• Korean Journal of Biological Psychiatry
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• v.8 no.1
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• pp.62-70
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• 2001

Alzheimer's disease(AD) is associated with a characteristic neuropathology. The major hallmarks of AD are senile plaques (SPs) and neurofibrillary tangles(NFTs). ${\beta}$-amyloid protein($A{\beta}$) is derived from the proteolysis of amyloid precursor protein(APP) and then converted to SPs. Mature SPs produce cytotoxicity through direct toxic effects and activation of microglia and complement. NFTs are composed of paired helical filaments(PHFs) including abnormally phosphorylated form of the microtubule-associated protein(MAP) tau and increased tau level in cerebrospinal fluid may be observed in most AD. The aggregation of $A{\beta}$ and tau formation are thought to be a final common pathway of AD. Acetylcholine, dopamine, serotonin, GABA and their receptors are associated with AD. Especially, decreased nicotinic acetylcholine receptors(nAChRs) in AD are reported. Genetic lesions associated with AD are mutations in the structural genes for the APP located on chromosome 21, presenilin(PSN)1 located on chromosome 14 and PSN2 located on chromosome 1. Also, trisomy 21, Apo-E gene located on chromosome 19, PMF locus, low density lipoprotein receptor-related protein and ${\alpha}$-macroglobulin increase risk of AD. In this article, we will review about the neurobiology of AD and some newly developed research areas.

• Animal cells and systems
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• v.5 no.2
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• pp.139-143
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• 2001

Alzheimer's disease is the most common form of dementia and no cure is known so far. Extensive genetic works and in vitro experiments combined with clinical observations link amyloid $\beta$--protein (A$\beta$-) to the pathogenesis of Alzheimer's disease (AD). It was hypothesized that $A\beta$- becomes toxic when it adopts a fibrillar conformation. Recently, non-fibrillar form of $A\beta$- was observed and the potential role in the pathogenesis of AD became an interesting subject. In this study, the cytotoxicity of non-fibrillar $A\beta$- and fibrillar $A\beta$- was compared on oxidative stress, membrane damage, or nucleosome break down. Non-fibrillar $A\beta$- was not toxic in peripheral nervous system-derived cells but significantly toxic in central nervous system-derived cells while fibrillar $A\beta$- was non-selectively toxic in both cell culture. The neurotoxicity of non-fibrillar $A\beta$- was reproduced in semi-in vivo culture of mouse brain slice. In conclusion, non-fibrillar $A\beta$- could be more relevant to the selective neurodegeneration in Alzheimer's brains than fibrillar $A\beta$- and further research needs to be done for identification of the cause of AD.

• Journal of Oriental Neuropsychiatry
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• v.18 no.3
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• pp.55-82
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• 2007

Ohjective: This research investigates the effect of the DJR on Alzheimer's disease. Method: 1.The effects of the DJR extract on IL.-$1{\beta}$, IL-6, TNF-${\alpha}$, cox-2, and NOS-II mRNA of BV2 microglia cell line treated with LPS; 2. the behavior: 3. the infarction area of the hippocampus, and brain tissue injury in Alzheimer's diseased mice induced with ${\beta}$A were investigated. Result: 1. The DJR extract suppressed the expression of IL-$1{\beta}$, IL-6 and TNF-${\alpha}$ mRNA in BV2 microglia cell line treated with LPS. 2. The DJR extract suppressed the expression of IL-$1{\beta}$, IL-6, and TNF-${\alpha}$ protein production in BV2 microglia cell line treated with LPS. 3. For the DJR extract group a significant inhibitory effect on the memory deficit was shown for the mice with Alzheimer's disease induced by .${\beta}$A in the Moms water maze experiment, which measured stop-through latency, and distance movement-through latency. 4. The DJR extract suppressed the over-expression of IL-$1{\beta}$ protein, TNF-${\alpha}$ protein and CD68/CD11b, in the mice with Alzheimer's disease induced by ${\beta}$A 5. The DJR extract reduced the infarction area of hippocampus, and controlled the injury of brain tissue in the mice with Alzheimer's disease induced by ${\beta}$A. 6. The DJR extract reduced the tau protein, GFAP protein, and presenilin1/2 protein (immunohistochemistry) of hippocampus in the mice with Alzheimer's disease induced by ${\beta}$A. Conclusion: These results suggest that the DJR extract may he effective for the prevention and treatment of Alzheimer's disease. Investigation into the clinical use of the DJR extract for Alzheimer's disease of suggested for future research.

• The Korean Journal of Food And Nutrition
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• v.30 no.6
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• pp.1279-1285
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• 2017

$Amyloid-{\beta}$ protein ($A{\beta}$) is known to increase free radical production in neuronal cells, leading to cell death by oxidative stress. The purpose of this study was to evaluate the protective effects of $PineXol^{(R)}$ on $A{\beta}_{25-35}$ induced neuronal cell death. Rat pheochromocytoma (PC-12) cells were pre-treated with $100{\mu}g/mL$ of $PineXol^{(R)}$ for 2 h. The cells were exposed to single dose of $30{\mu}M$ $A{\beta}_{25-35}$ for 24 h. Cell death was assessed by a cell count kit-8 (CCK-8) assay, lactate and dehydrogenase (LDH) release assay. An Apoptotic process was analyzed by a protein expression of the Bcl-2 family using western blotting. Cell viability increased in PC-12 cells treated with both $A{\beta}_{25-35}$ and $PineXol^{(R)}$, compared to the control group. $PineXol^{(R)}$ induced a decrease of the Bcl-2 protein expression (p<0.05), while Bax and Sod1 increased (p<0.05), indicating attenuation of $A{\beta}_{25-35}$ induced apoptosis. These results suggest that $PineXol^{(R)}$ may be a good candidate for the prevention of Alzheimer's disease(AD).

• Korean Journal of Biological Psychiatry
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• v.5 no.1
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• pp.66-70
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• 1998

Apoptosis is a form of cell death in which the cells shrink and exhibit nuclear chromatin condensation and DNA fragmentation, and yet maintain membrane integrity. Many lines of evidence have shown that brain neurons are vulnerable to degeneration by apoptosis. Also it has been suggested that apoptosis is one of the mechanism contributing neuronal loss in Alzheimer's disease(AD), since the conditions in the disease($A{\beta}$ peptide, oxidative stress, low energy metabolism) are the inducers that activate apoptosis. Indeed some neurons in vulnerable regions of the AD brain show DNA damage, chromatin condensation, and apoptic bodies. Consistently, mutations in AD causative genes(Amyloid precursor protein, Presenilin-1 and Presenilin- 2) increase $A{\beta}$ $peptide_{1-42}(A{\beta}_{1-42})$ and sensitize neuronal cell to apoposis. However, several lines of evidence have shown that the location of neuronal loss and $A{\beta}$ peptide deposition is not correlated in AD brain and transgenic mice brain over-expressing $A{\beta}_{1-42}$. Taken together, these data may indicated that $A{\beta}$ peptide(and other causative factors of AD) can interact with other cellular insults or risk factors to exacerbate pathological mechansim of AD through apoptosis. Thus, this review discusses possible role and mechanism of apoptosis in AD.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2006.04a
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• pp.109-120
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• 2006

Alzheimer's disease (AD) is an age-related neurodegenerative disorder. The pathological hallmarks of AD are senile plaques and neurofibrillary tangles in the brain. Major component of senile plaques is amyloid beta peptide(A$\beta$) which is derived from amyloid precursor protein (APP). A$\beta$ is generated through the sequential cleavage of App by $\beta$ - and $\gamma$-secretases. $\beta$-secretase excises the ectodomain of APP ($\beta$-APPs) to leave a 99-amino acid long C-terminal fragment (APP-C99-CTF) in the membrane. $\gamma$-secretase then cleaves this membrane-tethered APP-CTF within the transmembrane domain, so releasing A$\beta$ peptides and APP-intracellular domain (AICD). Thus, $\beta$- and $\gamma$-secretase are regarded to perform the key steps in the pathogenesis of AD and have become important therapeutic targets in the prevention and treatment of AD. Enormous efforts have been focused to develop the amyloid beta related drug for cure of AD becuase A$\beta$ is believed to be one of the major causes of AD. since major pharmaceutical companies in world wide base compete to develop new drug for AD, we have to be careful to choose the drug target to success the tough race. In the present talk, possible drug targets based on basic research results will be discussed. These molecules should be a good target for development of new drug for AD and be less competitive to have a good shape for world wide competition.

• Molecules and Cells
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• v.27 no.6
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• pp.651-656
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• 2009

The formation of ${\beta}$-amyloid peptide ($A{\beta}$) is initiated from cleavage of amyloid precursor protein (APP) by a family of protease, ${\alpha}$-, ${\beta}$-, and ${\gamma}$-secretase. Sub W, a substrate peptide, consists of 10 amino acids, which are adjacent to the ${\beta}$-cleavage site of wild-type APP, and Sub M is Swedish mutant with double mutations on the left side of the ${\beta}$-cleavage site of APP. Sub W is a normal product of the metabolism of APP in the secretary pathway. Sub M is known to increase the efficiency of ${\beta}$-secretase activity, resulting in a more specific binding model compared to Sub W. Three-dimensional structures of Sub W and Sub M were studied by CD and NMR spectroscopy in water solution. On the basis of these structures, interaction models of ${\beta}$-secretase and substrate peptides were determined by molecular dynamics simulation. Four hydrogen bonds and one water-mediated interaction were formed in the docking models. In particular, the hydrogen bonding network of Sub M-BACE formed spread over the broad region of the active site of ${\beta}$-secretase (P5-P3'), and the side chain of P2- Asn formed a hydrogen bond specifically with the side chain of Arg235. These are more favorable to the cleavage of Sub M by ${\beta}$-secretase than Sub W. The two substrate peptides showed different tendency to bind to ${\beta}$-secretase and this information may useful for drug development to treat and prevent Alzheimer's disease.

• Journal of Integrative Natural Science
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• v.7 no.2
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• pp.79-86
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• 2014

Amyloid oligomers are believed to play important causal roles in many types of amyloid-related degenerative diseases. Many different laboratories have reported amyloid oligomers that differ in size, morphology, toxicity, and method of preparation or purification, raising the question of the structural relationships among these oligomer preparations. The structural plasticity that has been reported to occur in amyloid formed from the same protein sequence indicates that it is quite possible that different oligomer preparations may represent distinct structural variants. In view of the difficulty in determining the precise structure of amyloids, conformation- and epitope-specific antibodies may provide a facile means of classifying amyloid oligomer structures. Conformation-dependent antibodies that recognize generic epitopes that are specifically associated with distinct aggregation states of many different amyloid-forming sequences indicate that there are at least two fundamentally distinct types of amyloid oligomers: fibrillar and prefibrillar oligomers. Classification of amyloid oligomers according to their underlying structures may be a more useful and rational approach than relying on differences in size and morphology.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.327.2-327.2
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• 2002

Inflammatory as well as oxidative tissue damage has been associated with pathophysiology of Alzheimer's disease (AD), and nonsteroidal anti-inflammatory drugs have been shown to retard the progress of AD. In this study, we have investigated the molecular mechanisms underlying oxidative and inflammatory cell death induced by beta-amyloid (Abeta), a neurotoxic peptide associated with senile plaques formed in the brains of patients with AD, in cultured PC12 cells. (omitted)

• Biomolecules & Therapeutics
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• v.19 no.1
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• pp.90-96
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• 2011

Automated HPLC/SPE/HPLC coupling experiments using the Sepbox system allowed the rapid identification of four bioactive principles reducing the production of amyloid $\beta$-peptide ($A{\beta}$) from two South African plants, Euclea crispa subsp. crispa and Crinum macowanii. The structures of biologically active compounds isolated from the methanol extract of Euclea crispa subsp. crispa were assigned as 3-oxo-oleanolic acid (1) and natalenone (2) based on their NMR and MS data, while lycorine (3) and hamayne (4) were isolated from the dichloromethane-methanol (1:1) extract of Crinum macowanii. These compounds were shown to inhibit the production of $A{\beta}$ from HeLa cells stably expressing Swedish mutant form of amyloid precursor protein (APPsw).