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Oliveras-López MJ, Innocenti M, Martín Bermudo F, López-García de la Serrana H, Mulinacci N. Effect of extra virgin olive oil on glycaemia in healthy young subjects. EUR J LIPID SCI TECH 2012. [DOI: 10.1002/ejlt.201100368] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Huang Z, Rose AH, Hoffmann PR. The role of selenium in inflammation and immunity: from molecular mechanisms to therapeutic opportunities. Antioxid Redox Signal 2012; 16:705-43. [PMID: 21955027 PMCID: PMC3277928 DOI: 10.1089/ars.2011.4145] [Citation(s) in RCA: 533] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important role in inflammation and immunity. Adequate levels of Se are important for initiating immunity, but they are also involved in regulating excessive immune responses and chronic inflammation. Evidence has emerged regarding roles for individual selenoproteins in regulating inflammation and immunity, and this has provided important insight into mechanisms by which Se influences these processes. Se deficiency has long been recognized to negatively impact immune cells during activation, differentiation, and proliferation. This is related to increased oxidative stress, but additional functions such as protein folding and calcium flux may also be impaired in immune cells under Se deficient conditions. Supplementing diets with above-adequate levels of Se can also impinge on immune cell function, with some types of inflammation and immunity particularly affected and sexually dimorphic effects of Se levels in some cases. In this comprehensive article, the roles of Se and individual selenoproteins in regulating immune cell signaling and function are discussed. Particular emphasis is given to how Se and selenoproteins are linked to redox signaling, oxidative burst, calcium flux, and the subsequent effector functions of immune cells. Data obtained from cell culture and animal models are reviewed and compared with those involving human physiology and pathophysiology, including the effects of Se levels on inflammatory or immune-related diseases including anti-viral immunity, autoimmunity, sepsis, allergic asthma, and chronic inflammatory disorders. Finally, the benefits and potential adverse effects of intervention with Se supplementation for various inflammatory or immune disorders are discussed.
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Affiliation(s)
- Zhi Huang
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
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53
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Selenium and its' role in the maintenance of genomic stability. Mutat Res 2012; 733:100-10. [PMID: 22234051 DOI: 10.1016/j.mrfmmm.2011.12.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 12/11/2011] [Accepted: 12/22/2011] [Indexed: 02/07/2023]
Abstract
Selenium (Se) is an essential micronutrient for humans, acting as a component of the unusual amino acids, selenocysteine (Se-Cys) and selenomethionine (Se-Met). Where Se levels are low, the cell cannot synthesise selenoproteins, although some selenoproteins and some tissues are prioritised over others. Characterised functions of known selenoproteins, include selenium transport (selenoprotein P), antioxidant/redox properties (glutathione peroxidases (GPxs), thioredoxin reductases and selenoprotein P) and anti-inflammatory properties (selenoprotein S and GPx4). Various forms of Se are consumed as part of a normal diet, or as a dietary supplement. Supplementation of tissue culture media, animal or human diets with moderate levels of certain Se compounds may protect against the formation of DNA adducts, DNA or chromosome breakage, and chromosome gain or loss. Protective effects have also been shown on mitochondrial DNA, and on telomere length and function. Some of the effects of Se compounds on gene expression may relate to modulation of DNA methylation or inhibition of histone deacetylation. Despite a large number of positive effects of selenium and selenoproteins in various model systems, there have now been some human clinical trials that have shown adverse effects of Se supplementation, according to various endpoints. Too much Se is as harmful as too little, with animal models showing a "U"-shaped efficacy curve. Current recommended daily allowances differ among countries, but are generally based on the amount of Se necessary to saturate GPx enzymes. However, increasing evidence suggests that other enzymes may be more important than GPx for Se action, that optimal levels may depend upon the form of Se being ingested, and vary according to genotype. New paradigms, possibly involving nutrigenomic tools, will be necessary to optimise the forms and levels of Se desirable for maximum protection of genomic stability in all humans.
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Krehl S, Loewinger M, Florian S, Kipp AP, Banning A, Wessjohann LA, Brauer MN, Iori R, Esworthy RS, Chu FF, Brigelius-Flohé R. Glutathione peroxidase-2 and selenium decreased inflammation and tumors in a mouse model of inflammation-associated carcinogenesis whereas sulforaphane effects differed with selenium supply. Carcinogenesis 2011; 33:620-8. [PMID: 22180572 DOI: 10.1093/carcin/bgr288] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Chronic inflammation and selenium deficiency are considered as risk factors for colon cancer. The protective effect of selenium might be mediated by specific selenoproteins, such as glutathione peroxidases (GPx). GPx-1 and -2 double knockout, but not single knockout mice, spontaneously develop ileocolitis and intestinal cancer. Since GPx2 is induced by the chemopreventive sulforaphane (SFN) via the nuclear factor E2-related factor 2 (Nrf2)/Keap1 system, the susceptibility of GPx2-KO and wild-type (WT) mice to azoxymethane and dextran sulfate sodium (AOM/DSS)-induced colon carcinogenesis was tested under different selenium states and SFN applications. WT and GPx2-KO mice were grown on a selenium-poor, -adequate or -supranutritional diet. SFN application started either 1 week before (SFN4) or along with (SFN3) a single AOM application followed by DSS treatment for 1 week. Mice were assessed 3 weeks after AOM for colitis and Nrf2 target gene expression and after 12 weeks for tumorigenesis. NAD(P)H:quinone oxidoreductases, thioredoxin reductases and glutathione-S-transferases were upregulated in the ileum and/or colon by SFN, as was GPx2 in WT mice. Inflammation scores were more severe in GPx2-KO mice and highest in selenium-poor groups. Inflammation was enhanced by SFN4 in both genotypes under selenium restriction but decreased in selenium adequacy. Total tumor numbers were higher in GPx2-KO mice but diminished by increasing selenium in both genotypes. SFN3 reduced inflammation and tumor multiplicity in both Se-adequate genotypes. Tumor size was smaller in Se-poor GPx2-KO mice. It is concluded that GPx2, although supporting tumor growth, inhibits inflammation-mediated tumorigenesis, but the protective effect of selenium does not strictly depend on GPx2 expression. Similarly, SFN requires selenium but not GPx2 for being protective.
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Affiliation(s)
- Susanne Krehl
- Department of Biochemistry of Micronutrients, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
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Kipp AP, Banning A, van Schothorst EM, Méplan C, Coort SL, Evelo CT, Keijer J, Hesketh J, Brigelius-Flohé R. Marginal selenium deficiency down-regulates inflammation-related genes in splenic leukocytes of the mouse. J Nutr Biochem 2011; 23:1170-7. [PMID: 22137268 DOI: 10.1016/j.jnutbio.2011.06.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 06/21/2011] [Accepted: 06/29/2011] [Indexed: 01/14/2023]
Abstract
Moderate selenium deficiency may lead to an impaired capacity to cope with health challenges. Functional effects of suboptimal selenium intake are not fully known, and biomarkers for an insufficient selenium supply are inadequate. We therefore fed mice diets of moderately deficient or adequate selenium intake for 6 weeks. Changes in global gene expression were monitored by microarray analysis in splenic leukocytes. Genes for four selenoproteins, Sepw1, Gpx1, Selh and Sep15, were the most significantly down-regulated in moderate selenium deficiency, and this was confirmed by quantitative polymerase chain reaction (qPCR). Classification of significantly affected genes revealed that processes related to inflammation, heme biosynthesis, DNA replication and transcription, cell cycle and transport were affected by selenium restriction. Down-regulation by moderate selenium deficiency of specific genes involved in inflammation and heme biosynthesis was confirmed by qPCR. Myeloperoxidase and lysozyme activities were decreased in selenium-restricted leukocytes, providing evidence for functional consequences. Genes for 31 nuclear factor (NF)-κB targets were down-regulated in moderate selenium deficiency, indicating an impaired NF-κB signaling. Together, the observed changes point to a disturbance in inflammatory response. The selenoproteins found here to be sensitive to selenium intake in murine leukocytes might also be useful as biomarkers for a moderate selenium deficiency in humans.
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Affiliation(s)
- Anna P Kipp
- Department Biochemistry of Micronutrients, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
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Reszka E, Jablonska E, Gromadzinska J, Wasowicz W. Relevance of selenoprotein transcripts for selenium status in humans. GENES AND NUTRITION 2011; 7:127-37. [PMID: 21898179 PMCID: PMC3316749 DOI: 10.1007/s12263-011-0246-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 08/19/2011] [Indexed: 11/19/2022]
Abstract
The most commonly used methods for assessing the selenium (Se) status in humans involve analysis of Se concentration, selenoprotein activity, and concentration in the blood and its compartments. Recently, it has been suggested that the expression of selenoprotein mRNA in circulating blood leukocytes could differently reflect Se status, due to prioritization of specific selenoprotein synthesis in response to dietary Se supply. Whereas the Se levels required for optimization of selenoprotein P level and plasma glutathione peroxidise activity are well known, estimation of Se level that is required for maximal mRNA expression of selenoprotein in humans is the subject of current investigations. Studies on rats suggest that whole blood selenoprotein mRNA level can be used as the relevant molecular biomarker for assessing Se status, and suboptimal Se intake may be sufficient to achieve effective expression. Human studies, however, did not confirm this hypothesis. According to studies on rodents and humans discussed in this review, it appears that suboptimal Se intake may be sufficient to satisfy molecular requirements of Se and it is lower than current recommended dietary intake in humans. The use of selenoprotein transcripts as a molecular biomarker of Se status requires further studies on a large group of healthy individuals with different baseline Se, including data regarding genetic polymorphism of selenoproteins and data regarding potential modifiers of Se metabolism.
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Affiliation(s)
- Edyta Reszka
- Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, 8 Teresy St., 91-348, Lodz, Poland
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van Schothorst EM, Bunschoten A, Verlinde E, Schrauwen P, Keijer J. Glycemic index differences of high-fat diets modulate primarily lipid metabolism in murine adipose tissue. Physiol Genomics 2011; 43:942-9. [DOI: 10.1152/physiolgenomics.00042.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A low vs. high glycemic index of a high-fat (HF) diet (LGI and HGI, respectively) significantly retarded adverse health effects in adult male C57BL/6J mice, as shown recently (Van Schothorst EM, Bunschoten A, Schrauwen P, Mensink RP, Keijer J. FASEB J 23: 1092–1101, 2009). The LGI diet enhanced whole body insulin sensitivity and repressed HF diet-induced body and white adipose tissue (WAT) weight gain, resulting in significantly reduced serum leptin and resistin levels and increased adiponectin levels. We questioned how WAT is modulated and characterized the molecular mechanisms underlying the glycemic index-mediated effects using whole genome microarrays. This showed that the LGI diet mainly exerts its beneficial effects via substrate metabolism, especially fatty acid metabolism. In addition, cell adhesion and cytoskeleton remodeling showed reduced expression, in line with lower WAT mass. An important transcription factor showing enhanced expression is PPAR-γ. Furthermore, serum levels of triglycerides, total cholesterol, and HDL- and LDL-cholesterol were all significantly reduced by LGI diet, and simultaneously muscle insulin sensitivity was significantly increased as analyzed by protein kinase B/Akt phosphorylation. Cumulatively, even though these mice were fed an HF diet, the LGI diet induced significantly favorable changes in metabolism in WAT. These effects suggest a partial overlap with pharmacological approaches by thiazolidinediones to treat insulin resistance and statins for hypercholesterolemia. It is therefore tempting to speculate that such a dietary approach might beneficially support pharmacological treatment of insulin resistance or hypercholesterolemia in humans.
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Affiliation(s)
- Evert M. van Schothorst
- Top Institute Food and Nutrition
- Human and Animal Physiology, Wageningen University, Wageningen; and
| | - Annelies Bunschoten
- Top Institute Food and Nutrition
- Human and Animal Physiology, Wageningen University, Wageningen; and
| | - Eline Verlinde
- Human and Animal Physiology, Wageningen University, Wageningen; and
| | - Patrick Schrauwen
- Top Institute Food and Nutrition
- Department of Human Biology, Maastricht University, Maastricht, The Netherlands
| | - Jaap Keijer
- Top Institute Food and Nutrition
- Human and Animal Physiology, Wageningen University, Wageningen; and
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Hesketh J, Méplan C. Transcriptomics and functional genetic polymorphisms as biomarkers of micronutrient function: focus on selenium as an exemplar. Proc Nutr Soc 2011; 70:1-9. [PMID: 21557886 DOI: 10.1017/s0029665111000115] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Micronutrients are essential for optimal human health. However, in some cases, raising intake by supplementation has not proven to be beneficial and there is even some evidence that supplementation may increase disease risk, highlighting the importance of assessing the functional status of micronutrients. Techniques such as gene microarrays and single-nucleotide polymorphism analysis have the potential to examine effects of micronutrient intake on patterns of gene expression and inter-individual variation in micronutrient metabolism. Recent genomic research related to selenium (Se) provides examples illustrating how studies of functional single-nucleotide polymorphism and gene expression patterns can reveal novel biomarkers of micronutrient function. Both in vitro and in vivo experiments show that there are functionally relevant polymorphisms in genes encoding glutathione peroxidases 1, 3 and 4, selenoprotein P, selenoprotein S and the 15 kDa selenoprotein. Disease association studies investigating these gene variants have so far been relatively small but an association of a polymorphism in the selenoprotein S gene with colorectal cancer risk has been replicated in two distinct populations. Future disease association studies should examine effects of multiple variants in combination with nutritional status. Gene microarray studies indicate that changes in Se intake alter expression of components of inflammatory, stress response and translation pathways. Our hypothesis is that Se intake and genetic factors have linked effects on stress response, inflammation and apoptotic pathways. Combining such data in a systems biology approach has the potential to identify both biomarkers of micronutrients status and sub-group populations at particular risk.
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Affiliation(s)
- John Hesketh
- Institute for Cell and Molecular Biosciences and Human Nutrition Research Centre, The Medical School, Newcastle University, Framlington place, Newcastle upon Tyne NE1 4HH, UK
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59
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Ferguson LR, Karunasinghe N. Nutrigenetics, nutrigenomics, and selenium. Front Genet 2011; 2:15. [PMID: 22303312 PMCID: PMC3268570 DOI: 10.3389/fgene.2011.00015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 03/21/2011] [Indexed: 01/01/2023] Open
Abstract
Selenium (Se) is an important micronutrient that, as a component of selenoproteins, influences oxidative and inflammatory processes. Its’ levels vary considerably, with different ethnic and geographic population groups showing varied conditions, ranging from frank Se deficiencies to toxic effects. An optimum Se level is essential for the maintenance of homeostasis, and this optimum may vary according to life stage, general state of health, and genotype. Nutrigenetic studies of different Se levels, in the presence of genetic variants in selenoproteins, suggest that an effective dietary Se intake for one individual may be very different from that for others. However, we are just starting to learn the significance of various genes in selenoprotein pathways, functional variants in these, and how to combine such data from genes into pathways, alongside dietary intake or serum levels of Se. Advances in systems biology, genetics, and genomics technologies, including genetic/genomic, epigenetic/epigenomic, transcriptomic, proteomic, and metabolomic information, start to make it feasible to assess a comprehensive spectrum of the biological activity of Se. Such nutrigenomic approaches may prove very sensitive biomarkers of optimal Se status at the individual or population level. The premature cessation of a major human Se intervention trial has led to considerable controversy as to the value of Se supplementation at the population level. New websites provide convenient links to current information on methodologies available for nutrigenetics and nutrigenomics. These new technologies will increasingly become an essential tool in optimizing the level of Se and other micronutrients for optimal health, in individuals and in population groups. However, definitive proof of such effects will require very large collaborative studies, international agreement on study design, and innovative approaches to data analysis.
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Affiliation(s)
- Lynnette R Ferguson
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland Auckland, New Zealand
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60
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Brennan KM, Crowdus CA, Cantor AH, Pescatore AJ, Barger JL, Horgan K, Xiao R, Power RF, Dawson KA. Effects of organic and inorganic dietary selenium supplementation on gene expression profiles in oviduct tissue from broiler-breeder hens. Anim Reprod Sci 2011; 125:180-8. [PMID: 21511415 DOI: 10.1016/j.anireprosci.2011.02.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 02/15/2011] [Accepted: 02/28/2011] [Indexed: 01/10/2023]
Abstract
Selenium (Se) is an essential component of at least 25 selenoproteins involved in a multitude of physiological functions, including reproduction. However, relatively little is known about the mechanisms by which Se exerts its physiological effects in reproductive tissue. The objective of this study was to compare the effect of long-term inorganic Se (sodium selenite, SS) and organic yeast-derived Se (Sel-Plex(®), SP) supplementations on tissue Se content and gene expression patterns in the oviduct of broiler-breeder hens. Hens were randomly assigned at 6 weeks of age to one of the three treatments: basal semi-purified diet (control), basal diet+0.3 ppm Se as SP or basal diet+0.3 ppm Se as SS. At 49 weeks, oviduct tissue from hens randomly selected from each treatment (n=7) was analyzed for Se content and gene expression profiles using the Affymetrix Chicken genome array. Gene expression data were evaluated using GeneSpring GX 10.0 (Silicon Genetics, Redwood, CA) and Ingenuity Pathways Analysis software (Ingenuity Systems, Redwood City, CA). Oviduct Se concentration was greater with Se supplementation compared with the control (P≤0.05) but did not differ between SS- and SP-supplemented groups. Gene expression analysis revealed that the quantity of gene transcripts associated with energy production and protein translation were greater in the oviduct with SP but not SS supplementation. Targets up-regulated by SP, but not SS, included genes encoding several subunits of the mitochondrial respiratory complexes, ubiquinone production and ribosomal subunits. SS hens showed a decrease in transcripts of genes involved in respiratory complexes, ATP synthesis and protein translation and metabolism in oviduct relative to control hens. In this study, although tissue Se concentrations did not differ between hens fed SS- and SP-supplemented diets, expression patterns of genes involved in energy production and protein synthesis pathways differed between treatments. These variations may partially explain the differences in reproductive performance reported in hens fed different forms of Se.
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Affiliation(s)
- K M Brennan
- Center for Animal Nutrigenomics and Applied Animal Nutrition, Alltech Inc., Nicholasville, KY 40356, USA.
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61
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The influence of selenium-enriched milk proteins and selenium yeast on plasma selenium levels and rectal selenoprotein gene expression in human subjects. Br J Nutr 2011; 106:572-82. [PMID: 21450115 DOI: 10.1017/s0007114511000420] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Certain forms of dietary Se may have advantages for improving human Se status and regulating the risk for disease, such as cancers, including colorectal cancer (CRC). The present study compared the effects of a Se-enriched milk protein (dairy-Se) with a Se-rich yeast (yeast-Se) on plasma Se levels and rectal selenoprotein gene expression since we reasoned that if these genes were not regulated, there was little potential for regulating the risk for CRC in this organ. A total of twenty-three healthy volunteers with plasma Se in the lower half of the population range were supplemented with dairy-Se (150 μg/d) or yeast-Se (150 μg/d) for 6 weeks, followed by 6 weeks of washout period. Blood was sampled every 2 weeks, and rectal biopsies were obtained before and after Se supplementation and after the washout period. Plasma Se levels and glutathione peroxidase (GPx) activity, and rectal mRNA of selenoprotein P (SeP), cytosolic GPx-1 (GPx-1), gastrointestinal GPx-2 (GPx-2) and thioredoxin reductase-1 (TrxR-1) were measured. Plasma Se levels increased rapidly in both Se groups (P < 0·001); plasma GPx activity was not significantly changed. Rectal SeP mRNA increased at 6 weeks compared with baseline in both Se groups (P < 0·05); only dairy-Se resulted in a sustained elevation of SeP after the washout period (P < 0·05). Rectal GPx-1 and GPx-2 mRNA were higher with dairy-Se (P < 0·05) than with yeast-Se at 6 weeks. In conclusion, three rectal selenoprotein mRNA were differentially regulated by dairy-Se and yeast-Se. Changes in rectal selenoproteins are not predicted by changes in plasma Se; dairy-Se effectively regulates the expression of several rectal selenoproteins of relevance to the risk for CRC.
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62
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Goldson AJ, Fairweather-Tait SJ, Armah CN, Bao Y, Broadley MR, Dainty JR, Furniss C, Hart DJ, Teucher B, Hurst R. Effects of selenium supplementation on selenoprotein gene expression and response to influenza vaccine challenge: a randomised controlled trial. PLoS One 2011; 6:e14771. [PMID: 21445287 PMCID: PMC3061857 DOI: 10.1371/journal.pone.0014771] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 02/08/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The uncertainty surrounding dietary requirements for selenium (Se) is partly due to limitations in biomarkers of Se status that are related to health outcomes. In this study we determined the effect of different doses and forms of Se on gene expression of selenoprotein S (SEPS1), selenoprotein W (SEPW1) and selenoprotein R (SEPR), and responses to an immune function challenge, influenza vaccine, were measured in order to identify functional markers of Se status. METHODS AND FINDINGS A 12 week human dietary intervention study was undertaken in 119 volunteers who received placebo, 50, 100 or 200 µg/day Se-enriched yeast (Se-yeast) or meals containing unenriched or Se-enriched onions (50 µg/day). Gene expression was quantified in RNA samples extracted from human peripheral blood mononuclear cells (PBMC's) using quantitative RT-PCR. There was a significant increase in SEPW1 mRNA in the Se-enriched onion group (50 µg/day) compared with the unenriched onion group. SEPR and SEPW1 did not change significantly over the duration of the supplementation period in the control or Se-yeast groups, except at week 10 when SEPW1 mRNA levels were significantly lower in the 200 µg/day Se-yeast group compared to the placebo group. Levels of SEPS1 mRNA increased significantly 7 days after the influenza vaccine challenge, the magnitude of the increase in SEPS1 gene expression was dose-dependent, with a significantly greater response with higher Se supplementation. CONCLUSIONS This novel finding provides preliminary evidence for a role of SEPS1 in the immune response, and further supports the relationship between Se status and immune function. TRIAL REGISTRATION ClinicalTrials.gov [NCT00279812].
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Affiliation(s)
- Andrew J. Goldson
- Institute of Food Research, Norwich Research Park, Norwich, United
Kingdom
| | | | - Charlotte N. Armah
- Institute of Food Research, Norwich Research Park, Norwich, United
Kingdom
| | - Yongping Bao
- Norwich Medical School, University of East Anglia, Norwich, United
Kingdom
| | - Martin R. Broadley
- School of Biosciences, University of Nottingham, Sutton Bonington,
Loughborough, United Kingdom
| | - Jack R. Dainty
- Institute of Food Research, Norwich Research Park, Norwich, United
Kingdom
| | - Caroline Furniss
- Institute of Food Research, Norwich Research Park, Norwich, United
Kingdom
| | - David J. Hart
- Institute of Food Research, Norwich Research Park, Norwich, United
Kingdom
| | - Birgit Teucher
- Institute of Food Research, Norwich Research Park, Norwich, United
Kingdom
| | - Rachel Hurst
- Norwich Medical School, University of East Anglia, Norwich, United
Kingdom
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63
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Sunde RA, Raines AM. Selenium regulation of the selenoprotein and nonselenoprotein transcriptomes in rodents. Adv Nutr 2011; 2:138-50. [PMID: 22332043 PMCID: PMC3065762 DOI: 10.3945/an.110.000240] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This review discusses progress in understanding the hierarchy of selenoprotein expression at the transcriptome level from selenium (Se) deficiency to Se toxicity. Microarray studies of the full selenoproteome have found that 5 of 24 rodent selenoprotein mRNA decrease to <40% of Se adequate levels in Se deficient liver but that the majority of selenoprotein mRNA are not regulated by Se deficiency. These differences match with the hierarchy of selenoprotein expression, helping to explain these differences and also showing that selenoprotein transcripts can be used as molecular biomarkers for assessing Se status. The similarity of the response curves for regulated selenoproteins suggests one underlying mechanism is responsible for the downregulation of selenoprotein mRNA in Se deficiency, but the heterogeneity of the UGA position in regulated and nonregulated selenoprotein transcripts now indicates that current nonsense mediated decay models cannot explain which transcripts are susceptible to mRNA decay. Microarray studies on the full liver transcriptome in rats found only <10 transcripts/treatment were significantly down- or upregulated by Se deficiency or by supernutritional Se up to 2.0 μg Se/g diet (20× requirement), suggesting that cancer prevention associated with supernutritional Se may not be mediated by transcriptional changes. Toxic dietary Se at 50× requirement (5 μg Se/g diet), however, significantly altered ∼4% of the transcriptome, suggesting number of transcriptional changes itself as a biomarker of Se toxicity. Finally, panels of Se regulated selenoprotein plus nonselenoprotein transcripts predict Se status from deficient to toxic better than conventional biomarkers, illustrating potential roles for molecular biomarkers in nutrition.
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Raines AM, Sunde RA. Selenium toxicity but not deficient or super-nutritional selenium status vastly alters the transcriptome in rodents. BMC Genomics 2011; 12:26. [PMID: 21226930 PMCID: PMC3032699 DOI: 10.1186/1471-2164-12-26] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 01/12/2011] [Indexed: 11/16/2022] Open
Abstract
Background Protein and mRNA levels for several selenoproteins, such as glutathione peroxidase-1 (Gpx1), are down-regulated dramatically by selenium (Se) deficiency. These levels in rats increase sigmoidally with increasing dietary Se and reach defined plateaus at the Se requirement, making them sensitive biomarkers for Se deficiency. These levels, however, do not further increase with super-nutritional or toxic Se status, making them ineffective for detection of high Se status. Biomarkers for high Se status are needed as super-nutritional Se intakes are associated with beneficial as well as adverse health outcomes. To characterize Se regulation of the transcriptome, we conducted 3 microarray experiments in weanling mice and rats fed Se-deficient diets supplemented with up to 5 μg Se/g diet. Results There was no effect of Se status on growth of mice fed 0 to 0.2 μg Se/g diet or rats fed 0 to 2 μg Se/g diet, but rats fed 5 μg Se/g diet showed a 23% decrease in growth and elevated plasma alanine aminotransferase activity, indicating Se toxicity. Rats fed 5 μg Se/g diet had significantly altered expression of 1193 liver transcripts, whereas mice or rats fed ≤ 2 μg Se/g diet had < 10 transcripts significantly altered relative to Se-adequate animals within an experiment. Functional analysis of genes altered by Se toxicity showed enrichment in cell movement/morphogenesis, extracellular matrix, and development/angiogenesis processes. Genes up-regulated by Se deficiency were targets of the stress response transcription factor, Nrf2. Multiple regression analysis of transcripts significantly altered by 2 μg Se/g and Se-deficient diets identified an 11-transcript biomarker panel that accounted for 99% of the variation in liver Se concentration over the full range from 0 to 5 μg Se/g diet. Conclusion This study shows that Se toxicity (5 μg Se/g diet) in rats vastly alters the liver transcriptome whereas Se-deficiency or high but non-toxic Se intake elicits relatively few changes. This is the first evidence that a vastly expanded number of transcriptional changes itself can be a biomarker of Se toxicity, and that identified transcripts can be used to develop molecular biomarker panels that accurately predict super-nutritional and toxic Se status.
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Affiliation(s)
- Anna M Raines
- Department of Nutritional Sciences, University of Wisconsin, 1415 Linden Drive, Madison, WI 53706, USA
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Méplan C. Trace elements and ageing, a genomic perspective using selenium as an example. J Trace Elem Med Biol 2011; 25 Suppl 1:S11-6. [PMID: 21145717 DOI: 10.1016/j.jtemb.2010.10.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 10/26/2010] [Indexed: 01/09/2023]
Abstract
Trace elements are key regulators of metabolic and physiological pathways known to be altered during the ageing process and therefore have the capacity to modulate the rate of biological ageing. Optimal intake is required to maintain homeostasis and to increase cell protection. Deficiencies are associated with specific illnesses. However the contribution of commonly observed life-long sub-optimal intakes of trace elements to the development and severity of age-related chronic diseases is less appreciated. Additionally, reduce intake of several trace elements has been shown to be particularly challenging for elderly people. This review will use selenium as an example to illustrate how a trace element can influence ageing and how the Omics technologies could help to study the effect of trace elements on the ageing process. Although transcriptomics and proteomics approaches in animal models have so far enabled us to identify downstream targets of trace elements in pathways related to age-related diseases processes, future approaches of combining nutrigenomics with longevity studies in humans will help us to identify mechanisms whereby trace elements affect the ageing process.
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Affiliation(s)
- Catherine Méplan
- Institute for Cell and Molecular Biosciences and Human Nutrition Research Centre, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne NE24HH, UK.
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66
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McHale CM, Zhang L, Hubbard AE, Smith MT. Toxicogenomic profiling of chemically exposed humans in risk assessment. Mutat Res 2010; 705:172-83. [PMID: 20382258 PMCID: PMC2928857 DOI: 10.1016/j.mrrev.2010.04.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 04/01/2010] [Indexed: 12/13/2022]
Abstract
Gene-environment interactions contribute to complex disease development. The environmental contribution, in particular low-level and prevalent environmental exposures, may constitute much of the risk and contribute substantially to disease. Systematic risk evaluation of the majority of human chemical exposures, has not been conducted and is a goal of regulatory agencies in the U.S. and worldwide. With the recent recognition that toxicological approaches more predictive of effects in humans are required for risk assessment, in vitro human cell line data as well as animal data are being used to identify toxicity mechanisms that can be translated into biomarkers relevant to human exposure studies. In this review, we discuss how data from toxicogenomic studies of exposed human populations can inform risk assessment, by generating biomarkers of exposure, early effect, and/or susceptibility, elucidating mechanisms of action underlying exposure-related disease, and detecting response at low doses. Good experimental design incorporating precise, individual exposure measurements, phenotypic anchors (pre-disease or traditional toxicological markers), and a range of relevant exposure levels, is necessary. Further, toxicogenomic studies need to be designed with sufficient power to detect true effects of the exposure. As more studies are performed and incorporated into databases such as the Comparative Toxicogenomics Database (CTD) and Chemical Effects in Biological Systems (CEBS), data can be mined for classification of newly tested chemicals (hazard identification), and, for investigating the dose-response, and inter-relationship among genes, environment and disease in a systems biology approach (risk characterization).
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Affiliation(s)
- Cliona M. McHale
- School of Public Health, Division of Environmental Health Sciences, University of California, Berkeley, CA 94720
| | - Luoping Zhang
- School of Public Health, Division of Environmental Health Sciences, University of California, Berkeley, CA 94720
| | - Alan E. Hubbard
- School of Public Health, Division of Biostatistics, University of California, Berkeley, CA 94720
| | - Martyn T. Smith
- School of Public Health, Division of Environmental Health Sciences, University of California, Berkeley, CA 94720
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67
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van Ommen B, El-Sohemy A, Hesketh J, Kaput J, Fenech M, Evelo CT, McArdle HJ, Bouwman J, Lietz G, Mathers JC, Fairweather-Tait S, van Kranen H, Elliott R, Wopereis S, Ferguson LR, Méplan C, Perozzi G, Allen L, Rivero D. The Micronutrient Genomics Project: a community-driven knowledge base for micronutrient research. GENES AND NUTRITION 2010; 5:285-96. [PMID: 21189865 PMCID: PMC2989004 DOI: 10.1007/s12263-010-0192-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Accepted: 10/13/2010] [Indexed: 01/19/2023]
Abstract
Micronutrients influence multiple metabolic pathways including oxidative and inflammatory processes. Optimum micronutrient supply is important for the maintenance of homeostasis in metabolism and, ultimately, for maintaining good health. With advances in systems biology and genomics technologies, it is becoming feasible to assess the activity of single and multiple micronutrients in their complete biological context. Existing research collects fragments of information, which are not stored systematically and are thus not optimally disseminated. The Micronutrient Genomics Project (MGP) was established as a community-driven project to facilitate the development of systematic capture, storage, management, analyses, and dissemination of data and knowledge generated by biological studies focused on micronutrient–genome interactions. Specifically, the MGP creates a public portal and open-source bioinformatics toolbox for all “omics” information and evaluation of micronutrient and health studies. The core of the project focuses on access to, and visualization of, genetic/genomic, transcriptomic, proteomic and metabolomic information related to micronutrients. For each micronutrient, an expert group is or will be established combining the various relevant areas (including genetics, nutrition, biochemistry, and epidemiology). Each expert group will (1) collect all available knowledge, (2) collaborate with bioinformatics teams towards constructing the pathways and biological networks, and (3) publish their findings on a regular basis. The project is coordinated in a transparent manner, regular meetings are organized and dissemination is arranged through tools, a toolbox web portal, a communications website and dedicated publications.
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Affiliation(s)
- Ben van Ommen
- TNO Quality of Life, P.O. box 360, 3700 AJ Zeist, The Netherlands
| | - Ahmed El-Sohemy
- Department of Nutritional Sciences, University of Toronto, 150 College Street, Toronto, ON M5S 3E2 Canada
| | - John Hesketh
- Institute for Cell and Molecular Biosciences, Newcastle University Medical School and Human Nutrition Research Centre, Newcastle-upon-Tyne, NE2 4HH UK
| | - Jim Kaput
- Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079 USA
| | - Michael Fenech
- CSIRO Food and Nutritional Sciences, PO Box 10041, Adelaide BC, SA 5000 Australia
| | - Chris T. Evelo
- Department of Bioinformatics—BiGCaT, Maastricht University, Maastricht, The Netherlands
| | - Harry J. McArdle
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, AB21 9SB UK
| | - Jildau Bouwman
- TNO Quality of Life, P.O. box 360, 3700 AJ Zeist, The Netherlands
| | - Georg Lietz
- Human Nutrition Research Centre, School of Agriculture, Food and Rural Development, Newcastle University, Kings Road, Agriculture Building, Newcastle upon Tyne, NE1 7RU UK
| | - John C. Mathers
- Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, NE2 4HH UK
| | - Sue Fairweather-Tait
- School of Medicine, Health Policy and Practice, University of East Anglia, Norwich, NR4 7TJ UK
| | | | - Ruan Elliott
- Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA UK
| | - Suzan Wopereis
- TNO Quality of Life, P.O. box 360, 3700 AJ Zeist, The Netherlands
| | - Lynnette R. Ferguson
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Catherine Méplan
- Institute for Cell and Molecular Biosciences, Newcastle University Medical School and Human Nutrition Research Centre, Newcastle-upon-Tyne, NE2 4HH UK
| | - Giuditta Perozzi
- Department of Nutritional Sciences—INRAN, National Research Institute on Food & Nutrition, Via Ardeatina 546, 00178 Rome, Italy
| | - Lindsay Allen
- USDA, ARS Western Human Nutrition Research Center, University of California, 530 W. Health Sciences Drive, Davis, CA 95616 USA
| | - Damariz Rivero
- Department of Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy
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68
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Sunde RA. Molecular biomarker panels for assessment of selenium status in rats. Exp Biol Med (Maywood) 2010; 235:1046-52. [PMID: 20724535 DOI: 10.1258/ebm.2010.010111] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Molecular biomarkers are mRNA transcripts that indicate the (nutrient) status of an organism or tissue. Molecular biomarker panels have the potential to readily and more accurately determine nutrient status than individual traditional biomarkers. To study the efficacy of molecular biomarker panels for predicting selenium (Se) status, we examined 30 biomarkers from rats fed graded levels of Se from deficient to eight times the minimum Se requirement, including four liver and four kidney traditional biomarkers, and 13 liver and nine kidney selenoprotein mRNA levels. Multiple regression analysis against liver and kidney Se and glutathione peroxidase-1 (Gpx1) activity, with stepwise single elimination of biomarkers that did not significantly contribute, was used to identify biomarker panels with significant (P < 0.05) regression coefficients. Resulting regression equations were then used to predict Se status, and compared with traditional Se biomarkers panels. Over the full spectrum of Se status from 0 to 0.8 microg Se/g diet, the resulting 4-selenoprotein mRNA biomarker panel predicted liver Se concentration with a correlation of 0.948, which was nominally higher and statistically the same as the correlation of 0.909 for the panel based on Gpx1 activity. The molecular biomarker panels for predicting kidney Se and liver and kidney Gpx1 activity were all comparable to predictions based on traditional biomarkers. These analyses show that molecular biomarker panels can be used to predict accurately two traditional biomarkers of Se status. The resulting analyses also illustrate that additional orthogonal biomarkers reflecting higher Se intakes are needed to better predict supernutritional Se status and further strengthen this approach.
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Affiliation(s)
- Roger A Sunde
- Department of Nutritional Sciences, University of Wisconsin, 1415 Linden Drive, Madison, WI 53706, USA.
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69
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Quercetin supplementation and its effect on human monocyte gene expression profiles in vivo. Br J Nutr 2010; 104:336-45. [DOI: 10.1017/s0007114510000711] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Quercetin has been described as having a wide range of beneficial effects in humans, ranging from anti-carcinogenic properties to reducing the risk of CVD. Nevertheless, underlying molecular mechanisms have been mostly investigated in vitro. Here, we tested whether a daily supplementation of quercetin leads to reproducible changes in human monocyte gene expression profiles. In study I, quercetin in varying dosages was given to healthy subjects for 2 weeks. RNA from monocytes isolated at the beginning and end of the study from subjects receiving 150 mg quercetin per d was subjected to transcriptome-wide microarray analysis. In study II, a double-blind cross-over study, twenty subjects exhibiting a ‘cardiovascular risk phenotype’ received 150 mg quercetin or placebo daily for 6 weeks each and served as the verification group. Microarray analysis revealed a number of differentially expressed genes. The most significantly represented functional groups were those of the immune system, nucleic acid metabolism, apoptosis and O-glycan biosynthesis. Twenty-four genes were chosen for technical replication and independent verification by quantitative real-time PCR. When comparing placebo and quercetin treatment, four genes showed significantly different expression changes (C1GALT1, O-glycan biosynthesis; GM2A, glycolipid catabolism; HDGF, cell proliferation; SERPINB9, apoptosis). However, these were minimal in respect to magnitude of fold change. In conclusion, although microarray analysis revealed extensive effects of quercetin on gene expression, the employment of a placebo-controlled study design showed no comparable results for twenty-four verification targets. This emphasises the need for stringent designs in nutritional intervention studies with the aim to identify relevant changes in gene expression.
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70
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Selenius M, Rundlöf AK, Olm E, Fernandes AP, Björnstedt M. Selenium and the selenoprotein thioredoxin reductase in the prevention, treatment and diagnostics of cancer. Antioxid Redox Signal 2010; 12:867-80. [PMID: 19769465 DOI: 10.1089/ars.2009.2884] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Selenium is an essential element that is specifically incorporated as selenocystein into selenoproteins. It is a potent modulator of eukaryotic cell growth with strictly concentration-dependant effects. Lower concentrations are necessary for cell survival and growth, whereas higher concentrations inhibit growth and induce cell death. It is well established that selenium has cancer preventive effects, and several studies also have shown that it has strong anticancer effects with a selective cytotoxicity on malignant drug-resistant cells while only exerting marginal effects on normal and benign cells. This cancer-specific cytotoxicity is likely explained by high affinity selenium uptake dependent on proteins connected to multidrug resistance. One of the most studied selenoproteins in cancer is thioredoxin reductase (TrxR) that has important functions in neoplastic growth and is an important component of the resistant phenotype. Several reports have shown that TrxR is induced in tumor cells and pre-neoplastic cells, and several commonly used drugs interact with the protein. In this review, we summarize the current knowledge of selenium as a potent preventive and tumor selective anticancer drug, and we also discuss the potential of using the expression and modulation of the selenoprotein TrxR in the diagnostics and treatment of cancer.
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Affiliation(s)
- Markus Selenius
- Division of Pathology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
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71
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Selenium-enriched milk proteins and selenium yeast affect selenoprotein activity and expression differently in mouse colon. Br J Nutr 2010; 104:17-23. [PMID: 20346189 DOI: 10.1017/s0007114510000309] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Certain forms of dietary Se may have an advantage in improving Se status and reducing cancer risk. The present study compared the effects of an Se-enriched milk protein product (dairy-Se) with an Se yeast (yeast-Se) on selenoprotein activity and expression in the mouse colon. Mice were fed four diets for 4 weeks: a control milk protein diet (Se at 0.068 parts per million (ppm)), dairy-Se diets with Se at 0.5 and 1 ppm, and a yeast-Se diet with Se at 1 ppm. Cytosolic glutathione peroxidase-1 (GPx-1) activity, mRNA of selenoprotein P (SeP), GPx-1, gastrointestinal glutathione peroxidase-2 (GPx-2) and thioredoxin reductase-1 (TrxR-1) were examined in the mouse colon. Dairy-Se diets did not significantly affect GPx-1 mRNA and GPx-1 activity but produced a dose-dependent increase in SeP and GPx-2 mRNA, with a significantly higher level achieved at 1 ppm Se (P < 0.05). Yeast-Se at 1 ppm significantly increased GPx-1 mRNA and GPx-1 activity (P < 0.01) but not GPx-2 mRNA. Neither Se supplement had any effect on TrxR-1. The present study indicates that selenoprotein levels in the mouse colon are regulated differently depending on the Se supplement. As we have previously shown that dairy-Se at 1 ppm was protective against colorectal cancer (CRC) in an azoxymethane-induced CRC mouse model, this up-regulation of colonic GPx-2 and SeP with Se supplementation may be crucial to its chemopreventive action.
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72
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Kipp A, Banning A, van Schothorst EM, Méplan C, Schomburg L, Evelo C, Coort S, Gaj S, Keijer J, Hesketh J, Brigelius-Flohé R. Four selenoproteins, protein biosynthesis, and Wnt signalling are particularly sensitive to limited selenium intake in mouse colon. Mol Nutr Food Res 2010; 53:1561-72. [PMID: 19810021 DOI: 10.1002/mnfr.200900105] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Selenium is an essential micronutrient. Its recommended daily allowance is not attained by a significant proportion of the population in many countries and its intake has been suggested to affect colorectal carcinogenesis. Therefore, microarrays were used to determine how both selenoprotein and global gene expression patterns in the mouse colon were affected by marginal selenium deficiency comparable to variations in human dietary intakes. Two groups of 12 mice each were fed a selenium-deficient (0.086 mg Se/kg) or a selenium-adequate (0.15 mg Se/kg) diet. After 6 wk, plasma selenium level, liver, and colon glutathione peroxidase (GPx) activity in the deficient group was 12, 34, and 50%, respectively, of that of the adequate group. Differential gene expression was analysed with mouse 44K whole genome microarrays. Pathway analysis by GenMAPP identified the protein biosynthesis pathway as most significantly affected, followed by inflammation, Delta-Notch and Wnt pathways. Selected gene expression changes were confirmed by quantitative real-time PCR. GPx1 and the selenoproteins W, H, and M, responded significantly to selenium intake making them candidates as biomarkers for selenium status. Thus, feeding a marginal selenium-deficient diet resulted in distinct changes in global gene expression in the mouse colon. Modulation of cancer-related pathways may contribute to the higher susceptibility to colon carcinogenesis in low selenium status.
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Affiliation(s)
- Anna Kipp
- German Institute of Human Nutrition Potsdam-Rehbruecke, Germany
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73
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Keijer J, van Helden YGJ, Bunschoten A, van Schothorst EM. Transcriptome analysis in benefit-risk assessment of micronutrients and bioactive food components. Mol Nutr Food Res 2010; 54:240-8. [DOI: 10.1002/mnfr.200900304] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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74
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Selenium depletion modulates the expression of the protein biosynthetic pathway in Caco-2 cells. Proc Nutr Soc 2010. [DOI: 10.1017/s0029665110002582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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75
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Kandaş NO, Randolph C, Bosland MC. Differential effects of selenium on benign and malignant prostate epithelial cells: stimulation of LNCaP cell growth by noncytotoxic, low selenite concentrations. Nutr Cancer 2009; 61:251-64. [PMID: 19235042 DOI: 10.1080/01635580802398430] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
We examined the hypothesis that nontoxic concentrations of selenium induce apoptosis and growth inhibition selectively in prostate cancer cells but not in benign prostate cells. Nontumorigenic BPH-1 prostate epithelial cells, androgen-sensitive LNCaP, and androgen-independent PC-3 prostate cancer cells were exposed to sodium selenite at 1 to 10 micromol/l for 24 to 72 h. Cell proliferation, viability, and apoptosis were assessed by MTT assay, trypan blue exclusion, flow cytometry, DNA laddering, and caspase activation. BPH-1 cells were more sensitive for cytotoxic selenium effects than malignant prostate cells, whereas LNCaP cells were more sensitive than PC-3 cells. At noncytotoxic selenium concentrations, there was no apoptosis in BPH-1 and PC-3 cells and no growth inhibition of LNCaP and BPH-1 cells. PC-3 cells were refractory to apoptosis induction but were growth inhibited at noncytotoxic concentrations. LNCaP cells were growth stimulated at 1 micromol/l and sensitive to apoptosis induction at higher noncytotoxic concentrations. Thus, noncytotoxic selenite concentrations did not induce growth inhibition or apoptosis selectively in prostate cancer cells. Growth stimulation of LNCaP cells by low concentrations suggests the possibility of adverse effects of selenium supplementation on hormone sensitive prostate cancer, whereas inhibition of PC-3 cell proliferation at noncytotoxic concentrations suggests potential benefit of selenium in advanced prostate cancer.
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Affiliation(s)
- Nur Ozten Kandaş
- Department of Pathology, University of Illinois at Chicago, 840 South Wood Street, Chicago, IL 60612, USA
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76
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Ashton K, Hooper L, Harvey LJ, Hurst R, Casgrain A, Fairweather-Tait SJ. Methods of assessment of selenium status in humans: a systematic review. Am J Clin Nutr 2009; 89:2025S-2039S. [PMID: 19420095 DOI: 10.3945/ajcn.2009.27230f] [Citation(s) in RCA: 205] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND To understand the effect of selenium intake on health, it is important to identify sensitive and population-specific biomarkers of selenium status. OBJECTIVE The objective of this systematic review was to assess the usefulness of biomarkers of selenium status in humans. DESIGN The methods included a structured search strategy on Ovid MEDLINE, EMBASE (Ovid), and Cochrane databases; formal inclusion and exclusion criteria; data extraction into an Access database; validity assessment; and meta-analysis. RESULTS The data from 18 selenium supplementation studies (of which 9 were randomized controlled trials and 1 was considered to be at low risk of bias) indicate that plasma, erythrocyte, and whole-blood selenium, plasma selenoprotein P, and plasma, platelet, and whole-blood glutathione peroxidase activity respond to changes in selenium intake. Although there is a substantial body of data for plasma selenium, more large, high-quality, randomized controlled trials are needed for this biomarker, as well as for the other biomarkers, to explore the reasons for heterogeneity in response to selenium supplementation. There was insufficient evidence to assess the usefulness of other potential biomarkers of selenium status, including urinary selenium, plasma triiodothyroxine:thyroxine ratio, plasma thyroxine, plasma total homocysteine, hair and toenail selenium, erythrocyte, and muscle glutathione peroxidase activity. CONCLUSIONS For all potentially useful biomarkers, more information is needed to evaluate their strengths and limitations in different population groups, including the effects of varying intakes, the duration of intervention, baseline selenium status, and possible confounding effects of genotype.
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Affiliation(s)
- Kate Ashton
- School of Medicine, Health Policy and Practice, the University of East Anglia, Norwich, United Kingdom
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77
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van Schothorst EM, Flachs P, Franssen-van Hal NLW, Kuda O, Bunschoten A, Molthoff J, Vink C, Hooiveld GJEJ, Kopecky J, Keijer J. Induction of lipid oxidation by polyunsaturated fatty acids of marine origin in small intestine of mice fed a high-fat diet. BMC Genomics 2009; 10:110. [PMID: 19284886 PMCID: PMC2662879 DOI: 10.1186/1471-2164-10-110] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Accepted: 03/16/2009] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Dietary polyunsaturated fatty acids (PUFA), in particular the long chain marine fatty acids docosahexaenoic (DHA) and eicosapentaenoic (EPA), are linked to many health benefits in humans and in animal models. Little is known of the molecular response to DHA and EPA of the small intestine, and the potential contribution of this organ to the beneficial effects of these fatty acids. Here, we assessed gene expression changes induced by DHA and EPA in the wildtype C57BL/6J murine small intestine using whole genome microarrays and functionally characterized the most prominent biological process. RESULTS The main biological process affected based on gene expression analysis was lipid metabolism. Fatty acid uptake, peroxisomal and mitochondrial beta-oxidation, and omega-oxidation of fatty acids were all increased. Quantitative real time PCR, and -- in a second animal experiment -- intestinal fatty acid oxidation measurements confirmed significant gene expression differences and showed in a dose-dependent manner significant changes at biological functional level. Furthermore, no major changes in the expression of lipid metabolism genes were observed in the colon. CONCLUSION We show that marine n-3 fatty acids regulate small intestinal gene expression and increase fatty acid oxidation. Since this organ contributes significantly to whole organism energy use, this effect on the small intestine may well contribute to the beneficial physiological effects of marine PUFAs under conditions that will normally lead to development of obesity, insulin resistance and diabetes.
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Affiliation(s)
- Evert M van Schothorst
- Food Bioactives Group, RIKILT Institute of Food Safety, Wageningen UR, Wageningen, The Netherlands.
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78
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Hawkes WC, Hwang A, Alkan Z. The effect of selenium supplementation on DTH skin responses in healthy North American men. J Trace Elem Med Biol 2009; 23:272-80. [PMID: 19747623 DOI: 10.1016/j.jtemb.2009.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 03/27/2009] [Accepted: 04/29/2009] [Indexed: 01/01/2023]
Abstract
The trace element selenium (Se) is essential for immune system development and function in animals. However, the exact functions of Se in the human immune system and the achievable health benefits from Se supplementation remain unclear. To test whether an increased intake of dietary Se affects immune function, we conducted a randomized, controlled trial of Se supplementation in healthy free-living men. Forty-two men were administered 300microg of Se a day as high-Se Baker's yeast, or low-Se yeast for 48 weeks. Serum immunoglobulins, differential complete blood counts and lymphocyte sub-populations were measured every 6 weeks. Tests of delayed-type hypersensitivity (DTH) skin responses to mumps, candida, trychophyton, tuberculin-purified protein, and tetanus were performed at baseline and at the end of 48 weeks of treatment. Supplementation increased blood Se concentration by 50%. Surprisingly, consumption of the low-Se yeast induced anergy in DTH skin responses and increased counts of natural killer (NK) cells and T lymphocytes expressing both subunits of the high affinity interleukin-2 receptor (IL2R). DTH skin responses and IL2R+ cells did not change in the high-Se group, suggesting Se supplementation blocked induction of DTH anergy. There were no differences between groups in quality of life indicators, number of days sick, other leukocyte phenotypes, serum immunoglobulins, or complement factors. These results suggest that Se plays a role in immunotolerization, a cell-mediated process involved in many aspects of immune function.
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Affiliation(s)
- Wayne Chris Hawkes
- United States Department of Agriculture, Agricultural Research Service, Western Human Nutrition Research Center, University of California at Davis, 430 West Health Sciences Drive, Davis, CA 95616, USA.
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79
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Abstract
PURPOSE OF REVIEW To discuss recent research related to anticarcinogenic mechanisms of selenium action in light of the underlying chemical/biochemical functions of the selenium species, likely to be executors of those effects. RECENT FINDINGS Recent studies in a variety of model systems have increased the understanding of the anticarcinogenic mechanisms of selenium compounds. These include effects on gene expression, DNA damage and repair, signaling pathways, regulation of cell cycle and apoptosis, metastasis and angiogenesis. These effects would appear to be related to the production of reactive oxygen species produced by the redox cycling, modification of protein-thiols and methionine mimicry. Three principle selenium metabolites appear to execute these effects: hydrogen selenide, methylselenol and selenomethionine. The fact that various selenium compounds can be metabolized to one or more of these species but differ in anticarcinogenic activity indicates competing pathways of their metabolic and chemical/biochemical disposition. Increasing knowledge of selenoprotein polymorphisms has shown that at least some are related to cancer risk and may affect carcinogenesis indirectly by influencing selenium metabolism. SUMMARY The anticarcinogenic effects of selenium compounds constitute intermediate mechanisms with several underlying chemical/biochemical mechanisms such as redox cycling, alteration of protein-thiol redox status and methionine mimicry.
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Affiliation(s)
- Matthew I Jackson
- Grand Forks Human Nutrition Research Center, USDA-ARS, Grand Forks, North Dakota 58202-9034, USA
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80
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Abstract
This review examines the extent to which transcriptomic methods have lived up to their promise in the context of nutrition research, placing particular emphasis on examples from micronutrient research. A case is made that the high quality platform technologies now available, together with established standards and systems for data storage and exchange and powerful new methods of data analysis, mean that microarrays have reached a level of technical maturity at which they can be exploited to their full potential. In the context of nutrition and micronutrient research, transcriptomic methods have already been widely applied, albeit primarily in studies using cell lines and animal models. Using this type of approach, a multitude of genes regulated at the mRNA level by dietary components has been identified and this, in turn, has provided new insights into the biological processes affected by nutritional parameters. Evidence from the very limited number of published transcriptomics-based nutritional studies performed in human volunteers suggests that, with appropriate study design, it is feasible to apply transcriptomic methods successfully in dietary intervention trials. On the other hand, gene expression-based biomarker development still poses a major challenge. Here the use of expression profile 'signatures', rather than single genes, may provide a solution. Approaches designed to identify such 'signatures' are being developed and tested widely, primarily in the context of medical research. The applicability and power of such approaches should also be evaluated in the context of nutrition.
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81
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Hesketh J. Nutrigenomics and Selenium: Gene Expression Patterns, Physiological Targets, and Genetics. Annu Rev Nutr 2008; 28:157-77. [DOI: 10.1146/annurev.nutr.28.061807.155446] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- John Hesketh
- Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle-upon-Tyne, United Kingdom, NE1 4HH;
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van Ommen B, Keijer J, Kleemann R, Elliott R, Drevon CA, McArdle H, Gibney M, Müller M. The challenges for molecular nutrition research 2: quantification of the nutritional phenotype. GENES AND NUTRITION 2008; 3:51-9. [PMID: 18850187 DOI: 10.1007/s12263-008-0084-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Accepted: 05/26/2008] [Indexed: 12/20/2022]
Abstract
In quantifying the beneficial effect of dietary interventions in healthy subjects, nutrition research meets a number of new challenges. Inter individual variation in biomarker values often is larger than the effect related to the intervention. Healthy subjects have a remarkable capacity to maintain homeostasis, both through direct metabolic regulation, metabolic compensation of altered diets, and effective defence and repair mechanisms in oxidative and inflammatory stress. Processes involved in these regulatory activities essentially different from processes involved in early onset of diet related diseases. So, new concepts and approaches are needed to better quantify the subtle effects possibly achieved by dietary interventions in healthy subjects. Apart from quantification of the genotype and food intake (these are discussed in separate reviews in this series), four major areas of innovation are discussed: the biomarker profile concept, perturbation of homeostasis combined with omics analysis, imaging, modelling and fluxes. All of these areas contribute to a better understanding and quantification of the nutritional phenotype.
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Affiliation(s)
- Ben van Ommen
- Department of BioSciences, TNO-Quality of Life, Zeist, The Netherlands,
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Longitudinal selenium status in healthy British adults: assessment using biochemical and molecular biomarkers. Br J Nutr 2008; 99 Suppl 3:S37-47. [PMID: 18598587 PMCID: PMC3137460 DOI: 10.1017/s0007114508006831] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Human selenium (Se) requirements are currently based on biochemical markers of Se status. In rats, tissue glutathione peroxidase-1 (Gpx1) mRNA levels can be used effectively to determine Se requirements; blood Gpx1 mRNA levels decrease in Se-deficient rats, so molecular biology-based markers have potential for human nutrition assessment. To study the efficacy of molecular biology markers for assessing Se status in humans, we conducted a longitudinal study on 39 subjects (age 45 +/- 11) in Reading, UK. Diet diaries (5 day) and blood were obtained from each subject at 2, 8, 17 and 23 weeks, and plasma Se, glutathione peroxidase (Gpx3) enzyme activity, and selenoprotein mRNA levels were determined. There were no significant longitudinal effects on Se biomarkers. Se intake averaged 48 +/- 14 microg/d. Plasma Se concentrations averaged 1.13 +/- 0.16 micromol/l. Plasma Se v. energy-corrected Se intake (ng Se/kJ/d) was significantly correlated, but neither Gpx3 activity v. Se intake (ng Se/kJ/d) nor Gpx3 activity v. plasma Se was significantly correlated. Collectively, this indicates that subjects were on the plateaus of the response curves. Selenoprotein mRNAs were quantitated in total RNA isolated from whole blood, but mRNA levels for Gpx1, selenoprotein H, and selenoprotein W (all highly regulated by Se in rodents), as well selenoprotein P, Gpx3, and phospholipid hydroperoxide glutathione peroxidase were also not significantly correlated with plasma Se. Thus selenoprotein molecular biomarkers, as well as traditional biochemical markers, are unable to further distinguish differences in Se status in these Se replete subjects. The efficacy of molecular biomarkers to detect Se deficiency needs to be tested in Se-deficient populations.
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