Artykuły w czasopismach: „Selenoproteins”

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Ghuge, Sandip A., Ulhas Sopanrao Kadam i Jong Chan Hong. "Selenoprotein: Potential Player in Redox Regulation in Chlamydomonas reinhardtii". Antioxidants 11, nr 8 (22.08.2022): 1630. http://dx.doi.org/10.3390/antiox11081630.

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Selenium (Se) is an essential micro-element for many organisms, including Chlamydomonas reinhardtii, and is required in trace amounts. It is obtained from the 21st amino acid selenocysteine (Sec, U), genetically encoded by the UGA codon. Proteins containing Sec are known as selenoproteins. In eukaryotes, selenoproteins are present in animals and algae, whereas fungi and higher plants lack them. The human genome contains 25 selenoproteins, most of which are involved in antioxidant defense activity, redox regulation, and redox signaling. In algae, 42 selenoprotein families were identified using various bioinformatics approaches, out of which C. reinhardtii is known to have 10 selenoprotein genes. However, the role of selenoproteins in Chlamydomonas is yet to be reported. Chlamydomonas selenoproteins contain conserved domains such as CVNVGC and GCUG, in the case of thioredoxin reductase, and CXXU in other selenoproteins. Interestingly, Sec amino acid residue is present in a catalytically active domain in Chlamydomonas selenoproteins, similar to human selenoproteins. Based on catalytical active sites and conserved domains present in Chlamydomonas selenoproteins, we suggest that Chlamydomonas selenoproteins could have a role in redox regulation and defense by acting as antioxidants in various physiological conditions.

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Dery, L., P. Sai Reddy, S. Dery, R. Mousa, O. Ktorza, A. Talhami i N. Metanis. "Accessing human selenoproteins through chemical protein synthesis". Chemical Science 8, nr 3 (2017): 1922–26. http://dx.doi.org/10.1039/c6sc04123j.

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The human body contains 25 selenoproteins, but challenges in their preparations have prevented biological characterizations thus far. Here we report the first total chemical syntheses of two human selenoproteins, selenoprotein M (SELM) and selenoprotein W (SELW).

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Sengupta, Aniruddha, Bradley A. Carlson, James A. Weaver, Sergey V. Novoselov, Dmitri E. Fomenko, Vadim N. Gladyshev i Dolph L. Hatfield. "A functional link between housekeeping selenoproteins and phase II enzymes". Biochemical Journal 413, nr 1 (12.06.2008): 151–61. http://dx.doi.org/10.1042/bj20080277.

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Sec (selenocysteine) is biosynthesized on its tRNA and incorporated into selenium-containing proteins (selenoproteins) as the 21st amino acid residue. Selenoprotein synthesis is dependent on Sec tRNA and the expression of this class of proteins can be modulated by altering Sec tRNA expression. The gene encoding Sec tRNA (Trsp) is a single-copy gene and its targeted removal in liver demonstrated that selenoproteins are essential for proper function wherein their absence leads to necrosis and hepatocellular degeneration. In the present study, we found that the complete loss of selenoproteins in liver was compensated for by an enhanced expression of several phase II response genes and their corresponding gene products. The replacement of selenoprotein synthesis in mice carrying mutant Trsp transgenes, wherein housekeeping, but not stress-related selenoproteins are expressed, led to normal expression of phase II response genes. Thus the present study provides evidence for a functional link between housekeeping selenoproteins and phase II enzymes.

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Capone, Francesca, Andrea Polo, Angela Sorice, Alfredo Budillon i Susan Costantini. "Integrated Analysis to Study the Relationship between Tumor-Associated Selenoproteins: Focus on Prostate Cancer". International Journal of Molecular Sciences 21, nr 18 (13.09.2020): 6694. http://dx.doi.org/10.3390/ijms21186694.

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Selenoproteins are proteins that contain selenium within selenocysteine residues. To date, twenty-five mammalian selenoproteins have been identified; however, the functions of nearly half of these selenoproteins are unknown. Although alterations in selenoprotein expression and function have been suggested to play a role in cancer development and progression, few detailed studies have been carried out in this field. Network analyses and data mining of publicly available datasets on gene expression levels in different cancers, and the correlations with patient outcome, represent important tools to study the correlation between selenoproteins and other proteins present in the human interactome, and to determine whether altered selenoprotein expression is cancer type-specific, and/or correlated with cancer patient prognosis. Therefore, in the present study, we used bioinformatics approaches to (i) build up the network of interactions between twenty-five selenoproteins and identify the most inter-correlated proteins/genes, which are named HUB nodes; and (ii) analyze the correlation between selenoprotein gene expression and patient outcome in ten solid tumors. Then, considering the need to confirm by experimental approaches the correlations suggested by the bioinformatics analyses, we decided to evaluate the gene expression levels of the twenty-five selenoproteins and six HUB nodes in androgen receptor-positive (22RV1 and LNCaP) and androgen receptor–negative (DU145 and PC3) cell lines, compared to human nontransformed, and differentiated, prostate epithelial cells (EPN) by RT-qPCR analysis. This analysis confirmed that the combined evaluation of some selenoproteins and HUB nodes could have prognostic value and may improve patient outcome predictions.

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Santesmasses, Didac, i Vadim N. Gladyshev. "Pathogenic Variants in Selenoproteins and Selenocysteine Biosynthesis Machinery". International Journal of Molecular Sciences 22, nr 21 (27.10.2021): 11593. http://dx.doi.org/10.3390/ijms222111593.

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Selenium is incorporated into selenoproteins as the 21st amino acid selenocysteine (Sec). There are 25 selenoproteins encoded in the human genome, and their synthesis requires a dedicated machinery. Most selenoproteins are oxidoreductases with important functions in human health. A number of disorders have been associated with deficiency of selenoproteins, caused by mutations in selenoprotein genes or Sec machinery genes. We discuss mutations that are known to cause disease in humans and report their allele frequencies in the general population. The occurrence of protein-truncating variants in the same genes is also presented. We provide an overview of pathogenic variants in selenoproteins genes from a population genomics perspective.

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Shimada, Briana K., Sydonie Swanson, Pamela Toh i Lucia A. Seale. "Metabolism of Selenium, Selenocysteine, and Selenoproteins in Ferroptosis in Solid Tumor Cancers". Biomolecules 12, nr 11 (28.10.2022): 1581. http://dx.doi.org/10.3390/biom12111581.

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A potential target of precision nutrition in cancer therapeutics is the micronutrient selenium (Se). Se is metabolized and incorporated as the amino acid selenocysteine (Sec) into 25 human selenoproteins, including glutathione peroxidases (GPXs) and thioredoxin reductases (TXNRDs), among others. Both the processes of Se and Sec metabolism for the production of selenoproteins and the action of selenoproteins are utilized by cancer cells from solid tumors as a protective mechanism against oxidative damage and to resist ferroptosis, an iron-dependent cell death mechanism. Protection against ferroptosis in cancer cells requires sustained production of the selenoprotein GPX4, which involves increasing the uptake of Se, potentially activating Se metabolic pathways such as the trans-selenation pathway and the TXNRD1-dependent decomposition of inorganic selenocompounds to sustain GPX4 synthesis. Additionally, endoplasmic reticulum-resident selenoproteins also affect apoptotic responses in the presence of selenocompounds. Selenoproteins may also help cancer cells adapting against increased oxidative damage and the challenges of a modified nutrient metabolism that result from the Warburg switch. Finally, cancer cells may also rewire the selenoprotein hierarchy and use Se-related machinery to prioritize selenoproteins that are essential to the adaptations against ferroptosis and oxidative damage. In this review, we discuss both the evidence and the gaps in knowledge on how cancer cells from solid tumors use Se, Sec, selenoproteins, and the Se-related machinery to promote their survival particularly via resistance to ferroptosis.

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Zhang, Ying, Yeon Jin Roh, Seong-Jeong Han, Iha Park, Hae Min Lee, Yong Sik Ok, Byung Cheon Lee i Seung-Rock Lee. "Role of Selenoproteins in Redox Regulation of Signaling and the Antioxidant System: A Review". Antioxidants 9, nr 5 (5.05.2020): 383. http://dx.doi.org/10.3390/antiox9050383.

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Selenium is a vital trace element present as selenocysteine (Sec) in proteins that are, thus, known as selenoproteins. Humans have 25 selenoproteins, most of which are functionally characterized as oxidoreductases, where the Sec residue plays a catalytic role in redox regulation and antioxidant activity. Glutathione peroxidase plays a pivotal role in scavenging and inactivating hydrogen and lipid peroxides, whereas thioredoxin reductase reduces oxidized thioredoxins as well as non-disulfide substrates, such as lipid hydroperoxides and hydrogen peroxide. Selenoprotein R protects the cell against oxidative damage by reducing methionine-R-sulfoxide back to methionine. Selenoprotein O regulates redox homeostasis with catalytic activity of protein AMPylation. Moreover, endoplasmic reticulum (ER) membrane selenoproteins (SelI, K, N, S, and Sel15) are involved in ER membrane stress regulation. Selenoproteins containing the CXXU motif (SelH, M, T, V, and W) are putative oxidoreductases that participate in various cellular processes depending on redox regulation. Herein, we review the recent studies on the role of selenoproteins in redox regulation and their physiological functions in humans, as well as their role in various diseases.

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Stanishevska, N. V. "Selenoproteins and their emerging roles in signaling pathways". Regulatory Mechanisms in Biosystems 11, nr 2 (23.04.2020): 186–99. http://dx.doi.org/10.15421/022028.

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The functional activity of selenoproteins has a wide range of effects on complex pathogenetic processes, including teratogenesis, immuno-inflammatory, neurodegenerative. Being active participants and promoters of many signaling pathways, selenoproteins support the lively interest of a wide scientific community. This review is devoted to the analysis of recent data describing the participation of selenoproteins in various molecular interactions mediating important signaling pathways. Data processing was carried out by the method of complex analysis. For convenience, all selenoproteins were divided into groups depending on their location and function. Among the group of selenoproteins of the ER membrane, selenoprotein N affects the absorption of Ca2+ by the endoplasmic reticulum mediated by oxidoreductin (ERO1), a key player in the CHOP/ERO1 branch, a pathogenic mechanism that causes myopathy. Another selenoprotein of the ER membrane selenoprotein K binding to the DHHC6 protein affects the IP3R receptor that regulates Ca2+ flux. Selenoprotein K is able to affect another protein of the endoplasmic reticulum CHERP, also appearing in Ca2+ transport. Selenoprotein S, associated with the lumen of ER, is able to influence the VCP protein, which ensures the incorporation of selenoprotein K into the ER membrane. Selenoprotein M, as an ER lumen protein, affects the phosphorylation of STAT3 by leptin, which confirms that Sel M is a positive regulator of leptin signaling. Selenoprotein S also related to luminal selenoproteins ER is a modulator of the IRE1α-sXBP1 signaling pathway. Nuclear selenoprotein H will directly affect the suppressor of malignant tumours, p53 protein, the activation of which increases with Sel H deficiency. The same selenoprotein is involved in redox regulation. Among the cytoplasmic selenoproteins, abundant investigations are devoted to SelP, which affects the PI3K/Akt/Erk signaling pathway during ischemia/reperfusion, is transported into the myoblasts through the plasmalemma after binding to the apoER2 receptor, and into the neurons to the megaline receptor and in general, selenoprotein P plays the role of a pool that stores the necessary trace element and releases it, if necessary, for vital selenoproteins. The thioredoxin reductase family plays a key role in the invasion and metastasis of salivary adenoid cystic carcinoma through the influence on the TGF-β-Akt/GSK-3β pathway during epithelial-mesenchymal transition. The deletion of thioredoxin reductase 1 affects the levels of messengers of the Wnt/β-catenin signaling pathway. No less studied is the glutathione peroxidase group, of which GPX3 is able to inhibit signaling in the Wnt/β-catenin pathway and thereby inhibit thyroid metastasis, as well as suppress protein levels in the PI3K/Akt/c-fos pathway. A key observation is that in cases of carcinogenesis, a decrease in GPX3 and its hypermethylation are almost always found. Among deiodinases, deiodinase 3 acts as a promoter of the oncogenes BRAF, MEK or p38, while stimulating a decrease in the expression of cyclin D1. The dependence of the level of deiodinase 3 on the Hedgehog (SHH) signaling pathway is also noted. Methionine sulfoxide reductase A can compete for the uptake of ubiquitin, reduce p38, JNK and ERK promoters of the MAPK signaling pathway; methionine sulfoxide reductase B1 suppresses MAPK signaling messengers, and also increases PARP and caspase 3.

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Addinsall, Alex B., Craig R. Wright, Sof Andrikopoulos, Chris van der Poel i Nicole Stupka. "Emerging roles of endoplasmic reticulum-resident selenoproteins in the regulation of cellular stress responses and the implications for metabolic disease". Biochemical Journal 475, nr 6 (20.03.2018): 1037–57. http://dx.doi.org/10.1042/bcj20170920.

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Chronic metabolic stress leads to cellular dysfunction, characterized by excessive reactive oxygen species, endoplasmic reticulum (ER) stress and inflammation, which has been implicated in the pathogenesis of obesity, type 2 diabetes and cardiovascular disease. The ER is gaining recognition as a key organelle in integrating cellular stress responses. ER homeostasis is tightly regulated by a complex antioxidant system, which includes the seven ER-resident selenoproteins — 15 kDa selenoprotein, type 2 iodothyronine deiodinase and selenoproteins S, N, K, M and T. Here, the findings from biochemical, cell-based and mouse studies investigating the function of ER-resident selenoproteins are reviewed. Human experimental and genetic studies are drawn upon to highlight the relevance of these selenoproteins to the pathogenesis of metabolic disease. ER-resident selenoproteins have discrete roles in the regulation of oxidative, ER and inflammatory stress responses, as well as intracellular calcium homeostasis. To date, only two of these ER-resident selenoproteins, selenoproteins S and N have been implicated in human disease. Nonetheless, the potential of all seven ER-resident selenoproteins to ameliorate metabolic dysfunction warrants further investigation.

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Yao, Haidong, Wei Liu, Wenchao Zhao, Ruifeng Fan, Xia Zhao, Pervez Ahmed Khoso, Ziwei Zhang i Shiwen Xu. "Different responses of selenoproteins to the altered expression of selenoprotein W in chicken myoblasts". RSC Adv. 4, nr 109 (2014): 64032–42. http://dx.doi.org/10.1039/c4ra11502c.

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Stanishevska, N. V. "Modern concept of biological identification of selenoproteins". Regulatory Mechanisms in Biosystems 9, nr 4 (19.10.2018): 553–60. http://dx.doi.org/10.15421/021883.

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Humans possess 25 selenoproteins, approximately half of which are enzymes (selenoenzymes) required for preventing, regulating, or reversing oxidative damage, while others participate in providing calcium metabolism, thyroid hormone maintenance, protein synthesis, cytoskeletal structure etc. This review examines the latest evidences of the biological effects of selenoproteins according to the method of complex analysis of the material. Selenoprotein P promotes insulin resistance in type 2 diabetes, mediates myocardial ischemic-reperfusion injuries and provides protection against disease by reducing chronic oxidative stress. Selenoprotein T is expressed at the endoplasmic reticulum membrane in all cells during development, but is confined to endocrine tissues in adulthood, controls homeostasis of glucose and prevents neurodegeneration by reducing oxidative stress factors. Expression of selenoprotein K is required for efficient Ca2+ flux into melanoma cancer cells, tumour growth and metastasic potential depend on SelK but it suppresses human choriocarcinoma cells. SelK also serves to maintain the normal physiological functions of skeletal muscle. Selenoprotein N deficiency, caused by mutations in the human gene, promotes myopathy characterized by muscle weakness, spinal rigidity, respiratory insufficiency. Sel N participates in normal physiology of skeletal and smooth muscle tissues. Selenoprotein M is located in the endoplasmic reticulum, characterized by high expression in the brain, antioxidative, neuroprotective activity and regulates intracellular Ca2+ levels. Also, the overexpression of SelM was detected in human hepatocellular carcinoma. Selenoprotein S is mentioned as a regulator of ER stress and inflammatory processes. Selenoprotein F controls cell proliferation by the impact on G1period of the cell cycle. Moreover, it is implicated in the pathogenesis of some types of cancer. The Sel F deficiency reduces the migration and invasive ability of the cells. Knockdown of selenoprotein W in rodents leads to increased release of Ca2+, causes oxidative ultramicroscopic injuries of the endoplasmic reticulum and mitochondria ultrastructure, which in turn increases the levels of inflammatory factors. Selenoprotein H is involved in redox regulation, in tumourogenesis. Knockdown of selenoprotein H decreases cellular differentiation and increases proliferation and migration of cells. Selenoproteins U, V, I, O, R are recently identified and their functions are not clearly known. The data analyzed in the review help determine promising directions in the study of the selenoproteins.

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Novoselov, Sergey V., Deame Hua, Alexey V. Lobanov i Vadim N. Gladyshev. "Identification and characterization of Fep15, a new selenocysteine-containing member of the Sep15 protein family". Biochemical Journal 394, nr 3 (24.02.2006): 575–79. http://dx.doi.org/10.1042/bj20051569.

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Sec (selenocysteine) is a rare amino acid in proteins. It is co-translationally inserted into proteins at UGA codons with the help of SECIS (Sec insertion sequence) elements. A full set of selenoproteins within a genome, known as the selenoproteome, is highly variable in different organisms. However, most of the known eukaryotic selenoproteins are represented in the mammalian selenoproteome. In addition, many of these selenoproteins have cysteine orthologues. Here, we describe a new selenoprotein, designated Fep15, which is distantly related to members of the 15 kDa selenoprotein (Sep15) family. Fep15 is absent in mammals, can be detected only in fish and is present in these organisms only in the selenoprotein form. In contrast with other members of the Sep15 family, which contain a putative active site composed of Sec and cysteine, Fep15 has only Sec. When transiently expressed in mammalian cells, Fep15 incorporated Sec in an SECIS- and SBP2 (SECIS-binding protein 2)-dependent manner and was targeted to the endoplasmic reticulum by its N-terminal signal peptide. Phylogenetic analyses of Sep15 family members suggest that Fep15 evolved by gene duplication.

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Handy, Diane E., Jacob Joseph i Joseph Loscalzo. "Selenium, a Micronutrient That Modulates Cardiovascular Health via Redox Enzymology". Nutrients 13, nr 9 (17.09.2021): 3238. http://dx.doi.org/10.3390/nu13093238.

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Selenium (Se) is a trace nutrient that promotes human health through its incorporation into selenoproteins in the form of the redox-active amino acid selenocysteine (Sec). There are 25 selenoproteins in humans, and many of them play essential roles in the protection against oxidative stress. Selenoproteins, such as glutathione peroxidase and thioredoxin reductase, play an important role in the reduction of hydrogen and lipid hydroperoxides, and regulate the redox status of Cys in proteins. Emerging evidence suggests a role for endoplasmic reticulum selenoproteins, such as selenoproteins K, S, and T, in mediating redox homeostasis, protein modifications, and endoplasmic reticulum stress. Selenoprotein P, which functions as a carrier of Se to tissues, also participates in regulating cellular reactive oxygen species. Cellular reactive oxygen species are essential for regulating cell growth and proliferation, protein folding, and normal mitochondrial function, but their excess causes cell damage and mitochondrial dysfunction, and promotes inflammatory responses. Experimental evidence indicates a role for individual selenoproteins in cardiovascular diseases, primarily by modulating the damaging effects of reactive oxygen species. This review examines the roles that selenoproteins play in regulating vascular and cardiac function in health and disease, highlighting their antioxidant and redox actions in these processes.

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Wolfram, Theresa, Leonie M. Weidenbach, Johanna Adolf, Maria Schwarz, Patrick Schädel, André Gollowitzer, Oliver Werz, Andreas Koeberle, Anna P. Kipp i Solveigh C. Koeberle. "The Trace Element Selenium Is Important for Redox Signaling in Phorbol Ester-Differentiated THP-1 Macrophages". International Journal of Molecular Sciences 22, nr 20 (14.10.2021): 11060. http://dx.doi.org/10.3390/ijms222011060.

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Physiological selenium (Se) levels counteract excessive inflammation, with selenoproteins shaping the immunoregulatory cytokine and lipid mediator profile. How exactly differentiation of monocytes into macrophages influences the expression of the selenoproteome in concert with the Se supply remains obscure. THP-1 monocytes were differentiated with phorbol 12-myristate 13-acetate (PMA) into macrophages and (i) the expression of selenoproteins, (ii) differentiation markers, (iii) the activity of NF-κB and NRF2, as well as (iv) lipid mediator profiles were analyzed. Se and differentiation affected the expression of selenoproteins in a heterogeneous manner. GPX4 expression was substantially decreased during differentiation, whereas GPX1 was not affected. Moreover, Se increased the expression of selenoproteins H and F, which was further enhanced by differentiation for selenoprotein F and diminished for selenoprotein H. Notably, LPS-induced expression of NF-κB target genes was facilitated by Se, as was the release of COX- and LOX-derived lipid mediators and substrates required for lipid mediator biosynthesis. This included TXB2, TXB3, 15-HETE, and 12-HEPE, as well as arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Our results indicate that Se enables macrophages to accurately adjust redox-dependent signaling and thereby modulate downstream lipid mediator profiles.

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Schoenmakers, Erik, i Krishna Chatterjee. "Human Genetic Disorders Resulting in Systemic Selenoprotein Deficiency". International Journal of Molecular Sciences 22, nr 23 (29.11.2021): 12927. http://dx.doi.org/10.3390/ijms222312927.

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Selenium, a trace element fundamental to human health, is incorporated as the amino acid selenocysteine (Sec) into more than 25 proteins, referred to as selenoproteins. Human mutations in SECISBP2, SEPSECS and TRU-TCA1-1, three genes essential in the selenocysteine incorporation pathway, affect the expression of most if not all selenoproteins. Systemic selenoprotein deficiency results in a complex, multifactorial disorder, reflecting loss of selenoprotein function in specific tissues and/or long-term impaired selenoenzyme-mediated defence against oxidative and endoplasmic reticulum stress. SEPSECS mutations are associated with a predominantly neurological phenotype with progressive cerebello-cerebral atrophy. Selenoprotein deficiency due to SECISBP2 and TRU-TCA1-1 defects are characterized by abnormal circulating thyroid hormones due to lack of Sec-containing deiodinases, low serum selenium levels (low SELENOP, GPX3), with additional features (myopathy due to low SELENON; photosensitivity, hearing loss, increased adipose mass and function due to reduced antioxidant and endoplasmic reticulum stress defence) in SECISBP2 cases. Antioxidant therapy ameliorates oxidative damage in cells and tissues of patients, but its longer term benefits remain undefined. Ongoing surveillance of patients enables ascertainment of additional phenotypes which may provide further insights into the role of selenoproteins in human biological processes.

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Dolgova, Natalia V., Susan Nehzati, Tracy C. MacDonald, Kelly L. Summers, Andrew M. Crawford, Patrick H. Krone, Graham N. George i Ingrid J. Pickering. "Disruption of selenium transport and function is a major contributor to mercury toxicity in zebrafish larvae". Metallomics 11, nr 3 (2019): 621–31. http://dx.doi.org/10.1039/c8mt00315g.

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Zhu, Kongdi, Shihui Yang, Tong Li, Xin Huang, Yulan Dong, Pengjie Wang i Jiaqiang Huang. "Advances in the Study of the Mechanism by Which Selenium and Selenoproteins Boost Immunity to Prevent Food Allergies". Nutrients 14, nr 15 (29.07.2022): 3133. http://dx.doi.org/10.3390/nu14153133.

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Selenium (Se) is an essential micronutrient that functions in the body mainly in the form of selenoproteins. The selenoprotein contains 25 members in humans that exhibit a number of functions. Selenoproteins have immunomodulatory functions and can enhance the ability of immune system to regulate in a variety of ways, which can have a preventive effect on immune-related diseases. Food allergy is a specific immune response that has been increasing in number in recent years, significantly reducing the quality of life and posing a major threat to human health. In this review, we summarize the current understanding of the role of Se and selenoproteins in regulating the immune system and how dysregulation of these processes may lead to food allergies. Thus, we can explain the mechanism by which Se and selenoproteins boost immunity to prevent food allergies.

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Bellinger, Frederick P., Arjun V. Raman, Mariclair A. Reeves i Marla J. Berry. "Regulation and function of selenoproteins in human disease". Biochemical Journal 422, nr 1 (29.07.2009): 11–22. http://dx.doi.org/10.1042/bj20090219.

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Selenoproteins are proteins containing selenium in the form of the 21st amino acid, selenocysteine. Members of this protein family have many diverse functions, but their synthesis is dependent on a common set of cofactors and on dietary selenium. Although the functions of many selenoproteins are unknown, several disorders involving changes in selenoprotein structure, activity or expression have been reported. Selenium deficiency and mutations or polymorphisms in selenoprotein genes and synthesis cofactors are implicated in a variety of diseases, including muscle and cardiovascular disorders, immune dysfunction, cancer, neurological disorders and endocrine function. Members of this unusual family of proteins have roles in a variety of cell processes and diseases.

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Guillin, Olivia, Caroline Vindry, Théophile Ohlmann i Laurent Chavatte. "Selenium, Selenoproteins and Viral Infection". Nutrients 11, nr 9 (4.09.2019): 2101. http://dx.doi.org/10.3390/nu11092101.

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Reactive oxygen species (ROS) are frequently produced during viral infections. Generation of these ROS can be both beneficial and detrimental for many cellular functions. When overwhelming the antioxidant defense system, the excess of ROS induces oxidative stress. Viral infections lead to diseases characterized by a broad spectrum of clinical symptoms, with oxidative stress being one of their hallmarks. In many cases, ROS can, in turn, enhance viral replication leading to an amplification loop. Another important parameter for viral replication and pathogenicity is the nutritional status of the host. Viral infection simultaneously increases the demand for micronutrients and causes their loss, which leads to a deficiency that can be compensated by micronutrient supplementation. Among the nutrients implicated in viral infection, selenium (Se) has an important role in antioxidant defense, redox signaling and redox homeostasis. Most of biological activities of selenium is performed through its incorporation as a rare amino acid selenocysteine in the essential family of selenoproteins. Selenium deficiency, which is the main regulator of selenoprotein expression, has been associated with the pathogenicity of several viruses. In addition, several selenoprotein members, including glutathione peroxidases (GPX), thioredoxin reductases (TXNRD) seemed important in different models of viral replication. Finally, the formal identification of viral selenoproteins in the genome of molluscum contagiosum and fowlpox viruses demonstrated the importance of selenoproteins in viral cycle.

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Sengupta, Aniruddha, Bradley A. Carlson, Vyacheslav M. Labunskyy, Vadim N. Gladyshev i Dolph L. Hatfield. "Selenoprotein T deficiency alters cell adhesion and elevates selenoprotein W expression in murine fibroblast cells". Biochemistry and Cell Biology 87, nr 6 (grudzień 2009): 953–61. http://dx.doi.org/10.1139/o09-064.

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Mammalian selenoproteins have diverse functions, cellular locations, and evolutionary histories, but all use the amino acid selenocysteine (Sec), often present in the enzyme’s active site. Only about half of mammalian selenoproteins have been functionally characterized, with most being oxidoreductases. The cellular role of selenoprotein T (SelT), manifesting a CxxU motif in a thioredoxin-like fold and localized to Golgi and the endoplasmic reticulum, is not known. To examine its biological function, we knocked down SelT expression in mouse fibroblast cells and found that SelT deficiency alters cell adhesion and enhances the expression of several oxidoreductase genes, while decreasing the expression of genes involved in cell structure organization, suggesting the involvement of SelT in redox regulation and cell anchorage. Furthermore, we found that the loss of SelT elevates expression of another selenoprotein, selenoprotein W (SepW1). SelT and SepW1 belong to the same protein family, suggesting that SepW1 may functionally compensate for SelT.

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Kim, Choon, i Kee-Hong Kim. "Selenate Prevents Adipogenesis through Induction of Selenoprotein S and Attenuation of Endoplasmic Reticulum Stress". Molecules 23, nr 11 (5.11.2018): 2882. http://dx.doi.org/10.3390/molecules23112882.

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The conversion of preadipocytes to adipocytes (adipogenesis) is a potential target to treat or prevent obesity. Selenate, an inorganic form of selenium, elicits diverse health benefits, mainly through its incorporation into selenoproteins. The individual roles of selenium and certain selenoproteins have been reported. However, the effects of selenate treatment on selenoproteins in adipocytes are unclear. In this study, the effects of selenate pretreatment on selenoprotein and endoplasmic reticulum (ER) stress during adipogenesis were examined in vitro. The selenate pretreatment dose-dependently suppressed the adipogenesis of 3T3-L1 preadipocytes. The selenate pretreatment at 50 μM for 24 h almost completely suppressed adipogenesis without cytotoxic effects. The expression of the adipogenic genes peroxisome proliferator-activated receptor gamma, CCAAT-enhancer binding protein alpha, and leptin was suppressed by selenate. This pretreatment also upregulated selenoprotein S (SEPS1), an ER resident selenoprotein that reduces ER stress, and prevented dexamethasone-induced SEPS1 degradation during the early stage of adipogenesis. The selenate-inhibited adipogenesis was associated with an attenuation of ER stress. The expression of the ER stress marker genes was upregulated during the early stage of differentiation, whereas the selenate pretreatment suppressed the mRNA expression of the XBP1 and C/EBP homologous protein. The collective data suggest a preventive role of selenate and SEPS1 in adipogenesis, and support a novel dietary approach to prevent obesity.

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Hofstee, Pierre, James S. M. Cuffe i Anthony V. Perkins. "Analysis of Selenoprotein Expression in Response to Dietary Selenium Deficiency During Pregnancy Indicates Tissue Specific Differential Expression in Mothers and Sex Specific Changes in the Fetus and Offspring". International Journal of Molecular Sciences 21, nr 6 (23.03.2020): 2210. http://dx.doi.org/10.3390/ijms21062210.

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The human selenoproteome is comprised of ~25 genes, which incorporate selenium, in the form of selenocysteine, into their structure. Since it is well known that selenium is important to maternal health and foetal development during pregnancy, this study aimed at defining the impact of selenium deficiency on maternal, placental, foetal and offspring selenoprotein gene expression. Female C57BL/6 mice were randomly allocated to control (>190 μg/kg) or low selenium (<50 μg/kg) diets four weeks prior to mating and throughout gestation. At embryonic day (E)18.5, pregnant mice were sacrificed followed by collection of maternal and foetal tissues. A subset of mice littered down, and offspring were monitored from postnatal day (PN) 8, weaned at PN24 and sacrificed at PN180, followed by tissue collection. Following RNA extraction, the expression of 14 selenoproteins was assessed with qPCR in liver, kidneys, muscle and placenta. Selenium deficiency downregulated expression (Ptrt < 0.05) of many selenoproteins in maternal tissues and the placenta. However, foetal selenoprotein expression was upregulated (Ptrt < 0.05) in all tissues, especially the kidneys. This was not reflected at PN180; however, a sexually dimorphic relationship in selenoprotein expression was observed in offspring. This study demonstrates the selenoproteome is sensitive to dietary selenium levels, which may be exacerbated by pregnancy. We concluded that transcriptional regulation of selenoproteins is complex and multifaceted, with expression exhibiting tissue-, age- and sex-specificities.

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Moustafa, Mohamed E., Bradley A. Carlson, Muhammad A. El-Saadani, Gregory V. Kryukov, Qi-An Sun, John W. Harney, Kristina E. Hill i in. "Selective Inhibition of Selenocysteine tRNA Maturation and Selenoprotein Synthesis in Transgenic Mice Expressing Isopentenyladenosine-Deficient Selenocysteine tRNA". Molecular and Cellular Biology 21, nr 11 (1.06.2001): 3840–52. http://dx.doi.org/10.1128/mcb.21.11.3840-3852.2001.

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ABSTRACT Selenocysteine (Sec) tRNA (tRNA[Ser]Sec) serves as both the site of Sec biosynthesis and the adapter molecule for donation of this amino acid to protein. The consequences on selenoprotein biosynthesis of overexpressing either the wild type or a mutant tRNA[Ser]Sec lacking the modified base, isopentenyladenosine, in its anticodon loop were examined by introducing multiple copies of the corresponding tRNA[Ser]Sec genes into the mouse genome. Overexpression of wild-type tRNA[Ser]Sec did not affect selenoprotein synthesis. In contrast, the levels of numerous selenoproteins decreased in mice expressing isopentenyladenosine-deficient (i6A−) tRNA[Ser]Sec in a protein- and tissue-specific manner. Cytosolic glutathione peroxidase and mitochondrial thioredoxin reductase 3 were the most and least affected selenoproteins, while selenoprotein expression was most and least affected in the liver and testes, respectively. The defect in selenoprotein expression occurred at translation, since selenoprotein mRNA levels were largely unaffected. Analysis of the tRNA[Ser]Sec population showed that expression of i6A− tRNA[Ser]Sec altered the distribution of the two major isoforms, whereby the maturation of tRNA[Ser]Sec by methylation of the nucleoside in the wobble position was repressed. The data suggest that the levels of i6A− tRNA[Ser]Sec and wild-type tRNA[Ser]Sec are regulated independently and that the amount of wild-type tRNA[Ser]Sec is determined, at least in part, by a feedback mechanism governed by the level of the tRNA[Ser]Sec population. This study marks the first example of transgenic mice engineered to contain functional tRNA transgenes and suggests that i6A−tRNA[Ser]Sec transgenic mice will be useful in assessing the biological roles of selenoproteins.

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ANEMA, Sue M., Simon W. WALKER, A. Forbes HOWIE, John R. ARTHUR, Fergus NICOL i Geoff J. BECKETT. "Thioredoxin reductase is the major selenoprotein expressed in human umbilical-vein endothelial cells and is regulated by protein kinase C". Biochemical Journal 342, nr 1 (10.08.1999): 111–17. http://dx.doi.org/10.1042/bj3420111.

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Damage to the endothelium by reactive oxygen species favours atherogenesis. Such damage can be prevented by selenium, which is thought to exert its actions through the expression of selenoproteins. The family of glutathione peroxidases (GPXs) may have antioxidant roles in the endothelium but other intracellular and extracellular selenoproteins with antioxidant actions may also be important. The selenoproteins expressed by cultured human umbilical-vein endothelial cells (HUVECs) were labelled with [75Se]selenite and separated using SDS/PAGE. HUVECs secreted no extracellular selenoproteins. There were distinct differences between the intracellular selenoprotein profile of 75Se-labelled HUVECs and those of other tissues. A single selenoprotein with a molecular mass of 58 kDa accounted for approx. 43% of the intracellular 75Se-labelled proteins in HUVECs. This protein was identified by Western blotting as the redox-active lipid-hydroperoxide-detoxifying selenoprotein, thioredoxin reductase (TR). TR expression in HUVECs was down-regulated by transiently exposing cells to the phorbol ester PMA for periods as short as 1 min. However, there was a delay of 48 h after PMA exposure before maximal down-regulation of TR was observed. The protein kinase C (PKC) inhibitor bisindolylmaleimide I hydrochloride had no effect on TR expression when added alone, but the agent prevented the down-regulation of TR expression seen with PMA. The calcium ionophore A23187 increased TR expression in HUVECs after a 12-h exposure, but the maximal effect was only observed after a 35-h exposure. These findings suggest that TR may be an important factor in the known ability of Se to protect HUVECs from peroxidative damage. Furthermore, the results also suggest that TR expression can be negatively regulated through PKC. It is possible that TR expression may be positively regulated by the calcium-signalling cascade, although TR induction by A23187 may be due to toxicity.

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Kiledjian, Nora T., Rushvi Shah, Michael B. Vetick i Paul R. Copeland. "The expression of essential selenoproteins during development requires SECIS-binding protein 2–like". Life Science Alliance 5, nr 5 (24.02.2022): e202101291. http://dx.doi.org/10.26508/lsa.202101291.

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The dietary requirement for selenium is based on its incorporation into selenoproteins, which contain the amino acid selenocysteine (Sec). The Sec insertion sequence (SECIS) is an RNA structure found in the 3′ UTR of all selenoprotein mRNAs, and it is required to convert in-frame UGA codons from termination to Sec-incorporating codons. SECIS-binding protein 2 (Sbp2) is required for Sec incorporation, but its paralogue, SECIS-binding protein 2–like (Secisbp2l), while conserved, has no known function. Here we determined the relative roles of Sbp2 and Secisbp2l by introducing CRISPR mutations in both genes in zebrafish. By monitoring selenoprotein synthesis with 75Se labeling during embryogenesis, we found that sbp2−/− embryos still make a select subset of selenoproteins but secisbp2l−/− embryos retain the full complement. Abrogation of both genes completely prevents selenoprotein synthesis and juveniles die at 14 days post fertilization. Embryos lacking Sbp2 are sensitive to oxidative stress and express the stress marker Vtg1. We propose a model where Secisbp2l is required to promote essential selenoprotein synthesis when Sbp2 activity is compromised.

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Rengby, Olle, Linda Johansson, Lars A. Carlson, Elena Serini, Alexios Vlamis-Gardikas, Per Kårsnäs i Elias S. J. Arnér. "Assessment of Production Conditions for Efficient Use of Escherichia coli in High-Yield Heterologous Recombinant Selenoprotein Synthesis". Applied and Environmental Microbiology 70, nr 9 (wrzesień 2004): 5159–67. http://dx.doi.org/10.1128/aem.70.9.5159-5167.2004.

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ABSTRACT The production of heterologous selenoproteins in Escherichia coli necessitates the design of a secondary structure in the mRNA forming a selenocysteine insertion sequence (SECIS) element compatible with SelB, the elongation factor for selenocysteine insertion at a predefined UGA codon. SelB competes with release factor 2 (RF2) catalyzing translational termination at UGA. Stoichiometry between mRNA, the SelB elongation factor, and RF2 is thereby important, whereas other expression conditions affecting the yield of recombinant selenoproteins have been poorly assessed. Here we expressed the rat selenoprotein thioredoxin reductase, with titrated levels of the selenoprotein mRNA under diverse growth conditions, with or without cotransformation of the accessory bacterial selA, selB, and selC genes. Titration of the selenoprotein mRNA with a pBAD promoter was performed in both TOP10 and BW27783 cells, which unexpectedly could not improve yield or specific activity compared to that achieved in our prior studies. Guided by principal component analysis, we instead discovered that the most efficient bacterial selenoprotein production conditions were obtained with the high-transcription T7lac-driven pET vector system in presence of the selA, selB, and selC genes, with induction of production at late exponential phase. About 40 mg of rat thioredoxin reductase with 50% selenocysteine content could thereby be produced per liter bacterial culture. These findings clearly illustrate the ability of E. coli to upregulate the selenocysteine incorporation machinery on demand and that this is furthermore strongly augmented in late exponential phase. This study also demonstrates that E. coli can indeed be utilized as cell factories for highly efficient production of heterologous selenoproteins such as rat thioredoxin reductase.

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Huang, W., B. Åkesson, B. G. Svensson, A. Schütz, R. F. Burk i S. Skerfving. "Selenoprotein P and glutathione peroxidase (EC1·11·1·9) in plasma as indices of selenium status in relation to the intake of fish". British Journal of Nutrition 73, nr 3 (marzec 1995): 455–61. http://dx.doi.org/10.1079/bjn19950047.

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Department of Occupational and Environmental Medicine, University of Lund, Lund, Sweden In Sweden fish is considered to be an important source of dietary Se. Therefore Se status was assessed in forty-one middle-aged men with widely varying fish consumption. Glutathione peroxidase (EC1·11·1·9) and selenoprotein P in plasma were measured by radioimmunoassay. Plasma Se among the men increased slightly with increasing consumption of fish, but no such increases in the concentrations of glutathione peroxidase and selenoprotein P in plasma were observed. Moreover, no correlation was found between plasma Se and glutathione peroxidase or selenoprotein P. Instead, glutathione peroxidase was significantly correlated with selenoprotein P (r0·73,P<0·001), indicating that both glutathione peroxidase and selenoprotein P were functional indicators of Se status in this group. The proportion of plasma Se located in glutathione peroxidase decreased with increasing plasma Se. The results suggest that the Se consumed from fish had no apparent effect on the amount of Se incorporated into the functional selenoproteins of plasma. It is concluded that in some cases selenoproteins may be better biological markers of Se status than the total concentration of Se.

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Lammi, Mikko, i Chengjuan Qu. "Selenium-Related Transcriptional Regulation of Gene Expression". International Journal of Molecular Sciences 19, nr 9 (8.09.2018): 2665. http://dx.doi.org/10.3390/ijms19092665.

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The selenium content of the body is known to control the expression levels of numerous genes, both so-called selenoproteins and non-selenoproteins. Selenium is a trace element essential to human health, and its deficiency is related to, for instance, cardiovascular and myodegenerative diseases, infertility and osteochondropathy called Kashin–Beck disease. It is incorporated as selenocysteine to the selenoproteins, which protect against reactive oxygen and nitrogen species. They also participate in the activation of the thyroid hormone, and play a role in immune system functioning. The synthesis and incorporation of selenocysteine occurs via a special mechanism, which differs from the one used for standard amino acids. The codon for selenocysteine is a regular in-frame stop codon, which can be passed by a specific complex machinery participating in translation elongation and termination. This includes a presence of selenocysteine insertion sequence (SECIS) in the 3′-untranslated part of the selenoprotein mRNAs. Nonsense-mediated decay is involved in the regulation of the selenoprotein mRNA levels, but other mechanisms are also possible. Recent transcriptional analyses of messenger RNAs, microRNAs and long non-coding RNAs combined with proteomic data of samples from Keshan and Kashin–Beck disease patients have identified new possible cellular pathways related to transcriptional regulation by selenium.

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Sordillo, Lorraine, Chris Corl i Jeffery Gandy. "Selenoproteins regulate oxidative stress and inflammatory phenotype of endothelial cells (P5132)". Journal of Immunology 190, nr 1_Supplement (1.05.2013): 58.20. http://dx.doi.org/10.4049/jimmunol.190.supp.58.20.

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Abstract Oxidative stress contributes to the pathology of inflammatory-based diseases by increasing the expression of vascular-derived adhesion molecules, cytokines and eicosanoids. Certain selenoproteins, such as glutathione peroxidase (GPX) and thioredoxin reductase, possess important antioxidant defense functions in endothelial cells that can counteract the damaging pro-inflammatory effects of oxidative stress. Using an oxidative stress model based on selenium (Se) deficiency in bovine aortic endothelial cells (BAEC), we sought to determine whether specific selenoproteins may contribute to the differential regulation of adhesion molecules, cytokines and eicosanoids during pro-oxidant challenge. Se supplementation reduced adhesion molecule expression, cyclooxygenase 2, and pro-inflammatory cytokine expression by BAEC when compared to Se-deficient BAEC. Subsequent results using GPX4 siRNA showed that this selenoprotein is at least partially responsible for controlling adhesion molecule expression and cytokine production during oxidative stress. These data provide evidence for the involvement of certain selenoproteins in the regulation of adhesion molecule expression, eicosanoid biosynthesis, and cytokine production in BAEC during pro-oxidant challenge. Further characterization of the role of selenoproteins in endothelial cell metabolism may provide new insights as to how Se may provide specific health benefits in combating inflammatory-based diseases.

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Qazi, Izhar Hyder, Christiana Angel, Haoxuan Yang, Evangelos Zoidis, Bo Pan, Zhenzheng Wu, Zhang Ming i in. "Role of Selenium and Selenoproteins in Male Reproductive Function: A Review of Past and Present Evidences". Antioxidants 8, nr 8 (2.08.2019): 268. http://dx.doi.org/10.3390/antiox8080268.

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Selenium (Se) is an important trace mineral having many essential roles at the cellular and organismal levels in animal and human health. The biological effects of Se are mainly carried out by selenoproteins (encoded by 25 genes in humans and 24 in mice). As an essential component of selenoproteins, Se performs structural and enzymic roles; in the latter context it is well known for its catalytic and antioxidative functions. Studies involving different animal models have added great value to our understanding regarding the potential implications of Se and selenoproteins in mammalian fertility and reproduction. In this review, we highlight the implications of selenoproteins in male fertility and reproduction followed by the characteristic biological functions of Se and selenoproteins associated with overall male reproductive function. It is evident from observations of past studies (both animal and human) that Se is essentially required for spermatogenesis and male fertility, presumably because of its vital role in modulation of antioxidant defense mechanisms and other essential biological pathways and redox sensitive transcription factors. However, bearing in mind the evidences from mainstream literature, it is also advisable to perform more studies focusing on the elucidation of additional roles played by the peculiar and canonical selenoproteins i.e., glutathione peroxidase 4 (GPX4) and selenoprotein P (SELENOP) in the male reproductive functions. Nevertheless, search for the elucidation of additional putative mechanisms potentially modulated by other biologically relevant selenoproteins should also be included in the scope of future studies. However, as for the implication of Se in fertility and reproduction in men, though a few clinical trials explore the effects of Se supplementation on male fertility, due to inconsistencies in the recruitment of subjects and heterogeneity of designs, the comparison of such studies is still complicated and less clear. Therefore, further research focused on the roles of Se and selenoproteins is awaited for validating the evidences at hand and outlining any therapeutic schemes intended for improving male fertility. As such, new dimensions could be added to the subject of male fertility and Se supplementation.

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Seeher, Sandra, Bradley A. Carlson, Angela C. Miniard, Eva K. Wirth, Yassin Mahdi, Dolph L. Hatfield, Donna M. Driscoll i Ulrich Schweizer. "Impaired selenoprotein expression in brain triggers striatal neuronal loss leading to co-ordination defects in mice". Biochemical Journal 462, nr 1 (24.07.2014): 67–75. http://dx.doi.org/10.1042/bj20140423.

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Selenoproteins contain the rare amino acid selenocysteine. Reduced selenium levels in the brain lead to a complex neurological phenotype affecting cortical and hippocampal GABAergic interneurons. Here we show that striatal interneuron density is reduced in mice with impaired selenoprotein expression.

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Tinkov, Alexey A., Olga P. Ajsuvakova, Tommaso Filippini, Ji-Chang Zhou, Xin Gen Lei, Eugenia R. Gatiatulina, Bernhard Michalke i in. "Selenium and Selenoproteins in Adipose Tissue Physiology and Obesity". Biomolecules 10, nr 4 (24.04.2020): 658. http://dx.doi.org/10.3390/biom10040658.

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Selenium (Se) homeostasis is tightly related to carbohydrate and lipid metabolism, but its possible roles in obesity development and in adipocyte metabolism are unclear. The objective of the present study is to review the current data on Se status in obesity and to discuss the interference between Se and selenoprotein metabolism in adipocyte physiology and obesity pathogenesis. The overview and meta-analysis of the studies on blood Se and selenoprotein P (SELENOP) levels, as well as glutathione peroxidase (GPX) activity in obese subjects, have yielded heterogenous and even conflicting results. Laboratory studies demonstrate that Se may modulate preadipocyte proliferation and adipogenic differentiation, and also interfere with insulin signaling, and regulate lipolysis. Knockout models have demonstrated that the selenoprotein machinery, including endoplasmic reticulum-resident selenoproteins together with GPXs and thioredoxin reductases (TXNRDs), are tightly related to adipocyte development and functioning. In conclusion, Se and selenoproteins appear to play an essential role in adipose tissue physiology, although human data are inconsistent. Taken together, these findings do not support the utility of Se supplementation to prevent or alleviate obesity in humans. Further human and laboratory studies are required to elucidate associations between Se metabolism and obesity.

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Brown, KM, i JR Arthur. "Selenium, selenoproteins and human health: a review". Public Health Nutrition 4, nr 2b (kwiecień 2001): 593–99. http://dx.doi.org/10.1079/phn2001143.

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AbstractSelenium is of fundamental importance to human health. It is an essential component of several major metabolic pathways, including thyroid hormone metabolism, antioxidant defence systems, and immune function. The decline in blood selenium concentration in the UK and other European Union countries has therefore several potential public health implications, particularly in relation to the chronic disease prevalence of the Western world such as cancer and cardiovascular disease. Ten years have elapsed since recommended dietary intakes of selenium were introduced on the basis of blood glutathione peroxidase activity. Since then 30 new selenoproteins have been identified, of which 15 have been purified to allow characterisation of their biological function. The long term health implications in relation to declining selenium intakes have not yet been thoroughly examined, yet the implicit importance of selenium to human health is recognised universally.Selenium is incorporated as selenocysteine at the active site of a wide range of selenoproteins. The four glutathione peroxidase enzymes (classical GP×1, gastrointestinal GP×2, plasma GP×3, phospholipid hydroperoxide GP×4)) which represent a major class of functionally important selenoproteins, were the first to be characterised.Thioredoxin reductase (TR) is a recently identified seleno-cysteine containing enzyme which catalyzes the NADPH dependent reduction of thioredoxin and therefore plays a regulatory role in its metabolic activity.Approximately 60% of Se in plasma is incorporated in selenoprotein P which contains 10 Se atoms per molecule as selenocysteine, and may serve as a transport protein for Se. However, selenoprotein-P is also expressed in many tissues which suggests that although it may facilitate whole body Se distribution, this may not be its sole function.A second major class of selenoproteins are the iodothyronine deiodinase enzymes which catalyse the 5′5-mono-deiodination of the prohormone thyroxine (T4) to the active thyroid hormone 3,3′5-triiodothyronine (T3).Sperm capsule selenoprotein is localised in the mid-peice portion of spermatozoa where it stabilises the integrity of the sperm flagella.Se intake effects tissue concentrations of selenoprotein W which is reported to be necessary for muscle metabolism.It is of great concern that the health implications of the decline in Se status in the UK over the past two decades have not been systematically investigated. It is well recognised that dietary selenium is important for a healthy immune response. There is also evidence that Se has a protective effect against some forms of cancer; that it may enhance male fertility; decrease cardiovascular disease mortality, and regulate the inflammatory mediators in asthma. The potential influence of Se on these chronic diseases within the European population are important considerations when assessing Se requirement.

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Zhao, Hanqing, Chengchen Xu, Tingting Wang i Junqiu Liu. "Biomimetic Construction of Artificial Selenoenzymes". Biomimetics 8, nr 1 (28.01.2023): 54. http://dx.doi.org/10.3390/biomimetics8010054.

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Selenium exists in the form of selenocysteines in selenoproteins and plays a pivotal role in the catalytic process of the antioxidative enzymes. In order to study the structural and functional properties of selenium in selenoproteins, explore the significance of the role of selenium in the fields of biology and chemistry, scientists conducted a series of artificial simulations on selenoproteins. In this review, we sum up the progress and developed strategies in the construction of artificial selenoenzyme. Using different mechanisms from different catalytic angles, selenium-containing catalytic antibodies, semi-synthetic selenonezyme, and the selenium-containing molecularly imprinted enzymes have been constructed. A variety of synthetic selenoenzyme models have been designed and constructed by selecting host molecules such as cyclodextrins, dendrimers, and hyperbranched polymers as the main scaffolds. Then, a variety of selenoprotein assemblies as well as cascade antioxidant nanoenzymes were built by using electrostatic interaction, metal coordination, and host–guest interaction. The unique redox properties of selenoenzyme glutathione peroxidase (GPx) can be reproduced.

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Sonet, Jordan, Maurine Mosca, Katarzyna Bierla, Karolina Modzelewska, Anna Flis-Borsuk, Piotr Suchocki, Iza Ksiazek i in. "Selenized Plant Oil Is an Efficient Source of Selenium for Selenoprotein Biosynthesis in Human Cell Lines". Nutrients 11, nr 7 (4.07.2019): 1524. http://dx.doi.org/10.3390/nu11071524.

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Selenium is an essential trace element which is incorporated in the form of a rare amino acid, the selenocysteine, into an important group of proteins, the selenoproteins. Among the twenty-five selenoprotein genes identified to date, several have important cellular functions in antioxidant defense, cell signaling and redox homeostasis. Many selenoproteins are regulated by the availability of selenium which mostly occurs in the form of water-soluble molecules, either organic (selenomethionine, selenocysteine, and selenoproteins) or inorganic (selenate or selenite). Recently, a mixture of selenitriglycerides, obtained by the reaction of selenite with sunflower oil at high temperature, referred to as Selol, was proposed as a novel non-toxic, highly bioavailable and active antioxidant and antineoplastic agent. Free selenite is not present in the final product since the two phases (water soluble and oil) are separated and the residual water-soluble selenite discarded. Here we compare the assimilation of selenium as Selol, selenite and selenate by various cancerous (LNCaP) or immortalized (HEK293 and PNT1A) cell lines. An approach combining analytical chemistry, molecular biology and biochemistry demonstrated that selenium from Selol was efficiently incorporated in selenoproteins in human cell lines, and thus produced the first ever evidence of the bioavailability of selenium from selenized lipids.

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Sonet, Jordan, Anne-Laure Bulteau, Zahia Touat-Hamici, Maurine Mosca, Katarzyna Bierla, Sandra Mounicou, Ryszard Lobinski i Laurent Chavatte. "Selenoproteome Expression Studied by Non-Radioactive Isotopic Selenium-Labeling in Human Cell Lines". International Journal of Molecular Sciences 22, nr 14 (7.07.2021): 7308. http://dx.doi.org/10.3390/ijms22147308.

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Selenoproteins, in which the selenium atom is present in the rare amino acid selenocysteine, are vital components of cell homeostasis, antioxidant defense, and cell signaling in mammals. The expression of the selenoproteome, composed of 25 selenoprotein genes, is strongly controlled by the selenium status of the body, which is a corollary of selenium availability in the food diet. Here, we present an alternative strategy for the use of the radioactive 75Se isotope in order to characterize the selenoproteome regulation based on (i) the selective labeling of the cellular selenocompounds with non-radioactive selenium isotopes (76Se, 77Se) and (ii) the detection of the isotopic enrichment of the selenoproteins using size-exclusion chromatography followed by inductively coupled plasma mass spectrometry detection. The reliability of our strategy is further confirmed by western blots with distinct selenoprotein-specific antibodies. Using our strategy, we characterized the hierarchy of the selenoproteome regulation in dose–response and kinetic experiments.

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Shetty, Sumangala P., Nora T. Kiledjian i Paul R. Copeland. "The selenoprotein P 3’ untranslated region is an RNA binding protein platform that fine tunes selenocysteine incorporation". PLOS ONE 17, nr 7 (29.07.2022): e0271453. http://dx.doi.org/10.1371/journal.pone.0271453.

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Selenoproteins contain the 21st amino acid, selenocysteine (Sec), which is incorporated at select UGA codons when a specialized hairpin sequence, the Sec insertion sequence (SECIS) element, is present in the 3’ UTR. Aside from the SECIS, selenoprotein mRNA 3’ UTRs are not conserved between different selenoproteins within a species. In contrast, the 3’-UTR of a given selenoprotein is often conserved across species, which supports the hypothesis that cis-acting elements in the 3’-UTR other than the SECIS exert post-transcriptional control on selenoprotein expression. In order to determine the function of one such SECIS context, we chose to focus on the plasma selenoprotein, SELENOP, which is required to maintain selenium homeostasis as a selenium transport protein that contains 10 Sec residues. It is unique in that its mRNA contains two SECIS elements in the context of a highly conserved 843-nucleotide 3’ UTR. Here we have used RNA affinity chromatography and identified PTBP1 as the major RNA binding protein that specifically interacts with the sequence between the two SECIS elements. We then used CRISPR/Cas9 genome editing to delete two regions surrounding the first SECIS element. We found that these sequences are involved in regulating SELENOP mRNA and protein levels, which are inversely altered as a function of selenium concentrations.

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Kawatani, Yukie, Takafumi Suzuki, Ritsuko Shimizu, Vincent P. Kelly i Masayuki Yamamoto. "Nrf2 and selenoproteins are essential for maintaining oxidative homeostasis in erythrocytes and protecting against hemolytic anemia". Blood 117, nr 3 (20.01.2011): 986–96. http://dx.doi.org/10.1182/blood-2010-05-285817.

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Abstract Reactive oxygen species (ROS) are highly destructive toward cellular macromolecules. However, moderate levels of ROS can contribute to normal cellular processes including signaling. Herein we evaluate the consequence of a pro-oxidant environment on hematopoietic homeostasis. The NF-E2 related factor 2 (Nrf2) transcription factor regulates genes related to ROS scavenging and detoxification. Nrf2 responds to altered cellular redox status, such as occurs with loss of antioxidant selenoproteins after deletion of the selenocysteine-tRNA gene (Trsp). Conditional knockout of the Trsp gene using Mx1-inducible Cre-recombinase leads to selenoprotein deficiency and anemia on a wild-type background, whereas Trsp:Nrf2 double deficiency dramatically exacerbates the anemia and increases intracellular hydrogen peroxide levels in erythroblasts. Results indicate that Nrf2 compensates for defective ROS scavenging when selenoproteins are lost from erythroid cells. We also observed thymus atrophy in single Trsp-conditional knockout mice, suggesting a requirement for selenoprotein function in T-cell differentiation within the thymus. Surprisingly, no changes were observed in the myelomonocytic or megakaryocytic populations. Therefore, our results show that selenoprotein activity and the Nrf2 gene battery are particularly important for oxidative homeostasis in erythrocytes and for the prevention of hemolytic anemia.

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Pei, Junrui, Wenqi Fu, Liu Yang, Zhiyi Zhang i Yang Liu. "Oxidative Stress Is Involved in the Pathogenesis of Keshan Disease (an Endemic Dilated Cardiomyopathy) in China". Oxidative Medicine and Cellular Longevity 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/474203.

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Oxidative stress and selenoprotein deficiency are thought to be associated with the pathogenesis of Keshan disease (KD). However, to our knowledge, the level of oxidative stress and expression of selenoproteins have not been investigated in the myocardium of patients with KD. In this study, 8-hydroxy-2-deoxy guanosine (8-OH-dG), a marker of oxidative stress, was used to assess the level of oxidative stress, and thioredoxin reductase 1 (TrxR1) and glutathione peroxidase 1 (GPx1) were assessed to reflect the level of selenoproteins. Myocardial samples from 8 patients with KD and 9 non-KD patients (controls) were immunohistochemically stained for 8-OH-dG, TrxR1, and GPx1. The staining intensities were subsequently quantified using Olympus Image-Pro Plus 6.0 software. The data showed that the positive rate of 8-OH-dG expression in myocardial nuclei was higher in the KD group (68.6%) than that in the control group (2.4%). In addition, a positive correlation between the positive rate of 8-OH-dG and the degree of myocardial damage was observed in the KD group. The distribution of TrxR1 and GPx-1 was not associated with the distribution of myocardial damage. The expression of these two selenoproteins was higher in the control group than that in the KD group. Our study represents the first report on the expression profiles of oxidative stress and selenoproteins in the myocardium of patients with KD. The level of oxidative stress significantly increased and was positively correlated with the degree of myocardial damage in patients with KD. The selenoproteins, TrxR1 and GPx1, may have a role in the pathogenesis of KD.

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Rengby, Olle, i Elias S. J. Arnér. "Titration and Conditional Knockdown of the prfB Gene in Escherichia coli: Effects on Growth and Overproduction of the Recombinant Mammalian Selenoprotein Thioredoxin Reductase". Applied and Environmental Microbiology 73, nr 2 (3.11.2006): 432–41. http://dx.doi.org/10.1128/aem.02019-06.

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ABSTRACT Release factor 2 (RF2), encoded by the prfB gene in Escherichia coli, catalyzes translational termination at UGA and UAA codons. Termination at UGA competes with selenocysteine (Sec) incorporation at Sec-dedicated UGA codons, and RF2 thereby counteracts expression of selenoproteins. prfB is an essential gene in E. coli and can therefore not be removed in order to increase yield of recombinant selenoproteins. We therefore constructed an E. coli strain with the endogenous chromosomal promoter of prfB replaced with the titratable PBAD promoter. Knockdown of prfB expression gave a bacteriostatic effect, while two- to sevenfold overexpression of RF2 resulted in a slightly lowered growth rate in late exponential phase. In a turbidostatic fermentor system the simultaneous impact of prfB knockdown on growth and recombinant selenoprotein expression was subsequently studied, using production of mammalian thioredoxin reductase as model system. This showed that lowering the levels of RF2 correlated directly with increasing Sec incorporation specificity, while also affecting total selenoprotein yield concomitant with a lower growth rate. This study thus demonstrates that expression of prfB can be titrated through targeted exchange of the native promoter with a PBAD-promoter and that knockdown of RF2 can result in almost full efficiency of Sec incorporation at the cost of lower total selenoprotein yield.

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Moghadaszadeh, Behzad, i Alan H. Beggs. "Selenoproteins and Their Impact on Human Health Through Diverse Physiological Pathways". Physiology 21, nr 5 (październik 2006): 307–15. http://dx.doi.org/10.1152/physiol.00021.2006.

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In the last few decades, the importance of selenium in human health has been the subject of numerous studies. It is believed that the physiological effects of selenium occur mainly through the function of selenoproteins, which incorporate selenium in the form of one or more selenocysteine residues. Recent advances in understanding the complex regulation of selenoprotein synthesis and functional characterization of several members of the selenoprotein family have contributed to an improved comprehension of the role(s) of selenium in human health and the great diversity of physiological pathways influenced by this trace element.

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Zhang, Yitong, Jiaxing Wang i Xiqing Liu. "LRRC19—A Bridge between Selenium Adjuvant Therapy and Renal Clear Cell Carcinoma: A Study Based on Datamining". Genes 11, nr 4 (17.04.2020): 440. http://dx.doi.org/10.3390/genes11040440.

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Kidney renal clear cell carcinoma (KIRC) is the most common and fatal subtype of renal cancer. Antagonistic associations between selenium and cancer have been reported in previous studies. Selenium compounds, as anti-cancer agents, have been reported and approved for clinical trials. The main active form of selenium in selenoproteins is selenocysteine (Sec). The process of Sec biosynthesis and incorporation into selenoproteins plays a significant role in biological processes, including anti-carcinogenesis. However, a comprehensive selenoprotein mRNA analysis in KIRC remains absent. In the present study, we examined all 25 selenoproteins and identified key selenoproteins, glutathione peroxidase 3 (GPX3) and type 1 iodothyronine deiodinase (DIO1), with the associated prognostic biomarker leucine-rich repeat containing 19 (LRRC19) in clear cell renal cell carcinoma cases from The Cancer Genome Atlas (TCGA) database. We performed validations for the key gene expression levels by two individual clear cell renal cell carcinoma cohorts, GSE781 and GSE6344, datasets from the Gene Expression Omnibus (GEO) database. Multivariate survival analysis demonstrated that low expression of LRRC19 was an independent risk factor for OS. Gene set enrichment analysis (GSEA) identified tyrosine metabolism, metabolic pathways, peroxisome, and fatty acid degradation as differentially enriched with the high LRRC19 expression in KIRC cases, which are involved in selenium therapy of clear cell renal cell carcinoma. In conclusion, low expression of LRRC19 was identified as an independent risk factor, which will advance our understanding concerning the selenium adjuvant therapy of clear cell renal cell carcinoma.

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Papp, Laura V., Jun Lu, Frank Striebel, Derek Kennedy, Arne Holmgren i Kum Kum Khanna. "The Redox State of SECIS Binding Protein 2 Controls Its Localization and Selenocysteine Incorporation Function". Molecular and Cellular Biology 26, nr 13 (1.07.2006): 4895–910. http://dx.doi.org/10.1128/mcb.02284-05.

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ABSTRACT Selenoproteins are central controllers of cellular redox homeostasis. Incorporation of selenocysteine (Sec) into selenoproteins employs a unique mechanism to decode the UGA stop codon. The process requires the Sec insertion sequence (SECIS) element, tRNASec, and protein factors including the SECIS binding protein 2 (SBP2). Here, we report the characterization of motifs within SBP2 that regulate its subcellular localization and function. We show that SBP2 shuttles between the nucleus and the cytoplasm via intrinsic, functional nuclear localization signal and nuclear export signal motifs and that its nuclear export is dependent on the CRM1 pathway. Oxidative stress induces nuclear accumulation of SBP2 via oxidation of cysteine residues within a redox-sensitive cysteine-rich domain. These modifications are efficiently reversed in vitro by human thioredoxin and glutaredoxin, suggesting that these antioxidant systems might regulate redox status of SBP2 in vivo. Depletion of SBP2 in cell lines using small interfering RNA results in a decrease in Sec incorporation, providing direct evidence for its requirement for selenoprotein synthesis. Furthermore, Sec incorporation is reduced substantially after treatment of cells with agents that cause oxidative stress, suggesting that nuclear sequestration of SBP2 under such conditions may represent a mechanism to regulate the expression of selenoproteins.

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Ren, Bingyu, Min Liu, Jiazuan Ni i Jing Tian. "Role of Selenoprotein F in Protein Folding and Secretion: Potential Involvement in Human Disease". Nutrients 10, nr 11 (2.11.2018): 1619. http://dx.doi.org/10.3390/nu10111619.

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Selenoproteins form a group of proteins of which its members contain at least one selenocysteine, and most of them serve oxidoreductase functions. Selenoprotein F (SELENOF), one of the 25 currently identified selenoproteins, is located in the endoplasmic reticulum (ER) organelle and is abundantly expressed in many tissues. It is regulated according to its selenium status, as well as by cell stress conditions. SELENOF may be functionally linked to protein folding and the secretion process in the ER. Several studies have reported positive associations between SELENOF genetic variations and several types of cancer. Also, altered expression levels of SELENOF have been found in cancer cases and neurodegenerative diseases. In this review, we summarize the current understanding of the structure, expression, and potential function of SELENOF and discuss its possible relation with various pathological processes.

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Milanovic, Svetlana, Ivan Jovanovic i Olivera Valcic. "Selenoproteins". Veterinarski glasnik 69, nr 1-2 (2015): 75–89. http://dx.doi.org/10.2298/vetgl1502075m.

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Selenium is an essential trace element with multi significant role in the body. In contrast to other trace elements that appear as cofactors of certain enzymes, its physiological role is directly related to functions of proteins in composition of which it is cotranslationally installed by atypical amino acid selenocysteine. The group of proteins, in which composition selenocysteine is an integral functional part of polypeptides, are referred to as selenoproteins. The first enzyme that has been proven to have selenocysteine incorporated in its composition, is glutathione peroxidase (GPx). So far there have been identified 5 isoenzyme forms of GPx which reduce hydrogen peroxide and organic hydroperoxides, protecting cells from oxidative damage. Iodothyronine deiodinases (ID) are among the most important selenopoteins, being responsible for both activation and deactivation of thyroid hormones. So far there have been found over twenty selenoproteins, but only for some of them a physiological role is known.

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Lu, Jun, i Arne Holmgren. "Selenoproteins". Journal of Biological Chemistry 284, nr 2 (29.08.2008): 723–27. http://dx.doi.org/10.1074/jbc.r800045200.

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Caţianis, Alexandra Gabriela, Bogdana Virgolici, Beatrice Carmen Dogaru, Horia Virgolici i Maria Mohora. "From Selenium to Selenoproteins and their Role - Minireview". Acta Medica Transilvanica 25, nr 3 (1.09.2020): 56–59. http://dx.doi.org/10.2478/amtsb-2020-0052.

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AbstractSelenium (SE) is an essential micronutrient fulfilling a number of biological roles, being integrated as selenocysteine in the primary structure of certain selenoproteins. The Selenocysteine is synthesized and inserted into proteins during the translational process of the RNAm by a mechanism which involves converting a stop codon for certain proteins into a meaningful codon. Only 25 genes encoding selenocysteine-incorporating proteins have been identified in the human genome. The selenoprotein families including glutathione peroxidase, iodothyronine deiodinase and thioredoxin reductases are known as enzymes engaged in redox processes. The selenoprotein P (SEPP1) is a hepatokine produced by the liver, an extracellular glycoprotein, which is not part of these families. The purpose of this Article is to present the form of distribution of selenium and its physiological role in the body.

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Arnér, Elias S. J. "Common modifications of selenocysteine in selenoproteins". Essays in Biochemistry 64, nr 1 (23.12.2019): 45–53. http://dx.doi.org/10.1042/ebc20190051.

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Abstract Selenocysteine (Sec), the sulfur-to-selenium substituted variant of cysteine (Cys), is the defining entity of selenoproteins. These are naturally expressed in many diverse organisms and constitute a unique class of proteins. As a result of the physicochemical characteristics of selenium when compared with sulfur, Sec is typically more reactive than Cys while participating in similar reactions, and there are also some qualitative differences in the reactivities between the two amino acids. This minireview discusses the types of modifications of Sec in selenoproteins that have thus far been experimentally validated. These modifications include direct covalent binding through the Se atom of Sec to other chalcogen atoms (S, O and Se) as present in redox active molecular motifs, derivatization of Sec via the direct covalent binding to non-chalcogen elements (Ni, Mb, N, Au and C), and the loss of Se from Sec resulting in formation of dehydroalanine. To understand the nature of these Sec modifications is crucial for an understanding of selenoprotein reactivities in biological, physiological and pathophysiological contexts.

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Hughes, David, Tereza Kunická, Lutz Schomburg, Václav Liška, Niall Swan i Pavel Souček. "Expression of Selenoprotein Genes and Association with Selenium Status in Colorectal Adenoma and Colorectal Cancer". Nutrients 10, nr 11 (21.11.2018): 1812. http://dx.doi.org/10.3390/nu10111812.

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Dietary selenium (Se) intake is essential for synthesizing selenoproteins that are important in countering oxidative and inflammatory processes linked to colorectal carcinogenesis. However, there is limited knowledge on the selenoprotein expression in colorectal adenoma (CRA) and colorectal cancer (CRC) patients, or the interaction with Se status levels. We studied the expression of seventeen Se pathway genes (including fifteen of the twenty-five human selenoproteins) in RNA extracted from disease-normal colorectal tissue pairs, in the discovery phase of sixty-two CRA/CRC patients from Ireland and a validation cohort of a hundred and five CRC patients from the Czech Republic. Differences in transcript levels between the disease and paired control mucosa were assessed by the Mann-Whitney U-test. GPX2 and TXNRD3 showed a higher expression and GPX3, SELENOP, SELENOS, and SEPHS2 exhibited a lower expression in the disease tissue from adenomas and both cancer groups (p-values from 0.023 to <0.001). In the Czech cohort, up-regulation of GPX1, SELENOH, and SOD2 and down-regulation of SELENBP1, SELENON, and SELENOK (p-values 0.036 to <0.001) was also observed. We further examined the correlation of gene expression with serum Se status (assessed by Se and selenoprotein P, SELENOP) in the Irish patients. While there were no significant correlations with both Se status markers, SELENOF, SELENOK, and TXNRD1 tumor tissue expression positively correlated with Se, while TXNRD2 and TXNRD3 negatively correlated with SELENOP. In an analysis restricted to the larger Czech CRC patient cohort, Cox regression showed no major association of transcript levels with patient survival, except for an association of higher SELENOF gene expression with both a lower disease-free and overall survival. Several selenoproteins were differentially expressed in the disease tissue compared to the normal tissue of both CRA and CRC patients. Altered selenoprotein expression may serve as a marker of functional Se status and colorectal adenoma to cancer progression.

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Sasuclark, Alexandru R., Vedbar S. Khadka i Matthew W. Pitts. "Cell-Type Specific Analysis of Selenium-Related Genes in Brain". Antioxidants 8, nr 5 (5.05.2019): 120. http://dx.doi.org/10.3390/antiox8050120.

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Selenoproteins are a unique class of proteins that play key roles in redox signaling in the brain. This unique organ is comprised of a wide variety of cell types that includes excitatory neurons, inhibitory neurons, astrocytes, microglia, and oligodendrocytes. Whereas selenoproteins are known to be required for neural development and function, the cell-type specific expression of selenoproteins and selenium-related machinery has yet to be systematically investigated. Due to advances in sequencing technology and investment from the National Institutes of Health (NIH)-sponsored BRAIN initiative, RNA sequencing (RNAseq) data from thousands of cortical neurons can now be freely accessed and searched using the online RNAseq data navigator at the Allen Brain Atlas. Hence, we utilized this newly developed tool to perform a comprehensive analysis of the cell-type specific expression of selenium-related genes in brain. Select proteins of interest were further verified by means of multi-label immunofluorescent labeling of mouse brain sections. Of potential significance to neural selenium homeostasis, we report co-expression of selenoprotein P (SELENOP) and selenium binding protein 1 (SELENBP1) within astrocytes. These findings raise the intriguing possibility that SELENBP1 may negatively regulate astrocytic SELENOP synthesis and thereby limit downstream Se supply to neurons.

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