• Molecules and Cells
• /
• v.40 no.7
• /
• pp.503-514
• /
• 2017

Nicotinamide (NAM) plays essential roles in physiology through facilitating $NAD^+$ redox homeostasis. Importantly, at high doses, it protects cells under oxidative stresses, and has shown therapeutic effectiveness in a variety of disease conditions. In our previous studies, NAM lowered reactive oxygen species (ROS) levels and extended cellular life span in primary human cells. In the treated cells, levels of $NAD^+/NADH$ and SIRT1 activity increased, while mitochondrial content decreased through autophagy activation. The remaining mitochondria were marked with low superoxide levels and high membrane potentials (${\Delta}_{{\Psi}m}$); we posited that the treatment of NAM induced an activation of mitophagy that is selective for depolarized mitochondria, which produce high levels of ROS. However, evidence for the selective mitophagy that is mediated by SIRT1 has never been provided. This study sought to explain the mechanisms by which NAM lowers ROS levels and increases ${\Delta}_{{\Psi}m}$. Our results showed that NAM and SIRT1 activation exert quite different effects on mitochondrial physiology. Furthermore, the changes in ROS and ${\Delta}_{{\Psi}m}$ were not found to be mediated through autophagy or SIRT activation. Rather, NAM suppressed superoxide generation via a direct reduction of electron transport, and increased ${\Delta}_{{\Psi}m}$ via suppression of mitochondrial permeability transition pore formation. Our results dissected the effects of cellular $NAD^+$ redox modulation, and emphasized the importance of the $NAD^+/NADH$ ratio in the mitochondria as well as the cytosol in maintaining mitochondrial quality.

• Journal of Nutrition and Health
• /
• v.42 no.5
• /
• pp.442-452
• /
• 2009

Smoking has been known to exacerbate the initiation and propagation of oxidative stresses. Efforts have been made to reduce the smoking-induced oxidative stresses using commercial dietary supplements. Propolis is the resinous substance collected by bees from the leaf buds and bark of trees, especially poplar and conifer trees. In this trial, we examined whether a daily supplementation of 800 mg propolis can protect endogenous lymphocytic DNA damage and modulate antioxidative enzyme activities and the level of antioxidant vitamin in smokers using a placebo-controlled, doubleblinded cross-over trial. After two weeks of running-in period, 29 smokers (mean age 34.38 ${\pm}$ 1.73) received 6 tablets/day of either propolis or placebo pills for 4 weeks. After 2 weeks of washout period the subjects switched they pills for cross-over study. The degree of DNA damage (assessed by tail DNA, tail length and tail moment) was not significantly changed with propolis intake or placebo intake. Similarly, total antioxidant status (TAS) remained at the same level regardless of the treatment. Erythrocyte catalase, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), plasma vitamin C and tocopherol level did not differ before and after propolis treatment, and did not differ between treatments. Putting all these results together, we would suggest that it is still too early to claim that propolis possess antioxidative activities.

• Journal of Ginseng Research
• /
• v.24 no.3
• /
• pp.113-117
• /
• 2000

To analyze the correlation between the rusty root and the antiokidative activity in ginseng (Panax ginseng C.A.Meyer) roots, the levels of antioxidative activity in various tissues of healthy and rusty roots. The superoxide dismutase activity in rusty roots (126.9 units/mg protein) was approximately 3.5 times higher than that in healthy roots. The catalase activity in rusty roots was approximately 1.6 times higher than that in healthy roots, whereas the peroxidase activity showed a slight low level in msty roots. The 1.1 diphenyl-2-picryl-hydrazyl(DPPH) free radical scavenging activity in rusty roots was approximately 2.0 times higher than that in healthy roots. The total ascorbate content in healthy roots was 166~240 $\mu\textrm{g}$/g fr. wt. depending on the tissues. Interestingly, the oxidized dehydroascorbate (DHA) content occupied more than 80% in total ascorbate content. The total ascorbate content in rusty roots was a similar level with healthy roots, but the reduced ascorbate content was 3.5~7.5 times higher than that of the healthy roots. The total glutathione content of the epidermis, cortex and stele tissues in 겨sty roots was 7.3, 4.8, 1.2 times higher than the healthy tissues, respectively. The ratio of reduced glutathione (GSH) and oxidized glutathione (GSSG) showed a similar fluctuation of total glutathione content in 겨sty roots. These results indicate that the high antioxidative activity in rusty roots may involve in overcoming the oxidative stress derived from environmental stresses.

• Journal of Life Science
• /
• v.25 no.10
• /
• pp.1169-1175
• /
• 2015

Although many studies have described the physiological effects of bee products, such as honey, propolis, pollen, and royal jelly, the health benefits of honeycomb remain incompletely characterized. We performed a comparative study of the antioxidant properties of honey and honeycomb extracts using two different solvents (water and 95% ethanol). The results showed that the total phenolic and flavonoid content of the honeycomb extract was higher than that of the honey extract. They also demonstrated that water was more effective than ethanol in extracting total phenols. The in vitro antioxidant properties of the water honeycomb extract were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO^•) radical scavenging assays and ferrous ion chelating and reducing power assays. The antioxidant activity of the honeycomb extract exhibited was higher than that of the honey extract. The 50% effective concentrations (EC₅₀) of the honeycomb extract were 7.3±0.26 mg/ml for scavenging DPPH radicals, 6.1±0.22 mg/ml for scavenging NO^• radicals, 6.9±0.44 mg/ml for chelating ferrous ions, and 8.2±0.11 mg/ml for reducing power. A correlation analysis revealed that the total phenolics and flavonoids of the honeycomb extract were the major contributors to the radical scavenging activity, ferrous ion chelating, and reducing power. The honeycomb extract was effective in protecting biological systems against various oxidative stresses in vitro. This is the first report on the antioxidant properties of honeycomb.

• Biomedical Science Letters
• /
• v.9 no.4
• /
• pp.241-248
• /
• 2003

Sodium salicylate, a plant stress hormone that plays an important role(s) in defenses against pathogenic microbial and herbivore attack, has been shown to induce a variety of cell responses such as anti-inflammation, cell cycle arrest and apoptosis in animal cells. p38MAPK plays a critical role(s) in the cell regulation by sodium salicylate. However, the signal pathway for sodium salicylate-induced p38MAPK activation is yet unclear. In this study, we show that although sodium salicylate enhances reactive oxygen species (ROS) production, N-acetyl-L-cysteine, a general ROS scavenger, did not prevent sodium salicylate-induced p38MAPK, indicating ROS-independent activation of p38MAPK by sodium salicylate. Sodium salicylate-activated p38MAPK appeared to be very rapidly down-regulated 2 min after removal of sodium salicylate. Interestingly, sodium salicylate-pretreated cells remained fully responsive to re-induction of p38MAPK activity by a second sodium salicylate stimulation or by other stresses, $H_2O$$_2$ and methyl jasmonate (MeJA), thereby indicating that sodium salicylate does not exhibit both homologous and heterologous desensitization. In contrast, pre-exposure to MeJA, $H_2O$$_2$, heat shock, or hyperosmotic stress reduced the responsiveness to subsequent homologous stimulation. Sodium salicylate was able to activate p38MAPK in cells desensitized by other heterologous p38MAPK activators. These results indicate that there is a sensing mechanism highly specific to sodium salicylate for activation of p38MAPK, distinct trom pathways used by other stressors such as MeJA, $H_2O$$_2$ heat shock, and hyperosmotic stress.

• Journal of Environmental Science International
• /
• v.24 no.7
• /
• pp.917-925
• /
• 2015

Styela clava tunic is generated in large amounts as a waste from S. clava processing plants and leads to environmental problems. It destroys the beach scenery and causes a bad smell and pollution by trashing on the seashore. Therefore, purpose of this study was to investigate antioxidant and antihypertensive activities of different solvent extracts from S. clava tunic for recycling of fishery waste. Antioxidant and antihypertensive activities of all extracts were concentration-dependent. Of extracts, hot water extract showed the highest DPPH radical scavenging activity with the lowest effective concentration ($EC_{50}$) value (0.733 mg/ml). Chloroform extract exhibited the highest metal chelation activity with the lowest $EC_{50}$ value (2.696 mg/ml). Autoclaved water extract showed the highest NO radical scavenging activity with the lowest $EC_{50}$ value (0.491 mg/ml) and n-hexane extract showed the highest reducing power ($A_{700}=1.897$ at 100 mg/ml). And n-butanol extract showed the highest SOD-like activity with the lowest $EC_{50}$ value (19.116 mg/ml) and ACE inhibition activity with the lowest inhibitory concentration($IC_{50}$) value (0.149 mg/ml). These results indicate that extracts obtained from S. clava tunic may potential candidate to reduce diseases caused by various oxidative stresses and hypertension.

• Biomolecules & Therapeutics
• /
• v.20 no.1
• /
• pp.27-35
• /
• 2012

Oroxylin A is a flavone isolated from a medicinal herb reported to be effective in reducing the inflammatory and oxidative stresses. It also modulates the production of brain derived neurotrophic factor (BDNF) in cortical neurons by the transactivation of cAMP response element-binding protein (CREB). As a neurotrophin, BDNF plays roles in neuronal development, differentiation, synaptogenesis, and neural protection from the harmful stimuli. Adenosine $A2_A$ receptor colocalized with BDNF in brain and the functional interaction between $A2_A$ receptor stimulation and BDNF action has been suggested. In this study, we investigated the possibility that oroxylin A modulates BDNF production in cortical neuron through the regulation of $A2_A$ receptor system. As expected, CGS21680 ($A2_A$ receptor agonist) induced BDNF expression and release, however, an antagonist, ZM241385, prevented oroxylin A-induced increase in BDNF production. Oroxylin A activated the PI3K-Akt-GSK-$3{\beta}$ signaling pathway, which is inhibited by ZM241385 and the blockade of the signaling pathway abolished the increase in BDNF production. The physiological roles of oroxylin A-induced BDNF production were demonstrated by the increased neurite extension as well as synapse formation from neurons. Overall, oroxylin A might regulate BDNF production in cortical neuron through $A2_A$ receptor stimulation, which promotes cellular survival, synapse formation and neurite extension.

• 한국균학회소식:학술대회논문집
• /
• 2014.10a
• /
• pp.15-15
• /
• 2014

Fusarium graminearum (teleomorph Gibberella zeae) is an important plant pathogen that causes head blight of major cereal crops such as wheat, barley, and rice, as well as causing ear and stalk rot on maize worldwide. Plant diseases caused by this fungus lead to severe yield losses and accumulation of harmful mycotoxins in infected cereals [1]. Fungi utilize spore production as a mean to rapidly avoid unfavorable environmental conditions and to amplify their population. Spores are produced sexually and asexually and their production is precisely controlled. Upstream developmental activators consist of fluffy genes have been known to orchestrate early induction of condiogenesis in a model filamentous fungus Aspergillus nidulans. To understand the molecular mechanisms underlying conidiogenesis in F. graminearum, we characterized functions of the F. graminearum fluffy gene homologs [2]. We found that FlbD is conserved regulatory function for conidiogenesis in both A. nidulans and F. graminearum among five fluffy gene homologs. flbD deletion abolished conidia and perithecia production, suggesting that FlbD have global roles in hyphal differentiation processes in F. graminearum. We further identified and functionally characterized the ortholog of AbaA, which is involved in differentiation from vegetative hyphae to conidia and known to be absent in F. graminearum [3]. Deletion of abaA did not affect vegetative growth, sexual development, or virulence, but conidium production was completely abolished and thin hyphae grew from abnormally shaped phialides in abaA deletion mutants. Overexpression of abaA resulted in pleiotropic defects such as impaired sexual and asexual development, retarded conidium germination, and reduced trichothecene production. AbaA localized to the nuclei of phialides and terminal cells of mature conidia. Successful interspecies complementation using A. nidulans AbaA and the conserved AbaA-WetA pathway demonstrated that the molecular mechanisms responsible for AbaA activity are conserved in F. graminearum as they are in A. nidulans. F. graminearum ortholog of Aspergillus nidulans wetA has been shown to be involved in conidiogenesis and conidium maturation [4]. Deletion of F. graminearum wetA did not alter mycelial growth, sexual development, or virulence, but the wetA deletion mutants produced longer conidia with fewer septa, and the conidia were sensitive to acute stresses, such as oxidative stress and heat stress. Furthermore, the survival rate of aged conidia from the F. graminearum wetA deletion mutants was reduced. The wetA deletion resulted in vigorous generation of single-celled conidia through autophagy-dependent microcycle conidiation, indicating that WetA functions to maintain conidia dormancy by suppressing microcycle conidiation in F. graminearum. In A. nidulans, FlbB physically interacts with FlbD and FlbE, and the resulting FlbB/FlbE and FlbB/FlbD complexes induce the expression of flbD and brlA, respectively. BrlA is an activator of the AbaA-WetA pathway. AbaA and WetA are required for phialide formation and conidia maturation, respectively [5]. In F. graminearum, the AbaA-WetA pathway is similar to that of A. nidulans, except a brlA ortholog does not exist. Amongst the fluffy genes, only fgflbD has a conserved role for regulation of the AbaA-WetA pathway.

• Korean Journal of Microbiology
• /
• v.52 no.2
• /
• pp.236-241
• /
• 2016

The Schizosaccharomyces pombe $sdu1^+$ gene, belonging to the PPPDE superfamily of deubiquitinating enzyme (DUB) genes, was previously shown to encode a protein with ubiquitin C-terminal hydrolase (UCH) activity and to participate in the response against oxidative and nitrosative stresses. This work focused on the reactive oxygen species (ROS)-dependent regulation of the S. pombe $sdu1^+$ gene. UCH activities, encoded by the $sdu1^+$ gene, were attenuated in the S. pombe cells exposed to $H_2O_2$, superoxide radical-generating menadione (MD), and nitric oxide (NO)-generating sodium nitroprusside (SNP). Reduced glutathione (GSH) and its precursor N-acetylcysteine (NAC) were able to significantly enhance the UCH activities in the absence or presence of $H_2O_2$. However, the influences of both GSH and NAC on the ROS levels in the absence or presence of $H_2O_2$ were opposite to their effects on the UCH activities under the same conditions. The UCH activities in the Sdu1-overexpressing S. pombe cells were also diminished under exposure to $H_2O_2$, MD and SNP, but still remained to be higher than those in the vector control cells. In brief, it is proposed that the S. pombe $sdu1^+$ gene is regulated by ROS in a negative manner, the meaning of which largely remains elusive.

• Animal Bioscience
• /
• v.34 no.10
• /
• pp.1590-1599
• /
• 2021

Objective: This study investigates the expression patterns of toll-like receptors (TLRs) and intracellular mediators in horse muscle cells after exercise, and the relationship between TLRS expression in stressed horse muscle cells and immune cell migration toward them. Methods: The expression patterns of the TLRs (TLR2, TLR4, and TLR8) and downstream signaling pathway-related genes (myeloid differentiation primary response 88 [MYD88]; activating transcription factor 3 [ATF3]) are examined in horse tissues, and horse peripheral blood mononuclear cells (PBMCs), polymorphonuclear cells (PMNs) and muscles in response to exercise, using the quantitative reverse transcription-polymerase chain reaction (qPCR). Expressions of chemokine receptor genes, i.e., C-X-C motif chemokine receptor 2 (CXCR2) and C-C motif chemokine receptor 5 (CCR5), are studied in PBMCs and PMNs. A horse muscle cell line is developed by transfecting SV-T antigen into fetal muscle cells, followed by examination of muscle-specific genes. Horse muscle cells are treated with stressors, i.e., cortisol, hydrogen peroxide (H₂O₂), and heat, to mimic stress conditions in vitro, and the expression of TLR4 and TLR8 are examined in stressed muscle cells, in addition to migration activity of PBMCs toward stressed muscle cells. Results: The qPCR revealed that TLR4 message was expressed in cerebrum, cerebellum, thymus, lung, liver, kidney, and muscle, whereas TLR8 expressed in thymus, lung, and kidney, while TLR2 expressed in thymus, lung, and kidney. Expressions of TLRs, i.e., TLR4 and TLR8, and mediators, i.e., MYD88 and ATF3, were upregulated in muscle, PBMCs and PMNs in response to exercise. Expressions of CXCR2 and CCR5 were also upregulated in PBMCs and PMNs after exercise. In the muscle cell line, TLR4 and TLR8 expressions were upregulated when cells were treated with stressors such as cortisol, H₂O₂, and heat. Migration of PBMCs toward stressed muscle cells was increased by exercise and oxidative stresses, and combinations of these. Treatment with methylsulfonylmethane (MSM), an antioxidant on stressed muscle cells, reduced migration of PBMCs toward stressed muscle cells. Conclusion: In this study, we have successfully cultured horse skeletal muscle cells, isolated horse PBMCs, and established an in vitro system for studying stress-related gene expressions and function. Expression of TLR4, TLR8, CXCR2, and CCR5 in horse muscle cells was higher in response to stressors such as cortisol, H₂O₂, and heat, or combinations of these. In addition, migration of PBMCs toward muscle cells was increased when muscle cells were under stress, but inhibition of reactive oxygen species by MSM modulated migratory activity of PBMCs to stressed muscle cells. Further study is necessary to investigate the biological function(s) of the TLR gene family in horse muscle cells.