1
|
Bagga AD, Johnson BP, Zhang Q. Spatially Dependent Tissue Distribution of Thyroid Hormones by Plasma Thyroid Hormone Binding Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.20.572629. [PMID: 38187691 PMCID: PMC10769377 DOI: 10.1101/2023.12.20.572629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Plasma thyroid hormone (TH) binding proteins (THBPs), including thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin (ALB), carry THs to extrathyroidal sites, where THs are unloaded locally and then taken up via membrane transporters into the tissue proper. The respective roles of THBPs in supplying THs for tissue uptake are not completely understood. To investigate this, we developed a spatial human physiologically based kinetic (PBK) model of THs, which produces several novel findings. (1) Contrary to postulations that TTR and/or ALB are the major local T4 contributors, the three THBPs may unload comparable amounts of T4 in Liver, a rapidly perfused organ; however, their contributions in slowly perfused tissues follow the order of abundances of T4TBG, T4TTR, and T4ALB. The T3 amounts unloaded from or loaded onto THBPs in a tissue acting as a T3 sink or source respectively follow the order of abundance of T3TBG, T3ALB, and T3TTR regardless of perfusion rate. (2) Any THBP alone is sufficient to maintain spatially uniform TH tissue distributions. (3) The TH amounts unloaded by each THBP species are spatially dependent and nonlinear in a tissue, with ALB being the dominant contributor near the arterial end but conceding to TBG near the venous end. (4) Spatial gradients of TH transporters and metabolic enzymes may modulate these contributions, producing spatially invariant or heterogeneous TH tissue concentrations depending on whether the blood-tissue TH exchange operates in near-equilibrium mode. In summary, our modeling provides novel insights into the differential roles of THBPs in local TH tissue distribution.
Collapse
Affiliation(s)
- Anish D. Bagga
- Emory College of Arts and Sciences, Emory University, Atlanta, GA 30322, USA
| | - Brian P. Johnson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, GA 30322, USA
| |
Collapse
|
2
|
Bagga AD, Johnson BP, Zhang Q. A minimal human physiologically based kinetic model of thyroid hormones and chemical disruption of plasma thyroid hormone binding proteins. Front Endocrinol (Lausanne) 2023; 14:1168663. [PMID: 37305053 PMCID: PMC10248451 DOI: 10.3389/fendo.2023.1168663] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 05/11/2023] [Indexed: 06/13/2023] Open
Abstract
The thyroid hormones (THs), thyroxine (T4) and triiodothyronine (T3), are under homeostatic control by the hypothalamic-pituitary-thyroid axis and plasma TH binding proteins (THBPs), including thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin (ALB). THBPs buffer free THs against transient perturbations and distribute THs to tissues. TH binding to THBPs can be perturbed by structurally similar endocrine-disrupting chemicals (EDCs), yet their impact on circulating THs and health risks are unclear. In the present study, we constructed a human physiologically based kinetic (PBK) model of THs and explored the potential effects of THBP-binding EDCs. The model describes the production, distribution, and metabolism of T4 and T3 in the Body Blood, Thyroid, Liver, and Rest-of-Body (RB) compartments, with explicit consideration of the reversible binding between plasma THs and THBPs. Rigorously parameterized based on literature data, the model recapitulates key quantitative TH kinetic characteristics, including free, THBP-bound, and total T4 and T3 concentrations, TH productions, distributions, metabolisms, clearance, and half-lives. Moreover, the model produces several novel findings. (1) The blood-tissue TH exchanges are fast and nearly at equilibrium especially for T4, providing intrinsic robustness against local metabolic perturbations. (2) Tissue influx is limiting for transient tissue uptake of THs when THBPs are present. (3) Continuous exposure to THBP-binding EDCs does not alter the steady-state levels of THs, while intermittent daily exposure to rapidly metabolized TBG-binding EDCs can cause much greater disruptions to plasma and tissue THs. In summary, the PBK model provides novel insights into TH kinetics and the homeostatic roles of THBPs against thyroid disrupting chemicals.
Collapse
Affiliation(s)
- Anish D. Bagga
- Emory College of Arts and Sciences, Emory University, Atlanta, GA, United States
| | - Brian P. Johnson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, GA, Atlanta, United States
| |
Collapse
|
3
|
Yamauchi I, Sakane Y, Okuno Y, Sugawa T, Hakata T, Fujita H, Okamoto K, Taura D, Yamashita T, Hirota K, Ueda Y, Fujii T, Yasoda A, Inagaki N. High-throughput Screening in Combination With a Cohort Study for Iodothyronine Deiodinases. Endocrinology 2022; 163:6607576. [PMID: 35695766 DOI: 10.1210/endocr/bqac090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Indexed: 11/19/2022]
Abstract
Regulatory mechanisms of iodothyronine deiodinases (DIOs) require further elucidation, and conventional methods for evaluating DIOs are unsuitable for high-throughput screening (HTS). Here we explored factors of transcriptional regulation of 3 types of DIOs (DIO1, DIO2, and DIO3) from a chemical library using our designed HTS. We constructed HTS based on a promoter assay and performed a screen of 2480 bioactive compounds. For compounds that were clinically approved, we validated hit compounds through a retrospective cohort study in our department that evaluated changes in thyroid function in patients using the compounds as drug therapy. Furthermore, we verified the involvement of DIOs using mice treated with the compounds. Of the hit compounds, 6 and 7 compounds transcriptionally up- and downregulated DIO1, respectively; 34 transcriptionally upregulated DIO2; and 5 and 2 compounds transcriptionally up- and downregulated DIO3, respectively. The cohort study clarified the clinical effects of some hit compounds: ritodrine increased free triiodothyronine (fT3)/free thyroxine (fT4) ratio and decreased serum thyroid-stimulating hormone (TSH) levels, tadalafil increased serum fT3 levels, and tyrosine kinase inhibitors (TKIs) decreased serum fT3 and fT4 levels and increased serum TSH levels. Following in vivo experiments using treated mice, consistent results were observed in ritodrine, which upregulated DIO2 in the thyroid gland. In conclusion, we completed HTS for DIOs and obtained attractive hit compounds. Our cohort study revealed the clinical significance of ritodrine, sildenafil, and TKIs. We hope our unique method will contribute to analyzing various targets and lists of hit compounds will promote understanding of DIOs.
Collapse
Affiliation(s)
- Ichiro Yamauchi
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yoriko Sakane
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Sugawa Clinic, Kyoto, Japan
| | - Yukiko Okuno
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Taku Sugawa
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takuro Hakata
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Haruka Fujita
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kentaro Okamoto
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Daisuke Taura
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takafumi Yamashita
- Metabolism and Endocrinology Division of Internal Medicine, Kishiwada City Hospital, Osaka, Japan
| | - Keisho Hirota
- Department of Pathology and Biology of Diseases, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yohei Ueda
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Toshihito Fujii
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Akihiro Yasoda
- Clinical Research Center, National Hospital Organization Kyoto Medical Center, Kyoto, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| |
Collapse
|
4
|
Yamauchi I, Yamashita T, Sugawa T, Tagami T, Hanaoka I, Usui T, Hirota K, Hakata T, Ueda Y, Fujii T, Sakane Y, Yasoda A, Inagaki N. Bezafibrate induces hypothyroidism in a patient with resistance to thyroid hormone β due to a G347R variant. Clin Endocrinol (Oxf) 2022; 96:236-245. [PMID: 34519083 DOI: 10.1111/cen.14591] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 07/29/2021] [Accepted: 09/03/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVE A unique clinical course was observed in a patient with resistance to thyroid hormone β (RTHβ) caused by a variant of the THRB gene leading to the replacement of glycine with arginine in codon 347 (p.G347R). He presented with the syndrome of inappropriate secretion of thyrotropin (TSH) (free T4 [fT4]: 32.43 pmol/L, TSH: 4.67 mIU/L), but slowly developed progressive hypothyroidism (fT4: 8.37 pmol/L, TSH: 100.90 mIU/L) that resolved after suspending bezafibrate (BZ) treatment (fT4: 32.18 pmol/L, TSH: 7.14 mIU/L). This study clinically and experimentally evaluated this interesting phenomenon. METHODS A retrospective cohort analysis of non-RTHβ patients was performed at Kyoto University Hospital. Data before BZ treatment were compared to the first data after treatment. Using reporter assays of iodothyronine deiodinases (DIO1, DIO2, DIO3) in HEK293T cells, we performed functional analyses of mutant thyroid hormone receptor β with p.G347R (G347R TRβ). Mice with G347R TRβ were generated by hydrodynamic gene delivery. RESULTS In non-RTHβ patients (n = 7), BZ treatment did not change serum free T3 and TSH but significantly increased fT4 (p = .008). BZ administration increased DIO3 reporter activity in the context of G347R TRβ, whereas did not change DIO1 and DIO2 reporter activity. In the livers of mice with G347R TRβ, BZ administration increased reverse T3 content, which corresponded to an increase in Dio3 messenger RNA. CONCLUSIONS While hypothyroidism associated with BZ treatment did not occur in non-RTHβ patients, it was observed in a patient with RTHβ due to the p.G347R variant. Liver DIO3 upregulation might involve this hypothyroidism.
Collapse
Affiliation(s)
- Ichiro Yamauchi
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takafumi Yamashita
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Metabolism and Endocrinology Division of Internal Medicine, Kishiwada City Hospital, Osaka, Japan
| | - Taku Sugawa
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Endocrinology and Metabolism, National Hospital Organization Kyoto Medical Center, Kyoto, Japan
| | - Tetsuya Tagami
- Department of Endocrinology and Metabolism, National Hospital Organization Kyoto Medical Center, Kyoto, Japan
- Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto, Japan
| | - Ikuko Hanaoka
- Metabolism and Endocrinology Division of Internal Medicine, Kishiwada City Hospital, Osaka, Japan
| | - Takeshi Usui
- Department of Medical Genetics, Shizuoka General Hospital, Shizuoka, Japan
- Research Support Center, Shizuoka General Hospital, Shizuoka, Japan
| | - Keisho Hirota
- Department of Pathology and Biology of Diseases, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takuro Hakata
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yohei Ueda
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Toshihito Fujii
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yoriko Sakane
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Sugawa Clinic, Kyoto, Japan
| | - Akihiro Yasoda
- Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| |
Collapse
|
5
|
Jing L, Zhang Q. Intrathyroidal feedforward and feedback network regulating thyroid hormone synthesis and secretion. Front Endocrinol (Lausanne) 2022; 13:992883. [PMID: 36187113 PMCID: PMC9519864 DOI: 10.3389/fendo.2022.992883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022] Open
Abstract
Thyroid hormones (THs), including T4 and T3, are produced and released by the thyroid gland under the stimulation of thyroid-stimulating hormone (TSH). The homeostasis of THs is regulated via the coordination of the hypothalamic-pituitary-thyroid axis, plasma binding proteins, and local metabolism in tissues. TH synthesis and secretion in the thyrocytes-containing thyroid follicles are exquisitely regulated by an elaborate molecular network comprising enzymes, transporters, signal transduction machineries, and transcription factors. In this article, we synthesized the relevant literature, organized and dissected the complex intrathyroidal regulatory network into structures amenable to functional interpretation and systems-level modeling. Multiple intertwined feedforward and feedback motifs were identified and described, centering around the transcriptional and posttranslational regulations involved in TH synthesis and secretion, including those underpinning the Wolff-Chaikoff and Plummer effects and thyroglobulin-mediated feedback regulation. A more thorough characterization of the intrathyroidal network from a systems biology perspective, including its topology, constituent network motifs, and nonlinear quantitative properties, can help us to better understand and predict the thyroidal dynamics in response to physiological signals, therapeutic interventions, and environmental disruptions.
Collapse
Affiliation(s)
- Li Jing
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, China
- *Correspondence: Li Jing, ; Qiang Zhang,
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, United States
- *Correspondence: Li Jing, ; Qiang Zhang,
| |
Collapse
|
6
|
Comarella AP, Vilagellin D, Bufalo NE, Euflauzino JF, de Souza Teixeira E, Miklos ABPP, Dos Santos RB, Romaldini JH, Ward LS. The polymorphic inheritance of DIO2 rs225014 may predict body weight variation after Graves' disease treatment. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2021; 64:787-795. [PMID: 33049131 PMCID: PMC10528618 DOI: 10.20945/2359-3997000000295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 07/13/2020] [Indexed: 11/23/2022]
Abstract
OBJECTIVE We aimed to investigate the role of DIO2 polymorphisms rs225014 and rs12885300 in Graves' disease patients, mainly for controlling body weight following treatment. METHODS We genotyped 280 GD patients by the time of diagnosis and 297 healthy control individuals using a TaqMan SNP Genotyping technique. We followed up 141 patients for 18.94 ± 6.59 months after treatment. RESULTS There was no relationship between the investigated polymorphisms with susceptibility to GD and gain or loss of weight after GD treatment. However, the polymorphic inheritance (CC+CT genotype) of DIO2 rs225014 was associated with a lower body weight variation after GD treatment (4.26 ± 6.25 kg) when compared to wild type TT genotype (6.34 ± 7.26 kg; p = 0.0456 adjusted for the follow-up time). This data was confirmed by a multivariate analysis (p = 0.0138) along with a longer follow-up period (p = 0.0228), older age (p = 0.0306), treatment with radioiodine (p-value = 0.0080) and polymorphic inheritance of DIO2 rs12885300 (p = 0.0306). CONCLUSION We suggest that DIO2 rs225014 genotyping may have an auxiliary role in predicting the post-treatment weight behavior of GD patients.
Collapse
Affiliation(s)
- Ana Paula Comarella
- Laboratório de Genética Molecular do Câncer, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (Unicamp), Campinas, SP, Brasil,
| | - Danilo Vilagellin
- Endocrinologia e Metabolismo, Faculdade de Medicina, Pontifícia Universidade Católica de Campinas (PUC-Campinas), Campinas, SP, Brasil
| | - Natassia Elena Bufalo
- Laboratório de Genética Molecular do Câncer, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (Unicamp), Campinas, SP, Brasil
| | - Jessica Ferreira Euflauzino
- Endocrinologia e Metabolismo, Faculdade de Medicina, Pontifícia Universidade Católica de Campinas (PUC-Campinas), Campinas, SP, Brasil
| | - Elisangela de Souza Teixeira
- Laboratório de Genética Molecular do Câncer, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (Unicamp), Campinas, SP, Brasil
| | | | - Roberto Bernardo Dos Santos
- Endocrinologia e Metabolismo, Faculdade de Medicina, Pontifícia Universidade Católica de Campinas (PUC-Campinas), Campinas, SP, Brasil
| | - João H Romaldini
- Endocrinologia e Metabolismo, Faculdade de Medicina, Pontifícia Universidade Católica de Campinas (PUC-Campinas), Campinas, SP, Brasil
| | - Laura S Ward
- Laboratório de Genética Molecular do Câncer, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (Unicamp), Campinas, SP, Brasil
| |
Collapse
|
7
|
Tagami T. An overview of thyroid function tests in subjects with resistance to thyroid hormone and related disorders. Endocr J 2021; 68:509-517. [PMID: 33827995 DOI: 10.1507/endocrj.ej21-0059] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Confirmation of sustained syndrome of inappropriate secretion of thyrotropin (SITSH) is a milestone in diagnosis of β type of resistance to thyroid hormone (RTHβ). The differential diagnoses of RTHβ include TSH-producing pituitary adenoma (TSHoma) and familial dysalbuminemic hyperthyroxinemia (FDH), which also present SITSH. Recently, patients with RTHα caused by a mutation in thyroid hormone receptor α were reported and they did not present SITSH but a decline in the serum T4/T3 ratio. This review was aimed to overview thyroid function tests in RTH and related disorders. First, the characteristics of the thyroid function in RTHβ, TSHoma, and FDH obtained from a Japanese database are summarized. Second, the degrees of SITSH in patients with truncations and frameshifts were compared with those in patients with single amino acid deletions and single amino acid substitutions obtained from the literature. Third, the degrees of SITSH in homozygous patients were compared with those in heterozygous patients with cognate mutations. Finally, the FT3/FT4 ratios in RTHα are summarized. In principle, the TSH values in FDH were within the normal range and apparent FT4 values in FDH were much higher than in RTHβ and TSHoma. The FT3/FT4 values in RTHβ were significantly lower than in TSHoma. The degrees of SITSH in patients with truncations and frameshifts were more severe than those in patients with single amino acid deletions and single amino acid substitutions, and those in homozygous patients were more severe than those in heterozygous patients with cognate mutations. The FT3/FT4 ratios in RTHα were higher than 1.0.
Collapse
Affiliation(s)
- Tetsuya Tagami
- Department of Endocrinology and Metabolism, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan
- Clinical Research Institute for Endocrine and Metabolic Diseases, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan
| |
Collapse
|
8
|
Uncovering Evidence for Endocrine-Disrupting Chemicals That Elicit Differential Susceptibility through Gene-Environment Interactions. TOXICS 2021; 9:toxics9040077. [PMID: 33917455 PMCID: PMC8067468 DOI: 10.3390/toxics9040077] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 03/27/2021] [Accepted: 04/02/2021] [Indexed: 12/17/2022]
Abstract
Exposure to endocrine-disrupting chemicals (EDCs) is linked to myriad disorders, characterized by the disruption of the complex endocrine signaling pathways that govern development, physiology, and even behavior across the entire body. The mechanisms of endocrine disruption involve a complex system of pathways that communicate across the body to stimulate specific receptors that bind DNA and regulate the expression of a suite of genes. These mechanisms, including gene regulation, DNA binding, and protein binding, can be tied to differences in individual susceptibility across a genetically diverse population. In this review, we posit that EDCs causing such differential responses may be identified by looking for a signal of population variability after exposure. We begin by summarizing how the biology of EDCs has implications for genetically diverse populations. We then describe how gene-environment interactions (GxE) across the complex pathways of endocrine signaling could lead to differences in susceptibility. We survey examples in the literature of individual susceptibility differences to EDCs, pointing to a need for research in this area, especially regarding the exceedingly complex thyroid pathway. Following a discussion of experimental designs to better identify and study GxE across EDCs, we present a case study of a high-throughput screening signal of putative GxE within known endocrine disruptors. We conclude with a call for further, deeper analysis of the EDCs, particularly the thyroid disruptors, to identify if these chemicals participate in GxE leading to differences in susceptibility.
Collapse
|
9
|
Harris SE, De Blasio MJ, Zhao X, Ma M, Davies K, Wooding FBP, Hamilton RS, Blache D, Meredith D, Murray AJ, Fowden AL, Forhead AJ. Thyroid Deficiency Before Birth Alters the Adipose Transcriptome to Promote Overgrowth of White Adipose Tissue and Impair Thermogenic Capacity. Thyroid 2020; 30:794-805. [PMID: 32070265 PMCID: PMC7286741 DOI: 10.1089/thy.2019.0749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Background: Development of adipose tissue before birth is essential for energy storage and thermoregulation in the neonate and for cardiometabolic health in later life. Thyroid hormones are important regulators of growth and maturation in fetal tissues. Offspring hypothyroid in utero are poorly adapted to regulate body temperature at birth and are at risk of becoming obese and insulin resistant in childhood. The mechanisms by which thyroid hormones regulate the growth and development of adipose tissue in the fetus, however, are unclear. Methods: This study examined the structure, transcriptome, and protein expression of perirenal adipose tissue (PAT) in a fetal sheep model of thyroid hormone deficiency during late gestation. Proportions of unilocular (UL) (white) and multilocular (ML) (brown) adipocytes, and UL adipocyte size, were assessed by histological and stereological techniques. Changes to the adipose transcriptome were investigated by RNA sequencing and bioinformatic analysis, and proteins of interest were quantified by Western blotting. Results: Hypothyroidism in utero resulted in elevated plasma insulin and leptin concentrations and overgrowth of PAT in the fetus, specifically due to hyperplasia and hypertrophy of UL adipocytes with no change in ML adipocyte mass. RNA sequencing and genomic analyses showed that thyroid deficiency affected 34% of the genes identified in fetal adipose tissue. Enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) pathways were associated with adipogenic, metabolic, and thermoregulatory processes, insulin resistance, and a range of endocrine and adipocytokine signaling pathways. Adipose protein levels of signaling molecules, including phosphorylated S6-kinase (pS6K), glucose transporter isoform 4 (GLUT4), and peroxisome proliferator-activated receptor γ (PPARγ), were increased by fetal hypothyroidism. Fetal thyroid deficiency decreased uncoupling protein 1 (UCP1) protein and mRNA content, and UCP1 thermogenic capacity without any change in ML adipocyte mass. Conclusions: Growth and development of adipose tissue before birth is sensitive to thyroid hormone status in utero. Changes to the adipose transcriptome and phenotype observed in the hypothyroid fetus may have consequences for neonatal survival and the risk of obesity and metabolic dysfunction in later life.
Collapse
Affiliation(s)
- Shelley E Harris
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Miles J De Blasio
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Xiaohui Zhao
- Centre for Trophoblast Research, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Marcella Ma
- Genomics-Transcriptomics Core, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Katie Davies
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - FB Peter Wooding
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Russell S Hamilton
- Centre for Trophoblast Research, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Dominique Blache
- Genomics-Transcriptomics Core, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - David Meredith
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Abigail L Fowden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Alison J Forhead
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
- Corresponding author: Dr Alison J Forhead, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK; +44 1223 333853;
| |
Collapse
|
10
|
Goemann IM, Marczyk VR, Romitti M, Wajner SM, Maia AL. Current concepts and challenges to unravel the role of iodothyronine deiodinases in human neoplasias. Endocr Relat Cancer 2018; 25:R625-R645. [PMID: 30400023 DOI: 10.1530/erc-18-0097] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/10/2018] [Indexed: 12/20/2022]
Abstract
Thyroid hormones (THs) are essential for the regulation of several metabolic processes and the energy consumption of the organism. Their action is exerted primarily through interaction with nuclear receptors controlling the transcription of thyroid hormone-responsive genes. Proper regulation of TH levels in different tissues is extremely important for the equilibrium between normal cellular proliferation and differentiation. The iodothyronine deiodinases types 1, 2 and 3 are key enzymes that perform activation and inactivation of THs, thus controlling TH homeostasis in a cell-specific manner. As THs seem to exert their effects in all hallmarks of the neoplastic process, dysregulation of deiodinases in the tumoral context can be critical to the neoplastic development. Here, we aim at reviewing the deiodinases expression in different neoplasias and exploit the mechanisms by which they play an essential role in human carcinogenesis. TH modulation by deiodinases and other classical pathways may represent important targets with the potential to oppose the neoplastic process.
Collapse
Affiliation(s)
- Iuri Martin Goemann
- Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Vicente Rodrigues Marczyk
- Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Mirian Romitti
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, Brussels, Belgium
| | - Simone Magagnin Wajner
- Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Ana Luiza Maia
- Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| |
Collapse
|
11
|
Chen X, Zhou Y, Zhou M, Yin Q, Wang S. Diagnostic Values of Free Triiodothyronine and Free Thyroxine and the Ratio of Free Triiodothyronine to Free Thyroxine in Thyrotoxicosis. Int J Endocrinol 2018; 2018:4836736. [PMID: 29971103 PMCID: PMC6008621 DOI: 10.1155/2018/4836736] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 04/16/2018] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The results of previous studies on the usefulness of free triiodothyronine (FT3) to free thyroxine (FT4) are controversial. We investigated the usefulness of FT3, FT4, and FT3/FT4 ratio in differentiating Graves' disease (GD) from destructive thyroiditis. METHODS A total of 126 patients with untreated GD, 36 with painless thyroiditis, 18 with painful subacute thyroiditis, and 63 healthy controls, were recruited. The levels of FT3 and FT4 and the FT3/FT4 ratios for the different etiologies of thyrotoxicosis were evaluated separately by receiver operating characteristic (ROC) curve analysis. The expression levels of type 1 and type 2 deiodinase (DIO1 and DIO2) in thyroid tissues were also investigated. RESULTS The optimal cut-off values were 7.215 pmol/L for FT3, 21.71 pmol/L for FT4, and 0.4056 for the FT3/FT4 ratio. The specificity and positive predictive value of the FT3/FT4 ratio were highest for values > 0.4056. DIO1 mRNA expression was significantly higher in the thyroid tissue of patients with GD (P = 0.013). CONCLUSIONS We demonstrated that the FT3/FT4 ratio was useful in differentiating GD from destructive thyroiditis. In addition, a relatively high expression of type 1 deiodinase in the thyroid might be responsible for the high FT3/FT4 ratio in patients with GD.
Collapse
Affiliation(s)
- Xinxin Chen
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai 200025, China
| | - Yulin Zhou
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai 200025, China
| | - Mengxi Zhou
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai 200025, China
| | - Qinglei Yin
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai 200025, China
| | - Shu Wang
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai 200025, China
| |
Collapse
|
12
|
Mohácsik P, Erdélyi F, Baranyi M, Botz B, Szabó G, Tóth M, Haltrich I, Helyes Z, Sperlágh B, Tóth Z, Sinkó R, Lechan RM, Bianco AC, Fekete C, Gereben B. A Transgenic Mouse Model for Detection of Tissue-Specific Thyroid Hormone Action. Endocrinology 2018; 159:1159-1171. [PMID: 29253128 PMCID: PMC6283413 DOI: 10.1210/en.2017-00582] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 12/08/2017] [Indexed: 01/03/2023]
Abstract
Thyroid hormone (TH) is present in the systemic circulation and thus should affect all cells similarly in the body. However, tissues have a complex machinery that allows tissue-specific optimization of local TH action that calls for the assessment of TH action in a tissue-specific manner. Here, we report the creation of a TH action indicator (THAI) mouse model to study tissue-specific TH action. The model uses a firefly luciferase reporter readout in the context of an intact transcriptional apparatus and all elements of TH metabolism and transport and signaling. The THAI mouse allows the assessment of the changes of TH signaling in tissue samples or in live animals using bioluminescence, both in hypothyroidism and hyperthyroidism. Beyond pharmacologically manipulated TH levels, the THAI mouse is sufficiently sensitive to detect deiodinase-mediated changes of TH action in the interscapular brown adipose tissue (BAT) that preserves thermal homeostasis during cold stress. The model revealed that in contrast to the cold-induced changes of TH action in the BAT, the TH action in this tissue, at room temperature, is independent of noradrenergic signaling. Our data demonstrate that the THAI mouse can also be used to test TH receptor isoform-specific TH action. Thus, THAI mouse constitutes a unique model to study tissue-specific TH action within a physiological/pathophysiological context and test the performance of thyromimetics. In conclusion, THAI mouse provides an in vivo model to assess a high degree of tissue specificity of TH signaling, allowing alteration of tissue function in health and disease, independently of changes in circulating levels of TH.
Collapse
Affiliation(s)
- Petra Mohácsik
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
- János Szentágothai PhD School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Ferenc Erdélyi
- Medical Gene Technology Unit, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Mária Baranyi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Bálint Botz
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, Centre for Neuroscience, Pécs, Hungary
- Molecular Pharmacology Research Team, János Szentágothai Research Centre, Pécs, Hungary
| | - Gábor Szabó
- Medical Gene Technology Unit, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Mónika Tóth
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Irén Haltrich
- Second Department of Pediatrics, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Zsuzsanna Helyes
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, Centre for Neuroscience, Pécs, Hungary
- Molecular Pharmacology Research Team, János Szentágothai Research Centre, Pécs, Hungary
- Hungarian Academy of Sciences–University of Pécs, Hungarian Brain Research Program, Chronic Pain Research Group, University of Pécs Medical School, Pécs, Hungary
| | - Beáta Sperlágh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Zsuzsa Tóth
- Second Department of Pediatrics, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Richárd Sinkó
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
- János Szentágothai PhD School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Ronald M Lechan
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts
| | - Antonio C Bianco
- Division of Endocrinology and Metabolism, Rush University Medical Center, Chicago, Illinois
| | - Csaba Fekete
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts
- Correspondence: Csaba Fekete, MD, PhD, or Balázs Gereben, DVM, PhD, Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, 43 Szigony Street, Budapest, Hungary H-1083. E-mail: ; or
| | - Balázs Gereben
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| |
Collapse
|
13
|
Bice BD, Stephens MR, Georges SJ, Venancio AR, Bermant PC, Warncke AV, Affolter KE, Hidalgo JR, Angus-Hill ML. Environmental Enrichment Induces Pericyte and IgA-Dependent Wound Repair and Lifespan Extension in a Colon Tumor Model. Cell Rep 2018; 19:760-773. [PMID: 28445727 DOI: 10.1016/j.celrep.2017.04.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/06/2017] [Accepted: 04/01/2017] [Indexed: 02/08/2023] Open
Abstract
Environmental enrichment (EE) replicates mind-body therapy by providing complex housing to laboratory animals to improve their activity levels, behavior, and social interactions. Using a Tcf4Het/+ApcMin/+-mediated model of colon tumorigenesis, we found that EE vastly improved the survival of tumor-bearing animals, with differential effect on tumor load in male compared to female animals. Analysis of Tcf4Het/+ApcMin/+ males showed drastically reduced expression of circulating inflammatory cytokines and induced nuclear hormone receptor (NHR) signaling, both of which are common in the wound repair process. Interestingly, EE provoked tumor wound repair resolution through revascularization, plasma cell recruitment and IgA secretion, replacement of glandular tumor structures with pericytes in a process reminiscent of scarring, and normalization of microbiota. These EE-dependent changes likely underlie the profound improvement in survival of colon-tumor-bearing Tcf4Het/+ApcMin/+ males. Our studies highlight the exciting promise of EE in the design of future therapeutic strategies for colon cancer patients.
Collapse
Affiliation(s)
- Benjamin D Bice
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84132, USA
| | - Megan R Stephens
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84132, USA
| | - Stephanie J Georges
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84132, USA
| | - Ashlee R Venancio
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84132, USA
| | - Peter C Bermant
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84132, USA
| | - Annika V Warncke
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84132, USA
| | - Kajsa E Affolter
- Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Julio R Hidalgo
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84132, USA
| | - Melinda L Angus-Hill
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84132, USA.
| |
Collapse
|
14
|
van der Spek AH, Fliers E, Boelen A. The classic pathways of thyroid hormone metabolism. Mol Cell Endocrinol 2017; 458:29-38. [PMID: 28109953 DOI: 10.1016/j.mce.2017.01.025] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 12/21/2016] [Accepted: 01/17/2017] [Indexed: 12/15/2022]
Abstract
Thyroid hormones (TH) are crucial for growth and development and play an important role in energy homeostasis. Although serum TH levels are relatively constant in the physiological state, TH bioavailability at the tissue and cellular level is dependent on local TH metabolism. Circulating TH produced by the thyroid can be metabolized by a number of different pathways resulting in 1) activation of TH 2) deactivation of TH or 3) excretion of TH and subsequent metabolites. These pathways play an essential role in determining local TH levels and action. The major classical pathways of TH metabolism are deiodination, sulfation, glucuronidation, and ether-link cleavage. This review provides an overview of these pathways, their relative contributions to TH levels in the serum and in various organs and the changes in these pathways elicited by fasting and illness.
Collapse
Affiliation(s)
- Anne H van der Spek
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Anita Boelen
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
| |
Collapse
|
15
|
Senese R, Cioffi F, de Lange P, Leanza C, Iannucci LF, Silvestri E, Moreno M, Lombardi A, Goglia F, Lanni A. Both 3,5-Diiodo-L-Thyronine and 3,5,3'-Triiodo-L-Thyronine Prevent Short-term Hepatic Lipid Accumulation via Distinct Mechanisms in Rats Being Fed a High-Fat Diet. Front Physiol 2017; 8:706. [PMID: 28959215 PMCID: PMC5603695 DOI: 10.3389/fphys.2017.00706] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/31/2017] [Indexed: 12/14/2022] Open
Abstract
3,3′,5-triiodo-L-thyronine (T3) improves hepatic lipid accumulation by increasing lipid catabolism but it also increases lipogenesis, which at first glance appears contradictory. Recent studies have shown that 3,5-diiodothyronine (T2), a natural thyroid hormone derivative, also has the capacity to stimulate hepatic lipid catabolism, however, little is known about its possible effects on lipogenic gene expression. Because genes classically involved in hepatic lipogenesis such as SPOT14, acetyl-CoA-carboxylase (ACC), and fatty acid synthase (FAS) contain thyroid hormone response elements (TREs), we studied their transcriptional regulation, focusing on TRE-mediated effects of T3 compared to T2 in rats receiving high-fat diet (HFD) for 1 week. HFD rats showed a marked lipid accumulation in the liver, which was significantly reduced upon simultaneous administration of either T3 or T2 with the diet. When administered to HFD rats, T2, in contrast with T3, markedly downregulated the expression of the above-mentioned genes. T2 downregulated expression of the transcription factors carbohydrate-response element-binding protein (ChREBP) and sterol regulatory element binding protein-1c (SREBP-1c) involved in activation of transcription of these genes, which explains the suppressed expression of their target genes involved in lipogenesis. T3, however, did not repress expression of the TRE-containing ChREBP gene but repressed SREBP-1c expression. Despite suppression of SREBP-1c expression by T3 (which can be explained by the presence of nTRE in its promoter), the target genes were not suppressed, but normalized to HFD reference levels or even upregulated (ACC), partly due to the presence of TREs on the promoters of these genes and partly to the lack of suppression of ChREBP. Thus, T2 and T3 probably act by different molecular mechanisms to achieve inhibition of hepatic lipid accumulation.
Collapse
Affiliation(s)
- Rosalba Senese
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
| | - Federica Cioffi
- Dipartimento di Scienze e Tecnologie, Università degli Studi del SannioBenevento, Italy
| | - Pieter de Lange
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
| | - Cristina Leanza
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
| | - Liliana F Iannucci
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
| | - Elena Silvestri
- Dipartimento di Scienze e Tecnologie, Università degli Studi del SannioBenevento, Italy
| | - Maria Moreno
- Dipartimento di Scienze e Tecnologie, Università degli Studi del SannioBenevento, Italy
| | - Assunta Lombardi
- Dipartimento di Biologia, Università degli Studi di Napoli Federico IINaples, Italy
| | - Fernando Goglia
- Dipartimento di Scienze e Tecnologie, Università degli Studi del SannioBenevento, Italy
| | - Antonia Lanni
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, "Luigi Vanvitelli" CasertaCaserta, Italy
| |
Collapse
|
16
|
Regulation of type 1 iodothyronine deiodinase by LXRα. PLoS One 2017; 12:e0179213. [PMID: 28617824 PMCID: PMC5472309 DOI: 10.1371/journal.pone.0179213] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 05/25/2017] [Indexed: 11/24/2022] Open
Abstract
The iodothyronine deiodinases are selenoenzymes that regulate the activity of thyroid hormone via specific inner- or outer-ring deiodination. In humans, type 1 deiodinase (D1) is highly expressed in the liver, but the mechanism by which its gene expression is regulated remains to be elucidated. Liver X receptor α (LXRα), a transcription factor of the nuclear receptor superfamily, is highly expressed in the liver, where it functions as a sensor for excess intracellular oxysterols. LXRα interacts with other nuclear receptors on promoters of genes that contain a binding core sequence for nuclear receptors. In addition, it is reported that the promoter of the gene encoding human D1 (hDIO1) contains the core sequence for one of nuclear receptors, thyroid hormone receptor (TR). We investigated the involvement of LXRα in the regulation of hDIO1, in the liver. We performed hDIO1 promoter–reporter assays using a synthetic LXR agonist, T0901317, and compared promoter activity between a human liver carcinoma cell line, HepG2, and a clone of human embryonic kidney cells, TSA201. We defined the region between nucleotides −131 and −114, especially nucleotides −126 and −125, of the hDIO1 promoter as critical for basal and LXRα-mediated specific transcriptional activation in HepG2 cells. An increase in hDIO1 expression was observed in LXRα-stimulated cells, but absent in cycloheximide-treated cells, indicating that new protein synthesis is required for LXRα-mediated regulation of hDIO1. On the other hand, electrophoretic mobility shift assays revealed that LXRα and RXRα bound to the hDIO1 promoter. We also demonstrated that LXRα and TRβ compete with each other on this specific region of the promoter. In conclusion, our results indicated that LXRα plays a specific and important role in activation of TH by regulating D1, and that LXRα binds to and regulates the hDIO1 promoter, competing with TRβ on specific sequences within the promoter.
Collapse
|
17
|
The thyroid hormone nuclear receptors and the Wnt/β-catenin pathway: An intriguing liaison. Dev Biol 2017; 422:71-82. [DOI: 10.1016/j.ydbio.2017.01.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 12/26/2016] [Accepted: 01/04/2017] [Indexed: 12/11/2022]
|
18
|
Liu J, Hernandez-Ono A, Graham MJ, Galton VA, Ginsberg HN. Type 1 Deiodinase Regulates ApoA-I Gene Expression and ApoA-I Synthesis Independent of Thyroid Hormone Signaling. Arterioscler Thromb Vasc Biol 2016; 36:1356-66. [PMID: 27150392 DOI: 10.1161/atvbaha.116.307330] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/20/2016] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Plasma levels of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (ApoA-I) are reduced in individuals with defective insulin signaling. Initial studies using liver-specific insulin receptor (InsR) knockout mice identified reduced expression of type 1 deiodinase (Dio1) as a potentially novel link between defective hepatic insulin signaling and reduced expression of the ApoA-I gene. Our objective was to examine the regulation of ApoA-I expression by Dio1. APPROACH AND RESULTS Acute inactivation of InsR by adenoviral delivery of Cre recombinase to InsR floxed mice reduced HDL-C and expression of both ApoA-I and Dio1. Overexpression of Dio1 in InsR knockout mice restored HDL-C and ApoA-I levels and increased the expression of ApoA-I. Dio1 knockout mice had low expression of ApoA-I and reduced serum levels of HDL-C and ApoA-I. Treatment of C57BL/6J mice with antisense to Dio1 reduced ApoA-I mRNA, HDL-C, and serum ApoA-I. Hepatic 3,5,3'-triiodothyronine content was normal or elevated in InsR knockout mice or Dio1 knockout mice. Knockdown of either InsR or Dio1 by siRNA in HepG2 cells decreased the expression of ApoA-I and ApoA-I synthesis and secretion. siRNA knockdown of InsR or Dio1 decreased activity of a region of the ApoA-I promoter lacking thyroid hormone response elements (region B). Electrophoretic mobility shift assay demonstrated that reduced Dio1 expression decreased the binding of nuclear proteins to region B. CONCLUSIONS Reductions in Dio1 expression reduce the expression of ApoA-I in a 3,5,3'-triiodothyronine-/thyroid hormone response element-independent manner.
Collapse
Affiliation(s)
- Jing Liu
- From the Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY (J.L., A.H.-O., H.N.G.); Ionis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G.); and Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, NH (V.A.G.).
| | - Antonio Hernandez-Ono
- From the Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY (J.L., A.H.-O., H.N.G.); Ionis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G.); and Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, NH (V.A.G.)
| | - Mark J Graham
- From the Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY (J.L., A.H.-O., H.N.G.); Ionis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G.); and Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, NH (V.A.G.)
| | - Valerie Anne Galton
- From the Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY (J.L., A.H.-O., H.N.G.); Ionis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G.); and Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, NH (V.A.G.)
| | - Henry N Ginsberg
- From the Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY (J.L., A.H.-O., H.N.G.); Ionis Pharmaceuticals, Inc, Carlsbad, CA (M.J.G.); and Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, NH (V.A.G.).
| |
Collapse
|
19
|
Type 1 5′-deiodinase activity is inhibited by oxidative stress and restored by alpha-lipoic acid in HepG2 cells. Biochem Biophys Res Commun 2016; 472:496-501. [DOI: 10.1016/j.bbrc.2016.02.119] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 02/28/2016] [Indexed: 01/10/2023]
|
20
|
Fliers E, Bianco AC, Langouche L, Boelen A. Thyroid function in critically ill patients. Lancet Diabetes Endocrinol 2015; 3:816-25. [PMID: 26071885 PMCID: PMC4979220 DOI: 10.1016/s2213-8587(15)00225-9] [Citation(s) in RCA: 219] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 01/14/2015] [Accepted: 01/19/2015] [Indexed: 12/20/2022]
Abstract
Patients in the intensive care unit (ICU) typically present with decreased concentrations of plasma tri-iodothyronine, low thyroxine, and normal range or slightly decreased concentration of thyroid-stimulating hormone. This ensemble of changes is collectively known as non-thyroidal illness syndrome (NTIS). The extent of NTIS is associated with prognosis, but no proof exists for causality of this association. Initially, NTIS is a consequence of the acute phase response to systemic illness and macronutrient restriction, which might be beneficial. Pathogenesis of NTIS in long-term critical illness is more complex and includes suppression of hypothalamic thyrotropin-releasing hormone, accounting for persistently reduced secretion of thyroid-stimulating hormone despite low plasma thyroid hormone. In some cases distinguishing between NTIS and severe hypothyroidism, which is a rare primary cause for admission to the ICU, can be difficult. Infusion of hypothalamic-releasing factors can reactivate the thyroid axis in patients with NTIS, inducing an anabolic response. Whether this approach has a clinical benefit in terms of outcome is unknown. In this Series paper, we discuss diagnostic aspects, pathogenesis, and implications of NTIS as well as its distinction from severe, primary thyroid disorders in patients in the ICU.
Collapse
Affiliation(s)
- Eric Fliers
- Department of Endocrinology and Metabolism, Academic Medical Centre, University of Amsterdam, AZ, Amsterdam, Netherlands
| | - Antonio C Bianco
- Division of Endocrinology and Metabolism, Rush University Medical Center, Chicago, IL, USA
| | - Lies Langouche
- Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Anita Boelen
- Department of Endocrinology and Metabolism, Academic Medical Centre, University of Amsterdam, AZ, Amsterdam, Netherlands.
| |
Collapse
|
21
|
de Vries EM, Fliers E, Boelen A. The molecular basis of the non-thyroidal illness syndrome. J Endocrinol 2015; 225:R67-81. [PMID: 25972358 DOI: 10.1530/joe-15-0133] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/13/2015] [Indexed: 11/08/2022]
Abstract
The 'sick euthyroid syndrome' or 'non-thyroidal illness syndrome' (NTIS) occurs in a large proportion of hospitalized patients and comprises a variety of alterations in the hypothalamus-pituitary-thyroid (HPT) axis that are observed during illness. One of the hallmarks of NTIS is decreased thyroid hormone (TH) serum concentrations, often viewed as an adaptive mechanism to save energy. Downregulation of hypophysiotropic TRH neurons in the paraventricular nucleus of the hypothalamus and of TSH production in the pituitary gland points to disturbed negative feedback regulation during illness. In addition to these alterations in the central component of the HPT axis, changes in TH metabolism occur in a variety of TH target tissues during NTIS, dependent on the timing, nature and severity of the illness. Cytokines, released during illness, are known to affect a variety of genes involved in TH metabolism and are therefore considered a major determinant of NTIS. The availability of in vivo and in vitro models for NTIS has elucidated part of the mechanisms involved in the sometimes paradoxical changes in the HPT axis and TH responsive tissues. However, the pathogenesis of NTIS is still incompletely understood. This review focusses on the molecular mechanisms involved in the tissue changes in TH metabolism and discusses the gaps that still require further research.
Collapse
Affiliation(s)
- Emmely M de Vries
- Department of Endocrinology and Metabolism Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Anita Boelen
- Department of Endocrinology and Metabolism Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| |
Collapse
|
22
|
Srivastava J, Robertson CL, Gredler R, Siddiq A, Rajasekaran D, Akiel MA, Emdad L, Mas V, Mukhopadhyay ND, Fisher PB, Sarkar D. Astrocyte Elevated Gene-1 (AEG-1) Contributes to Non-thyroidal Illness Syndrome (NTIS) Associated with Hepatocellular Carcinoma (HCC). J Biol Chem 2015; 290:15549-15558. [PMID: 25944909 DOI: 10.1074/jbc.m115.649707] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Indexed: 12/11/2022] Open
Abstract
Non-thyroidal illness syndrome (NTIS), characterized by low serum 3,5,3'-triiodothyronine (T3) with normal l-thyroxine (T4) levels, is associated with malignancy. Decreased activity of type I 5'-deiodinase (DIO1), which converts T4 to T3, contributes to NTIS. T3 binds to thyroid hormone receptor, which heterodimerizes with retinoid X receptor (RXR) and regulates transcription of target genes, such as DIO1. NF-κB activation by inflammatory cytokines inhibits DIO1 expression. The oncogene astrocyte elevated gene-1 (AEG-1) inhibits RXR-dependent transcription and activates NF-κB. Here, we interrogated the role of AEG-1 in NTIS in the context of hepatocellular carcinoma (HCC). T3-mediated gene regulation was analyzed in human HCC cells, with overexpression or knockdown of AEG-1, and primary hepatocytes from AEG-1 transgenic (Alb/AEG-1) and AEG-1 knock-out (AEG-1KO) mice. Serum T3 and T4 levels were checked in Alb/AEG-1 mice and human HCC patients. AEG-1 and DIO1 levels in human HCC samples were analyzed by immunohistochemistry. AEG-1 inhibited T3-mediated gene regulation in human HCC cells and mouse hepatocytes. AEG-1 overexpression repressed and AEG-1 knockdown induced DIO1 expression. An inverse correlation was observed between AEG-1 and DIO1 levels in human HCC patients. Low T3 with normal T4 was observed in the sera of HCC patients and Alb/AEG-1 mice. Inhibition of co-activator recruitment to RXR and activation of NF-κB were identified to play a role in AEG-1-mediated down-regulation of DIO1. AEG-1 thus might play a role in NTIS associated with HCC and other cancers.
Collapse
Affiliation(s)
- Jyoti Srivastava
- Departments of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Chadia L Robertson
- Departments of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Rachel Gredler
- Departments of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Ayesha Siddiq
- Departments of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Devaraja Rajasekaran
- Departments of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Maaged A Akiel
- Departments of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Luni Emdad
- Departments of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Valeria Mas
- Department of Surgery, University of Virginia, Charlottesville, Virginia 22908-0625
| | | | - Paul B Fisher
- Departments of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298; Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298; VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Devanand Sarkar
- Departments of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298; Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298; VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, Virginia 23298.
| |
Collapse
|
23
|
Fliers E, Kalsbeek A, Boelen A. Beyond the fixed setpoint of the hypothalamus-pituitary-thyroid axis. Eur J Endocrinol 2014; 171:R197-208. [PMID: 25005935 DOI: 10.1530/eje-14-0285] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The hypothalamus-pituitary-thyroid (HPT) axis represents a classical example of an endocrine feedback loop. This review discusses dynamic changes in HPT axis setpoint regulation, identifying their molecular and cellular determinants, and speculates about their functional role. Hypothalamic thyrotropin-releasing hormone neurons were identified as key components of thyroid hormone (TH) setpoint regulation already in the 1980s, and this was followed by the demonstration of a pivotal role for the thyroid hormone receptor beta in negative feedback of TH on the hypothalamic and pituitary level. Gradually, the concept emerged of the HPT axis setpoint as a fixed entity, aiming at a particular TH serum concentration. However, TH serum concentrations appear to be variable and highly responsive to physiological and pathophysiological environmental factors, including the availability or absence of food, inflammation and clock time. During food deprivation and inflammation, TH serum concentrations decrease without a concomitant rise in serum TSH, reflecting a deviation from negative feedback regulation in the HPT axis. Surprisingly, TH action in peripheral organs in these conditions cannot be simply predicted by decreased serum TH concentrations. Instead, diverse environmental stimuli have differential effects on local TH metabolism, e.g. in liver and muscle, occurring quite independently from decreased TH serum concentrations. The net effect of these differential local changes is probably a major determinant of TH action at the tissue level. In sum, hypothalamic HPT axis setpoint regulation as well as TH metabolism at the peripheral organ level is flexible and dynamic, and may adapt the organism in an optimal way to a range of environmental challenges.
Collapse
Affiliation(s)
- Eric Fliers
- Department of Endocrinology and MetabolismAcademic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The NetherlandsHypothalamic Integration MechanismsNetherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and MetabolismAcademic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The NetherlandsHypothalamic Integration MechanismsNetherlands Institute for Neuroscience, Amsterdam, The Netherlands Department of Endocrinology and MetabolismAcademic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The NetherlandsHypothalamic Integration MechanismsNetherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Anita Boelen
- Department of Endocrinology and MetabolismAcademic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The NetherlandsHypothalamic Integration MechanismsNetherlands Institute for Neuroscience, Amsterdam, The Netherlands
| |
Collapse
|
24
|
Nagao H, Sasaki M, Imazu T, Takahashi K, Aoki H, Minato K. Effects of triiodothyronine on turnover rate and metabolizing enzymes for thyroxine in thyroidectomized rats. Life Sci 2014; 116:74-82. [DOI: 10.1016/j.lfs.2014.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 09/09/2014] [Accepted: 09/13/2014] [Indexed: 01/14/2023]
|
25
|
Howard MT, Carlson BA, Anderson CB, Hatfield DL. Translational redefinition of UGA codons is regulated by selenium availability. J Biol Chem 2013; 288:19401-13. [PMID: 23696641 DOI: 10.1074/jbc.m113.481051] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Incorporation of selenium into ~25 mammalian selenoproteins occurs by translational recoding whereby in-frame UGA codons are redefined to encode the selenium containing amino acid, selenocysteine (Sec). Here we applied ribosome profiling to examine the effect of dietary selenium levels on the translational mechanisms controlling selenoprotein synthesis in mouse liver. Dietary selenium levels were shown to control gene-specific selenoprotein expression primarily at the translation level by differential regulation of UGA redefinition and Sec incorporation efficiency, although effects on translation initiation and mRNA abundance were also observed. Direct evidence is presented that increasing dietary selenium causes a vast increase in ribosome density downstream of UGA-Sec codons for a subset of selenoprotein mRNAs and that the selenium-dependent effects on Sec incorporation efficiency are mediated in part by the degree of Sec-tRNA([Ser]Sec) Um34 methylation. Furthermore, we find evidence for translation in the 5'-UTRs for a subset of selenoproteins and for ribosome pausing near the UGA-Sec codon in those mRNAs encoding the selenoproteins most affected by selenium availability. These data illustrate how dietary levels of the trace element selenium can alter the readout of the genetic code to affect the expression of an entire class of proteins.
Collapse
Affiliation(s)
- Michael T Howard
- Department of Human Genetics, University of Utah, Salt Lake City, Utah 84112, USA.
| | | | | | | |
Collapse
|
26
|
Aguayo-Mazzucato C, Zavacki AM, Marinelarena A, Hollister-Lock J, El Khattabi I, Marsili A, Weir GC, Sharma A, Larsen PR, Bonner-Weir S. Thyroid hormone promotes postnatal rat pancreatic β-cell development and glucose-responsive insulin secretion through MAFA. Diabetes 2013; 62:1569-80. [PMID: 23305647 PMCID: PMC3636623 DOI: 10.2337/db12-0849] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Neonatal β cells do not secrete glucose-responsive insulin and are considered immature. We previously showed the transcription factor MAFA is key for the functional maturation of β cells, but the physiological regulators of this process are unknown. Here we show that postnatal rat β cells express thyroid hormone (TH) receptor isoforms and deiodinases in an age-dependent pattern as glucose responsiveness develops. In vivo neonatal triiodothyronine supplementation and TH inhibition, respectively, accelerated and delayed metabolic development. In vitro exposure of immature islets to triiodothyronine enhanced the expression of Mafa, the secretion of glucose-responsive insulin, and the proportion of responsive cells, all of which are effects that were abolished in the presence of dominant-negative Mafa. Using chromatin immunoprecipitation and electrophoretic mobility shift assay, we show that TH has a direct receptor-ligand interaction with the Mafa promoter and, using a luciferase reporter, that this interaction was functional. Thus, TH can be considered a physiological regulator of functional maturation of β cells via its induction of Mafa.
Collapse
Affiliation(s)
- Cristina Aguayo-Mazzucato
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Ann Marie Zavacki
- Thyroid Section, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Alejandra Marinelarena
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Jennifer Hollister-Lock
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Ilham El Khattabi
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Alessandro Marsili
- Thyroid Section, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Gordon C. Weir
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Arun Sharma
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - P. Reed Larsen
- Thyroid Section, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Susan Bonner-Weir
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
- Corresponding author: Susan Bonner-Weir,
| |
Collapse
|
27
|
Orozco A, Valverde-R C, Olvera A, García-G C. Iodothyronine deiodinases: a functional and evolutionary perspective. J Endocrinol 2012; 215:207-19. [PMID: 22872760 DOI: 10.1530/joe-12-0258] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
From an evolutionary perspective, deiodinases may be considered pivotal players in the emergence and functional diversification of both thyroidal systems (TS) and their iodinated messengers. To better understand the evolutionary pathway and the concomitant functional diversification of vertebrate deiodinases, in the present review we summarized the highlights of the available information regarding this ubiquitous enzymatic component that represents the final, common physiological link of TS. The information reviewed here suggests that deiodination of tyrosine metabolites is an ancient feature of all chordates studied to date and consequently, that it precedes the integration of the TS that characterize vertebrates. Phylogenetic analysis presented here points to D1 as the oldest vertebrate deiodinase and to D2 as the most recent deiodinase gene, a hypothesis that agrees with the notion that D2 is the most specialized and finely regulated member of the family and plays a key role in vertebrate neurogenesis. Thus, deiodinases seem to be major participants in the evolution and functional expansion of the complex regulatory network of TS found in vertebrates.
Collapse
Affiliation(s)
- Aurea Orozco
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Boulevard Juriquilla, Juriquilla, Querétaro, México.
| | | | | | | |
Collapse
|
28
|
Abstract
Iodothyronine deiodinases are important mediators of thyroid hormone (TH) action. They are present in tissues throughout the body where they catalyse 3,5,3'-triiodothyronine (T(3)) production and degradation via, respectively, outer and inner ring deiodination. Three different types of iodothyronine deiodinases (D1, D2 and D3) have been identified in vertebrates from fish to mammals. They share several common characteristics, including a selenocysteine residue in their catalytic centre, but show also some type-specific differences. These specific characteristics seem very well conserved for D2 and D3, while D1 shows more evolutionary diversity related to its Km, 6-n-propyl-2-thiouracil sensitivity and dependence on dithiothreitol as a cofactor in vitro. The three deiodinase types have an impact on systemic T(3) levels and they all contribute directly or indirectly to intracellular T(3) availability in different tissues. The relative contribution of each of them, however, varies amongst species, developmental stages and tissues. This is especially true for amphibians, where the impact of D1 may be minimal. D2 and D3 expression and activity respond to thyroid status in an opposite and conserved way, while the response of D1 is variable, especially in fish. Recently, a number of deiodinases have been cloned from lower chordates. Both urochordates and cephalochordates possess selenodeiodinases, although they cannot be classified in one of the three vertebrate types. In addition, the cephalochordate amphioxus also expresses a non-selenodeiodinase. Finally, deiodinase-like sequences have been identified in the genome of non-deuterostome organisms, suggesting that deiodination of externally derived THs may even be functionally relevant in a wide variety of invertebrates.
Collapse
Affiliation(s)
- Veerle M Darras
- Animal Physiology and Neurobiology Section, Department of Biology, Laboratory of Comparative Endocrinology, KU Leuven, Leuven, Belgium.
| | | |
Collapse
|
29
|
Kanamoto N, Tagami T, Ueda-Sakane Y, Sone M, Miura M, Yasoda A, Tamura N, Arai H, Nakao K. Forkhead box A1 (FOXA1) and A2 (FOXA2) oppositely regulate human type 1 iodothyronine deiodinase gene in liver. Endocrinology 2012; 153:492-500. [PMID: 22067325 DOI: 10.1210/en.2011-1310] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Type 1 iodothyronine deiodinase (D1), a selenoenzyme that catalyzes the bioactivation of thyroid hormone, is expressed mainly in the liver. Its expression and activity are modulated by several factors, but the precise mechanism of its transcriptional regulation remains unclear. In the present study, we have analyzed the promoter of human D1 gene (hDIO1) to identify factors that prevalently increase D1 activity in the human liver. Deletion and mutation analyses demonstrated that a forkhead box (FOX)A binding site and an E-box site within the region between nucleotides -187 and -132 are important for hDIO1 promoter activity in the liver. EMSA demonstrated that FOXA1 and FOXA2 specifically bind to the FOXA binding site and that upstream stimulatory factor (USF) specifically binds to the E-box element. Overexpression of FOXA2 decreased hDIO1 promoter activity, and short interfering RNA-mediated knockdown of FOXA2 increased the expression of hDIO1 mRNA. In contrast, overexpression of USF1/2 increased hDIO1 promoter activity. Short interfering RNA-mediated knockdown of FOXA1 decreased the expression of hDIO1 mRNA, but knockdown of both FOXA1 and FOXA2 restored it. The response of the hDIO1 promoter to USF was greatly attenuated in the absence of FOXA1. Taken together, these results indicate that a balance of FOXA1 and FOXA2 expression modulates hDIO1 expression in the liver.
Collapse
Affiliation(s)
- Naotetsu Kanamoto
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Casula S, Bianco AC. Thyroid hormone deiodinases and cancer. Front Endocrinol (Lausanne) 2012; 3:74. [PMID: 22675319 PMCID: PMC3365412 DOI: 10.3389/fendo.2012.00074] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 05/15/2012] [Indexed: 12/24/2022] Open
Abstract
Deiodinases constitute a group of thioredoxin fold-containing selenoenzymes that play an important function in thyroid hormone homeostasis and control of thyroid hormone action. There are three known deiodinases: D1 and D2 activate the pro-hormone thyroxine (T4) to T3, the most active form of thyroid hormone, while D3 inactivates thyroid hormone and terminates T3 action. A number of studies indicate that deiodinase expression is altered in several types of cancers, suggesting that (i) they may represent a useful cancer marker and/or (ii) could play a role in modulating cell proliferation - in different settings thyroid hormone modulates cell proliferation. For example, although D2 is minimally expressed in human and rodent skeletal muscle, its expression level in rhabdomyosarcoma (RMS)-13 cells is threefold to fourfold higher. In basal cell carcinoma (BCC) cells, sonic hedgehog (Shh)-induced cell proliferation is accompanied by induction of D3 and inactivation of D2. Interestingly a fivefold reduction in the growth of BCC in nude mice was observed if D3 expression was knocked down. A decrease in D1 activity has been described in renal clear cell carcinoma, primary liver cancer, lung cancer, and some pituitary tumors, while in breast cancer cells and tissue there is an increase in D1 activity. Furthermore D1 mRNA and activity were found to be decreased in papillary thyroid cancer while D1 and D2 activities were significantly higher in follicular thyroid cancer tissue, in follicular adenoma, and in anaplastic thyroid cancer. It is conceivable that understanding how deiodinase dysregulation in tumor cells affect thyroid hormone signaling and possibly interfere with tumor progression could lead to new antineoplastic approaches.
Collapse
Affiliation(s)
- Sabina Casula
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of MedicineMiami, FL, USA
| | - Antonio C. Bianco
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of MedicineMiami, FL, USA
- *Correspondence: Antonio C. Bianco, University of Miami Miller School of Medicine, Batchelor Research Building, 1400 N.W. 10th Avenue, Suite 601, Miami, FL 33136, USA. e-mail:
| |
Collapse
|
31
|
Boelen A, Kwakkel J, Fliers E. Beyond low plasma T3: local thyroid hormone metabolism during inflammation and infection. Endocr Rev 2011; 32:670-93. [PMID: 21791567 DOI: 10.1210/er.2011-0007] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Decreased serum thyroid hormone concentrations in severely ill patients were first reported in the 1970s, but the functional meaning of the observed changes in thyroid hormone levels, together known as nonthyroidal illness syndrome (NTIS), remains enigmatic. Although the common view was that NTIS results in overall down-regulation of metabolism in order to save energy, recent work has shown a more complex picture. NTIS comprises marked variation in transcriptional and translational activity of genes involved in thyroid hormone metabolism, ranging from inhibition to activation, dependent on the organ or tissue studied. Illness-induced changes in each of these organs appear to be very different during acute or chronic inflammation, adding an additional level of complexity. Organ- and timing-specific changes in the activity of thyroid hormone deiodinating enzymes (deiodinase types 1, 2, and 3) highlight deiodinases as proactive players in the response to illness, whereas the granulocyte is a novel and potentially important cell type involved in NTIS during bacterial infection. Although acute NTIS can be seen as an adaptive response to support the immune response, NTIS may turn disadvantageous when critical illness enters a chronic phase necessitating prolonged life support. For instance, changes in thyroid hormone metabolism in muscle during critical illness may be relevant for the pathogenesis of myopathy associated with prolonged ventilator dependence. This review focuses on NTIS as a timing-related and organ-specific response to illness, occurring independently from the decrease in serum thyroid hormone levels and potentially relevant for disease progression.
Collapse
Affiliation(s)
- Anita Boelen
- Department of Endocrinology and Metabolism, F5-165, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands.
| | | | | |
Collapse
|
32
|
Abstract
Thyroid hormones (TH) regulate key cellular processes, including proliferation, differentiation, and apoptosis in virtually all human cells. Disturbances in TH pathway and the resulting deregulation of these processes have been linked with neoplasia. The concentrations of TH in peripheral tissues are regulated via the activity of iodothyronine deiodinases. There are 3 types of these enzymes: type 1 and type 2 deiodinases are involved in TH activation while type 3 deiodinase inactivates TH. Expression and activity of iodothyronine deiodinases are disturbed in different types of neoplasia. According to the limited number of studies in cancer cell lines and mouse models changes in intratumoral and extratumoral T3 concentrations may influence proliferation rate and metastatic progression. Recent findings showing that increased expression of type 3 deiodinases may lead to enhanced tumoral proliferation support the idea that deiodinating enzymes have the potential to influence cancer progression. This review summarizes the observations of impaired expression and activity in different cancer types, published to date, and the mechanisms behind these alterations, including impaired regulation via TH receptors, transforming growth factor-β, and Sonic-hedgehog pathway. Possible roles of deiodinases as cancer markers and potential modulators of tumor progression are also discussed.
Collapse
Affiliation(s)
- A Piekiełko-Witkowska
- Department of Biochemistry and Molecular Biology, The Medical Centre of Postgraduate Education, Warsaw, Poland.
| | | |
Collapse
|
33
|
Belakavadi M, Dell J, Grover GJ, Fondell JD. Thyroid hormone suppression of β-amyloid precursor protein gene expression in the brain involves multiple epigenetic regulatory events. Mol Cell Endocrinol 2011; 339:72-80. [PMID: 21458529 DOI: 10.1016/j.mce.2011.03.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 03/15/2011] [Accepted: 03/24/2011] [Indexed: 12/14/2022]
Abstract
Thyroid hormone (T3) suppresses cerebral gene expression of the β-amyloid precursor protein (APP), an integral membrane protein that plays a key role in the onset and progression of Alzheimer's disease. However, the mechanisms by which T3 signaling pathways inhibit APP gene transcription in the brain remain unclear. By carrying out chromatin immunoprecipitation with neuroblastoma cells and primary rat brain tissue, we show for the first time that thyroid hormone receptors (TRs) directly bind at the APP gene in vivo at a promoter region containing a negative T3-response element. We further show that T3 treatment decreases both histone H3 acetylation and histone H3 lysine 4 methylation at the APP promoter and that chemical inhibitors of histone deacetylases and histone lysine demethylase abrogate T3-dependent APP silencing. Our findings thus suggest that TRs actively facilitate T3-dependent silencing of APP gene expression via the recruitment of distinct histone modifying enzymes associated with transcriptional repression.
Collapse
Affiliation(s)
- Madesh Belakavadi
- Department of Physiology and Biophysics, Robert Wood Johnson Medical School, UMDNJ, Piscataway, NJ 08854, USA
| | | | | | | |
Collapse
|
34
|
Ito M, Toyoda N, Nomura E, Takamura Y, Amino N, Iwasaka T, Takamatsu J, Miyauchi A, Nishikawa M. Type 1 and type 2 iodothyronine deiodinases in the thyroid gland of patients with 3,5,3'-triiodothyronine-predominant Graves' disease. Eur J Endocrinol 2011; 164:95-100. [PMID: 20937676 DOI: 10.1530/eje-10-0736] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE 3,5,3'-triiodothyronine-predominant Graves' disease (T(3)-P-GD) is characterized by a persistently high serum T(3) level and normal or even lower serum thyroxine (T(4)) level during antithyroid drug therapy. The source of this high serum T(3) level has not been clarified. Our objective was to evaluate the contribution of type 1 and type 2 iodothyronine deiodinase (D1 (or DIO1) and D2 (or DIO2) respectively) in the thyroid gland to the high serum T(3) level in T(3)-P-GD. METHODS We measured the activity and mRNA level of both D1 and D2 in the thyroid tissues of patients with T(3)-P-GD (n=13) and common-type GD (CT-GD) (n=18) who had been treated with methimazole up until thyroidectomy. RESULTS Thyroidal D1 activity in patients with T(3)-P-GD (492.7±201.3 pmol/mg prot per h) was significantly higher (P<0.05) than that in patients with CT-GD (320.7±151.9 pmol/mg prot per h). On the other hand, thyroidal D2 activity in patients with T(3)-P-GD (823.9±596.4 fmol/mg prot per h) was markedly higher (P<0.005) than that in patients with CT-GD (194.8±131.6 fmol/mg prot per h). There was a significant correlation between the thyroidal D1 activity in patients with T(3)-P-GD and CT-GD and the serum FT(3)-to-FT(4) ratio (r=0.370, P<0.05). Moreover, there was a strong correlation between the thyroidal D2 activity in those patients and the serum FT(3)-to-FT(4) ratio (r=0.676, P<0.001). CONCLUSIONS Our results suggest that the increment of thyroidal deiodinase activity, namely D1 and especially D2 activities, may be responsible for the higher serum FT(3)-to-FT(4) ratio in T(3)-P-GD.
Collapse
|
35
|
Untranslated regions of thyroid hormone receptor beta 1 mRNA are impaired in human clear cell renal cell carcinoma. Biochim Biophys Acta Mol Basis Dis 2010; 1802:995-1005. [PMID: 20691260 DOI: 10.1016/j.bbadis.2010.07.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 07/26/2010] [Accepted: 07/29/2010] [Indexed: 12/12/2022]
Abstract
Thyroid hormone receptor β1 (TRβ1) is a hormone-dependent transcription factor activated by 3,5,3'-l-triiodothyronine (T3). TRβ1 functions as a tumor suppressor and disturbances of the THRB gene are frequent findings in cancer. Translational control mediated by untranslated regions (UTRs) regulates cell proliferation, metabolism and responses to cellular stress, processes that are involved in carcinogenesis. We hypothesized that reduced TRβ1 expression in clear cell renal cell cancer (ccRCC) results from regulatory effects of TRβ1 5' and 3'UTRs on protein translation. We determined TRβ1 expression and alternative splicing of TRβ1 5' and 3'UTRs in ccRCC and control tissue together with expression of the type 1 deiodinase enzyme (coded by DIO1, a TRβ1 target gene). Tissue concentrations of T3 (which are generated in part by D1) and expression of miRNA-204 (an mRNA inhibitor for which a putative interaction site was identified in the TRβ1 3'UTR) were also determined. TRβ1 mRNA and protein levels were reduced by 70% and 91% in ccRCC and accompanied by absent D1 protein, a 58% reduction in tissue T3 concentration and 2-fold increase in miRNA-204. Structural analysis of TRβ1 UTR variants indicated that reduced TRβ1 expression may be maintained in ccRCC by posttranscriptional mechanisms involving 5'UTRs and miRNA-204. The tumor suppressor activity of TRβ1 indicates that reduced TRβ1 expression and tissue hypothyroidism in ccRCC tumors is likely to be involved in the process of carcinogenesis or in maintaining a proliferative advantage to malignant cells.
Collapse
|
36
|
Cyclin-dependent kinase 8 positively cooperates with Mediator to promote thyroid hormone receptor-dependent transcriptional activation. Mol Cell Biol 2010; 30:2437-48. [PMID: 20231357 DOI: 10.1128/mcb.01541-09] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mediator is a multisubunit assemblage of proteins originally identified in humans as a coactivator bound to thyroid hormone receptors (TRs) and essential for thyroid hormone (T3)-dependent transcription. Cyclin-dependent kinase 8 (CDK8), cyclin C, MED12, and MED13 form a variably associated Mediator subcomplex (termed the CDK8 module) whose functional role in TR-dependent transcription remains unclear. Using in vitro and cellular approaches, we show here that Mediator complexes containing the CDK8 module are specifically recruited into preinitiation complexes at the TR target gene type I deiodinase (DioI) together with RNA polymerase II (Pol II) in a TR- and T3-dependent manner. We found that CDK8 is essential for robust T3-dependent Dio1 transcription and that CDK8 knockdown via RNA interference decreased Pol II occupancy, and also the recruitment of the Pol II kinase CDK9, at the DioI promoter. Chromatin immunoprecipitation revealed CDK8 occupancy at the DioI promoter concurrent with active transcription, thus suggesting CDK8 involvement in transcriptional reinitiation. Mutagenesis assays showed that CDK8 kinase activity is necessary for full T3-dependent DioI activation, whereas in vitro kinase studies indicated that CDK8 may contribute to Pol II phosphorylation. Collectively, our data suggest CDK8 plays an important coactivator role in TR-dependent transcription by promoting Pol II recruitment and activation at TR target gene promoters.
Collapse
|
37
|
Campinho MA, Galay-Burgos M, Sweeney GE, Power DM. Coordination of deiodinase and thyroid hormone receptor expression during the larval to juvenile transition in sea bream (Sparus aurata, Linnaeus). Gen Comp Endocrinol 2010; 165:181-94. [PMID: 19549532 DOI: 10.1016/j.ygcen.2009.06.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 06/16/2009] [Accepted: 06/18/2009] [Indexed: 11/13/2022]
Abstract
To test the hypothesis that THs play an important role in the larval to juvenile transition in the marine teleost model, sea bream (Sparus auratus), key elements of the thyroid axis were analysed during development. Specific RT-PCR and Taqman quantitative RT-PCR were established and used to measure sea bream iodothyronine deiodinases and thyroid hormone receptor (TR) genes, respectively. Expression of deiodinases genes (D1 and D2) which encode enzymes producing T3, TRs and T4 levels start to increase at 20-30 days post-hatch (dph; beginning of metamorphosis), peak at about 45 dph (climax) and decline to early larval levels after 90-100 dph (end of metamorphosis) when fish are fully formed juveniles. The profile of these different TH elements during sea bream development is strikingly similar to that observed during the TH driven metamorphosis of flatfish and suggests that THs play an analogous role in the larval to juvenile transition in this species and probably also in other pelagic teleosts. However, the effect of T3 treatment on deiodinases and TR transcript abundance in sea bream is not as clear cut as in larval flatfish and tadpoles indicating divergence in the responsiveness of TH axis elements and highlighting the need for further studies of this axis during development of fish.
Collapse
Affiliation(s)
- Marco António Campinho
- Comparative Molecular Endocrinology Group, Marine Science Centre (CCMAR), Universidade do Algarve, 8005-139 Faro, Portugal
| | | | | | | |
Collapse
|
38
|
Stoytcheva ZR, Berry MJ. Transcriptional regulation of mammalian selenoprotein expression. Biochim Biophys Acta Gen Subj 2009; 1790:1429-40. [PMID: 19465084 DOI: 10.1016/j.bbagen.2009.05.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 05/05/2009] [Accepted: 05/18/2009] [Indexed: 01/23/2023]
Abstract
BACKGROUND Selenoproteins contain the twenty-first amino acid, selenocysteine, and are involved in cellular defenses against oxidative damage, important metabolic and developmental pathways, and responses to environmental challenges. Elucidating the mechanisms regulating selenoprotein expression at the transcriptional level is a key to understanding how these mechanisms are called into play to respond to the changing environment. METHODS This review summarizes published studies on transcriptional regulation of selenoprotein genes, focused primarily on genes whose encoded protein functions are at least partially understood. This is followed by in silico analysis of predicted regulatory elements in selenoprotein genes, including those in the aforementioned category as well as the genes whose functions are not known. RESULTS Our findings reveal regulatory pathways common to many selenoprotein genes, including several involved in stress-responses. In addition, tissue-specific regulatory factors are implicated in regulating many selenoprotein genes. CONCLUSIONS These studies provide new insights into how selenoprotein genes respond to environmental and other challenges, and the roles these proteins play in allowing cells to adapt to these changes. GENERAL SIGNIFICANCE Elucidating the regulatory mechanisms affecting selenoprotein expression is essential for understanding their roles in human diseases, and for developing diagnostic and potential therapeutic approaches to address dysregulation of members of this gene family.
Collapse
Affiliation(s)
- Zoia R Stoytcheva
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Suite 222, Honolulu, HI 96813, USA
| | | |
Collapse
|
39
|
Capuco AV, Connor EE, Wood DL. Regulation of mammary gland sensitivity to thyroid hormones during the transition from pregnancy to lactation. Exp Biol Med (Maywood) 2008; 233:1309-14. [PMID: 18641053 DOI: 10.3181/0803-rm-85] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Thyroid hormones are galactopoietic and help to establish the mammary gland's metabolic priority during lactation. Expression patterns for genes that can alter tissue sensitivity to thyroid hormones and thyroid hormone activity were evaluated in the mammary gland and liver of cows at 53, 35, 20, and 7 days before expected parturition, and 14 and 90 days into the subsequent lactation. Transcript abundance for the three isoforms of iodothyronine deiodinase, type I (DIO1), type II (DIO2) and type III (DIO3), thyroid hormone receptors alpha1 (TRalpha1), alpha2 (TRalpha2) and beta1 (TRbeta1), and retinoic acid receptors alpha (RXRalpha) and gamma (RXRgamma), which act as coregulators of thyroid hormone receptor action, were evaluated by quantitative RT-PCR. The DIO3 is a 5-deiodinase that produces inactive iodothyronine metabolites, whereas DIO1 and DIO2 generate the active thyroid hormone, triiodothyronine, from the relatively inactive precursor, thyroxine. Low copy numbers of DIO3 transcripts were present in mammary gland and liver. DIO2 was the predominant isoform expressed in mammary gland and DIO1 was the predominant isoform expressed in liver. Quantity of DIO1 mRNA in liver tissues did not differ with physiological state, but tended to be lowest during lactation. Quantity of DIO2 mRNA in mammary gland increased during lactation (P < 0.05), with copy numbers at 90 days of lactation 6-fold greater than at 35 and 20 days prepartum. When ratios of DIO2/DIO3 mRNA were evaluated, the increase was more pronounced (>100-fold). Quantity of TRbeta1 mRNA in mammary gland increased with onset of lactation, whereas TRalpha1 and TRalpha2 transcripts did not vary with physiological state. Conversely, quantity of RXRalpha mRNA decreased during late gestation to low levels during early lactation. Data suggest that increased expression of mammary TRbeta1 and DIO2, and decreased RXRalpha, provide a mechanism to increase thyroid hormone activity within the mammary gland during lactation.
Collapse
Affiliation(s)
- A V Capuco
- Bovine Functional Genomics Laboratory, USDA-ARS, Powder-Mill Road, BARC-East, Beltsville, MD 20705, USA.
| | | | | |
Collapse
|
40
|
Hepatocyte nuclear factor 4alpha contributes to thyroid hormone homeostasis by cooperatively regulating the type 1 iodothyronine deiodinase gene with GATA4 and Kruppel-like transcription factor 9. Mol Cell Biol 2008; 28:3917-31. [PMID: 18426912 DOI: 10.1128/mcb.02154-07] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Type 1 iodothyronine deiodinase (Dio1), a selenoenzyme catalyzing the bioactivation of thyroid hormone, is highly expressed in the liver. Dio1 mRNA and enzyme activity levels are markedly reduced in the livers of hepatocyte nuclear factor 4alpha (HNF4alpha)-null mice, thus accounting for its liver-specific expression. Consistent with this deficiency, serum T4 and rT3 concentrations are elevated in these mice compared with those in HNF4alpha-floxed control littermates; however, serum T3 levels are unchanged. Promoter analysis of the mouse Dio1 gene demonstrated that HNF4alpha plays a key role in the transactivation of the mouse Dio1 gene. Deletion and substitution mutation analyses demonstrated that a proximal HNF4alpha site (direct repeat 1 [TGGACAAAGGTGC]; HNF4alpha-RE) is crucial for transactivation of the mouse Dio1 gene by HNF4alpha. Mouse Dio1 is also stimulated by thyroid hormone signaling, but a direct role for thyroid hormone receptor action has not been reported. We also showed that thyroid hormone-inducible Krüppel-like factor 9 (KLF9) stimulates the mouse Dio1 promoter very efficiently through two CACCC sequences that are located on either side of HNF4alpha-RE. Furthermore, KLF9 functions together with HNF4alpha and GATA4 to synergistically activate the mouse Dio1 promoter, suggesting that Dio1 is regulated by thyroid hormone in the mouse through an indirect mechanism requiring prior KLF9 induction. In addition, we showed that physical interactions between the C-terminal zinc finger domain (Cf) of GATA4 and activation function 2 of HNF4alpha and between the basic domain adjacent to Cf of GATA4 and a C-terminal domain of KLF9 are both required for this synergistic response. Taken together, these results suggest that HNF4alpha regulates thyroid hormone homeostasis through transcriptional regulation of the mouse Dio1 gene with GATA4 and KLF9.
Collapse
|
41
|
Sagar GDV, Gereben B, Callebaut I, Mornon JP, Zeöld A, Curcio-Morelli C, Harney JW, Luongo C, Mulcahey MA, Larsen PR, Huang SA, Bianco AC. The thyroid hormone-inactivating deiodinase functions as a homodimer. Mol Endocrinol 2008; 22:1382-93. [PMID: 18356288 DOI: 10.1210/me.2007-0490] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The type 3 deiodinase (D3) inactivates thyroid hormone action by catalyzing tissue-specific inner ring deiodination, predominantly during embryonic development. D3 has gained much attention as a player in the euthyroid sick syndrome, given its robust reactivation during injury and/or illness. Whereas much of the structure biology of the deiodinases is derived from studies with D2, a dimeric endoplasmic reticulum obligatory activating deiodinase, little is known about the holostructure of the plasma membrane resident D3, the deiodinase capable of thyroid hormone inactivation. Here we used fluorescence resonance energy transfer in live cells to demonstrate that D3 exists as homodimer. While D3 homodimerized in its native state, minor heterodimerization was also observed between D3:D1 and D3:D2 in intact cells, the significance of which remains elusive. Incubation with 0.5-1.2 m urea resulted in loss of D3 homodimerization as assessed by bioluminescence resonance energy transfer and a proportional loss of enzyme activity, to a maximum of approximately 50%. Protein modeling using a D2-based scaffold identified potential dimerization surfaces in the transmembrane and globular domains. Truncation of the transmembrane domain (DeltaD3) abrogated dimerization and deiodinase activity except when coexpressed with full-length catalytically inactive deiodinase, thus assembled as DeltaD3:D3 dimer; thus the D3 globular domain also exhibits dimerization surfaces. In conclusion, the inactivating deiodinase D3 exists as homo- or heterodimer in living intact cells, a feature that is critical for their catalytic activities.
Collapse
Affiliation(s)
- G D Vivek Sagar
- Brigham and Women's Hospital, Harvard Medical School , Boston, Massachusetts 02115, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Schmutzler C, Gotthardt I, Hofmann PJ, Radovic B, Kovacs G, Stemmler L, Nobis I, Bacinski A, Mentrup B, Ambrugger P, Grüters A, Malendowicz LK, Christoffel J, Jarry H, Seidlovà-Wuttke D, Wuttke W, Köhrle J. Endocrine disruptors and the thyroid gland--a combined in vitro and in vivo analysis of potential new biomarkers. ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115 Suppl 1:77-83. [PMID: 18174954 PMCID: PMC2174406 DOI: 10.1289/ehp.9369] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 10/23/2006] [Indexed: 05/17/2023]
Abstract
BACKGROUND There is growing evidence that, in addition to the reproductive system, the hypothalamic-pituitary-thyroid axis is a target of endocrine-disrupting compounds (EDCs). However, this is not reflected adequately in current screening and assessment procedures for endocrine activity that to date determine only general parameters of thyroid function. OBJECTIVE AND METHODS We used several in vitro and ex vivo assays in an attempt to identify suitable biomarkers for antithyroid action testing a selected panel of putative EDCs. RESULTS In vitro we detected stimulation or inhibition of iodide uptake into FRTL-5 rat thyroid cells, inhibition of thyroid hormone binding to transthyretin, agonistic or antagonistic effects in a thyroid hormone receptor-dependent reporter assay, and inhibition of thyroid peroxidase using a novel assay system based on human recombinant thyroperoxidase that might be suitable for routine screening for potential EDCs. In rats, chronic application of several EDCs led to changes in thyroid morphology, alterations of thyrotropin and thyroid hormone serum levels as well as alterations in peripheral thyroid hormone-regulated end points such as malic enzyme and type I 5'-deiodinase activity. CONCLUSIONS As the effects of EDCs do not reflect classic mechanisms of hormone-dependent regulation and feedback, we believe multitarget and multimodal actions of EDCs affect the hypothalamic-pituitary-thyroid axis. These complex effects require a diverse approach for screening, evaluation, and risk assessment of potential antithyroid compounds. This approach involves novel in vitro or cell-based screening assays in order to assess thyroid hormone synthesis, transport, metabolism, and action as well as in vivo assays to measure thyroid hormone-regulated tissue-specific and developmental end points in animals.
Collapse
Affiliation(s)
- Cornelia Schmutzler
- Institut für Experimentelle Endokrinologie, Charité - Universitätsmedizin Berlin, Berlin, Germany.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Papp LV, Lu J, Holmgren A, Khanna KK. From selenium to selenoproteins: synthesis, identity, and their role in human health. Antioxid Redox Signal 2007; 9:775-806. [PMID: 17508906 DOI: 10.1089/ars.2007.1528] [Citation(s) in RCA: 856] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The requirement of the trace element selenium for life and its beneficial role in human health has been known for several decades. This is attributed to low molecular weight selenium compounds, as well as to its presence within at least 25 proteins, named selenoproteins, in the form of the amino acid selenocysteine (Sec). Incorporation of Sec into selenoproteins employs a unique mechanism that involves decoding of the UGA codon. This process requires multiple features such as the selenocysteine insertion sequence (SECIS) element and several protein factors including a specific elongation factor EFSec and the SECIS binding protein 2, SBP2. The function of most selenoproteins is currently unknown; however, thioredoxin reductases (TrxR), glutathione peroxidases (GPx) and thyroid hormone deiodinases (DIO) are well characterised selenoproteins involved in redox regulation of intracellular signalling, redox homeostasis and thyroid hormone metabolism. Recent evidence points to a role for selenium compounds as well as selenoproteins in the prevention of some forms of cancer. A number of clinical trials are either underway or being planned to examine the effects of selenium on cancer incidence. In this review we describe some of the recent progress in our understanding of the mechanism of selenoprotein synthesis, the role of selenoproteins in human health and disease and the therapeutic potential of some of these proteins.
Collapse
Affiliation(s)
- Laura Vanda Papp
- Queensland Institute of Medical Research, Cancer and Cell Biology Division, Herston, QLD, Australia
| | | | | | | |
Collapse
|
44
|
Sagar GDV, Gereben B, Callebaut I, Mornon JP, Zeöld A, da Silva WS, Luongo C, Dentice M, Tente SM, Freitas BCG, Harney JW, Zavacki AM, Bianco AC. Ubiquitination-induced conformational change within the deiodinase dimer is a switch regulating enzyme activity. Mol Cell Biol 2007; 27:4774-83. [PMID: 17452445 PMCID: PMC1951476 DOI: 10.1128/mcb.00283-07] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ubiquitination is a critical posttranslational regulator of protein stability and/or subcellular localization. Here we show that ubiquitination can also regulate proteins by transiently inactivating enzymatic function through conformational change in a dimeric enzyme, which can be reversed upon deubiquitination. Our model system is the thyroid hormone-activating type 2 deiodinase (D2), an endoplasmic reticulum-resident type 1 integral membrane enzyme. D2 exists as a homodimer maintained by interacting surfaces at its transmembrane and globular cytosolic domains. The D2 dimer associates with the Hedgehog-inducible ubiquitin ligase WSB-1, the ubiquitin conjugase UBC-7, and VDU-1, a D2-specific deubiquitinase. Upon binding of T4, its natural substrate, D2 is ubiquitinated, which inactivates the enzyme by interfering with D2's globular interacting surfaces that are critical for dimerization and catalytic activity. This state of transient inactivity and change in dimer conformation persists until deubiquitination. The continuous association of D2 with this regulatory protein complex supports rapid cycles of deiodination, conjugation to ubiquitin, and enzyme reactivation by deubiquitination, allowing tight control of thyroid hormone action.
Collapse
Affiliation(s)
- G D Vivek Sagar
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
|
46
|
Forhead AJ, Curtis K, Kaptein E, Visser TJ, Fowden AL. Developmental control of iodothyronine deiodinases by cortisol in the ovine fetus and placenta near term. Endocrinology 2006; 147:5988-94. [PMID: 16959839 DOI: 10.1210/en.2006-0712] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Preterm infants have low serum T4 and T3 levels, which may partly explain the immaturity of their tissues. Deiodinase enzymes are important in determining the bioavailability of thyroid hormones: deiodinases D1 and D2 convert T4 to T3, whereas deiodinase D3 inactivates T3 and produces rT3 from T4. In human and ovine fetuses, plasma T3 rises near term in association with the prepartum cortisol surge. This study investigated the developmental effects of cortisol and T3 on tissue deiodinases and plasma thyroid hormones in fetal sheep during late gestation. Plasma cortisol and T3 concentrations in utero were manipulated by exogenous hormone infusion and fetal adrenalectomy. Between 130 and 144 d of gestation (term 145+/-2 d), maturational increments in plasma cortisol and T3, and D1 (hepatic, renal, perirenal adipose tissue) and D3 (cerebral), and decrements in renal and placental D3 activities were abolished by fetal adrenalectomy. Between 125 and 130 d, iv cortisol infusion raised hepatic, renal, and perirenal adipose tissue D1 and reduced renal and placental D3 activities. Infusion with T3 alone increased hepatic D1 and decreased renal D3 activities. Therefore, in the sheep fetus, the prepartum cortisol surge induces tissue-specific changes in deiodinase activity that, by promoting production and suppressing clearance of T3, may be responsible for the rise in plasma T3 concentration near term. Some of the maturational effects of cortisol on deiodinase activity may be mediated by T3.
Collapse
Affiliation(s)
- Alison J Forhead
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3EG, United Kingdom.
| | | | | | | | | |
Collapse
|
47
|
Alenghat T, Yu J, Lazar MA. The N-CoR complex enables chromatin remodeler SNF2H to enhance repression by thyroid hormone receptor. EMBO J 2006; 25:3966-74. [PMID: 16917504 PMCID: PMC1560369 DOI: 10.1038/sj.emboj.7601280] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 07/21/2006] [Indexed: 11/09/2022] Open
Abstract
Unliganded thyroid hormone receptor (TR) actively represses transcription via the nuclear receptor corepressor (N-CoR)/histone deacetylase 3 (HDAC3) complex. Although transcriptional activation by liganded receptors involves chromatin remodeling, the role of ATP-dependent remodeling in receptor-mediated repression is unknown. Here we report that SNF2H, the mammalian ISWI chromatin remodeling ATPase, is critical for repression of a genomically integrated, TR-regulated reporter gene. N-CoR and HDAC3 are both required for recruitment of SNF2H to the repressed gene. SNF2H does not interact directly with the N-CoR/HDAC3 complex, but binds to unacetylated histone H4 tails, suggesting that deacetylase activity of the corepressor complex is critical to SNF2H function. Indeed, HDAC3 as well as SNF2H are required for nucleosomal organization on the TR target gene. Consistent with these findings, reduction of SNF2H induces expression of an endogenous TR-regulated gene, dio1, in liver cells. Thus, although not apparent from studies of transiently transfected reporter genes, gene repression by TR involves the targeting of chromatin remodeling factors to repressed genes by the HDAC activity of nuclear receptor corepressors.
Collapse
Affiliation(s)
- Theresa Alenghat
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine and Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Jiujiu Yu
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine and Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Mitchell A Lazar
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine and Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| |
Collapse
|
48
|
Hashimoto K, Yamada M, Matsumoto S, Monden T, Satoh T, Mori M. Mouse sterol response element binding protein-1c gene expression is negatively regulated by thyroid hormone. Endocrinology 2006; 147:4292-302. [PMID: 16794015 DOI: 10.1210/en.2006-0116] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Sterol regulatory element-binding protein (SREBP)-1c is a key regulator of fatty acid metabolism and plays a pivotal role in the transcriptional regulation of different lipogenic genes mediating lipid synthesis. In previous studies, the regulation of SREBP-1c mRNA levels by thyroid hormone has remained controversial. In this study, we examined whether T3 regulates the mouse SREBP-1c mRNA expression. We found that T3 negatively regulates the mouse SREBP-1c gene expression in the liver, as shown by ribonuclease protection assays and real-time quantitative RT-PCR. Promoter analysis with luciferase assays using HepG2 and Hepa1-6 cells revealed that T3 negatively regulates the mouse SREBP-1c gene promoter (-574 to +42) and that Site2 (GCCTGACAGGTGAAATCGGC) located around the transcriptional start site is responsible for the negative regulation by T3. Gel shift assays showed that retinoid X receptor-alpha/thyroid hormone receptor-beta heterodimer bound to Site2, but retinoid X receptor-alpha/liver X receptor- heterodimer could not bind to the site. In vivo chromatin immunoprecipitation assays demonstrated that T3 induced thyroid hormone receptor-beta recruitment to Site2. Thus, we demonstrated that mouse SREBP-1c mRNA is down-regulated by T3 in vivo and that T3 negatively regulates mouse SREBP-1c gene transcription via a novel negative thyroid hormone response element: Site2.
Collapse
Affiliation(s)
- Koshi Hashimoto
- Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, 3-39-15 Showa-machi Maebashi, Gunma 371-8511, Japan.
| | | | | | | | | | | |
Collapse
|
49
|
Montesinos MM, Pellizas CG, Vélez ML, Susperreguy S, Masini-Repiso AM, Coleoni AH. Thyroid hormone receptor β1 gene expression is increased by Dexamethasone at transcriptional level in rat liver. Life Sci 2006; 78:2584-94. [PMID: 16330054 DOI: 10.1016/j.lfs.2005.10.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Accepted: 10/11/2005] [Indexed: 11/26/2022]
Abstract
Triiodothyronine (T3) exerts most of its effect through nuclear thyroid hormone receptors (TR) which bind mainly as heterodimers with retinoid-X receptors (RXR) to thyroid hormone response elements (TRE) in target genes. It is well known that the synergistic interaction of T3 and glucocorticoids has a role on the synthesis of growth hormone in rat pituitary cell lines and in the T3-induced metamorphosis in amphibians. Glucocorticoids increased mRNAs of T3-regulated hepatic genes. Our laboratory reported increased specific metabolic actions of T3 in rat liver by Dexamethasone (Dex) through a mechanism involving an up-regulation of the maximal binding capacity of TR. In this study we further explored the participation of TR in the molecular mechanism of the Dex-induced increase on liver T3-specific metabolic action. Dex administration to adrenalectomized rats induced an increase of liver TRbeta1 protein and mRNA. Nuclear run-on assay revealed that Dex up-regulated the TR gene transcriptional rate. Transfection assay in COS-7 cells indicated that Dex increased the transcriptional activity of the TRbeta1 promoter. Electrophoretic mobility shift assay demonstrated that Dex induced the binding of additional proteins related to or neighboring the DNA sequence of a glucocorticoid receptor (GR) binding (GRE) half-site in the TRbeta1 promoter. Evidences for an interaction of GR on the TRbeta1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.
Collapse
Affiliation(s)
- M M Montesinos
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
| | | | | | | | | | | |
Collapse
|
50
|
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.
Collapse
Affiliation(s)
- J Köhrle
- Institut für Experimentelle Endokrinologie, Charité, Humboldt Universität zu Berlin, Schumannstrasse 20/21, D-10098 Berlin, Germany.
| | | | | | | |
Collapse
|