• Title/Summary/Keyword: Amyloid aggregation

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Antioxidant and Anti-amyloid Activities of Fermented Kalopanax pictus (엄나무 발효물의 항산화 및 항아밀로이드 활성)

  • Kang, Jung Hoon
    • Journal of the Korean Applied Science and Technology
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    • v.35 no.2
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    • pp.389-398
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    • 2018
  • This study was to investigate the antioxidant and anti-amyloid activities of the extract (KP-HE) from Kalopanax pictus (KP) fermented with Hericium erinaceum (HE) mycelium. Antioxidant activity was evaluated based on 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical(ABTS) scavenging assays. In all assays, the extracts from KP, HE and KP-HE had the potential for antioxidant activities. However, antioxidant activity of KP-HE significantly scavenged DPPH radical as compared to the KP and HE. The result suggested that the antioxidant component was increased in the process of KP fermented with HE. KP-HE was shown to significantly inhibite peroxyl radical-mediated DNA strand breakage whereas KP and HE did not inhibit DNA strand breakage. The aggregation of the amyloid-${\beta}$ ($A{\beta}$) peptide is involved in the pathological process of Alzheimer's disease(AD). In this study, the effects of KP, HE and KP-HE on the aggregation of $A{\beta}_{1-42}$ were investigated. KP and HE had little effect on $A{\beta}$ aggregation and KP-HE effectively inhibited $A{\beta}$ aggregation. KP-HE effectively inhibited $A{\beta}$ induced cell death and significantly increased of the 20.3% cell survival at $300{\mu}g/mL$ concentration. KP-HE also decreased intracellular reactive oxygen specie levels in $A{\beta}$-treated cells. The results suggested that KP-HE had antioxidant and anti-amyloid activities. Therefore, KP-HE could potentially be used as a valuable functional food ingredient to prevent neurodegenerative disorders such as AD.

Inhibition of ${\beta}-amyloid_{1-40}$ Peptide Aggregation and Neurotoxicity by Citrate

  • Park, Yong-Hoon;Kim, Young-Jin;Son, Il-Hong;Yang, Hyun-Duk
    • The Korean Journal of Physiology and Pharmacology
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    • v.13 no.4
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    • pp.273-279
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    • 2009
  • The accumulation of ${\beta}$-amyloid (A${\beta}$) aggregates is a characteristic of Alzheimer's disease (AD). Furthermore, these aggregates have neurotoxic effects on cells, and thus, molecules that inhibit A${\beta}$ aggregate formation could be valuable therapeutics for AD. It is well known that aggregation of A${\beta}$ depends on its hydrophobicity, and thus, in order to increase the hydrophilicity of A${\beta}$, we considered using citrate, an anionic surfactant with three carboxylic acid groups. We hypothesized that citrate could reduce hydrophobicity and increase hydrophilicity of A${\beta}_{1-40}$ molecules via hydrophilic/electrostatic interactions. We found that citrate significantly inhibited A${\beta}_{1-40}$ aggregation and significantly protected SH-SY5Y cell line against A${\beta}_{1-40}$ aggregates-induced neurotoxicity. In details, we examined the effects of citrate on A${\beta}_{1-40}$ aggregation and on A${\beta}_{1-40}$ aggregates-induced cytotoxicity, cell viability, and apoptosis. Th-T assays showed that citrate significantly inhibited A${\beta}_{1-40}$ aggregation in a concentration-dependent manner (Th-T intensity: from 91.3% in 0.01 mM citrate to 82.1% in 1.0 mM citrate vs. 100.0% in A${\beta}_{1-40}$ alone). In cytotoxicity and viability assays, citrate reduced the toxicity of A${\beta}_{1-40}$ in a concentration-dependent manner, in which the cytotoxicity decreased from 107.5 to 102.3% as compared with A${\beta}_{1-40}$ aggregates alone treated cells (127.3%) and the cell viability increased from 84.6 to 93.8% as compared with the A${\beta}_{1-40}$ aggregates alone treated cells (65.3%). Furthermore, Hoechst 33342 staining showed that citrate (1.0 mM) suppressed A${\beta}_{1-40}$ aggregates-induced apoptosis in the cells. This study suggests that citrate can inhibit A${\beta}_{1-40}$ aggregation and protect neurons from the apoptotic effects of A${\beta}_{1-40}$ aggregates. Accordingly, our findings suggest that citrate administration should be viewed as a novel neuroprotective strategy for AD.

Oxidative Modification of Neurofilament-L by Copper-catalyzed Reaction

  • Kim, Nam-Hoon;Kang, Jung-Hoon
    • BMB Reports
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    • v.36 no.5
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    • pp.488-492
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    • 2003
  • Neurofilament-L (NF-L) is a major element of neuronal cytoskeletons and known to be important for neuronal survival in vivo. Since oxidative stress might play a critical role in the pathogenesis of neurodegenerative diseases, we investigated the role of copper and peroxide in the modification of NF-L. When disassembled NF-L was incubated with copper ion and hydrogen peroxide, then the aggregation of protein was proportional to copper and hydrogen peroxide concentrations. Dityrosine crosslink formation was obtained in copper-mediated NF-L aggregates. The copper-mediated modification of NF-L was significantly inhibited by thiol antioxidants, N-acetylcysteine, glutathione, and thiourea. A thioflavin-T binding assay was performed to determine whether the copper/$H_2O_2$ system-induced in vitro aggregation of NF-L displays amyloid-like characteristics. The aggregate of NF-L displayed thioflavin T reactivity, which was reminiscent of amyloid. This study suggests that copper-mediated NF-L modification might be closely related to oxidative reactions which may play a critical role in neurodegenerative diseases.

The Effects of SWS(Sahyang·Woohwang·Samchilkeun) on Hyperlipidemia and Brain Damage (사향(麝香)·우황(牛黃)·삼칠근(三七根) 복합방(複合方)이 고지혈증(高脂血症) 및 뇌손상(腦損傷)에 미치는 영향(影響))

  • Park, Jung-yang;Kim, Byeong-tak
    • Journal of Haehwa Medicine
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    • v.8 no.1
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    • pp.425-449
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    • 1999
  • For the evaluation of the effect on SWS, experiments were made on hyperlipidemia induced by hypercholesterol diet, inhibitory reaction to human platelet aggregation, Pulmonary thrombosis induced by collagen and epinephrine, global cerebral ischemia induced by KCN, brain ischemia induced by MCA occlusion, cytotoxicity of PC12 cells induced by amyloid ${\beta}$ protein(25-35), and NO production in RAW cells stimulated by lipopolysaccharide. The results were obtained as follows : 1. In the experiment on hyperlipidemia, the level of serum total cholesterol, phospholipid, and LDL-cholesterol were significantly decreased while the level of triglyceride, VLDL-cholesterol, and HDL-cholesterol had no significant change. 2. In the experiment on inhibitory reaction to platelet aggregation, SWS inhibited platelet aggregation induced by ADP(36.05%), by collagen(20.4%), and by thrombin(0.6%). 3. In the experiment on pulmonary thrombosis induced by collagen and epinephrine, the protective effect was found(37%). 4. In the experiment on global cerebral ischemia, coma duration induced by KCN changed insignificantly. 5. In the experiment on MCA occlusion, the change of neurologic grades on hind limb was significant only after the operation. Besides brain ischemic area and edema ratio were significantly decreased. 6. In the experiment on cytotoxicity of PC 12 cells induced by amyloid ${\beta}$ protein, the significant protective effect was found as concentration increases. 7. In the experiment on NO production in RAW cells stimulated by lipopolysaccharide, NO was significantly decreased. According to the results, it is expected that SWS might be effective on hyperlipidemia and brain damage.

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Screening of 56 Herbal formulas covered by the National Health Insurance Service on Dementia-related Factors (국민 건강보험 급여 한약 처방 56종의 치매 주요 생리지표 및 신경세포 변화에 대한 효능 비교 연구)

  • Lim, Hye-Sun;Kim, Yu Jin;Kim, Yoon ju;Kim, Bu-Yeo;Jeong, Soo-Jin
    • The Journal of Korean Medicine
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    • v.39 no.3
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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.

Study on the effect of Buthus martensi Karsch extract on thrombosis and brian damage (전갈(全蝎) 추출물(抽出物)이 혈전증(血栓症), 전뇌허혈(全腦虛血) 및 뇌세포독성(腦細胞毒性)에 미치는 영향(影響))

  • Baek, Myung-Hyun;Hwang, Yong-Geun;Jeong, Ji-Cheon;Kang, Jeong-Jun;Kim, Sung-Hoon
    • The Journal of Dong Guk Oriental Medicine
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    • v.8 no.1
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    • pp.171-190
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    • 1999
  • This following is effect of Buthus martensi Karsch(BMK) extract on dextran-thrombus model, KCN-induced coma, cytotoxicity of brain etc. BMK extract significantly increased number of platelet and fibrogen and significantly shortened the prothrombin time as compared with control group treated with dextran. BMK extract didn't affect the changes of hematocrit as compared with control group treated with dextran. BMK extract induced a significant inhibition of human platelet aggregation induced by thrombin and ADP but did not affect human platelet aggregation induced by collagen. BMK extract showed a protective effect on pulmonary thrombosis induced by collagen and epinephrine. BMK extract prolonged the duration of KCN-induced coma and showed a protective effect on cytotoxicity of PC12 cells induced by amyloid ${\beta}$ protein(25-35) in a dose dependent manner. These results suggested that BMK extract might be usefully applied for prevention and treatment of thrombosis and brain damage.

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Acrolein, the toxic endogenous aldehyde, induces neurofilament-L aggregation

  • Jeong, Moon-Sik;Kang, Jung-Hoon
    • BMB Reports
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    • v.41 no.9
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    • pp.635-639
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    • 2008
  • Acrolein is a highly reactive by product of lipid peroxidation and individuals with neurodegenerative disorders have been shown to contain elevated concentrations of this molecule in the brain. In the present study, we examined the pattern of neurofilament-L (NF-L) modification elicited by acrolein. When NF-L was incubated with acrolein, protein aggregation occurred in a acrolein concentration-dependent manner. Exposure of NF-L to acrolein also led to the generation of protein carbonyl compounds. Through the addition of free radical scavengers we observed a significant decrease in acrolein-mediated NF-L aggregation. These results indicate that free radicals may be involved in the modification of NF-L by acrolein. In addition, dityrosine crosslink formation was observed in acrolein-mediated NF-L aggregates and these aggregates displayed thioflavin T reactivity, reminiscent of amyloid. This study suggests that acrolein-mediated NF-L aggregation might be closely related to oxidative reactions, thus these reactions may play a critical role in neuro-degenerative diseases.

Protection by Histidine Dipeptides against Acrolein-induced Neurofilament-L Aggregation

  • Kang, Jung-Hoon
    • Bulletin of the Korean Chemical Society
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    • v.29 no.9
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    • pp.1732-1736
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    • 2008
  • The endogenous dipeptides, carnosine and related compounds, are the naturally occurring dipeptides with multiple neuroprotective properties. We have examined the protective effects of carnosine, homocarnosine and anserine on the aggregation of neurofilament-L (NF-L) induced by neurotoxin, acrolein. When NF-L was incubated with acrolein in the presence of carnosine, homocarnosine or anserine, protein aggregation was inhibited in a concentration-dependent manner. These compounds inhibited the formation of protein carbonyl compounds and dityrosine in acrolein-mediated NF-L aggregates. The aggregates of NF-L displayed thioflavin T reactivity, reminiscent of amyloid. This thioflavin T reactivity was inhibited by carnosine and related compounds. This effect was associated with decreased formation of oxidatively modified proteins. Our results suggested that carnosine and related compounds might have protective effects to brain proteins under pathophysiological conditions leading to degenerative damage such as neurodegenerative disorders.

NMR-based structural characterization of transthyretin in its aggregation-prone state

  • Kim, Bokyung;Kim, Jin Hae
    • Journal of the Korean Magnetic Resonance Society
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    • v.24 no.3
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    • pp.91-95
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    • 2020
  • Transthyretin (TTR) is an abundant protein in blood plasma and cerebrospinal fluid (CSF), working as a homo-tetrameric complex to transport thyroxine (T4) and a holo-retinol binding protein. TTR is well-known for its amyloidogenic property; several types of systemic amyloidosis diseases are caused by aggregation of either wild-type TTR or its variants, for which more than 100 mutations were reported to increase the amyloidogenicity of TTR. The rate-limiting step of TTR aggregation is the dissociation of a monomeric subunit from a tetrameric complex. A wide range of biochemical and biophysical techniques have been employed to elucidate the TTR aggregation processes, among which nuclear magnetic resonance (NMR) spectroscopy contributed much to characterize the structural and functional features of TTR during its aggregation processes. The present review focuses on discussing the recent advances of our understanding to the amyloidosis mechanism of TTR and to the structural features of its monomeric aggregation-prone state in solution. We expect that the present review provides novel insights to appreciate the molecular basis of TTR amyloidosis and to develop novel therapeutic strategies to treat diverse TTR-related diseases.