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Selenoprotein P (selenoprotein + p)
Selected AbstractsSelenium and selenoproteins in the brain and brain diseasesJOURNAL OF NEUROCHEMISTRY, Issue 1 2003Jun Chen Abstract Over the past three decades, selenium has been intensively investigated as an antioxidant trace element. It is widely distributed throughout the body, but is particularly well maintained in the brain, even upon prolonged dietary selenium deficiency. Changes in selenium concentration in blood and brain have been reported in Alzheimer's disease and brain tumors. The functions of selenium are believed to be carried out by selenoproteins, in which selenium is specifically incorporated as the amino acid, selenocysteine. Several selenoproteins are expressed in brain, but many questions remain about their roles in neuronal function. Glutathione peroxidase has been localized in glial cells, and its expression is increased surrounding the damaged area in Parkinson's disease and occlusive cerebrovascular disease, consistent with its protective role against oxidative damage. Selenoprotein P has been reported to possess antioxidant activities and the ability to promote neuronal cell survival. Recent studies in cell culture and gene knockout models support a function for selenoprotein P in delivery of selenium to the brain. mRNAs for other selenoproteins, including selenoprotein W, thioredoxin reductases, 15-kDa selenoprotein and type 2 iodothyronine deiodinase, are also detected in the brain. Future research directions will surely unravel the important functions of this class of proteins in the brain. [source] Modulation of selenoprotein P expression by TGF-,1 is mediated by Smad proteinsBIOFACTORS, Issue 1-4 2001Volker Mostert Abstract Selenoprotein P (SeP) is a selenium-rich plasma protein which accounts for more than 50% this study, the effect of TGF-,1 on the expression of SeP in the human liver cell line HepG2 was investigated. Western analysis revealed a dose-dependent reduction of SeP content in cell supernatant. RT-PCR analysis of SeP-mRNA expression demonstrated a marked inhibition and a reporter gene under control of the SeP promoter was negatively regulated by TGF-,1. Smad proteins are the transcriptional mediators of TGF-, signaling. A putative Smad-binding element (SBE) is present in the SeP promoter. In electrophoretic-mobility-shift assays, TGF-,1 enhanced the binding of nuclear proteins to this SBE. Overexpression of Smad3 and 4 resulted in a downregulation of SeP-promoter activity whereas deletion of the SBE led to a loss of TGF-,1 responsiveness. We conclude that SeP expression is modulated by the binding of Smad3/4 complexes to a functional SBE in the SeP promoter. [source] Selenium and selenoproteins in the brain and brain diseasesJOURNAL OF NEUROCHEMISTRY, Issue 1 2003Jun Chen Abstract Over the past three decades, selenium has been intensively investigated as an antioxidant trace element. It is widely distributed throughout the body, but is particularly well maintained in the brain, even upon prolonged dietary selenium deficiency. Changes in selenium concentration in blood and brain have been reported in Alzheimer's disease and brain tumors. The functions of selenium are believed to be carried out by selenoproteins, in which selenium is specifically incorporated as the amino acid, selenocysteine. Several selenoproteins are expressed in brain, but many questions remain about their roles in neuronal function. Glutathione peroxidase has been localized in glial cells, and its expression is increased surrounding the damaged area in Parkinson's disease and occlusive cerebrovascular disease, consistent with its protective role against oxidative damage. Selenoprotein P has been reported to possess antioxidant activities and the ability to promote neuronal cell survival. Recent studies in cell culture and gene knockout models support a function for selenoprotein P in delivery of selenium to the brain. mRNAs for other selenoproteins, including selenoprotein W, thioredoxin reductases, 15-kDa selenoprotein and type 2 iodothyronine deiodinase, are also detected in the brain. Future research directions will surely unravel the important functions of this class of proteins in the brain. [source] Genistein affects androgen-responsive genes through both androgen- and estrogen-induced signaling pathways,MOLECULAR CARCINOGENESIS, Issue 1 2006Yoko Takahashi Abstract This study examined the mechanisms by which the prostate cancer chemopreventive agent genistein modulates gene expression in LNCaP human prostate cancer cells. Expression of androgen- and estrogen-regulated genes was measured in LNCaP cells cultured in the presence or absence of hormonal stimulation and the presence or absence of genistein. Genistein strongly suppressed basal expression of androgen-responsive gene (ARG) mRNAs, including prostate-specific antigen (PSA) and Ste20-related proline-alanine-rich kinase (SPAK). However, genistein had little or no effect on basal expression of two other ARGs, ,2 -microglobulin (B2M) or selenoprotein P (SEPP1). Culturing LNCaP cells in the presence of the synthetic androgen R1881-induced increases in PSA, SPAK, B2M, and SEPP1 mRNA levels. The R1881-induced expression of these genes was uniformly blocked by genistein. For PSA and SPAK, genistein also blocked or downregulated 17,-estradiol-induced increases in mRNA expression. These results indicate that genistein selectively alters expression of ARG mRNAs in LNCaP cells through modulation of both androgen- and estrogen-induced signaling pathways. Published 2005 Wiley-Liss, Inc. [source] High-throughput quantification of selenium in individual serum proteins from a healthy human population using HPLC on-line with isotope dilution inductively coupled plasma-MSPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 19 2010Sophia Letsiou Abstract In this study, a method, based on dual column affinity chromatography hyphenated to isotope dilution inductively coupled plasma,quadrupole MS, was developed for selenium determination in selenoprotein P, glutathione peroxidase, and selenoalbumin in human serum samples from a group of healthy volunteers (n=399). Method improvement was achieved using methanol-enhanced isotope dilution which resulted in improved sensitivity and removal of isobaric interferences. Although no human serum reference materials are currently certified for their selenium species levels, method development was conducted using human serum reference material BCR 637 and 639 as their Se species content has been reported in the previous studies, and thus comparisons were possible. The mean selenium concentrations determined for the 399 healthy volunteer serum samples were 23±10,ng Se mL,1 for glutathione peroxidase, 49±15,ng Se mL,1 for selenoprotein P and 11±4,ng Se mL,1 for selenoalbumin. These values are found to be in close agreement with published values for a limited number of healthy volunteer samples, and to establish baseline Se levels in serum proteins for an apparently healthy group of individuals, thus allowing for subsequent comparisons with respective values determined for groups of individuals with selenium related health issues, as well as assist in the discovery of potential selenium biomarkers. Also, the relationship between Se serum protein levels and some anthropometric characteristics of the volunteer population were investigated. Additionally, further development of the analytical method used in this study was achieved by adding a size exclusion chromatography column after the two affinity columns via a switching valve. This allowed for the separation of small selenium-containing molecules from glutathione peroxidase and thus enhanced the overall confidence in its identification. [source] New Approaches to Assess Selenium Status and RequirementNUTRITION REVIEWS, Issue 12 2000Jean Nève Ph.D. Selenium is one of the essential nutrients that may have beneficial effects on health at dietary intakes higher than the established Recommended Dietary Allowances in the United States. Dietary recommendations for this element have been the subject of much controversy, illustrating the difficulties involved in the definition of requirements based on the interpretation of biochemical markers. This review will show how concepts may differ and even change as a consequence of the evolution of the knowledge concerning classical parameters (e.g., identification of isoforms of the classical selenium-dependent enzyme glutathione peroxidase) or following the discovery of new biologic markers for selenium such as iodothyronine desiodinase, thioredoxin reductase, or the selenoproteins P and W. [source] | |||||||||||||