151
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Tocotrienol ameliorates behavioral and biochemical alterations in the rat model of alcoholic neuropathy. Pain 2009; 145:129-35. [PMID: 19541419 DOI: 10.1016/j.pain.2009.05.028] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2009] [Revised: 05/27/2009] [Accepted: 05/28/2009] [Indexed: 11/21/2022]
Abstract
Chronic alcohol consumption produces a painful peripheral neuropathy for which there is no reliable successful therapy, which is mainly due to lack of understanding of its pathobiology. Alcoholic neuropathy is characterized by spontaneous burning pain, hyperalgesia (an exaggerated pain in response to painful stimuli) and allodynia (a pain evoked by normally innocuous stimuli). Chronic alcohol intake is known to decrease the nociceptive threshold with increased oxidative-nitrosative stress and release of proinflammatory cytokines coupled with activation of protein kinase C. The aim of the present study is to investigate the effect of both isoforms of vitamin E, alpha-tocopherol (100mg/kg; oral gavage) and tocotrienol (50, 100 and 200mg/kg; oral gavage) against alcohol-induced neuropathic pain in rats. Male Wistar rats, were administered 35% v/v ethanol (10 g/kg; oral gavage) for 10 weeks, and were treated with alpha-tocopherol and tocotrienol for the same duration. Ethanol-treated animals showed a significant decrease in nociceptive threshold as evident from decreased tail flick latency (thermal hyperalgesia) and decreased paw-withdrawal threshold in Randall-Sellito test (mechanical hyperalgesia) and von-Frey hair test (mechanical allodynia) along with the reduction in nerve glutathione and superoxide dismutase levels. TNF-alpha and IL-1beta levels were also significantly increased in both serum and sciatic nerve of ethanol-treated rats. Treatment with alpha-tocopherol and tocotrienol for 10 weeks significantly improved all the above-stated functional and biochemical deficits in a dose-dependent manner with more potent effects observed with tocotrienol. The study demonstrates the effectiveness of tocotrienol in attenuation of alcoholic neuropathy.
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152
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Choi Y, Lee J. Antioxidant and antiproliferative properties of a tocotrienol-rich fraction from grape seeds. Food Chem 2009. [DOI: 10.1016/j.foodchem.2008.11.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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153
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Tiwari V, Kuhad A, Chopra K. Suppression of neuro-inflammatory signaling cascade by tocotrienol can prevent chronic alcohol-induced cognitive dysfunction in rats. Behav Brain Res 2009; 203:296-303. [PMID: 19464322 DOI: 10.1016/j.bbr.2009.05.016] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 05/10/2009] [Accepted: 05/14/2009] [Indexed: 01/30/2023]
Abstract
Chronic alcohol intake is known to induce the selective neuronal damage associated with increase oxidative-nitrosative stress and activation of inflammatory cascade finally resulting in neuronal apoptosis and thus dementia. In the present study, we investigated the comparative effect of both the isoforms of vitamin E, alpha-tocopherol and tocotrienol against chronic alcohol-induced cognitive dysfunction in rats. Male Wistar rats were given ethanol (10g/kg; oral gavage) for 10 weeks, and treated with alpha-tocopherol and tocotrienol for the same duration. The learning and memory behavior was assessed using Morris water maze and elevated plus maze test. The rats were sacrificed at the end of 10th week and cytoplasmic fractions of cerebral cortex and hippocampus were prepared for the quantification of acetylcholinesterase activity, oxidative-nitrosative stress parameters, tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta). From the 6th week onwards, ethanol-treated rats showed significant increase in transfer latency in both the behavioral paradigms which was coupled with enhanced acetylcholinesterase activity, increased oxidative-nitrosative stress, TNF-alpha and IL-1beta levels in different brain regions of ethanol-treated rats. Co-administration of alpha-tocopherol as well as tocotrienol significantly and dose-dependently prevented these behavioral, biochemical and molecular changes in the brains of ethanol-treated rats. However, the effects were more pronounced with tocotrienol. The current study thus demonstrates the possible involvement of oxidative-nitrosative stress mediated activation of inflammatory cascade in chronic alcohol-induced cognitive dysfunction and also suggests the effectiveness of vitamin E isoforms, of which tocotrienol being more potent, in preventing the cognitive deficits associated with chronic alcohol consumption.
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Affiliation(s)
- Vinod Tiwari
- Pharmacology Research Laboratory, University Institute of Pharmaceutical Sciences UGC Center of Advanced Study, Panjab University, Chandigarh 160 014, India
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154
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Park HA, Khanna S, Rink C, Gnyawali S, Roy S, Sen CK. Glutathione disulfide induces neural cell death via a 12-lipoxygenase pathway. Cell Death Differ 2009; 16:1167-79. [PMID: 19373248 PMCID: PMC2990696 DOI: 10.1038/cdd.2009.37] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Oxidized glutathione (GSSG) is commonly viewed as a byproduct of GSH metabolism. The pathophysiological significance of GSSG per se remains poorly understood. Adopting a microinjection approach to isolate GSSG elevation within the cell, this work identifies that GSSG can trigger neural HT4 cell death via a 12-lipoxygenase (12-Lox)-dependent mechanism. In vivo, stereotaxic injection of GSSG into the brain caused lesion in wild-type mice but less so in 12-Lox knockout mice. Microinjection of graded amounts identified 0.5 mM as the lethal [GSSG]i in resting cells. Interestingly, this threshold was shifted to the left by 20-fold (0.025 mM) in GSH-deficient cells. This is important because tissue GSH lowering is commonly noted in the context of several diseases as well as in aging. Inhibition of GSSG reductase by BCNU is known to result in GSSG accumulation and caused cell death in a 12-Lox-sensitive manner. GSSG S-glutathionylated purified 12-Lox as well as in a model of glutamate-induced HT4 cell death in vitro where V5-tagged 12-Lox was expressed in cells. Countering glutamate-induced 12-Lox S-glutathionylation by glutaredoxin-1 overexpression protected against cell death. Strategies directed at improving or arresting cellular GSSG clearance may be effective in minimizing oxidative stress-related tissue injury or potentiating the killing of tumor cells, respectively.
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Affiliation(s)
- H-A Park
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH 43210, USA
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155
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Miyamoto K, Shiozaki M, Shibata M, Koike M, Uchiyama Y, Gotow T. Very-high-dose alpha-tocopherol supplementation increases blood pressure and causes possible adverse central nervous system effects in stroke-prone spontaneously hypertensive rats. J Neurosci Res 2009; 87:556-66. [PMID: 18942769 DOI: 10.1002/jnr.21851] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tocopherols and tocotrienols constitute the vitamin E family. Although alpha-tocotrienol is the most neuroprotective form of vitamin E proved to be effective against stroke, alpha-tocopherol is the most abundant in nature and is used most often for disease prevention/treatment. A recent metaanalysis of human studies suggested that alpha-tocopherol supplementation increases all-cause mortality. Therefore, we investigated the effects of alpha-tocopherol ( approximately 44 mg/kg body weight; equivalent to 2,600 mg/human/day) on the central nervous system (CNS) of stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP treated with high dose alpha-tocopherol had significantly higher blood pressure than untreated controls fed a basal diet that contained approximately 4 mg tocopherols/kg body weight, but neither group experienced a change in degree of lipid peroxidation in serum or CNS tissue. Biochemical/immunohistochemical analyses demonstrated that expressions of phosphorylated neurofilament H protein, glial fibrillary acidic protein and cathepsin D in the CNS tissue were significantly enhanced in alpha-tocopherol-supplemented rats, whereas expressions of SOD2 and Bcl-xL were diminished in response to alpha-tocopherol supplementation. Similarly, the frequency of cathepsin D-positive cells, corresponding mostly to microglial cells, was significantly increased in alpha-tocopherol-supplemented rats. Alpha-tocopherol supplementation also increased the number of lysosomes and lipofuscin granules in perikarya of both hippocampal pyramidal and Purkinje cells. Furthermore, alpha-tocopherol supplementation increased the frequency of glial filaments and lipofuscin granules in astrocytes and lysosomes in microglial cells that were frequently occupied with phagocytosed inclusion structures. The present results are the first to suggest that a very high dose of alpha-tocopherol supplementation increases blood pressure in SHRSP rats and influences the CNS tissue in a manner that seems adverse.
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Affiliation(s)
- Kaori Miyamoto
- Laboratory of Cell Biology, College of Nutrition, Koshien University, Takarazuka, Hyogo, Japan
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156
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Khanna S, Park HA, Sen CK, Golakoti T, Sengupta K, Venkateswarlu S, Roy S. Neuroprotective and antiinflammatory properties of a novel demethylated curcuminoid. Antioxid Redox Signal 2009; 11:449-68. [PMID: 18724833 PMCID: PMC2787730 DOI: 10.1089/ars.2008.2230] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2008] [Revised: 08/25/2008] [Accepted: 08/26/2008] [Indexed: 12/24/2022]
Abstract
A demethylated derivative of curcumin (DC; 67.8% bisdemethylcurcumin, 20.7% demethylmonodemethoxycurcumin, 5.86% bisdemethoxycurcumin, 2.58% demethylcurcumin) was prepared by using a 95% extract of curcumin (C(95); 72.2% curcumin, 18.8% monodemethoxycurcumin, 4.5% bisdemethoxycurcumin). DC increased glutathione and reduced reactive oxygen species (ROS) in HT4 neuronal cells. In a model of glutamate-induced death of HT4, DC was more effective than C(95) in neuroprotection. The protective effects of DC were retained even when DC was withdrawn from culture media after pretreatment. DC treatment, unlike an equal dose of C(95), completely spared glutamate-induced loss of cellular GSH. Both DC and C(95) prevented glutamate-induced elevation of cellular ROS but failed to attenuate glutamate-induced elevation of intracellular calcium. In human microvascular endothelial cells (HMECs) challenged with TNF-alpha, GeneChip analysis revealed that only a subcluster of 23 TNF-alpha-inducible genes were uniquely sensitive to C(95). In sharp contrast, 1,065 TNF-alpha-inducible genes were sensitive to DC but not to C(95), suggesting that DC was more effective in antagonizing the effects of TNF-alpha on HMECs. Functional analysis identified that the genes uniquely sensitive to DC belonged in four functional categories: cytokine-receptor interaction, focal adhesion, cell adhesion, and apoptosis. Real-time PCR as well as ELISA studies demonstrated that TNF-alpha-inducible CXCL10 and CXCL11 expression was sensitive to DC but not to C(95). Flow-cytometry studies recognized ICAM-1 and VCAM-1 as TNF-alpha-inducible adhesion molecules that were uniquely sensitive to DC. Taken together, DC exhibited promising neuroprotective and antiinflammatory properties that must be characterized in vivo.
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Affiliation(s)
- Savita Khanna
- Departments of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio
| | - Han-A Park
- Departments of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio
| | - Chandan K. Sen
- Departments of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio
| | | | | | | | - Sashwati Roy
- Departments of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio
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157
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Miyazawa T, Shibata A, Sookwong P, Kawakami Y, Eitsuka T, Asai A, Oikawa S, Nakagawa K. Antiangiogenic and anticancer potential of unsaturated vitamin E (tocotrienol). J Nutr Biochem 2009; 20:79-86. [DOI: 10.1016/j.jnutbio.2008.09.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 09/05/2008] [Accepted: 09/09/2008] [Indexed: 10/21/2022]
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158
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Shibata A, Nakagawa K, Sookwong P, Tsuduki T, Tomita S, Shirakawa H, Komai M, Miyazawa T. Tocotrienol Inhibits Secretion of Angiogenic Factors from Human Colorectal Adenocarcinoma Cells by Suppressing Hypoxia-Inducible Factor-1α. J Nutr 2008; 138:2136-42. [DOI: 10.3945/jn.108.093237] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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159
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Lim Y, Vasu VT, Valacchi G, Leonard S, Aung HH, Schock BC, Kenyon NJ, Li CS, Traber MG, Cross CE. Severe vitamin E deficiency modulates airway allergic inflammatory responses in the murine asthma model. Free Radic Res 2008; 42:387-96. [PMID: 18404538 DOI: 10.1080/10715760801976600] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Allergic asthma is a complex immunologically mediated disease associated with increased oxidative stress and altered antioxidant defenses. It was hypothesized that alpha-tocopherol (alpha-T) decreases oxidative stress and therefore its absence may influence allergic inflammatory process, a pathobiology known to be accompanied by oxidative stress. Therefore, selected parameters of allergic asthma sensitization and inflammation were evaluated following ovalbumin sensitization and re-challenge of alpha-T transfer protein (TTP) knock-out mice (TTP(-/-)) that have greatly reduced lung alpha-T levels (e.g.<5%) compared to their litter mate controls (TTP(+/+)). Results showed that severe alpha-T deficiency result in a blunted lung expression of IL-5 mRNA and IL-5 protein and plasma IgE levels compared with TTP(+/+) mice following immune sensitization and rechallenge, although lung lavage eosinophil levels were comparable in both genomic strains. It is concluded that the initial stimulation of immune responses by the TTP(-/-) mice were generally blunted compared to the TTP(+/+) mice, thus diminishing some aspects of subsequent allergic inflammatory processes.
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Affiliation(s)
- Yunsook Lim
- Department of Internal Medicine, Center for Comparative Lung Biology and Disease, School of Medicine, Davis, CA 95616, USA
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160
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Tumor anti-angiogenic effect and mechanism of action of δ-tocotrienol. Biochem Pharmacol 2008; 76:330-9. [DOI: 10.1016/j.bcp.2008.05.017] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 05/15/2008] [Accepted: 05/16/2008] [Indexed: 11/21/2022]
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161
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Prasad VVTS, Nithipatikom K, Harder DR. Ceramide elevates 12-hydroxyeicosatetraenoic acid levels and upregulates 12-lipoxygenase in rat primary hippocampal cell cultures containing predominantly astrocytes. Neurochem Int 2008; 53:220-9. [PMID: 18680775 DOI: 10.1016/j.neuint.2008.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 06/01/2008] [Accepted: 07/01/2008] [Indexed: 10/21/2022]
Abstract
We report, exogenous addition of ceramide significantly increases 12-hydroxyeicosatetraenoic acid [12-(S)-HETE] levels, in a dose-dependent manner. 12-(S)-HETE levels, in 20, 30 and 40microM ceramide exposed rat primary hippocampal cell cultures containing predominantly astrocytes and few neurons and other glial cells (the cultured hippocampal cells were predominantly astrocytes amounting to over 99% of total cells with few neurons and other glial cells) amounted to 207, 260 and 408% of the controls, respectively. However, dihydroceramide, an inactive analog of ceramide did not alter the levels of 12-(S)-HETE. Ceramide also increased the mRNA and protein expression, and activity of 12-lipoxygease (12-LOX) needed for the synthesis of 12(S)-HETE. These results indicate a possible link between ceramide and 12-LOX pathway. However, ceramide did not alter expression of 5-lipoxygenase (5-LOX), another member of the lipoxygenase family. However, ceramide upregulated expression of cytosolic phospholipase-A(2) (cPLA(2)) and cyclooxygenase-2 (COX-2). Further, ceramide caused a significant increase in the levels of reactive oxygen species (ROS). Ceramide-mediated generation of ROS was inhibited by baicalien but not by indomethacin. In addition, ceramide treated cells exhibited increased mRNA expression of DNA damage induced transcript3 (Ddit3). This report which demonstrate induction of pro-carcinogenic 12-LOX pathway by an anticancer ceramide, may be relevant to cancer biologists studying drug resistant tumors and devising potent anticancer therapeutic strategies to treat drug resistant tumors. These results indicate possibility of 12-LOX involvement in ceramide-mediated generation of ROS and cellular oxidative stress. Induction of 12-LOX pathway by ceramide may have implications in understanding pathophysiology of neurodegenerative diseases involving ROS generation and inflammation.
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162
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Ohnmacht S, Nava P, West R, Parker R, Atkinson J. Inhibition of oxidative metabolism of tocopherols with omega-N-heterocyclic derivatives of vitamin E. Bioorg Med Chem 2008; 16:7631-8. [PMID: 18656365 DOI: 10.1016/j.bmc.2008.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 07/02/2008] [Accepted: 07/06/2008] [Indexed: 12/11/2022]
Abstract
The oxidative metabolism of tocopherols and tocotrienols by monooxygenases is a key factor in the plasma and tissue clearance of forms of vitamin E other than alpha-tocopherol. It is well known that a commonly ingested form of vitamin E, gamma-tocopherol, has greatly reduced plasma half-life (faster clearance) than alpha-tocopherol. The tocotrienols are metabolized even faster than gamma-tocopherol. Both gamma-tocopherol and alpha- and delta-tocotrienol possess intriguing biological activities that are different from alpha-tocopherol, making them potentially of interest for therapeutic use. Unfortunately, the fast clearance of non-alpha-tocopherols from animal tissues is a significant hurdle to maximizing their effect(s) as dietary supplements. We report here the design and synthesis of N-heterocycle-containing analogues of alpha-tocopherol that act as inhibitors of Cyp4F2, the key monooxygenase responsible for omega-hydroxylation of the side chain of tocols. In particular, an omega-imidazole containing compound, 1, [(R)-2-(9-(1H-imidazol-1-yl)nonyl)-2,5,7,8-tetramethylchroman-6-ol] had an ED(50) for inhibition of gamma-CEHC production from gamma-tocopherol of approximately 1 nM when tested in HepG2 cells in culture. Furthermore, feeding of 1 to mice along with rapidly metabolized delta-tocopherol, resulted in a doubling of the delta-tocopherol/alpha-tocopherol ratio in liver (P<0.05). Thus, 1 may be a useful adjuvant to the therapeutic use of non-alpha-tocopherols.
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Affiliation(s)
- Stephan Ohnmacht
- Department of Chemistry and Centre for Biotechnology, Brock University, 500 Glenridge Avenue, St. Catharines, Ont., Canada L2S 3A1
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163
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Atkinson J, Epand RF, Epand RM. Tocopherols and tocotrienols in membranes: a critical review. Free Radic Biol Med 2008; 44:739-64. [PMID: 18160049 DOI: 10.1016/j.freeradbiomed.2007.11.010] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 11/09/2007] [Accepted: 11/12/2007] [Indexed: 12/14/2022]
Abstract
The familiar role of tocols (tocopherols and tocotrienols) as lipid-soluble chain-terminating inhibitors of lipid peroxidation is currently in the midst of a reinterpretation. New biological activities have been described for tocols that apparently are not dependent on their well-established antioxidant behaviour. These activities could well be real, but there remain large gaps in our understanding of the behaviour of tocols in membranes, especially when it comes to the alpha-, beta-, gamma-, delta-chroman methylation patterns and the seemingly special nature of tocotrienols. It is inappropriate to make conclusions and develop models based on in vivo (or cell culture) results with reference to in vitro measurements of antioxidant activity. When present in biological membranes, tocols will experience a large variation in the local composition of phospholipids and the presence of neutral lipids such as cholesterol, both of which would be expected to change the efficiency of antioxidant action. It is likely that tocols are not homogeneously dispersed in a membrane, but it is still not known whether any specific combination of lipid head group and acyl chains are conferred special protection from peroxidation, nor do we currently appreciate the structural role that tocols play in membranes. Tocols may enhance curvature stress or counteract similar stresses generated by other lipids such as lysolipids. This review will outline what is known about the location and behaviour of tocols in phospholipid bilayers. We will draw mainly from the biophysical literature, but will attempt to extend the discussion to biologically relevant phenomena when appropriate. We hope that it will assist researchers when designing new experiments and when critically assessing the results, in turn providing a more thorough understanding of the biochemistry of tocols.
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Affiliation(s)
- Jeffrey Atkinson
- Department of Chemistry and Centre for Biotechnology, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario, Canada.
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164
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Ohnmacht S, West R, Simionescu R, Atkinson J. Assignment of the 1H and 13C NMR of tocotrienols. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2008; 46:287-294. [PMID: 18236416 DOI: 10.1002/mrc.2176] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Vitamin E is a family of chromanols that vary by the degree of methylation of the chroman ring as well as the nature of the hydrophobic side chain at C2 that serves to anchor these lipids in biological membranes. The tocopherols contain saturated side chains, whereas the tocotrienols contain three sites of unsaturation and are derived from geranylgeranyl diphosphate. A growing interest in the unique biological activities of the tocotrienols has led us to begin syntheses of isotopically substituted forms and other derivatives that will be useful for probing the metabolism and membrane behavior of the tocotrienols. In order to be certain of our ability to selectively modify sites on the parent molecules it was necessary to make as complete an assignment of the 1H and 13C NMR as possible. Herein we report multidimensional NMR data (HSQC, COSY, ADEQUATE(1,1), C--H HMBC, and NOESY) that have allowed us to assign the identity of almost all the resonances for alpha-, beta-, gamma-, and delta-tocotrienol.
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Affiliation(s)
- Stephan Ohnmacht
- Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
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165
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Yoshida Y, Saito Y, Jones LS, Shigeri Y. Chemical reactivities and physical effects in comparison between tocopherols and tocotrienols: physiological significance and prospects as antioxidants. J Biosci Bioeng 2008; 104:439-45. [PMID: 18215628 DOI: 10.1263/jbb.104.439] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 10/25/2007] [Indexed: 02/05/2023]
Abstract
Vitamin E is a generic term for all tocopherol and tocotrienol derivatives. The most abundant and active form of vitamin E isoforms in vivo is alpha-tocopherol, but recently the roles of other forms of vitamin E have received renewed attention. In this review, we summarize the differences among alpha-, beta-, gamma-, delta-tocopherols and tocotrienols specifically regarding the following points; (i) their radical-scavenging efficacies and chemical reactivity with metal ions in solution, (ii) their physical effects at the liposomal membrane interior, and (iii) their protective effects against cell toxicity. Moreover, the physiological significance and future prospects for using vitamin E, especially tocotrienols, for the prevention and treatment of disease are discussed.
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Affiliation(s)
- Yasukazu Yoshida
- Human Stress Signal Research Center, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan
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166
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Pulse inhibition of histone deacetylases induces complete resistance to oxidative death in cortical neurons without toxicity and reveals a role for cytoplasmic p21(waf1/cip1) in cell cycle-independent neuroprotection. J Neurosci 2008; 28:163-76. [PMID: 18171934 DOI: 10.1523/jneurosci.3200-07.2008] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Histone deacetylase (HDAC) inhibitors are currently in human clinical trials as antitumor drugs because of their ability to induce cell dysfunction and death in cancer cells. The toxic effects of HDAC inhibitors are also apparent in cortical neurons in vitro, despite the ability of these agents to induce significant protection in the cells they do not kill. Here we demonstrate that pulse exposure of cortical neurons (2 h) in an in vitro model of oxidative stress results in durable neuroprotection without toxicity. Protection was associated with transcriptional upregulation of the cell cycle inhibitor, p21(waf1/cip1), both in this model and in an in vivo model of permanent ischemia. Transgenic overexpression of p21(waf1/cip1) in neurons can mimic the protective effect of HDAC inhibitors against oxidative stress-induced toxicity, including death induced by glutathione depletion or peroxide addition. The protective effect of p21(waf1/cip1) in the context of oxidative stress appears to be unrelated to its ability to act in the nucleus to inhibit cell cycle progression. However, although p21(waf1/cip1) is sufficient for neuroprotection, it is not necessary for HDAC inhibitor neuroprotection, because these agents can completely protect neurons cultured from p21(waf1/cip1)-null mice. Together these findings demonstrate (1) that pulse inhibition of HDACs in cortical neurons can induce neuroprotection without apparent toxicity; (2) that p21(waf1/cip1) is sufficient but not necessary to mimic the protective effects of HDAC inhibition; and (3) that oxidative stress in this model induces neuronal cell death via cell cycle-independent pathways that can be inhibited by a cytosolic, noncanonical action of p21(waf1/cip1).
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167
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Gamma-tocotrienol-induced apoptosis in human gastric cancer SGC-7901 cells is associated with a suppression in mitogen-activated protein kinase signalling. Br J Nutr 2007; 99:1247-54. [PMID: 18081943 DOI: 10.1017/s0007114507879128] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Tocotrienols have been shown to inhibit proliferation and induce apoptosis in cancer cells. However, the molecular mechanisms involved in tocotrienol-induced apoptosis are still unclear. In the present study, gamma-tocotrienol induced apoptosis in human gastric adenocarcinoma SGC-7901 cell line through down regulation of the extracellular signal-regulated kinase (ERK) signalling pathway. Furthermore, gamma-tocotrienol-induced apoptosis was accompanied by down regulation of Bcl-2, up regulation of Bax, activation of caspase-3, and subsequent poly (ADP-ribose) polymerase cleavage. These results indicated that up or down regulation of Bcl-2 family proteins play a major role in the initiation of gamma-tocotrienol-induced apoptosis as an activator of caspase-3. Gamma-tocotrienol also down regulated the activation of the Raf-ERK signalling pathway, and down regulated c-Myc by decreasing the expressions of Raf-1 and p-ERK1/2 proteins. The results suggest that key regulators in tocotrienol-induced apoptosis may be Bcl-2 families and caspase-3 in SGC-7901 cells through down regulation of the Raf-ERK signalling pathway.
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168
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Shichiri M, Takanezawa Y, Uchida K, Tamai H, Arai H. Protection of cerebellar granule cells by tocopherols and tocotrienols against methylmercury toxicity. Brain Res 2007; 1182:106-15. [DOI: 10.1016/j.brainres.2007.08.084] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 08/24/2007] [Accepted: 08/30/2007] [Indexed: 11/24/2022]
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169
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Xu X, Chua CC, Kong J, Kostrzewa RM, Kumaraguru U, Hamdy RC, Chua BHL. Necrostatin-1 protects against glutamate-induced glutathione depletion and caspase-independent cell death in HT-22 cells. J Neurochem 2007; 103:2004-14. [PMID: 17760869 DOI: 10.1111/j.1471-4159.2007.04884.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Glutamate, a major excitatory neurotransmitter in the CNS, plays a critical role in neurological disorders such as stroke and Parkinson's disease. Recent studies have suggested that glutamate excess can result in a form of cell death called glutamate-induced oxytosis. In this study, we explore the protective effects of necrostatin-1 (Nec-1), an inhibitor of necroptosis, on glutamate-induced oxytosis. We show that Nec-1 inhibits glutamate-induced oxytosis in HT-22 cells through a mechanism that involves an increase in cellular glutathione (GSH) levels as well as a reduction in reactive oxygen species production. However, Nec-1 had no protective effect on free radical-induced cell death caused by hydrogen peroxide or menadione, which suggests that Nec-1 has no antioxidant effects. Interestingly, the protective effect of Nec-1 was still observed when cellular GSH was depleted by buthionine sulfoximine, a specific and irreversible inhibitor of glutamylcysteine synthetase. Our study further demonstrates that Nec-1 significantly blocks the nuclear translocation of apoptosis-inducing factor (a marker of caspase-independent programmed cell death) and inhibits the integration of Bcl-2/adenovirus E1B 19 kDa-interacting protein 3 (a pro-death member of the Bcl-2 family) into the mitochondrial membrane. Taken together, these results demonstrate for the first time that Nec-1 prevents glutamate-induced oxytosis in HT-22 cells through GSH related as well as apoptosis-inducing factor and Bcl-2/adenovirus E1B 19 kDa-interacting protein 3-related pathways.
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Affiliation(s)
- Xingshun Xu
- Department of Pharmacology, and Cecile Cox Quillen Laboratory of Geriatric Research, James H. Quillen College of Medicine, East Tennessee State University, James H. Quillen Veterans Affairs Medical Center, Johnson City, Tennessee, USA
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170
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Nakagawa K, Shibata A, Yamashita S, Tsuzuki T, Kariya J, Oikawa S, Miyazawa T. In vivo angiogenesis is suppressed by unsaturated vitamin E, tocotrienol. J Nutr 2007; 137:1938-43. [PMID: 17634267 DOI: 10.1093/jn/137.8.1938] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Antiangiogenic therapy using drugs and food components is a recognized strategy for the prevention of various angiogenesis-mediated disorders such as tumor growth, diabetic retinopathy, and rheumatoid arthritis. Our preliminary cell culture studies, using both bovine aortic endothelial cells and human umbilical vein endothelial cells (HUVEC) on screening for food-derived antiangiogenic compounds, showed tocotrienol (T3), an unsaturated version of vitamin E, to be a potential angiogenic inhibitor. We therefore investigaged the in vivo antiangiogenic properties of T3 using 2 well-characterized angiogenic models [mouse dorsal air sac (DAS) assay and the chick embryo chorioallantoic membrane (CAM) assay]. In the DAS assay, the increased neovascularization (angiogenesis index, 4.8 +/- 0.6) in tumor cell-implanted mice was suppressed (angiogenesis index, 2.7 +/- 0.6) by dietary supplementation of 10 mg T3-rich oil/d (equivalent to 4.4 mg T3/d). In the CAM assay, T3 (500-1000 microg/egg) inhibited new blood vessel formation on the growing CAM and increased the frequency of avascular zone (36-50%). To evaluate the antiangiogenic mechanism, we conducted cell-culture studies and found that T3 significantly reduced fibroblast growth factor -induced proliferation, migration, and tube formation in HUVEC (P < 0.05), with delta-T3 having the highest activity. Western blot analysis revealed that delta-T3 suppressed the phosphorylation of phosophoinositide-dependent protein kinase (PDK) and Akt, and increased the phosphorylation of apoptosis signal-regulating kinase and p38 in fibroblast growth factor-treated HUVEC, indicating that the antiangiogenic effects of T3 are associated with changes in growth factor-dependent phosphatidylinositol-3 kinase /PDK/Akt signaling as well as induction of apoptosis in endothelial cells. Our findings suggest that T3 has potential as a therapeutic dietary supplement for preventing angiogenic disorders, and therefore future clinical study will be required to evaluate the efficacy and safety of T3.
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Affiliation(s)
- Kiyotaka Nakagawa
- Food and Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan
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171
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Abstract
Apoptosis mediates the precise and programmed natural death of neurons and is a physiologically important process in neurogenesis during maturation of the central nervous system. However, premature apoptosis and/or an aberration in apoptosis regulation is implicated in the pathogenesis of neurodegeneration, a multifaceted process that leads to various chronic disease states, such as Alzheimer's (AD), Parkinson's (PD), Huntington's (HD) diseases, amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), and diabetic encephalopathy. The current review focuses on two major areas (a) the fundamentals of apoptosis, which includes elements of the apoptotic machinery, apoptosis inducers, and emerging concepts in apoptosis research, and (b) apoptotic involvement in neurodegenerative disorders, neuroprotective treatment strategies/modalities, and the mechanisms of, and signaling in, neuronal apoptosis. Current and new experimental models for apoptosis research in neurodegenerative diseases are also discussed.
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Affiliation(s)
- Masahiro Okouchi
- Department of Internal Medicine and Bioregulation, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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172
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Khanna S, Roy S, Park HA, Sen CK. Regulation of c-Src activity in glutamate-induced neurodegeneration. J Biol Chem 2007; 282:23482-90. [PMID: 17569670 DOI: 10.1074/jbc.m611269200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
c-Src is heavily expressed in the brain and in human neural tissues. Our pursuit for characterization of the neuroprotective mechanisms of tocotrienols led to the first evidence demonstrating that rapid c-Src activation plays a central role in executing glutamate-induced neurodegeneration. It is now known that Src deficiency or blockade of Src activity in mice provides cerebral protection following stroke. Here, we sought to examine the mechanisms that regulate inducible c-Src activity in glutamate-challenged HT4 neural cells and primary cortical neurons. Knockdown of c-Src protected cells against glutamate-induced loss of viability. Consistently, microinjection of siRNA against c-Src protected cells against glutamate. Using overexpression and knockdown approaches, we noted that SHP-1 may be implicated in glutamate-induced c-Src activation. Following such activation, Cbp and caveolin-1 were phosphorylated and associated with Csk. Csk was translocated to the membrane where it down-regulated glutamate-induced c-Src activity by catalyzing the inhibitory phosphorylation of a tyrosine residue in c-Src. Findings of this study present a new paradigm that addresses the regulation of c-Src under neurodegenerative conditions.
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Affiliation(s)
- Savita Khanna
- Laboratory of Molecular Medicine, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio 43210, USA
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173
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Saito Y, Nishio K, Numakawa Y, Ogawa Y, Yoshida Y, Noguchi N, Niki E. Protective effects of 15-deoxy-Δ12,14-prostaglandin J2against glutamate-induced cell death in primary cortical neuron cultures: induction of adaptive response and enhancement of cell tolerance primarily through up-regulation of cellular glutathione. J Neurochem 2007; 102:1625-1634. [PMID: 17697048 DOI: 10.1111/j.1471-4159.2007.04701.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
There is increasing evidence to suggest that reactive oxygen species, including a variety of lipid oxidation products and other physiologically existing oxidative stimuli, can induce an adaptive response and enhance cell tolerance. In the present study, by using cultured cortical neurons, we investigated the effect of electrophilic lipids, such as 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) and 4-hydroxy-2-nonenal (4-HNE) against the cell death induced by H(2)O(2) and glutamate. Pre-treatment with both 15d-PGJ(2) and 4-HNE at sublethal concentrations resulted in a significant protective effect against oxidative stress, and 15d-PGJ(2), in particular, exhibited a complete protective effect against glutamate-induced neuronal cell death. Pre-treatment with 15d-PGJ(2) increased the intracellular glutathione (GSH) as well as the gene expression of glutamate-cysteine ligase (GCL), the rate-limiting enzyme of GSH synthesis. 15d-PGJ(2) protected cells from glutamate-induced GSH depletion, while the inhibition of cellular GSH synthesis by buthionine sulfoximine abolished the adaptive response induced by 15d-PGJ(2). These findings indicate that at low levels, 15d-PGJ(2) acts as a potent survival mediator against glutamate-induced insults via the induction of an adaptive response primarily through the up-regulation of the intracellular GSH synthesis.
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Affiliation(s)
- Yoshiro Saito
- Human Stress Signal Research Center (HSSRC), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, JapanLaboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, JapanDepartment of Environmental Systems Science, Faculty of Engineering, Doshisha University, Kyoto, Japan
| | - Keiko Nishio
- Human Stress Signal Research Center (HSSRC), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, JapanLaboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, JapanDepartment of Environmental Systems Science, Faculty of Engineering, Doshisha University, Kyoto, Japan
| | - Yumiko Numakawa
- Human Stress Signal Research Center (HSSRC), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, JapanLaboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, JapanDepartment of Environmental Systems Science, Faculty of Engineering, Doshisha University, Kyoto, Japan
| | - Yoko Ogawa
- Human Stress Signal Research Center (HSSRC), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, JapanLaboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, JapanDepartment of Environmental Systems Science, Faculty of Engineering, Doshisha University, Kyoto, Japan
| | - Yasukazu Yoshida
- Human Stress Signal Research Center (HSSRC), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, JapanLaboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, JapanDepartment of Environmental Systems Science, Faculty of Engineering, Doshisha University, Kyoto, Japan
| | - Noriko Noguchi
- Human Stress Signal Research Center (HSSRC), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, JapanLaboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, JapanDepartment of Environmental Systems Science, Faculty of Engineering, Doshisha University, Kyoto, Japan
| | - Etsuo Niki
- Human Stress Signal Research Center (HSSRC), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, JapanLaboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, JapanDepartment of Environmental Systems Science, Faculty of Engineering, Doshisha University, Kyoto, Japan
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174
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Bosetti F. Arachidonic acid metabolism in brain physiology and pathology: lessons from genetically altered mouse models. J Neurochem 2007; 102:577-86. [PMID: 17403135 PMCID: PMC2084377 DOI: 10.1111/j.1471-4159.2007.04558.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The arachidonic acid (AA) cascade involves the release of AA from the membrane phospholipids by a phospholipase A(2), followed by its subsequent metabolism to bioactive prostanoids by cyclooxygenases coupled with terminal synthases. Altered brain AA metabolism has been implicated in neurological, neurodegenerative, and psychiatric disorders. The development of genetically altered mice lacking specific enzymes of the AA cascade has helped to elucidate the individual roles of these enzymes in brain physiology and pathology. The roles of AA and its metabolites in brain physiology, with a particular emphasis on the phospholipase A(2)/cyclooxygenases pathway, are summarized, and the specific phenotypes of genetically altered mice relevant to brain physiology and neurotoxic models are discussed.
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Affiliation(s)
- Francesca Bosetti
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA.
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175
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Yoshida Y, Hayakawa M, Habuchi Y, Itoh N, Niki E. Evaluation of lipophilic antioxidant efficacy in vivo by the biomarkers hydroxyoctadecadienoic acid and isoprostane. Lipids 2007; 42:463-72. [PMID: 17476550 DOI: 10.1007/s11745-007-3043-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Accepted: 02/21/2007] [Indexed: 01/14/2023]
Abstract
The evaluation of antioxidant activity in vivo is difficult. In this study, the effects of dietary natural and synthetic antioxidants on the lipid peroxidation in mice were assessed using a biomarker, total hydroxyoctadecadienoic acid (tHODE). Biological samples such as plasma, erythrocytes, and tissues were first reduced and then saponified to convert various oxidation products of linoleates to tHODE. Subsequently, the absolute concentration of tHODE and its stereoisomer ratio, [9- and 13-(Z,E)-HODE)/[9- and 13-(E,E)-HODE], which is a measure of the hydrogen donor capacity of antioxidants, were determined by gas chromatography-mass spectrometry (GC-MS) analyses. These were then compared with total 8-iso-prostaglandin F(2alpha) (t8-iso-PGF(2alpha)) which was also assessed after reduction and saponification. Remarkable increases in tHODE and t8-iso-PGF(2alpha) levels were observed in the plasma, erythrocytes, liver, and brain of mice that were fed an alpha-tocopherol (alphaT)-stripped (E-free) diet for 1 month when compared with those of mice that were fed a standard diet (alphaT = 0.002 wt%). When mice were fed for 1 month on an E-free diet supplemented with a lipophilic antioxidant (0.04 wt%), namely, alphaT, alpha-tocotrienol (alphaT3), gamma-tocopherol (gammaT), or 2,3-dihydro-5-hydroxy-4,6-di-tert-butyl-2,2-dipentylbenzofuran (BO-653), a potent synthetic antioxidant, the increases of tHODE and t8-iso-PGF(2alpha) in the plasma, erythrocytes, liver, and brain were suppressed to the levels lower than those of mice fed a standard diet. The (Z,E/E,E) HODE ratio was decreased in the plasma and erythrocytes of mice fed the E-free diet when compared with that in mice fed the standard diet. This stereo-isomeric ratio was significantly recovered by the addition of alphaT and BO-653. These results show that the tHODE level and the (Z,E/E,E) HODE ratio are useful biomarkers for the assessment of antioxidant capacity in vivo and that the antioxidant capacity decreased in the order: BO-653 > alphaT3 >or= alphaT, gammaT, as assessed by tHODE levels from blood, liver, and brain.
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Affiliation(s)
- Yasukazu Yoshida
- Human Stress Signal Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka Ikeda, Osaka 563-8577, Japan.
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176
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Sen CK, Khanna S, Roy S. Tocotrienols in health and disease: the other half of the natural vitamin E family. Mol Aspects Med 2007; 28:692-728. [PMID: 17507086 PMCID: PMC2435257 DOI: 10.1016/j.mam.2007.03.001] [Citation(s) in RCA: 198] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 03/14/2007] [Accepted: 03/14/2007] [Indexed: 02/08/2023]
Abstract
Tocochromanols encompass a group of compounds with vitamin E activity essential for human nutrition. Structurally, natural vitamin E includes eight chemically distinct molecules: alpha-, beta-, gamma- and delta-tocopherol; and alpha-, beta-, gamma- and delta-tocotrienol. Symptoms caused by alpha-tocopherol deficiency can be alleviated by tocotrienols. Thus, tocotrienols may be viewed as being members of the natural vitamin E family not only structurally but also functionally. Palm oil and rice bran oil represent two major nutritional sources of natural tocotrienol. Taken orally, tocotrienols are bioavailable to all vital organs. The tocotrienol forms of natural vitamin E possesses powerful hypocholesterolemic, anti-cancer and neuroprotective properties that are often not exhibited by tocopherols. Oral tocotrienol protects against stroke-associated brain damage in vivo. Disappointments with outcomes-based clinical studies testing the efficacy of alpha-tocopherol need to be handled with caution and prudence recognizing the untapped opportunities offered by the other forms of natural vitamin E. Although tocotrienols represent half of the natural vitamin E family, work on tocotrienols account for roughly 1% of the total literature on vitamin E. The current state of knowledge warrants strategic investment into investigating the lesser known forms of vitamin E.
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Affiliation(s)
- Chandan K Sen
- Laboratory of Molecular Medicine, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH 43210, United States.
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177
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Kawakami Y, Tsuzuki T, Nakagawa K, Miyazawa T. Distribution of tocotrienols in rats fed a rice bran tocotrienol concentrate. Biosci Biotechnol Biochem 2007; 71:464-71. [PMID: 17284857 DOI: 10.1271/bbb.60524] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To examine the distribution of rice bran tocotrienol (T3), we gave rice bran T3 to rats after considering an acceptable daily intake of vitamin E for humans. Male SD rats (5 weeks of age) were fed for 3 weeks on a commercial diet containing 6.4 mg of vitamin E per 100 g wt and additively received vitamin E or the vehicle (vitamin E-free corn oil) by oral intubation. The animals were randomly divided into 4 groups depending on the type of test diet: control (vehicle), non-T3 (no T3 + 4.3 mg of tocopherol (TOC)/kg body weight (b.w.)/day), low-T3 (0.8 mg T3 + 3.5 mg TOC/kg b.w./day), and high-T3 (3.2 mg T3 + 1.1 mg TOC/kg b.w./day). The control rats and rats in the non-T3, low-T3, and high-T3 groups took 4.3 and 8.6 mg of vitamin E/kg b.w./day, respectively. Rice bran gamma-T3 was significantly distributed to the adipose tissue and increased from 1.1 to 10.2 nmol/g of adipose tissue according to the rice bran T3 intake.
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Affiliation(s)
- Yuki Kawakami
- Food and Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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178
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Tsuzuki W, Yunoki R, Yoshimura H. Intestinal Epithelial Cells Absorb γ-Tocotrienol Faster than α-Tocopherol. Lipids 2007; 42:163-70. [PMID: 17393222 DOI: 10.1007/s11745-007-3021-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 12/28/2006] [Indexed: 10/23/2022]
Abstract
To elucidate the transepithelial transport characteristics of lipophilic compounds, the cellular uptake of tocopherol and tocotrienol isomers were investigated in Caco2 cell monolayer models. These vitamin E isomers formed mixed micelles consisting of bile salts, lysophospholipids, free fatty acid, and 2-monoacylglycerols, then the micelles were supplied to Caco2 cells. The initial accumulation of tocotrienol isomers in Caco2 cells was larger than those of corresponding tocopherol isomers. There was little difference among the cellular accumulations of four tocopherol isomers. These findings suggested that the difference between the molecular structures of the C16 hydrocarbon chain tail in tocopherol and tocotrienol was strongly responsible for the rapid epithelial transport into the Caco2 cells membranes rather than the difference in the molecular structures of their chromanol head groups. Furthermore, the secretion of alpha-tocopherol and gamma-tocotrienol from Caco2 cells was investigated using Caco2 cells plated on a transwell. The time courses of their secretions from Caco2 cells showed that the initial secretion rate of gamma-tocotrienol was also larger than that of alpha-tocopherol. To investigate the intestinal uptake of alpha-tocopherol and gamma-tocotrienol in vivo, the mice were fed single doses of alpha-tocopherol or gamma-tocotrienol with triolein. The gamma-tocotrienol responded faster in plasma than alpha-tocopherol, although the maximal level of gamma-tocotrienol was lower than that of alpha-tocopherol. This suggested that the intestinal uptake properties of administered alpha-tocopherol and gamma-tocotrienol would characterize their plasma level transitions in mice.
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Affiliation(s)
- Wakako Tsuzuki
- National Food Research Institute, Tsukuba, Ibaraki, Japan.
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179
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Zingg JM. Modulation of signal transduction by vitamin E. Mol Aspects Med 2007; 28:481-506. [PMID: 17320164 DOI: 10.1016/j.mam.2006.12.009] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Accepted: 12/16/2006] [Indexed: 01/22/2023]
Abstract
The ability of vitamin E to modulate signal transduction and gene expression has been observed in numerous studies; however, the detailed molecular mechanisms involved are often not clear. The eight natural vitamin E analogues and synthetic derivatives affect signal transduction with different potency, possibly reflecting their different ability to interact with specific proteins. Vitamin E modulates the activity of several enzymes involved in signal transduction, such as protein kinase C, protein kinase B, protein tyrosine kinases, 5-, 12-, and 15-lipoxygenases, cyclooxygenase-2, phospholipase A2, protein phosphatase 2A, protein tyrosine phosphatase, and diacylglycerol kinase. Activation of some these enzymes after stimulation of cell surface receptors with growth factors or cytokines can be normalized by vitamin E. At the molecular level, the translocation of several of these enzymes to the plasma membrane is affected by vitamin E, suggesting that the modulation of protein-membrane interactions may be a common theme for vitamin E action. In this review the main effects of vitamin E on enzymes involved in signal transduction are summarized and the possible mechanisms leading to enzyme modulation evaluated. The elucidation of the molecular and cellular events affected by vitamin E could reveal novel strategies and molecular targets for developing similarly acting compounds.
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Affiliation(s)
- Jean-Marc Zingg
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.
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180
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Sen CK, Khanna S, Rink C, Roy S. Tocotrienols: the emerging face of natural vitamin E. VITAMINS AND HORMONES 2007; 76:203-61. [PMID: 17628176 PMCID: PMC3681510 DOI: 10.1016/s0083-6729(07)76008-9] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Natural vitamin E includes eight chemically distinct molecules: alpha-, beta-, gamma-, and delta-tocopherols and alpha-, beta-, gamma-, and delta-tocotrienols. More than 95% of all studies on vitamin E are directed toward the specific study of alpha-tocopherol. The other forms of natural vitamin E remain poorly understood. The abundance of alpha-tocopherol in the human body and the comparable efficiency of all vitamin E molecules as antioxidants led biologists to neglect the non-tocopherol vitamin E molecules as topics for basic and clinical research. Recent developments warrant a serious reconsideration of this conventional wisdom. The tocotrienol subfamily of natural vitamin E possesses powerful neuroprotective, anticancer, and cholesterol-lowering properties that are often not exhibited by tocopherols. Current developments in vitamin E research clearly indicate that members of the vitamin E family are not redundant with respect to their biological functions. alpha-Tocotrienol, gamma-tocopherol, and delta-tocotrienol have emerged as vitamin E molecules with functions in health and disease that are clearly distinct from that of alpha-tocopherol. At nanomolar concentration, alpha-tocotrienol, not alpha-tocopherol, prevents neurodegeneration. On a concentration basis, this finding represents the most potent of all biological functions exhibited by any natural vitamin E molecule. Recently, it has been suggested that the safe dose of various tocotrienols for human consumption is 200-1000/day. A rapidly expanding body of evidence supports that members of the vitamin E family are functionally unique. In recognition of this fact, title claims in publications should be limited to the specific form of vitamin E studied. For example, evidence for toxicity of a specific form of tocopherol in excess may not be used to conclude that high-dosage "vitamin E" supplementation may increase all-cause mortality. Such conclusion incorrectly implies that tocotrienols are toxic as well under conditions where tocotrienols were not even considered. The current state of knowledge warrants strategic investment into the lesser known forms of vitamin E. This will enable prudent selection of the appropriate vitamin E molecule for studies addressing a specific health need.
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Affiliation(s)
- Chandan K Sen
- Laboratory of Molecular Medicine, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio 43210, USA
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181
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Abstract
Vitamin E is a generic term that refers to a family of compounds that is further divided into two subgroups called tocopherols and tocotrienols. All natural forms of tocopherols and tocotrienols are potent antioxidants that regulate peroxidation reactions and controls free radical production within the body. However, it is now firmly established that many of the biological actions mediated by individual vitamin E isoforms are not dependent on their antioxidant activity. Furthermore, synthetic ether derivatives of vitamin E that no longer possess antioxidant activity also display a wide range of biological activities. One of the most intriguing therapeutic applications for natural vitamin E and vitamin E derivatives currently being investigated is their use as anticancer agents. Specific forms of vitamin E display potent apoptotic activity against a wide range of cancer cell types, while having little or no effect on normal cell function or viability. Experimental studies have also determined that the intracellular mechanisms mediating the apoptotic effects of specific vitamin E compounds display great diversity in different types of caner cells and has been found to restore multidrug resistant tumor cells sensitivity to chemotherapeutic agents. These findings strongly suggest that some natural and synthetic analogues of vitamin E can be used effectively as anticancer therapy either alone or in combination to enhance the therapeutic efficacy and reduce toxicity of other anticancer agents.
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Affiliation(s)
- Paul W Sylvester
- College of Pharmacy, University of Louisiana at Monroe, Monroe, Louisiana 71209, USA
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182
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Abstract
Tocotrienols, a group of Vitamin E stereoisomers, offer many health benefits including their ability to lower cholesterol levels, and provide anticancer and tumor-suppressive activities. Several recent studies determined the cardioprotective abilities of tocotrienols, although the number is only 1% compared to the study with tocopherols. Both in acute perfusion experiments and in chronic models, tocotrienols attenuate myocardial ischemia-reperfusion injury, artherosclerosis, and reduced ventricular arrythmias. Apart from the antioxidative role of tocotrienols, it appears that tocotrienols mediated cardioprotection is also achieved through the preconditioning-like effect, the best yet devised method of cardioprotection. Hence, tocotrienols likely fulfills the definition of a pharmacological preconditioning agent and give a tremendous opportunity to place tocotrienols as an important therapeutic option in cardiovascular system.
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Affiliation(s)
- Samarjit Das
- Cardiovascular Research Center, University of Connecticut School of Medicine, Farmington, Connecticut 06030, USA
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183
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Affiliation(s)
- Samarjit Das
- Cardiovascular Research Center, University of Connecticut School of Medicine Farmington, Connecticut 06030, USA
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184
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Patel V, Khanna S, Roy S, Ezziddin O, Sen CK. Natural vitamin E alpha-tocotrienol: retention in vital organs in response to long-term oral supplementation and withdrawal. Free Radic Res 2006; 40:763-71. [PMID: 16984003 DOI: 10.1080/10715760600672491] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The natural vitamin E tocotrienol (TCT) possesses biological properties not shared by tocopherols (TCP). Nanomolar alpha-TCT, not alpha-TCP, is potently neuroprotective (JBC 275:13049; 278:43508; Stroke 36:2258). The report that the affinity of TTP to bind (alpha-TCT is an order of magnitude lower than that for alpha-TCP questions the bioavailability of orally taken TCT to tissues. Oral supplementation of TCT for 3 years in nine generations of female and male rat was studied. Ten vital organs were examined. To gain insight into the turnover of alpha-TCT in tissues, a subset of supplemented rats was moved to vitamin E deficient diet for 7 weeks. Orally supplemented alpha-TCT was delivered to all vital organs including the brain and spinal cord in significant amounts. In organs such as the skin, adipose and gonads the maximum level of alpha-TCT achieved in response to supplementation was folds higher than baseline values of alpha-TCP in rats maintained on laboratory chow. Females had higher levels of alpha-TCT compared to matched tissues of corresponding males. To gain insight into how quickly alpha-TCT is metabolized in the tissues, washout of alpha-TCT from vital organs was examined. alpha-TCT accumulated in vital organs over more than 2 years was almost completely lost in less than 2 months when the supplementation was stopped. This is in sharp contrast with findings related to alpha-TCP retention. The ability of long-term oral supplementation to maintain and elevate alpha-TCT levels in vital organs together with the rapid elimination of the intact vitamin from all organs studied underscores the need for continuous oral supplementation of TCT.
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Affiliation(s)
- Viren Patel
- Laboratory of Molecular Medicine, Department of Surgery, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH 43210, USA
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185
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Abstract
BACKGROUND AND PURPOSE The natural product baicalein is a specific inhibitor of 12/15-lipoxygenase, but it also has antioxidant properties. The current study was designed to test if the neuroprotective properties of baicalein are related to its lipoxygenase inhibition. METHODS The presence of 12/15-lipoxygenase in the ischemic mouse brain was demonstrated by immunohistochemistry. A mouse model of transient middle cerebral artery occlusion was used to study lipoxygenase-dependent protection of the ischemic brain by baicalein. Rat primary neurons were subjected to oxidative stress in the presence or absence of baicalein. RESULTS In a mouse model of transient middle cerebral artery occlusion, 12/15-lipoxygenase is increased in the peri-infarct area surrounding the primary infarction, predominantly in neurons. Oxidative toxicity in primary rat neurons is reduced by baicalein. C57Bl6J mice are protected against transient focal ischemia by intraperitoneal injection of baicalein, and a similar degree of protection is seen in 12/15-lipoxygenase knockout mice compared with wild-type mice. In contrast, the 12/15-LOX knockout mice are not further protected by baicalein. CONCLUSIONS Baicalein protects against ischemia/reperfusion injury by inhibiting the 12/15-lipoxygenase pathway to neuronal cell death.
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Affiliation(s)
- Klaus van Leyen
- Stroke and Neurovascular Research Group, Department of Radiology, Massachusetts General Hospital, 149 13th St., R. 2401, Charlestown, MA 02129, USA.
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186
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Khanna S, Roy S, Parinandi NL, Maurer M, Sen CK. Characterization of the potent neuroprotective properties of the natural vitamin E alpha-tocotrienol. J Neurochem 2006; 98:1474-86. [PMID: 16923160 PMCID: PMC1847628 DOI: 10.1111/j.1471-4159.2006.04000.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The natural vitamin E tocotrienols possess properties not shared by tocopherols. Nanomolar alpha-tocotrienol, not alpha-tocopherol, is potently neuroprotective. On a concentration basis, this finding represents the most potent of all biological functions exhibited by any natural vitamin E molecule. We sought to dissect the antioxidant-independent and -dependent neuroprotective properties of alpha-tocotrienol by using two different triggers of neurotoxicity, homocysteic acid (HCA) and linoleic acid. Both HCA and linoleic acid caused neurotoxicity with comparable features, such as increased ratio of oxidized to reduced glutathione GSSG/GSH, raised intracellular calcium concentration and compromised mitochondrial membrane potential. Mechanisms underlying HCA-induced neurodegeneration were comparable to those in the path implicated in glutamate-induced neurotoxicity. Inducible activation of c-Src and 12-lipoxygenase (12-Lox) represented early events in that pathway. Overexpression of active c-Src or 12-Lox sensitized cells to HCA-induced death. Nanomolar alpha-tocotrienol was protective. Knock-down of c-Src or 12-Lox attenuated HCA-induced neurotoxicity. Oxidative stress represented a late event in HCA-induced death. The observation that micromolar, but not nanomolar, alpha-tocotrienol functions as an antioxidant was verified in a model involving linoleic acid-induced oxidative stress and cell death. Oral supplementation of alpha-tocotrienol to humans results in a peak plasma concentration of 3 microm. Thus, oral alpha-tocotrienol may be neuroprotective by antioxidant-independent as well as antioxidant-dependent mechanisms.
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Affiliation(s)
- Savita Khanna
- Laboratory of Molecular Medicine, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Colombus, Ohio 43210, USA
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187
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Alshuaib WB, Mathew MV. Vitamins C and E Modulate Neuronal Potassium Currents. J Membr Biol 2006; 210:193-8. [PMID: 16909341 DOI: 10.1007/s00232-006-0001-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2006] [Accepted: 03/30/2006] [Indexed: 11/30/2022]
Abstract
We investigated the effects of vitamins C and E on the delayed-rectifier potassium current (IK(DR)), which is important in repolarizing the membrane potential, and on the transient A-type potassium current (IK(A)), which regulates neuronal firing frequency. The whole-cell patch-clamp technique was used to measure the currents from cultured Drosophila neurons derived from embryonic neuroblasts. The membrane potential was stepped to different voltages between -40 and +60 mV from a holding potential of -80 mV. IK(DR) and IK(A) measured in the vitamin C-containing solution (IK(DR) 305 +/- 16 pA, IK(A) 11 +/- 2 pA) were smaller than those measured in the control solution (488 +/- 21 pA, IK(A )28 +/- 3 pA). By contrast, IK(DR) and IK(A) measured in the vitamin E-containing solution (IK(DR) 561 +/- 21 pA, IK(A )31 +/- 3 pA) were greater than those measured in the control solution (422 +/- 15 pA, 17 +/- 2 pA). These results indicate that vitamins C and E can modulate potassium current amplitudes and possibly lead to altered neuronal excitability.
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Affiliation(s)
- Waleed B Alshuaib
- Department of Physiology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait.
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188
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Chênevert R, Courchesne G, Pelchat N. Chemoenzymatic synthesis of both enantiomers of α-tocotrienol. Bioorg Med Chem 2006; 14:5389-96. [PMID: 16616508 DOI: 10.1016/j.bmc.2006.03.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Accepted: 03/20/2006] [Indexed: 11/20/2022]
Abstract
The stereoselective acylation of the achiral chromanedimethanol derivative 1 by vinyl acetate in the presence of Candida antarctica lipase B gave the (S)-monoester 2 in high enantiomeric purity (ee > or = 98%). Enzymatic hydrolysis of diesters of compound 1 failed to give (R)-monoester 2 in good yield and high ee. Thus, both enantiomers of alpha-tocotrienol were synthesized from the (S)-monoester 2.
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Affiliation(s)
- Robert Chênevert
- Département de chimie, faculté des sciences et de génie, Université Laval, Québec, Canada G1K 7P4.
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189
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Re DB, Nafia I, Melon C, Shimamoto K, Kerkerian-Le Goff L, Had-Aissouni L. Glutamate leakage from a compartmentalized intracellular metabolic pool and activation of the lipoxygenase pathway mediate oxidative astrocyte death by reversed glutamate transport. Glia 2006; 54:47-57. [PMID: 16673373 DOI: 10.1002/glia.20353] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Astrocytes have essential roles for neuron survival and function, so that their demise in neurodegenerative insults, such as ischemia, deserves attention. A major event of the cell death cascade in ischemia is the reversed operation of excitatory amino acid transporters (EAAT), releasing glutamate. Cytotoxicity is conventionally attributed to extracellular glutamate accumulation. We previously reported that mimicking such dysfunction by EAAT substrate inhibitors, whose uptake induces glutamate release by heteroexchange, triggers glutathione (GSH) depletion and oxidative death of differentiated astrocytes in culture. Here we demonstrate that astrocyte death, although correlated with glutamate release, is not resulting from high extracellular glutamate-mediated toxicity. L-glutamate per se was gliotoxic only at concentrations much higher than the maximum reached with the potent EAAT substrate inhibitor L-trans-pyrrolidine-2,4-dicarboxylate (PDC), and toxicity was lower. Moreover, high glutamate concentrations offered protection against PDC. Protection was also provided by L-aspartate, which is both transported by EAAT and metabolized into glutamate, and by inhibiting glutamine synthetase, which uses transported glutamate to synthesize glutamine. Neither D-aspartate, a metabolically inert EAAT substrate, nor compounds that can provide glutamate intracellularly but are not EAAT substrates offered protection. Interestingly, only the compounds providing protection prevented PDC-induced GSH depletion. These data strongly suggest that reversed uptake-mediated astrocyte death results from the leakage of glutamate from a compartmentalized intracellular metabolic pool specifically fuelled by EAAT, crucial for preserving GSH contents. In addition, we provide evidence for a minor contribution of the cystine-glutamate antiporter x(c) (-) but a major role of the 5-lipoxygenase pathway in this death mechanism.
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Affiliation(s)
- Diane B Re
- Interactions Cellulaires Neurodégénérescence et Neuroplasticité, IC2N, CNRS UMR 6186, Marseille, France
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190
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Aharoni-Simon M, Reifen R, Tirosh O. ROS-production-mediated activation of AP-1 but not NFkappaB inhibits glutamate-induced HT4 neuronal cell death. Antioxid Redox Signal 2006; 8:1339-49. [PMID: 16910781 DOI: 10.1089/ars.2006.8.1339] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Aside from their deleterious effect, reactive oxygen species (ROS) can function as small messenger molecules during physiologic processes. ROS have been shown to activate the transcription nuclear factor kappa B (NFkappaB) and activator protein 1 (AP-1). Exposure of HT4 neuronal cells to 10 mM glutamate results in cell death after 12 h. Here we show that glutamate treatment leads to an increase in ROS production and activation of AP-1, but not NFkappaB. 12-O-Tetradecanoylphorbol 13-acetate (TPA), an activator of protein kinase C and an inducer of NFkappaB and AP-1, protected the cells. This protective effect was preceded by increased production of ROS compared with glutamate alone, which was accompanied by a synergistic increase in AP-1, but not NFkappaB activity. We used all-trans-retinoic acid (ATRA), overexpression of retinoic acid receptor alpha (RARalpha) and a decoy oligonucleotide inclusion assay to suppress AP-1 activity. NFkappaB was inhibited by using a super suppressor (IkappaBalphaDeltaN-transfected cells). Inhibition of AP-1, but not NFkappaB resulted in increased cellular vulnerability to glutamate. Inhibition of AP-1 activity was coincident with a decrease in ROS production. Thus, although ROS are significant to the cell-death effect induced by glutamate, they also activate protective pathways mediated by increasing AP-1 activity, and not that of NFkappaB.
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Affiliation(s)
- Michal Aharoni-Simon
- The School of Nutritional Sciences, Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Israel
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191
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Khanna S, Roy S, Maurer M, Ratan RR, Sen CK. Oxygen-sensitive reset of hypoxia-inducible factor transactivation response: prolyl hydroxylases tune the biological normoxic set point. Free Radic Biol Med 2006; 40:2147-54. [PMID: 16785028 PMCID: PMC1489266 DOI: 10.1016/j.freeradbiomed.2006.02.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 02/02/2006] [Accepted: 02/16/2006] [Indexed: 12/16/2022]
Abstract
Cellular O(2) sensing enables physiological adjustments to variations in tissue pO(2). Under basal conditions, cells are adjusted to an O(2) environment biologically read as normoxia. Any sharp departure from that state of normoxia triggers O(2)-sensitive biological responses. The stabilization of hypoxia-inducible factor (HIF) signifies a robust biological readout of hypoxia. In the presence of sufficient O(2), HIF is hydroxylated and degraded. HIF prolyl hydroxylation is catalyzed by prolyl hydroxylase isoenzymes PHD1, 2, and 3. Using HT22 neurons stably transfected with a HIF reporter construct, we tested a novel hypothesis postulating that biological cells are capable of resetting their normoxic set point by O(2)-sensitive changes in PHD expression. Results of this study show that the pO(2) of the mouse brain cortex was 35 mm Hg or 5% O(2). Exposure of HT22, adjusted to growing in 20% O(2), to 5% O(2) resulted in HIF-driven transcription. However, cells adjusted to growing in 5% O(2) did not report hypoxia. Cells adjusted to growing in 30% O(2) reported hypoxia when acutely exposed to room air culture conditions. When grown under high O(2) conditions, cells reset their normoxic set point upward by down-regulating the expression of PHD1-3. When grown under low O(2) conditions, cells reset their normoxic set point downward by inducing the expression of PHD1-3. Exposure of mice in vivo to a hypoxic 10% O(2) environment lowered blood as well as brain pO(2). Such hypoxic exposure induced PHD1-3. Exposure of mice to a hyperoxic 50% O(2) ambience repressed the expression of PHD1-3, indicating that O(2)-sensitive regulation of PHD expression is effective in the brain in vivo. siRNA dependent knockdown of PHD expression revealed that O(2)-sensitive regulation of PHD may contribute to tuning the normoxic set point in biological cells.
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Affiliation(s)
- Savita Khanna
- From the Laboratory of Molecular Medicine, Davis Heart & Lung Research Institute, Department of Surgery, and
| | - Sashwati Roy
- From the Laboratory of Molecular Medicine, Davis Heart & Lung Research Institute, Department of Surgery, and
| | - Mariah Maurer
- From the Laboratory of Molecular Medicine, Davis Heart & Lung Research Institute, Department of Surgery, and
| | - Rajiv R Ratan
- Department of Neurology and Neuroscience, Burke/Cornell Medical Research Institute, Weill Medical College of Cornell, White Plains, NY 10605, USA
| | - Chandan K Sen
- From the Laboratory of Molecular Medicine, Davis Heart & Lung Research Institute, Department of Surgery, and
- Correspondence: Dr. Chandan K. Sen, 512 DHLRI, 473 W. 12 Avenue, Columbus, OH 43210, Tel. 614 247 7658; Fax 614 247 7818,
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192
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Musiek ES, Breeding RS, Milne GL, Zanoni G, Morrow JD, McLaughlin B. Cyclopentenone isoprostanes are novel bioactive products of lipid oxidation which enhance neurodegeneration. J Neurochem 2006; 97:1301-13. [PMID: 16638022 PMCID: PMC2881557 DOI: 10.1111/j.1471-4159.2006.03797.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidative stress and subsequent lipid peroxidation are involved in the pathogenesis of numerous neurodegenerative conditions, including stroke. Cyclopentenone isoprostanes (IsoPs) are novel electrophilic lipid peroxidation products formed under conditions of oxidative stress via the isoprostane pathway. These cyclopentenone IsoPs are isomeric to highly bioactive cyclopentenone prostaglandins, yet it has not been determined if these products are biologically active or are formed in the brain. Here we demonstrate that the major cyclopentenone IsoP isomer 15-A2t-IsoP potently induces apoptosis in neuronal cultures at submicromolar concentrations. We present a model in which 15-A2t-IsoP induced neuronal apoptosis involves initial depletion of glutathione and enhanced production of reactive oxygen species, followed by 12-lipoxygenase activation and phosphorylation of extracellular signal-regulated kinase 1/2 and the redox sensitive adaptor protein p66shc, which results in caspase-3 cleavage. 15-A2t-IsoP application also dramatically potentiates oxidative glutamate toxicity at concentrations as low as 100 nm, demonstrating the functional importance of these molecules in neurodegeneration. Finally, we employ novel mass spectrometric methods to show that cyclopentenone IsoPs are formed abundantly in brain tissue under conditions of oxidative stress. Together these findings suggest that cyclopentenone IsoPs may contribute to neuronal death caused by oxidative insults, and that their activity should perhaps be addressed when designing neuroprotective therapies.
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Affiliation(s)
- Erik S Musiek
- Department of Pharmacology, Venderbilt University, Nashville, Tennessee 37232, USA
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193
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Khosla P, Patel V, Whinter JM, Khanna S, Rakhkovskaya M, Roy S, Sen CK. Postprandial levels of the natural vitamin E tocotrienol in human circulation. Antioxid Redox Signal 2006; 8:1059-68. [PMID: 16771695 DOI: 10.1089/ars.2006.8.1059] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Compared to tocopherols, tocotrienols are poorly understood. The postabsorptive fate of tocotrienol isomers and their association with lipoprotein subfractions was examined. Normocholesterolemic women were subjected to an oral fat challenge supplemented with vitamin E (capsule containing 77 mg alpha-tocotrienol, 96 mg alpha-tocotrienol, 3 mg gamma-tocotrienol, 62 mg alpha-tocopherol, and 96 mg gamma-tocopherol). Plasma samples were collected at every 2 h intervals for up to 8 h following a one-time supplementation. Lipoproteins were measured by NMR spectroscopy, and subfractions of lipoproteins were isolated by density gradient ultracentrifugation. The maximal alpha-tocotrienol concentrations in supplemented individuals averaged approximately 3 microM in blood plasma, 1.7 microM in LDL, 0.9 microM in triglyceride-rich lipoprotein, and 0.5 microM in HDL. The peak plasma level corresponded to 12- to 30-fold more than the concentration of alpha-tocotrienol required to completely prevent stroke-related neurodegeneration. Tocotrienols were detected in the blood plasma and all lipoprotein subfractions studied postprandially.
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Affiliation(s)
- Pramod Khosla
- Department of Nutrition and Food Science, Wayne State University, Detroit, Michigan, USA
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194
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Numakawa Y, Numakawa T, Matsumoto T, Yagasaki Y, Kumamaru E, Kunugi H, Taguchi T, Niki E. Vitamin E protected cultured cortical neurons from oxidative stress-induced cell death through the activation of mitogen-activated protein kinase and phosphatidylinositol 3-kinase. J Neurochem 2006; 97:1191-202. [PMID: 16686696 DOI: 10.1111/j.1471-4159.2006.03827.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The role of vitamin E in the CNS has not been fully elucidated. In the present study, we found that pre-treatment with vitamin E analogs including alphaT (alpha-tocopherol), alphaT3 (alpha -tocotrienol), gammaT, and gammaT3 for 24 h prevented the cultured cortical neurons from cell death in oxidative stress stimulated by H2O2, while Trolox, a cell-permeable analog of alphaT, did not. The preventive effect of alphaT was dependent on de novo protein synthesis. Furthermore, we found that alphaT exposure induced the activation of both the MAP kinase (MAPK) and PI3 kinase (PI3K) pathways and that the alphaT-dependent survival effect was blocked by the inhibitors, U0126 (an MAPK pathway inhibitor) or LY294002 (a PI3K pathway inhibitor). Interestingly, the up-regulation of Bcl-2 (survival promoting molecule) was induced by alphaT application. The up-regulation of Bcl-2 did not occur in the presence of U0126 or LY294002, suggesting that alphaT-up-regulated Bcl-2 is mediated by these kinase pathways. These observations suggest that vitamin E analogs play an essential role in neuronal maintenance and survival in the CNS.
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Affiliation(s)
- Yumiko Numakawa
- Human Stress Signal Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Midorigaoka, Ikeda, Osaka, Japan.
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195
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Sen CK, Khanna S, Roy S. Tocotrienols: Vitamin E beyond tocopherols. Life Sci 2006; 78:2088-98. [PMID: 16458936 PMCID: PMC1790869 DOI: 10.1016/j.lfs.2005.12.001] [Citation(s) in RCA: 339] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Revised: 03/23/2005] [Accepted: 06/13/2005] [Indexed: 02/06/2023]
Abstract
In nature, eight substances have been found to have vitamin E activity: alpha-, beta-, gamma- and delta-tocopherol; and alpha-, beta-, gamma- and delta-tocotrienol. Yet, of all papers on vitamin E listed in PubMed less than 1% relate to tocotrienols. The abundance of alpha-tocopherol in the human body and the comparable efficiency of all vitamin E molecules as antioxidants, led biologists to neglect the non-tocopherol vitamin E molecules as topics for basic and clinical research. Recent developments warrant a serious reconsideration of this conventional wisdom. Tocotrienols possess powerful neuroprotective, anti-cancer and cholesterol lowering properties that are often not exhibited by tocopherols. Current developments in vitamin E research clearly indicate that members of the vitamin E family are not redundant with respect to their biological functions. alpha-Tocotrienol, gamma-tocopherol, and delta-tocotrienol have emerged as vitamin E molecules with functions in health and disease that are clearly distinct from that of alpha-tocopherol. At nanomolar concentration, alpha-tocotrienol, not alpha-tocopherol, prevents neurodegeneration. On a concentration basis, this finding represents the most potent of all biological functions exhibited by any natural vitamin E molecule. An expanding body of evidence support that members of the vitamin E family are functionally unique. In recognition of this fact, title claims in manuscripts should be limited to the specific form of vitamin E studied. For example, evidence for toxicity of a specific form of tocopherol in excess may not be used to conclude that high-dosage "vitamin E" supplementation may increase all-cause mortality. Such conclusion incorrectly implies that tocotrienols are toxic as well under conditions where tocotrienols were not even considered. The current state of knowledge warrants strategic investment into the lesser known forms of vitamin E. This will enable prudent selection of the appropriate vitamin E molecule for studies addressing a specific need.
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Affiliation(s)
- Chandan K Sen
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio 43210, USA.
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196
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Zhang Y, Wang H, Li J, Dong L, Xu P, Chen W, Neve RL, Volpe JJ, Rosenberg PA. Intracellular zinc release and ERK phosphorylation are required upstream of 12-lipoxygenase activation in peroxynitrite toxicity to mature rat oligodendrocytes. J Biol Chem 2006; 281:9460-70. [PMID: 16431921 DOI: 10.1074/jbc.m510650200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Peroxynitrite toxicity has been implicated in the pathogenesis of white matter injury. The mechanisms of peroxynitrite toxicity to oligodendrocytes (OLs), the major cell type of the white matter, are unknown. Using primary cultures of mature OLs that express myelin basic protein, we found that 3-morpholinosydnonimine, a peroxynitrite generator, caused toxicity to OLs. N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine, a zinc chelator, completely blocked peroxynitrite-induced toxicity. Use of FluoZin-3, a specific fluorescence zinc indicator, demonstrated the liberation of zinc from intracellular stores by peroxynitrite. Peroxynitrite caused the sequential activation of extracellular signal-regulated kinase 42/44 (ERK42/44), 12-lipoxygenase, and generation of reactive oxygen species, which were all dependent upon the intracellular release of zinc. The same cell death pathway was also activated when exogenous zinc was used. These results suggest that in addition to preventing the formation of peroxynitrite, useful strategies in preventing disease progression in pathologies in which peroxynitrite toxicity plays a critical role might include maintaining intracellular zinc homeostasis, blocking phosphorylation of ERK42/44, inhibiting activation of 12-lipoxygenase, and eliminating the accumulation of reactive oxygen species.
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Affiliation(s)
- Yumin Zhang
- Department of Neurology and Program in Neuroscience, Children's Hospital and Harvard Medical School, Boston, Mass 02115, USA
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197
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Clardy SL, Wang X, Zhao W, Liu W, Chase GA, Beard JL, True Felt B, Connor JR. Acute and chronic effects of developmental iron deficiency on mRNA expression patterns in the brain. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2006:173-96. [PMID: 17447428 DOI: 10.1007/978-3-211-33328-0_19] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Because of the multiple biochemical pathways that require iron, iron deficiency can impact brain metabolism in many ways. The goal of this study was to identify a molecular footprint associated with ongoing versus long term consequences of iron deficiency using microarray analysis. Rats were born to iron-deficient mothers, and were analyzed at two different ages: 21 days, while weaning and iron-deficient; and six months, after a five month iron-sufficient recovery period. Overall, the data indicate that ongoing iron deficiency impacts multiple pathways, whereas the long term consequences of iron deficiency on gene expression are more limited. These data suggest that the gene array profiles obtained at postnatal day 21 reflect a brain under development in a metabolically compromised setting that given appropriate intervention is mostly correctable. There are, however, long term consequences to the developmental iron deficiency that could underlie the neurological deficits reported for iron deficiency.
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Affiliation(s)
- S L Clardy
- Department of Neurosurgery, M.S. Hershey Medical Center, Hershey, USA
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198
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Bagchi D, Roy S, Patel V, He G, Khanna S, Ojha N, Phillips C, Ghosh S, Bagchi M, Sen CK. Safety and whole-body antioxidant potential of a novel anthocyanin-rich formulation of edible berries. Mol Cell Biochem 2006; 281:197-209. [PMID: 16328973 DOI: 10.1007/s11010-006-1030-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 07/18/2005] [Indexed: 10/25/2022]
Abstract
Edible berry extracts rich in anthocyanins possess a broad spectrum of therapeutic, pharmacologic and anti-carcinogenic properties. Six berry extracts (wild blueberry, bilberry, cranberry, elderberry, raspberry seeds and strawberry), singly and in combination, were studied in our laboratories for antioxidant efficacy, cytotoxic potential, cellular uptake and anti-angiogenic properties. Combinations of edible berry extracts were evaluated to develop a synergistic formula, OptiBerry, which exhibited high oxygen radical absorbance capacity (ORAC) value, low cytotoxicity and superior anti-angiogenic properties compared to the other combinations tested. The current study sought to determine the broad spectrum safety and antioxidant potential of OptiBerry in vivo. Acute oral LD(50) of OptiBerry was greater than 5 g/kg in rats. Acute dermal LD(50) of OptiBerry was greater than 2 g/kg. No changes in the body weight or adverse effects were observed following necropsy. Primary skin and eye irritation studies were conducted in New Zealand albino rabbits. OptiBerry was classified as slightly irritating to the skin (primary skin irritation index 0.3) and minimally irritating to the eye (maximum mean total score 6.0). The antioxidant potential of OptiBerry was investigated in rats and mice by assessing GSH redox status in tissues as well as by a unique state-of-the-art electron paramagnetic resonance (EPR) imaging of whole-body redox status. A clinically relevant hyperbaric oxygen (HBO) exposure system (2 atm, 2 h) was employed to study the antioxidant properties of OptiBerry. OptiBerry feeding (8 weeks) significantly prevented HBO-induced GSH oxidation in the lung and liver of vitamin E-deficient Sprague Dawley rats. Furthermore, OptiBerry-fed mice, when exposed to HBO, demonstrated significant protection in whole-body HBO-induced oxidation compared to the unfed controls by EPR imaging. Taken together, these results indicate that OptiBerry is reasonably safe and possess antioxidant properties.
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Affiliation(s)
- Debasis Bagchi
- Department of Pharmacy Sciences, School of Pharmacy and Health Professionals, Creighton University Medical Center, Omaha, NE 68178, USA.
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199
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Gu F, Netscher T, Atkinson J. 5-Trideuteromethyl-α-tocotrienol and 5-14CH3-α-tocotrienol as biological tracers of tocotrienols. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.1090] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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200
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Yun JS, Na HK, Park KS, Lee YH, Kim EY, Lee SY, Kim JI, Kang JH, Kim DS, Choi KH. Protective effects of Vitamin E on endocrine disruptors, PCB-induced dopaminergic neurotoxicity. Toxicology 2005; 216:140-6. [PMID: 16182432 DOI: 10.1016/j.tox.2005.08.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 08/02/2005] [Accepted: 08/02/2005] [Indexed: 10/25/2022]
Abstract
UNLABELLED The protective effect of an antioxidant, Vitamin E (dl-alpha-tocopherol, 100 mg/kg/day, 8 days p.o. in vivo and 10 and 50 microM in vitro) was tested against PCB-induced neurotoxicity. IN VIVO STUDIES Microdialysis was used to investigate changes in the striatal extracellular dopamine level and in p-nNOS expression in PCB-treated (Aroclor 1254, 10 microg/ml, 2 microl/min, 5 h; 6 microg was infused by microdialysis probe) rats. IN VITRO STUDIES Cell viability and levels of p-nNOS expression were observed in PCB-treated (Aroclor 1254, 5 microg/ml) immortalized dopaminergic cell line (CATH.a cells). RESULTS Treatment with PCB: (1) decreased the extracellular dopamine level in rat striatum, (2) increased p-nNOS expression both in rat striatal tissue and in CATH.a cells, (3) reduced the cell viability of, and (4) increased LDH release by CATH.a cells. However, Vitamin E showed a protective effect against PCB-induced toxicity and downregulation of the extracellular dopamine level. These results indicate that Vitamin E may have neuroprotective effects by inhibiting PCB-induced nNOS phosphorylation.
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Affiliation(s)
- Jae Suk Yun
- Division of General Pharmacology, National Institute of Toxicological Research, Korea Food and Drug Administration, 5 Nokbundong, Eunpyung-Gu, Seoul 122-704, South Korea
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