• Plant Biotechnology Reports
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• v.2 no.2
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• pp.113-122
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• 2008

Nitric oxide (NO) affects the growth and development of plants and also affects plant responses to various stresses. Because NO induces root differentiation, we examined whether or not it is involved in increased ROS generation. Treatments with sodium nitroprusside (SNP), an NO donor, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), a specific NO scavenger, and $N{\omega}-nitro-{\text\tiny{L}}-arginine$ methyl ester hydrochloride (${\text\tiny{L}}-NAME$), an NO synthase (NOS) inhibitor, revealed that NO is involved in the adventitious root growth of mountain ginseng. Supply of an NO donor, SNP, activates NADPH oxidase activity, resulting in increased generation of $O_2{^{{\cdot}-}}$, which subsequently induces growth of adventitious roots. Moreover, treatment with diphenyliodonium chloride (DPI), an NADPH oxidase inhibitor, individually or with SNP, inhibited root growth, NADPH oxidase activity, and $O_2{^{{\cdot}-}}$ anion generation. Supply of the NO donor, SNP, did not induce any notable isoforms of enzymes; it did, however, increase the activity of pre-existing bands of NADPH oxidase, superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase. Enhanced activity of antioxidant enzymes induced by SNP supply seems to be responsible for a low level of $H_2O_2$ in the adventitious roots of mountain ginseng. It was therefore concluded that NO-induced generation of $O_2{^{{\cdot}-}}$ by NADPH oxidase seems to have a role in adventitious root growth of mountain ginseng. The possible mechanism of NO involvement in $O_2{^{{\cdot}-}}$ generation through NADPH oxidase and subsequent root growth is discussed.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.2
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• pp.99-106
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• 2009

Although anti-atherogenic effects of cilostazol have been suggested, its effects on the expression of SR in macrophages are unclear. This study investigated the role of cilostazol on CD36 expression of murine macrophages enhanced by HNE, a byproduct of lipid peroxidation. The stimulation of macrophages with HNE led to an increased expression of CD36, which was significantly attenuated by NAC, an antioxidant. Moreover, the increased production of ROS by HNE was completely abolished by NADPH oxidase inhibitors, DPI and apocynin, as well as by the 5-LO inhibitor, MK886, but not by inhibitors for other oxidases. This suggested that NADPH-oxidase and 5-LO were major sources of ROS induced by HNE. In addition, HNE-enhanced expression of CD36 was reduced by these inhibitors, which indicated a role for NADPH oxidase and 5-LO on CD36 expression. In our present study, cilostazol was a significant inhibitor of ROS production, as well as CD36 expression induced by HNE. An increase in NADPH oxidase activity by HNE was significantly attenuated by cilostazol, however cilostazol had no effect on HNE-enhanced 5-LO activity. Together, these results suggest that cilostazol attenuates HNE-enhanced CD36 expression on murine macrophages thorough inhibition of NADPH oxidase-derived ROS generation.

• IMMUNE NETWORK
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• v.14 no.5
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• pp.241-248
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• 2014

It is debatable whether AMP-activated protein kinase (AMPK) activation is involved in anti-apoptotic or pro-apoptotic signaling. AICAR treatment increases AMPK-${\alpha}1$ phosphorylation, decreases intracellular reactive oxygen species (ROS) levels, and significantly increases Annexin V-positive cells, DNA laddering, and caspase activity in human myeloid cell. AMPK activation is therefore implicated in apoptosis. However, AMPK-${\alpha}1$-knockdown THP-1 cells are more sensitive to apoptosis than control THP-1 cells are, suggesting that the apoptosis is AMPK-independent. Low doses of AICAR induce cell proliferation, whereas high doses of AICAR suppress cell proliferation. Moreover, these effects are significantly correlated with the downregulation of intracellular ROS, strongly suggesting that AICAR-induced apoptosis is critically associated with the inhibition of NADPH oxidase by AICAR. Collectively, our results demonstrate that in AICAR-induced apoptosis, intracellular ROS levels are far more relevant than AMPK activation.

• Molecules and Cells
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• v.27 no.5
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• pp.557-562
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• 2009

We examined the effects of the NADPH oxidase p22phox C242T polymorphism on endurance exercise performance and oxidative DNA damage in response to acute and chronic exercises. One hundred three subjects were recruited, among which 26 healthy subjects (CC: 12, TC: 12, and TT: 2) were studied during rest, exercise at 85% $VO_2max$, and recovery before and after 8 weeks of treadmill running. Lymphocyte DNA damage increased significantly in response to exercise (p < 0.05). There were no significant differences in plasma MDA, SOD concentrations and lymphocyte DNA damage between CC genotype and T allele group, but significant endurance training differences were observed. Endurance training increased exercise time to exhaustion in both the CC genotype and T allele groups (p < 0.05) but no significant difference was found between groups. The results of the current study with young, healthy, Korean men are interpreted to mean that 1) the majority had the CC genotype of the NADPH oxidase p22phox C242T polymorphism (82.5%: CC, 15.5%: TC, 1.9%: TT), 2) acute exercise increased lymphocyte DNA damage, 3) endurance training significantly increased exercise time to exhaustion, and alleviated lymphocyte DNA damage, and 4) The NADPH oxidase p22phox C242T polymorphism, however, did not alter lymphocyte DNA damage or exercise performance at rest, immediately after exercise, or during recovery.

• Biomolecules & Therapeutics
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• v.26 no.2
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• pp.191-200
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• 2018

Chalcone, (2E)-1,3-Diphenylprop-2-en-1-one, and its synthetic derivatives are known to possess anti-oxidative and anti-inflammatory properties. In the present study, we prepared a novel synthetic chalcone compound, (E)-1-(4-hydroxyphenyl)-3-(2-(trifluoromethoxy)phenyl)prop-2-en-1-one name (YJI-7), and investigated its inhibitory effects on endotoxin-stimulated production of reactive oxygen species (ROS) and expression of inflammatory mediators in macrophages. We demonstrated that treatment of RAW 264.7 macrophages with YJI-7 significantly suppressed lipopolysaccharide (LPS)-stimulated ROS production. We also found that YJI-7 substantially decreased NADPH oxidase activity stimulated by LPS, indicating that YJI-7 regulates ROS production via modulation of NADPH oxidase in macrophages. Furthermore, YJI-7 strongly inhibited the expression of a number of inflammatory mediators in a gene-selective manner, suggesting that YJI-7 possesses potent anti-inflammatory properties, as well as anti-oxidative activity. In continuing experiments to investigate the mechanisms that could underlie such biological effects, we revealed that YJI-7 suppressed phosphorylation of p38MAPK and JNK stimulated by LPS, whereas no significant effect on ERK was observed. Furthermore, LPS-stimulated production of ROS, activation of NADPH oxidase and expression of inflammatory mediators were markedly suppressed by treatment with selective inhibitor of p38MAPK (SB203580) and JNK (SP600125). Taken together, these results demonstrated that YJI-7, a novel synthetic chalcone derivative, suppressed LPS-stimulated ROS production via modulation of NADPH oxidase and diminished expression of inflammatory mediators, at least in part, via down-regulation of p38MAPK and JNK signaling in macrophages.

• Natural Product Sciences
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• v.24 no.1
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• pp.59-65
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• 2018

An isoform of NADPH oxidase (NOX), NOX2 is a superoxide-generating enzyme involved in diverse pathophysiological events. Although its potential as a therapeutic target has been validated, there is no clinically available inhibitor. Herein, NOX2-inhibitory activity was screened with the constituents isolated from Schisandra chinensis, which has been reported to have antioxidant and reactive oxygen species (ROS)-scavenging effects. Among the partitions prepared from crude methanolic extract, a chloroform-soluble partition showed the highest NOX2-inhibitory activity in PLB-985 cell-based NOX2 assay. A total of twenty nine compounds (1 - 29) were identified from the chloroform fraction, including two first isolated compounds; dimethyl-malate (25) and 2-(2-hydroxyacetyl) furan (27) from this plants. Of these constituents, two compounds (gomisin T, and pregomisin) exhibited an NOX2-inhibitory effect with the $IC_{50}$ of $9.4{\pm}3.6$, and $62.9{\pm}11.3{\mu}M$, respectively. They are confirmed not to be nonspecific superoxide scavengers in a counter assay using a xanthine-xanthine oxidase system. These findings suggest the potential application of gomisin T (6) and other constituents of S. chinensis to inhibit NOX2.

• YAKHAK HOEJI
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• v.31 no.6
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• pp.361-369
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• 1987

The four azo dyes such as Amaranth (FD & C Red No. 2), Tartrazine (FD & C Yellow No. 4), sunset Yellow (FD & C Yellow No. 5) and Allura red (FD & C Red No. 40) are currently employed as a food additives in Korea. In this study, the effects of these azo dyes on the hepatic microsomal mixed function oxidase systems in Rats. (i.e., Cyt. P-450, Cyt. b$_5$, NADPH cyt. c-reductase and azo reductase) were investigated. Furthermore, to determine the relationship among the electron transport systems, each level of azo reductase, Cyt. P-450 and NADPH cyt. c-reductase was measured upon the administration of phenobarbital (known as an inducer of Cyt. P-450), 3-methylcholanthrene (Known as an inducer of Cyt. P-448), CoCl$_2$ (inhibitor on Cyt. P-450) or $CCl_4$ (inhibitor on Cyt. P-450). The results of these studies are as follows; (1) The levels of Cyt. P-450 and Cyt. b$_5$ were decreased upon the administration of these azo dyes. (2) When the level of Cyt. P-450 was decreased, the azo reductase activity was also decreased. (3) These azo dyes did not show any significant effect on the level of NADPH cyt. c-reductase. (4) The administration of 3-methylcholanthrene resulted in the elevation of azo reductase activity. The 3-methylcholanthrene may be responsible for the induction of CO-insensitive electron transport system.

• Environmental Mutagens and Carcinogens
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• v.22 no.4
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• pp.229-235
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• 2002

Thimerosal, a widely used preservative, has been well known to induce intracellular calcium mobilization in various cell types. However, the mechanism of its calcium mobilization is not clearly understood yet. For studying the mechanism of thimerosal-mediated calcium release, we have used HL60 cells in calcium-free Lockes solution that has no extracellular calcium. Thimerosal significantly reduced the lag period of initial calcium release whereas it enhanced the rate and magnitude of the calcium release in a dose-dependent manner. At the same time, we found that thimerosal generated superoxide anion by activating NADPH oxidase in dose- and time-dependent manner. Interestingly, the kinetics and the dosedependency of superoxide anion generation were very similar to those of intracellular calcium mobilization. In inhibitors study, the thimerosal-induced superoxide anion generation was significantly suppressed by DMSO as well as superoxide dismutase but not by genistein or EGTA. Surprisingly, the pretreatment with N-Acetyl-$_{L}$-Cysteine blocked almost completely the thimerosal-induced calcium increase, indicating that ROS playa key role in the calcium mobilization. The present results suggest that thimerosal-induced calcium mobilization is possibly mediated by the activation of NADPH oxidase and subsequent ROS generation.n.

• Journal of Genetic Medicine
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• v.10 no.1
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• pp.1-6
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• 2013

Chronic granulomatous disease (CGD) is a rare inherited disorder of a defective NADPH oxidase enzyme, resulting in very low or no production of superoxide and subsequent reactive oxygen species. Consequently, patients with CGD are highly susceptible to severe bacterial and fungal infections. CGD is a genetically heterogeneous disease caused by defects in any one of the genes encoding the NADPH oxidase components. CGD generally affects about 3-4 per 1,000,000 individuals; thus, it is surprising that the prevalence of CGD on Jeju Island is 34.3 per 1,000,000 individuals. At present, 20 patients with CGD from 14 unrelated families on Jeju Island have been identified; nine males and 11 females. All patients with CGD tested on Jeju Island had an identical and homozygous mutation (c.7C>T in CYBA, p.Q3X in $p22^{phox}$). Therefore, all patients were autosomal recessive form of CGD. This strongly suggests that the unique and identical mutation in CYBA may be inherited from a common proband. Using mutation-specific primers to detect the mutated allele in CYBA, the frequency of subjects carrying a mutated allele was 1.3% of enrolled subjects from Seogwipo City. Further studies are necessary to elucidate how frequently this mutant allele occurs in the population on Jeju Island. Additionally, it is important to construct a national registry system to understand the pathophysiology of CGD and develop a strategy for long-term therapy.

• Journal of Periodontal and Implant Science
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• v.36 no.4
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• pp.863-878
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• 2006

Porphyromonas gingivalis는 치주질환을 야기하는 독성세균으로서, 구강상피세포에 p. gingivalis가 감염되었을 때, 세포형태에 변화를 초래함으로 인해 방어기작이 작동하게 된다. 치주질환과 관련되어 생성된 활성 산소종의 소거에 관여하는 항산화성분은 p. gingivalis 이 감염된 구강상피세포에서 그 분포와 발현수준이 달라지리라 예상된다. 따라서 이번 연구에서는 구강상피세포(KB 세포)에 p. gingivalis가 감염되었을 때 야기되는 활성산소종과 이를 소거하는 역할을 하는 항산화단백들의 역할들을 규명하고자 하였다. 활성산소종 형성을 조절하는 NADPH oxidase 중 NOX4와 Rac1 전사체는 구강상피세포에서 p. gingivalis세균에 의해 증가하였으며 $gp91^{phox}$, Rac2, $p47^{phox}$와 $p67^{phox}$는 세균에 의한 변화가 관찰되지 않았다. 반면에 $p40^{phox}$ 전사체는 감소하는 경향을 보였다. NOX1 전사체는 p. gingivalis 처리 30분 후 감소하였다가 60분 후에는 다시 증가하는 양상을 보였다. 같은 시간에 NOX 활성화 단백인 NOXA1은 감소하고, NOX 구성단백질인 NOXO1은 증가하는 경향을 보였다. p. gingivalis가 감염된 구강상피세포를 방어하는 항산화단백 발현수준을 평가한 결과, SOD1, 2, 3 모두 p. gingivalis 처리시간에 따라 증가하는 양상을 보였다. GPx 발현 양상도 SOD와 유사하게 나타났다. $H_2O_2$를 소거하는 Prx는 감염된 KB 세포에서 Prx4와 Prx5가 4-6배 증가하는 것을 알 수 있었다. 반면 endocytosis 과정 중 $H_2O_2$ 생산은 변화되지 않았다. 이번 연구의 결과, p. gingivalis의 감염은 KB 세포의 NOX4와 Rac1의 NADPH oxidase 발현을 증가시켰으며, NOX1은 NOXA1과 NOXO1의 조절에 의해 영향을 받음을 알 수 있었다. 또한 항산화기작으로는 SOD, GPx, Prx가 증가하였는데, 이것은 Prx4와 Prx5가 중요한 역할을 할 것을 시사하였다.