• 통합자연과학논문집
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• 제6권3호
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• pp.125-137
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• 2013

Promising evidence suggests that amyloid beta peptide ($A{\beta}$), a key mediator in age-dependent neuronal and cerebrovascular degeneration, activates death signalling processes leading to neuronal as well as non-neuronal cell death in the central nervous system. A major cellular event in $A{\beta}$-induced apoptosis of non-neuronal cells, including cerebral endothelial cells, astrocytes and oligodendrocytes, is mitochondrial dysfunction. The apoptosis signalling cascade upstream of mitochondria entails $A{\beta}$ activation of neutral sphingomyelinase, resulting in the release of ceramide from membrane sphingomyelin. Ceramide then activates protein phosphatase 2A (PP2A), a member in the ceramide-activated protein phosphatase (CAPP) family. PP2A dephosphorylation of Akt and FKHRL1 plays a pivotal role in $A{\beta}$-induced Bad translocation to mitochondria and transactivation of Bim. Bad and Bim are pro-apoptotic proteins that cause mitochondrial dysfunction characterized by excessive ROS formation, mitochondrial DNA (mtDNA) damage, and release of mitochondrial apoptotic proteins including cytochrome c, apoptosis inducing factor (AIF), endonuclease G and Smac. The cellular events activated by $A{\beta}$ to induce death of non-neuronal cells are complex. Understanding these apoptosis signalling processes will aid in the development of more effective strategies to slow down age-dependent cerebrovascular degeneration caused by progressive cerebrovascular $A{\beta}$ deposition.

• Biomolecules & Therapeutics
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• 제14권2호
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• pp.96-101
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• 2006

Amyloid$\beta(A{\beta})$ has been reported have an effect on the induction of oxidative stress that involves the functional and structural abnormalities in Alzheimer's disease. As a role of a radical scavenger, a green tea treatment was found have some inhibitory effect on the neurodegenerative process. The aim of this study was to determine if green tea catechin (GTC) reduces in transgenic model. To test this, transgenic mice carrying neuronspecific enolase (NSE) controlled C-terminus (105) of APP (APP-C105) were created and treated them with a low ana high dose of GTC for 6 months. Herein, we conclude that transgenic mice expressing NSE/APP-C105 were successfully created and the GTC-treated group exhibited significant reduction in body weight. Thus, GTC might be a good prevention of obesity or good treatment for AD patient.

• 대한본초학회지
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• 제34권4호
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• pp.9-18
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• 2019

Objectives : It has been known to be correlated between phlegm and dementia from the perspective of oriental medicine, but it is unexplored whether herbal medicines to treat phlegm have pharmacological actions on Alzheimer's disease (AD). The aim of this study was to evaluate and to compare effects of herbal medicines to treat phlegm against AD in vitro. Methods : We selected 11 herbal medicines which treat phlegm and obtained each extract by boiling in 10-fold distilled water for 2 h. And we performed the assay of acetylcholinesterase (AChE) inhibitory effects of 11 herbal extracts. Next, we evaluated neuroprotective effects of them against amyloid $beta_{25-35}$ ($A{\beta}_{25-35}$) plaque-induced toxicity in HT22 mouse hippocampal neuronal cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. To investigate whether they show the anti-inflammatory effects against lipopolysaccharide (LPS), we also measured the levels of nitric oxide (NO) in BV2 microglia cells using griess reagent assay. Results : We found that Gamiyeongsin-hwan (GYH) and Cheonghunhwadam-tang (CHT) exhibited remarkable AChE inhibitory effects. In HT22 cells, Arisaematis Rhizoma, Trichosanthis Semen and Fritillariae Thunbergii Bulbus suppressed $A{\beta}_{25-35}$ plaque-induced neuronal cell death. In BV2 cells, Cheongung-hwan significantly inhibited the increase of NO contents induced by LPS and GYH and CHT showed a tendency to inhibit LPS-induced NO generation. Conclusions : These results suggest that several herbal medicines to treat phlegm showed the significant effects on AChE inhibition, neuroprotection against $A{\beta}_{25-35}$ plaque-induced toxicity, and inhibition of NO generation. Therefore, we demonstrate the possibility that herbal medicines with treating phlegm has effects against AD.

• 동의신경정신과학회지
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• 제19권3호
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• pp.179-193
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• 2008

Objective: The antioxidant and anti-Alzheimer effects of Semen Ziziphi Spinosae (SZS) water extract against the amyloid beta peptide (1-42) or H202-induced oxidative damage and cell death were investigated in rat pheochromocytoma line PC 12. Methods: The cells were incubated with SZS water extract and oxidative damage-inducing materials, amyloid beta peptide (1-42) or H2O2 for 24 h. The cellular viability was assessed by WST-1 assay, cytotoxic damage by LDH activity assay, oxidative damages of cells by fluorescence spectrophotometric method, and apoptosis by TUNEL staining assay. Results and Conclusions: 1. Preincubation of the cells with SZS water extract prior to amyloid beta peptide (1-42) (2 uM) or H2O2 (30 uM) exposure elevated the cell survival close to the control and decreased the level of LDH activity and the fluorescence from the cell homogenates and TUNEL staining of the cells, compared to only amyloid beta peptide (1-42) (2 uM) or H2O2 (30 uM) treated conditions. 2. Our study suggests that Semen Ziziphi Spinosae (SZS) water extract has protective effects against amyloid beta peptide (1-42) or H2O2-induced cell toxicity through the antioxidation mechanism, which might be beneficial for the treatment of Alzheimer's disease.

• BMB Reports
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• 제50권7호
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• pp.345-354
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• 2017

Autophagy, a catabolic process necessary for the maintenance of intracellular homeostasis, has recently been the focus of numerous human diseases and conditions, such as aging, cancer, development, immunity, longevity, and neurodegeneration. However, the continued presence of autophagy is essential for cell survival and dysfunctional autophagy is thought to speed up the progression of neurodegeneration. The actual molecular mechanism behind the progression of dysfunctional autophagy is not yet fully understood. Emerging evidence suggests that basal autophagy is necessary for the removal of misfolded, aggregated proteins and damaged cellular organelles through lysosomal mediated degradation. Physiologically, neurodegenerative disorders are related to the accumulation of amyloid ${\beta}$ peptide and ${\alpha}-synuclein$ protein aggregation, as seen in patients with Alzheimer's disease and Parkinson's disease, respectively. Even though autophagy could impact several facets of human biology and disease, it generally functions as a clearance for toxic proteins in the brain, which contributes novel insight into the pathophysiological understanding of neurodegenerative disorders. In particular, several studies demonstrate that natural compounds or small molecule autophagy enhancer stimuli are essential in the clearance of amyloid ${\beta}$ and ${\alpha}-synuclein$ deposits. Therefore, this review briefly deliberates on the recent implications of autophagy in neurodegenerative disorder control, and emphasizes the opportunities and potential therapeutic application of applied autophagy.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2283-2287
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• 2007

Amyloid fibril formation of amyloid β/A4 protein (Aβ) is critical to understand the pathological mechanism of Alzheimer's disease and develop controlling strategy toward the neurodegenerative disease. For this purpose, dequalinium (DQ) has been employed as a specific modifier for Aβ aggregation and its subsequent cytotoxicity. In the presence of DQ, the final thioflavin-T binding fluorescence of Aβ aggregates decreased significantly. It was the altered morphology of Aβ aggregates in a form of the bundles of the fibrils, distinctive from normal single-stranded amyloid fibrils, and the resulting reduced β-sheet content that were responsible for the decreased fluorescence. The morphological transition of Aβ aggregates assessed with atomic force microscope indicated that the bundle structure observed with DQ appeared to be resulted from the initial multimeric seed structure rather than lateral association of preformed single-stranded fibrils. Investigation of the seeding effect of the DQ-induced Aβ aggregates clearly demonstrated that the seed structure has determined the final morphology of Aβ aggregates as well as the aggregative kinetics by shortening the lag phase. In addition, the cytotoxicity was also varied depending on the final morphology of the aggregates. Taken together, DQ has been considered to be a useful chemical probe to control the cytotoxicity of the amyloid fibrils by influencing the seed structures which turned out to be central to develop therapeutic strategy by inducing the amyloid fibrils in different shapes with varied toxicities.

• Journal of Ginseng Research
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• 제40권3호
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• pp.278-284
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• 2016

Background: The ginsenoside Rb1 (Rb1) is the most abundant compound in the root of Panax ginseng. Recent studies have shown that Rb1 has a neuroprotective effect. However, the mechanisms underlying this effect are still unknown. Methods: We used stable isotope labeling with amino acids in cell culture, combined with quantitative mass spectrometry, to explore a potential protective mechanism of Rb1 in ${\beta}$-amyloid-treated neuronal cells. Results: A total of 1,231 proteins were commonly identified from three replicate experiments. Among these, 40 proteins were significantly changed in response to Rb1 pretreatment in ${\beta}$-amyloid-treated neuronal cells. Analysis of the functional enrichments and protein interactions of altered proteins revealed that actin cytoskeleton proteins might be linked to the regulatory mechanisms of Rb1. The CAP1, CAPZB, TOMM40, and DSTN proteins showed potential as molecular target proteins for the functional contribution of Rb1 in Alzheimer's disease (AD). Conclusion: Our proteomic data may provide new insights into the protective mechanisms of Rb1 in AD.

• Biomolecules & Therapeutics
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• 제22권3호
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• pp.232-238
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• 2014

Alzheimer's disease (AD) is the most common neurodegenerative disease without known ways to cure. A key neuropathologic manifestation of the disease is extracellular deposition of beta-amyloid peptide (Ab). Specific mechanisms underlying the development of the disease have not yet been fully understood. In this study, we investigated effects of 4-O-methylhonokiol on memory dysfunction in APP/PS1 double transgenic mice. 4-O-methylhonokiol (1 mg/kg for 3 month) significantly reduced deficit in learning and memory of the transgenic mice, as determined by the Morris water maze test and step-through passive avoidance test. Our biochemical analysis suggested that 4-O-methylhonokiol ameliorated $A{\beta}$ accumulation in the cortex and hippocampus via reduction in beta-site APP-cleaving enzyme 1 expression. In addition, 4-O-methylhonokiol attenuated lipid peroxidation and elevated glutathione peroxidase activity in the double transgenic mice brains. Thus, suppressive effects of 4-O-methylhonokiol on $A{\beta}$ generation and oxidative stress in the brains of transgenic mice may be responsible for the enhancement in cognitive function. These results suggest that the natural compound has potential to intervene memory deficit and progressive neurodegeneration in AD patients.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1503-1507
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• 2013

The two major symptoms characterizing Alzheimer's disease are the formation of amyloid-${\beta}$ extracellular deposits in the form of senile plaques and intracellular neurofibrillary tangles (NFTs) that consist of pathological hyperphosphorylated tau protein aggregated into insoluble paired helical filaments (PHFs). Neurons of the central nervous system have appreciable amounts of tau protein, a microtubule-associated protein. To maintain an optimal operation of nerves, the microtubules are stabilized, which is necessary to support cell structure and cellular processes. When the modified tau protein becomes dysfunctional, the cells containing misfolded tau cannot maintain cell structure. One of the pathological hallmarks of Alzheimer's disease is hyperphosphorylated tau protein. This paper shows that the small heat shock protein from humans (Hsp27) reduces hyperphosphorylated tau and prevents hyperphosphorylated tau-induced cell death of the human neuroblastoma cell line SH-SY5Y.

• 통합자연과학논문집
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• 제7권2호
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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.