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Bonadonna M, Altamura S, Tybl E, Palais G, Qatato M, Polycarpou-Schwarz M, Schneider M, Kalk C, Rüdiger W, Ertl A, Anstee N, Bogeska R, Helm D, Milsom MD, Galy B. Iron regulatory protein (IRP)-mediated iron homeostasis is critical for neutrophil development and differentiation in the bone marrow. Sci Adv 2022; 8:eabq4469. [PMID: 36197975 PMCID: PMC9534496 DOI: 10.1126/sciadv.abq4469] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 08/18/2022] [Indexed: 06/01/2023]
Abstract
Iron is mostly devoted to the hemoglobinization of erythrocytes for oxygen transport. However, emerging evidence points to a broader role for the metal in hematopoiesis, including the formation of the immune system. Iron availability in mammalian cells is controlled by iron-regulatory protein 1 (IRP1) and IRP2. We report that global disruption of both IRP1 and IRP2 in adult mice impairs neutrophil development and differentiation in the bone marrow, yielding immature neutrophils with abnormally high glycolytic and autophagic activity, resulting in neutropenia. IRPs promote neutrophil differentiation in a cell intrinsic manner by securing cellular iron supply together with transcriptional control of neutropoiesis to facilitate differentiation to fully mature neutrophils. Unlike neutrophils, monocyte count was not affected by IRP and iron deficiency, suggesting a lineage-specific effect of iron on myeloid output. This study unveils the previously unrecognized importance of IRPs and iron metabolism in the formation of a major branch of the innate immune system.
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Affiliation(s)
- Michael Bonadonna
- German Cancer Research Center, “Division of Virus-Associated Carcinogenesis”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Biosciences Faculty, University of Heidelberg, 69120 Heidelberg, Germany
| | - Sandro Altamura
- University of Heidelberg, Department of Pediatric Hematology, Oncology and Immunology, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany
| | - Elisabeth Tybl
- German Cancer Research Center, “Division of Virus-Associated Carcinogenesis”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- IB-Cancer Research Foundation, Science Park 2, 66123 Saarbrücken, Germany
| | - Gael Palais
- German Cancer Research Center, “Division of Virus-Associated Carcinogenesis”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Maria Qatato
- German Cancer Research Center, “Division of Virus-Associated Carcinogenesis”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Maria Polycarpou-Schwarz
- German Cancer Research Center, “Division of Virus-Associated Carcinogenesis”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Martin Schneider
- German Cancer Research Center, Mass Spectrometry based Protein Analysis Unit, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Christina Kalk
- German Cancer Research Center, “Division of Virus-Associated Carcinogenesis”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Wibke Rüdiger
- German Cancer Research Center, “Division of Virus-Associated Carcinogenesis”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Alina Ertl
- German Cancer Research Center, “Division of Virus-Associated Carcinogenesis”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Natasha Anstee
- Heidelberg Institute for Stem Cell Technology and Experimental Medicine, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- German Cancer Research Center, “Division of Experimental Hematology”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Ruzhica Bogeska
- Heidelberg Institute for Stem Cell Technology and Experimental Medicine, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- German Cancer Research Center, “Division of Experimental Hematology”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Dominic Helm
- German Cancer Research Center, Mass Spectrometry based Protein Analysis Unit, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Michael D. Milsom
- Heidelberg Institute for Stem Cell Technology and Experimental Medicine, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- German Cancer Research Center, “Division of Experimental Hematology”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Bruno Galy
- German Cancer Research Center, “Division of Virus-Associated Carcinogenesis”, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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Qatato M, Venugopalan V, Al-Hashimi A, Rehders M, Valentine AD, Hein Z, Dallto U, Springer S, Brix K. Trace Amine-Associated Receptor 1 Trafficking to Cilia of Thyroid Epithelial Cells. Cells 2021; 10:cells10061518. [PMID: 34208608 PMCID: PMC8234161 DOI: 10.3390/cells10061518] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 12/14/2022] Open
Abstract
Trace amine-associated receptor 1 (rodent Taar1/human TAAR1) is a G protein-coupled receptor that is mainly recognized for its functions in neuromodulation. Previous in vitro studies suggested that Taar1 may signal from intracellular compartments. However, we have shown Taar1 to localize apically and on ciliary extensions in rodent thyrocytes, suggesting that at least in the thyroid, Taar1 may signal from the cilia at the apical plasma membrane domain of thyrocytes in situ, where it is exposed to the content of the follicle lumen containing putative Taar1 ligands. This study was designed to explore mouse Taar1 (mTaar1) trafficking, heterologously expressed in human and rat thyroid cell lines in order to establish an in vitro system in which Taar1 signaling from the cell surface can be studied in future. The results showed that chimeric mTaar1-EGFP traffics to the apical cell surface and localizes particularly to spherical structures of polarized thyroid cells, procilia, and primary cilia upon serum-starvation. Moreover, mTaar1-EGFP appears to form high molecular mass forms, possibly homodimers and tetramers, in stably expressing human thyroid cell lines. However, only monomeric mTaar1-EGFP was cell surface biotinylated in polarized human thyrocytes. In polarized rat thyrocytes, mTaar1-EGFP is retained in the endoplasmic reticulum, while cilia were reached by mTaar1-EGFP transiently co-expressed in combination with an HA-tagged construct of the related mTaar5. We conclude that Taar1 trafficking to cilia depends on their integrity. The results further suggest that an in vitro cell model was established that recapitulates Taar1 trafficking in thyrocytes in situ, in principle, and will enable studying Taar1 signaling in future, thus extending our general understanding of its potential significance for thyroid autoregulation.
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Venugopalan V, Al-Hashimi A, Weber J, Rehders M, Qatato M, Wirth EK, Schweizer U, Heuer H, Verrey F, Brix K. The Amino Acid Transporter Mct10/Tat1 Is Important to Maintain the TSH Receptor at Its Canonical Basolateral Localization and Assures Regular Turnover of Thyroid Follicle Cells in Male Mice. Int J Mol Sci 2021; 22:5776. [PMID: 34071318 PMCID: PMC8198332 DOI: 10.3390/ijms22115776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/20/2021] [Accepted: 05/26/2021] [Indexed: 12/03/2022] Open
Abstract
Cathepsin K-mediated thyroglobulin proteolysis contributes to thyroid hormone (TH) liberation, while TH transporters like Mct8 and Mct10 ensure TH release from thyroid follicles into the blood circulation. Thus, thyroid stimulating hormone (TSH) released upon TH demand binds to TSH receptors of thyrocytes, where it triggers Gαq-mediated short-term effects like cathepsin-mediated thyroglobulin utilization, and Gαs-mediated long-term signaling responses like thyroglobulin biosynthesis and thyrocyte proliferation. As reported recently, mice lacking Mct8 and Mct10 on a cathepsin K-deficient background exhibit excessive thyroglobulin proteolysis hinting towards altered TSH receptor signaling. Indeed, a combination of canonical basolateral and non-canonical vesicular TSH receptor localization was observed in Ctsk-/-/Mct8-/y/Mct10-/- mice, which implies prolonged Gαs-mediated signaling since endo-lysosomal down-regulation of the TSH receptor was not detected. Inspection of single knockout genotypes revealed that the TSH receptor localizes basolaterally in Ctsk-/- and Mct8-/y mice, whereas its localization is restricted to vesicles in Mct10-/- thyrocytes. The additional lack of cathepsin K reverses this effect, because Ctsk-/-/Mct10-/- mice display TSH receptors basolaterally, thereby indicating that cathepsin K and Mct10 contribute to TSH receptor homeostasis by maintaining its canonical localization in thyrocytes. Moreover, Mct10-/- mice displayed reduced numbers of dead thyrocytes, while their thyroid gland morphology was comparable to wild-type controls. In contrast, Mct8-/y, Mct8-/y/Mct10-/-, and Ctsk-/-/Mct8-/y/Mct10-/- mice showed enlarged thyroid follicles and increased cell death, indicating that Mct8 deficiency results in altered thyroid morphology. We conclude that vesicular TSH receptor localization does not result in different thyroid tissue architecture; however, Mct10 deficiency possibly modulates TSH receptor signaling for regulating thyrocyte survival.
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Affiliation(s)
- Vaishnavi Venugopalan
- Department of Life Sciences and Chemistry, Focus Area HEALTH, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany; (V.V.); (A.A.-H.); (J.W.); (M.R.); (M.Q.)
| | - Alaa Al-Hashimi
- Department of Life Sciences and Chemistry, Focus Area HEALTH, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany; (V.V.); (A.A.-H.); (J.W.); (M.R.); (M.Q.)
| | - Jonas Weber
- Department of Life Sciences and Chemistry, Focus Area HEALTH, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany; (V.V.); (A.A.-H.); (J.W.); (M.R.); (M.Q.)
| | - Maren Rehders
- Department of Life Sciences and Chemistry, Focus Area HEALTH, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany; (V.V.); (A.A.-H.); (J.W.); (M.R.); (M.Q.)
| | - Maria Qatato
- Department of Life Sciences and Chemistry, Focus Area HEALTH, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany; (V.V.); (A.A.-H.); (J.W.); (M.R.); (M.Q.)
| | - Eva K. Wirth
- Berlin Institute of Health, Department of Endocrinology and Metabolism, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Hessische Str. 3-4, D-10115 Berlin, Germany;
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Nußallee 11, D-53115 Bonn, Germany;
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University of Duisburg-Essen, Universitätsklinikum Essen, Hufelandstr. 55, D-45147 Essen, Germany;
| | - François Verrey
- Physiologisches Institut, Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland;
| | - Klaudia Brix
- Department of Life Sciences and Chemistry, Focus Area HEALTH, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany; (V.V.); (A.A.-H.); (J.W.); (M.R.); (M.Q.)
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Brix K, Szumska J, Weber J, Qatato M, Venugopalan V, Al-Hashimi A, Rehders M. Auto-Regulation of the Thyroid Gland Beyond Classical Pathways. Exp Clin Endocrinol Diabetes 2020; 128:437-445. [PMID: 32074633 DOI: 10.1055/a-1080-2969] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This mini-review asks how self-regulation of the thyroid gland is realized at the cellular and molecular levels by canonical and non-canonical means. Canonical pathways of thyroid regulation comprise thyroid stimulating hormone-triggered receptor signaling. As part of non-canonical regulation, we hypothesized an interplay between protease-mediated thyroglobulin processing and thyroid hormone release into the circulation by means of thyroid hormone transporters like Mct8. We proposed a sensing mechanism by different thyroid hormone transporters, present in specific subcellular locations of thyroid epithelial cells, selectively monitoring individual steps of thyroglobulin processing, and thus, the cellular thyroid hormone status. Indeed, we found that proteases and thyroid hormone transporters are functionally inter-connected, however, in a counter-intuitive manner fostering self-thyrotoxicity in particular in Mct8- and/or Mct10-deficient mice. Furthermore, the possible role of the G protein-coupled receptor Taar1 is discussed, because we detected Taar1 at cilia of the apical plasma membrane of thyrocytes in vitro and in situ. Eventually, through pheno-typing Taar1-deficient mice, we identified a co-regulatory role of Taar1 and the thyroid stimulating hormone receptors. Recently, we showed that inhibition of thyroglobulin-processing enzymes results in disappearance of cilia from the apical pole of thyrocytes, while Taar1 is re-located to the endoplasmic reticulum. This pathway features a connection between thyrotropin-stimulated secretion of proteases into the thyroid follicle lumen and substrate-mediated self-assisted control of initially peri-cellular thyroglobulin processing, before its reinternalization by endocytosis, followed by extensive endo-lysosomal liberation of thyroid hormones, which are then released from thyroid follicles by means of thyroid hormone transporters.
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Affiliation(s)
- Klaudia Brix
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Joanna Szumska
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany.,Present address of JS is Department of Internal Medicine III, Cardiology, Angiology and Respiratory Medicine, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Jonas Weber
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Maria Qatato
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Vaishnavi Venugopalan
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Alaa Al-Hashimi
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Maren Rehders
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
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Qatato M, Szumska J, Skripnik V, Rijntjes E, Köhrle J, Brix K. Canonical TSH Regulation of Cathepsin-Mediated Thyroglobulin Processing in the Thyroid Gland of Male Mice Requires Taar1 Expression. Front Pharmacol 2018; 9:221. [PMID: 29615904 PMCID: PMC5870035 DOI: 10.3389/fphar.2018.00221] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 02/27/2018] [Indexed: 12/26/2022] Open
Abstract
Trace amine-associated receptor 1 (Taar1) has been suggested as putative receptor of thyronamines. These are aminergic messengers with potential metabolic and neurological effects countering their contingent precursors, the thyroid hormones (THs). Recently, we found Taar1 to be localized at the primary cilia of rodent thyroid epithelial cells in vitro and in situ. Thus, Taar1 is present in a location of thyroid follicles where it might be involved in regulation of cathepsin-mediated proteolytic processing of thyroglobulin, and consequently TH synthesis. In this study, taar1 knock-out male mice (taar1-/-) were used to determine whether Taar1 function would entail differential alterations in thyroid states of young and adult animals. Analyses of blood serum revealed unaltered T4 and T3 concentrations and unaltered T3-over-T4 ratios upon Taar1 deficiency accompanied, however, by elevated TSH concentrations. Interestingly, TSH receptors, typically localized at the basolateral plasma membrane domain of wild type controls, were located at vesicular membranes in thyrocytes of taar1-/- mice. In addition, determination of epithelial extensions in taar1-/- thyroids showed prismatic cells, which might indicate activation states higher than in the wild type. While gross degradation of thyroglobulin was comparable to controls, deregulated thyroglobulin turnover in taar1-/- mice was indicated by luminal accumulation of covalently cross-linked thyroglobulin storage forms. These findings were in line with decreased proteolytic activities of thyroglobulin-solubilizing and -processing proteases, due to upregulated cystatins acting as their endogenous inhibitors in situ. In conclusion, Taar1-deficient mice are hyperthyrotropinemic in the absence of respective signs of primary hypothyroidism such as changes in body weight or TH concentrations in blood serum. Thyrocytes of taar1-/- mice are characterized by non-canonical TSH receptor localization in intracellular compartments, which is accompanied by altered thyroglobulin turnover due to a disbalanced proteolytic network. These finding are of significance considering the rising popularity of using TAAR1 agonists or antagonists as neuromodulating pharmacological drugs. Our study highlights the importance of further evaluating potential off-target effects regarding TSH receptor mislocalization and the thyroglobulin processing machinery, which may not only affect the TH-generating thyroid gland, but may emanate to other TH target organs like the CNS dependent on their proper supply.
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Affiliation(s)
- Maria Qatato
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Joanna Szumska
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Vladislav Skripnik
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Eddy Rijntjes
- Institut für Experimentelle Endokrinologie, Charité - Universitätsmedizin Berlin, Freie Universität Berlin-Humboldt-Universität zu Berlin-Berlin Institute of Health, Berlin, Germany
| | - Josef Köhrle
- Institut für Experimentelle Endokrinologie, Charité - Universitätsmedizin Berlin, Freie Universität Berlin-Humboldt-Universität zu Berlin-Berlin Institute of Health, Berlin, Germany
| | - Klaudia Brix
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
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Weber J, McInnes J, Kizilirmak C, Rehders M, Qatato M, Wirth EK, Schweizer U, Verrey F, Heuer H, Brix K. Interdependence of thyroglobulin processing and thyroid hormone export in the mouse thyroid gland. Eur J Cell Biol 2017; 96:440-456. [PMID: 28274595 DOI: 10.1016/j.ejcb.2017.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/08/2017] [Accepted: 02/09/2017] [Indexed: 02/08/2023] Open
Abstract
Thyroid hormone (TH) target cells need to adopt mechanisms to maintain sufficient levels of TH to ensure regular functions. This includes thyroid epithelial cells, which generate TH in addition to being TH-responsive. However, the cellular and molecular pathways underlying thyroid auto-regulation are insufficiently understood. In order to investigate whether thyroglobulin processing and TH export are sensed by thyrocytes, we inactivated thyroglobulin-processing cathepsins and TH-exporting monocarboxylate transporters (Mct) in the mouse. The states of thyroglobulin storage and its protease-mediated processing and degradation were related to the levels of TH transporter molecules by immunoblotting and immunofluorescence microscopy. Thyroid epithelial cells of cathepsin-deficient mice showed increased Mct8 protein levels at the basolateral plasma membrane domains when compared to wild type controls. While the protein amounts of the thyroglobulin-degrading cathepsin D remained largely unaffected by Mct8 or Mct10 single-deficiencies, a significant increase in the amounts of the thyroglobulin-processing cathepsins B and L was detectable in particular in Mct8/Mct10 double deficiency. In addition, it was observed that larger endo-lysosomes containing cathepsins B, D, and L were typical for Mct8- and/or Mct10-deficient mouse thyroid epithelial cells. These data support the notion of a crosstalk between TH transporters and thyroglobulin-processing proteases in thyroid epithelial cells. We conclude that a defect in exporting thyroxine from thyroid follicles feeds back positively on its cathepsin-mediated proteolytic liberation from the precursor thyroglobulin, thereby adding to the development of auto-thyrotoxic states in Mct8 and/or Mct10 deficiencies. The data suggest TH sensing molecules within thyrocytes that contribute to thyroid auto-regulation.
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Affiliation(s)
- Jonas Weber
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Joseph McInnes
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Cise Kizilirmak
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Maren Rehders
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Maria Qatato
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Eva K Wirth
- Charité-Universitätsmedizin Berlin, Institut für Experimentelle Endokrinologie, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Ulrich Schweizer
- Universität Bonn, Institut für Biochemie und Molekularbiologie, Nußallee 11, D-53115 Bonn, Germany
| | - Francois Verrey
- Universität Zürich, Physiologisches Institut, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Heike Heuer
- IUF - Leibniz Institut für umweltmedizinische Forschung, Auf'm Hennekamp 50, D-40225 Düsseldorf, Germany
| | - Klaudia Brix
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany.
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Szumska J, Qatato M, Rehders M, Führer D, Biebermann H, Grandy DK, Köhrle J, Brix K. Trace Amine-Associated Receptor 1 Localization at the Apical Plasma Membrane Domain of Fisher Rat Thyroid Epithelial Cells Is Confined to Cilia. Eur Thyroid J 2015; 4:30-41. [PMID: 26601071 PMCID: PMC4640295 DOI: 10.1159/000434717] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 06/02/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The trace amine-associated receptor 1 (Taar1) is one member of the Taar family of G-protein-coupled receptors (GPCR) accepting various biogenic amines as ligands. It has been proposed that Taar1 mediates rapid, membrane-initiated effects of thyronamines, the endogenous decarboxylated and deiodinated relatives of the classical thyroid hormones T4 and T3. OBJECTIVES Although the physiological actions of thyronamines in general and 3-iodothyronamine (T1AM) in particular are incompletely understood, studies published to date suggest that synthetic T1AM-activated Taar1 signaling antagonizes thyromimetic effects exerted by T3. However, the location of Taar1 is currently unknown. METHODS To fill this gap in our knowledge we employed immunofluorescence microscopy and a polyclonal antibody to detect Taar1 protein expression in thyroid tissue from Fisher rats, wild-type and taar1-deficient mice, and in the polarized FRT cells. RESULTS With this approach we found that Taar1 is expressed in the membranes of subcellular compartments of the secretory pathway and on the apical plasma membrane of FRT cells. Three-dimensional analyses further revealed Taar1 immunoreactivity in cilial extensions of postconfluent FRT cell cultures that had formed follicle-like structures. CONCLUSIONS The results suggest Taar1 transport along the secretory pathway and its accumulation in the primary cilium of thyrocytes. These findings are of significance considering the increasing interest in the role of cilia in harboring functional GPCR. We hypothesize that thyronamines can reach and activate Taar1 in thyroid follicular epithelia by acting from within the thyroid follicle lumen, their potential site of synthesis, as part of a nonclassical mechanism of thyroid autoregulation.
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Affiliation(s)
- Joanna Szumska
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Maria Qatato
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Maren Rehders
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Dagmar Führer
- Department of Endocrinology and Metabolism and Division of Laboratory Research, University of Duisburg-Essen, Essen, Germany
| | - Heike Biebermann
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - David K. Grandy
- Department of Physiology and Pharmacology, School of Medicine and the Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oreg., USA
| | - Josef Köhrle
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Klaudia Brix
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
- *Dr. Klaudia Brix, Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, DE-28759 Bremen (Germany), E-Mail
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Qatato M, Venugopalan V, Amoah A, Szumska J, Dinter J, Biebermann H, Brix K. Visualising trafficking of trace amine-associated receptors (TAAR) in polarised thyroid epithelial cells. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Szumska J, Qatato M, Venugopalan V, Rehders M, Völker U, Homuth G, Biebermann H, Brix K. Expression and localization of trace amine-associated receptors in thyroid epithelial cells treated with cathepsin B and K inhibitors. Exp Clin Endocrinol Diabetes 2014. [DOI: 10.1055/s-0034-1372164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Qatato M, Amoah A, Szumska J, Venugopalan V, Babusyte A, Dinter J, Krautwurst D, Biebermann H, Brix K. TAAR expression in thyroid epithelial cell lines as to establish an in vitro-model for signalling analysis. Exp Clin Endocrinol Diabetes 2014. [DOI: 10.1055/s-0034-1372100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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