• 생약학회지
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• 제52권3호
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• pp.149-156
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• 2021

Excessive glutamate can cause oxidative stress in neuronal cells and this can be the reason for neurodegenerative disease. In this study, we investigated the protective effect of Spirulina maxima hot ethanol extract on mouse hippocampal HT22 cell of which glutamate receptor has no function. HT22 cells were pre-treated with S. maxima sample at a dose dependent manner (1, 10 and 100 ㎍/ml). After an hour, glutamate was treated. Cell viability, reactive oxygen species (ROS) accumulation, Ca²⁺ influx, decrease of mitochondrial membrane potential level and glutathione related assays were followed by then. S. maxima ethanol extract improved the cell viability by suppressing the ROS and Ca²⁺ formation, retaining the mitochondrial membrane potential level and protecting the activity of the antioxidant enzymes compared with group of vehicle-treated controls. These suggest that S. maxima may decelerate the neurodegeneration by attenuating neuronal damage and oxidative stress.

• Natural Product Sciences
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• 제29권2호
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• pp.67-73
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• 2023

Oxidative stress brings about apoptosis through various mechanisms. In particular, oxidative stress in neuronal cells can causes a variety of brain diseases. This study was conducted to investigate the effect of Bidens tripartita on oxidative stress in neuronal cells. B. tripartita has traditionally been used in Russia as a medicine for diseases such as rhinitis, angina and colitis. Over-production of glutamate induces oxidative stress. When the oxidative stress occurs in the cells, reactive oxygen species (ROS) and Ca²⁺ increase. In addition, the abrupt decline of mitochondrial membrane potential and the decrease of glutathione related enzymes such as glutathione reductase (GR) and glutathione peroxidase (GPx) are also observed. The samples used in the experiment showed cytoprotective effect in the MTT assay. It also lowered the ROS and Ca²⁺ level, and increased degree of mitochondrial membrane potential, GR and GPx. As a result, B. tripartita had a positive effect against oxidative stress. Thus, it is expected to have potential for treatment and prevention of degenerative brain diseases such as Alzheimer's disease.

• The Korean Journal of Physiology and Pharmacology
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• 제26권4호
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• pp.263-275
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• 2022

There is a paucity of detailed data related to the effect of senescence on the mitochondrial antioxidant capacity and redox state of senescent human cells. Activities of TCA cycle enzymes, respiratory chain complexes, hydrogen peroxide (H₂O₂), superoxide anions (SA), lipid peroxides (LPO), protein carbonyl content (PCC), thioredoxin reductase 2 (TrxR2), superoxide dismutase 2 (SOD2), glutathione peroxidase 1 (GPx1), glutathione reductase (GR), reduced glutathione (GSH), and oxidized glutathione (GSSG), along with levels of nicotinamide cofactors and ATP content were measured in young and senescent human foreskin fibroblasts. Primary and senescent cultures were biochemically identified by monitoring the augmented cellular activities of key glycolytic enzymes including phosphofructokinase, lactate dehydrogenase, and glycogen phosphorylase, and accumulation of H₂O₂, SA, LPO, PCC, and GSSG. Citrate synthase, aconitase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase, and complex I-III, II-III, and IV activities were significantly diminished in P25 and P35 cells compared to P5 cells. This was accompanied by significant accumulation of mitochondrial H₂O₂, SA, LPO, and PCC, along with increased transcriptional and enzymatic activities of TrxR2, SOD2, GPx1, and GR. Notably, the GSH/GSSG ratio was significantly reduced whereas NAD⁺/NADH and NADP⁺/NADPH ratios were significantly elevated. Metabolic exhaustion was also evident in senescent cells underscored by the severely diminished ATP/ADP ratio. Profound oxidative stress may contribute, at least in part, to senescence pointing at a potential protective role of antioxidants in aging-associated disease.

• Journal of Genetic Medicine
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• 제1권1호
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• pp.39-43
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• 1997

The mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is inherited maternally, in which the MTTL1*MELAS 3243 mutation has been most commonly found as a heteroplasmy of A to G point mutation in the $tRNA^{Leu(UUR)}$ gene. The MTTL1*MELAS 3271 mutation is known to be the second common mutation, though clinical features of both mutations are not remarkably different. Recently, a variety of minor mutations have been reported in patients with MELAS. In this study, major efforts have been made to investigate the allele frequency of major three mutations including MTTL1*MELAS 3243, 3252, 3271 in 10 Korean families with MELAS probands. The PCR and subsequent direct sequencing of the PCR product in the regions spanning these three mutation sites were employed to identify the mutation in each proband. All family members have been screened for the presence of these three mutations by PCR-RFLP assay using Apa I, Acc I and Bfr I restriction enzymes. The MTTL1*MELAS 3243 mutation was most commonly found (7 out of 10 families tested) followed by the MTTL1*MELAS 3271 which was identified in 1 out of 10 families. In the remaining 2 families none of three mutations were found, indicating the presence of either nuclear mutation or yet unidentified mitochondrial DNA mutation in these families.

• BMB Reports
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• 제54권12호
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• pp.592-600
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• 2021

Parkinson's disease (PD) is one of the most common neurodegenerative diseases in the elderly population and is caused by the loss of dopaminergic neurons. PD has been predominantly attributed to mitochondrial dysfunction. The structural alteration of α-synuclein triggers toxic oligomer formation in the neurons, which greatly contributes to PD. In this article, we discuss the role of several familial PD-related proteins, such as α-synuclein, DJ-1, LRRK2, PINK1, and parkin in mitophagy, which entails a selective degradation of mitochondria via autophagy. Defective changes in mitochondrial dynamics and their biochemical and functional interaction induce the formation of toxic α-synuclein-containing protein aggregates in PD. In addition, these gene products play an essential role in ubiquitin proteasome system (UPS)-mediated proteolysis as well as mitophagy. Interestingly, a few deubiquitinating enzymes (DUBs) additionally modulate these two pathways negatively or positively. Based on these findings, we summarize the close relationship between several DUBs and the precise modulation of mitophagy. For example, the USP8, USP10, and USP15, among many DUBs are reported to specifically regulate the K48- or K63-linked de-ubiquitination reactions of several target proteins associated with the mitophagic process, in turn upregulating the mitophagy and protecting neuronal cells from α-synuclein-derived toxicity. In contrast, USP30 inhibits mitophagy by opposing parkin-mediated ubiquitination of target proteins. Furthermore, the association between these changes and PD pathogenesis will be discussed. Taken together, although the functional roles of several PD-related genes have yet to be fully understood, they are substantially associated with mitochondrial quality control as well as UPS. Therefore, a better understanding of their relationship provides valuable therapeutic clues for appropriate management strategies.

• Animal Bioscience
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• 제35권2호
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• pp.166-176
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• 2022

Objective: Sperm is particularly susceptible to reactive oxygen species (ROS) stress. Glutathione (GSH) is an endogenous antioxidant that regulates sperm redox homeostasis. However, it is not clear whether boar sperm could utilize cysteine for synthesis GSH to protect sperm quality from ROS damage. Therefore, the present study was undertaken to elucidate the mechanism of how cysteine is involved in protecting boar sperm quality during liquid storage. Methods: Sperm motility, membrane integrity, lipid peroxidation, 4-hydroxyIlonenal (4-HNE) modifications, mitochondrial membrane potential, as well as the levels of ROS, GSH, and, ATP were evaluated. Moreover, the enzymes (GCLC: glutamate cysteine ligase; GSS: glutathione synthetase) that are involved in glutathione synthesis from cysteine precursor were detected by western blotting. Results: Compared to the control, addition of 1.25 mM cysteine to the liquid storage significantly increased boar sperm progressive motility, straight-line velocity, curvilinear velocity, beat-cross frequency, membrane integrity, mitochondrial membrane potential, ATP level, acrosome integrity, activities of superoxide dismutase and catalase, and GSH level, while reducing the ROS level, lipid peroxidation and 4-HNE modifications. It was also observed that the GCLC and GSS were expressed in boar sperm. Interestingly, when we used menadione to induce sperm with ROS stress, the menadione associated damages were observed to be reduced by the cysteine supplementation. Moreover, compared to the cysteine treatment, the γ-glutamylcysteine synthetase (γ-GCS) activity, GSH level, mitochondrial membrane potential, ATP level, membrane integrity and progressive motility in boar sperm were decreased by supplementing with an inhibitor of GSH synthesis, buthionine sulfoximine. Conclusion: These data suggest that boar sperm could biosynthesize the GSH from cysteine in vitro. Therefore, during storage, addition of cysteine improves boar sperm quality via enhancing the GSH synthesis to resist ROS stress.

• 생명과학회지
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• 제14권6호
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• pp.913-919
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• 2004

본 연구는 소음성 감각신경성난청 환자의 유전적 관련요인을 파악하고자 관련성이 의심되는 mitochondrial DNA의 돌연변이와 소음성 감각신경성난청과의 관련성을 조사하였다. 말초혈액 백혈구로부터 DNA를 추출한 후, mtDNA 3243, 1555, 7445부위의 $A{\rightarrow}G$ 돌연변이 유무를 관찰하기 위하여 mtDNA 3243, 1555, 7445부위 가 포함된 mtDNA fragment를 중합효소 연쇄반응으로 증폭하고 유전자 제한효소로 소화하여 전기영동하고 ethidium bromide 용액으로 염색하여 UV transilluminator에서 관찰하였다. 그리고, PCR 산물을 이용하여 DNA 염기서열을 분석하여 mtDNA 3243, 1555, 7445부 위에서의 염기서열 분석을 실시하여 mtDNA 3243, 1555, 7445부위 의 $A{\rightarrow}G$ 돌연변이를 관찰하였다 MtDNA A3243G, A1555G, A7445G의 돌연변이를 관찰한 결과 돌연변이 부위가 포함된 fragment가 소음성 감각신경성난청 환자군, 감각신경성난청 환자군, 대조군 모두에서 증폭됨을 관찰하였다. 또한 PCR 산물을 제한효소로 처 리 한 결과에서도 mtDNA에서 3243, 1555, 7445부위의 $A{\rightarrow}G$ 돌연변이가 일어나지 않았음을 알 수 있었다. PCR산물을 이용하여 DNA 염기서열을 분석하여 mtDNA 3243, 1555, 7445부위에서의 염기서열을 확인한 결과 이미 밝혀진 사람의 mtDNA 3243, 1555, 7445부 위의 염기서열과 동일한 염기서열임이 확인되었으므로 mtDNA 3243, 1555, 7445부위의 $A{\rightarrow}G$ 돌연변이가 일어나지 않았음을 확인하였다. 소음성 감각신경성난청과 mtDNA 3243, 1555, 7445부위의 $A{\rightarrow}G$ 돌연변이와는 관련이 없는 것으로 관찰되었다.

• 생명과학회지
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• 제29권11호
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• pp.1179-1191
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• 2019

암세포는 epithelial mesenchymal transition (EMT)를 통해 tumor invasion과 metastasis가 일어나며, 또한 정상세포와 다른 oncogenic metabolic phenotypes 획득 즉, glycolytic switch 등이 암 발생과 진행에 깊이 연관되어 있음이 잘 알려져 있다. High-mobility group box 1 (HMGB1)은 chromatin-associated nuclear protein으로 알려져 있으나, dying cells 또는 immune cells로부터 방출되기도 한다. 방출된 HMGB1은 damage-associated molecular pattern (DAMP)로서 작용하여 EMT 및 invasion, metastasis를 유도함으로서 tumor progression에 기여한다고 알려졌다. 본 연구에서 HMGB1에 의해 EMT와 glycolytic switch 유도되며, 이 과정은 Snail 의존적임을 확인하였다. 또한 HMGB1/Snail cascade는 COX subunits인 COXVIIa와 COXVIIc의 발현 억제를 통해 mitochondrial repression과 cytochrome c oxidase (COX) inhibition을 유도하였다. HMGB1은 Snail를 통해 glycolytic switch의 주요 효소인 hexokinase 2 (HK2), phosphofructokinase-2/fructose-2,6-bisphosphatase 2 (PFKFB2), phosphoglycerate mutase 1 (PGAM1)의 발현을 증가시켰다. 이들 효소는 glycolytic switch에 중요하게 관여하는 것으로 알려져 있다. 이들 해당과정의 효소들을 knockdown한 결과 HMGB1에 의한 EMT를 억제함으로써 glycolysis와 HMGB1-induced EMT가 밀접하게 연관되어 있을 제시하였다. 이상의 연구 결과들은 HMGB1/Snail cascade가 EMT 및 glycolytic switch, mitochondrial repression에 중요하게 작용할 것임을 시사한다.

• BMB Reports
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• 제46권2호
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• pp.86-91
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• 2013

Glucose effects on the vegetative growth of Dictyostelium discoideum Ax2 were studied by examining oxidative stress and tetrahydropteridine synthesis in cells cultured with different concentrations (0.5X, 7.7 g $L^{-1}$; 1X, 15.4 g $L^{-1}$; 2X, 30.8 g $L^{-1}$) of glucose. The growth rate was optimal in 1X cells (cells grown in 1X glucose) but was impaired drastically in 2X cells, below the level of 0.5X cells. There were glucose-dependent increases in reactive oxygen species (ROS) levels and mitochondrial dysfunction in parallel with the mRNA copy numbers of the enzymes catalyzing tetrahydropteridine synthesis and regeneration. On the other hand, both the specific activities of the enzymes and tetrahydropteridine levels in 2X cells were lower than those in 1X cells, but were higher than those in 0.5X cells. Given the antioxidant function of tetrahydropteridines and both the beneficial and harmful effects of ROS, the results suggest glucose-induced oxidative stress in Dictyostelium, a process that might originate from aerobic glycolysis, as well as a protective role of tetrahydropteridines against this stress.

• 대한유전성대사질환학회지
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• 제13권1호
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• pp.43-47
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• 2013

Introduction: ALT/AST enzymes are present inside the cells. AST is found in cardiac and skeletal muscle and red blood cells but the ALT is checked mainly in the liver. In general, the rise of these two indicators shows liver damage. The usual measurements of these enzymes are used in liver function tests, but the levels of AST and ALT do not always reflect liver function. Method and Cases: 17 cases of liver dysfunction transiently were evaluated clinically, biochemically, and imaging study of sonogram in pediatric in-patients for 3 years. Result: Most common causes of transient liver dysfunction were infection, especially viral gastroenteritis, and bacterial infection interfering oral food intake. More often occurred in the children who have infant hyperbilirubinemia, positive history of mitochondrial dysfunction or hypoglycemia. Fasting study in one case of hypoglycemia patient showed reversible liver dysfunction during fasting over 20 hours fasting. Discussion: A significant increase in AST and ALT with normal bilirubin can be observed in clinically healthy people during blunt trauma, viral infection, severe pain, metabolic syndrome, fasting or accidental health screening.