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Bai YZ, Zhang Y, Zhang SQ. New horizons for the role of selenium on cognitive function: advances and challenges. Metab Brain Dis 2024:10.1007/s11011-024-01375-y. [PMID: 38963634 DOI: 10.1007/s11011-024-01375-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 07/01/2024] [Indexed: 07/05/2024]
Abstract
Cognitive deficits associated with oxidative stress and the dysfunction of the central nervous system are present in some neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Selenium (Se), an essential microelement, exhibits cognition-associated functions through selenoproteins mainly owing to its antioxidant property. Due to the disproportionate distribution of Se in the soil, the amount of Se varies greatly in various foods, resulting in a large proportion of people with Se deficiency worldwide. Numerous cell and animal experiments demonstrate Se deficiency-induced cognitive deficits and Se supplementation-improved cognitive performances. However, human studies yield inconsistent results and the mechanism of Se in cognition still remains elusive, which hinder the further exploration of Se in human cognition. To address the urgent issue, the review summarizes Se-contained foods (plant-based foods, animal-based foods, and Se supplements), brain selenoproteins, mechanisms of Se in cognition (improvement of synaptic plasticity, regulation of Zn2+ level, inhibition of ferroptosis, modulation of autophagy and de novo synthesis of L-serine), and effects of Se on cognitive deficits, as well as consequently sheds light on great potentials of Se in the prevention and treatment of cognitive deficits.
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Affiliation(s)
- Ya-Zhi Bai
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Beijing, 100050, China
| | - Yongming Zhang
- Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, 2 East Yinghua Road, Beijing, 100029, China
- National Center for Respiratory Diseases, Beijing, 100029, China
| | - Shuang-Qing Zhang
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Beijing, 100050, China.
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2
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Nunes LGA, Ma C, Hoffmann FW, Shay AE, Pitts MW, Hoffmann PR. Selenoprotein I is indispensable for ether lipid homeostasis and proper myelination. J Biol Chem 2024; 300:107259. [PMID: 38582453 PMCID: PMC11061234 DOI: 10.1016/j.jbc.2024.107259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/08/2024] Open
Abstract
Selenoprotein I (SELENOI) catalyzes the final reaction of the CDP-ethanolamine branch of the Kennedy pathway, generating the phospholipids phosphatidylethanolamine (PE) and plasmenyl-PE. Plasmenyl-PE is a key component of myelin and is characterized by a vinyl ether bond that preferentially reacts with oxidants, thus serves as a sacrificial antioxidant. In humans, multiple loss-of-function mutations in genes affecting plasmenyl-PE metabolism have been implicated in hereditary spastic paraplegia, including SELENOI. Herein, we developed a mouse model of nervous system-restricted SELENOI deficiency that circumvents embryonic lethality caused by constitutive deletion and recapitulates phenotypic features of hereditary spastic paraplegia. Resulting mice exhibited pronounced alterations in brain lipid composition, which coincided with motor deficits and neuropathology including hypomyelination, elevated reactive gliosis, and microcephaly. Further studies revealed increased lipid peroxidation in oligodendrocyte lineage cells and disrupted oligodendrocyte maturation both in vivo and in vitro. Altogether, these findings detail a critical role for SELENOI-derived plasmenyl-PE in myelination that is of paramount importance for neurodevelopment.
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Affiliation(s)
- Lance G A Nunes
- Department of Anatomy, Biochemistry, and Physiology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Chi Ma
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - FuKun W Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Ashley E Shay
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Matthew W Pitts
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA.
| | - Peter R Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
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3
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Schweizer U, Wirth EK, Klopstock T, Hölter SM, Becker L, Moskovitz J, Grune T, Fuchs H, Gailus-Durner V, Hrabe de Angelis M, Köhrle J, Schomburg L. Seizures, ataxia and parvalbumin-expressing interneurons respond to selenium supply in Selenop-deficient mice. Redox Biol 2022; 57:102490. [PMID: 36182809 PMCID: PMC9526222 DOI: 10.1016/j.redox.2022.102490] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 11/20/2022] Open
Abstract
Mice with constitutive disruption of the Selenop gene have been key to delineate the importance of selenoproteins in neurobiology. However, the phenotype of this mouse model is exquisitely dependent on selenium supply and timing of selenium supplementation. Combining biochemical, histological, and behavioral methods, we tested the hypothesis that parvalbumin-expressing interneurons in the primary somatosensory cortex and hippocampus depend on dietary selenium availability in Selenop-/- mice. Selenop-deficient mice kept on adequate selenium diet (0.15 mg/kg, i.e. the recommended dietary allowance, RDA) developed ataxia, tremor, and hyperexcitability between the age of 4-5 weeks. Video-electroencephalography demonstrated epileptic seizures in Selenop-/- mice fed the RDA diet, while Selenop± heterozygous mice behaved normally. Both neurological phenotypes, hyperexcitability/seizures and ataxia/dystonia were successfully prevented by selenium supplementation from birth or transgenic expression of human SELENOP under a hepatocyte-specific promoter. Selenium supplementation with 10 μM selenite in the drinking water on top of the RDA diet increased the activity of glutathione peroxidase in the brains of Selenop-/- mice to control levels. The effects of selenium supplementation on the neurological phenotypes were dose- and time-dependent. Selenium supplementation after weaning was apparently too late to prevent ataxia/dystonia, while selenium withdrawal from rescued Selenop-/- mice eventually resulted in ataxia. We conclude that SELENOP expression is essential for preserving interneuron survival under limiting Se supply, while SELENOP appears dispensable under sufficiently high Se status.
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Affiliation(s)
- Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Uniklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany.
| | - Eva K Wirth
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas Klopstock
- Friedrich-Baur-Institute, Department of Neurology, University Hospital, Ludwig Maximilian University of Munich, Ziemssenstraße 1a, 80336, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Sabine M Hölter
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Lore Becker
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Jackob Moskovitz
- Department of Pharmacology & Toxicology, University of Kansas, Lawrence, KS, USA
| | - Tilman Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558, Nuthetal, Germany; German Center for Cardiovascular Research (DZHK), 10117, Berlin, Germany; Department of Physiological Chemistry, Faculty of Chemistry, University of Vienna, 1090, Vienna, Austria; German Center for Diabetes Research (DZD), Ingolstaedter Landstraße. 1, 85764, Neuherberg, Germany
| | - Helmut Fuchs
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Valerie Gailus-Durner
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Martin Hrabe de Angelis
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; Experimental Genetics, TUM School of Life Sciences, Technische Universität München, Alte Akademie 8, 85354, Freising, Germany; German Center for Diabetes Research (DZD), Ingolstaedter Landstraße. 1, 85764, Neuherberg, Germany
| | - Josef Köhrle
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Lutz Schomburg
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
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4
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Schweizer U, Fabiano M. Selenoproteins in brain development and function. Free Radic Biol Med 2022; 190:105-115. [PMID: 35961466 DOI: 10.1016/j.freeradbiomed.2022.07.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/21/2022] [Accepted: 07/26/2022] [Indexed: 01/18/2023]
Abstract
Expression of selenoproteins is widespread in neurons of the central nervous system. There is continuous evidence presented over decades that low levels of selenium or selenoproteins are linked to seizures and epilepsy indicating a failure of the inhibitory system. Many developmental processes in the brain depend on the thyroid hormone T3. T3 levels can be locally increased by the action of iodothyronine deiodinases on the prohormone T4. Since deiodinases are selenoproteins, it is expected that selenoprotein deficiency may affect development of the central nervous system. Studies in genetically modified mice or clinical observations of patients with rare diseases point to a role of selenoproteins in brain development and degeneration. In particular selenoprotein P is central to brain function by virtue of its selenium transport function into and within the brain. We summarize which selenoproteins are essential for the brain, which processes depend on selenoproteins, and what is known about genetic deficiencies of selenoproteins in humans. This review is not intended to cover the potential influence of selenium or selenoproteins on major neurodegenerative disorders in human.
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Affiliation(s)
- Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 11, 53115, Bonn, Germany.
| | - Marietta Fabiano
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 11, 53115, Bonn, Germany
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5
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Liu PH, Chuang GT, Hsiung CN, Yang WS, Ku HC, Lin YC, Chen YS, Huang YY, Lin CH, Li WY, Lin JW, Hsu CN, Hwang JJ, Liao KCW, Hsieh ML, Lee HL, Shen CY, Chang YC. A genome-wide association study for melatonin secretion. Sci Rep 2022; 12:8025. [PMID: 35577822 PMCID: PMC9110427 DOI: 10.1038/s41598-022-12084-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 05/04/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractMelatonin exerts a wide range of effects among various tissues and organs. However, there is currently no study to investigate the genetic determinants of melatonin secretion. Here, we conducted a genome-wide association study (GWAS) for melatonin secretion using morning urine 6-hydroxymelatonin sulfate-to-creatinine ratio (UMCR). We initially enrolled 5000 participants from Taiwan Biobank in this study. After excluding individuals that did not have their urine collected in the morning, those who had history of neurological or psychiatric disorder, and those who failed to pass quality control, association of single nucleotide polymorphisms with log-transformed UMCR adjusted for age, sex and principal components of ancestry were analyzed. A second model additionally adjusted for estimated glomerular filtration rate (eGFR). A total of 2373 participants underwent the genome-wide analysis. Five candidate loci associated with log UMCR (P value ranging from 6.83 × 10−7 to 3.44 × 10−6) encompassing ZFHX3, GALNT15, GALNT13, LDLRAD3 and intergenic between SEPP1 and FLJ32255 were identified. Similar results were yielded with further adjustment for eGFR. Interestingly, the identified genes are associated with circadian behavior, neuronal differentiation, motor disorders, anxiety, and neurodegenerative diseases. We conducted the first GWAS for melatonin secretion and identified five candidate genetic loci associated with melatonin level. Replication and functional studies are needed in the future.
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Handy DE, Joseph J, Loscalzo J. Selenium, a Micronutrient That Modulates Cardiovascular Health via Redox Enzymology. Nutrients 2021; 13:nu13093238. [PMID: 34579115 PMCID: PMC8471878 DOI: 10.3390/nu13093238] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 11/17/2022] Open
Abstract
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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Affiliation(s)
- Diane E. Handy
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA 02115, USA; (J.J.); (J.L.)
- Correspondence: ; Tel.: +1-617-525-4845
| | - Jacob Joseph
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA 02115, USA; (J.J.); (J.L.)
- Department of Medicine, VA Boston Healthcare System, Boston, MA 02115, USA
| | - Joseph Loscalzo
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA 02115, USA; (J.J.); (J.L.)
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7
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Li K, Feng T, Liu L, Liu H, Huang K, Zhou J. Hepatic Proteomic Analysis of Selenoprotein T Knockout Mice by TMT: Implications for the Role of Selenoprotein T in Glucose and Lipid Metabolism. Int J Mol Sci 2021; 22:ijms22168515. [PMID: 34445217 PMCID: PMC8395235 DOI: 10.3390/ijms22168515] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/01/2021] [Accepted: 08/04/2021] [Indexed: 12/14/2022] Open
Abstract
Selenoprotein T (SELENOT, SelT), a thioredoxin-like enzyme, exerts an essential oxidoreductase activity in the endoplasmic reticulum. However, its precise function remains unknown. To gain more understanding of SELENOT function, a conventional global Selenot knockout (KO) mouse model was constructed for the first time using the CRISPR/Cas9 technique. Deletion of SELENOT caused male sterility, reduced size/body weight, lower fed and/or fasting blood glucose levels and lower fasting serum insulin levels, and improved blood lipid profile. Tandem mass tag (TMT) proteomics analysis was conducted to explore the differentially expressed proteins (DEPs) in the liver of male mice, revealing 60 up-regulated and 94 down-regulated DEPs in KO mice. The proteomic results were validated by western blot of three selected DEPs. The elevated expression of Glycogen [starch] synthase, liver (Gys2) is consistent with the hypoglycemic phenotype in KO mice. Furthermore, the bioinformatics analysis showed that Selenot-KO-induced DEPs were mainly related to lipid metabolism, cancer, peroxisome proliferator-activated receptor (PPAR) signaling pathway, complement and coagulation cascades, and protein digestion and absorption. Overall, these findings provide a holistic perspective into SELENOT function and novel insights into the role of SELENOT in glucose and lipid metabolism, and thus, enhance our understanding of SELENOT function.
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Affiliation(s)
- Ke Li
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China; (K.L.); (T.F.); (L.L.); (H.L.); (K.H.)
| | - Tiejun Feng
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China; (K.L.); (T.F.); (L.L.); (H.L.); (K.H.)
| | - Leyan Liu
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China; (K.L.); (T.F.); (L.L.); (H.L.); (K.H.)
| | - Hongmei Liu
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China; (K.L.); (T.F.); (L.L.); (H.L.); (K.H.)
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen 518057, China
| | - Kaixun Huang
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China; (K.L.); (T.F.); (L.L.); (H.L.); (K.H.)
| | - Jun Zhou
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China; (K.L.); (T.F.); (L.L.); (H.L.); (K.H.)
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen 518057, China
- Correspondence:
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Watanabe LM, Hashimoto AC, Torres DJ, Alfulaij N, Peres R, Sultana R, Maunakea AK, Berry MJ, Seale LA. Effect of statin treatment in obese selenium-supplemented mice lacking selenocysteine lyase. Mol Cell Endocrinol 2021; 533:111335. [PMID: 34052303 PMCID: PMC8263501 DOI: 10.1016/j.mce.2021.111335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/14/2021] [Accepted: 05/24/2021] [Indexed: 12/17/2022]
Abstract
People with obesity are often dyslipidemic and prescribed statins to prevent cardiovascular events. A common side effect of statin use is myopathy. This could potentially be caused by the reduction of selenoproteins that curb oxidative stress, in turn, affecting creatine metabolism. We determined if statins regulate hepatic and muscular selenoprotein expression, oxidative stress and creatine metabolism. Mice lacking selenocysteine lyase (Scly KO), a selenium-provider enzyme for selenoprotein synthesis, were fed a high-fat, Se-supplemented diet and treated with simvastatin. Statin improved creatine metabolism in females and oxidative responses in both sexes. Male Scly KO mice were heavier than females after statin treatment. Hepatic selenoproteins were unaffected by statin and genotype in females. Statin upregulated muscular Gpx1 in females but not males, while Scly loss downregulated muscular Gpx1 in males and Selenon in females. Osgin1 was reduced in statin-treated Scly KO males after AmpliSeq analysis. These results refine our understanding of the sex-dependent role of selenium in statin responses.
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Affiliation(s)
- Ligia M Watanabe
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, 96813, USA; Department of Internal Medicine, Faculty of Medicine of Ribeirão Preto, University of São Paulo - FMRP/USP, Brazil
| | - Ann C Hashimoto
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, 96813, USA
| | - Daniel J Torres
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, 96813, USA; Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, HI, 96822, USA
| | - Naghum Alfulaij
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, 96813, USA; Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, HI, 96822, USA
| | - Rafael Peres
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, 96813, USA
| | - Razvan Sultana
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, 96813, USA
| | - Alika K Maunakea
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, 96813, USA
| | - Marla J Berry
- Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, HI, 96822, USA
| | - Lucia A Seale
- Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, HI, 96822, USA.
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Saito Y. Selenium Transport Mechanism via Selenoprotein P-Its Physiological Role and Related Diseases. Front Nutr 2021; 8:685517. [PMID: 34124127 PMCID: PMC8193087 DOI: 10.3389/fnut.2021.685517] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/07/2021] [Indexed: 02/05/2023] Open
Abstract
Selenoprotein P (SELENOP) is selenium (Se)-containing protein in plasma, which is primarily produced in the liver. The “P” in SELENOP originated from the presence in plasma. SELENOP contains selenocysteine, a cysteine analog containing Se instead of sulfur. SELENOP is a multi-functional protein to reduce phospholipid hydroperoxides and to deliver Se from the liver to other tissues, such as those of the brain and testis, playing a pivotal role in Se metabolism and antioxidative defense. Decrease in SELENOP causes various dysfunctions related to Se deficiency and oxidative stress, while excessive SELENOP causes insulin resistance. This review focuses on the Se transport system of SELENOP, particularly its molecular mechanism and physiological role in Se metabolism. Furthermore, the chemical form of Se and its biological meaning is discussed.
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Affiliation(s)
- Yoshiro Saito
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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10
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Torres DJ, Yorgason JT, Mitchell CC, Hagiwara A, Andres MA, Kurokawa S, Steffensen SC, Bellinger FP. Selenoprotein P Modulates Methamphetamine Enhancement of Vesicular Dopamine Release in Mouse Nucleus Accumbens Via Dopamine D2 Receptors. Front Neurosci 2021; 15:631825. [PMID: 33927588 PMCID: PMC8076559 DOI: 10.3389/fnins.2021.631825] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 03/19/2021] [Indexed: 12/25/2022] Open
Abstract
Dopamine (DA) transmission plays a critical role in processing rewarding and pleasurable stimuli. Increased synaptic DA release in the nucleus accumbens (NAc) is a central component of the physiological effects of drugs of abuse. The essential trace element selenium mitigates methamphetamine-induced neurotoxicity. Selenium can also alter DA production and turnover. However, studies have not directly addressed the role of selenium in DA neurotransmission. Selenoprotein P (SELENOP1) requires selenium for synthesis and transports selenium to the brain, in addition to performing other functions. We investigated whether SELENOP1 directly impacts (1) DA signaling and (2) the dopaminergic response to methamphetamine. We used fast-scan cyclic voltammetry to investigate DA transmission and the response to methamphetamine in NAc slices from C57/BL6J SELENOP1 KO mice. Recordings from SELENOP1 KO mouse slices revealed reduced levels of evoked DA release and slower DA uptake rates. Methamphetamine caused a dramatic increase in vesicular DA release in SELENOP1 KO mice not observed in wild-type controls. This elevated response was attenuated by SELENOP1 application through a selenium-independent mechanism involving SELENOP1-apolipoprotein E receptor 2 (ApoER2) interaction to promote dopamine D2 receptor (D2R) function. In wild-type mice, increased vesicular DA release in response to methamphetamine was revealed by blocking D2R activation, indicating that the receptor suppresses the methamphetamine-induced vesicular increase. Our data provide evidence of a direct physiological role for SELENOP1 in the dopaminergic response to methamphetamine and suggest a signaling role for the protein in DA transmission.
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Affiliation(s)
- Daniel J Torres
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i at Mânoa, Honolulu, HI, United States.,Pacific Biosciences Research Center, University of Hawai'i at Mânoa, Honolulu, HI, United States
| | - Jordan T Yorgason
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Catherine C Mitchell
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i at Mânoa, Honolulu, HI, United States
| | - Ayaka Hagiwara
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i at Mânoa, Honolulu, HI, United States
| | - Marilou A Andres
- Pacific Biosciences Research Center, University of Hawai'i at Mânoa, Honolulu, HI, United States
| | | | - Scott C Steffensen
- Department of Psychology, Brigham Young University, Provo, UT, United States
| | - Frederick P Bellinger
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i at Mânoa, Honolulu, HI, United States
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11
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The Function of Selenium in Central Nervous System: Lessons from MsrB1 Knockout Mouse Models. Molecules 2021; 26:molecules26051372. [PMID: 33806413 PMCID: PMC7961861 DOI: 10.3390/molecules26051372] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 11/17/2022] Open
Abstract
MsrB1 used to be named selenoprotein R, for it was first identified as a selenocysteine containing protein by searching for the selenocysteine insert sequence (SECIS) in the human genome. Later, it was found that MsrB1 is homologous to PilB in Neisseria gonorrhoeae, which is a methionine sulfoxide reductase (Msr), specifically reducing L-methionine sulfoxide (L-Met-O) in proteins. In humans and mice, four members constitute the Msr family, which are MsrA, MsrB1, MsrB2, and MsrB3. MsrA can reduce free or protein-containing L-Met-O (S), whereas MsrBs can only function on the L-Met-O (R) epimer in proteins. Though there are isomerases existent that could transfer L-Met-O (S) to L-Met-O (R) and vice-versa, the loss of Msr individually results in different phenotypes in mice models. These observations indicate that the function of one Msr cannot be totally complemented by another. Among the mammalian Msrs, MsrB1 is the only selenocysteine-containing protein, and we recently found that loss of MsrB1 perturbs the synaptic plasticity in mice, along with the astrogliosis in their brains. In this review, we summarized the effects resulting from Msr deficiency and the bioactivity of selenium in the central nervous system, especially those that we learned from the MsrB1 knockout mouse model. We hope it will be helpful in better understanding how the trace element selenium participates in the reduction of L-Met-O and becomes involved in neurobiology.
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Solovyev N, Drobyshev E, Blume B, Michalke B. Selenium at the Neural Barriers: A Review. Front Neurosci 2021; 15:630016. [PMID: 33613188 PMCID: PMC7892976 DOI: 10.3389/fnins.2021.630016] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/20/2021] [Indexed: 12/12/2022] Open
Abstract
Selenium (Se) is known to contribute to several vital physiological functions in mammals: antioxidant defense, fertility, thyroid hormone metabolism, and immune response. Growing evidence indicates the crucial role of Se and Se-containing selenoproteins in the brain and brain function. As for the other essential trace elements, dietary Se needs to reach effective concentrations in the central nervous system (CNS) to exert its functions. To do so, Se-species have to cross the blood-brain barrier (BBB) and/or blood-cerebrospinal fluid barrier (BCB) of the choroid plexus. The main interface between the general circulation of the body and the CNS is the BBB. Endothelial cells of brain capillaries forming the so-called tight junctions are the primary anatomic units of the BBB, mainly responsible for barrier function. The current review focuses on Se transport to the brain, primarily including selenoprotein P/low-density lipoprotein receptor-related protein 8 (LRP8, also known as apolipoprotein E receptor-2) dependent pathway, and supplementary transport routes of Se into the brain via low molecular weight Se-species. Additionally, the potential role of Se and selenoproteins in the BBB, BCB, and neurovascular unit (NVU) is discussed. Finally, the perspectives regarding investigating the role of Se and selenoproteins in the gut-brain axis are outlined.
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Affiliation(s)
| | - Evgenii Drobyshev
- Institut für Ernährungswissenschaft, Universität Potsdam, Potsdam, Germany
| | - Bastian Blume
- Research Unit Analytical BioGeoChemistry, Helmholtz Center Munich – German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Bernhard Michalke
- Research Unit Analytical BioGeoChemistry, Helmholtz Center Munich – German Research Center for Environmental Health (GmbH), Neuherberg, Germany
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13
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Solovyev N. Selenoprotein P and its potential role in Alzheimer's disease. Hormones (Athens) 2020; 19:73-79. [PMID: 31250406 DOI: 10.1007/s42000-019-00112-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/29/2019] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease associated with cognitive decline, loss of memory, and progressive cerebral atrophy. The trace element selenium (Se) is known to be involved in brain pathology. Selenoprotein P (SELENOP), as the main Se transport protein, is, to a great extent, responsible for maintaining Se homeostasis and the hierarchy of selenoprotein expression in the body. Adequate Se supply through SELENOP is vital for proper brain development and function. Additionally, SELENOP may be implicated in pathological processes in the central nervous system, including those in AD. The current review summarizes recent findings on the possible role of SELENOP in AD, with a focus on probable mechanisms: Se delivery to neurons, antioxidant activity, cytoskeleton assembly, interaction with redox-active metals (e.g., copper and iron), and misfolded proteins (amyloid beta and tau protein). The use of SELENOP as a biomarker of Se status is also briefly discussed. Epidemiological studies on Se supplementation are beyond the scope of the current review.
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Affiliation(s)
- Nikolay Solovyev
- Institute of Chemistry, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg, Russian Federation, 199034.
- Department of Chemistry, Atomic & Mass Spectrometry - A&MS Research Unit, Ghent University, Campus Sterre, Krijgslaan, 281-S12, 9000, Ghent, Belgium.
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Leonardi A, Evke S, Lee M, Melendez JA, Begley TJ. Epitranscriptomic systems regulate the translation of reactive oxygen species detoxifying and disease linked selenoproteins. Free Radic Biol Med 2019; 143:573-593. [PMID: 31476365 PMCID: PMC7650020 DOI: 10.1016/j.freeradbiomed.2019.08.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/28/2019] [Accepted: 08/29/2019] [Indexed: 02/07/2023]
Abstract
Here we highlight the role of epitranscriptomic systems in post-transcriptional regulation, with a specific focus on RNA modifying writers required for the incorporation of the 21st amino acid selenocysteine during translation, and the pathologies linked to epitranscriptomic and selenoprotein defects. Epitranscriptomic marks in the form of enzyme-catalyzed modifications to RNA have been shown to be important signals regulating translation, with defects linked to altered development, intellectual impairment, and cancer. Modifications to rRNA, mRNA and tRNA can affect their structure and function, while the levels of these dynamic tRNA-specific epitranscriptomic marks are stress-regulated to control translation. The tRNA for selenocysteine contains five distinct epitranscriptomic marks and the ALKBH8 writer for the wobble uridine (U) has been shown to be vital for the translation of the glutathione peroxidase (GPX) and thioredoxin reductase (TRXR) family of selenoproteins. The reactive oxygen species (ROS) detoxifying selenocysteine containing proteins are a prime examples of how specialized translation can be regulated by specific tRNA modifications working in conjunction with distinct codon usage patterns, RNA binding proteins and specific 3' untranslated region (UTR) signals. We highlight the important role of selenoproteins in detoxifying ROS and provide details on how epitranscriptomic marks and selenoproteins can play key roles in and maintaining mitochondrial function and preventing disease.
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Affiliation(s)
- Andrea Leonardi
- Colleges of Nanoscale Science and Engineering, University at Albany, State University of New York, Albany, NY, USA
| | - Sara Evke
- Colleges of Nanoscale Science and Engineering, State University of New York Polytechnic Institute, Albany, NY, USA
| | - May Lee
- Colleges of Nanoscale Science and Engineering, State University of New York Polytechnic Institute, Albany, NY, USA
| | - J Andres Melendez
- Colleges of Nanoscale Science and Engineering, State University of New York Polytechnic Institute, Albany, NY, USA.
| | - Thomas J Begley
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, USA; RNA Institute, University at Albany, State University of New York, Albany, NY, USA.
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Ha HY, Alfulaij N, Berry MJ, Seale LA. From Selenium Absorption to Selenoprotein Degradation. Biol Trace Elem Res 2019; 192:26-37. [PMID: 31222623 PMCID: PMC6801053 DOI: 10.1007/s12011-019-01771-x] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 06/03/2019] [Indexed: 12/14/2022]
Abstract
Selenium is an essential dietary micronutrient. Ingested selenium is absorbed by the intestines and transported to the liver where it is mostly metabolized to selenocysteine (Sec). Sec is then incorporated into selenoproteins, including selenoprotein P (SELENOP), which is secreted into plasma and serves as a source of selenium to other tissues of the body. Herein, we provide an overview of the biology of selenium from its absorption and distribution to selenoprotein uptake and degradation, with a particular focus on the latter. Molecular mechanisms of selenoprotein degradation include the lysosome-mediated pathway for SELENOP and endoplasmic reticulum-mediated degradation of selenoproteins via ubiquitin-activated proteasomal pathways. Ubiquitin-activated pathways targeting full-length selenoproteins include the peroxisome proliferator-activated receptor gamma-dependent pathway and substrate-dependent ubiquitination. An alternate mechanism is utilized for truncated selenoproteins, in which cullin-RING E3 ubiquitin ligase 2 targets the defective proteins for ubiquitin-proteasomal degradation. Selenoproteins, particularly SELENOP, may have their Sec residues reutilized for new selenoprotein synthesis via Sec decomposition. This review will explore these aspects in selenium biology, providing insights to knowledge gaps that remain to be uncovered.
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Affiliation(s)
- Herena Y Ha
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, HI, 96813, USA
| | - Naghum Alfulaij
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, HI, 96813, USA
| | - Marla J Berry
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, HI, 96813, USA
| | - Lucia A Seale
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, HI, 96813, USA.
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Loss of MsrB1 perturbs spatial learning and long-term potentiation/long-term depression in mice. Neurobiol Learn Mem 2019; 166:107104. [PMID: 31672630 DOI: 10.1016/j.nlm.2019.107104] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/21/2019] [Accepted: 10/27/2019] [Indexed: 12/22/2022]
Abstract
MsrB1 belongs to the methionine sulfoxide reductase family, it is also known as selenoprotein R for the sake of possessing a selenocysteine residue. It has been reported that MsrB1 could interact with actin, TRPM6, clusterin, and amyloid-beta in vitro. Thus, we presumed that MsrB1 may play an important role in central nervous system. To examine whether MsrB1 knockout has any effects on brain development or learning behavior, we carried out histological study on brains of MsrB1 deficient mice, and further tested spatial learning ability and long-term synaptic plasticity of these mice by using Morris water maze and electrophysiological methods. It was observed that loss of MsrB1 did not perturb the overall development of central nervous system except for the astrogliosis in hippocampus, however, it led mice to be incapable in spatial learning and severe impairments in LTP/LTD expression in CA1 of brain slices, along with the down-regulation of the synaptic proteins including PSD95, SYP, GluN2A and GluN2B, as well as the dramatic decrease of CaMKIIs phosphorylation at 286(287) compared with wild type mice. Taken together, these results suggest that MsrB1 is essential for mice spatial learning and LTP/LTD induction, and the MsrB1 related redox homeostasis may be involved in regulating the phosphorylation of CaMKIIs.
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H 2S Protects against Cardiac Cell Hypertrophy through Regulation of Selenoproteins. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:6494306. [PMID: 31583042 PMCID: PMC6754967 DOI: 10.1155/2019/6494306] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/25/2019] [Accepted: 08/05/2019] [Indexed: 02/08/2023]
Abstract
Cardiac hypertrophy is defined as the enlargement of the cardiac myocytes, leading to improper nourishment and oxygen supply due to the increased functional demand. This increased stress on the cardiac system commonly leads to myocardial infarction, contributing to 85% of all cardiac-related deaths. Cystathionine gamma-lyase- (CSE-) derived H2S is a novel gasotransmitter and plays a critical role in the preservation of cardiac functions. Selenocysteine lyase (SCLY) has been identified to produce H2Se, the selenium homologue of H2S. Deficiency of selenium is often found in Keshan disease, a congestive cardiomyopathy. The interaction of H2S and H2Se in cardiac cell hypertrophy has not been explored. In this study, cell viability was evaluated with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Oxidative stress and cell size were observed through immunostaining. The expression of genes was determined by real-time PCR and western blot. Here, we demonstrated that incubation of rat cardiac cells (H9C2) with H2O2 lead to increased oxidative stress and cell surface area, which were significantly attenuated by pretreatment of either H2S or H2Se. H2S incubation induced SCLY/H2Se signaling, which next caused higher expressions and activities of selenoproteins, including glutathione peroxidase and thioredoxin reductase. Furthermore, deficiency of CSE inhibited the expressions of SCLY and selenoprotein P in mouse heart tissues. We also found that both H2S and H2Se stimulated Nrf2-targeted downstream genes. These data suggests that H2S protects against cardiac hypertrophy through enhancement of a group of antioxidant proteins.
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Selenocysteine β-Lyase: Biochemistry, Regulation and Physiological Role of the Selenocysteine Decomposition Enzyme. Antioxidants (Basel) 2019; 8:antiox8090357. [PMID: 31480609 PMCID: PMC6770646 DOI: 10.3390/antiox8090357] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 08/23/2019] [Accepted: 08/27/2019] [Indexed: 12/19/2022] Open
Abstract
The enzyme selenocysteine β-lyase (SCLY) was first isolated in 1982 from pig livers, followed by its identification in bacteria. SCLY works as a homodimer, utilizing pyridoxal 5'-phosphate as a cofactor, and catalyzing the specific decomposition of the amino acid selenocysteine into alanine and selenide. The enzyme is thought to deliver its selenide as a substrate for selenophosphate synthetases, which will ultimately be reutilized in selenoprotein synthesis. SCLY subcellular localization is unresolved, as it has been observed both in the cytosol and in the nucleus depending on the technical approach used. The highest SCLY expression and activity in mammals is found in the liver and kidneys. Disruption of the Scly gene in mice led to obesity, hyperinsulinemia, glucose intolerance, and hepatic steatosis, with SCLY being suggested as a participant in the regulation of energy metabolism in a sex-dependent manner. With the physiological role of SCLY still not fully understood, this review attempts to discuss the available literature regarding SCLY in animals and provides avenues for possible future investigation.
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Disruption of Selenium Handling During Puberty Causes Sex-Specific Neurological Impairments in Mice. Antioxidants (Basel) 2019; 8:antiox8040110. [PMID: 31022880 PMCID: PMC6523490 DOI: 10.3390/antiox8040110] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/20/2019] [Accepted: 04/23/2019] [Indexed: 12/14/2022] Open
Abstract
Selenium is an essential trace element linked to normal development and antioxidant defense mechanisms through its incorporation into selenoproteins via the amino acid, selenocysteine (Sec). Male mice lacking both the Se transporter, selenoprotein P (SELENOP), and selenocysteine lyase (Scly), which plays a role in intracellular Se utilization, require Se supplementation for viability and exhibit neuromotor deficits. Previously, we demonstrated that male SELENOP/Scly double knockout (DKO) mice suffer from loss of motor function and audiogenic seizures due to neurodegeneration, both of which are alleviated by prepubescent castration. The current study examined the neuromotor function of female DKO mice using the rotarod and open field test, as well as the effects of dietary Se restriction. Female DKO mice exhibited a milder form of neurological impairment than their male counterparts. This impairment is exacerbated by removal of Se supplementation during puberty. These results indicate there is a critical time frame in which Se supplementation is essential for neurodevelopment. These sex-specific differences may unveil new insights into dietary requirements for this essential nutrient in humans.
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20
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Potter HG, Ashbrook DG, Hager R. Offspring genetic effects on maternal care. Front Neuroendocrinol 2019; 52:195-205. [PMID: 30576700 DOI: 10.1016/j.yfrne.2018.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/08/2018] [Accepted: 12/17/2018] [Indexed: 12/21/2022]
Abstract
Parental care is found widely across animal taxa and is manifest in a range of behaviours from basic provisioning in cockroaches to highly complex behaviours seen in mammals. The evolution of parental care is viewed as the outcome of an evolutionary cost/benefit trade-off between investing in current and future offspring, leading to the selection of traits in offspring that influence parental behaviour. Thus, level and quality of parental care are affected by both parental and offspring genetic differences that directly and indirectly influence parental care behaviour. While significant research effort has gone into understanding how parental genomes affect parental, and mostly maternal, behaviour, few studies have investigated how offspring genomes affect parental care. In this review, we bring together recent findings across different fields focussing on the mechanism and genetics of offspring effects on maternal care in mammals.
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Affiliation(s)
- Harry G Potter
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester M13 9PT, United Kingdom.
| | - David G Ashbrook
- Department of Genetics, Genomics and Informatics, Translational Science Research Building, Room 415, University of Tennessee Health Science Center, 71 S Manassas St, Memphis, TN 38103, United States
| | - Reinmar Hager
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester M13 9PT, United Kingdom
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21
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Seale LA, Ogawa-Wong AN, Berry MJ. SEXUAL DIMORPHISM IN SELENIUM METABOLISM AND SELENOPROTEINS. Free Radic Biol Med 2018; 127:198-205. [PMID: 29572096 PMCID: PMC6150850 DOI: 10.1016/j.freeradbiomed.2018.03.036] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/14/2018] [Accepted: 03/18/2018] [Indexed: 12/20/2022]
Abstract
Sexual dimorphism, the condition in which males and females in a species differ beyond the morphology of sex organs, delineates critical aspects of the biology of higher eukaryotes, including selenium metabolism. While sex differences in selenium biology have been described by several laboratories, delineation of the effects of sex in selenium function and regulation of selenoprotein expression is still in its infancy. This review encompasses the available information on sex-dependent parameters of selenium metabolism, as well as the effects of selenium on sex hormones. Gaps in the current knowledge of selenium and sex are identified and discussed.
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Affiliation(s)
- Lucia A Seale
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA, 96813.
| | - Ashley N Ogawa-Wong
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital - Harvard Medical School, Boston, MA, USA, 02115
| | - Marla J Berry
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA, 96813
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Mercury's neurotoxicity is characterized by its disruption of selenium biochemistry. Biochim Biophys Acta Gen Subj 2018; 1862:2405-2416. [DOI: 10.1016/j.bbagen.2018.05.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/01/2018] [Accepted: 05/04/2018] [Indexed: 01/07/2023]
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Solovyev N, Drobyshev E, Bjørklund G, Dubrovskii Y, Lysiuk R, Rayman MP. Selenium, selenoprotein P, and Alzheimer's disease: is there a link? Free Radic Biol Med 2018; 127:124-133. [PMID: 29481840 DOI: 10.1016/j.freeradbiomed.2018.02.030] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 02/18/2018] [Accepted: 02/22/2018] [Indexed: 12/13/2022]
Abstract
The essential trace element, selenium (Se), is crucial to the brain but it may be potentially neurotoxic, depending on dosage and speciation; Se has been discussed for decades in relation to Alzheimer's disease (AD). Selenoprotein P (SELENOP) is a secreted heparin-binding glycoprotein which serves as the main Se transport protein in mammals. In vivo studies showed that this protein might have additional functions such as a contribution to redox regulation. The current review focuses on recent research on the possible role of SELENOP in AD pathology, based on model and human studies. The review also briefly summarizes results of epidemiological studies on Se supplementation in relation to brain diseases, including PREADViSE, EVA, and AIBL. Although mainly positive effects of Se are assessed in this review, possible detrimental effects of Se supplementation or exposure, including potential neurotoxicity, are also mentioned. In relation to AD, various roles of SELENOP are discussed, i.e. as the means of Se delivery to neurons, as an antioxidant, in cytoskeleton assembly, in interaction with redox-active metals (copper, iron, and mercury) and with misfolded proteins (amyloid-beta and hyperphosphorylated tau-protein).
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Affiliation(s)
- Nikolay Solovyev
- St. Petersburg State University, Institute of Chemistry, St. Petersburg, Russian Federation.
| | - Evgenii Drobyshev
- Universität Potsdam, Institut für Ernährungswissenschaft, Potsdam, Germany
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway.
| | - Yaroslav Dubrovskii
- St. Petersburg State University, Institute of Chemistry, St. Petersburg, Russian Federation
| | - Roman Lysiuk
- Department of Pharmacognosy and Botany, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
| | - Margaret P Rayman
- Department of Nutritional Sciences, University of Surrey, Guildford, UK
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Ralston NV. Effects of soft electrophiles on selenium physiology. Free Radic Biol Med 2018; 127:134-144. [PMID: 30053507 DOI: 10.1016/j.freeradbiomed.2018.07.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 07/18/2018] [Accepted: 07/23/2018] [Indexed: 12/12/2022]
Abstract
This review examines the effects of neurotoxic electrophiles on selenium (Se) metabolism. Selenium-dependent enzymes depend on the unique and elite functions of selenocysteine (Sec), the 21st proteinogenic amino acid, to perform their biochemical roles. Humans possess 25 selenoprotein genes, ~ half of which are enzymes (selenoenzymes) required for preventing, controlling, or reversing oxidative damage, while others participate in regulating calcium metabolism, thyroid hormone status, protein folding, cytoskeletal structure, Sec synthesis and Se transport. While selenoproteins are expressed in tissue dependent distributions and levels in all cells of all vertebrates, they are particularly important in brain development, health, and functions. As the most potent intracellular nucleophile, Sec is subject to binding by mercury (Hg) and other electron poor soft neurotoxic electrophiles. Epidemiological and environmental studies of the effects of exposures to methyl-Hg (CH3Hg+), elemental Hg (Hg°), and/or other metallic/organic neurotoxic soft electrophiles need to consider the concomitant effects of all members of this class of toxicants in relation to the Se status of their study populations. The contributions of individual electrophiles' discrete and cooperative rates of Se sequestration need to be evaluated in relation to tissue Se reserves of the exposed populations to identify sensitive subgroups which may be at accentuated risk due to poor Se status. Additional study is required to examine possibilities of inherited, acquired, or degenerative neurological disorders of Se homeostasis that may influence vulnerability to soft electrophile exposures. Investigations of soft electrophile toxicity will be enhanced by considering the concomitant effects of combined exposures on tissue Se-availability in relation to pathological consequences during fetal development or in relation to etiologies of neurological disorders and neurodegenerative diseases. Since selenoenzymes are molecular "targets" of soft electrophiles, concomitant evaluation of aggregate exposures to these toxicants in relation to dietary Se intakes will assist regulatory agencies in their goals of improving and protecting public health.
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Affiliation(s)
- Nicholas Vc Ralston
- Earth System Science and Policy, University of North Dakota, Grand Forks, ND, USA.
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25
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Seale LA, Ha HY, Hashimoto AC, Berry MJ. Relationship between selenoprotein P and selenocysteine lyase: Insights into selenium metabolism. Free Radic Biol Med 2018; 127:182-189. [PMID: 29567390 PMCID: PMC6148438 DOI: 10.1016/j.freeradbiomed.2018.03.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/14/2018] [Accepted: 03/18/2018] [Indexed: 10/17/2022]
Abstract
Selenoprotein P (SelenoP) functions as a plasma transporter of selenium (Se) from liver to other tissues via incorporation into multiple selenocysteine (Sec) residues. Selenocysteine lyase (Scly) is an intracellular enzyme that decomposes Sec into selenide, providing Se for the synthesis of new selenoproteins. Both SelenoP and Scly are mostly produced by the liver. Previous studies demonstrated that male mice lacking SelenoP (SelenoP KO) or Scly (Scly KO) had increased or decreased total hepatic Se, respectively. While SelenoP regulation by Se is well-studied, Scly regulation by Se has not been reported. We hypothesize that Scly is negatively regulated by Se levels, and that absence of SelenoP jeopardizes Scly-dependent Se recycling. Using in vitro and in vivo models, we unveiled a tissue-specific Se regulation of Scly gene expression. We also determined that SelenoP, a considered source of intracellular Se, affects Scly expression and activity in vitro but not in vivo, as in the absence of SelenoP, Scly levels and activity remain normal. We also showed that absence of SelenoP does not increase levels of transsulfuration pathway enzymes, which would result in available selenocompounds being decomposed by the actions of cystathionine γ-lyase (CGL or CTH) and cystathionine β-synthase (CBS). Instead, it affects levels of thioredoxin reductase 1 (Txnrd1), an enzyme that can reduce selenite to selenide to be used in selenoprotein production. This study evaluates a potential interplay between SelenoP and Scly, providing further insights into the regulation of selenium metabolism.
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Affiliation(s)
- Lucia A Seale
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, United States.
| | - Herena Y Ha
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, United States
| | - Ann C Hashimoto
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, United States
| | - Marla J Berry
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, United States
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Ashbrook DG, Sharmin N, Hager R. Offspring genes indirectly influence sibling and maternal behavioural strategies over resource share. Proc Biol Sci 2018; 284:rspb.2017.1059. [PMID: 28954905 PMCID: PMC5627198 DOI: 10.1098/rspb.2017.1059] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 08/30/2017] [Indexed: 01/02/2023] Open
Abstract
Family members show behavioural strategies predicted to maximize individual fitness. These behaviours depend directly on genes expressed in focal individuals but also indirectly on genes expressed in other family members. However, how sibling and parental behavioural strategies are modified by genes expressed in family members, and to what degree, remains unclear. To answer this question, we have used a split litter design in an experimental population of genetically variable mouse families, and identified loci that indirectly affected sibling and maternal behaviour simultaneously. These loci map to genomic regions that also show a direct effect on offspring behaviour. Directly and indirectly affected traits were significantly correlated at the phenotypic level, illustrating how indirect effects are caused. Genetic variants in offspring that influence solicitation also impacted their siblings' and maternal behaviour. However, in contrast to predictions from sibling competition, unrelated litter mates benefited from increased solicitation. Overall, such indirect genetic effects explained a large proportion of variation seen in behaviours, with candidate genes involved in metabolism to neuronal development. These results reveal that we need to view behavioural strategies as the result of conjoint selection on genetic variation in all interacting family members.
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Affiliation(s)
- David G Ashbrook
- School of Biological Sciences, Faculty of Biology, Medicine and Health Sciences, University of Manchester, Manchester M13 9PT, UK .,Department of Biological Sciences, University of Toronto, Scarborough, Ontario, Canada
| | - Naorin Sharmin
- School of Biological Sciences, Faculty of Biology, Medicine and Health Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Reinmar Hager
- School of Biological Sciences, Faculty of Biology, Medicine and Health Sciences, University of Manchester, Manchester M13 9PT, UK
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Sexual Dimorphism in the Selenocysteine Lyase Knockout Mouse. Nutrients 2018; 10:nu10020159. [PMID: 29385050 PMCID: PMC5852735 DOI: 10.3390/nu10020159] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 01/19/2018] [Accepted: 01/29/2018] [Indexed: 12/31/2022] Open
Abstract
Selenium (Se) is an essential micronutrient known for its antioxidant properties and health benefits, attributed to its presence in selenoproteins as the amino acid, selenocysteine. Selenocysteine lyase (Scly) catalyzes hydrolysis of selenocysteine to selenide and alanine, facilitating re-utilization of Se for de novo selenoprotein synthesis. Previously, it was reported that male Scly−/− mice develop increased body weight and body fat composition, and altered lipid and carbohydrate metabolism, compared to wild type mice. Strikingly, females appeared to present with a less severe phenotype, suggesting the relationship between Scly and energy metabolism may be regulated in a sex-specific manner. Here, we report that while body weight and body fat gain occur in both male and female Scly−/− mice, strikingly, males are susceptible to developing glucose intolerance, whereas female Scly−/− mice are protected. Because Se is critical for male reproduction, we hypothesized that castration would attenuate the metabolic dysfunction observed in male Scly−/− mice by eliminating sequestration of Se in testes. We report that fasting serum insulin levels were significantly reduced in castrated males compared to controls, but islet area was unchanged between groups. Finally, both male and female Scly−/− mice exhibit reduced hypothalamic expression of selenoproteins S, M, and glutathione peroxidase 1.
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Shetty S, Marsicano JR, Copeland PR. Uptake and Utilization of Selenium from Selenoprotein P. Biol Trace Elem Res 2018; 181:54-61. [PMID: 28488249 PMCID: PMC5680150 DOI: 10.1007/s12011-017-1044-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 05/01/2017] [Indexed: 11/25/2022]
Abstract
Selenoprotein P (SELENOP) is a serum glycoprotein that is required for proper selenium distribution in mammals, particularly in supplying selenium to the brain and testes. As the sole mechanism for providing essential selenium to developing spermatozoa, SELENOP metabolism is central to male fertility in all mammals. In addition, this process is important for proper brain function, especially under conditions of limited dietary selenium. Several specific and nonspecific mechanisms for SELENOP uptake in target tissues have been described, but the utilization of SELENOP as a source of selenium for intracellular selenoprotein production has not been systematically characterized. In this report, we examine the process of SELENOP uptake using a robust selenium uptake assay that measures selenium utilization in cells fed 75Se-SELENOP. Using a series of inhibitors and modulators we have identified specific regulators of the process and found that SELENOP must be in an oxidized state for uptake. This assay also demonstrates that SELENOP uptake is not highly sequence specific as the zebrafish protein is recognized and processed by mammalian cells.
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Affiliation(s)
- Sumangala Shetty
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ, 08854, USA
| | - John R Marsicano
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ, 08854, USA
| | - Paul R Copeland
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ, 08854, USA.
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Chemical Speciation of Selenium and Mercury as Determinant of Their Neurotoxicity. ADVANCES IN NEUROBIOLOGY 2017; 18:53-83. [PMID: 28889263 DOI: 10.1007/978-3-319-60189-2_4] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The antagonism of mercury toxicity by selenium has been well documented. Mercury is a toxic metal, widespread in the environment. The main target organs (kidneys, lungs, or brain) of mercury vary depending on its chemical forms (inorganic or organic). Selenium is a semimetal essential to mammalian life as part of the amino acid selenocysteine, which is required to the synthesis of the selenoproteins. This chapter has the aim of disclosing the role of selenide or hydrogen selenide (Se-2 or HSe-) as central metabolite of selenium and as an important antidote of the electrophilic mercury forms (particularly, Hg2+ and MeHg). Emphasis will be centered on the neurotoxicity of electrophile forms of mercury and selenium. The controversial participation of electrophile mercury and selenium forms in the development of some neurodegenerative disease will be briefly presented. The potential pharmacological use of organoseleno compounds (Ebselen and diphenyl diselenide) in the treatment of mercury poisoning will be considered. The central role of thiol (-SH) and selenol (-SeH) groups as the generic targets of electrophile mercury forms and the need of new in silico tools to guide the future biological researches will be commented.
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Competition between the Brain and Testes under Selenium-Compromised Conditions: Insight into Sex Differences in Selenium Metabolism and Risk of Neurodevelopmental Disease. J Neurosci 2016; 35:15326-38. [PMID: 26586820 DOI: 10.1523/jneurosci.2724-15.2015] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Selenium (Se) is essential for both brain development and male fertility. Male mice lacking two key genes involved in Se metabolism (Scly(-/-)Sepp1(-/-) mice), selenoprotein P (Sepp1) and Sec lyase (Scly), develop severe neurological dysfunction, neurodegeneration, and audiogenic seizures that manifest beginning in early adulthood. We demonstrate that prepubescent castration of Scly(-/-)Sepp1(-/-) mice prevents behavioral deficits, attenuates neurodegeneration, rescues maturation of GABAergic inhibition, and increases brain selenoprotein levels. Moreover, castration also yields similar neuroprotective benefits to Sepp1(-/-) and wild-type mice challenged with Se-deficient diets. Our data show that, under Se-compromised conditions, the brain and testes compete for Se utilization, with concomitant effects on neurodevelopment and neurodegeneration. SIGNIFICANCE STATEMENT Selenium is an essential trace element that promotes male fertility and brain function. Herein, we report that prepubescent castration provides neuroprotection by increasing selenium-dependent antioxidant activity in the brain, revealing a competition between the brain and testes for selenium utilization. These findings provide novel insight into the interaction of sex and oxidative stress upon the developing brain and have potentially significant implications for the prevention of neurodevelopmental disorders characterized by aberrant excitatory/inhibitory balance, such as schizophrenia and epilepsy.
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Seale LA, Gilman CL, Hashimoto AC, Ogawa-Wong AN, Berry MJ. Diet-induced obesity in the selenocysteine lyase knockout mouse. Antioxid Redox Signal 2015; 23:761-74. [PMID: 26192035 PMCID: PMC4589310 DOI: 10.1089/ars.2015.6277] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIMS Selenocysteine lyase (Scly) mediates selenocysteine decomposition. It was previously demonstrated that, upon adequate caloric intake (12% kcal fat) and selenium deficiency, disruption of Scly in mice leads to development of metabolic syndrome. In this study, we investigate the effect of a high-fat (45% kcal) selenium-adequate diet in Scly knockout (KO) mice on development of metabolic syndrome. Involvement of selenoproteins in energy metabolism after Scly disruption was also examined in vitro in the murine hepatoma cell line, Hepa1-6, following palmitate treatment. RESULTS Scly KO mice were more susceptible to diet-induced obesity than their wild-type counterparts after feeding a high-fat selenium-adequate diet. Scly KO mice had aggravated hyperinsulinemia, hypercholesterolemia, glucose, and insulin intolerance, but unchanged inflammatory cytokines and expression of most selenoproteins, except increased serum selenoprotein P (Sepp1). Scly KO mice also exhibited enhanced hepatic levels of pyruvate and enzymes involved in the regulation of pyruvate cycling, such as pyruvate carboxylase (Pcx) and pyruvate dehydrogenase (Pdh). However, in vitro silencing of Scly in Hepa1-6 cells led to diminished Sepp1 expression, and concomitant palmitate treatment decreased Pdh expression. INNOVATION The role of selenium in lipid metabolism is recognized, but specific selenium-dependent mechanisms leading to obesity are unclear. This study uncovers that Scly has a remarkable effect on obesity and metabolic syndrome development triggered by high-fat exposure, independent of the expression of most selenoproteins. CONCLUSION Diet-induced obesity in Scly KO mice is aggravated, with effects on pyruvate levels and consequent activation of energy metabolism independent of selenoprotein levels.
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Affiliation(s)
- Lucia A Seale
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa , Honolulu, Hawaii
| | - Christy L Gilman
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa , Honolulu, Hawaii
| | - Ann C Hashimoto
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa , Honolulu, Hawaii
| | - Ashley N Ogawa-Wong
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa , Honolulu, Hawaii
| | - Marla J Berry
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa , Honolulu, Hawaii
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Solovyev ND. Importance of selenium and selenoprotein for brain function: From antioxidant protection to neuronal signalling. J Inorg Biochem 2015; 153:1-12. [PMID: 26398431 DOI: 10.1016/j.jinorgbio.2015.09.003] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 09/03/2015] [Accepted: 09/09/2015] [Indexed: 12/21/2022]
Abstract
Multiple biological functions of selenium manifest themselves mainly via 25 selenoproteins that have selenocysteine at their active centre. Selenium is vital for the brain and seems to participate in the pathology of disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and epilepsy. Since selenium was shown to be involved in diverse functions of the central nervous system, such as motor performance, coordination, memory and cognition, a possible role of selenium and selenoproteins in brain signalling pathways may be assumed. The aim of the present review is to analyse possible relations between selenium and neurotransmission. Selenoproteins seem to be of special importance in the development and functioning of GABAergic (GABA, γ-aminobutyric acid) parvalbumin positive interneurons of the cerebral cortex and hippocampus. Dopamine pathway might be also selenium dependent as selenium shows neuroprotection in the nigrostriatal pathway and also exerts toxicity towards dopaminergic neurons under higher concentrations. Recent findings also point to acetylcholine neurotransmission involvement. The role of selenium and selenoproteins in neurotransmission might not only be limited to their antioxidant properties but also to inflammation, influencing protein phosphorylation and ion channels, alteration of calcium homeostasis and brain cholesterol metabolism. Moreover, a direct signalling function was proposed for selenoprotein P through interaction with post-synaptic apoliprotein E receptors 2 (ApoER2).
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Affiliation(s)
- Nikolay D Solovyev
- Institute of Chemistry, St. Petersburg State University, St. Petersburg 198504, Russian Federation.
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Mahdi Y, Xu XM, Carlson BA, Fradejas N, Günter P, Braun D, Southon E, Tessarollo L, Hatfield DL, Schweizer U. Expression of Selenoproteins Is Maintained in Mice Carrying Mutations in SECp43, the tRNA Selenocysteine 1 Associated Protein (Trnau1ap). PLoS One 2015; 10:e0127349. [PMID: 26043259 PMCID: PMC4456167 DOI: 10.1371/journal.pone.0127349] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 04/14/2015] [Indexed: 12/31/2022] Open
Abstract
Selenocysteine tRNA 1 associated protein (Trnau1ap) has been characterized as a tRNA[Ser]Sec-binding protein of 43 kDa, hence initially named SECp43. Previous studies reported its presence in complexes containing tRNA[Ser]Sec implying a role of SECp43 as a co-factor in selenoprotein expression. We generated two conditionally mutant mouse models targeting exons 3+4 and exons 7+8 eliminating parts of the first RNA recognition motif or of the tyrosine-rich domain, respectively. Constitutive inactivation of exons 3+4 of SECp43 apparently did not affect the mice or selenoprotein expression in several organs. Constitutive deletion of exons 7+8 was embryonic lethal. We therefore generated hepatocyte-specific Secp43 knockout mice and characterized selenoprotein expression in livers of mutant mice. We found no significant changes in the levels of 75Se-labelled hepatic proteins, selenoprotein levels as determined by Western blot analysis, enzymatic activity or selenoprotein mRNA abundance. The methylation pattern of tRNA[Ser]Sec remained unchanged. Truncated Secp43 Δ7,8mRNA increased in Secp43-mutant livers suggesting auto-regulation of Secp43 mRNA abundance. We found no signs of liver damage in Secp433-mutant mice, but neuron-specific deletion of exons 7+8 impaired motor performance, while not affecting cerebral selenoprotein expression or cerebellar development. These findings suggest that the targeted domains in the SECp43 protein are not essential for selenoprotein biosynthesis in hepatocytes and neurons. Whether the remaining second RNA recognition motif plays a role in selenoprotein biosynthesis and which other cellular process depends on SECp43 remains to be determined.
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Affiliation(s)
- Yassin Mahdi
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Xue-Ming Xu
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Bradley A. Carlson
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Noelia Fradejas
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Paul Günter
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Doreen Braun
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Eileen Southon
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lino Tessarollo
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dolph L. Hatfield
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
- * E-mail:
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Cardoso BR, Roberts BR, Bush AI, Hare DJ. Selenium, selenoproteins and neurodegenerative diseases. Metallomics 2015; 7:1213-28. [DOI: 10.1039/c5mt00075k] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A review of selenium's essential role in normal brain function and its potential involvement in neurodegenerative diseases.
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Affiliation(s)
- Bárbara Rita Cardoso
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
- Faculty of Pharmaceutical Sciences
- Department of Food and Experimental Nutrition
| | - Blaine R. Roberts
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
| | - Ashley I. Bush
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
| | - Dominic J. Hare
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
- Elemental Bio-imaging Facility
- University of Technology Sydney
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Pitts MW, Byrns CN, Ogawa-Wong AN, Kremer P, Berry MJ. Selenoproteins in nervous system development and function. Biol Trace Elem Res 2014; 161:231-45. [PMID: 24974905 PMCID: PMC4222985 DOI: 10.1007/s12011-014-0060-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 06/23/2014] [Indexed: 01/03/2023]
Abstract
Selenoproteins are a distinct class of proteins that are characterized by the co-translational incorporation of selenium (Se) in the form of the 21st amino acid selenocysteine. Selenoproteins provide a key defense against oxidative stress, as many of these proteins participate in oxidation-reduction reactions neutralizing reactive oxygen species, where selenocysteine residues act as catalytic sites. Many selenoproteins are highly expressed in the brain, and mouse knockout studies have determined that several are required for normal brain development. In parallel with these laboratory studies, recent reports of rare human cases with mutations in genes involved in selenoprotein biosynthesis have described individuals with an assortment of neurological problems that mirror those detailed in knockout mice. These deficits include impairments in cognition and motor function, seizures, hearing loss, and altered thyroid metabolism. Additionally, due to the fact that oxidative stress is a key feature of neurodegenerative disease, there is considerable interest in the therapeutic potential of selenium supplementation for human neurological disorders. Studies performed in cell culture and rodent models have demonstrated that selenium administration attenuates oxidative stress, prevents neurodegeneration, and counters cell signaling mechanisms known to be dysregulated in certain disease states. However, there is currently no definitive evidence in support of selenium supplementation to prevent and/or treat common neurological conditions in the general population. It appears likely that, in humans, supplementation with selenium may only benefit certain subpopulations, such as those that are either selenium-deficient or possess genetic variants that affect selenium metabolism.
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Affiliation(s)
- Matthew W Pitts
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo St, Honolulu, HI, 96813, USA,
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Yakubov E, Buchfelder M, Eyüpoglu IY, Savaskan NE. Selenium action in neuro-oncology. Biol Trace Elem Res 2014; 161:246-54. [PMID: 25164034 DOI: 10.1007/s12011-014-0111-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 08/18/2014] [Indexed: 12/31/2022]
Abstract
The trace element selenium and selenocysteine-carrying selenoproteins play a pivotal role in the brain. Beside the essential function during development and maintenance of brain action, selenium has also been associated with several neurological and neuro-oncological conditions. Reliable supply of selenium is important since selenium compounds can affect tumor microenvironment and neoangiogenesis in malignant gliomas (WHO grade III and IV [glioblastoma, GBM]) via induction of apoptosis and alteration of matrix metalloproteinases expression. Here, we summarize recent findings focusing on the anti-toxicity and cancer-preventive properties of selenium and their implication in current multimodal therapies including temozolomide (Temodal), cyclophosphamide (Endoxan), and cisplatin (DDP, Platiblastin, and Platinol). We shed light on unintended side effects in chemotherapy and the developments of novel combinatorial chemotherapeutics with selenium compounds. We found that selenium and selenium compounds have dual action profiles with direct anti-cancer and chemotherapy-intensifier effects as well as neuroprotective and cytoprotective agents. Current selenium trials and selenium supplementation with focus on neuro-oncology will be discussed with regard to low-adequate-to-high/toxic selenium status.
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Affiliation(s)
- Eduard Yakubov
- Department of Neurosurgery, Universitätsklinikum Erlangen, FAU-Friedrich-Alexander Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
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Byrns CN, Pitts MW, Gilman CA, Hashimoto AC, Berry MJ. Mice lacking selenoprotein P and selenocysteine lyase exhibit severe neurological dysfunction, neurodegeneration, and audiogenic seizures. J Biol Chem 2014; 289:9662-74. [PMID: 24519931 DOI: 10.1074/jbc.m113.540682] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Selenoproteins are a unique family of proteins, characterized by the co-translational incorporation of selenium as selenocysteine, which play key roles in antioxidant defense. Among selenoproteins, selenoprotein P (Sepp1) is particularly distinctive due to the fact that it contains multiple selenocysteine residues and has been postulated to act in selenium transport. Within the brain, Sepp1 delivers selenium to neurons by binding to the ApoER2 receptor. Upon feeding a selenium-deficient diet, mice lacking ApoER2 or Sepp1 develop severe neurological dysfunction and exhibit widespread brainstem neurodegeneration, indicating an important role for ApoER2-mediated Sepp1 uptake in normal brain function. Selenocysteine lyase (Scly) is an enzyme that plays an important role in selenium homeostasis, in that it catalyzes the decomposition of selenocysteine and allows selenium to be recycled for additional selenoprotein synthesis. We previously reported that constitutive deletion of Scly results in neurological deficits only when mice are challenged with a low selenium diet. To gain insight into the relationship between Sepp1 and Scly in selenium metabolism, we created novel transgenic mice constitutively lacking both genes (Scly(-/-)Sepp1(-/-)) and characterized the neurobehavioral phenotype. We report that deletion of Scly in conjunction with Sepp1 further aggravates the phenotype of Sepp1(-/-) mice, as these mice needed supraphysiological selenium supplementation to survive, and surviving mice exhibited impaired motor coordination, audiogenic seizures, and brainstem neurodegeneration. These findings provide the first in vivo evidence that Scly and Sepp1 work cooperatively to maintain selenoprotein function in the mammalian brain.
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Affiliation(s)
- China N Byrns
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
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Vinceti M, Mandrioli J, Borella P, Michalke B, Tsatsakis A, Finkelstein Y. Selenium neurotoxicity in humans: bridging laboratory and epidemiologic studies. Toxicol Lett 2013; 230:295-303. [PMID: 24269718 DOI: 10.1016/j.toxlet.2013.11.016] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 11/06/2013] [Accepted: 11/14/2013] [Indexed: 12/14/2022]
Abstract
Selenium is a metalloid of considerable interest in the human from both a toxicological and a nutritional perspective, with a very narrow safe range of intake. Acute selenium intoxication is followed by adverse effects on the nervous system with special clinical relevance, while the neurotoxicity of long-term overexposure is less characterized and recognized. We aimed to address this issue from a public health perspective, focusing on both laboratory studies and the few epidemiologic human studies available, with emphasis on their methodological strengths and limitations. The frequently overlooked differences in toxicity and biological activity of selenium compounds are also outlined. In addition to lethargy, dizziness, motor weakness and paresthesias, an excess risk of amyotrophic lateral sclerosis is the effect on the nervous system which has been more consistently associated with chronic low-level selenium overexposure, particularly to its inorganic compounds. Additional research efforts are needed to better elucidate the neurotoxic effects exerted by selenium overexposure.
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Affiliation(s)
- Marco Vinceti
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Department of Diagnostic, Clinical and Public Health Medicine, University of Modena and Reggio Emilia, Modena, Italy; Trace Element Institute for Unesco Satellite Center, Department of Diagnostic, Clinical and Public Health Medicine, University of Modena and Reggio Emilia, Modena, Italy.
| | - Jessica Mandrioli
- Department of Neuroscience, University of Modena and Reggio Emilia and Local Health Unit of Modena, Modena, Italy
| | - Paola Borella
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Department of Diagnostic, Clinical and Public Health Medicine, University of Modena and Reggio Emilia, Modena, Italy; Trace Element Institute for Unesco Satellite Center, Department of Diagnostic, Clinical and Public Health Medicine, University of Modena and Reggio Emilia, Modena, Italy
| | - Bernhard Michalke
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München - German Research Center for Environmental Health GmbH, Munich, Germany
| | - Aristidis Tsatsakis
- Department of Forensic Sciences and Toxicology, University of Crete, Heraklion, Greece
| | - Yoram Finkelstein
- Neurology and Toxicology Service and Unit, Shaare Zedek Medical Center, Jerusalem, Israel
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Raman AV, Pitts MW, Seyedali A, Hashimoto AC, Bellinger FP, Berry MJ. Selenoprotein W expression and regulation in mouse brain and neurons. Brain Behav 2013; 3:562-74. [PMID: 24392277 PMCID: PMC3869984 DOI: 10.1002/brb3.159] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/24/2013] [Accepted: 06/26/2013] [Indexed: 12/03/2022] Open
Abstract
Background Selenoprotein W (Sepw1) is a selenium-containing protein that is abundant in brain and muscle of vertebrate animals. Muscular expression of Sepw1 is reduced by dietary selenium (Se) deficiency in mammals, whereas brain expression is maintained. However, expression of Sepw1 depends on the Se transporter selenoprotein P (Sepp1). Methods We assessed the regional and cellular expression of Sepw1 in the mouse brain and neuronal cultures. Results We found that Sepw1 is widespread in neurons and neuropil of mouse brain and appears in both the soma and processes of neurons in culture. Pyramidal neurons of cortex and hippocampus express high levels of Sepw1. It is also abundant in Purkinje neurons and their dendritic arbors in the cerebellum. Analysis of synaptosome fractions prepared from mice brains indicated that Sepw1 is present at synapses, as were several proteins involved in selenoprotein synthesis. Synaptic expression of Sepw1 expression is reduced in mice lacking Sepp1 compared with control mice, although selenoprotein synthesis factors were similarly expressed in both genotypes. Lastly, Sepw1 mRNA coimmunoprecipitates with Staufen 2 protein in a human neuronal cell line. Conclusions Our results suggest that Sepw1 may be locally synthesized in distal compartments of neurons including synapses.
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Affiliation(s)
- Arjun V Raman
- Cell and Molecular Biology Department John A. Burns School of Medicine, University of Hawai'i at Manoa Honolulu, Hawaii
| | - Matthew W Pitts
- Cell and Molecular Biology Department John A. Burns School of Medicine, University of Hawai'i at Manoa Honolulu, Hawaii
| | - Ali Seyedali
- Cell and Molecular Biology Department John A. Burns School of Medicine, University of Hawai'i at Manoa Honolulu, Hawaii
| | - Ann C Hashimoto
- Cell and Molecular Biology Department John A. Burns School of Medicine, University of Hawai'i at Manoa Honolulu, Hawaii
| | - Frederick P Bellinger
- Cell and Molecular Biology Department John A. Burns School of Medicine, University of Hawai'i at Manoa Honolulu, Hawaii
| | - Marla J Berry
- Cell and Molecular Biology Department John A. Burns School of Medicine, University of Hawai'i at Manoa Honolulu, Hawaii
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Oxidant balance in brain of rats receiving different compounds of selenium. Biometals 2013; 26:763-71. [PMID: 23839117 PMCID: PMC3776242 DOI: 10.1007/s10534-013-9654-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 07/02/2013] [Indexed: 11/09/2022]
Abstract
The influence of two organic selenocompounds and sodium selenite on oxidant processes in rat brain tissue was investigated. The study was performed on male Wistar rats. The animals were divided into four groups: I—control; II—administered with sodium selenite; III—provided with selenoorganic compound A of chain structure 4-(o-tolyl-)-selenosemicarbazide of 2-chlorobenzoic acid and IV—provided with selenoorganic compound B of ring structure 3-(2-chlorobenzoylamino-)-2-(o-tolylimino-)-4-methyl-4-selenazoline. Rats were treated by stomach tube at a dose of 5 × 10−4 mg of selenium/g of b.w. once a day for a period of 10 days. In brain homogenates total antioxidant status (TAS), activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx), concentrations of ascorbic acid (AA) and reduced glutathione (GSH) as well as concentration of malonyl dialdehyde (MDA) were determined. TAS was insignificantly diminished in all selenium-supplemented groups versus control. SOD was not significantly influenced by administration of selenium. GPx was markedly decreased in group III versus control, whereas increased in group IV versus control and group III. Selenosemicarbazide depleted AA in well-marked way versus group II. GSH was significantly depressed in group III versus both control and group II and diminished in group IV versus group II. MDA was significantly decreased in group III versus both control and group II, whereas in group IV increased versus group III. As selenazoline A did not decrease elements of antioxidant barrier and increased GPx activity, it seems to be a promising agent for future studies concerning its possible application as a selenium supplement.
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Vinceti M, Solovyev N, Mandrioli J, Crespi CM, Bonvicini F, Arcolin E, Georgoulopoulou E, Michalke B. Cerebrospinal fluid of newly diagnosed amyotrophic lateral sclerosis patients exhibits abnormal levels of selenium species including elevated selenite. Neurotoxicology 2013; 38:25-32. [PMID: 23732511 DOI: 10.1016/j.neuro.2013.05.016] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 05/17/2013] [Accepted: 05/23/2013] [Indexed: 12/11/2022]
Abstract
Exposure to selenium, and particularly to its inorganic forms, has been hypothesized as a risk factor for amyotrophic lateral sclerosis (ALS), a fast progressing motor neuron disease with poorly understood etiology. However, no information is known about levels of inorganic and some organic selenium species in the central nervous system of ALS patients, and recent observations suggest that peripheral biomarkers of exposure are unable to predict these levels for several Se species including the inorganic forms. Using a hospital-referred case-control series and advanced selenium speciation methods, we compared the chemical species of selenium in cerebrospinal fluid from 38 ALS patients to those of 38 reference neurological patients matched on age and gender. We found that higher concentrations of inorganic selenium in the form of selenite and of human serum albumin-bound selenium were associated with increased ALS risk (relative risks 3.9 (95% confidence interval 1.2-11.0) and 1.7 (1.0-2.9) for 0.1μg/L increase). Conversely, lower concentrations of selenoprotein P-bound selenium were associated with increased risk (relative risk 0.2 for 1μg/L increase, 95% confidence interval 0.04-0.8). The associations were stronger among cases age 50 years or older, who are postulated to have lower rates of genetic disease origin. These results suggest that excess selenite and human serum albumin bound-selenium and low levels of selenoprotein P-bound selenium in the central nervous system, which may be related, may play a role in ALS etiology.
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Affiliation(s)
- Marco Vinceti
- CREAGEN - Environmental, Genetic and Nutritional Epidemiology Research Center, Department of Diagnostic, Clinical and Public Health Medicine, University of Modena and Reggio Emilia, Modena, Italy.
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Steinbrenner H, Sies H. Selenium homeostasis and antioxidant selenoproteins in brain: implications for disorders in the central nervous system. Arch Biochem Biophys 2013; 536:152-7. [PMID: 23500141 DOI: 10.1016/j.abb.2013.02.021] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 02/25/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
Abstract
The essential trace element selenium, as selenocysteine, is incorporated into antioxidant selenoproteins such as glutathione peroxidases (GPx), thioredoxin reductases (TrxR) and selenoprotein P (Sepp1). Although comparatively low in selenium content, the brain exhibits high priority for selenium supply and retention under conditions of dietary selenium deficiency. Liver-derived Sepp1 is the major transport protein in plasma to supply the brain with selenium, serving as a "survival factor" for neurons in culture. Sepp1 expression has also been detected within the brain. Presumably, astrocytes secrete Sepp1, which is subsequently taken up by neurons via the apolipoprotein E receptor 2 (ApoER2). Knock-out of Sepp1 or ApoER2 as well as neuron-specific ablation of selenoprotein biosynthesis results in neurological dysfunction in mice. Astrocytes, generally less vulnerable to oxidative stress than neurons, are capable of up-regulating the expression of antioxidant selenoproteins upon brain injury. Occurrence of neurological disorders has been reported occasionally in patients with inadequate nutritional selenium supply or a mutation in the gene encoding selenocysteine synthase, one of the enzymes involved in selenoprotein biosynthesis. In three large trials carried out among elderly persons, a low selenium status was associated with faster decline in cognitive functions and poor performance in tests assessing coordination and motor speed. Future research is required to better understand the role of selenium and selenoproteins in brain diseases including hepatic encephalopathy.
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Affiliation(s)
- Holger Steinbrenner
- Institute for Biochemistry and Molecular Biology I, Heinrich-Heine-University, Düsseldorf, Germany
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Dewing AS, Rueli RH, Robles MJ, Nguyen-Wu ED, Zeyda T, Berry MJ, Bellinger FP. Expression and regulation of mouse selenoprotein P transcript variants differing in non-coding RNA. RNA Biol 2012; 9:1361-9. [PMID: 23064117 PMCID: PMC3597576 DOI: 10.4161/rna.22290] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Selenoprotein P (Sepp1), a glycoprotein rich in selenium, is thought to function in selenium transport throughout the body. The sepp1 gene locus potentially produces three alternative transcripts that differ only in their 5' untranslated regions (5'UTRs) and not in their protein coding regions, as indicated by transcript information in genomic databases. Here we investigated the distribution, relative expression, and biological significance of these transcript variants. We confirmed the expression of Sepp1 transcript variants using PCR and sequencing. Using 5'-RACE, we identified multiple 5'-termini upstream from three different splice donor sites, and a single splice acceptor site for exon 2. We found regional and temporal changes in variant expression in select adult and neonate murine tissue and brain regions. Distribution of variants in heart and kidney varied with stage of development. Notably, the Sepp1b variant was localized specifically to the hippocampus in brain. Targeted silencing of individual variants using RNAi demonstrated the biological importance for all transcript variants in cell viability. Additionally, we determined that the Sepp1b variant is a specific target for the miR-7 microRNA by means of its unique 5'UTR structure. Our results emphasize the importance of non-coding transcript variations as a regulatory means for Sepp1 expression in different tissues and stages of development. The presence of a variant localized in the hippocampus and regulated by a microRNA may have implications for the known deficits in synaptic function caused by genetic deletion of Sepp1.
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Affiliation(s)
- Andrea S.T. Dewing
- Department of Cell and Molecular Biology; John A. Burns School of Medicine; University of Hawai’I; Honolulu, HI USA
| | - Rachel H. Rueli
- Department of Cell and Molecular Biology; John A. Burns School of Medicine; University of Hawai’I; Honolulu, HI USA
| | - Michael J. Robles
- Department of Cell and Molecular Biology; John A. Burns School of Medicine; University of Hawai’I; Honolulu, HI USA
| | - Elizabeth D. Nguyen-Wu
- Department of Cell and Molecular Biology; John A. Burns School of Medicine; University of Hawai’I; Honolulu, HI USA
| | - Thomas Zeyda
- InGenious Targeting Laboratory; Ronkonkoma, NY USA
| | - Marla J. Berry
- Department of Cell and Molecular Biology; John A. Burns School of Medicine; University of Hawai’I; Honolulu, HI USA
| | - Frederick P. Bellinger
- Department of Cell and Molecular Biology; John A. Burns School of Medicine; University of Hawai’I; Honolulu, HI USA
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Disruption of the selenocysteine lyase-mediated selenium recycling pathway leads to metabolic syndrome in mice. Mol Cell Biol 2012; 32:4141-54. [PMID: 22890841 DOI: 10.1128/mcb.00293-12] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Selenium (Se) is an essential trace element used for biosynthesis of selenoproteins and is acquired either through diet or cellular recycling mechanisms. Selenocysteine lyase (Scly) is the enzyme that supplies Se for selenoprotein biosynthesis via decomposition of the amino acid selenocysteine (Sec). Knockout (KO) of Scly in a mouse affected hepatic glucose and lipid homeostasis. Mice lacking Scly and raised on an Se-adequate diet exhibit hyperinsulinemia, hyperleptinemia, glucose intolerance, and hepatic steatosis, with increased hepatic oxidative stress, but maintain selenoprotein levels and circulating Se status. Insulin challenge of Scly KO mice results in attenuated Akt phosphorylation but does not decrease phosphorylation levels of AMP kinase alpha (AMPKα). Upon dietary Se restriction, Scly KO animals develop several characteristics of metabolic syndrome, such as obesity, fatty liver, and hypercholesterolemia, with aggravated hyperleptinemia, hyperinsulinemia, and glucose intolerance. Hepatic glutathione peroxidase 1 (GPx1) and selenoprotein S (SelS) production and circulating selenoprotein P (Sepp1) levels are significantly diminished. Scly disruption increases the levels of insulin-signaling inhibitor PTP1B. Our results suggest a dependence of glucose and lipid homeostasis on Scly activity. These findings connect Se and energy metabolism and demonstrate for the first time a unique physiological role of Scly in an animal model.
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