Four selenoproteins, protein biosynthesis, and Wnt signalling are particularly sensitive to limited selenium intake in mouse colon
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PROVIDER: PRJNA480871 | ENA |
REPOSITORIES: ENA
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Project description: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 (0.086mg Se/kg) or a selenium-adequate (0.15mg Se/kg) diet. After 6wk, 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.
2018-07-13 | GSE117025 | GEO
Project description: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.
2018-07-13 | GSE117026 | GEO
Project description:The trace element selenium (Se) plays an important role in thyroid hormone metabolism. Low Se intake is associated with atuoimmune hypothyroidism. The interaction of Se and Graves’ disease (GD) is only poorly characterized. We have investigated the importance of dietary Se supply for GD by performing a more in-depth analysis of a large cross-sectional study of 6152 participants from two counties within the Shaanxi Province, China, which are characterized by different habitual Se intakes, and studied the effects of different dietary Se supply (0.02, 0.18, 0.6 or 2.0 ppm Se) on disease development in a mouse model of GD. In the cross-sectional study, prevalence of GD in the two areas of different Se intake was similar, and the Se status of GD patients was not different from healthy control subjects. The dietary Se supply in the animal model was not affecting thyroid hormone levels, malondialdehyde concentrations, total antioxidant capacity or the titer of GD-causing TSH receptor autoantibodies (TRAb). Expression analysis of transcripts in spleen indicated regulatory effects of Se intake on genes implicated in the immune response, erythropoiesis and oxygen status. However, the humoral immune response including the ratio of CD4/CD8 or Th1/Th2 cells, and the concentration of Treg cells were similar between the experimental groups despite their varying Se intakes. Our data from both the epidemiological analysis and animal experiment do not indicate a major role of Se in the development of GD, and highlight that autoimmune hypothyroidism and GD differ in their relation to Se status.
2021-05-30 | GSE115152 | GEO
Project description:Role of Selenium Intake for Risk and Development of Graves’ Disease
| PRJNA473976 | ENA
Project description:New Zealand (NZ) has high bowel cancer rates, which the Bowel Screening Programme aims to reduce by early detection of bowel cancer and its precursor, adenomas (polyps). Bowel cancer and adenoma rates are higher in countries like NZ with low intake of the essential trace mineral selenium. Overseas, trials of selenium supplements reduced adenoma recurrence in people with low blood selenium, but not with high levels (where adding selenium increased health risks). Laboratory research explained this, and found certain types of selenium are safer and more effective. The optimal type and dose of selenium to use in NZ cancer prevention trials is not known.
The main objective of this trial is to evaluate which dose and type of selenium (either selenomethionine or methylselenocysteine) gives optimal selenium status to maximise cancer prevention without causing health problems from excessive selenium intake. We also want to see how much selenium is needed according to selenium blood levels before starting selenium in the trial. Side effects will be evaluated, as will recruitment rates.
This will determine the feasibility of developing a large randomised trial of selenium to reduce the recurrence rates for advanced adenomas in NZ.
This trial will recruit 60 patients from Middlemore and Waikato Hospitals with an advanced adenoma removed through the Bowel Screening Programme. Patients will take one selenium compound, dosed at 50 mcg/day for 6 weeks then 100 mcg/day for 6 weeks, and will have blood tests at baseline, then blood tests and evaluation of side effects at 6 weeks and 12 weeks.
| 2382551 | ecrin-mdr-crc
Project description:Methanococcus maripaludis utilizes selenocysteine-(Sec-) containing proteins (selenoproteins), mostly active in the organism’s primary energy metabolism, methanogenesis. Under selenium depletion, M. maripaludis employs a set of enzymes containing cysteine (Cys) instead of Sec. The genes coding for these Sec-/Cys-containing isoforms are the only genes known expression of which is influenced by the selenium status of the cell. Using quantitative proteomics and transcriptomics approx. 7% and 12%, respectively, of all genes/proteins were differentially expressed/synthesized in response to the selenium supply. Some of the genes identified involve methanogenesis, nitrogenase functions, and putative transporters. An increase of transcript abundance for putative transporters under selenium-depleted conditions indicated the organism’s effort to tap into alternative sources of selenium. Selenium sources M. maripaludis is known to utilize are selenite and dimethylselenide. To expand this list, a selenium responsive reporter strain was assessed with nine other, environmentally relevant selenium species. While some had a similar biological window as selenite, others were effectively utilized at lower concentrations. Conversely, selenate and seleno-amino acids were only utilized at unphysiologically high concentrations and two compounds were not utilized at all. To address the role of the selenium-regulated putative transporters in selenium transport, M. maripaludis mutant strains lacking one or two of the putative transporters were tested for the capability to utilize the different selenium species. Of the five putative transporters analyzed by loss-of-function mutagenesis, none appeared to be absolutely required for utilizing any of the selenium species tested, indicating they have redundant and/or overlapping specificities, or are not dedicated selenium transporters.
2024-03-27 | PXD047095 | Pride
Project description:Methylmercury (MeHg) is a well-known neurotoxicant, particularly harmful for the developing brain. Selenium is a nutrient previously shown to interact with MeHg, however the molecular mechanisms behind these interaction is not fully described. To explore the effect of selenium on MeHg, mice were exposed to selenomethionine (SeMet) and MeHg in a 2 x 3 full factorial design for 12 weeks. After termination, organs, including the brain, were collected for Hg and Se analysis. The hippocampus was collected and analysed using gel free proteomics and RNA sequencing (RNA-seq). The presence of SeMet reduced the amount of Hg in several organs, including the brain, while the level of Hg were increased in the feces. The presence of Hg also increased the concentration of selenium in liver and cortex. Proteomic and RNA-seq analyses showed that several known pathways of MeHg toxicity, such as oxidative stress, altered metabolism and calcium disruption were alleviated when SeMet were present. Our results suggest that SeMet can to a certain extent ameliorate the neurotoxic effects of MeHg in a mouse model. Although, whether this is due to decrease of body burden of Hg or through direct interactions with selenium in vivo remains unclear.
2020-08-29 | GSE135381 | GEO
Project description:Genome-wide expression analysis in C. Elegans grown in axenic media with low to toxic selenium concentrations We performed Affymetrix micorarray-based transcriptional profiling on wild-type C. Elegans Bristol N2 grown in low Se axenic media supplemented with five concentrations of selenium, from low to toxic, and harvested at the L4-larva stage.
2014-07-03 | GSE54011 | GEO
Project description:Selenium deficiency in mice is associated with pro-longevity mechanisms due to reduced amino acid levels and altered nutrient signaling
2019-05-29 | GSE129138 | GEO
Project description:In this study, juvenile rainbow trout were exposed four dietary doses of organic selenium (7.1, 10.7 19.5 and 31.8 mg/kg Selenium) over 60 days. The RNA was exctracted from liver tissue and used for further gene expression analysis.
2015-06-30 | GSE67599 | GEO