1
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Morabbi A, Karimian M. Trace and essential elements as vital components to improve the performance of the male reproductive system: Implications in cell signaling pathways. J Trace Elem Med Biol 2024; 83:127403. [PMID: 38340548 DOI: 10.1016/j.jtemb.2024.127403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/02/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024]
Abstract
Successful male fertilization requires the main processes such as normal spermatogenesis, sperm capacitation, hyperactivation, and acrosome reaction. The progress of these processes depends on some endogenous and exogenous factors. So, the optimal level of ions and essential and rare elements such as selenium, zinc, copper, iron, manganese, calcium, and so on in various types of cells of the reproductive system could affect conception and male fertility rates. The function of trace elements in the male reproductive system could be exerted through some cellular and molecular processes, such as the management of active oxygen species, involvement in the action of membrane channels, regulation of enzyme activity, regulation of gene expression and hormone levels, and modulation of signaling cascades. In this review, we aim to summarize the available evidence on the role of trace elements in improving male reproductive performance. Also, special attention is paid to the cellular aspects and the involved molecular signaling cascades.
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Affiliation(s)
- Ali Morabbi
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Iran
| | - Mohammad Karimian
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Iran.
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2
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Hoffman KS, Chung CZ, Mukai T, Krahn N, Jiang HK, Balasuriya N, O'Donoghue P, Söll D. Recoding UAG to selenocysteine in Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2023; 29:1400-1410. [PMID: 37279998 PMCID: PMC10573291 DOI: 10.1261/rna.079658.123] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/16/2023] [Indexed: 06/08/2023]
Abstract
Unique chemical and physical properties are introduced by inserting selenocysteine (Sec) at specific sites within proteins. Recombinant and facile production of eukaryotic selenoproteins would benefit from a yeast expression system; however, the selenoprotein biosynthetic pathway was lost in the evolution of the kingdom Fungi as it diverged from its eukaryotic relatives. Based on our previous development of efficient selenoprotein production in bacteria, we designed a novel Sec biosynthesis pathway in Saccharomyces cerevisiae using Aeromonas salmonicida translation components. S. cerevisiae tRNASer was mutated to resemble A. salmonicida tRNASec to allow recognition by S. cerevisiae seryl-tRNA synthetase as well as A. salmonicida selenocysteine synthase (SelA) and selenophosphate synthetase (SelD). Expression of these Sec pathway components was then combined with metabolic engineering of yeast to enable the production of active methionine sulfate reductase enzyme containing genetically encoded Sec. Our report is the first demonstration that yeast is capable of selenoprotein production by site-specific incorporation of Sec.
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Affiliation(s)
- Kyle S Hoffman
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
| | - Christina Z Chung
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
| | - Takahito Mukai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
| | - Natalie Krahn
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
| | - Han-Kai Jiang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
| | - Nileeka Balasuriya
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Patrick O'Donoghue
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 3K7, Canada
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, USA
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3
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Mizuno A, Toyama T, Ichikawa A, Sakai N, Yoshioka Y, Nishito Y, Toga R, Amesaka H, Kaneko T, Arisawa K, Tsutsumi R, Mita Y, Tanaka SI, Noguchi N, Saito Y. An efficient selenium transport pathway of selenoprotein P utilizing a high-affinity ApoER2 receptor variant and being independent of selenocysteine lyase. J Biol Chem 2023; 299:105009. [PMID: 37406814 PMCID: PMC10407282 DOI: 10.1016/j.jbc.2023.105009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 07/07/2023] Open
Abstract
Selenoprotein P (SeP, encoded by the SELENOP gene) is a plasma protein that contains selenium in the form of selenocysteine residues (Sec, a cysteine analog containing selenium instead of sulfur). SeP functions for the transport of selenium to specific tissues in a receptor-dependent manner. Apolipoprotein E receptor 2 (ApoER2) has been identified as a SeP receptor. However, diverse variants of ApoER2 have been reported, and the details of its tissue specificity and the molecular mechanism of its efficiency remain unclear. In the present study, we found that human T lymphoma Jurkat cells have a high ability to utilize selenium via SeP, while this ability was low in human rhabdomyosarcoma cells. We identified an ApoER2 variant with a high affinity for SeP in Jurkat cells. This variant had a dissociation constant value of 0.67 nM and a highly glycosylated O-linked sugar domain. Moreover, the acidification of intracellular vesicles was necessary for selenium transport via SeP in both cell types. In rhabdomyosarcoma cells, SeP underwent proteolytic degradation in lysosomes and transported selenium in a Sec lyase-dependent manner. However, in Jurkat cells, SeP transported selenium in Sec lyase-independent manner. These findings indicate a preferential selenium transport pathway involving SeP and high-affinity ApoER2 in a Sec lyase-independent manner. Herein, we provide a novel dynamic transport pathway for selenium via SeP.
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Affiliation(s)
- Ayako Mizuno
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Takashi Toyama
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Atsuya Ichikawa
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Naoko Sakai
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Yuya Yoshioka
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Yukina Nishito
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Renya Toga
- Laboratory of Biostructural Chemistry, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Hiroshi Amesaka
- Laboratory of Biostructural Chemistry, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Takayuki Kaneko
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Kotoko Arisawa
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Ryouhei Tsutsumi
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yuichiro Mita
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Shun-Ichi Tanaka
- Laboratory of Biostructural Chemistry, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan; Department of Biotechnology, College of Life Sciences, Ritsumeikan University, Shiga, Japan
| | - Noriko Noguchi
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Yoshiro Saito
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan; The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan.
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4
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Zhao J, Zou H, Huo Y, Wei X, Li Y. Emerging roles of selenium on metabolism and type 2 diabetes. Front Nutr 2022; 9:1027629. [PMID: 36438755 PMCID: PMC9686347 DOI: 10.3389/fnut.2022.1027629] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/10/2022] [Indexed: 07/22/2023] Open
Abstract
Selenium is recognized as an essential element for human health and enters human body mainly via diet. Selenium is a key constituent in selenoproteins, which exert essential biological functions, including antioxidant and anti-inflammatory effects. Several selenoproteins including glutathione peroxidases, selenoprotein P and selenoprotein S are known to play roles in the regulation of type 2 diabetes. Although there is a close association between certain selenoproteins with glucose metabolism or insulin resistance, the relationship between selenium and type 2 diabetes is complex and remains uncertain. Here we review recent advances in the field with an emphasis on roles of selenium on metabolism and type 2 diabetes. Understanding the association between selenium and type 2 diabetes is important for developing clinical practice guidelines, establishing and implementing effective public health policies, and ultimately combating relative health issues.
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5
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Manta B, Makarova NE, Mariotti M. The selenophosphate synthetase family: A review. Free Radic Biol Med 2022; 192:63-76. [PMID: 36122644 DOI: 10.1016/j.freeradbiomed.2022.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/11/2022] [Accepted: 09/12/2022] [Indexed: 11/23/2022]
Abstract
Selenophosphate synthetases use selenium and ATP to synthesize selenophosphate. This is required for biological utilization of selenium, most notably for the synthesis of the non-canonical amino acid selenocysteine (Sec). Therefore, selenophosphate synthetases underlie all functions of selenoproteins, which include redox homeostasis, protein quality control, hormone regulation, metabolism, and many others. This protein family comprises two groups, SelD/SPS2 and SPS1. The SelD/SPS2 group represent true selenophosphate synthetases, enzymes central to selenium metabolism which are present in all Sec-utilizing organisms across the tree of life. Notably, many SelD/SPS2 proteins contain Sec as catalytic residue in their N-terminal flexible selenium-binding loop, while others replace it with cysteine (Cys). The SPS1 group comprises proteins originated through gene duplications of SelD/SPS2 in metazoa in which the Sec/Cys-dependent catalysis was disrupted. SPS1 proteins do not synthesize selenophosphate and are not required for Sec synthesis. They have essential regulatory functions related to redox homeostasis and pyridoxal phosphate, which affect signaling pathways for growth and differentiation. In this review, we summarize the knowledge about the selenophosphate synthetase family acquired through decades of research, encompassing their structure, mechanism, function, and evolution.
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Affiliation(s)
- Bruno Manta
- Laboratorio de Genómica Microbiana, Institut Pasteur Montevideo, Uruguay, Cátedra de Fisiopatología, Facultad de Odontología, Universidad de la República, Uruguay
| | - Nadezhda E Makarova
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona (UB), Avinguda Diagonal 643, Barcelona, 08028, Catalonia, Spain
| | - Marco Mariotti
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona (UB), Avinguda Diagonal 643, Barcelona, 08028, Catalonia, Spain.
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6
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Hu Y, Chai X, Men J, Rao S, Cong X, Cheng S, Qiao Z. Does Methionine Status Influence the Outcome of Selenomethinione Supplementation? A Comparative Study of Metabolic and Selenium Levels in HepG2 Cells. Nutrients 2022; 14:nu14183705. [PMID: 36145081 PMCID: PMC9506159 DOI: 10.3390/nu14183705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/05/2022] [Accepted: 09/06/2022] [Indexed: 11/16/2022] Open
Abstract
Methionine restriction and selenium supplementation are recommended because of their health benefits. As a major nutrient form in selenium supplementation, selenomethionine shares a similar biological process to its analog methionine. However, the outcome of selenomethionine supplementation under different methionine statuses and the interplay between these two nutrients remain unclear. Therefore, this study explored the metabolic effects and selenium utilization in HepG2 cells supplemented with selenomethionine under deprived, adequate, and abundant methionine supply conditions by using nuclear magnetic resonance-based metabolomic and molecular biological approaches. Results revealed that selenomethionine promoted the proliferation of HepG2 cells, the transcription of selenoproteins, and the production of most amino acids while decreasing the levels of creatine, aspartate, and nucleoside diphosphate sugar regardless of methionine supply. Selenomethionine substantially disturbed the tricarboxylic acid cycle and choline metabolism in cells under a methionine shortage. With increasing methionine supply, the metabolic disturbance was alleviated, except for changes in lactate, glycine, citrate, and hypoxanthine. The markable selenium accumulation and choline decrease in the cells under methionine shortage imply the potential risk of selenomethionine supplementation. This work revealed the biological effects of selenomethionine under different methionine supply conditions. This study may serve as a guide for controlling methionine and selenomethionine levels in dietary intake.
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Affiliation(s)
- Yili Hu
- National R&D Center for Se-Rich Agricultural Products Processing, School of Modern Industry for Selenium Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
| | - Xiaocui Chai
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Jun Men
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Shen Rao
- National R&D Center for Se-Rich Agricultural Products Processing, School of Modern Industry for Selenium Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
| | - Xin Cong
- National R&D Center for Se-Rich Agricultural Products Processing, School of Modern Industry for Selenium Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
- Research and Development Center, Enshi Se-Run Material Engineering Technology Co., Ltd., Enshi 445000, China
| | - Shuiyuan Cheng
- National R&D Center for Se-Rich Agricultural Products Processing, School of Modern Industry for Selenium Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
| | - Zhixian Qiao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- Correspondence: ; Tel.: +86-027-68780783
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7
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Zidoune H, Ladjouze A, Chellat-Rezgoune D, Boukri A, Dib SA, Nouri N, Tebibel M, Sifi K, Abadi N, Satta D, Benelmadani Y, Bignon-Topalovic J, El-Zaiat-Munsch M, Bashamboo A, McElreavey K. Novel Genomic Variants, Atypical Phenotypes and Evidence of a Digenic/Oligogenic Contribution to Disorders/Differences of Sex Development in a Large North African Cohort. Front Genet 2022; 13:900574. [PMID: 36110220 PMCID: PMC9468775 DOI: 10.3389/fgene.2022.900574] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
In a majority of individuals with disorders/differences of sex development (DSD) a genetic etiology is often elusive. However, new genes causing DSD are routinely reported and using the unbiased genomic approaches, such as whole exome sequencing (WES) should result in an increased diagnostic yield. Here, we performed WES on a large cohort of 125 individuals all of Algerian origin, who presented with a wide range of DSD phenotypes. The study excluded individuals with congenital adrenal hypoplasia (CAH) or chromosomal DSD. Parental consanguinity was reported in 36% of individuals. The genetic etiology was established in 49.6% (62/125) individuals of the total cohort, which includes 42.2% (35/83) of 46, XY non-syndromic DSD and 69.2% (27/39) of 46, XY syndromic DSD. No pathogenic variants were identified in the 46, XX DSD cases (0/3). Variants in the AR, HSD17B3, NR5A1 and SRD5A2 genes were the most common causes of DSD. Other variants were identified in genes associated with congenital hypogonadotropic hypogonadism (CHH), including the CHD7 and PROKR2. Previously unreported pathogenic/likely pathogenic variants (n = 30) involving 25 different genes were identified in 22.4% of the cohort. Remarkably 11.5% of the 46, XY DSD group carried variants classified as pathogenic/likely pathogenic variant in more than one gene known to cause DSD. The data indicates that variants in PLXNA3, a candidate CHH gene, is unlikely to be involved in CHH. The data also suggest that NR2F2 variants may cause 46, XY DSD.
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Affiliation(s)
- Housna Zidoune
- Human Developmental Genetics Unit, Institut Pasteur, CNRS, Paris, France
- Laboratory of Molecular and Cellular Biology, Department of Animal Biology, University Frères Mentouri Constantine 1, Constantine, Algeria
- Department of Medicine, Laboratory of Biology and Molecular Genetics, University Salah Boubnider Constantine 3, Constantine, Algeria
| | | | - Djalila Chellat-Rezgoune
- Laboratory of Molecular and Cellular Biology, Department of Animal Biology, University Frères Mentouri Constantine 1, Constantine, Algeria
- Department of Medicine, Laboratory of Biology and Molecular Genetics, University Salah Boubnider Constantine 3, Constantine, Algeria
| | - Asma Boukri
- Department of Endocrinology and Diabetology, CHU Ibn Badis Constantine, Constantine, Algeria
| | | | - Nassim Nouri
- Department of Endocrinology and Diabetology, CHU Ibn Badis Constantine, Constantine, Algeria
| | - Meryem Tebibel
- Department of Pediatric Surgery, CHU Beni Messous, Algiers, Algeria
| | - Karima Sifi
- Department of Medicine, Laboratory of Biology and Molecular Genetics, University Salah Boubnider Constantine 3, Constantine, Algeria
| | - Noureddine Abadi
- Department of Medicine, Laboratory of Biology and Molecular Genetics, University Salah Boubnider Constantine 3, Constantine, Algeria
| | - Dalila Satta
- Laboratory of Molecular and Cellular Biology, Department of Animal Biology, University Frères Mentouri Constantine 1, Constantine, Algeria
- Department of Medicine, Laboratory of Biology and Molecular Genetics, University Salah Boubnider Constantine 3, Constantine, Algeria
| | - Yasmina Benelmadani
- Department of Medicine, Laboratory of Biology and Molecular Genetics, University Salah Boubnider Constantine 3, Constantine, Algeria
| | | | | | - Anu Bashamboo
- Human Developmental Genetics Unit, Institut Pasteur, CNRS, Paris, France
| | - Ken McElreavey
- Human Developmental Genetics Unit, Institut Pasteur, CNRS, Paris, France
- *Correspondence: Ken McElreavey,
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8
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Dirice E, Basile G, Kahraman S, Diegisser D, Hu J, Kulkarni RN. Single-nucleus RNA-sequencing reveals singular gene signatures of human ductal cells during adaptation to insulin resistance. JCI Insight 2022; 7:153877. [PMID: 35819843 PMCID: PMC9462484 DOI: 10.1172/jci.insight.153877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 07/07/2022] [Indexed: 11/26/2022] Open
Abstract
Adaptation to increased insulin demand is mediated by β cell proliferation and neogenesis, among other mechanisms. Although it is known that pancreatic β cells can arise from ductal progenitors, these observations have been limited mostly to the neonatal period. We have recently reported that the duct is a source of insulin-secreting cells in adult insulin-resistant states. To further explore the signaling pathways underlying the dynamic β cell reserve during insulin resistance, we undertook human islet and duct transplantations under the kidney capsule of immunodeficient NOD/SCID-γ (NSG) mouse models that were pregnant, were insulin-resistant, or had insulin resistance superimposed upon pregnancy (insulin resistance + pregnancy), followed by single-nucleus RNA-Seq (snRNA-Seq) on snap-frozen graft samples. We observed an upregulation of proliferation markers (e.g., NEAT1) and expression of islet endocrine cell markers (e.g., GCG and PPY), as well as mature β cell markers (e.g., INS), in transplanted human duct grafts in response to high insulin demand. We also noted downregulation of ductal cell identity genes (e.g., KRT19 and ONECUT2) coupled with upregulation of β cell development and insulin signaling pathways. These results indicate that subsets of ductal cells are able to gain β cell identity and reflect a form of compensation during the adaptation to insulin resistance in both physiological and pathological states.
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Affiliation(s)
- Ercument Dirice
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Giorgio Basile
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Sevim Kahraman
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Danielle Diegisser
- Department of Pharmacology, New York Medical College, Valhalla, United States of America
| | - Jiang Hu
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Rohit N Kulkarni
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
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9
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Kitabayashi N, Nakao S, Mita Y, Arisawa K, Hoshi T, Toyama T, Ishii KA, Takamura T, Noguchi N, Saito Y. Role of selenoprotein P expression in the function of pancreatic β cells: Prevention of ferroptosis-like cell death and stress-induced nascent granule degradation. Free Radic Biol Med 2022; 183:89-103. [PMID: 35318102 DOI: 10.1016/j.freeradbiomed.2022.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/07/2022] [Accepted: 03/11/2022] [Indexed: 02/05/2023]
Abstract
Selenoprotein P (SELENOP) is a major selenium (Se)-containing protein (selenoprotein) in human plasma that is mainly synthesized in the liver. SELENOP transports Se to the cells, while SELENOP synthesized in peripheral tissues is incorporated in a paracrine/autocrine manner to maintain the levels of cellular selenoproteins, called the SELENOP cycle. Pancreatic β cells, responsible for the synthesis and secretion of insulin, are known to express SELENOP. Here, using MIN6 cells as a mouse model for pancreatic β cells and Selenop small interfering (si)RNA, we found that Selenop gene knockdown (KD) resulted in decreased cell viability, cellular pro/insulin levels, insulin secretion, and levels of several cellular selenoproteins, including glutathione peroxidase 4 (Gpx4) and selenoprotein K (Selenok). These dysfunctions induced by Selenop siRNA were recovered by the addition of Se. Ferroptosis-like cell death, regulated by Gpx4, was involved in the decrease of cell viability by Selenop KD, while stress-induced nascent granule degradation (SINGD), regulated by Selenok, was responsible for the decrease in proinsulin. SINGD was also observed in the pancreatic β cells of Selenop knockout mice. These findings indicate a significant role of SELENOP expression for the function of pancreatic β cells by maintaining the levels of cellular selenoproteins such as GPX4 and SELENOK.
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Affiliation(s)
- Nanako Kitabayashi
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, 610-0394, Japan
| | - Shohei Nakao
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, 610-0394, Japan
| | - Yuichiro Mita
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, 610-0394, Japan
| | - Kotoko Arisawa
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Takayuki Hoshi
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Takashi Toyama
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Kiyo-Aki Ishii
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
| | - Toshinari Takamura
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
| | - Noriko Noguchi
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, 610-0394, Japan
| | - Yoshiro Saito
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, 610-0394, Japan; Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan.
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10
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Oikawa T, Okajima K, Yamanaka K, Kato S. First enzymological characterization of selenocysteine β-lyase from a lactic acid bacterium, Leuconostoc mesenteroides. Amino Acids 2022; 54:787-798. [PMID: 35122135 DOI: 10.1007/s00726-022-03133-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 01/20/2022] [Indexed: 11/24/2022]
Abstract
We succeeded in expressing selenocysteine β-lyase (SCL) from a lactic acid bacterium, Leuconostoc mesenteroides LK-151 (Lm-SCL), in the soluble fractions of Escherichia coli Rosetta (DE3) using a novel expression vector of pET21malb constructed by ourselves that has both maltose binding protein (MBP)- and 6 × His-tag. Lm-SCL acted on L-selenocysteine, L-cysteine, and L-cysteine sulfinic acid but showed a high preference for L-selenocysteine. The kcat and kcat/Km values of Lm-SCL were determined to be 108 (min-1) and 42.0 (min-1・mM-1), respectively, and this was enough catalytic efficiency to suggest that Lm-SCL might also be involved in supplying elemental selenium from L-selenocysteine to selenoproteins like other SCLs. The optimum temperature and optimum pH of Lm-SCL were determined to be 37 °C and pH 6.5, respectively. Lm-SCL was stable at 37-45 °C and pH 6.5-7.5. Lm-SCL was completely inhibited by the addition of hydroxylamine, semicarbazide, and iodoacetic acid. The enzyme activity of Lm-SCL was decreased in the presence of various metal ions, especially Cu2+. The quaternary structure of Lm-SCL is a homodimer with a subunit molecular mass of 47.5 kDa. The similarity of the primary structure of Lm-SCL to other SCLs from Citrobacter freundii, Escherichia coli, humans, or mouse was calculated to be 47.0, 48.0, 12.5, or 24.0%, respectively. Unlike Ec-SCL, our mutational and molecular docking simulation studies revealed that C362 of Lm-SCL might also catalyze the deselenation of L-selenocysteine in addition to the desulfuration of L-cysteine.
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Affiliation(s)
- Tadao Oikawa
- Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-Cho, Suita, Osaka-Fu, 564-8680, Japan.
| | - Kouhei Okajima
- Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-Cho, Suita, Osaka-Fu, 564-8680, Japan
| | - Kazuya Yamanaka
- Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-Cho, Suita, Osaka-Fu, 564-8680, Japan
| | - Shiro Kato
- International Institute of Rare Sugar Research and Education, Kagawa University, 2393 Ikenobe, Miki, Kagawa, 761-0795, Japan
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11
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Lima LW, Nardi S, Santoro V, Schiavon M. The Relevance of Plant-Derived Se Compounds to Human Health in the SARS-CoV-2 (COVID-19) Pandemic Era. Antioxidants (Basel) 2021; 10:antiox10071031. [PMID: 34202330 PMCID: PMC8300636 DOI: 10.3390/antiox10071031] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/20/2021] [Accepted: 06/23/2021] [Indexed: 12/27/2022] Open
Abstract
Dietary selenium (Se)-compounds accumulated in plants are essential for human metabolism and normal physiological processes. Inorganic and organic Se species can be readily absorbed by the human body, but are metabolized differently and thus exhibit distinct mechanisms of action. They can act as antioxidants or serve as a source of Se for the synthesis of selenoproteins. Selenocysteine, in particular, is incorporated at the catalytic center of these proteins through a specific insertion mechanism and, due to its electronic features, enhances their catalytic activity against biological oxidants. Selenite and other Se-organic compounds may also act as direct antioxidants in cells due to their strong nucleophilic properties. In addition, Se-amino acids are more easily subjected to oxidation than the corresponding thiols/thioethers and can bind redox-active metal ions. Adequate Se intake aids in preventing several metabolic disorders and affords protection against viral infections. At present, an epidemic caused by a novel coronavirus (SARS-CoV-2) threatens human health across several countries and impacts the global economy. Therefore, Se-supplementation could be a complementary treatment to vaccines and pharmacological drugs to reduce the viral load, mutation frequency, and enhance the immune system of populations with low Se intake in the diet.
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Affiliation(s)
| | - Serenella Nardi
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell’Università 16, 35020 Legnaro, PD, Italy;
| | - Veronica Santoro
- Department of Agricultural, Forest and Food Sciences (DISAFA), University of Turin, Via Leonardo da Vinci, 44, 10095 Grugliasco, TO, Italy;
| | - Michela Schiavon
- Department of Agricultural, Forest and Food Sciences (DISAFA), University of Turin, Via Leonardo da Vinci, 44, 10095 Grugliasco, TO, Italy;
- Correspondence: ; Tel.: +1-1670-8520
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12
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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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13
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Johnstone MA, Nelson SJ, O'Leary C, Self WT. Exploring the selenium-over-sulfur substrate specificity and kinetics of a bacterial selenocysteine lyase. Biochimie 2021; 182:166-176. [PMID: 33444662 DOI: 10.1016/j.biochi.2021.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/28/2020] [Accepted: 01/04/2021] [Indexed: 11/15/2022]
Abstract
Selenium is a vital micronutrient in many organisms. While traces are required for microbial utilization, excess amounts are toxic; thus, selenium can be regarded as a biological double-edged sword. Selenium is chemically similar to the essential element sulfur, but curiously, evolution has selected the former over the latter for a subset of oxidoreductases. Enzymes involved in sulfur metabolism are less discriminate in terms of preventing selenium incorporation; however, its specific incorporation into selenoproteins reveals a highly discriminate process that is not completely understood. We have identified SclA, a NifS-like protein in the nosocomial pathogen, Enterococcus faecalis, and characterized its enzymatic activity and specificity for l-selenocysteine over l-cysteine. It is known that Asp-146 is required for selenocysteine specificity in the human selenocysteine lyase. Thus, using computational biology, we compared the bacterial and mammalian enzymes and identified His-100, an Asp-146 ortholog in SclA, and generated site-directed mutants in order to study the residue's potential role in the l-selenocysteine discrimination mechanism. The proteins were overexpressed, purified, and characterized for their biochemical properties. All mutants exhibited varying Michaelis-Menten behavior towards l-selenocysteine, but His-100 was not found to be essential for this activity. Additionally, l-cysteine acted as a competitive inhibitor of all enzymes with higher affinity than l-selenocysteine. Finally, we discovered that SclA exhibited low activity with l-cysteine as a poor substrate regardless of mutations. We conclude that His-100 is not required for l-selenocysteine specificity, underscoring the inherent differences in discriminatory mechanisms between bacterial NifS-like proteins and mammalian selenocysteine lyases.
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Affiliation(s)
- Michael A Johnstone
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32816, USA
| | - Samantha J Nelson
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32816, USA
| | - Christine O'Leary
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32816, USA
| | - William T Self
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32816, USA.
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14
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Ralston NV, Raymond LJ. Soft electrophile inhibition of selenoenzymes in disease pathologies. Toxicology 2021. [DOI: 10.1016/b978-0-12-819092-0.00040-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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15
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Scortecci JF, Serrão VHB, Fernandes AF, Basso LG, Gutierrez RF, Araujo APU, Neto MO, Thiemann OH. Initial steps in selenocysteine biosynthesis: The interaction between selenocysteine lyase and selenophosphate synthetase. Int J Biol Macromol 2020; 156:18-26. [DOI: 10.1016/j.ijbiomac.2020.03.241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 02/29/2020] [Accepted: 03/28/2020] [Indexed: 10/24/2022]
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16
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Saito Y. Selenoprotein P as a significant regulator of pancreatic β cell function. J Biochem 2020; 167:119-124. [PMID: 31373634 DOI: 10.1093/jb/mvz061] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/01/2019] [Indexed: 02/05/2023] Open
Abstract
Selenoprotein P (SeP; encoded by SELENOP) is selenium (Se)-rich plasma protein that is mainly produced in the liver. SeP functions as a Se-transport protein to deliver Se from the liver to other tissues, such as the brain and testis. The protein plays a pivotal role in Se metabolism and antioxidative defense, and it has been identified as a 'hepatokine' that causes insulin resistance in type 2 diabetes. SeP levels are increased in type 2 diabetes patients, and excess SeP impairs insulin signalling, promoting insulin resistance. Furthermore, increased levels of SeP disturb the functioning of pancreatic β cells and inhibit insulin secretion. This review focuses on the biological function of SeP and the molecular mechanisms associated with the adverse effects of excess SeP on pancreatic β cells' function, particularly with respect to redox reactions. Interactions between the liver and pancreas are also discussed.
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Affiliation(s)
- Yoshiro Saito
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, C301, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, Japan
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17
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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: 72] [Impact Index Per Article: 14.4] [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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18
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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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19
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Torres DJ, Pitts MW, Hashimoto AC, Berry MJ. Agrp-Specific Ablation of Scly Protects against Diet-Induced Obesity and Leptin Resistance. Nutrients 2019; 11:nu11071693. [PMID: 31340540 PMCID: PMC6682868 DOI: 10.3390/nu11071693] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/18/2019] [Accepted: 07/20/2019] [Indexed: 01/25/2023] Open
Abstract
Selenium, an essential trace element known mainly for its antioxidant properties, is critical for proper brain function and regulation of energy metabolism. Whole-body knockout of the selenium recycling enzyme, selenocysteine lyase (Scly), increases susceptibility to metabolic syndrome and diet-induced obesity in mice. Scly knockout mice also have decreased selenoprotein expression levels in the hypothalamus, a key regulator of energy homeostasis. This study investigated the role of selenium in whole-body metabolism regulation using a mouse model with hypothalamic knockout of Scly. Agouti-related peptide (Agrp) promoter-driven Scly knockout resulted in reduced weight gain and adiposity while on a high-fat diet (HFD). Scly-Agrp knockout mice had reduced Agrp expression in the hypothalamus, as measured by Western blot and immunohistochemistry (IHC). IHC also revealed that while control mice developed HFD-induced leptin resistance in the arcuate nucleus, Scly-Agrp knockout mice maintained leptin sensitivity. Brown adipose tissue from Scly-Agrp knockout mice had reduced lipid deposition and increased expression of the thermogenic marker uncoupled protein-1. This study sheds light on the important role of selenium utilization in energy homeostasis, provides new information on the interplay between the central nervous system and whole-body metabolism, and may help identify key targets of interest for therapeutic treatment of metabolic disorders.
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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, Honolulu, HI 96813, USA
| | - Matthew W Pitts
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i, Honolulu, HI 96813, USA
| | - Ann C Hashimoto
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i, Honolulu, HI 96813, USA
| | - Marla J Berry
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i, Honolulu, HI 96813, USA.
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20
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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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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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22
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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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23
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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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24
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Jahan MI, Tobe R, Mihara H. Characterization of a Novel Porin-Like Protein, ExtI, from Geobacter sulfurreducens and Its Implication in the Reduction of Selenite and Tellurite. Int J Mol Sci 2018. [PMID: 29534491 PMCID: PMC5877670 DOI: 10.3390/ijms19030809] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The extI gene in Geobacter sulfurreducens encodes a putative outer membrane channel porin, which resides within a cluster of extHIJKLMNOPQS genes. This cluster is highly conserved across the Geobacteraceae and includes multiple putative c-type cytochromes. In silico analyses of the ExtI sequence, together with Western blot analysis and proteinase protection assays, showed that it is an outer membrane protein. The expression level of ExtI did not respond to changes in osmolality and phosphate starvation. An extI-deficient mutant did not show any significant impact on fumarate or Fe(III) citrate reduction or sensitivity to β-lactam antibiotics, as compared with those of the wild-type strain. However, extI deficiency resulted in a decreased ability to reduce selenite and tellurite. Heme staining analysis revealed that extI deficiency affects certain heme-containing proteins in the outer and inner membranes, which may cause a decrease in the ability to reduce selenite and tellurite. Based on these observations, we discuss possible roles for ExtI in selenite and tellurite reduction in G. sulfurreducens.
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Affiliation(s)
- Mst Ishrat Jahan
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
| | - Ryuta Tobe
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
| | - Hisaaki Mihara
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
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25
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Imai T, Kurihara T, Esaki N, Mihara H. Selective fluorescence detection method for selenide and selenol using monochlorobimane. Anal Biochem 2017; 532:1-8. [DOI: 10.1016/j.ab.2017.05.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/18/2017] [Accepted: 05/22/2017] [Indexed: 02/06/2023]
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26
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França MR, da Silva MIS, Pugliesi G, Van Hoeck V, Binelli M. Evidence of endometrial amino acid metabolism and transport modulation by peri-ovulatory endocrine profiles driving uterine receptivity. J Anim Sci Biotechnol 2017. [PMID: 28630707 PMCID: PMC5472857 DOI: 10.1186/s40104-017-0185-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Background In beef cattle, changes in the periovulatory endocrine milieu are associated with fertility and conceptus growth. A large preovulatory follicle (POF) and the resulting elevated concentrations of progesterone (P4) during diestrus positively affect pregnancy rates. Amino acids (AA) are important components of maternally derived secretions that are crucial for embryonic survival before implantation. The hypothesis is that the size of the POF and the concentration of P4 in early diestrus modulate the endometrial abundance of SLC transcripts related to AA transport and metabolism and subsequently impact luminal concentrations of AA. The follicle growth of Nelore cows was manipulated to produce two experimental groups: large POF and CL (LF-LCL group) and small POF and CL (SF-SCL group). On Day 4 (D4; Experiment 1) and Day 7 (D7; Experiment 2) after GnRH-induced ovulation (GnRH treatment = D0), the animals were slaughtered and uterine tissues and uterine washings were collected. qRT-PCR was used to evaluate the expression levels of AA transporters in D4 and D7 endometrial tissues. The concentrations of AA were quantified in D4 and D7 uterine washings by HPLC. Results Transcript results show that, on D4, SLC6A6, SLC7A4, SLC17A5, SLC38A1, SLC38A7 and SCLY and on D7 SLC1A4, SLC6A1, SLC6A14, SLC7A4, SLC7A7, SLC7A8, SLC17A5, SLC38A1, SLC38A7, SLC43A2 and DDO were more abundant in the endometria of cows from the LF-LCL group (P < 0.05). In addition, concentrations of AA in the uterine lumen were influenced by the endocrine profiles of the mother. In this context, D4 uterine washings revealed that greater concentrations of taurine, alanine and α-aminobutyric acid were present in SF-SCL (P < 0.05). In contrast, lower concentrations of valine and cystathionine were quantified on D7 uterine washings from SF-SCL cows (P < 0.05). Conclusion The present study revealed an association between the abundance of transcripts related to AA transport and metabolism in the endometrium and specific periovulatory endocrine profiles related to the receptive status of the mother. Such insights suggest that AAs are involved in uterine function to support embryo development.
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Affiliation(s)
- Moana Rodrigues França
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, 225, Duque de Caxias Norte Ave. Jd. Elite, 13635-900 Pirassununga, SP Brazil
| | - Maressa Izabel Santos da Silva
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, 225, Duque de Caxias Norte Ave. Jd. Elite, 13635-900 Pirassununga, SP Brazil
| | - Guilherme Pugliesi
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, 225, Duque de Caxias Norte Ave. Jd. Elite, 13635-900 Pirassununga, SP Brazil
| | | | - Mario Binelli
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, 225, Duque de Caxias Norte Ave. Jd. Elite, 13635-900 Pirassununga, SP Brazil
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Gao C, Hsu FC, Dimitrov LM, Okut H, Chen YDI, Taylor KD, Rotter JI, Langefeld CD, Bowden DW, Palmer ND. A genome-wide linkage and association analysis of imputed insertions and deletions with cardiometabolic phenotypes in Mexican Americans: The Insulin Resistance Atherosclerosis Family Study. Genet Epidemiol 2017; 41:353-362. [PMID: 28378447 DOI: 10.1002/gepi.22042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 12/23/2016] [Accepted: 02/04/2017] [Indexed: 11/09/2022]
Abstract
Insertions and deletions (INDELs) represent a significant fraction of interindividual variation in the human genome yet their contribution to phenotypes is poorly understood. To confirm the quality of imputed INDELs and investigate their roles in mediating cardiometabolic phenotypes, genome-wide association and linkage analyses were performed for 15 phenotypes with 1,273,952 imputed INDELs in 1,024 Mexican-origin Americans. Imputation quality was validated using whole exome sequencing with an average kappa of 0.93 in common INDELs (minor allele frequencies [MAFs] ≥ 5%). Association analysis revealed one genome-wide significant association signal for the cholesterylester transfer protein gene (CETP) with high-density lipoprotein levels (rs36229491, P = 3.06 × 10-12 ); linkage analysis identified two peaks with logarithm of the odds (LOD) > 5 (rs60560566, LOD = 5.36 with insulin sensitivity (SI ) and rs5825825, LOD = 5.11 with adiponectin levels). Suggestive overlapping signals between linkage and association were observed: rs59849892 in the WSC domain containing 2 gene (WSCD2) was associated and nominally linked with SI (P = 1.17 × 10-7 , LOD = 1.99). This gene has been implicated in glucose metabolism in human islet cell expression studies. In addition, rs201606363 was linked and nominally associated with low-density lipoprotein (P = 4.73 × 10-4 , LOD = 3.67), apolipoprotein B (P = 1.39 × 10-3 , LOD = 4.64), and total cholesterol (P = 1.35 × 10-2 , LOD = 3.80) levels. rs201606363 is an intronic variant of the UBE2F-SCLY (where UBE2F is ubiquitin-conjugating enzyme E2F and SCLY is selenocysteine lyase) fusion gene that may regulate cholesterol through selenium metabolism. In conclusion, these results confirm the feasibility of imputing INDELs from array-based single nucleotide polymorphism (SNP) genotypes. Analysis of these variants using association and linkage replicated previously identified SNP signals and identified multiple novel INDEL signals. These results support the inclusion of INDELs into genetic studies to more fully interrogate the spectrum of genetic variation.
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Affiliation(s)
- Chuan Gao
- Molecular Genetics and Genomics Program, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.,Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.,Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Fang-Chi Hsu
- Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Latchezar M Dimitrov
- Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Hayrettin Okut
- Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Yii-Der I Chen
- Institute for Translational Genomics and Population Sciences, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America.,Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Kent D Taylor
- Institute for Translational Genomics and Population Sciences, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America.,Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Jerome I Rotter
- Institute for Translational Genomics and Population Sciences, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America.,Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Carl D Langefeld
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.,Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Donald W Bowden
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.,Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Nicholette D Palmer
- Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.,Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.,Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.,Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
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Abstract
Selenocysteine is a naturally occurring analog of cysteine in which the sulfur atom of the latter is replaced with selenium. This seleno-amino acid occurs as a specific component of various selenoproteins and selenium-dependent enzymes. Incorporation of selenocysteine into these proteins occurs cotranslationally as directed by the UGA codon. For this process, a special tRNA having an anticodon complimentary to UGA, tRNASec, is utilized. In Escherichia coli and related bacteria, this tRNA first is amino acylated with serine, and the seryl-tRNASec is converted to selenocysteyl-tRNASec. The specific incorporation of selenocysteine into proteins directed by the UGA codon depends on the synthesis of selenocysteyl-tRNASec. Included in the selenium delivery protein category are rhodaneses that mobilize selenium from inorganic sources and NIFS-like proteins that liberate elemental selenium from selenocysteine. The NIFS protein from Azotobacter vinelandii was found to serve as an efficient catalyst in vitro for delivery of selenium from free selenocysteine to Escherichia coli selenophosphate synthetase for selenophosphate formation. The widespread distribution of selenocysteine lyase in numerous bacterial species was reported and the bacterial enzymes, like the pig liver enzyme, required pyridoxal phosphate as cofactor. Three NIFS-like genes were isolated from E. coli by Esaki and coworkers and the expressed gene products were isolated and characterized. One of these NIFS-like proteins also exhibited a high preference for selenocysteine over cysteine. M. vannielii, an anaerobic methane-producing organism, that grows in a mineral medium containing formate as sole organic carbon source, synthesizes several specific selenoenzymes required for growth and energy production under these conditions.
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Laitinen VH, Rantapero T, Fischer D, Vuorinen EM, Tammela TL, Wahlfors T, Schleutker J. Fine-mapping the 2q37 and 17q11.2-q22 loci for novel genes and sequence variants associated with a genetic predisposition to prostate cancer. Int J Cancer 2015; 136:2316-27. [PMID: 25335771 PMCID: PMC4355047 DOI: 10.1002/ijc.29276] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 10/01/2014] [Indexed: 01/13/2023]
Abstract
The 2q37 and 17q12-q22 loci are linked to an increased prostate cancer (PrCa) risk. No candidate gene has been localized at 2q37 and the HOXB13 variant G84E only partially explains the linkage to 17q21-q22 observed in Finland. We screened these regions by targeted DNA sequencing to search for cancer-associated variants. Altogether, four novel susceptibility alleles were identified. Two ZNF652 (17q21.3) variants, rs116890317 and rs79670217, increased the risk of both sporadic and hereditary PrCa (rs116890317: OR = 3.3-7.8, p = 0.003-3.3 × 10(-5) ; rs79670217: OR = 1.6-1.9, p = 0.002-0.009). The HDAC4 (2q37.2) variant rs73000144 (OR = 14.6, p = 0.018) and the EFCAB13 (17q21.3) variant rs118004742 (OR = 1.8, p = 0.048) were overrepresented in patients with familial PrCa. To map the variants within 2q37 and 17q11.2-q22 that may regulate PrCa-associated genes, we combined DNA sequencing results with transcriptome data obtained by RNA sequencing. This expression quantitative trait locus (eQTL) analysis identified 272 single-nucleotide polymorphisms (SNPs) possibly regulating six genes that were differentially expressed between cases and controls. In a modified approach, prefiltered PrCa-associated SNPs were exploited and interestingly, a novel eQTL targeting ZNF652 was identified. The novel variants identified in this study could be utilized for PrCa risk assessment, and they further validate the suggested role of ZNF652 as a PrCa candidate gene. The regulatory regions discovered by eQTL mapping increase our understanding of the relationship between regulation of gene expression and susceptibility to PrCa and provide a valuable starting point for future functional research.
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Affiliation(s)
- Virpi H. Laitinen
- BioMediTech, University of Tampere and Fimlab Laboratories, FI-33520 Tampere, Finland
| | - Tommi Rantapero
- BioMediTech, University of Tampere and Fimlab Laboratories, FI-33520 Tampere, Finland
| | - Daniel Fischer
- School of Health Sciences, University of Tampere, FI-33014 Tampere, Finland
| | - Elisa M. Vuorinen
- BioMediTech, University of Tampere and Fimlab Laboratories, FI-33520 Tampere, Finland
| | - Teuvo L.J. Tammela
- Department of Urology, Tampere University Hospital and Medical School, University of Tampere, FI-33520 Tampere, Finland
| | | | - Tiina Wahlfors
- BioMediTech, University of Tampere and Fimlab Laboratories, FI-33520 Tampere, Finland
| | - Johanna Schleutker
- BioMediTech, University of Tampere and Fimlab Laboratories, FI-33520 Tampere, Finland
- Medical Biochemistry and Genetics, Institute of Biomedicine, FI-20014 University of Turku, Turku, Finland
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Labunskyy VM, Hatfield DL, Gladyshev VN. Selenoproteins: molecular pathways and physiological roles. Physiol Rev 2014; 94:739-77. [PMID: 24987004 DOI: 10.1152/physrev.00039.2013] [Citation(s) in RCA: 829] [Impact Index Per Article: 82.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Selenium is an essential micronutrient with important functions in human health and relevance to several pathophysiological conditions. The biological effects of selenium are largely mediated by selenium-containing proteins (selenoproteins) that are present in all three domains of life. Although selenoproteins represent diverse molecular pathways and biological functions, all these proteins contain at least one selenocysteine (Sec), a selenium-containing amino acid, and most serve oxidoreductase functions. Sec is cotranslationally inserted into nascent polypeptide chains in response to the UGA codon, whose normal function is to terminate translation. To decode UGA as Sec, organisms evolved the Sec insertion machinery that allows incorporation of this amino acid at specific UGA codons in a process requiring a cis-acting Sec insertion sequence (SECIS) element. Although the basic mechanisms of Sec synthesis and insertion into proteins in both prokaryotes and eukaryotes have been studied in great detail, the identity and functions of many selenoproteins remain largely unknown. In the last decade, there has been significant progress in characterizing selenoproteins and selenoproteomes and understanding their physiological functions. We discuss current knowledge about how these unique proteins perform their functions at the molecular level and highlight new insights into the roles that selenoproteins play in human health.
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Affiliation(s)
- Vyacheslav M Labunskyy
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts; and Molecular Biology of Selenium Section, Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Dolph L Hatfield
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts; and Molecular Biology of Selenium Section, Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Vadim N Gladyshev
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts; and Molecular Biology of Selenium Section, Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
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Seale LA, Gilman CL, Moorman BP, Berry MJ, Grau EG, Seale AP. Effects of acclimation salinity on the expression of selenoproteins in the tilapia, Oreochromis mossambicus. J Trace Elem Med Biol 2014; 28:284-92. [PMID: 24854764 PMCID: PMC4082732 DOI: 10.1016/j.jtemb.2014.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 04/02/2014] [Accepted: 04/15/2014] [Indexed: 01/06/2023]
Abstract
Selenoproteins are ubiquitously expressed, act on a variety of physiological redox-related processes, and are mostly regulated by selenium levels in animals. To date, the expression of most selenoproteins has not been verified in euryhaline fish models. The Mozambique tilapia, Oreochromis mossambicus, a euryhaline cichlid fish, has a high tolerance for changes in salinity and survives in fresh water (FW) and seawater (SW) environments which differ greatly in selenium availability. In the present study, we searched EST databases for cichlid selenoprotein mRNAs and screened for their differential expression in FW and SW-acclimated tilapia. The expression of mRNAs encoding iodothyronine deiodinases 1, 2 and 3 (Dio1, Dio2, Dio3), Fep15, glutathione peroxidase 2, selenoproteins J, K, L, M, P, S, and W, was measured in the brain, eye, gill, kidney, liver, pituitary, muscle, and intraperitoneal white adipose tissue. Gene expression of selenophosphate synthetase 1, Secp43, and selenocysteine lyase, factors involved in selenoprotein synthesis or in selenium metabolism, were also measured. The highest variation in selenoprotein and synthesis factor mRNA expression between FW- and SW-acclimated fish was found in gill and kidney. While the branchial expression of Dio3 was increased upon transferring tilapia from SW to FW, the inverse effect was observed when fish were transferred from FW to SW. Protein content of Dio3 was higher in fish acclimated to FW than in those acclimated to SW. Together, these results outline tissue distribution of selenoproteins in FW and SW-acclimated tilapia, and indicate that at least Dio3 expression is regulated by environmental salinity.
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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, USA.
| | - Christy L Gilman
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA
| | - Benjamin P Moorman
- Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA
| | - Marla J Berry
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA
| | - E Gordon Grau
- Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA
| | - Andre P Seale
- Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA
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32
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Mao J, Teng W. The relationship between selenoprotein P and glucose metabolism in experimental studies. Nutrients 2013; 5:1937-48. [PMID: 23760059 PMCID: PMC3725484 DOI: 10.3390/nu5061937] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/30/2013] [Accepted: 05/06/2013] [Indexed: 11/17/2022] Open
Abstract
Selenium is an essential trace element in the diet of mammals which is important for many physiological functions. However, a number of epidemiological studies have suggested that high selenium status is a possible risk factor for the development of type 2 diabetes, although they cannot distinguish between cause and effect. Selenoprotein P (Sepp1) is central to selenium homeostasis and widely expressed in the organism. Here we review the interaction between Sepp1 and glucose metabolism with an emphasis on experimental evidence. In models with or without gene modification, glucose and insulin can regulate Sepp1 expression in the pancreas and liver, and vice versa. Especially in the liver, Sepp1 is regulated virtually like a gluconeogenic enzyme. Combining these data suggests that there could be a feedback regulation between hepatic Sepp1 and pancreatic insulin and that increasing circulating Sepp1 might be the result rather than the cause of abnormal glucose metabolism. Future studies specifically designed to overexpress Sepp1 are needed in order to provide a more robust link between Sepp1 and type 2 diabetes.
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Affiliation(s)
- Jinyuan Mao
- Liaoning Provincial Key Laboratory of Endocrine Diseases, Department of Endocrinology and Metabolism, Institute of Endocrinology, The First Affiliated Hospital of China Medical University, No.155, North Nanjing Street, Shenyang 110001, China.
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Manzine LR, Serrão VHB, Lima LMTDRE, de Souza MM, Bettini J, Portugal RV, van Heel M, Thiemann OH. Assembly stoichiometry of bacterial selenocysteine synthase and SelC (tRNAsec). FEBS Lett 2013; 587:906-11. [DOI: 10.1016/j.febslet.2013.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 01/09/2013] [Accepted: 02/06/2013] [Indexed: 11/24/2022]
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Krol MB, Gromadzinska J, Wasowicz W. SeP, ApoER2 and megalin as necessary factors to maintain Se homeostasis in mammals. J Trace Elem Med Biol 2012; 26:262-6. [PMID: 22683052 DOI: 10.1016/j.jtemb.2012.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 03/19/2012] [Indexed: 11/23/2022]
Abstract
Selenoprotein P (SeP) is an extracellular protein containing ten selenium atoms in the form of selenocysteine, secreted mainly from the liver. About 60% of the whole plasma selenium level is present in SeP, which makes it a useful biomarker of selenium nutritional status. The main functions of SeP are transport and storage of selenium in plasma. It is especially an important protein for the brain, testes and kidneys where the supplementation of the proper amount of Se ensures the synthesis of selenoenzymes with antioxidant properties.Recently, it has been found that SeP uptake in kidneys, testes and brain depends on the apolipoprotein receptor 2 (ApoER2) and lipoprotein megalin receptor (Lrp2). Megalin receptor represents a physiological SeP receptor in kidneys, mediating the re-uptake of secreted SeP from the primary urine. The absence of a functional megalin receptor causes a significant reduction of plasma selenium and the SeP levels as a result of Se excretion. ApoER2 is a SeP receptor in the brain and testes which uptakes Se from the extracellular fluid. Deletion of ApoER2 in mice leads to a lowered selenium level in the brain and testes, neurological dysfunction, production of abnormal spermatozoa, infertility and even death when the subjects are fed a low-selenium diet.
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Affiliation(s)
- Magdalena Beata Krol
- Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Lodz, Poland.
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35
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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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Raman AV, Pitts MW, Seyedali A, Hashimoto AC, Seale LA, Bellinger FP, Berry MJ. Absence of selenoprotein P but not selenocysteine lyase results in severe neurological dysfunction. GENES BRAIN AND BEHAVIOR 2012; 11:601-13. [PMID: 22487427 DOI: 10.1111/j.1601-183x.2012.00794.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Dietary selenium restriction in mammals causes bodily selenium to be preferentially retained in the brain relative to other organs. Almost all the known selenoproteins are found in brain, where expression is facilitated by selenocysteine (Sec)-laden selenoprotein P. The brain also expresses selenocysteine lyase (Scly), an enzyme that putatively salvages Sec and recycles the selenium for selenoprotein translation. We compared mice with a genetic deletion of Scly to selenoprotein P (Sepp1) knockout mice for similarity of neurological impairments and whether dietary selenium modulates these parameters. We report that Scly knockout mice do not display neurological dysfunction comparable to Sepp1 knockout mice. Feeding a low-selenium diet to Scly knockout mice revealed a mild spatial learning deficit without disrupting motor coordination. Additionally, we report that the neurological phenotype caused by the absence of Sepp1 is exacerbated in male vs. female mice. These findings indicate that Sec recycling via Scly becomes limiting under selenium deficiency and suggest the presence of a complementary mechanism for processing Sec. Our studies illuminate the interaction between Sepp1 and Scly in the distribution and turnover of body and brain selenium and emphasize the consideration of sex differences when studying selenium and selenoproteins in vertebrate biology.
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Affiliation(s)
- A V Raman
- Cell and Molecular Biology Department, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, 96813, USA
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Kurokawa S, Takehashi M, Tanaka H, Mihara H, Kurihara T, Tanaka S, Hill K, Burk R, Esaki N. Mammalian selenocysteine lyase is involved in selenoprotein biosynthesis. J Nutr Sci Vitaminol (Tokyo) 2012; 57:298-305. [PMID: 22041913 DOI: 10.3177/jnsv.57.298] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Selenocysteine lyase (SCL) catalyzes the decomposition of L-selenocysteine to yield L-alanine and selenium by acting exclusively on l-selenocysteine. The X-ray structural analysis of rat SCL has demonstrated how SCL discriminates L-selenocysteine from L-cysteine on the molecular basis. SCL has been proposed to function in the recycling of the micronutrient selenium from degraded selenoproteins containing selenocysteine residues, but the role of SCL in selenium metabolism in vivo remains unclear. We here demonstrate that the (75)Se-labeling efficiency of selenoproteins with (75)Se-labeled selenoprotein P (Sepp1) as a selenium source was decreased in HeLa cells transfected with SCL siRNA as compared to the cells transfected with control siRNA. Immunocytochemical analyses showed high SCL expression in kidney and liver cells, where selenocysteine is recovered from selenoproteins. Mature testes of mice exhibited a specific staining pattern of SCL in spermatids that actively produce selenoproteins. However, SCL was weakly expressed in Sertoli cells, which receive Sepp1 and supply selenium to germ cells. These demonstrate that SCL occurs in the cells requiring selenoproteins, probably to recycle selenium derived from selenoproteins such as Sepp1.
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Affiliation(s)
- Suguru Kurokawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
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38
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Johansson AL, Collins R, Arnér ESJ, Brzezinski P, Högbom M. Biochemical discrimination between selenium and sulfur 2: mechanistic investigation of the selenium specificity of human selenocysteine lyase. PLoS One 2012; 7:e30528. [PMID: 22291978 PMCID: PMC3266904 DOI: 10.1371/journal.pone.0030528] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 12/19/2011] [Indexed: 11/19/2022] Open
Abstract
Selenium is an essential trace element incorporated into selenoproteins as selenocysteine. Selenocysteine (Sec) lyases (SCLs) and cysteine (Cys) desulfurases (CDs) catalyze the removal of selenium or sulfur from Sec or Cys, respectively, and generally accept both substrates. Intriguingly, human SCL (hSCL) is specific for Sec even though the only difference between Sec and Cys is a single chalcogen atom. The crystal structure of hSCL was recently determined and gain-of-function protein variants that also could accept Cys as substrate were identified. To obtain mechanistic insight into the chemical basis for its substrate discrimination, we here report time-resolved spectroscopic studies comparing the reactions of the Sec-specific wild-type hSCL and the gain-of-function D146K/H389T variant, when given Cys as a substrate. The data are interpreted in light of other studies of SCL/CD enzymes and offer mechanistic insight into the function of the wild-type enzyme. Based on these results and previously available data we propose a reaction mechanism whereby the Sec over Cys specificity is achieved using a combination of chemical and physico-mechanical control mechanisms.
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Affiliation(s)
- Ann-Louise Johansson
- Arrhenius Laboratories for Natural Sciences C4, Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Ruairi Collins
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Elias S. J. Arnér
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Peter Brzezinski
- Arrhenius Laboratories for Natural Sciences C4, Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Martin Högbom
- Arrhenius Laboratories for Natural Sciences C4, Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
- * E-mail:
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39
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Collins R, Johansson AL, Karlberg T, Markova N, van den Berg S, Olesen K, Hammarström M, Flores A, Schüler H, Schiavone LH, Brzezinski P, Arnér ESJ, Högbom M. Biochemical discrimination between selenium and sulfur 1: a single residue provides selenium specificity to human selenocysteine lyase. PLoS One 2012; 7:e30581. [PMID: 22295093 PMCID: PMC3266270 DOI: 10.1371/journal.pone.0030581] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 12/19/2011] [Indexed: 11/24/2022] Open
Abstract
Selenium and sulfur are two closely related basic elements utilized in nature for a vast array of biochemical reactions. While toxic at higher concentrations, selenium is an essential trace element incorporated into selenoproteins as selenocysteine (Sec), the selenium analogue of cysteine (Cys). Sec lyases (SCLs) and Cys desulfurases (CDs) catalyze the removal of selenium or sulfur from Sec or Cys and generally act on both substrates. In contrast, human SCL (hSCL) is specific for Sec although the only difference between Sec and Cys is the identity of a single atom. The chemical basis of this selenium-over-sulfur discrimination is not understood. Here we describe the X-ray crystal structure of hSCL and identify Asp146 as the key residue that provides the Sec specificity. A D146K variant resulted in loss of Sec specificity and appearance of CD activity. A dynamic active site segment also provides the structural prerequisites for direct product delivery of selenide produced by Sec cleavage, thus avoiding release of reactive selenide species into the cell. We thus here define a molecular determinant for enzymatic specificity discrimination between a single selenium versus sulfur atom, elements with very similar chemical properties. Our findings thus provide molecular insights into a key level of control in human selenium and selenoprotein turnover and metabolism.
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Affiliation(s)
- Ruairi Collins
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Ann-Louise Johansson
- Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences C4, Stockholm University, Stockholm, Sweden
| | - Tobias Karlberg
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Natalia Markova
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Susanne van den Berg
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Kenneth Olesen
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Martin Hammarström
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Alex Flores
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Herwig Schüler
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Lovisa Holmberg Schiavone
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Peter Brzezinski
- Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences C4, Stockholm University, Stockholm, Sweden
| | - Elias S. J. Arnér
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Martin Högbom
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
- Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences C4, Stockholm University, Stockholm, Sweden
- * E-mail:
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40
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Hidese R, Mihara H, Esaki N. Bacterial cysteine desulfurases: versatile key players in biosynthetic pathways of sulfur-containing biofactors. Appl Microbiol Biotechnol 2011; 91:47-61. [DOI: 10.1007/s00253-011-3336-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Revised: 04/13/2011] [Accepted: 04/13/2011] [Indexed: 11/29/2022]
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41
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Heras IL, Palomo M, Madrid Y. Selenoproteins: the key factor in selenium essentiality. State of the art analytical techniques for selenoprotein studies. Anal Bioanal Chem 2011; 400:1717-27. [DOI: 10.1007/s00216-011-4916-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 03/10/2011] [Accepted: 03/14/2011] [Indexed: 01/25/2023]
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42
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Yoshimura T, Mihara H, Ohshima T, Tanizawa K. Kenji Soda--researching enzymes with the spirit of an alpinist. J Biochem 2011; 148:371-9. [PMID: 20924059 DOI: 10.1093/jb/mvq095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Like an alpinist continuously seeking virgin peaks to climb, Kenji Soda has investigated a variety of unique enzymes for which there was little or no information available; and by doing so he opened up a variety of new fields in enzyme science and technology. In particular, he has promoted the study of enzymes requiring vitamin B-derived cofactors such as FAD, NAD(P) and pyridoxal 5'-phosphate, shedding light on their reaction mechanisms, enzymological properties, crystal structures and potential practical applications. Highlighted in this review are the studies of enzymes acting on d-amino acids and sulphur/selenium-containing amino acids and those from thermophilic and psychrophilic bacteria.
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Affiliation(s)
- Toru Yoshimura
- Department of Applied Molecular Bioscience, Graduate School of Bioagricultural Sciences, Nagoya University, Aichi, Japan
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43
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Omi R, Kurokawa S, Mihara H, Hayashi H, Goto M, Miyahara I, Kurihara T, Hirotsu K, Esaki N. Reaction mechanism and molecular basis for selenium/sulfur discrimination of selenocysteine lyase. J Biol Chem 2010; 285:12133-9. [PMID: 20164179 DOI: 10.1074/jbc.m109.084475] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Selenocysteine lyase (SCL) catalyzes the pyridoxal 5'-phosphate-dependent removal of selenium from l-selenocysteine to yield l-alanine. The enzyme is proposed to function in the recycling of the micronutrient selenium from degraded selenoproteins containing selenocysteine residue as an essential component. The enzyme exhibits strict substrate specificity toward l-selenocysteine and no activity to its cognate l-cysteine. However, it remains unclear how the enzyme distinguishes between selenocysteine and cysteine. Here, we present mechanistic studies of selenocysteine lyase from rat. ESI-MS analysis of wild-type and C375A mutant SCL revealed that the catalytic reaction proceeds via the formation of an enzyme-bound selenopersulfide intermediate on the catalytically essential Cys-375 residue. UV-visible spectrum analysis and the crystal structure of SCL complexed with l-cysteine demonstrated that the enzyme reversibly forms a nonproductive adduct with l-cysteine. Cys-375 on the flexible loop directed l-selenocysteine, but not l-cysteine, to the correct position and orientation in the active site to initiate the catalytic reaction. These findings provide, for the first time, the basis for understanding how trace amounts of a selenium-containing substrate is distinguished from excessive amounts of its cognate sulfur-containing compound in a biological system.
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Affiliation(s)
- Rie Omi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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44
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Akbulut M, Cakir S. The effects of Se phytotoxicity on the antioxidant systems of leaf tissues in barley (Hordeum vulgare L.) seedlings. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2010; 48:160-6. [PMID: 19948409 DOI: 10.1016/j.plaphy.2009.11.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 11/01/2009] [Accepted: 11/09/2009] [Indexed: 05/07/2023]
Abstract
A hydroponic experiment was carried out in a growth chamber to investigate the impact of Selenium (Se) levels on physiological and biochemical characteristics of a barley cultivar. Membrane lipid peroxidation (LPO), proline accumulation and antioxidant activities of some enzymes of barley seedlings under Se toxicity were investigated. Significant increase in thiobarbituric acid reactive substance (TBARS) content, and a stimulation of catalase (CAT, 1.11.1.6), ascorbate peroxidase (APX, 1.11.1.11), glutathione reductase (GR, 1.6.4.2), and glutathione S-transferase (GST, 2.5.1.18) activities were recorded in barley seedlings subjected to 2, 4, 8, 16 ppm Se. Superoxide dismutase (SOD, EC 1.15.1.1) activity was not altered significantly. Plant height and chlorophyll content of the seedlings were also affected significantly in a dose dependent manner by Se treatment. Considerable amount of proline accumulation was also observed in response to Se treatment. The results indicated that increases in the activities of the antioxidant enzymes were not sufficient to protect cell membrane against Se toxicity.
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Affiliation(s)
- Mikail Akbulut
- Erciyes University, Faculty of Sciences and Arts, Department of Biology, Kayseri, Turkey.
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45
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Abstract
Yeast two-hybrid screening of mouse cDNA libraries was performed to identify proteins interacting with selenocysteine lyase (SCL), which decomposes L-selenocysteine. Several proteins related to spermatogenesis, protein synthesis, and cell viability/apoptosis were identified as potential interactors. Major urinary proteins 1 and 2 interacted with SCL and inhibited its activity. Coimmunoprecipitation revealed interactions between SCL and each of two selenophosphate synthetase isozymes.
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46
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Selenium, a Key Element in Spermatogenesis and Male Fertility. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 636:65-73. [DOI: 10.1007/978-0-387-09597-4_4] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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47
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Olson GE, Winfrey VP, Nagdas SK, Hill KE, Burk RF. Apolipoprotein E Receptor-2 (ApoER2) Mediates Selenium Uptake from Selenoprotein P by the Mouse Testis. J Biol Chem 2007; 282:12290-7. [PMID: 17314095 DOI: 10.1074/jbc.m611403200] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Selenium is a micronutrient that is essential for the production of normal spermatozoa. The selenium-rich plasma protein selenoprotein P (Sepp1) is required for maintenance of testis selenium and for fertility of the male mouse. Sepp1 trafficking in the seminiferous epithelium was studied using conventional methods and mice with gene deletions. Immunocytochemistry demonstrated that Sepp1 is present in vesicle-like structures in the basal region of Sertoli cells, suggesting that the protein is taken up intact. Sepp1 affinity chromatography of a testicular extract followed by mass spectrometry-based identification of bound proteins identified apolipoprotein E receptor 2 (ApoER2) as a candidate testis Sepp1 receptor. In situ hybridization analysis identified Sertoli cells as the only cell type in the seminiferous epithelium with detectable ApoER2 expression. Testis selenium levels in apoER2(-/-) males were sharply reduced from those in apoER2(+/+) males and were comparable with the depressed levels found in Sepp1(-/-) males. However, liver selenium levels were unchanged by deletion of apoER2. Immunocytochemistry did not detect Sepp1 in the Sertoli cells of apoER2(-/-) males, consistent with a defect in the receptor-mediated Sepp1 uptake pathway. Phase contrast microscopy revealed identical sperm defects in apoER2(-/-) and Sepp1(-/-) mice. Co-immunoprecipitation analysis demonstrated an interaction of testis ApoER2 with Sepp1. These data demonstrate that Sertoli cell ApoER2 is a Sepp1 receptor and a component of the selenium delivery pathway to spermatogenic cells.
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Affiliation(s)
- Gary E Olson
- Department of Cell and Developmental Biology, Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA.
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48
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Tarze A, Dauplais M, Grigoras I, Lazard M, Ha-Duong NT, Barbier F, Blanquet S, Plateau P. Extracellular Production of Hydrogen Selenide Accounts for Thiol-assisted Toxicity of Selenite against Saccharomyces cerevisiae. J Biol Chem 2007; 282:8759-67. [PMID: 17261587 DOI: 10.1074/jbc.m610078200] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Administration of selenium in humans has anticarcinogenic effects. However, the boundary between cancer-protecting and toxic levels of selenium is extremely narrow. The mechanisms of selenium toxicity need to be fully understood. In Saccharomyces cerevisiae, selenite in the millimolar range is well tolerated by cells. Here we show that the lethal dose of selenite is reduced to the micromolar range by the presence of thiols in the growth medium. Glutathione and selenite spontaneously react to produce several selenium-containing compounds (selenodiglutathione, glutathioselenol, hydrogen selenide, and elemental selenium) as well as reactive oxygen species. We studied which compounds in the reaction pathway between glutathione and sodium selenite are responsible for this toxicity. Involvement of selenodiglutathione, elemental selenium, or reactive oxygen species could be ruled out. In contrast, extracellular formation of hydrogen selenide can fully explain the exacerbation of selenite toxicity by thiols. Indeed, direct production of hydrogen selenide with D-cysteine desulfhydrase induces high mortality. Selenium uptake by S. cerevisiae is considerably enhanced in the presence of external thiols, most likely through internalization of hydrogen selenide. Finally, we discuss the possibility that selenium exerts its toxicity through consumption of intracellular reduced glutathione, thus leading to severe oxidative stress.
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Affiliation(s)
- Agathe Tarze
- Laboratoire de Biochimie, UMR CNRS 7654, Département de Biologie, Ecole Polytechnique, 91128 Palaiseau Cedex, France
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49
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Abstract
Recent identification of new selenocysteine-containing proteins has revealed relationships between the two trace elements selenium (Se) and iodine and the hormone network. Several selenoproteins participate in the protection of thyrocytes from damage by H(2)O(2) produced for thyroid hormone biosynthesis. Iodothyronine deiodinases are selenoproteins contributing to systemic or local thyroid hormone homeostasis. The Se content in endocrine tissues (thyroid, adrenals, pituitary, testes, ovary) is higher than in many other organs. Nutritional Se depletion results in retention, whereas Se repletion is followed by a rapid accumulation of Se in endocrine tissues, reproductive organs, and the brain. Selenoproteins such as thioredoxin reductases constitute the link between the Se metabolism and the regulation of transcription by redox sensitive ligand-modulated nuclear hormone receptors. Hormones and growth factors regulate the expression of selenoproteins and, conversely, Se supply modulates hormone actions. Selenoproteins are involved in bone metabolism as well as functions of the endocrine pancreas and adrenal glands. Furthermore, spermatogenesis depends on adequate Se supply, whereas Se excess may impair ovarian function. Comparative analysis of the genomes of several life forms reveals that higher mammals contain a limited number of identical genes encoding newly detected selenocysteine-containing proteins.
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Affiliation(s)
- J Köhrle
- Institut für Experimentelle Endokrinologie, Charité, Humboldt Universität zu Berlin, Schumannstrasse 20/21, D-10098 Berlin, Germany.
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50
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Schweizer U, Streckfuss F, Pelt P, Carlson BA, Hatfield DL, Köhrle J, Schomburg L. Hepatically derived selenoprotein P is a key factor for kidney but not for brain selenium supply. Biochem J 2005; 386:221-6. [PMID: 15638810 PMCID: PMC1134785 DOI: 10.1042/bj20041973] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Liver-specific inactivation of Trsp, the gene for selenocysteine tRNA, removes SePP (selenoprotein P) from plasma, causing serum selenium levels to fall from 298 microg/l to 50 microg/l and kidney selenium to decrease to 36% of wild-type levels. Likewise, glutathione peroxidase activities decreased in plasma and kidney to 43% and 18% respectively of wild-type levels. This agrees nicely with data from SePP knockout mice, supporting a selenium transport role for hepatically expressed SePP. However, brain selenium levels remain unaffected and neurological defects do not occur in the liver-specific Trsp knockout mice, while SePP knockout mice suffer from neurological defects. This indicates that a transport function in plasma is exerted by hepatically derived SePP, while in brain SePP fulfils a second, hitherto unexpected, essential role.
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Affiliation(s)
- Ulrich Schweizer
- Neurobiologie des Selens, Neurowissenschaftliches Forschungszentrum, Charité-Universitätsmedizin Berlin, Schumannstrasse 20/21, 10117 Berlin, Germany.
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