• Journal of Applied Biological Chemistry
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• 제66권
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• pp.408-415
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• 2023

Alzheimer's disease constitutes a large proportion of all neurodegenerative diseases and is mainly caused by excess aggregation of amyloid beta (Aβ), which results in oxidative stress, inflammation, and apoptosis in the neurons. Populus tomentiglandulosa belongs to the Salicaceae family and is widely distributed in Korea; the antioxidant activities of the extract and fractions from P. tomentiglandulosa have been demonstrated in previous studies. Specifically, the ethyl acetate (EtOAc) fraction of P. tomentiglandulosa (EtOAc-PT) shows the most powerful antioxidative activity. Therefore, the present study investigates the protective effects of EtOAc-PT against neuronal damage in Aβ_25-35-stimulated SH-SY5Y cells. EtOAc-PT restored cell viability significantly as well as inhibited the levels of reactive oxygen species and lactate dehydrogenase release compared to the Aβ_25-35-induced control group. Furthermore, the inflammation- and apoptosis-related protein expressions were investigated to demonstrate its neuroprotective mechanism. EtOAc-PT downmodulated the expressions of inducible nitric oxide synthase, cyclooxygenase-2, B-cell lymphoma 2 associated X, and B-cell lymphoma 2. Thus, the findings show that EtOAc-PT has protective effects against Aβ_25-35 by suppressing oxidative stress, inflammation, and apoptosis.

• Molecules and Cells
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• 제40권9호
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• pp.613-620
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• 2017

The most common form of senile dementia is Alzheimer's disease (AD), which is characterized by the extracellular deposition of amyloid ${\beta}-peptide$ ($A{\beta}$) plaques and the intracellular formation of neurofibrillary tangles (NFTs) in the cerebral cortex. Tau abnormalities are commonly observed in many neurodegenerative diseases including AD, Parkinson's disease, and Pick's disease. Interestingly, tau-mediated formation of NFTs in AD brains shows better correlation with cognitive impairment than $A{\beta}$ plaque accumulation; pathological tau alone is sufficient to elicit frontotemporal dementia, but it does not cause AD. A growing amount of evidence suggests that soluble $A{\beta}$ oligomers in concert with hyperphosphorylated tau (pTau) serve as the major pathogenic drivers of neurodegeneration in AD. Increased $A{\beta}$ oligomers trigger neuronal dysfunction and network alternations in learning and memory circuitry prior to clinical onset of AD, leading to cognitive decline. Furthermore, accumulated damage to mitochondria in the course of aging, which is the best-known nongenetic risk factor for AD, may collaborate with soluble $A{\beta}$ and pTau to induce synapse loss and cognitive impairment in AD. In this review, I summarize and discuss the current knowledge of the molecular and cellular biology of AD and also the mechanisms that underlie $A{\beta}-mediated$ neurodegeneration.

• Biomolecules & Therapeutics
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• 제19권2호
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• pp.181-186
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• 2011

Beta-amyloid (A${\beta}$) is considered as one of the major causes of Alzheimer's disease. This study examined the neuroprotective effects of chlorogenic acid, a naturally occurring polyphenol which is distributed widely in plants, fruits and vegetables, against A${\beta}$-induced toxicity. A${\beta}$ decreased significantly the viability of PC12 cells. This was accompanied by an increase in the intracellular calcium levels and cleaved caspase-3. In addition, A${\beta}$ induced an increase in Bax, and a decrease in Bcl-2 compared to the controls. However, a pre-treatment with chlorogenic acid rescued the PC12 cells from A${\beta}$ by attenuating the elevated intracellular calcium levels and reducing the levels of the apoptosis related proteins, including caspase-3, Bcl-2 and Bax. These results suggest that the protective effects of chlorogenic acid are, at least in parts, by attenuating the intracellular calcium influx and reducing apoptosis induced by A${\beta}$.

• 통합자연과학논문집
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• 제7권2호
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• pp.87-91
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• 2014

Amyloid beta ($A{\beta}$) peptide has been implicated in the pathogenesis of Alzheimer's disease and has been reported to induce apoptotic death in cell culture. Cysteine Proteases, a family of enzymes known as caspases, mediate cell death in many models of apoptosis. In the present study, we examined the caspase activity and cell death in $A{\beta}$-treated SHSY5Y cells, as an attempt to elucidate the relationship between the type of caspase and $A{\beta}$-induced cell death. $A{\beta}$ at 20 ${\mu}M$ induce activation of caspase-3, 8 and 9 activity, but not the caspase-1. Caspase-3, 8 and 9 were processed by Ab treatment, consistent with the activity assay. Inhibition of the caspase activities by the selective inhibitors, however, marginally affected the cell death induced by $A{\beta}$. Taken together, the results indicate that $A{\beta}$-induced cell death may be independent of caspase activity and rather, the enzymes might be activated as a result of the cell death.

• 생물정신의학
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• 제3권2호
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• pp.170-180
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• 1996

Lowered immune function in the senile dementia patients may be related to the abnormal metabolism of amyloid precursor protein(APP). To investigate the passibility of an abnormal metabolism of APP in lymphocytes and the possible role of APP in the activation of lymphocytes in senile dementia patients, immunohistochemical study of rat spleen and fluorescence activated cell sorter analysis(FACS) of human lymphocytes with the specific antigen far each lymphocyte and double fluorescent marker with antibody to APP were performed. After stimulating lymphocyte with phytohemagglutinin(PHA), APP mRNA and protein were extracted and quantitfied and the influence of ${\beta}$-amyloid protein($A{\beta}$) specific antibody on lymphocyte division was investigated. In spleen, the majority of cells showing $A{\beta}$ immunoreactivity was found in the T-sell dependent zone. FACS indicated that around 90% $CD_4(+)$ T-cells and 60% of $CD_8(+)$ T-sell were immunoreactive to $A{\beta}$ specific antibody(mAb 4G8). Northern blot analysis shows that lymphocyte APP mRNA was gradually increased to reach a maximum at 3 days after activation with lectin mitogen PHA. However, the $A{\beta}$ immunoreactivity an cell surface remained constant during stimulation with PHA, indicating that the release of APP(secreted farm of APP) might be increased. A very large increase in soluble APP secretion was observed in T-lymphocyte upon activation, but only law levels in the resting stale. Immunoblot was carried out an the protein obtained from cell lysate after stimulating lymphocyte by applying PHA to the cultured lymphocyte, and the result was that $A{\beta}$ band of immature farm under 116 KDa marker decreased as the duration of culture was increased after PHA stimulation. The monoclonal $A{\beta}$ specific(4G8) and polyclonal APP antibodies did not inhibit the [$^3H$]-thymidine uptake of mitogen-treated lymphocytes significantly, suggesting that mitogenesis can not be inhibited by specific $A{\beta}$ and polyclonal APP antibody. These results suggest that APP is expressed in T-cell and might be closely associated with the function of T-cells.

• 대한한의학회지
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• 제39권3호
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• pp.1-16
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• 2018

Objectives: The purpose of this study was to investigate the effects of 56 herbal formulae covered by the National Health Insurance Corporation (NHIC) on dementia-related biomarkers and neuronal cell changes. Methods: The 56 herbal formulae were extracted with 70% ethanol at $100^{\circ}C$ for 2 h. The antioxidant properties was measured by radical scavenging assay using ABTS+ radical. The acetylcholinesterase (AChE) activity was tested by Ellman's assay and $amyloid-{\beta}$ ($A{\beta}$) aggregation was determined using fluorescence method. To estimate the inhibitory effects of herbal formulae on neuronal cell death and inflammation using HT22 hippocampal cells and BV-2 microglia, respectively. Results: Among the 56 herbal formulae, Dangguiyukhwangtang, Banhasasimtang, Samhwangsasimtang, Cheongwiesan, Hwangryunhaedoktang, Banhabaekchulchunmatang, Jaeumganghwatang, Cheongseoikgitang, and Hoechunyanggyuksan has a significant inhibitory effects on acetylcholinesterase (AChE) activity. Doinseunggitang and Samhwangsasimtang exerted the effect on the inhibition of $amyloid-{\beta}$ ($A{\beta}$) aggregation. Additionally, 10 herbal formulae affected AChE and $A{\beta}$ aggregation revealed antioxidant activity as well as neuroprotective and anti-neuroinflammation effects in neuronal cell lines. Conclusions: 10 herbal formulae that have been shown to be effective against the major dementia markers have been shown to have antioxidant activity, neuronal cell protection and inhibition of brain inflammation. Further investigation of these herbal formulae will need to be validated in dementia animal models.

• 생약학회지
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• 제46권2호
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• pp.109-115
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• 2015

This study was investigated the radical scavenging effect and the protective activity of caffeic acid (CA) against oxidative stress. CA showed strong 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and hydroxyl radical ( OH) scavenging activity, showing 42.00% and 87.22% at 5 μM concentration of DPPH and ·OH scavenging activity, respectively. Furthermore, we studied protective activity of CA from amyloid beta (A${\beta}$_25-35) and lipopolysaccharide (LPS) induced neuronal cell damage and neuronal inflammation using C6 glial cells. The treatment of A${\beta}$_25-35 to C6 glial cell showed declines in cell viability and high generation levels of reactive oxygen species (ROS). However, the treatment of CA increased cell viability. The treatment of 5 ${{\mu}M}$ CA led to the elevation of cell viability from 59.28% to 81.22%. In addition, the production of ROS decreased cellular levels of ROS by the treatment of CA. The treatment of LPS to C6 glial cells increased significant elevation of nitric oxide (NO) production, while CA decreased NO production significantly. The production of NO increased by the treatment of LPS to 131.08%, while CA at the concentration of 1 ${{\mu}M}$ declined the NO production to 104.86%. The present study indicated thatCA attenuated A${\beta}$_25-35-induced neuronal oxidative stress and inflammation by LPS, suggesting as a promising agent for the neurodegenerative diseases.

• 생명과학회지
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• 제21권5호
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• pp.647-655
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• 2011

Amyloid ${\beta}$ ($A{\beta}$)의 신경독성은 알츠하이머병의 주된 원인이 되고 이러한 신경독성은 일련의 신경세포 사멸반응에 의해 일어난다고 알려져 있다. 본 연구에서는 알츠하이머병의 실험모델로 mouse primary neuronal cell에 $A{\beta}_{25-35}$를 처리하여 세포독성을 유도하는 세포실험모델과 C57BL/6J mouse 뇌실에 $A{\beta}_{25-35}$를 주입하여 인지장애를 일으키는 동물실험모델을 이용하여 phosphodiesterase III 억제제인 cilostazol의 신경보호 효과에 대해 조사하였다. $A{\beta}_{25-35}$를 신경세포에 처리하면 세포생존율이 감소되었고, 세포사멸이 일어난 세포의 수도 증가되었다. 이러한 $A{\beta}_{25-35}$에 의한 세포독성이 cilostazol처리에 의해 회복되었으며, peroxisome proliferator-activated receptor(PPAR)-${\gamma}$ 항진제인 rosiglitazone 또한 동일한 회복효과를 나타내었다. Cilostazol과 rosiglitazone에 의한 이러한 회복효과가 PPAR-${\gamma}$ 길항제인 GW9662에 의해 다시 억제되는 결과를 통해 cilostazol의 효과는 PPAR-${\gamma}$가 매개하는 신호전달이 관여함을 알 수 있었다. 직접 PPAR-${\gamma}$ 활성화 정도를 측정한 결과, $A{\beta}_{25-35}$ 처리에 의해 감소된 PPAR-${\gamma}$ 활성화 정도가 cilostazol과 rosiglitazone에 의해 증가함을 관찰할 수 있었고, 이는 GW9662에 의해 다시 억제됨을 확인하였다. 게다가, cilostazol은 세포사멸이 일어난 세포의 수와 세포사멸 조절단백질인 Bax/Bcl-2의 비율도 감소시켰다. Cilostazol (20 mg/kg, 구강투여)을 C57BL/6J mice 뇌실에 $A{\beta}_{25-35}$를 주입하기 2주 동안 전처리하고, $A{\beta}_{25-35}$ 주입 후 4주 동안 처리하면, 기억력과 학습능력을 증진시킨다는 결과를 water maze 실험을 통해 알 수 있었으며, rosiglitazone (10 mg/kg)을 먹인 동물에서도 동일한 결과를 얻을 수 있었다. 본 연구를 통해서 cilostazol이 PPAR-${\gamma}$ 활성화를 통해 $A{\beta}_{25-35}$로 인한 신경세포 손상과 세포사멸을 약화시켜, 신경세포의 생존을 증진시키고, 알츠하이머에서 인지장애를 개선할 것으로 생각된다. 따라서, phosphodiesterase III 억제제인 cilostazol은 알츠하이머 질병 치료에 새로운 전략이 될 수 있을 것이다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2006년도 Spring Conference
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• pp.123-135
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• 2006

Alzheimer's disease (AD) is the most common form of dementia in the aging population and is clinically characterized by a progressive loss of cognitive abilities. Pathologically, it is defined by the appearance of senile plaques - extracellular insoluble, congophilic protein aggregates composed of amyloid $\beta$ (A$\beta$) and neurofibrillary tangles (NFTs) - inyracellular lesions consisting of paired helical filaments from hyperphosphorylated cytoskeletal tau protein as described by Alois Alzheimer a century ago. These hallmarks still serve as the major criteria for a definite diagnosis of the disease. Consequently, one of the key strategy for drug development in this disease area focuses on reducing the concentration of cerebral A$\beta$ plaque by using substances that inhibit A$\beta$ fibril formation. We focused on developing inhibitors by synthesizing several kinds of aromatic molecules. The synthetic compounds were initially screened to evaluate the effective compound by tioflavin T fluorescence assay. The selected effective compounds were tested cytotoxicity and protective effect from A$\beta$-induced neuronal toxicity by cell based MTT assay with HT22 hippocampal neurons. The BBB permeability on effectors was also tested in in vitro co-culture model(HUVEC/C6 cell line). The behavior test wea carried out in mutant APP/PS1 transgenic mouse model of Alzheimer's disease. And inhibition of A$\beta$ fibril formation by the effective compound was monitored with transmitted electron microscopic images.

• 한국식품저장유통학회지
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• 제14권4호
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• pp.425-430
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• 2007

Amyloid ${\beta}-peptide$에 의해 유도되는 세포사멸을 보호하는 물질을 검색하기 위하여 250여 식물 재료 및 식품성분으로부터 스크리닝한 결과 가장 효과가 있는 시금치 추출물을 이용하여 뇌신경세포사멸(neuronal cell death)을 어느 정도 보호할 수 있는지를 알아보았다. 시금치 추출물이 항산화 활성과 acetylcholinesterase 활성에 대한 저해효과는 시금치 추출물 처리농도가 높을수록 유의적으로 높게 나타났다. 과산화수소와 amyloid ${\beta}-peptide$에 의해 유도된 SH-SY5Y 세포주의 세포사멸에 대한 시금치추출액의 억제효과를 살펴본 결과, 과산화수소에 의한 세포사멸에 대하여 시금치 추출물은 억제효과를 나타내었으나, amyloid ${\beta}-peptide$의 경우는 세포사멸억제효과를 나타내지 않았다.