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Abstract
The present review traces the road leading to discovery of L-thyroxine, thyroid hormone (3,5,3´-triiodo-L-thyronine, T3) and its cognate nuclear receptors. Thyroid hormone is a pleio-tropic regulator of growth, differentiation, and tissue homeostasis in higher organisms. The major site of the thyroid hormone action is predominantly a cell nucleus. T3 specific binding sites in the cell nuclei have opened a new era in the field of the thyroid hormone receptors (TRs) discovery. T3 actions are mediated by high affinity nuclear TRs, TRalpha and TRbeta, which function as T3-activated transcription factors playing an essential role as transcription-modulating proteins affecting the transcriptional responses in target genes. Discovery and characterization of nuclear retinoid X receptors (RXRs), which form with TRs a heterodimer RXR/TR, positioned RXRs at the epicenter of molecular endocrinology. Transcriptional control via nuclear RXR/TR heterodimer represents a direct action of thyroid hormone. T3 plays a crucial role in the development of brain, it exerts significant effects on the cardiovascular system, skeletal muscle contractile function, bone development and growth, both female and male reproductive systems, and skin. It plays an important role in maintaining the hepatic, kidney and intestine homeostasis and in pancreas, it stimulates the beta-cell proliferation and survival. The TRs cross-talk with other signaling pathways intensifies the T3 action at cellular level. The role of thyroid hormone in human cancers, acting via its cognate nuclear receptors, has not been fully elucidated yet. This review is aimed to describe the history of T3 receptors, starting from discovery of T3 binding sites in the cell nuclei to revelation of T3 receptors as T3-inducible transcription factors in relation to T3 action at cellular level. It also focuses on milestones of investigation, comprising RXR/TR dimerization, cross-talk between T3 receptors, and other regulatory pathways within the cell and mainly on genomic action of T3. This review also focuses on novel directions of investigation on relationships between T3 receptors and cancer. Based on the update of available literature and the author's experimental experience, it is devoted to clinicians and medical students.
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Transcriptional Regulation of the Angptl8 Gene by Hepatocyte Nuclear Factor-1 in the Murine Liver. Sci Rep 2020; 10:9999. [PMID: 32561878 PMCID: PMC7305314 DOI: 10.1038/s41598-020-66570-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 05/20/2020] [Indexed: 01/25/2023] Open
Abstract
Brief refeeding times (~60 min) enhanced hepatic Angptl8 expression in fasted mice. We cloned the mouse Angptl8 promoter region to characterise this rapid refeeding-induced increase in hepatic Angptl8 expression. Deletion of the −309/−60 promoter region significantly attenuated basal promoter activity in hepatocytes. A computational motif search revealed a potential binding motif for hepatocyte nuclear factor 1α/1β (HNF-1α/β) at −84/−68 bp of the promoter. Mutation of the HNF-1 binding site significantly decreased the promoter activity in hepatocytes, and the promoter carrying the mutated HNF-1 site was not transactivated by co-transfection of HNF-1 in a non-hepatic cell line. Silencing Hnf-1 in hepatoma cells and mouse primary hepatocytes reduced Angptl8 protein levels. Electrophoretic mobility-shift assays confirmed direct binding of Hnf-1 to its Angptl8 promoter binding motif. Hnf-1α expression levels increased after short-term refeeding, paralleling the enhanced in vivo expression of the Angptl8 protein. Chromatin immunoprecipitation (ChIP) confirmed the recruitment of endogenous Hnf-1 to the Angptl8 promoter region. Insulin-treated primary hepatocytes showed increased expression of Angptl8 protein, but knockdown of Hnf-1 completely abolished this enhancement. HNF-1 appears to play essential roles in the rapid refeeding-induced increases in Angptl8 expression. HNF-1α may therefore represent a primary medical target for ANGPTL8-related metabolic abnormalities. The study revealed the transcriptional regulation of the mouse hepatic Angptl8 gene by HNF-1.
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Hernandez A. Thyroid Hormone and Alcoholic Fatty Liver: The Developmental Input. Alcohol Clin Exp Res 2019; 43:1834-1837. [PMID: 31283013 DOI: 10.1111/acer.14145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 06/28/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Arturo Hernandez
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, Maine.,Graduate School for Biomedical Science and Engineering, University of Maine, Orono, Maine.,Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts
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Integrating Thyroid Hormone Signaling in Hypothalamic Control of Metabolism: Crosstalk Between Nuclear Receptors. Int J Mol Sci 2018; 19:ijms19072017. [PMID: 29997323 PMCID: PMC6073315 DOI: 10.3390/ijms19072017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/06/2018] [Accepted: 07/06/2018] [Indexed: 12/18/2022] Open
Abstract
The obesity epidemic is well recognized as a significant global health issue. A better understanding of the energy homeostasis mechanisms could help to identify promising anti-obesity therapeutic strategies. It is well established that the hypothalamus plays a pivotal role governing energy balance. The hypothalamus consists of tightly interconnected and specialized neurons that permit the sensing and integration of several peripheral inputs, including metabolic and hormonal signals for an appropriate physiological response. Current evidence shows that thyroid hormones (THs) constitute one of the key endocrine factors governing the regulation and the integration of metabolic homeostasis at the hypothalamic level. THs modulate numerous genes involved in the central control of metabolism, as TRH (Thyrotropin-Releasing Hormone) and MC4R (Melanocortin 4 Receptor). THs act through their interaction with thyroid hormone receptors (TRs). Interestingly, TH signaling, especially regarding metabolic regulations, involves TRs crosstalk with other metabolically linked nuclear receptors (NRs) including PPAR (Peroxisome proliferator-activated receptor) and LXR (Liver X receptor). In this review, we will summarize current knowledge on the important role of THs integration of metabolic pathways in the central regulation of metabolism. Particularly, we will shed light on the crosstalk between TRs and other NRs in controlling energy homeostasis. This could be an important track for the development of attractive therapeutic compounds.
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Lange T, Budde K, Homuth G, Kastenmüller G, Artati A, Krumsiek J, Völzke H, Adamski J, Petersmann A, Völker U, Nauck M, Friedrich N, Pietzner M. Comprehensive Metabolic Profiling Reveals a Lipid-Rich Fingerprint of Free Thyroxine Far Beyond Classic Parameters. J Clin Endocrinol Metab 2018; 103:2050-2060. [PMID: 29546278 DOI: 10.1210/jc.2018-00183] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/07/2018] [Indexed: 02/09/2023]
Abstract
OBJECTIVE Thyroid hormones are ubiquitously involved in human metabolism. However, the precise molecular patterns associated with alterations in thyroid hormones levels remain to be explored in detail. A number of recent studies took great advantage of metabolomics profiling to outline the metabolic actions of thyroid hormones in humans. METHODS Among 952 participants in the Study of Health in Pomerania, data on serum free thyroxine (FT4) and thyrotropin and comprehensive nontargeted metabolomics data from plasma and urine samples were available. Linear regression analyses were performed to assess the association between FT4 or thyrotropin and metabolite levels. RESULTS AND CONCLUSION After accounting for major confounders, 106 of 613 plasma metabolites were significantly associated with FT4. The associations in urine were minor (12 of 587). Most of the plasma metabolites consisted of lipid species, and subsequent analysis of highly resolved lipoprotein subclasses measured by proton nuclear magnetic resonance spectroscopy revealed a consistent decrease in several of these species (e.g., phospholipids) and large low-density lipoprotein and small high-density lipoprotein particles. The latter was unique to men. Several polyunsaturated and saturated fatty acids displayed an association with FT4 in women only. A random forest-based variable selection approach using phenotypic characteristics revealed higher alcohol intake in men and an adverse thyroid state and menopause in women as the putative mediating factors. In general, our observations have confirmed the lipolytic and lipogenic effect of thyroid hormones even in the physiological range and revealed different phenotypic characteristics (e.g., lifestyle differences) as possible confounders for sex-specific findings.
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Affiliation(s)
- Thomas Lange
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Kathrin Budde
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Greifswald, Greifswald, Germany
| | - Georg Homuth
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz Arndt-University Greifswald, Greifswald, Germany
| | - Gabi Kastenmüller
- Institute of Bioinformatics and Systems Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Anna Artati
- Institute of Experimental Genetics, Genome Analysis Center, Helmholtz Zentrum München, Neuherberg, Germany
| | - Jan Krumsiek
- Institute of Computational Biology, Helmholtz Zentrum München, Neuherberg, Germany
- German Centre for Diabetes Research, München-Neuherberg, Germany
| | - Henry Völzke
- German Centre for Cardiovascular Research (DZHK), Partner Site Greifswald, Greifswald, Germany
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
- German Centre for Diabetes Research, Partner Site Greifswald, Greifswald, Germany
| | - Jerzy Adamski
- Institute of Experimental Genetics, Genome Analysis Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Centre for Diabetes Research, München-Neuherberg, Germany
- Lehrstuhl für Experimentelle Genetik, Technische Universität München, Freising-Weihenstephan, Germany
| | - Astrid Petersmann
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Uwe Völker
- German Centre for Cardiovascular Research (DZHK), Partner Site Greifswald, Greifswald, Germany
- Institute of Bioinformatics and Systems Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Matthias Nauck
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Greifswald, Greifswald, Germany
| | - Nele Friedrich
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Greifswald, Greifswald, Germany
| | - Maik Pietzner
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Greifswald, Greifswald, Germany
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Wang Y, Yu X, Zhao QZ, Zheng S, Qing WJ, Miao CD, Sanjay J. Thyroid dysfunction, either hyper or hypothyroidism, promotes gallstone formation by different mechanisms. J Zhejiang Univ Sci B 2017; 17:515-25. [PMID: 27381728 DOI: 10.1631/jzus.b1500210] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have investigated comprehensively the effects of thyroid function on gallstone formation in a mouse model. Gonadectomized gallstone-susceptible male C57BL/6 mice were randomly distributed into three groups each of which received an intervention to induce hyperthyroidism, hypothyroidism, or euthyroidism. After 5 weeks of feeding a lithogenic diet of 15% (w/w) butter fat, 1% (w/w) cholesterol, and 0.5% (w/w) cholic acid, mice were killed for further experiments. The incidence of cholesterol monohydrate crystal formation was 100% in mice with hyperthyroidism, 83% in hypothyroidism, and 33% in euthyroidism, the differences being statistically significant. Among the hepatic lithogenic genes, Trβ was found to be up-regulated and Rxr down-regulated in the mice with hypothyroidism. In contrast, Lxrα, Rxr, and Cyp7α1 were up-regulated and Fxr down-regulated in the mice with hyperthyroidism. In conclusion, thyroid dysfunction, either hyperthyroidism or hypothyroidism, promotes the formation of cholesterol gallstones in C57BL/6 mice. Gene expression differences suggest that thyroid hormone disturbance leads to gallstone formation in different ways. Hyperthyroidism induces cholesterol gallstone formation by regulating expression of the hepatic nuclear receptor genes such as Lxrα and Rxr, which are significant in cholesterol metabolism pathways. However, hypothyroidism induces cholesterol gallstone formation by promoting cholesterol biosynthesis.
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Affiliation(s)
- Yong Wang
- Department of Thyroid Surgery, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Xing Yu
- Cancer Institute, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Qun-Zi Zhao
- Department of Thyroid Surgery, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Shu Zheng
- Cancer Institute, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Wen-Jie Qing
- Department of Clinical Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | - Chun-di Miao
- Department of Clinical Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | - Jaiswal Sanjay
- Department of Clinical Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
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Roman C, Fuior EV, Trusca VG, Kardassis D, Simionescu M, Gafencu AV. Thyroid hormones upregulate apolipoprotein E gene expression in astrocytes. Biochem Biophys Res Commun 2015; 468:190-5. [PMID: 26519880 DOI: 10.1016/j.bbrc.2015.10.132] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 10/24/2015] [Indexed: 11/19/2022]
Abstract
Apolipoprotein E (apoE), a protein mainly involved in lipid metabolism, is associated with several neurodegenerative disorders including Alzheimer's disease. Despite numerous attempts to elucidate apoE gene regulation in the brain, the exact mechanism is still uncovered. The mechanism of apoE gene regulation in the brain involves the proximal promoter and multienhancers ME.1 and ME.2, which evolved by gene duplication. Herein we questioned whether thyroid hormones and their nuclear receptors have a role in apoE gene regulation in astrocytes. Our data showed that thyroid hormones increase apoE gene expression in HTB14 astrocytes in a dose-dependent manner. This effect can be intermediated by the thyroid receptor β (TRβ) which is expressed in these cells. In the presence of triiodothyronine (T3) and 9-cis retinoic acid, in astrocytes transfected to overexpress TRβ and retinoid X receptor α (RXRα), apoE promoter was indirectly activated through the interaction with ME.2. To determine the location of TRβ/RXRα binding site on ME.2, we performed DNA pull down assays and found that TRβ/RXRα complex bound to the region 341-488 of ME.2. This result was confirmed by transient transfection experiments in which a series of 5'- and 3'-deletion mutants of ME.2 were used. These data support the existence of a biologically active TRβ binding site starting at 409 in ME.2. In conclusion, our data revealed that ligand-activated TRβ/RXRα heterodimers bind with high efficiency on tissue-specific distal regulatory element ME.2 and thus modulate apoE gene expression in the brain.
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Affiliation(s)
- Corina Roman
- Institute of Cellular Biology and Pathology "Nicolae Simionescu", Bucharest, Romania
| | - Elena V Fuior
- Institute of Cellular Biology and Pathology "Nicolae Simionescu", Bucharest, Romania
| | - Violeta G Trusca
- Institute of Cellular Biology and Pathology "Nicolae Simionescu", Bucharest, Romania
| | - Dimitris Kardassis
- University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, Crete, Greece
| | - Maya Simionescu
- Institute of Cellular Biology and Pathology "Nicolae Simionescu", Bucharest, Romania
| | - Anca V Gafencu
- Institute of Cellular Biology and Pathology "Nicolae Simionescu", Bucharest, Romania.
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Emerging regulation and function of betatrophin. Int J Mol Sci 2014; 15:23640-57. [PMID: 25530616 PMCID: PMC4284785 DOI: 10.3390/ijms151223640] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/30/2014] [Accepted: 12/12/2014] [Indexed: 02/06/2023] Open
Abstract
Betatrophin, also known as TD26/RIFL/lipasin/ANGPTL8/C19orf80, is a novel protein predominantly expressed in human liver. To date, several betatrophin orthologs have been identified in mammals. Increasing evidence has revealed an association between betatrophin expression and serum lipid profiles, particularly in patients with obesity or diabetes. Stimulators of betatrophin, such as insulin, thyroid hormone, irisin and caloric intake, are usually relevant to energy expenditure or thermogenesis. In murine models, serum triglyceride levels as well as pancreatic cell proliferation are potently enhanced by betatrophin. Intriguingly, conflicting phenomena have also been reported that betatrophin suppresses hepatic triglyceride levels, suggesting that betatrophin function is mediated by complex regulatory processes. However, its precise physiological role remains unclear at present. In this review, we have summarized the current findings on betatrophin and their implications.
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Sinha RA, Singh BK, Yen PM. Thyroid hormone regulation of hepatic lipid and carbohydrate metabolism. Trends Endocrinol Metab 2014; 25:538-45. [PMID: 25127738 DOI: 10.1016/j.tem.2014.07.001] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 06/21/2014] [Accepted: 07/07/2014] [Indexed: 02/07/2023]
Abstract
Thyroid hormone (TH) has important roles in regulating hepatic lipid, cholesterol, and glucose metabolism. Recent findings suggest that clinical conditions such as non-alcoholic fatty liver disease and type 2 diabetes mellitus, which are associated with dysregulated hepatic metabolism, may involve altered intracellular TH action. In addition, TH has key roles in lipophagy in lipid metabolism, mitochondrial quality control, and the regulation of metabolic genes. In this review, we discuss recent findings regarding the functions of TH in hepatic metabolism, the relationship between TH and metabolic disorders, and the potential therapeutic use of thyromimetics to treat metabolic dysfunction in the liver.
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Affiliation(s)
- Rohit A Sinha
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169547, Singapore
| | - Brijesh K Singh
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169547, Singapore
| | - Paul M Yen
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169547, Singapore; Sarah W. Stedman Nutrition and Metabolism Center, Departments of Medicine and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27705, USA.
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Parikh M, Patel K, Soni S, Gandhi T. Liver X Receptor: A Cardinal Target for Atherosclerosis and Beyond. J Atheroscler Thromb 2014. [DOI: 10.5551/jat.19778] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Wu SM, Cheng WL, Lin CD, Lin KH. Thyroid hormone actions in liver cancer. Cell Mol Life Sci 2013; 70:1915-36. [PMID: 22955376 PMCID: PMC11113324 DOI: 10.1007/s00018-012-1146-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 08/06/2012] [Accepted: 08/20/2012] [Indexed: 12/13/2022]
Abstract
The thyroid hormone 3,3',5-triiodo-L-thyronine (T3) mediates several physiological processes, including embryonic development, cellular differentiation, metabolism, and the regulation of cell proliferation. Thyroid hormone receptors (TRs) generally act as heterodimers with the retinoid X receptor (RXR) to regulate target genes. In addition to their developmental and metabolic functions, TRs have been shown to play a tumor suppressor role, suggesting that their aberrant expression can lead to tumor transformation. Conversely, recent reports have shown an association between overexpression of wild-type TRs and tumor metastasis. Signaling crosstalk between T3/TR and other pathways or specific TR coregulators appear to affect tumor development. Since TR actions are complex as well as cell context-, tissue- and time-specific, aberrant expression of the various TR isoforms has different effects during diverse tumorigenesis. Therefore, elucidation of the T3/TR signaling mechanisms in cancers should facilitate the identification of novel therapeutic targets. This review provides a summary of recent studies focusing on the role of TRs in hepatocellular carcinomas (HCCs).
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Affiliation(s)
- Sheng-Ming Wu
- Department of Biochemistry, College of Medicine, Chang-Gung University, 259 Wen-hwa 1 Road, Taoyuan, 333 Taiwan
| | - Wan-Li Cheng
- Department of Biochemistry, College of Medicine, Chang-Gung University, 259 Wen-hwa 1 Road, Taoyuan, 333 Taiwan
| | - Crystal D. Lin
- Pre-med Program, Pacific Union College, Angwin, CA 94508 USA
| | - Kwang-Huei Lin
- Department of Biochemistry, College of Medicine, Chang-Gung University, 259 Wen-hwa 1 Road, Taoyuan, 333 Taiwan
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Ishida E, Hashimoto K, Okada S, Satoh T, Yamada M, Mori M. Crosstalk between thyroid hormone receptor and liver X receptor in the regulation of selective Alzheimer's disease indicator-1 gene expression. PLoS One 2013; 8:e54901. [PMID: 23359226 PMCID: PMC3554671 DOI: 10.1371/journal.pone.0054901] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 12/17/2012] [Indexed: 11/29/2022] Open
Abstract
Selective Alzheimer’s disease (AD) indicator 1 (Seladin-1) has been identified as a gene down-regulated in the degenerated lesions of AD brain. Up-regulation of Seladin-1 reduces the accumulation of β-amyloid and neuronal death. Thyroid hormone (TH) exerts an important effect on the development and maintenance of central nervous systems. In the current study, we demonstrated that Seladin-1 gene and protein expression in the forebrain was increased in thyrotoxic mice compared with that of euthyroid mice. However, unexpectedly, no significant decrease in the gene and protein expression was observed in hypothyroid mice. Interestingly, an agonist of liver X receptor (LXR), TO901317 (TO) administration in vivo increased Seladin-1 gene and protein expression in the mouse forebrain only in a hypothyroid state and in the presence of mutant TR-β, suggesting that LXR-α would compensate for TR-β function to maintain Seladin-1 gene expression in hypothyroidism and resistance to TH. TH activated the mouse Seladin-1 gene promoter (−1936/+21 bp) and site 2 including canonical TH response element (TRE) half-site in the region between −159 and −154 bp is responsible for the positive regulation. RXR-α/TR-β heterodimerization was identified on site 2 by gel-shift assay, and chromatin immunoprecipitation assay revealed the recruitment of TR-β to site 2 and the recruitment was increased upon TH administration. On the other hand, LXR-α utilizes a distinct region from site 2 (−120 to −102 bp) to activate the mouse Seladin-1 gene promoter. Taking these findings together, we concluded that TH up-regulates Seladin-1 gene expression at the transcriptional level and LXR-α maintains the gene expression.
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Affiliation(s)
- Emi Ishida
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Koshi Hashimoto
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
- * E-mail:
| | - Shuichi Okada
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Tetsurou Satoh
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Masanobu Yamada
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Masatomo Mori
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
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Hashimoto K, Mori M. [Endocrine disease: progress in diagnosis and treatment. Topics: II. Progress in treatment: 4. Thyroid hormone and lipid metabolism: novel thyroid hormone receptor beta1 selective thyroid hormone analogs]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 2012; 101:1000-1006. [PMID: 22730728 DOI: 10.2169/naika.101.1000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- Koshi Hashimoto
- Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Japan
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