• Journal of Ginseng Research
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• v.45 no.6
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• pp.642-653
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• 2021

Background: Effective strategies are dramatically needed to prevent and improve the recovery from myocardial ischemia and reperfusion (I/R) injury. Direct interactions between the mitochondria and endoplasmic reticulum (ER) during heart diseases have been recently investigated. This study was designed to explore the cardioprotective effects of gypenoside XVII (GP-17) against I/R injury. The roles of ER stress, mitochondrial injury, and their crosstalk within I/R injury and in GP-17einduced cardioprotection are also explored. Methods: Cardiac contractility function was recorded in Langendorff-perfused rat hearts. The effects of GP-17 on mitochondrial function including mitochondrial permeability transition pore opening, reactive oxygen species production, and respiratory function were determined using fluorescence detection kits on mitochondria isolated from the rat hearts. H9c2 cardiomyocytes were used to explore the effects of GP-17 on hypoxia/reoxygenation. Results: We found that GP-17 inhibits myocardial apoptosis, reduces cardiac dysfunction, and improves contractile recovery in rat hearts. Our results also demonstrate that apoptosis induced by I/R is predominantly mediated by ER stress and associated with mitochondrial injury. Moreover, the cardioprotective effects of GP-17 are controlled by the PI3K/AKT and P38 signaling pathways. Conclusion: GP-17 inhibits I/R-induced mitochondrial injury by delaying the onset of ER stress through the PI3K/AKT and P38 signaling pathways.

• Journal of Life Science
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• v.27 no.3
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• pp.361-369
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• 2017

Mitochondrial homeostasis is tightly regulated by two major processes: mitochondrial biogenesis and mitochondrial degradation by autophagy (mitophagy). Research in mitochondrial biogenesis in skeletal muscle in response to endurance exercise training has been well established, while the mechanisms regulating mitophagy and the relationship between mitochondrial biogenesis and degradation following endurance exercise training are not yet well defined. Studies have demonstrated that endurance exercise training increases the expression levels of mitochondrial biogenesis-, dynamics-, mitophagy-related genes in skeletal muscle. However, the increased levels of mitochondrial biogenesis marker proteins such as Cox IV and citrate synthase, by endurance exercise training were abolished when autophagy/mitophagy was inhibited in skeletal muscle. This suggests that both autophagy/mitophagy plays an important role in mitochondrial biogenesis/homeostasis and the coordination between the opposing processes may be important for skeletal muscle adaptation to endurance exercise training to improve metabolic function and endurance exercise performance. It is considered that endurance exercise training regulates each of these processes, mitochondrial biogenesis, fusion and fission events and autophagy/mitophagy, ensuring a relatively constant mitochondrial population. Exercise training may also have contributed to mitochondrial quality control which replaces old and/or unhealthy mitochondria with new and/or healthy ones in skeletal muscle. In this review paper, the molecular mechanisms regulating mitochondrial biogenesis and mitophagy and the coordination between the opposing processes is involved in the cellular adaptation to endurance exercise training in skeletal muscle will be discussed.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.97-97
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• 1997

It was reported that ATP depletion occurs and accelerates cell damage during ischemia and reperfusion. To determine the mechanism of cell damage, the change of energy metabolism in liver was studied during ischemia/reperfusion. The groups were divided into four categories : sham-operated group, ischemia/reperfusion group, and two types of ATP-MgCl$_2$ treatment groups(one was treated during ischemia and the another during reperfusion). Rats were administered intravenously saline or ATP-MgCl$_2$. Rats were anesthetized and blood vessels in the left and median lobes of the liver were occluded. After 60min of ischemia, the clamp at those vessels were removed. After ischemia, one and five hours after reflow, energy metabolites(ATP, ADP, AMP, inosine, adenosine, hypoxanthine, xanthine) in liver were measured with HPLC. To observe mitochondrial function, aterial keton body ratio in blood and mitochondrial glutamate dehydrogenase activity in liver were measured. And lipid peroxidation was measured to evalutate the involvement of free radicals. In this study, ATP and ADP were catabolized to their metabolites(AMP, inosine, adenosine, hypoxanthine, xanthine) during ischemia and they resynthesized ATP and ADP during reperfusion. But total purine base were not restored to level of normal rat. The main source of resynthesizing ATP and ADP was AMP. In both ATP-MgCl$_2$ treated groups, mitochondrial function was protected and lipid peroxidation was significantly reduced. Our findings suggest that ischemia/reperfusion impairs hepatic energy metabolism.

• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.230-233
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• 2000

The present work was designed to determine whether change in fluidity of the mitochondrial membrane affects mitochondrial {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase characteristics in NIDDM-prone BHE/Cdb rat. Isolated mitochondria fom BHE/Cdb rat fed a 6% coconut oil or corn oil were functionally tested by an analysis of its respiration and the coupling of this process to ATP synthesis in presence of oligomycin, a specific inhibitor of oxidative phosphorylation (OXPHOS), that binds to the {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase. Mitochondria from rats fed coconut oil were more responsive to the inhibitory action of oligomycin with respect to state 3 respiration, respiratory control (RC) ratio and ADP:P (P/O) ratio than were mitochondria from rats fed corn oil. In state 3 respiration, mitochondria from rats fed coconut oil consumed less oxygen than did mitochondria from rats fed corn oil. RC ratio was lower in the mitochondria from rats fed coconut oil than was mitochondria from rats fed corn oil. In P/O ratio, the mitochondria from rats fed coconut oil had a lower P/O ratio than did mitochondria from rats fed corn oil. The data showed that the chang influidity of the mitochondrial membrane by dietary fat affected mitochondrial {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase characteristics. The present study on diet differences in {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase characteristics provides considerable insight into the role diets play in the control of mitochondrial function, expecially OXPHOS in NIDDM with mitochondrial defects.

• Journal of Pharmacopuncture
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• v.18 no.3
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• pp.68-74
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• 2015

Objectives: The present study was undertaken to determine the modulatory effect of taurine on the liver mitochondrial enzyme system with reference to mitochondrial lipid peroxidation (LPO), antioxidants, major tricarboxylic acid cycle enzymes, and electron transport chain enzymes during 7,12-dimethyl benz[a]anthracene (DMBA) induced breast cancer in Sprague-Dawley rats. Methods: Animals in which breast cancer had been induced by using DMBA (25 mg/kg body weight) showed an increase in mitochondrial LPO together with decreases in enzymic antioxidants (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST)), non-enzymic antioxidants (reduced glutathione (GSH), vitamin C, and vitamin E), in citric acid cycle enzymes (isocitrate dehydrogenase (ICDH), alpha ketoglutarate dehydrogenase (alpha KDH), succinate dehydrogenase (SDH) and malate dehydrogenase (MDH)), and in electron transport chain (ETC) complexes. Results: Taurine (100 mg/kg body weight) treatment decreased liver mitochondrial LPO and augmented the activities/levels of enzymic, and non-enzymic antioxidants, tricarboxylic acid cycle enzymes and ETC complexes. Conclusion: The results of our present study demonstrated the chemotherapeutic efficacy of taurine treatment for DMBA-induced breast carcinomas.

• The Korean Journal of Mycology
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• v.17 no.3
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• pp.161-168
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• 1989

Mitochondria in L. edodes were separated and purified by stepped sucrose density gradient centrifugation. In our previous work, we have found that the activation wavelengths of the mitochondrial ATPase and ATP synthase were 680 nm and 470 nm within the range of 400-700 nm, respectively. The activities of the above enzymes with wavelengths of 300-400 nm region were investigated. The mitochondrial ATPase and ATP synthase were stimulated at 380 nm and 330 nm, respectively, for 30 min illumination compared with dark control group. They, however, were inhibited at 330 nm and 350 nm, respectively. The presence of FAD resulted in inhibition of the activity of the ATPase and stimulation of the activity of the ATP synthase by the activation and inhibition wavelengths. However, the activities of these enzymes were not changed by NADH for the above wavelengths. In the spectral properties, the oxidation of $FADH_2$ into FAD occurs in the presence of the enzymes for illumination of the activation and inhibition wavelengths. Therefore, we can predict that the mitochondrial ATPase and ATP synthase may function as oxidant in the redox reaction by the light illumination and that the light-induced pigment of the mitochondrial ATP synthase should be an oxidized form of a flavoprotein.

• YAKHAK HOEJI
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• v.43 no.6
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• pp.851-860
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• 1999

The effects of antimycin A(AA), dodium azide ($NaN_3$) and 2,4-dinitrophenol (DNP), which inhibit mitochondrial ATP production, on cellular functions of cultured astrocytes were studied. High concentrations of AA $(50{\;}\mu\textrm{g}/ml),{\;}NaN_3$ (100mM) and DNP (20mM) significantly decreased 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction, which was known to be related to mitochondrial function and then cel viability. AA ($50{\;}\mu\textrm{g}/ml$) increased lactate dehydrogenase (LDH) release and decreased [$^3H$] glutamate uptake, suggesting severe damage of cellular function by the concentrations of the compounds. Meanwhile, low concentrations of AA $(\leq{;\}10{\;}\mu\textrm{g}/ml),{\;}NaN_3{;\}(\leq{\;}50mM)$ and DNP ($\leq{\;}5mM$) significantly increased MTT reduction, the effect of which was specific to astrocytes. AA (5 and $10{\;}\mu\textrm{g}/ml$) did not affect LDH release and [$^3H$] glutamate uptake, indicating that these compounds increased MTT reduction at the low concentrations without cellular membrane damage. However, the low concentrations of AA produced significant decrease of MTT reduction in a glucose-free medium. Low concentrations of AA (1 and $5{\;}\mu\textrm{g}/ml$) did not change ATP production of astrocytes in the medium containing 10 mM glucose, but completely inhibited in a glucose-free medium, suggesting marked increase of cytosolic ATP production by the blockade of mitochondrial ATP production with low concentrations of AA. These results suggest that astrocytes have ability to enhance neuronal function or survival under conditions of incomplete ischemia or early by enhancement of glycolysis, and that cellular reduction of MTT occurs not only mitochondrially but also extramitchondrially.

• Molecules and Cells
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• v.39 no.7
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• pp.543-549
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• 2016

MicroRNAs (miRNAs) have been reported to be involved in many neurodegenerative diseases. The present study focused on the role of hsa-miR-144-3p in one of the neuro-degenerative diseases, Parkinson's disease (PD). Our study showed a remarkable down-regulation of miR-144-3p expression in 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-treated SH-SY5Y cells. MiR-144-3p was then overexpressed and silenced in human SH-SY5Y cells by miRNA-mimics and miRNA-inhibitor transfections, respectively. Furthermore, ${\beta}$-amyloid precursor protein (APP) was identified as a target gene of miR-144-3p via a luciferase reporter assay. We found that miR-144-3p overexpression significantly inhibited the protein expression of APP. Since mitochondrial dysfunction has been shown to be one of the major pathological events in PD, we also focused on the role of miR-144-3p and APP in regulating mitochondrial functions. Our study demonstrated that up-regulation of miR-144-3p increased expression of the key genes involved in maintaining mitochondrial function, including peroxisome proliferator-activated receptor ${\gamma}$ coactivator-$1{\alpha}$(PGC-$1{\alpha}$), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM). Moreover, there was also a significant increase in cellular ATP, cell viability and the relative copy number of mtDNA in the presence of miR-144-3p overexpression. In contrast, miR-144-3p silencing showed opposite effects. We also found that APP overexpression significantly decreased ATP level, cell viability, the relative copy number of mtDNA and the expression of these three genes, which reversed the effects of miR-144-3p overexpression. Taken together, these results show that miR-144-3p plays an important role in maintaining mitochondrial function, and its target gene APP is also involved in this process.

• Integrative Medicine Research
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• v.2 no.4
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• pp.131-138
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• 2013

The skeletal muscle in our body is a major site for bioenergetics and metabolism during exercise. Carbohydrates and fats are the primary nutrients that provide the necessary energy required to maintain cellular activities during exercise. The metabolic responses to exercise in glucose and lipid regulation depend on the intensity and duration of exercise. Because of the increasing prevalence of obesity, recent studies have focused on the cellular and molecular mechanisms of obesity-induced insulin resistance in skeletal muscle. Accumulation of intramyocellular lipid may lead to insulin resistance in skeletal muscle. In addition, lipid intermediates (e.g., fatty acyl-coenzyme A, diacylglycerol, and ceramide) impair insulin signaling in skeletal muscle. Recently, emerging evidence linking obesity-induced insulin resistance to excessive lipid oxidation, mitochondrial overload, and mitochondrial oxidative stress have been provided with mitochondrial function. This review will provide a brief comprehensive summary on exercise and skeletal muscle metabolism, and discuss the potential mechanisms of obesity-induced insulin resistance in skeletal muscle.

• Parasites, Hosts and Diseases
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• v.53 no.4
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• pp.421-430
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• 2015

The parasite Plasmodium falciparum causes severe malaria and is the most dangerous to humans. However, it exhibits resistance to their drugs. Farnesyltransferase has been identified in pathogenic protozoa of the genera Plasmodium and the target of farnesyltransferase includes Ras family. Therefore, the inhibition of farnesyltransferase has been suggested as a new strategy for the treatment of malaria. However, the exact functional mechanism of this agent is still unknown. In addition, the effect of farnesyltransferase inhibitor (FTIs) on mitochondrial level of malaria parasites is not fully understood. In this study, therefore, the effect of a FTI R115777 on the function of mitochondria of P. falciparum was investigated experimentally. As a result, FTI R115777 was found to suppress the infection rate of malaria parasites under in vitro condition. It also reduces the copy number of mtDNA-encoded cytochrome c oxidase III. In addition, the mitochondrial membrane potential (${\Delta}{\Psi}m$) and the green fluorescence intensity of MitoTracker were decreased by FTI R115777. Chloroquine and atovaquone were measured by the mtDNA copy number as mitochondrial non-specific or specific inhibitor, respectively. Chloroquine did not affect the copy number of mtDNA-encoded cytochrome c oxidase III, while atovaquone induced to change the mtDNA copy number. These results suggest that FTI R115777 has strong influence on the mitochondrial function of P. falciparum. It may have therapeutic potential for malaria by targeting the mitochondria of parasites.