• Biomolecules & Therapeutics
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• v.26 no.1
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• pp.39-44
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• 2018

In 1923, Dr. Warburg had observed that tumors acidified the Ringer solution when 13 mM glucose was added, which was identified as being due to lactate. When glucose is the only source of nutrient, it can serve for both biosynthesis and energy production. However, a series of studies revealed that the cancer cell consumes glucose for biosynthesis through fermentation, not for energy supply, under physiological conditions. Recently, a new observation was made that there is a metabolic symbiosis in which glycolytic and oxidative tumor cells mutually regulate their energy metabolism. Hypoxic cancer cells use glucose for glycolytic metabolism and release lactate which is used by oxygenated cancer cells. This study challenged the Warburg effect, because Warburg claimed that fermentation by irreversible damaging of mitochondria is a fundamental cause of cancer. However, recent studies revealed that mitochondria in cancer cell show active function of oxidative phosphorylation although TCA cycle is stalled. It was also shown that blocking cytosolic NADH production by aldehyde dehydrogenase inhibition, combined with oxidative phosphorylation inhibition, resulted in up to 80% decrease of ATP production, which resulted in a significant regression of tumor growth in the NSCLC model. This suggests a new theory that NADH production in the cytosol plays a key role of ATP production through the mitochondrial electron transport chain in cancer cells, while NADH production is mostly occupied inside mitochondria in normal cells.

• BMB Reports
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• v.49 no.2
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• pp.116-121
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• 2016

Although proteomic analyses have revealed the presence of mitochondrial oxidative phosphorylation (OXPHOS) proteins in the plasma membrane, there have been no in-depth evaluations of the presence or function of OXPHOS I-V in the plasma membrane. Here, we demonstrate the in situ localization of OXPHOS I-V complexes to the sarcolemma of skeletal muscle by immunofluorescence and immunohistochemistry. A portion of the OXPHOS I-V complex proteins was not co-stained with MitoTracker but co-localized with caveolin-3 in the sarcolemma of mouse gastrocnemius. Mitochondrial matrix-facing OXPHOS complex subunits were ectopically expressed in the sarcolemma of the non-permeabilized muscle fibers and C2C12 myotubes. The sarcolemmal localization of cytochrome c was also observed from mouse gastrocnemius muscles and C2C12 myotubes, as determined by confocal and total internal resonance fluorescence (TIRF) microscopy. Based on these data, we conclude that a portion of OXPHOS complexes is localized in the sarcolemma of skeletal muscle and may have non-canonical functions.

• Journal of Community Nutrition
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• v.7 no.3
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• pp.163-168
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• 2005

The present investigation was undertaken in vivo to determine whether the functional alterations of hepatic mitochondria induced by ethanol might be prevented by taurine. We examined the effects of supplementation of taurine on hepatic mitochondrial oxidative phosphorylation in the chronic ethanol-administered rats. Isolated hepatic mitochondria from three groups of rats were functionally tested by an analysis of $\beta-hydroxbutyrate-supported$ respiration and the coupling of this process to ATP synthesis in the presence of ADP. The three groups were control group(CO), ethanol(60g/L) administered group (AL), and ethanol (60g/L) + taurine (5g/L) supplemented group (AT). Ethanol and/or taurine were given in drinking water for 10 weeks. The mitochondria from AL group had lower state 4 respiratory rate, respiratory control (RC) ratio and ADP : O(P/O) ratio than those from CO and AT group. It showed that the ethanol administered rats were less coupled and thus less efficient with respect to mitochondrial ATP synthesis than both control rats and ethanol + taurine supplemented rats. It suggests that taurine supplementation might improve the impaired oxidative phosphorylation efficiency in mitochondrial dysfunction that is recognized as a cause of liver diseases in chronic ethanol consumption.

• Animal cells and systems
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• v.14 no.2
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• pp.91-98
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• 2010

Male rats were given a single injection of iron, and temporal changes in iron content and iron-induced effects were examined in heart cellular fractions. Over a period of 72 h, the contents of total and labile iron, reactive oxygen species, and NO in tissue homogenate, nuclear debris, and postmitochondrial fractions were mostly constant, but in mitochondria they continuously increased. An abrupt decrease in membrane potential and NAD(P)H at 12 h was also found in mitochondria. The respiratory control ratio was reduced slowly with a slight recovery at 72 h, suggesting uncoupling by iron.While the ATP content of tissue homogenate decreased steadily until 72 h, it showed a prominent increase in mitochondria at 12 h. Total iron and calcium concentration also progressively increased in mitochondria over 72 h. Enzyme activity of the oxidative phosphorylation system was significantly altered by iron injection: activities of complexes I, III, and IV were reduced considerably, but complex II activity and the ATPase activity of complex V were enhanced. A reversal of activity in complexes I and II at 12 h suggested reverse electron transfer due to iron overload. These results support the argument that mitochondrial activities including oxidative phosphorylation are modulated by excessive iron.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.35-41
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• 2013

Metabolic analysis of CR6 interacting factor 1 (Crif1) deficient mouse embryonic fibroblasts with impaired oxidative phosphorylation has been carried out using LC-MS/MS and GC-MS methods. Metabolic profiles of the Crif1 deficient cells were comprehensively obtained for the first time. Loss of oxidative phosphorylation functions in mitochondria resulted in cancer-like metabolic reprogramming with consumption of majority of glucose carbon from up-regulated glycolysis to produce lactate, suppressed utilization of glucose carbon in the TCA cycle, increased amounts of amino acids. The changes in metabolic profile of the Crif1 deficient cells are most probably a consequence of metabolic reprogramming to meet the needs of energy balance and anabolic precursors in compensation for the loss of major oxidative phosphorylation functions.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.841-848
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• 2008

Archyranthes radix has had extensive therapeutic application, and there has been increasing interest in its biological effects. However, the biochemical effects of Archyranthes radix on chondrocyte oxidative stress have never been systematically investigated. Therefore, we investigated the effects of Acyranthes radix on role of MAPK signal transduction pathway on oxidative stress induced by hydrogen peroxide in rat articular chondrocytes. The statistically significant inhibitory action of Archyranthes radix on cell proliferation was observed at above $5{\mu}g/m{\ell}$. Next, we examined the time-dependent effect of $5{\mu}g/m{\ell}$ Archyranthes radix on cell proliferaion. Archyranthes radix significantly inhibited cell proliferation from 12 hr after treatment (P<0.05). $H_2O_2$, resulted in a time- and dose-dependent cell proliferation, which was largely attributed to oxidative damage. Acyranthes radix and $H_2O_2$ treatment caused marked sustained activation of phosphorylation of ERK1/2. Moreover, the synergistic phosphorylation of p44/42 MAPK by $H_2O_2$ and Archyranthes radix was selectively inhibited by PD 98059, a p44/42 MAPK inhibitor. In conclusion, these results are consistent with the hypothesis that under conditions of oxidative stress, the $H_2O_2$-induced inhibition of cell proliferation in the rat chondrocyte is mediated through a modulation of the Archyranthes radix signaling pathway, promoting further phosphorylation of p44/42 MAPK, indicating a potentially important role in cartilage repair and in the treatment of osteoarthritic cartilage.

• Korean Journal of Radiology
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• v.23 no.5
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• pp.566-567
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• 2022

• Korean Journal of Microbiology
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• v.2 no.1
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• pp.12-16
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• 1964

Lee, Yung Nok and Chin, Pyung (Dept. of Biology, Korea University, Seoul, Korea) : Action of ascorbic acid indoleacetic acid on the oxidation of succinate and coupled phosphorylation in Chlorella mitochondria. Kor. Jour. Microbiol., Vol.2, No.1, p12-16 (1964) Mitochondria were isolated from Chlorella ellipsoidea and the action of ascorbic acid and indoleacetic acid on the succinate oxidation and coupled phosphorylation in mitochondria suspension were examined. Oxidation of succinate used as substrate, and phosphorylation coupled to oxidation were strikingly enhanced by the addition of ascorbic acid, while in case of indoleacetic acid it were a little. In a view of phosphorylative efficiency, P/O ratio resulting from the addition of ascorbic acid was decreased and it may be considered as the result of a partial oxidation of ascorbate in mitochondria.

• Herbal Formula Science
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• v.31 no.1
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• pp.29-39
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• 2023

Objective : Gardeniae Fructus (GF) is the ripe fruit of Gardenia jasminoides Ellisa with a bitter taste and cold properties. Ingredient compounds including geniposide are known to have anti-inflammatory, antioxidant, and neuroprotective effects. The purpose of this study was to investigate the neuroprotective effect of GF on tBHP-induced PC12 cells. Methods : Cell viability was measured by the MTT assay, and apoptosis was determined by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The expression level of each protein was monitored by Western blot analysis, and reactive oxygen species (ROS) were analyzed using DCFH-DA. Results : In PC12 cells, tBHP induced cell death through apoptosis with caspase activation and PARP inactivation. Cells treated with tBHP showed an increase in intracellular ROS and depletion of GSH. Pretreatment with GF prevented tBHP-induced apoptosis, reduced ROS, and increased GSH. GF also maintained increased Nrf2 expression in the presence of tBHP. Phosphorylation of JNK and p38 MAPK was increased by tBHP, whereas phosphorylation of ERK was decreased. GF restored changes in ERK and p38 phosphorylation, but not JNK phosphorylation. Conclusion : These results indicate that GF has neuroprotective effects through anti-apoptotic and antioxidant effects mediated by regulation of Nrf2 expression and phosphorylation of ERK and p38. It also demonstrates the potential use of GF as a source of antioxidant and neuroprotective substances.

• Toxicological Research
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• v.30 no.4
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• pp.235-242
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• 2014

Cancer cells are known to drastically alter cellular energy metabolism. The Warburg effect has been known for over 80 years as pertaining cancer-specific aerobic glycolysis. As underlying molecular mechanisms are elucidated so that cancer cells alter the cellular energy metabolism for their advantage, the significance of the modulation of metabolic profiles is gaining attention. Now, metabolic reprogramming is becoming an emerging hallmark of cancer. Therapeutic agents that target cancer energy metabolism are under intensive investigation, but these investigations are mostly focused on the cytosolic glycolytic processes. Although mitochondrial oxidative phosphorylation is an integral part of cellular energy metabolism, until recently, it has been regarded as an auxiliary to cytosolic glycolytic processes in cancer energy metabolism. In this review, we will discuss the importance of mitochondrial respiration in the metabolic reprogramming of cancer, in addition to discussing the justification for using mitochondrial DNA somatic mutation as metabolic determinants for cancer sensitivity in glucose limitation.