• Nutritional Sciences
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• 제9권1호
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• pp.9-13
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• 2006

The differential effects of various fatty acids such as n-3 and n-6 types or degrees of unsaturation on the CYP2E1 induction and the production of lipid peroxidation (LPO) were investigated. The CYP2E1-transduced human hepatoma HepG2 cells (E47) were cultured in RPMI 1640 media containing different concentrations of various fatty acids up to 48 h incubation compared to 04 cells and CYP2E1-null cells. Treated fatty acids were linoleic acid (LA:n-6, C18:2), arachidonic acid (AA:n-6, C20:4) and docosahexaenoic acid (DHA:n-3, C22:6). The cell survival rate was decreased corresponding to the degree of unsaturation (LA>AA $\cong$DHA) and to LPO production in E47 and 04 cells. The four or five unsaturation degree of fatty acids, AA and DHA, caused time- and dose-dependent cell death in E47 cells but not as much as in C34 (without CYP2E1), suggesting an important role of CYP2E1 in the DHA mediated damage. In the levels of lipid peroxides (LPO), AA also elevated LPO by 3- and 5- fold compared to DHA or LA treated E47 cells. However, AA did not increase LPO until 48 h incubation in C34 cells. In conclusion, the polyunsaturated fatty acids induced CYP2E1 induction might be changed by the elevated levels of lipid peroxide (LPO) and oxidative stress through the connection of CYP2E1 and degrees of unsaturated fatty acids.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권4호
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• pp.277-286
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• 2006

In the present study, I investigated the effects of N-methyl-D-aspartate (NMDA), arachidonic acid (AA), and Nitric Oxide Synthase Inhibitor (NOS-I), alone or in combination, on the viability of cultured primary normal human oral keratinocytes (NHOK). Specifically, we examined whether AA and NOS-I could protect primary NHOK from glutamate cytotoxicity. The purpose of this study was therefore the preliminary study for the examination of the interaction between these agents and NHOK in order to elucidate the mechanisms by which epithelial growth and regeneration are regulated. NHOK were obtained from gingival tissue of 20 individuals aged 20 to 29, and third passage (P3) cells were used for this study. Cell viability was measured by the MTT assay. NMDA and NNA, a calcium dependent NOS inhibitor, induced an initial increase in cell number, which subsequently decreased by the $7^{th}$ day. Low concentration of AA ($0.5\;{\mu}M$ & $1\;{\mu}M$) induced an increase in cell number while high concentrations of AA ($5\;{\mu}M$ & $10\;{\mu}M$) induced a decrease in cell number. The decrease in cell number induced by NMDA at the $7^{th}$ day was abolished by the addition of low concentrations of AA ($0.5\;{\mu}M$ & $1\;{\mu}M$) or NOS inhibitors. Low concentrations of AA ($0.5\;{\mu}M$ & $1\;{\mu}M$) or NOS inhibitors may protect the NHOK from NMDA induced cytotoxicity. These reactions might be related to the NMDA receptor in the cell and the change of the intracellular calcium ion concentration.

• 동의생리병리학회지
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• 제29권1호
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• pp.18-26
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• 2015

Akebiae Caulis is a galenical originated from Akebia quinata Decaisne species. It is commonly used in the treatment of oposiuria, inflammation, nociceptive and fever. Here, we investigated the effect of Akebiae Caulis extract (ACE) to protect hepatocyte against the malfunction of mitochondria and apoptosis. Arachidonic acid (AA)+iron promoted excessive reactive oxygen species (ROS) production and exerted a deleterious effect on mitochondria. Treatment with ACE protected hepatocytes from AA+iron-induced cytotoxicity, as shown by alterations in the protein levels related with apoptosis such as poly(ADP-ribose) polymerase, pro-caspase 3, Bcl-XL and Bcl-2. Moreover, AA+iron-induced $H_2O_2$ production, GSH depletion and mitochondrial dysfunction were alleviated by ACE pretreatment. As a potential molecular mechanism for the ACE-mediated cytoprotection, phosphorylation of AMP-activated protein kinase (AMPK), a key regulator in determining cell survival or death, was increased by ACE. Moreover, ACE treatment enhanced inactive phosphorylation of glycogen synthase kinase-$3{\beta}$ ($GSK3{\beta}$), downstream substrate kinase of AMPK. More importantly, ACE prevented a decrease in the $GSK3{\beta}$ phosphorylation derived by AA+iron, which might contribute to mitohondiral protection and cell survival. To further identify essential compounds in Akebiae Caulis for the protection of AA+iron-mediated cytotoxicity, we found that betulin in combination with hederagenin protected from AA+iron-induced mitochondrial dysfunction. Betulin+hederagenin treatment also increased inactive phosphorylation of $GSK3{\beta}$ in common with ACE. These results suggest that ACE protected hepatocytes against oxidative stress and mitochondrial dysfunction, which is mediated with inactive $GSK3{\beta}$ phosphorylation downstream of AMPK.

• 동아시아식생활학회지
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• 제23권3호
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• pp.311-319
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• 2013

The purpose of the present study is to investigate the effects of green tea catechin on microsomal phospholipase $A_2(PLA_2)$ activity and the arachidonic acid (AA) cascade in hearts of microwave exposed rats. Sprague-Dawley male rats weighing $100{\pm}10$ g were randomly assigned to one normal group and three microwave exposed groups. The microwave exposed groups were subdivided into three groups: catechin free diet (MW) group, 0.25% catechin (MW-0.25C group and 0.5% catechin (MW-0.5C) group according to the levels of dietary catechin supplementation. Rats were sacrificed $6^{th}$ day after microwave irradiations (2.45 GHz, 15 min). The heart microsome $PLA_2$ activity in the MW group was 130% greater than that of normal groups, whereas there was no significant difference between normal group and MW-0.25C, MW-0.5C group. The per- centage phosphatidyl ethanolamine (PE) hydrolyzed in the heart microsome in the MW was increased 54% by microwave irra- diation, whereas there was no significant difference between normal group and MW-0.5C group. The percentage phosphatidyl choline (PC) hydrolyzed in the heart microsome in the MW group was increased by 104% and by microwave irradiation, whereas there was no significant difference between normal group and MW-0.5C group. The formation of thromboxane $A_2(TXA_2)$ in the heart microsome was 70% greater in the MW group than in the normal group. However, the MW-0.25C and MW-0.5C group maintained the normal level. The formation of prostacyclin ($PGI_2$) in the heart microsome was 21% lower in the MW group than in the normal group, while that of MW-0.25C and MW-0.5C group were maintained in the normal group. The heart microsomal thiobarbituric acid reactive substances (TBARS) concentrations, as an index of lipid peroxide, were 71% greater in the MW group, as compared with normal group. However, the MW-0.25C and MW-0.5C group were 4.6% and 9.2% lower, respectively, than that of MW group. In conclusion, heart function appeared to be improved by green tea catechin supplementation due to its antithrombus action, which in return controls the AA cascade system.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.206.1-206.1
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• 2003

From methanol extract of Acanthopnanax senticosus, six platelet anti-aggregating compounds, chiisanogenin (1), chiisanoside (2), ursolic acid (3), oleanolic acid (4), b-sitosterol (5) and daucosterol (6) were isolated. All of the isolated compounds showed dose-dependent inhibitory activities to rat platelet aggregation induced by all the agonist employed. Compound 1 showed about 50 folds higher potency than acetylsalicylic acid (ASA) on U46619 induced platelet aggregation (IC$\sub$50/ : 6.21 ${\mu}$M) and 10 ∼ 20 folds higher effect than ASA on epinephrine and arachidonic acid (AA) induced aggregation (IC$\sub$50/ ; 2.50 and 4.81 ${\mu}$M, respectively). (omitted)

• Archives of Pharmacal Research
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• 제21권6호
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• pp.664-670
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• 1998

The role of intracellular $Ca^{2+}$, in the regulation of tumor cell proliferation by products of arachidonic acid (AA) metabolism was investigated using U-373 MG human as trocytoma cells. Treatment with nordihydroguaiaretic acid (NDGA), a lipoxygenase (LOX) inhibitor, or caffeic acid (CA), a specific 5-LOX inhibitor, suppressed proliferation of the tumor cells in a dose-dependent manner. However, indomethacin (indo), a cyclooxygenase (COX) inhibitor, did not significantly alter proliferation of the tumor cells. At anti-proliferative concentrations, NDGA and CA significantly inhibited intracellular $Ca^{2+}$ release induced by carbachol, a known intracelluar $Ca^{2+}$ agonist in the tumor cells. Exogenous administration of leukotriene $B_4(LTB_4)$, an AA metabolite of LOX pathway, enhanced proliferation of the tumor cells in a concentration-dependent fashion. In addition, $LTB_4$, induced intracelluar $Ca^{2+}$ release. Intracellular $Ca^{2+}$-inhibitors, such as an intracellular $Ca^{2+}$ chelator (BAPTA) and intracellular $Ca^{2+}$-release inhibitors (dantrolene and TMB-8), significantly blocked the LTB4-induced enhancement of cell proliferation and intracellular $Ca^{2+}$ release. These results suggest that LOX activity may be critical for cell proliferation of the human astrocytoma cells and that intracelluar $Ca^{2+}$ may play a major role in the mechanism of action of LOX.

• Biomolecules & Therapeutics
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• 제7권3호
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• pp.227-233
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• 1999

The effects of 2-bromo-3-(3,5-tert-butyl-4-hydroxylphenyl)-1,4-naphthalenedione(TPN2), a synthetic vitamin K derivative, on platelet aggregation and its action mechanisms were investigated in rat platelet. TPN2 inhibited the platelet aggregation induced by collagen($10\mu\textrm{g}$/ml), thrombin(0.1 U/ml), A23187($10\mu\textrm{M}$) and arachidonic acid($100\mu\textrm{M}$) in concentration-dependent manner with $IC_{50}$ values of 6.5$\pm$1.3, 59.3$\pm$4.5, 13.0$\pm$2.37 and 2.9$\pm$$1.0\mu\textrm{M}$, respectively. Collagen-induced serotonin release was significantly reduced by TPN2. The elevation of intracellular free $Ca^{2+}$ concentration ([$Ca^{2+}$]i) by collagen stimulation was greatly decreased by the pretreatment of TPN2, which was due to the inhibition of calcium release from intracellular store and influx from outside of the cell. TPN2 also significantly reduced the thromboxane $A_2$($TXA_2$) formation in a concentration-dependent manner. The collagen-induced arachidonic acid (AA) release in [$^3H$]-AA incorporated platelet, an indicative of the phospholipase $A_2$ activity, was decreased by TPN2 pretreatment. TPN2 significantly inhibited the activity of thromboxane synthase, but did not affect the cyclooxygenase activity. From these results. it is suggested that TPN2 exert its antiplatelet activity through the inhibition of the intra-cellular $Ca^{2+}$ mobilization and the decrease of the $TXA_2$ synthesis.

• Journal of Nutrition and Health
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• 제39권4호
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• pp.357-365
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• 2006

DHA, one of w-3 fatty acids, modulates cell growth or death though the changes of apoptotic signaling in human endothelial ECV304 cells. We investigated the effects of DHA on the changes of apoptotic signaling in human vascular endothelial ECV304 cells using lipid peroxidation (LPO) metabolites. LPO could be originated by dietary polyunsaturated fatty acids such as linoleic acid(LA), arachidonic acid(AA) and docosahexaenoic acid (DHA). DHA caused cell death of ECV304 cells compared to LA, AA or control as evidenced by changes in cell morphology and MTT assay. LPO levels was significantly elevated by 10 fold in DHA-treated ECV 304 cells and caspase-3 activity was increased by DHA corresponding to increasing incubation times compared to control. One of reasons of the cell death in DHA-treated ECV304 cells could be expected that caspase activity, marker for mitochondrial damages, might be triggered by the increasing LPO levels. Our results strongly indicated that DHA induced LPO production has an important role on apoptotic signaling pathway in ECV304 cells. LPO production in endothelial cells which was metabolized by oxidation of dietary PUFA, might be one of risk factors in the initial progression of atherosclerosis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권2호
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• pp.124-130
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• 2007

In the present study, I investigated the effects of N-methyl-D-aspartate (NMDA), arachidonic acid (AA), and Nitric Oxide Synthase Inhibitor (NOSI), alone or in combination, on the proliferation of cultured primary normal human oral keratinocytes (NHOK). The purpose of this study was therefore the preliminary study for the examination of the interaction between these agents and NHOK in order to elucidate the mechanisms by which epithelial growth and regeneration are regulated. NHOK were obtained from gingival tissue of 20 individuals aged 20 to 29, and third passage (P3) cells were used for this study. The DNA synthesis was measured by the BrdU assay. Addition of low concentration of AA ($1{\mu}M$) and high concentration of AA with NMDA group (NMDA+AA $10{\mu}M$) made DNA synthesis rate increase significantly at the early stage. Adding NNA ($10{\mu}M$) affected DNA synthesis rate to increase significantly in 4 hours. At the early stage, DNA synthesis was significantly active in the NOS-I with NMDA groups than in the control and the NMDA-only group, while it didn't become statistically meaningful in 24 hours. AA $1{\mu}M$ and NNA $10{\mu}M$ may induce the proliferation of the NHOK independently and NOS-I may induce the proliferation of the NHOK with NMDA. These reactions might be related to the NMDA receptor in the cell and the change of the intracellular calcium ion concentration.

• 대한본초학회지
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• 제30권6호
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• pp.7-15
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• 2015

Objectives : Rosa laevigata Michx. has been used for the treatment of renal disease in traditional Korean medicine. In this study, we investigated cytoprotective effect of R. laevigata water extract (RLE) against oxidative stress induced by arachidonic acid (AA) + iron.Methods : To evaluate the protective effects of RLE against AA + iron-induced oxidative stress in HepG2 cell, cell viability and changes on apoptosis-related proteins were assessed by MTT and immunoblot analyses. The effects of RLE on reduced glutathione level, production of reactive oxygen species and mitochondrial membrane potential were also monitored. Furthermore, to verify underlying molecular mechanism, NF-E2-related factor 2 (Nrf2) was examined by immunoblot analysis. Additionally, Nrf2 transactivation and its downstream target genes expression were also determined by reporter gene and realtime RT-PCR analyses.Results : RLE pretreatment (30-300 μg/ml) prevented cells from AA + iron-mediated cell death in a concentration dependent manner. In addition, 100 μg/ml RLE inhibited AA + iron-induced glutathione depletion, reactive oxygen species production and mitochondrial dysfunction. RLE accumulated nuclear Nrf2 and also transactivated Nrf2, which was evidenced by antioxidant response element- and glutathione S-transferase A2-driven luciferase activities and mRNA level of glutamate-cysteine ligase catalytic subunit, NAD(P)H:quinone oxidoreductase 1 and sestrin 2. Moreover, protective effect of RLE against AA + iron was abolished in Nrf2 knockout cells.Conclusions : These results indicate that RLE has the ability to protect hepatocyte against oxidative stress through Nrf2 activation.