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Bering T, Hertz H, Rath MF. The Circadian Oscillator of the Cerebellum: Triiodothyronine Regulates Clock Gene Expression in Granule Cells in vitro and in the Cerebellum of Neonatal Rats in vivo. Front Physiol 2021; 12:706433. [PMID: 34776993 PMCID: PMC8578874 DOI: 10.3389/fphys.2021.706433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022] Open
Abstract
The central circadian clock resides in the suprachiasmatic nucleus (SCN) of the hypothalamus, but an SCN-dependent molecular circadian oscillator is present in the cerebellar cortex. Recent findings suggest that circadian release of corticosterone is capable of driving the circadian oscillator of the rat cerebellum. To determine if additional neuroendocrine signals act to shape cerebellar clock gene expression, we here tested the role of the thyroid hormone triiodothyronine (T3) in regulation of the cerebellar circadian oscillator. In cultured cerebellar granule cells from mixed-gender neonatal rats, T3 treatment affected transcript levels of the clock genes Per2, Arntl, Nr1d1, and Dbp, suggesting that T3 acts directly on granule cells to control the circadian oscillator. We then used two different in vivo protocols to test the role of T3 in adult female rats: Firstly, a single injection of T3 did not influence clock gene expression in the cerebellum. Secondly, we established a surgical rat model combining SCN lesion with a programmable micropump infusing circadian physiological levels of T3; however, rhythmic infusion of T3 did not reestablish differential clock gene expression between day and night in SCN lesioned rats. To test if the effects of T3 observed in vitro were related to the developmental stage, acute injections of T3 were performed in mixed-gender neonatal rats in vivo; this procedure significantly affected cerebellar expression of the clock genes Per1, Per2, Nr1d1, and Dbp. Developmental comparisons showed rhythmic expression of all clock genes analyzed in the cerebellum of adult rats only, whereas T3 responsiveness was limited to neonatal animals. Thus, T3 shapes cerebellar clock gene profiles in early postnatal stages, but it does not represent a systemic circadian regulatory mechanism linking the SCN to the cerebellum throughout life.
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Affiliation(s)
- Tenna Bering
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Hertz
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin Fredensborg Rath
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Egri P, Fekete C, Dénes Á, Reglődi D, Hashimoto H, Fülöp BD, Gereben B. Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Regulates the Hypothalamo-Pituitary-Thyroid (HPT) Axis via Type 2 Deiodinase in Male Mice. Endocrinology 2016; 157:2356-66. [PMID: 27046436 DOI: 10.1210/en.2016-1043] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The hypothalamic activation of thyroid hormones by type 2 deiodinase (D2), catalyzing the conversion of thyroxine to T3, is critical for the proper function of the hypothalamo-pituitary-thyroid (HPT) axis. Regulation of D2 expression in tanycytes alters the activity of the HPT axis. However, signals that regulate D2 expression in tanycytes are poorly understood. The pituitary adenylate cyclase-activating polypeptide (PACAP) increases intracellular cAMP level, a second messenger known to stimulate the DIO2 gene; however, its importance in tanycytes is not completely characterized. Therefore, we tested whether this ubiquitously expressed neuropeptide regulates the HPT axis through stimulation of D2 in tanycytes. PACAP increased the activity of human DIO2 promoter in luciferase reporter assay that was abolished by mutation of cAMP-response element. Furthermore, PAC1R receptor immunoreactivity was identified in hypothalamic tanycytes, suggesting that these D2-expressing cells could be regulated by PACAP. Intracerebroventricular PACAP administration resulted in increased D2 activity in the mediobasal hypothalamus, suppressed Trh expression in the hypothalamic paraventricular nucleus, and decreased Tshb expression in the pituitary demonstrating that PACAP affects the D2-mediated control of the HPT axis. To understand the role of endogenous PACAP in the regulation of HPT axis, the effect of decreased PACAP expression was studied in heterozygous Adcyap1 (PACAP) knockout mice. These animals were hypothyroid that may be the consequence of altered hypothalamic T3 degradation during set-point formation of the HPT axis. In conclusion, PACAP is an endogenous regulator of the HPT axis by affecting T3-mediated negative feedback via cAMP-induced D2 expression of tanycytes.
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Affiliation(s)
- P Egri
- Department of Endocrine Neurobiology (P.E., C.F., B.G.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; János Szentágothai PhD School of Neurosciences (P.E.), Semmelweis University, Budapest H-1085, Hungary; Department of Medicine (C.F.), Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts 02111; Department of Gene Technology and Developmental Neurobiology (Á.D.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; Department of Anatomy (D.R., B.D.F.), University of Pécs Medical School, Pécs H-7624, Hungary; and Laboratory of Molecular Neuropharmacology (H.H.) and iPS Cell-Based Research Project on Brain Neuropharmacology and Toxicology (H.H.), Graduate School of Pharmaceutical Sciences, Osaka University, and Molecular Research Center for Children's Mental Development H.H.), United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Suita, Osaka 565-0871, Japan
| | - C Fekete
- Department of Endocrine Neurobiology (P.E., C.F., B.G.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; János Szentágothai PhD School of Neurosciences (P.E.), Semmelweis University, Budapest H-1085, Hungary; Department of Medicine (C.F.), Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts 02111; Department of Gene Technology and Developmental Neurobiology (Á.D.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; Department of Anatomy (D.R., B.D.F.), University of Pécs Medical School, Pécs H-7624, Hungary; and Laboratory of Molecular Neuropharmacology (H.H.) and iPS Cell-Based Research Project on Brain Neuropharmacology and Toxicology (H.H.), Graduate School of Pharmaceutical Sciences, Osaka University, and Molecular Research Center for Children's Mental Development H.H.), United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Suita, Osaka 565-0871, Japan
| | - Á Dénes
- Department of Endocrine Neurobiology (P.E., C.F., B.G.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; János Szentágothai PhD School of Neurosciences (P.E.), Semmelweis University, Budapest H-1085, Hungary; Department of Medicine (C.F.), Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts 02111; Department of Gene Technology and Developmental Neurobiology (Á.D.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; Department of Anatomy (D.R., B.D.F.), University of Pécs Medical School, Pécs H-7624, Hungary; and Laboratory of Molecular Neuropharmacology (H.H.) and iPS Cell-Based Research Project on Brain Neuropharmacology and Toxicology (H.H.), Graduate School of Pharmaceutical Sciences, Osaka University, and Molecular Research Center for Children's Mental Development H.H.), United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Suita, Osaka 565-0871, Japan
| | - D Reglődi
- Department of Endocrine Neurobiology (P.E., C.F., B.G.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; János Szentágothai PhD School of Neurosciences (P.E.), Semmelweis University, Budapest H-1085, Hungary; Department of Medicine (C.F.), Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts 02111; Department of Gene Technology and Developmental Neurobiology (Á.D.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; Department of Anatomy (D.R., B.D.F.), University of Pécs Medical School, Pécs H-7624, Hungary; and Laboratory of Molecular Neuropharmacology (H.H.) and iPS Cell-Based Research Project on Brain Neuropharmacology and Toxicology (H.H.), Graduate School of Pharmaceutical Sciences, Osaka University, and Molecular Research Center for Children's Mental Development H.H.), United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Suita, Osaka 565-0871, Japan
| | - H Hashimoto
- Department of Endocrine Neurobiology (P.E., C.F., B.G.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; János Szentágothai PhD School of Neurosciences (P.E.), Semmelweis University, Budapest H-1085, Hungary; Department of Medicine (C.F.), Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts 02111; Department of Gene Technology and Developmental Neurobiology (Á.D.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; Department of Anatomy (D.R., B.D.F.), University of Pécs Medical School, Pécs H-7624, Hungary; and Laboratory of Molecular Neuropharmacology (H.H.) and iPS Cell-Based Research Project on Brain Neuropharmacology and Toxicology (H.H.), Graduate School of Pharmaceutical Sciences, Osaka University, and Molecular Research Center for Children's Mental Development H.H.), United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Suita, Osaka 565-0871, Japan
| | - B D Fülöp
- Department of Endocrine Neurobiology (P.E., C.F., B.G.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; János Szentágothai PhD School of Neurosciences (P.E.), Semmelweis University, Budapest H-1085, Hungary; Department of Medicine (C.F.), Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts 02111; Department of Gene Technology and Developmental Neurobiology (Á.D.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; Department of Anatomy (D.R., B.D.F.), University of Pécs Medical School, Pécs H-7624, Hungary; and Laboratory of Molecular Neuropharmacology (H.H.) and iPS Cell-Based Research Project on Brain Neuropharmacology and Toxicology (H.H.), Graduate School of Pharmaceutical Sciences, Osaka University, and Molecular Research Center for Children's Mental Development H.H.), United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Suita, Osaka 565-0871, Japan
| | - Balázs Gereben
- Department of Endocrine Neurobiology (P.E., C.F., B.G.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; János Szentágothai PhD School of Neurosciences (P.E.), Semmelweis University, Budapest H-1085, Hungary; Department of Medicine (C.F.), Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts 02111; Department of Gene Technology and Developmental Neurobiology (Á.D.), Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest H-1083, Hungary; Department of Anatomy (D.R., B.D.F.), University of Pécs Medical School, Pécs H-7624, Hungary; and Laboratory of Molecular Neuropharmacology (H.H.) and iPS Cell-Based Research Project on Brain Neuropharmacology and Toxicology (H.H.), Graduate School of Pharmaceutical Sciences, Osaka University, and Molecular Research Center for Children's Mental Development H.H.), United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Suita, Osaka 565-0871, Japan
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Chik CL, Price DM, Ho AK. Histone modifications on the adrenergic induction of type II deiodinase in rat pinealocytes. Mol Cell Endocrinol 2011; 343:63-70. [PMID: 21704117 DOI: 10.1016/j.mce.2011.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/02/2011] [Accepted: 06/09/2011] [Indexed: 10/18/2022]
Abstract
Histone modifications have been shown to play an important role in regulating gene expression. In this study, we investigated the impact of histone modifications on the adrenergic-regulated transcription of type 2 deiodinase (Dio2), a CREB-target gene in the rat pinealocyte. Treatment of pinealocytes with inhibitors of aurora C, a histone kinase, resulted in an inhibitory effect on the adrenergic-stimulated histone H3 Ser10 phosphorylation and Dio2 transcription. Given the established link between histone phosphorylation and acetylation, the role of histone acetylation on the adrenergic-induced Dio2 transcription was investigated. Treatment of pinealocytes with histone deacetylase inhibitors inhibited the adrenergic-induced Dio2 transcription. Chromatin immunoprecipitation with antibodies against acetylated Lys14 of H3 showed an increase in DNA recovery of the promoter region of Dio2 following treatment with trichostatin A. Together, our results indicate that, beside activation of CREB, epigenetic factors such as histone modifications also play an important role in regulating Dio2 transcription.
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Affiliation(s)
- Constance L Chik
- Department of Medicine (CLC) and Department of Physiology (DMP, AKH), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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Toyoda N, Yasuzawa-Amano S, Nomura E, Yamauchi A, Nishimura K, Ukita C, Morimoto S, Kosaki A, Iwasaka T, Harney JW, Larsen PR, Nishikawa M. Thyroid hormone activation in vascular smooth muscle cells is negatively regulated by glucocorticoid. Thyroid 2009; 19:755-63. [PMID: 19508118 PMCID: PMC2857441 DOI: 10.1089/thy.2009.0044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Type 2 iodothyronine deiodinase (D2) catalyzes the production of triiodothyronine from thyroxine. D2 is present in rat aorta media, and there is a circadian variation in the D2 expression. In rat aorta media, the D2 activity exhibited the maximal value at 1200 hour and low value between 1800 and 2400 hour. To understand the mechanisms that induce the circadian variation in the D2 expression, we examined the effects of glucocorticoid on the D2 activity and mRNA in rat aorta media and cultured vascular smooth muscle cells (VSMCs). METHODS The effects of intrinsic and extrinsic glucocorticoid on the D2 activity and mRNA in rat aorta media were studied using metyrapone, a corticosterone synthesis inhibitor, and dexamethasone (DEX). Further, the effects of DEX on D2 expression were studied using the cultured rat VSMCs. RESULTS The trough values of D2 activity and mRNA at 2100 hour were increased by the treatment with metyrapone. On the other hand, the peak values of D2 activity and mRNA were decreased by the treatment with DEX. D2 activity and mRNA in cultured rat VSMCs were increased by the addition of 10(-3) M dibutyryl cyclic adenosine monophosphate [(Bu)(2)cAMP]. The increments were reduced by coincubation with 10(-6) M DEX. CONCLUSIONS These results suggest that glucocorticoids might directly suppress the D2 expression in rat VSMCs induced by a cAMP-dependent mechanism.
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Affiliation(s)
- Nagaoki Toyoda
- Department of Internal Medicine II, Kansai Medical University, Hirakata-City, Osaka, Japan.
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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.
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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
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Gereben B, Zavacki AM, Ribich S, Kim BW, Huang SA, Simonides WS, Zeöld A, Bianco AC. Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling. Endocr Rev 2008; 29:898-938. [PMID: 18815314 PMCID: PMC2647704 DOI: 10.1210/er.2008-0019] [Citation(s) in RCA: 563] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 08/15/2008] [Indexed: 02/06/2023]
Abstract
The iodothyronine deiodinases initiate or terminate thyroid hormone action and therefore are critical for the biological effects mediated by thyroid hormone. Over the years, research has focused on their role in preserving serum levels of the biologically active molecule T(3) during iodine deficiency. More recently, a fascinating new role of these enzymes has been unveiled. The activating deiodinase (D2) and the inactivating deiodinase (D3) can locally increase or decrease thyroid hormone signaling in a tissue- and temporal-specific fashion, independent of changes in thyroid hormone serum concentrations. This mechanism is particularly relevant because deiodinase expression can be modulated by a wide variety of endogenous signaling molecules such as sonic hedgehog, nuclear factor-kappaB, growth factors, bile acids, hypoxia-inducible factor-1alpha, as well as a growing number of xenobiotic substances. In light of these findings, it seems clear that deiodinases play a much broader role than once thought, with great ramifications for the control of thyroid hormone signaling during vertebrate development and metamorphosis, as well as injury response, tissue repair, hypothalamic function, and energy homeostasis in adults.
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Affiliation(s)
- Balázs Gereben
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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Meyer ELS, Goemann IM, Dora JM, Wagner MS, Maia AL. Type 2 iodothyronine deiodinase is highly expressed in medullary thyroid carcinoma. Mol Cell Endocrinol 2008; 289:16-22. [PMID: 18514391 PMCID: PMC2527534 DOI: 10.1016/j.mce.2008.04.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 03/08/2008] [Accepted: 04/14/2008] [Indexed: 10/22/2022]
Abstract
Type II deiodinase (D2) plays a critical role in controlling intracellular T3 concentration and early studies indicated a follicular but not a parafollicular C-cell origin of D2 activity in the thyroid gland. Here, we show that D2 is highly expressed in human medullary thyroid carcinoma (MTC), a tumor that arises from the C-cells. D2 transcripts were detected in all MTC samples obtained from 12 unselected MTC patients and the levels of D2 activity were comparable to those found in surrounding normal follicular tissue (0.41+/-0.10 fmol min mg protein vs. 0.43+/-0.41 fmol min mg protein, P=0.91). Additional analysis in the TT cells, a human MTC cell line, demonstrated that the D2 expression is downregulated by thyroid hormones and enhanced by cAMP analogs and dexamethasone. The thyroid hormone receptor alpha1 and beta isoforms were also detected in all MTC samples and in TT cells, thus suggesting a potential role of T3 locally produced by D2 in this neoplastic tissue.
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Affiliation(s)
- Erika L Souza Meyer
- Thyroid Section, Endocrinology Division, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos, 2350, 90035-003 Porto Alegre, RS, Brazil
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Fukuhara C, Tosini G. Analysis of daily and circadian gene expression in the rat pineal gland. Neurosci Res 2007; 60:192-8. [PMID: 18067983 DOI: 10.1016/j.neures.2007.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Revised: 10/22/2007] [Accepted: 10/26/2007] [Indexed: 11/27/2022]
Abstract
The mammalian pineal gland is an important component of the circadian system. In the present study, we examined the expression of roughly 8000 genes in the rat pineal gland as a function of time of day under light-dark (LD) cycles and in constant dark (DD) using oligo DNA microarray technique. We identified 47 and 13 genes that showed higher levels at night and day, respectively, under LD. The same patterns of expression were also observed in DD. About half of the genes that peaked at night have a known biological function, i.e., transcription factors and proteins that are involved in signaling cascades, whereas 14 are expressed sequence tags and 8 have an unknown biological function. Twelve of the genes that were up-regulated at night were also up-regulated after 1h NE stimulation, thus suggesting that the expression of these genes is controlled by adrenergic mechanisms. Of the 13 genes that were up-regulated in the daytime, 6 coded for proteins that are involved in intracellular signaling pathways. The results obtained with microarray analysis were well correlated with data obtained using real time quantitative RT-PCR. The present results provide new materials to dissect and understand the pineal physiology.
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Affiliation(s)
- Chiaki Fukuhara
- Neuroscience Institute and NSF Center for Behavioral Neuroscience, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310-1495, USA.
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Chik CL, Wloka MT, Price DM, Ho AK. The role of repressor proteins in the adrenergic induction of type II iodothyronine deiodinase in rat pinealocytes. Endocrinology 2007; 148:3523-31. [PMID: 17446180 DOI: 10.1210/en.2007-0166] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this study, we investigated the transcriptional regulation of the adrenergic induction of type II iodothyronine deiodinase (Dio2) in rat pinealocytes. Treatment of pinealocytes with norepinephrine (NE) caused an increase in the mRNA level of Dio2 that peaked around 2 h and declined over the next 5 h. Both beta- and alpha1-adrenergic receptors contributed to the NE induction of Dio2 expression through a cAMP/protein kinase A mechanism. In pinealocytes that had been stimulated by NE, inhibition of transcription by actinomycin had no discernible effect on Dio2 expression. In contrast, inhibition of protein synthesis by cycloheximide enhanced the NE induction of Dio2 expression, suggesting the involvement of a repressor protein. Transient transfection of pinealocytes with adenovirus expressing small interfering RNA against Fos-related antigen 2 (Fra2) enhanced the NE induction of Dio2 expression, whereas the effect of overexpression of the full-length transcript of Fra2 was inhibitory. Time-course study indicated that preventing the NE induction of Fra2 enhanced the NE induction of Dio2 after 3 h, and the enhancement persisted beyond 6 h after NE stimulation. In comparison, transient transfection of pinealocytes with small interfering RNA against inducible cAMP early repressor (Icer) had no effect on the NE induction of Dio2 expression, whereas overexpression of the full-length transcript of Icer caused a small reduction of the NE-stimulated Dio2 expression. Together, our results support Fra-2 as an important transcriptional repressor that helps shape the time profile of the adrenergic induction of Dio2 expression in the rat pineal gland.
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Affiliation(s)
- C L Chik
- Department of Physiology, Faculty of Medicine and Dentistry, 7-26 Medical Sciences Building, Edmonton, University of Alberta, Canada T6G 2H7
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Abstract
Recent identification of new selenocysteine-containing proteins has revealed relationships between the two trace elements selenium (Se) and iodine and the hormone network. Several selenoproteins participate in the protection of thyrocytes from damage by H(2)O(2) produced for thyroid hormone biosynthesis. Iodothyronine deiodinases are selenoproteins contributing to systemic or local thyroid hormone homeostasis. The Se content in endocrine tissues (thyroid, adrenals, pituitary, testes, ovary) is higher than in many other organs. Nutritional Se depletion results in retention, whereas Se repletion is followed by a rapid accumulation of Se in endocrine tissues, reproductive organs, and the brain. Selenoproteins such as thioredoxin reductases constitute the link between the Se metabolism and the regulation of transcription by redox sensitive ligand-modulated nuclear hormone receptors. Hormones and growth factors regulate the expression of selenoproteins and, conversely, Se supply modulates hormone actions. Selenoproteins are involved in bone metabolism as well as functions of the endocrine pancreas and adrenal glands. Furthermore, spermatogenesis depends on adequate Se supply, whereas Se excess may impair ovarian function. Comparative analysis of the genomes of several life forms reveals that higher mammals contain a limited number of identical genes encoding newly detected selenocysteine-containing proteins.
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Affiliation(s)
- J Köhrle
- Institut für Experimentelle Endokrinologie, Charité, Humboldt Universität zu Berlin, Schumannstrasse 20/21, D-10098 Berlin, Germany.
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Morimura T, Tsunekawa K, Kasahara T, Seki K, Ogiwara T, Mori M, Murakami M. Expression of type 2 iodothyronine deiodinase in human osteoblast is stimulated by thyrotropin. Endocrinology 2005; 146:2077-84. [PMID: 15650076 DOI: 10.1210/en.2004-1432] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Thyroid hormones play important roles in bone growth, development, and turnover. To exert its biological activity, T(4) needs to be converted to T(3) by iodothyronine deiodinase. In human thyroid gland as well as rat brown adipose tissue, type 2 iodothyronine deiodinase (D2) expression is regulated by a TSH receptor-cAMP-mediated mechanism. TSH receptor knockout mice demonstrated the direct effects of TSH on bone via TSH receptors found on osteoblast and osteoclast precursors. In the present study we investigated the possible expression and function of iodothyronine deiodinase and TSH receptors in human osteoblast-like osteosarcoma (SaOS-2) cells and normal human osteoblast (NHOst) cells. Iodothyronine deiodinase activity was detected in SaOS-2 cells and NHOst cells, and all of the characteristics of deiodinating activity were compatible with those of D2. Northern analysis demonstrated D2 mRNA expression in SaOS-2 cells and NHOst cells. D2 mRNA levels as well as D2 activities were rapidly increased by dibutyryl cAMP or forskolin in SaOS-2 cells and NHOst cells. TSH receptor mRNA was demonstrated in SaOS-2 cells and NHOst cells, and D2 mRNA and D2 activity were stimulated by TSH in both cells. In addition, all T(3) receptor isoforms were detected by RT-PCR in SaOS-2 cells and NHOst cells. The present results indicate the expression of functional TSH receptors and D2 in human osteoblasts and suggest previously unrecognized roles of TSH receptors and local T(3) production by D2 in the pathophysiology of human osteoblasts.
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Affiliation(s)
- Tadashi Morimura
- Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan
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Kalsbeek A, Buijs RM, van Schaik R, Kaptein E, Visser TJ, Doulabi BZ, Fliers E. Daily variations in type II iodothyronine deiodinase activity in the rat brain as controlled by the biological clock. Endocrinology 2005; 146:1418-27. [PMID: 15550511 DOI: 10.1210/en.2004-0763] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Type II deiodinase (D2) plays a key role in regulating thyroid hormone-dependent processes in, among others, the central nervous system (CNS) by accelerating the intracellular conversion of T4 into active T3. Just like the well-known daily rhythm of the hormones of the hypothalamo-pituitary-thyroid axis, D2 activity also appears to show daily variations. However, the mechanisms involved in generating these daily variations, especially in the CNS, are not known. Therefore, we decided to investigate the role the master biological clock, located in the hypothalamus, plays with respect to D2 activity in the rat CNS as well as the role of one of its main hormonal outputs, i.e. plasma corticosterone. D2 activity showed a significant daily rhythm in the pineal and pituitary gland as well as hypothalamic and cortical brain tissue, albeit with a different timing of its acrophase in the different tissues. Ablation of the biological clock abolished the daily variations of D2 activity in all four tissues studied. The main effect of the knockout of the suprachiasmatic nuclei (SCN) was a reduction of nocturnal peak levels in D2 activity. Moreover, contrary to previous observations in SCN-intact animals, in SCN-lesioned animals, the decreased levels of D2 activity are accompanied by decreased plasma levels of the thyroid hormones, suggesting that the SCN separately stimulates D2 activity as well as the hypothalamo-pituitary-thyroid axis.
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Affiliation(s)
- Andries Kalsbeek
- Netherlands Institute for Brain Research, Department of Endocrinology and Metabolism, 1105 AZ Amsterdam, The Netherlands.
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13
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Araki O, Morimura T, Ogiwara T, Mizuma H, Mori M, Murakami M. Expression of type 2 iodothyronine deiodinase in corticotropin-secreting mouse pituitary tumor cells is stimulated by glucocorticoid and corticotropin-releasing hormone. Endocrinology 2003; 144:4459-65. [PMID: 12960076 DOI: 10.1210/en.2003-0419] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We identified the presence of iodothyronine deiodinase in AtT-20 mouse pituitary tumor cells that secrete corticotropin. Iodothyronine deiodinating activity in AtT-20 cells fulfills all the characteristics of type 2 iodothyronine deiodinase (D2), including the inhibition by thyroid hormones, the insensitivity to inhibition by 6-propyl-2-thiouracil, and the low Michaelis-Menten constant value for T4. Northern analysis using mouse D2 cRNA probe demonstrated the hybridization signal of approximately 7.0 kb in size in AtT-20 cells. D2 activity and D2 mRNA were stimulated by glucocorticoid in a dose-dependent manner but were not stimulated by testosterone or beta-estradiol. D2 expression was stimulated by (Bu)2cAMP, and CRH in a dose-dependent manner in the presence of dexamethasone. These results suggest the previously unrecognized role of local thyroid hormone activation by D2 in the regulation of pituitary corticotrophs.
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Affiliation(s)
- Osamu Araki
- First Department of Internal Medicine, Gunma University School of Medicine, Maebashi 371-8511, Japan
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14
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Guillaumond F, Becquet D, Bosler O, François-Bellan AM. Adrenergic inducibility of AP-1 binding in the rat pineal gland depends on prior photoperiod. J Neurochem 2002; 83:157-66. [PMID: 12358739 DOI: 10.1046/j.1471-4159.2002.01140.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The main known function of the pineal gland in mammals is the temporal synchronization of physiological rhythms to seasonal changes of day length (photoperiod). In rat, the transcription factor activating protein-1 (AP-1) displays a circadian rhythm in its DNA binding in the pineal gland, which results from the rhythmic expression of Fra-2. We postulated that, if AP-1 is an important component of pineal gland functioning, then variations in photoperiodic conditions should lead to an adaptation of the AP-1 binding rhythm. Here we show that AP-1 binding patterns adapt to variations in lighting conditions, in the same way as the rhythm of arylalkylamine-N-acetyltransferase (AA-NAT) activity. This adaptation appeared to result from photoperiodic adaptation of the rhythmic fra-2 gene expression and was reflected by an adapted delay between the onset of night and the acrophase of the nocturnal peak. We further showed that photoperiodic adaptation of both the AP-1 binding and AA-NAT activity rhythms resulted from adapted changes in adrenergic inducibility of both variables at night onset. We finally provided evidence that AP-1 shared with the CREM gene encoding the transcriptional repressor protein inducible cAMP early repressor (ICER) the ability to be hypersensitive or subsensitive to adrenergic stimuli, depending on prior photoperiod.
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Affiliation(s)
- F Guillaumond
- Institut Fédératif Jean-Roche, Faculté de Médecine Nord, Université de la Méditerranée, Boulevard Pierre Dramard, 13916 Marseille cedex 20, France
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15
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Gereben B, Kollár A, Harney JW, Larsen PR. The mRNA structure has potent regulatory effects on type 2 iodothyronine deiodinase expression. Mol Endocrinol 2002; 16:1667-79. [PMID: 12089359 DOI: 10.1210/mend.16.7.0879] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Type 2 deiodinase (D2) is a selenoenzyme catalyzing the activation of T(4) to T(3). D2 activity/mRNA ratios are often low, suggesting that there is significant posttranscriptional regulation. The D2 mRNA in higher vertebrates is more than 6 kb, containing long 5' and 3' untranslated regions (UTRs). The D2 5'UTRs are greater than 600 nucleotides and contain 3-5 short open reading frames. These full-length 5'UTRs reduce the D2 translation efficiency approximately 5-fold. The inhibition by human D2 5'UTR is localized to a region containing the first short open reading frame encoding a tripeptide-MKG. This inhibition was abolished by mutating the AUG start codon and weakened by modification of the essential purine of the Kozak consensus. Deletion of the 3.7-kb 3'UTR of the chicken D2 mRNA increased D2 activity approximately 3.8-fold due to an increase in D2 mRNA half-life. In addition, alternatively spliced D2 mRNA transcripts similar in size to the major 6- to 7-kb D2 mRNAs but not encoding an active enzyme are present in both human and chicken tissues. Our results indicate that a number of factors reduce the D2 protein levels. These mechanisms, together with the short half-life of the protein, ensure limited expression of this key regulator of T(4) activation.
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Affiliation(s)
- Balázs Gereben
- Institute of Experimental Medicine, Department of Neurobiology, Budapest H-1083, Hungary
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16
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Martinez-deMena R, Hernández A, Obregón MJ. Triiodothyronine is required for the stimulation of type II 5'-deiodinase mRNA in rat brown adipocytes. Am J Physiol Endocrinol Metab 2002; 282:E1119-27. [PMID: 11934678 DOI: 10.1152/ajpendo.00433.2001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Type II 5'-iodothyronine deiodinase (D2), produces triiodothyronine (T(3)) and is stimulated by cold exposure via norepinephrine (NE) release in brown adipose tissue. Cultured rat brown adipocytes require T(3) for the adrenergic stimulation of D2 activity. D2 mRNA expression in cultured brown adipocytes is undetectable with the use of basal conditions or NE without T(3). Full D2 expression is achieved using NE + T(3), especially after prolonged T(3) exposure. beta(3)-Adrenergic agonists mimic the NE action, whereas cAMP analogs do not. Prolonged exposure to T(3) alone increases D2 mRNA. High T(3) doses (500 nM) inhibit the adrenergic stimulation of D2 activity while increasing D2 mRNA. The effects obtained with NE + T(3) or T(3) alone are suppressed by actinomycin, but not by cycloheximide, which leads to accumulation of short D2 mRNA transcripts. Prolonged or short exposure to T(3) did not change D2 mRNA half-life, but T(3) seemed to elongate it. In conclusion, T(3) is an absolute requirement for the adrenergic stimulation of D2 mRNA in brown adipocytes. T(3) upregulates D2 mRNA, an effect that might involve stimulation of factors required for transcription or for stabilization of D2 mRNA.
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Affiliation(s)
- Raquel Martinez-deMena
- Unidad de Endocrinología Molecular, Instituto de Investigaciones Biomédicas, Centro Mixto "Alberto Sols," Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28029 Madrid, Spain
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17
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Bianco AC, Salvatore D, Gereben B, Berry MJ, Larsen PR. Biochemistry, cellular and molecular biology, and physiological roles of the iodothyronine selenodeiodinases. Endocr Rev 2002; 23:38-89. [PMID: 11844744 DOI: 10.1210/edrv.23.1.0455] [Citation(s) in RCA: 1005] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The goal of this review is to place the exciting advances that have occurred in our understanding of the molecular biology of the types 1, 2, and 3 (D1, D2, and D3, respectively) iodothyronine deiodinases into a biochemical and physiological context. We review new data regarding the mechanism of selenoprotein synthesis, the molecular and cellular biological properties of the individual deiodinases, including gene structure, mRNA and protein characteristics, tissue distribution, subcellular localization and topology, enzymatic properties, structure-activity relationships, and regulation of synthesis, inactivation, and degradation. These provide the background for a discussion of their role in thyroid physiology in humans and other vertebrates, including evidence that D2 plays a significant role in human plasma T(3) production. We discuss the pathological role of D3 overexpression causing "consumptive hypothyroidism" as well as our current understanding of the pathophysiology of iodothyronine deiodination during illness and amiodarone therapy. Finally, we review the new insights from analysis of mice with targeted disruption of the Dio2 gene and overexpression of D2 in the myocardium.
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Affiliation(s)
- Antonio C Bianco
- Thyroid Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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18
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Affiliation(s)
- Josef Köhrle
- Division of Molecular Internal Medicine, Medizinische Poliklinik, University of Wuerzburg, D-97070 Wuerzburg, Germany
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Murakami M, Araki O, Hosoi Y, Kamiya Y, Morimura T, Ogiwara T, Mizuma H, Mori M. Expression and regulation of type II iodothyronine deiodinase in human thyroid gland. Endocrinology 2001; 142:2961-7. [PMID: 11416017 DOI: 10.1210/endo.142.7.8280] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have studied the expression of type II iodothyronine deiodinase (DII) in human thyroid tumors and cultured human thyroid cells to elucidate the mechanisms involved in the regulation of DII expression in human thyroid gland. Three cases with hyperfunctioning thyroid adenoma, including a case that showed an activating mutation of G(s)alpha with a constitutive activation of cAMP production in cultured cells, and six cases with papillary thyroid carcinoma were analyzed in the present study. Free T(3) was increased, whereas free T(4) was within the normal range in all patients with hyperfunctioning thyroid adenoma. Thyroid tumor tissue and surrounding nontumor tissue were obtained at the time of surgery, and DII expression was compared between tumor tissue and nontumor tissue in each case. Northern analysis demonstrated the presence of DII messenger RNA (mRNA) approximately 7.5 kb in size in all of the tumor and nontumor tissues. DII mRNA and DII activity in hyperfunctioning thyroid adenoma were significantly increased compared with those in nontumor tissue in each case. In contrast, DII mRNA and DII activity in papillary thyroid carcinoma were decreased compared with those in nontumor tissue in each case. DII mRNA and DII activity in cultured human thyroid cells were significantly stimulated by TSH in a dose-dependent manner. The promoter activity of the human DII gene including the complete cAMP response element, transfected to cultured human thyroid cells, was stimulated by (Bu)(2)cAMP. In summary, these results suggest that DII expression in human thyroid gland is regulated at the transcriptional level through the TSH receptor-G(s)alpha-cAMP regulatory cascade, which may be related to the increase in circulating T(3) level in patients with Graves' disease and hyperfunctioning thyroid adenoma.
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Affiliation(s)
- M Murakami
- First Department of Internal Medicine, Gunma University School of Medicine, Maebashi 371-8511, Japan.
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20
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Smith M, Burke Z, Humphries A, Wells T, Klein D, Carter D, Baler R. Tissue-specific transgenic knockdown of Fos-related antigen 2 (Fra-2) expression mediated by dominant negative Fra-2. Mol Cell Biol 2001; 21:3704-13. [PMID: 11340164 PMCID: PMC87005 DOI: 10.1128/mcb.21.11.3704-3713.2001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fos-related antigen 2 (Fra-2) is a member of the Fos family of immediate-early genes, most of which are rapidly induced by second messengers. All members of this family act by binding to AP-1 sites as heterodimeric complexes with other proteins. However, each appears to have a distinct role. The role and biology of Fra-2 are less well understood than those of its relatives c-Fos, Fra-1, and FosB; moreover, Fra-2 target genes remain largely unknown, as does the basis of its selective effects on transcriptional activity. To pursue these issues, we created a transgenic rat line (NATDNF2) in which a dominant negative fra-2 (DNF2) gene is strongly expressed in the pineal gland; tissue selectivity was achieved by putting the DNF2 gene under the control of the rat arylalkylamine N-acetyltransferase (AANAT) regulatory region, which targets gene expression to a very restricted set of tissues (pineal gland >> retina). Expression of AANAT is normally turned on after the onset of darkness in the rat; as a result, pineal DNF2 expression occurs only at night. This was associated with marked suppression of the nocturnal increase in fra-2 mRNA and protein levels, indicating that DNF2 expression inhibits downstream effects of Fra-2, including the maintenance of high levels of fra-2 gene expression. Analysis of 1,190 genes in the NATDNF2 pineal gland, including the AANAT gene, identified two whose expression is strongly linked to fra-2 expression: the genes encoding type II iodothyronine deiodinase and nectadrin (CD24).
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Affiliation(s)
- M Smith
- School of Bioscience, Cardiff University, Cardiff, United Kingdom
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21
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Murakami M, Kamiya Y, Morimura T, Araki O, Imamura M, Ogiwara T, Mizuma H, Mori M. Thyrotropin receptors in brown adipose tissue: thyrotropin stimulates type II iodothyronine deiodinase and uncoupling protein-1 in brown adipocytes. Endocrinology 2001; 142:1195-201. [PMID: 11181535 DOI: 10.1210/endo.142.3.8012] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It has been demonstrated that TSH receptors are expressed not only in thyroid gland but also in extrathyroidal tissues. Brown adipose tissue of guinea pig has been reported to express TSH receptor messenger RNA (mRNA), but the physiological roles of TSH receptors in brown adipose tissue have not been understood. We studied the expression and function of TSH receptors in rat brown adipose tissue and cultured rat brown adipocytes. Northern analysis demonstrated the expression of TSH receptor mRNA in rat brown adipose tissue and cultured rat brown adipocytes. TSH receptor mRNA in rat brown adipose tissue was decreased by cold exposure of the rat, and its mRNA in cultured rat brown adipocytes was also decreased by incubation with TSH or (Bu)(2)cAMP. TSH increased the intracellular cAMP concentration in cultured rat brown adipocytes in a dose dependent manner. Type II iodothyronine deiodinase mRNA, its activity, and uncoupling protein-1 mRNA in cultured rat brown adipocytes were significantly increased by incubation with TSH in a dose-dependent manner. These results suggest the expression of functional TSH receptors in brown adipose tissue, which may be involved in regulation of the expression of type II iodothyronine deiodinase and uncoupling protein-1.
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Affiliation(s)
- M Murakami
- First Department of Internal Medicine, Gunma University School of Medicine, Maebashi 371-8511, Japan. .-u.ac.jp
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22
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Mizuma H, Murakami M, Mori M. Thyroid hormone activation in human vascular smooth muscle cells: expression of type II iodothyronine deiodinase. Circ Res 2001; 88:313-8. [PMID: 11179199 DOI: 10.1161/01.res.88.3.313] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Thyroid hormone has been reported to have significant effects on the peripheral vascular system, including relaxation of vascular smooth muscle cells and antiatherosclerotic effects. To exert its biological activity, thyroxine, which is a major secretory product of thyroid gland, needs to be converted to 3,5,3'-triiodothyronine (T(3)) by iodothyronine deiodinase. Type I iodothyronine deiodinase (DI) is widely distributed and maintains circulating T(3) level, whereas type II iodothyronine deiodinase (DII) is present in a limited number of tissues to provide local intracellular T(3). In the present study, we have identified iodothyronine deiodinase in cultured human coronary artery smooth muscle cells (hCASMCs) and human aortic smooth muscle cells (hASMCs). All of the characteristics of the deiodinating activity in hCASMCs and hASMCs were compatible with DII. Northern analysis demonstrated that DII mRNA was expressed in both hCASMCs and hASMCs, and DII mRNA levels as well as DII activities were rapidly increased by dibutyryl-cAMP or forskolin. These data demonstrate, for the first time, the expression of DII in human vascular smooth muscle cells, which is regulated by a cAMP-mediated mechanism. The present results suggest a previously unrecognized role of local T(3) production by DII in the pathophysiology of human vascular smooth muscle cells.
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MESH Headings
- Blotting, Northern
- Bucladesine/pharmacology
- Cells, Cultured
- Colforsin/pharmacology
- Gene Expression Regulation, Enzymologic/drug effects
- Humans
- Iodide Peroxidase/drug effects
- Iodide Peroxidase/genetics
- Iodide Peroxidase/metabolism
- Kinetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Thyroid Gland
- Thyroid Hormones/metabolism
- Thyroid Hormones/pharmacology
- Time Factors
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Affiliation(s)
- H Mizuma
- First Department of Internal Medicine, Gunma University School of Medicine, Maebashi, Japan
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