1
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Iwasaki H, Suwanai H, Yakou F, Sakai H, Ishii K, Hara N, Buckle AM, Kanekura K, Miyagi T, Narumi S, Suzuki R. Disulfide Bonds of Thyroid Peroxidase Are Critical Elements for Subcellular Localization, Proteasome-Dependent Degradation, and Enzyme Activity. Thyroid 2024; 34:659-667. [PMID: 38482822 DOI: 10.1089/thy.2023.0514] [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] [Indexed: 04/13/2024]
Abstract
Background: Congenital hypothyroidism (CH) is caused by mutations in cysteine residues, including Cys655 and Cys825 that form disulfide bonds in thyroid peroxidase (TPO). It is highly likely that these disulfide bonds could play an important role in TPO activity. However, to date, no study has comprehensively analyzed cysteine mutations that form disulfide bonds in TPO. In this study, we induced mutations in cysteine residues involved in disulfide bonds formation and analyzed their effect on subcellular localization, degradation, and enzyme activities to evaluate the importance of disulfide bonds in TPO activity. Methods: Vector plasmid TPO mutants, C655F and C825R, known to occur in CH, were transfected into HEK293 cells. TPO activity and protein expression levels were measured by the Amplex red assay and Western blotting. The same procedure was performed in the presence of MG132 proteasome inhibitor. Subcellular localization was determined using immunocytochemistry and flow cytometry. The locations of all disulfide bonds within TPO were predicted using in silico analysis. All TPO mutations associated with disulfide bonds were induced. TPO activity and protein expression levels were also measured in all TPO mutants associated with disulfide bonds using the Amplex red assay and Western blotting. Results: C655F and C825R showed significantly decreased activity and protein expression compared with the wild type (WT) (p < 0.05). In the presence of the MG132 proteasome inhibitor, the protein expression level of TPO increased to a level comparable with that of the WT without increases in its activity. The degree of subcellular distribution of TPO to the cell surface in the mutants was lower compared with the WT TPO. Twenty-four cysteine residues were involved in the formation of 12 disulfide bonds in TPO. All TPO mutants harboring an amino acid substitution in each cysteine showed significantly reduced TPO activity and protein expression levels. Furthermore, the differences in TPO activity depended on the position of the disulfide bond. Conclusions: All 12 disulfide bonds play an important role in the activity of TPO. Furthermore, the mutations lead to misfolding, degradation, and membrane insertion.
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Affiliation(s)
- Hajime Iwasaki
- Department of Diabetes, Metabolism, and Endocrinology, Tokyo Medical University, Tokyo, Japan
| | - Hirotsugu Suwanai
- Department of Diabetes, Metabolism, and Endocrinology, Tokyo Medical University, Tokyo, Japan
| | - Fumiyoshi Yakou
- Department of Diabetes, Metabolism, and Endocrinology, Tokyo Medical University, Tokyo, Japan
| | - Hiroyuki Sakai
- Department of Diabetes, Metabolism, and Endocrinology, Tokyo Medical University, Tokyo, Japan
| | - Keitaro Ishii
- Department of Diabetes, Metabolism, and Endocrinology, Tokyo Medical University, Tokyo, Japan
| | - Natsuko Hara
- Department of Diabetes, Metabolism, and Endocrinology, Tokyo Medical University, Tokyo, Japan
| | - Ashley M Buckle
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Kohsuke Kanekura
- Department of Pharmacology, Tokyo Medical University, Tokyo, Japan
| | - Tamami Miyagi
- Department of Pharmacology, Tokyo Medical University, Tokyo, Japan
| | - Satoshi Narumi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Ryo Suzuki
- Department of Diabetes, Metabolism, and Endocrinology, Tokyo Medical University, Tokyo, Japan
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Williams DE, Le SN, Hoke DE, Chandler PG, Gora M, Godlewska M, Banga JP, Buckle AM. Structural Studies of Thyroid Peroxidase Show the Monomer Interacting With Autoantibodies in Thyroid Autoimmune Disease. Endocrinology 2020; 161:5727781. [PMID: 32022847 DOI: 10.1210/endocr/bqaa016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/04/2020] [Indexed: 01/17/2023]
Abstract
Thyroid peroxidase (TPO) is a critical membrane-bound enzyme involved in the biosynthesis of multiple thyroid hormones, and is a major autoantigen in autoimmune thyroid diseases such as destructive (Hashimoto) thyroiditis. Here we report the biophysical and structural characterization of a novel TPO construct containing only the ectodomain of TPO and lacking the propeptide. The construct was enzymatically active and able to bind the patient-derived TR1.9 autoantibody. Analytical ultracentrifugation data suggest that TPO can exist as both a monomer and a dimer. Combined with negative stain electron microscopy and molecular dynamics simulations, these data show that the TR1.9 autoantibody preferentially binds the TPO monomer, revealing conformational changes that bring together previously disparate residues into a continuous epitope. In addition to providing plausible structural models of a TPO-autoantibody complex, this study provides validated TPO constructs that will facilitate further characterization, and advances our understanding of the structural, functional, and antigenic characteristics of TPO, an autoantigen implicated in some of the most common autoimmune diseases.
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Affiliation(s)
- Daniel E Williams
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Sarah N Le
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts
| | - David E Hoke
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Peter G Chandler
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Monika Gora
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Marlena Godlewska
- Department of Biochemistry and Molecular Biology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - J Paul Banga
- Emeritus, King's College London, London WC2R 2LS, United Kingdom
| | - Ashley M Buckle
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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Godlewska M, Banga PJ. Thyroid peroxidase as a dual active site enzyme: Focus on biosynthesis, hormonogenesis and thyroid disorders of autoimmunity and cancer. Biochimie 2019; 160:34-45. [DOI: 10.1016/j.biochi.2019.02.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 02/05/2019] [Indexed: 01/02/2023]
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Dong J, Cong Z, You M, Fu Y, Wang Y, Wang Y, Fu H, Wei L, Chen J. Effects of perinatal di (2-ethylhexyl) phthalate exposure on thyroid function in rat offspring. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2019; 67:53-60. [PMID: 30716676 DOI: 10.1016/j.etap.2019.01.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/14/2018] [Accepted: 01/23/2019] [Indexed: 06/09/2023]
Abstract
Di (2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer in industry and displays the characteristics of an endocrine disruptor. Disorders of the maternal thyroid hormone (TH) during pregnancy can cause adverse effects on the fetus. We investigated the effects and possible mechanism of perinatal DEHP exposure on the thyroid function of pups. Pregnant female Wistar rats were randomly divided into four groups and received doses of DEHP of 0, 30, 300, 750 mg/kg/day by gavage at from gestational day (GD) 0 to postnatal day (PN) 21. The concentration of serum THs and the ultrastructure of thyroid follicular cells in the offspring were examined. Related protein level and gene expression of thyroid proteins in pups were analyzed by western blotting and real-time PCR. We found that DEHP significantly reduced total thyroxine (TT4) and increased thyroid stimulating hormone (TSH) in pups, while total triiodothyronine (TT3) showed no change. Thyroid follicular cells ultrastructure was damaged in DEHP exposed pups as viewed by electron microscopy. Furthermore, exposure to DEHP significantly increased protein and mRNA levels of thyroid transcription factor 1 (TTF-1), paired box 8 (PAX8), sodium iodide symporter (NIS) and thyroid peroxidase (TPO) in pups. In addition, levels of deiodinases of pups were also affected. These findings indicated that DEHP can disrupt thyroid function by damaging thyroid follicles and affecting TTF-1, PAX8, NIS, TPO and the deiodinase protein family.
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Affiliation(s)
- Jing Dong
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang 110122, People's Republic of China
| | - Zhangzhao Cong
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang 110122, People's Republic of China
| | - Mingdan You
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang 110122, People's Republic of China
| | - Yuanyuan Fu
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang 110122, People's Republic of China
| | - Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang 110122, People's Republic of China
| | - Yuan Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang 110122, People's Republic of China
| | - Hui Fu
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang 110122, People's Republic of China
| | - Lingling Wei
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang 110122, People's Republic of China
| | - Jie Chen
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang 110122, People's Republic of China.
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Cole M, Hynes AM, Howel D, Hall L, Abinun M, Allahabadia A, Barrett T, Boelaert K, Drake AJ, Dimitri P, Kirk J, Zammitt N, Pearce S, Cheetham T. Adjuvant rituximab, a potential treatment for the young patient with Graves' hyperthyroidism (RiGD): study protocol for a single-arm, single-stage, phase II trial. BMJ Open 2019; 9:e024705. [PMID: 30670519 PMCID: PMC6347892 DOI: 10.1136/bmjopen-2018-024705] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 09/25/2018] [Accepted: 11/22/2018] [Indexed: 12/11/2022] Open
Abstract
INTRODUCTION Graves' disease (Graves' hyperthyroidism) is a challenging condition for the young person and their family. The excess thyroid hormone generated by autoimmune stimulation of the thyroid stimulating hormone receptor on the thyroid gland can have a profound impact on well-being. Managing the young person with Graves' hyperthyroidism is more difficult than in older people because the side effects of conventional treatment are more significant in this age group and because the disease tends not to resolve spontaneously in the short to medium term. New immunomodulatory agents are available and the anti-B cell monoclonal antibody rituximab is of particular interest because it targets cells that manufacture the antibodies that stimulate the thyroid gland in Graves'. METHODS AND ANALYSIS The trial aims to establish whether the combination of a single dose of rituximab (500 mg) and a 12-month course of antithyroid drug (usually carbimazole) can result in a meaningful increase in the proportion of patients in remission at 2 years, the primary endpoint. A single-stage, phase II A'Hern design is used. 27 patients aged 12-20 years with newly presenting Graves' hyperthyroidism will be recruited. Markers of immune function, including lymphocyte numbers and antibody levels (total and specific), will be collected regularly throughout the trial. DISCUSSION The trial will determine whether the immunomodulatory medication, rituximab, will facilitate remission above and beyond that observed with antithyroid drug alone. A meaningful increase in the expected proportion of young patients entering remission when managed according to the trial protocol will justify consideration of a phase III trial.Ethics and dissemination The trial has received a favourable ethical opinion (North East - Tyne and Wear South Research Ethics Committee, reference 16/NE/0253, EudraCT number 2016-000209-35). The results of this trial will be distributed at international endocrine meetings, in the peer-reviewed literature and via patient support groups. TRIAL REGISTRATION NUMBER ISRCTN20381716.
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Affiliation(s)
- Michael Cole
- Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UK
| | - Ann Marie Hynes
- Newcastle Clinical Trials Unit, Newcastle University, Newcastle upon Tyne, UK
| | - Denise Howel
- Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UK
| | - Lesley Hall
- Newcastle Clinical Trials Unit, Newcastle University, Newcastle upon Tyne, UK
| | - Mario Abinun
- Institute of Cellular Medicine, Newcastle University, Great North Children’s Hospital, Newcastle upon Tyne, UK
| | - Amit Allahabadia
- Academic Directorate of Diabetes and Endocrinology, Royal Hallamshire Hospital, Sheffield, UK
| | - Timothy Barrett
- C/O Diabetes Unit, Birmingham Children’s Hospital, Birmingham, UK
| | - Kristien Boelaert
- Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham, UK
| | - Amanda J Drake
- Centre for Cardiovascular Science, Queen’s Medical Research Institute, Edinburgh, UK
| | - Paul Dimitri
- The Academic Unit of Child Health, Sheffield Children’s NHS Trust Western Bank, Sheffield, UK
| | - Jeremy Kirk
- Department of Endocrine, Birmingham Children’s Hospital, Birmingham, UK
| | - Nicola Zammitt
- Edinburgh Centre for Endocrinology and Diabetes, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - Simon Pearce
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Tim Cheetham
- Department of Paediatric Endocrinology, Institute of Genetic Medicine, Newcastle University, Great North Children’s Hospital, Newcastle upon Tyne, UK
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Mondal S, Raja K, Schweizer U, Mugesh G. Chemie und Biologie der Schilddrüsenhormon-Biosynthese und -Wirkung. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601116] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Santanu Mondal
- Department of Inorganic and Physical Chemistry; Indian Institute of Science; Bangalore Indien
| | - Karuppusamy Raja
- Department of Inorganic and Physical Chemistry; Indian Institute of Science; Bangalore Indien
| | - Ulrich Schweizer
- Rheinische Friedrich-Wilhelms-Universität Bonn; Institut für Biochemie und Molekularbiologie; Nussallee 11 53115 Bonn Deutschland
| | - Govindasamy Mugesh
- Department of Inorganic and Physical Chemistry; Indian Institute of Science; Bangalore Indien
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Mondal S, Raja K, Schweizer U, Mugesh G. Chemistry and Biology in the Biosynthesis and Action of Thyroid Hormones. Angew Chem Int Ed Engl 2016; 55:7606-30. [DOI: 10.1002/anie.201601116] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Santanu Mondal
- Department of Inorganic and Physical Chemistry; Indian Institute of Science; Bangalore India
| | - Karuppusamy Raja
- Department of Inorganic and Physical Chemistry; Indian Institute of Science; Bangalore India
| | - Ulrich Schweizer
- Rheinische Friedrich-Wilhelms-Universität Bonn; Institut für Biochemie und Molekularbiologie; Nussallee 11 53115 Bonn Germany
| | - Govindasamy Mugesh
- Department of Inorganic and Physical Chemistry; Indian Institute of Science; Bangalore India
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Le SN, Porebski BT, McCoey J, Fodor J, Riley B, Godlewska M, Góra M, Czarnocka B, Banga JP, Hoke DE, Kass I, Buckle AM. Modelling of Thyroid Peroxidase Reveals Insights into Its Enzyme Function and Autoantigenicity. PLoS One 2015; 10:e0142615. [PMID: 26623656 PMCID: PMC4666655 DOI: 10.1371/journal.pone.0142615] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 10/23/2015] [Indexed: 11/18/2022] Open
Abstract
Thyroid peroxidase (TPO) catalyses the biosynthesis of thyroid hormones and is a major autoantigen in Hashimoto's disease--the most common organ-specific autoimmune disease. Epitope mapping studies have shown that the autoimmune response to TPO is directed mainly at two surface regions on the molecule: immunodominant regions A and B (IDR-A, and IDR-B). TPO has been a major target for structural studies for over 20 years; however, to date, the structure of TPO remains to be determined. We have used a molecular modelling approach to investigate plausible modes of TPO structure and dimer organisation. Sequence features of the C-terminus are consistent with a coiled-coil dimerization motif that most likely anchors the TPO dimer in the apical membrane of thyroid follicular cells. Two contrasting models of TPO were produced, differing in the orientation and exposure of their active sites relative to the membrane. Both models are equally plausible based upon the known enzymatic function of TPO. The "trans" model places IDR-B on the membrane-facing side of the myeloperoxidase (MPO)-like domain, potentially hindering access of autoantibodies, necessitating considerable conformational change, and perhaps even dissociation of the dimer into monomers. IDR-A spans MPO- and CCP-like domains and is relatively fragmented compared to IDR-B, therefore most likely requiring domain rearrangements in order to coalesce into one compact epitope. Less epitope fragmentation and higher solvent accessibility of the "cis" model favours it slightly over the "trans" model. Here, IDR-B clusters towards the surface of the MPO-like domain facing the thyroid follicular lumen preventing steric hindrance of autoantibodies. However, conformational rearrangements may still be necessary to allow full engagement with autoantibodies, with IDR-B on both models being close to the dimer interface. Taken together, the modelling highlights the need to consider the oligomeric state of TPO, its conformational properties, and its proximity to the membrane, when interpreting epitope-mapping data.
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Affiliation(s)
- Sarah N. Le
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Benjamin T. Porebski
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Julia McCoey
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - James Fodor
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Blake Riley
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Marlena Godlewska
- The Centre of Postgraduate Medical Education, Department of Biochemistry and Molecular Biology, Warsaw, Poland
| | - Monika Góra
- Institute of Biochemistry and Biophysics PAS, Department of Genetics, Warsaw, Poland
| | - Barbara Czarnocka
- The Centre of Postgraduate Medical Education, Department of Biochemistry and Molecular Biology, Warsaw, Poland
| | - J Paul Banga
- King's College London School of Medicine, Division of Diabetes and Nutrition Sciences, London, United Kingdom
| | - David E. Hoke
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Itamar Kass
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- * E-mail: (AMB); (IK)
| | - Ashley M. Buckle
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- * E-mail: (AMB); (IK)
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Functional analyses of C.2268dup in thyroid peroxidase gene associated with goitrous congenital hypothyroidism. BIOMED RESEARCH INTERNATIONAL 2014; 2014:370538. [PMID: 24745015 PMCID: PMC3976875 DOI: 10.1155/2014/370538] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 01/23/2014] [Accepted: 02/06/2014] [Indexed: 11/17/2022]
Abstract
The c.2268dup mutation in thyroid peroxidase (TPO) gene was reported to be a founder mutation in Taiwanese patients with dyshormonogenetic congenital hypothyroidism (CH). The functional impact of the mutation is not well documented. In this study, homozygous c.2268dup mutation was detected in two Malaysian-Chinese sisters with goitrous CH. Normal and alternatively spliced TPO mRNA transcripts were present in thyroid tissues of the two sisters. The abnormal transcript contained 34 nucleotides originating from intron 12. The c.2268dup is predicted to generate a premature termination codon (PTC) at position 757 (p.Glu757X). Instead of restoring the normal reading frame, the alternatively spliced transcript has led to another stop codon at position 740 (p.Asp739ValfsX740). The two PTCs are located at 116 and 201 nucleotides upstream of the exons 13/14 junction fulfilling the requirement for a nonsense-mediated mRNA decay (NMD). Quantitative RT-PCR revealed an abundance of unidentified transcripts believed to be associated with the NMD. TPO enzyme activity was not detected in both patients, even though a faint TPO band of about 80 kD was present. In conclusion, the c.2268dup mutation leads to the formation of normal and alternatively spliced TPO mRNA transcripts with a consequential loss of TPO enzymatic activity in Malaysian-Chinese patients with goitrous CH.
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Klatka M, Grywalska E, Partyka M, Charytanowicz M, Kiszczak-Bochynska E, Rolinski J. Th17 and Treg cells in adolescents with Graves’ disease. Impact of treatment with methimazole on these cell subsets. Autoimmunity 2014; 47:201-11. [DOI: 10.3109/08916934.2013.879862] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Maria Klatka
- Department of Pediatric Endocrinology and Diabetology, Medical University of Lublin
LublinPoland
| | - Ewelina Grywalska
- Department of Clinical Immunology and Immunotherapy, Medical University of Lublin
LublinPoland
| | - Malgorzata Partyka
- Department of Jaw Orthopedics, Medical University of Lublin
LublinPoland
| | - Malgorzata Charytanowicz
- Institute of Mathematics and Computer Science, The John Paul II Catholic University
LublinPoland
| | | | - Jacek Rolinski
- Department of Clinical Immunology and Immunotherapy, Medical University of Lublin
LublinPoland
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Purtell K, Paroder-Belenitsky M, Reyna-Neyra A, Nicola JP, Koba W, Fine E, Carrasco N, Abbott GW. The KCNQ1-KCNE2 K⁺ channel is required for adequate thyroid I⁻ uptake. FASEB J 2012; 26:3252-9. [PMID: 22549510 DOI: 10.1096/fj.12-206110] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The KCNQ1 α subunit and the KCNE2 β subunit form a potassium channel in thyroid epithelial cells. Genetic disruption of KCNQ1-KCNE2 causes hypothyroidism in mice, resulting in cardiac hypertrophy, dwarfism, alopecia, and prenatal mortality. Here, we investigated the mechanistic requirement for KCNQ1-KCNE2 in thyroid hormone biosynthesis, utilizing whole-animal dynamic positron emission tomography. The KCNQ1-specific antagonist (-)-[3R,4S]-chromanol 293B (C293B) significantly impaired thyroid cell I(-) uptake, which is mediated by the Na(+)/I(-) symporter (NIS), in vivo (dSUV/dt: vehicle, 0.028 ± 0.004 min(-1); 10 mg/kg C293B, 0.009 ± 0.006 min(-1)) and in vitro (EC(50): 99 ± 10 μM C293B). Na(+)-dependent nicotinate uptake by SMCT, however, was unaffected. Kcne2 deletion did not alter the balance of free vs. thyroglobulin-bound I(-) in the thyroid (distinguished using ClO(4)(-), a competitive inhibitor of NIS), indicating that KCNQ1-KCNE2 is not required for Duox/TPO-mediated I(-) organification. However, Kcne2 deletion doubled the rate of free I(-) efflux from the thyroid following ClO(4)(-) injection, a NIS-independent process. Thus, KCNQ1-KCNE2 is necessary for adequate thyroid cell I(-) uptake, the most likely explanation being that it is prerequisite for adequate NIS activity.
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Affiliation(s)
- Kerry Purtell
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, USA
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12
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Song M, Kim YJ, Park YK, Ryu JC. Changes in thyroid peroxidase activity in response to various chemicals. ACTA ACUST UNITED AC 2012; 14:2121-6. [DOI: 10.1039/c2em30106g] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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13
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Song M, Kim YJ, Song MK, Choi HS, Park YK, Ryu JC. Identification of classifiers for increase or decrease of thyroid peroxidase activity in the FTC-238/hTPO recombinant cell line. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:7906-14. [PMID: 21809831 DOI: 10.1021/es200475k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Thyroid peroxidase (TPO) plays an important role in thyroid hormone biosynthesis, as it catalyzes all of the essential steps in iodide organification. TPO activity can be detected using the guaiacol assay; however, this assay is complex and very time-consuming. Therefore, we focused on devising a simplified method using microarrays to detect changes in TPO activity, which is a target for disruption of the thyroid hormone axis. These experiments have systematically assessed the potential utility of transcriptomic end points as enhancements to the guaiacol assay. Previously, we demonstrated that benzophenone-2, benzophenone, perfluorooctane sulfonate, bisphenol A bis ether, and vinclozolin decreased TPO activity, and that dibutyl phthalate, carbaryl, dibenzo(a,h)anthracene, benzo(a)pyrene, and methylmercury increased TPO activity. In this work, we used human oligonucleotide chips to examine changes in the gene expression profile of FTC-238 human follicular thyroid carcinoma cells expressing human recombinant TPO, after exposure of the cells to TPO activity-disrupting agents. We identified 362 classifiers that could predict the effect of the toxicants on TPO activity with about 70% accuracy. These classifiers are potential markers for predicting the effects of chemicals on thyroid hormone production.
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Affiliation(s)
- Mee Song
- Cellular and Molecular Toxicology Laboratory, Korea Institute of Science and Technology (KIST), Republic of Korea
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14
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Lüthje S, Meisrimler CN, Hopff D, Möller B. Phylogeny, topology, structure and functions of membrane-bound class III peroxidases in vascular plants. PHYTOCHEMISTRY 2011; 72:1124-1135. [PMID: 21211808 DOI: 10.1016/j.phytochem.2010.11.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 11/17/2010] [Accepted: 11/25/2010] [Indexed: 05/30/2023]
Abstract
Peroxidases are key player in the detoxification of reactive oxygen species during cellular metabolism and oxidative stress. Membrane-bound isoenzymes have been described for peroxidase superfamilies in plants and animals. Recent studies demonstrated a location of peroxidases of the secretory pathway (class III peroxidases) at the tonoplast and the plasma membrane. Proteomic approaches using highly enriched plasma membrane preparations suggest organisation of these peroxidases in microdomains, a developmentally regulation and an induction of isoenzymes by oxidative stress. Phylogenetic relations, topology, putative structures, and physiological function of membrane-bound class III peroxidases will be discussed.
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Affiliation(s)
- Sabine Lüthje
- University of Hamburg, Biocenter Klein Flottbek, Dept. Plant Physiology, Ohnhorststrasse 18, 22609 Hamburg, Germany.
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