α-Tocopherol Increases the Intracellular Glutathione Level in HaCaT Keratinocytes

Hashimoto, Masaki; Okano, Yasuaki; Ochiai, Yasunobu; Obayashi, Kei; Akamatsu, Hirohiko; Sakurai, Hiromu

doi:10.1080/10715760210873

Cited by 40 publications

(26 citation statements)

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“…However, the amounts of aTP used in the above-mentioned experiments were orders of a magnitude higher than those possibly present in cells and therefore of no physiological relevance. An ''indirect'' antioxidant function of aTP via induction or regulation of enzymes involved in scavenging ROS and RNS was so far not observed; in fact, in contrast to aT [77], aTP was ineffective in elevating the intracellular level of the redox-active antioxidant glutathione (GSH). The observed inhibition by aTP of glutathione S-transferase omega 1 in vitro possibly plays a role in modulating the antiinflammatory effects of aT [78].…”

Section: Antioxidant Activity Of At and Atpmentioning

confidence: 94%

α‐Tocopheryl phosphate – An active lipid mediator?

Zingg

Meydani

Azzi

2010

Molecular Nutrition Food Res

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The vitamin E (alpha-tocopherol, alphaT) derivative, alpha-tocopheryl phosphate (alphaTP), is detectable in small amounts in plasma, tissues, and cultured cells. Studies done in vitro and in vivo suggest that alphaT can become phosphorylated and alphaTP dephosphorylated, suggesting the existence of enzyme(s) with alphaT kinase or alphaTP phosphatase activity, respectively. As a supplement in animal studies, alphaTP can reach plasma concentrations similar to alphaT and only a part is dephosphorylated; thus, alphaTP may act both as pro-vitamin E, but also as phosphorylated form of vitamin E with possibly novel regulatory activities. Many effects of alphaTP have been described: in the test tube alphaTP modulates the activity of several enzymes; in cell culture alphaTP affects proliferation, apoptosis, signal transduction, and gene expression; in animal studies alphaTP prevents atherosclerosis, ischemia/reperfusion injury, and induces hippocampal long-term potentiation. At the molecular level, alphaTP may act as a cofactor for enzymes, as an active lipid mediator similar to other phosphorylated lipids, or indirectly by altering membrane characteristics such as lipid rafts, fluidity, and curvature. In this review, the molecular and cellular activities of alphaTP are examined and the possible functions of alphaTP as a natural compound, cofactor and active lipid mediator involved in signal transduction and gene expression discussed.

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Section: Antioxidant Activity Of At and Atpmentioning

confidence: 94%

α‐Tocopheryl phosphate – An active lipid mediator?

Zingg

Meydani

Azzi

2010

Molecular Nutrition Food Res

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“…Antioxidant enzyme mRNA levels were estimated by the reverse transcription polymerase chain reaction (RT-PCR) method [19]. Cells were lysed in TRIzol by pipetting.…”

Section: Biochemical Analysismentioning

confidence: 99%

Resistance of Cultured Human Skin Fibroblasts from Old and Young Donors to Oxidative Stress and Their Glutathione Peroxidase Activity

Matsuo

Ikeda²,

Sugihara³

et al. 2004

Gerontology

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Background: It has been suggested that oxidative stress is involved in the aging process and that the resistance of animals to oxidative stress may decrease with advancing aging. However, there are only a limited number of reports of studies on the relationship between aging and resistance to oxidative stress. Objective: The aim of this work is to examine the relationship between the resistance of human skin fibroblasts to oxidative stress and donor age, and the relevance of antioxidant enzyme activities to this resistance. Methods: Percent cell survival was determined by the trypan blue exclusion test and the neutral red method. Superoxide dismutase activity was assayed by the method of Oyanagi, catalase activity by the method of Aebi, and glutathione peroxidase activity by the method of Flohé and Günzler. Reduced glutathione concentration was measured by the method of Griffith. Antioxidant enzyme mRNA levels were estimated by reverse transcription polymerase chain reactions (RT-PCR). Results: The percent survivals of cultured human skin fibroblasts, derived from young and old donors (referred to as young and old cells, respectively), under oxidative stress from hydrogen peroxide, linoleic acid hydroperoxide, or ultraviolet light B were examined. Old cells were more resistant to such oxidative stress than young cells. The activity of glutathione peroxidase was higher by 46.1% in old cells than in young cells, although there was no difference between their relative glutathione peroxidase mRNA levels. Further, there was no difference between their activities of copper/zinc superoxide dismutase, manganese superoxide dismutase, or catalase. However, the relative mRNA levels of copper/zinc superoxide dismutase and manganese superoxide dismutase were lower by 13.9 and 20.9% in old cells than in young cells, respectively, while there was no difference between the levels of catalase. Conclusions: These results suggest that old cells are more resistant to oxidative stress than young cells, presumably because of an increase in cellular glutathione peroxidase activity.

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“…Tocopherols, tocotrienols, and carotenes in RPO are able to quench peroxyl radicals generated by t-BHP biotransformation by donating hydrogen from their phenolic hydroxyl group to the peroxyl radical thereby forming a stable radical species [113] and thus spare GSH and protect the cells from oxidative stress. RPO could also increase the biosynthesis of GSH because previous in vitro and in vivo studies have indicated that -tocopherol [114,115] and -carotene [116,117] increased intracellular GSH levels by upregulating the mRNA expression of -GCS.…”

Section: Discussionmentioning

confidence: 99%

Protective Effects of Rooibos (Aspalathus Linearis) and/or Red Palm Oil (Elaeis Guineensis) Supplementation on Tert-Butyl Hydroperoxide-Induced Oxidative Hepatotoxicity in Wistar Rats

Ajuwon

Katengua-Thamahane

Rooyen

et al. 2012

Free Radical Biology and Medicine

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The possible protective effects of an aqueous rooibos extract (Aspalathus linearis), red palm oil (RPO) (Elaeis guineensis), or their combination on tert-butyl-hydroperoxide-(t-BHP-)induced oxidative hepatotoxicity in Wistar rats were investigated. tert-butyl hydroperoxide caused a significant ( < 0.05) elevation in conjugated dienes (CD) and malondialdehyde (MDA) levels, significantly ( < 0.05) decreased reduced glutathione (GSH) and GSH : GSSG ratio, and induced varying changes in activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase in the blood and liver. This apparent oxidative injury was associated with histopathological changes in liver architecture and elevated levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Supplementation with rooibos, RPO, or their combination significantly ( < 0.05) decreased CD and MDA levels in the liver and reduced serum level of ALT, AST, and LDH. Likewise, changes observed in the activities of antioxidant enzymes and impairment in redox status in the erythrocytes and liver were reversed. The observed protective effects when rooibos and RPO were supplemented concomitantly were neither additive nor synergistic. Our results suggested that rooibos and RPO, either supplemented alone or combined, are capable of alleviating t-BHP-induced oxidative hepatotoxicity, and the mechanism of this protection may involve inhibition of lipid peroxidation and modulation of antioxidants enzymes and glutathione status.

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α-Tocopherol Increases the Intracellular Glutathione Level in HaCaT Keratinocytes

Cited by 40 publications

References 0 publications

α‐Tocopheryl phosphate – An active lipid mediator?

α‐Tocopheryl phosphate – An active lipid mediator?

Resistance of Cultured Human Skin Fibroblasts from Old and Young Donors to Oxidative Stress and Their Glutathione Peroxidase Activity

Protective Effects of Rooibos (Aspalathus Linearis) and/or Red Palm Oil (Elaeis Guineensis) Supplementation on Tert-Butyl Hydroperoxide-Induced Oxidative Hepatotoxicity in Wistar Rats

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