Insights into the Chemical Biology of Selenium

Glass, Richard S.; Berry, Marla J.; Block, Eric; Boakye, Harriet Totoe; Carlson, Bradley A.; Gailer, Jürgen; George, Graham N.; Gladyshev, Vadim N.; Hatfield, Dolph L.; Jacobsen, Neil E.; Johnson, Sherida; Kahakachchi, Chethaka; Kamiński, Rafał M.; Manley, Shawn A.; Mix, Heiko; Pickering, Ingrid J.; Prenner, Elmar J.; Saira, Kazima; Skowronska, A.; Tyson, Julian F.; Uden, Peter C.; Wu, Qian; Xu, Xueming; Yamdagni, Raghav; Zhang, Yan

doi:10.1080/10426500801898366

Cited by 7 publications

(4 citation statements)

References 19 publications

(15 reference statements)

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“…93 The selenium required for the synthesis of selenocysteyl-tRNA [Ser]Sec from phosphoseryl-tRNA [Ser]Sec is provided by monoselenophosphate (H 2 SePO 3 À ), which can be synthesised in vitro from the reaction of HSe À and ATP catalysed by selenophosphate synthetase; providing further evidence for HSe À as the common selenium intermediate. [94][95][96] Two distinct pathways are available for excretion of selenium: the methylation pathway and the selenosugar pathway. The biological significance of selenosugars is unknown, 97 but methylation is considered a detoxification pathway due to the low toxicity of the methylated metabolites.…”

Section: Downstream Metabolitesmentioning

confidence: 99%

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Which form is that? The importance of selenium speciation and metabolism in the prevention and treatment of disease

2013

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The biological activity of selenium is dependent upon its speciation. We aim to integrate selenium speciation and metabolism into a discussion of the mechanisms by which selenium exerts its biological activity. First, we present the current status of selenium in the prevention of cancer, cardiovascular and neurodegenerative diseases with particular attention paid to the results of major chemoprevention trials involving selenium supplementation. A comprehensive review of the current understanding of the metabolism of common dietary selenium compounds - selenite, selenomethionine, methylselenocysteine and selenocystine - is presented, with discussion of the evidence for the various metabolic pathways and their products. The antioxidant, prooxidant and other mechanisms of the dietary selenium compounds have been linked to their disease prevention and treatment properties. The evidence for these various mechanisms -in vitro, in cells and in vivo- is evaluated with emphasis on the selenium metabolites involved. We conclude that dietary selenium compounds should be considered prodrugs, whose biological activity will depend on the activity of the various metabolic pathways in, and the redox status of, cells and tissues. These factors should be considered in future laboratory research and in selecting selenium compounds for trials of disease prevention and treatment by selenium supplementation.

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Section: Downstream Metabolitesmentioning

confidence: 99%

“…). [94][95][96] See text for more detail on the methylation and excretion pathways. Abbreviations: DeMeT, demethyltransferases; MeT, methyltransferases; SPS, selenophosphate synthetase.…”

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confidence: 99%

Which form is that? The importance of selenium speciation and metabolism in the prevention and treatment of disease

2013

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“…A distinguishing feature of selenoproteins is that they contain Se in the form of selenocysteine (Sec). The amino acid selenocysteine does not come from a diet, but is synthesised in the reaction of phosphoserine charged to transfer RNA [Ser]Sec (O-phosphoseryltRNA [Ser]Sec ) with monoselenophosphate (selenium donor), which gives rise to selenocysteyl-tRNA [Ser] Sec , and is then specifically attached to the growing polypeptide chain (Glass et al 2008). So far, researchers have identified 25 selenoproteins in humans (Kryukov et al 2003).…”

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confidence: 99%

Selenium interactions and toxicity: a review

2011

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Selenium is an essential trace element for mammals. Through selenoproteins, this mineral participates in various biological processes such as antioxidant defence, thyroid hormone production, and immune responses. Some reports indicate that a human organism deficient in selenium may be prone to certain diseases. Adverse health effects following selenium overexposure, although very rare, have been found in animals and people. Contrary to selenium, arsenic and cadmium are regarded as toxic elements. Both are environmental and industrial pollutants, and exposure to excessive amounts of arsenic or cadmium can pose a threat to many people's health, especially those living in polluted regions. Two other elements, vanadium and chromium(III) in trace amounts are believed to play essential physiological functions in mammals. This review summarizes recent studies on selenium interactions with arsenic and cadmium and selenium interactions with vanadium and chromium in mammals. Human studies have demonstrated that selenium may reduce arsenic accumulation in the organism and protect against arsenic-related skin lesions. Selenium was found to antagonise the prooxidant and genotoxic effects of arsenic in rodents and cell cultures. Also, studies on selenium effects against oxidative stress induced by cadmium in various animal tissues produced promising results. Reports suggest that selenium protection against toxicity of arsenic and cadmium is mediated via sequestration of these elements into biologically inert conjugates. Selenium-dependent antioxidant enzymes probably play a secondary role in arsenic and cadmium detoxification. So far, few studies have evaluated selenium effects on chromium(III) and vanadium actions in mammals. Still, they show that selenium may interact with these minerals. Taken together, the recent findings regarding selenium interaction with other elements extend our understanding of selenium biological functions and highlight selenium as a potential countermeasure against toxicity induced by arsenic and cadmium.

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“…5,14,36,37 There is in vitro evidence that HSe À is involved in the synthesis of monoselenophosphate, which is considered to be the source of Se for selenoprotein synthesis. 16,[38][39][40][41] The speciation of Se in vivo has been explored in rat models, typically using hyphenated techniques that couple separation (chromatographic) to identification (mass spectrometric) techniques. The hyphenated techniques, typically high performance liquid chromatography-inductively coupled mass spectrometry (HPLC-ICP-MS), have been used to unequivocally identify some Se metabolites in cell lines, tissue homogenates and human urine, but many remain unidentified in vivo.…”

Section: Introductionmentioning

confidence: 99%

XAS and XFM studies of selenium and copper speciation and distribution in the kidneys of selenite-supplemented rats

et al. 2014

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Dietary selenium has been implicated in the prevention of cancer and other diseases, but its safety and efficacy is dependent on the supplemented form and its metabolites. In this study, X-ray absorption spectroscopy (XAS) and X-ray fluorescence microscopy (XFM) have been used to investigate the speciation and distribution of Se and Cu in vivo. In kidneys isolated from rats fed a diet containing 5 ppm Se as selenite for 3 weeks, Se levels increased 5-fold. XFM revealed a strong correlation between the distribution of Se and the distribution of Cu in the kidney, a phenomenon that has previously been observed in cell culture (Weekley et al., JBIC, J. Biol. Inorg. Chem., 2014, DOI: 10.1007/s00775-014-1113-x). However, X-ray absorption spectra suggest that most of the Se in the kidney is found as Se-Se species, rather than Cu-bound, and that most of the Cu is bound to S and N, presumably to amino acid residues in proteins. Furthermore, SOD1 expression did not change in response to the high Se diet. We cannot rule out the possibility of some Cu-Se bonding in the tissues, but our results suggest mechanisms other than the formation of Cu-Se species and SOD1 upregulation are responsible for the highly correlated distributions of Se and Cu in the kidneys of rats fed high selenite diets.

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Insights into the Chemical Biology of Selenium

Abstract: The long-sought pathway by which selenocysteyl-tRNA [Ser]

Cited by 7 publications

References 19 publications

Which form is that? The importance of selenium speciation and metabolism in the prevention and treatment of disease

Which form is that? The importance of selenium speciation and metabolism in the prevention and treatment of disease

Selenium interactions and toxicity: a review

XAS and XFM studies of selenium and copper speciation and distribution in the kidneys of selenite-supplemented rats

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