pathway. Consistent with these in vitro findings, we found disrupted microvessels near Aβ plaque-deposited areas, elevated RAGE expression, and enhanced MMP secretion in microvessels of the brains of 5XFAD mice, an animal model for AD. We have identified a potential molecular pathway underlying Aβ-RAGE interaction-induced breakage of BBB integrity. This pathway might play an important role in the pathogenesis of AD.Journal of Neuroscience 06/2012; 32(26):8845-54. · 7.11 Impact Factor -
Article: Intracellular amyloid-β accumulation in calcium-binding protein-deficient neurons leads to amyloid-β plaque formation in animal model of Alzheimer's disease.
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ABSTRACT: One of the major hallmarks of Alzheimer's disease (AD) is the extracellular deposition of amyloid-β (Aβ) as senile plaques in specific brain regions. Clearly, an understanding of the cellular processes underlying Aβ deposition is a crucial issue in the field of AD research. Recent studies have found that accumulation of intraneuronal Aβ (iAβ) is associated with synaptic deficits, neuronal death, and cognitive dysfunction in AD patients. In this study, we found that Aβ deposits had several shapes and sizes, and that iAβ occurred before the formation of extracellular amyloid plaques in the subiculum of 5XFAD mice, an animal model of AD. We also observed pyroglutamate-modified Aβ (N3pE-Aβ), which has been suggested to be a seeding molecule for senile plaques, inside the Aβ plaques only after iAβ accumulation, which argues against its seeding role. In addition, we found that iAβ accumulates in calcium-binding protein (CBP)-free neurons, induces neuronal death, and then develops into senile plaques in 2-4-month-old 5XFAD mice. These findings suggest that N3pE-Aβ-independent accumulation of Aβ in CBP-free neurons might be an early process that triggers neuronal damage and senile plaque formation in AD patients. Our results provide new insights into several long-standing gaps in AD research, namely how Aβ plaques are formed, what happens to iAβ and how Aβ causes selective neuronal loss in AD patients.Journal of Alzheimer's disease: JAD 01/2012; 29(3):615-28. · 3.74 Impact Factor -
Article: RNA-Seq analysis of frontal cortex and cerebellum from 5XFAD mice at early stage of disease pathology.
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ABSTRACT: The pathogenesis of Alzheimer's disease (AD), especially the early events of AD pathology, remains unknown because of the complexity of AD and limitation of analysis methods. Transcriptome analysis has provided comprehensive insights to investigate the complex cellular activity in brain, but the transcriptome profiles from AD patients with microarray have generated discordant results. Here, for the first time, we performed transcriptome analysis of frontal cortex and cerebellum in 7-week-old 5XFAD transgenic mice (before extracellular amyloid plaque deposits) using high-throughput RNA-Seq analysis. Specific functional annotations were identified with differentially expressed genes (DEGs) of frontal cortex (a typically vulnerable region of AD pathology) and cerebellum (a typically non-vulnerable region of AD pathology). Cardiovascular disease-related genes were significantly found in down-regulated DEGs of frontal cortex, and mitochondrial dysfunction-related genes were evident in down-regulated DEGs of cerebellum. Additionally, we found RNA variants at the nucleotide level in transgenic mice compared with non-transgenic mice. Our results indicate that both frontal cortex and cerebellum in 5XFAD transgenic mice show specific pathological processes in the early pathophysiology of AD.Journal of Alzheimer's disease: JAD 01/2012; 29(4):793-808. · 3.74 Impact Factor -
Article: Gami-Chunghyuldan ameliorates memory impairment and neurodegeneration induced by intrahippocampal Aβ 1-42 oligomer injection.
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ABSTRACT: Soluble oligomeric forms of amyloid beta (AβO) are regarded as a main cause of synaptic and cognitive dysfunction in Alzheimer's disease (AD) and have been a primary target in the development of drug treatments for AD. The present study utilized a mouse model of AD induced by intrahippocampal injection of AβO (10 μM) to investigate the effects of Gami-Chunghyuldan (GCD), a standardized multi-herbal medicinal formula, on the presentation of memory deficits and neurohistological pathogenesis. GCD (10 and 50mg/kg/day, 5 days, p.o.) improved AβO-induced memory impairment as well as reduced neuronal cell death, astrogliosis, and microgliosis in the hippocampus. In addition, GCD prevented AβO-triggered synaptic disruption and cholinergic fiber loss. These results suggest that GCD may be useful in the prevention and treatment of AD.Neurobiology of Learning and Memory 06/2011; 96(2):306-14. · 3.42 Impact Factor
