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Feng F, Han H, Wu S, Wang H. Crosstalk Between Abnormal TSHR Signaling Activation and PTEN/PI3K in the Dedifferentiation of Thyroid Cancer Cells. Front Oncol 2021; 11:718578. [PMID: 34650915 PMCID: PMC8506026 DOI: 10.3389/fonc.2021.718578] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/08/2021] [Indexed: 11/29/2022] Open
Abstract
Iodide uptake and the metabolism of thyroid cells are regulated by thyrotropin (TSH)-TSH receptor (TSHR) signaling. Thus, it is necessary to elevate serum TSH levels by T4 withdraw or rTSH administration to facilitate radioiodide (131I) therapy for differentiated thyroid cancer (DTC). However, non-iodide-avid metastases of DTC which is dedifferentiated do not respond to stimulation by high levels of TSH, suggesting abnormal TSH-TSHR signal transduction in cancer cells. In addition, PI3K/AKT/mTOR signaling activation has been shown to be associated with the dedifferentiated phenotype of thyroid cancer, but the mechanism remains elusive. Therefore, in this study, we aimed to explore the role of abnormal TSH-TSHR signaling activation in regulating iodide uptake and cell mobility in thyroid cancer and its relationship with PI3K/AKT/mTOR signaling. We found that in thyroid cancer cells, TSH binds TSHR coupled to the Gα12/13 protein and then activates RhoA through interacting with leukemia associated RhoA guanine exchange factor (LARG). This results in a promigration tumorigenic phenotype independent of canonical TSHR-GαS signaling that regulates the expression of molecules involved in iodine uptake and metabolism. We observed that signaling pathways downstream of Gα12/13 signaling were increased, while that of Gαs signaling was decreased in thyroid cancer cells undergoing dedifferentiation compared to control cells following stimulation with different levels of TSH. PI3K/AKT/mTOR signaling activation enhanced Gα12/13 signaling through increasing LARG levels but also inhibited the expression of molecules downstream of Gαs signaling, including thyroid-specific molecules, and iodide uptake. In summary, our results demonstrate the noncanonical activation of TSH-TSHR signaling and its role in increasing the cell mobility and dedifferentiation of thyroid cancer through crosstalk with PI3K/AKT/mTOR signaling.
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Affiliation(s)
- Fang Feng
- Department of Nuclear Medicine, Xinhua Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Huiqin Han
- Shanghai Mental Health Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Shuqi Wu
- Department of Nuclear Medicine, Xinhua Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Hui Wang
- Department of Nuclear Medicine, Xinhua Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
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Asghar MY, Lassila T, Törnquist K. Calcium Signaling in the Thyroid: Friend and Foe. Cancers (Basel) 2021; 13:cancers13091994. [PMID: 33919125 PMCID: PMC8122656 DOI: 10.3390/cancers13091994] [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: 03/11/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary All cells in our body are activated by several different signals. The calcium ion is one of the most versatile signaling molecules, and regulates a multitude of different events in the cells. These range from activation of muscle contraction, to the regulation of cell movement, just to name a few. In normal thyroid cells, calcium signaling is of importance for the normal physiology of the cells. In thyroid pathologies, e.g., thyroid cancer, calcium is important for the regulation of proliferation and invasion, and may also activate gene transcription programs important for cancer cell survival. In this Commentary, we summarize what is known regarding calcium in the normal thyroid, and highlight the importance of calcium signaling in thyroid pathologies. Abstract Calcium signaling participates in a vast number of cellular processes, ranging from the regulation of muscle contraction, cell proliferation, and mitochondrial function, to the regulation of the membrane potential in cells. The actions of calcium signaling are, thus, of great physiological significance for the normal functioning of our cells. However, many of the processes that are regulated by calcium, including cell movement and proliferation, are important in the progression of cancer. In the normal thyroid, calcium signaling plays an important role, and evidence is also being gathered showing that calcium signaling participates in the progression of thyroid cancer. This review will summarize what we know in regard to calcium signaling in the normal thyroid as, well as in thyroid cancer.
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Affiliation(s)
- Muhammad Yasir Asghar
- Minerva Foundation Institute for Medical Research, Biomedicum Helsinki 2U, Tukholmankatu 8, 00290 Helsinki, Finland; (M.Y.A.); (T.L.)
| | - Taru Lassila
- Minerva Foundation Institute for Medical Research, Biomedicum Helsinki 2U, Tukholmankatu 8, 00290 Helsinki, Finland; (M.Y.A.); (T.L.)
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6, 00250 Turku, Finland
| | - Kid Törnquist
- Minerva Foundation Institute for Medical Research, Biomedicum Helsinki 2U, Tukholmankatu 8, 00290 Helsinki, Finland; (M.Y.A.); (T.L.)
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6, 00250 Turku, Finland
- Correspondence:
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Kyrilli A, Gacquer D, Detours V, Lefort A, Libert F, Twyffels L, Van Den Eeckhaute L, Strickaert A, Maenhaut C, De Deken X, Dumont JE, Miot F, Corvilain B. Dissecting the Role of Thyrotropin in the DNA Damage Response in Human Thyrocytes after 131I, γ Radiation and H2O2. J Clin Endocrinol Metab 2020; 105:5614560. [PMID: 31701151 DOI: 10.1210/clinem/dgz185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/15/2019] [Accepted: 11/05/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND The early molecular events in human thyrocytes after 131I exposure have not yet been unravelled. Therefore, we investigated the role of TSH in the 131I-induced DNA damage response and gene expression in primary cultured human thyrocytes. METHODS Following exposure of thyrocytes, in the presence or absence of TSH, to 131I (β radiation), γ radiation (3 Gy), and hydrogen peroxide (H2O2), we assessed DNA damage, proliferation, and cell-cycle status. We conducted RNA sequencing to profile gene expression after each type of exposure and evaluated the influence of TSH on each transcriptomic response. RESULTS Overall, the thyrocyte responses following exposure to β or γ radiation and to H2O2 were similar. However, TSH increased 131I-induced DNA damage, an effect partially diminished after iodide uptake inhibition. Specifically, TSH increased the number of DNA double-strand breaks in nonexposed thyrocytes and thus predisposed them to greater damage following 131I exposure. This effect most likely occurred via Gα q cascade and a rise in intracellular reactive oxygen species (ROS) levels. β and γ radiation prolonged thyroid cell-cycle arrest to a similar extent without sign of apoptosis. The gene expression profiles of thyrocytes exposed to β/γ radiation or H2O2 were overlapping. Modulations in genes involved in inflammatory response, apoptosis, and proliferation were observed. TSH increased the number and intensity of modulation of differentially expressed genes after 131I exposure. CONCLUSIONS TSH specifically increased 131I-induced DNA damage probably via a rise in ROS levels and produced a more prominent transcriptomic response after exposure to 131I.
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Affiliation(s)
- Aglaia Kyrilli
- Division of Endocrinology, Erasme Hospital, Université Libre de Bruxelles (ULB), Brussels, Belgium
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - David Gacquer
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Vincent Detours
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Anne Lefort
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Frédéric Libert
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Laure Twyffels
- Center for Microscopy and Molecular Imaging (CMMI), Gosselies Biopark, ULB, Gosselies, Belgium
| | - Laura Van Den Eeckhaute
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Aurélie Strickaert
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Carine Maenhaut
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Xavier De Deken
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Jacques Emile Dumont
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Françoise Miot
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
| | - Bernard Corvilain
- Division of Endocrinology, Erasme Hospital, Université Libre de Bruxelles (ULB), Brussels, Belgium
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire (IRIBHM), School of Medicine, ULB, Brussels, Belgium
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Liver-specific deletion of TSHR inhibits hepatic lipid accumulation in mice. Biochem Biophys Res Commun 2018; 497:39-45. [PMID: 29421660 DOI: 10.1016/j.bbrc.2018.01.187] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 01/30/2018] [Indexed: 12/27/2022]
Abstract
The effect of thyroid-stimulating hormone receptor (TSHR) on hepatic lipid accumulation in vivo is not fully understood. Further, while TSHR in the thyroid has been studied extensively, whether and how the absence of TSHR in the liver affects systemic energy metabolism has not yet been reported. To examine these effects, we generated hepatic TSHR conditional knockout (LT-KO) mice using Cre/LoxP recombination technology. The liver-specific TSHR-knockout (LT-KO) mice exhibited not only lower hepatic triglyceride and cholesterol contents due to modified synthesis and catabolism of lipids in the liver, but also decreased serum lipids, especially serum LDL-C levels. Abnormalities of TSHR in the thyroid affect whole-body energy balance; however, measurements taken in metabolic chambers showed that the hepatic TSHR conditional deletion had no impact on systemic energy metabolism. Unlike its critical role in maintaining the normal growth and function of the thyroid gland, our results demonstrated that hepatic TSHR is involved in liver lipid metabolism and has little effect on energy metabolism.
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Khajavi N, Mergler S, Biebermann H. 3-Iodothyronamine, a Novel Endogenous Modulator of Transient Receptor Potential Melastatin 8? Front Endocrinol (Lausanne) 2017; 8:198. [PMID: 28861042 PMCID: PMC5561014 DOI: 10.3389/fendo.2017.00198] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 07/28/2017] [Indexed: 11/22/2022] Open
Abstract
The decarboxylated and deiodinated thyroid hormone (TH) derivative, 3-iodothyronamine (3-T1AM), is suggested to be involved in energy metabolism and thermoregulation. G protein-coupled receptors (GPCRs) are known as the main targets for 3-T1AM; however, transient receptor potential channels (TRPs) were also recently identified as new targets of 3-T1AM. This article reviews the current knowledge of a putative novel role of 3-T1AM in the modulation of TRPs. Specifically, the TRP melastatin 8 (TRPM8) was identified as a target of 3-T1AM in different cell types including neoplastic cells, whereby 3-T1AM significantly increased cytosolic Ca2+ through TRPM8 activation. Similarly, the β-adrenergic receptor is involved in 3-T1AM-induced Ca2+ influx. Therefore, it has been suggested that 3-T1AM-induced Ca2+ mobilization might be due to β-adrenergic receptor/TRPM8 channel interaction, which adds to the complexity of GPCR regulation by TRPs. It has been revealed that TRPM8 activation leads to a decline in TRPV1 activity, which may be of therapeutic benefit in clinical circumstances such as treatment of TRPV1-mediated inflammatory hyperalgesia, colitis, and dry eye syndrome. This review also summarizes the inverse association between changes in TRPM8 and TRPV1 activity after 3-T1AM stimulation. This finding prompted further detailed investigations of the interplay between 3-T1AM and the GPCR/TRPM8 axis and indicated the probability of additional GPCR/TRP constellations that are modulated by this TH derivative.
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Affiliation(s)
- Noushafarin Khajavi
- Institute for Experimental Pediatric Endocrinology, Charité University of Medicine Berlin, Berlin, Germany
- *Correspondence: Noushafarin Khajavi,
| | - Stefan Mergler
- Department of Ophthalmology, Charité University of Medicine Berlin, Berlin, Germany
| | - Heike Biebermann
- Institute for Experimental Pediatric Endocrinology, Charité University of Medicine Berlin, Berlin, Germany
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Morgan SJ, Neumann S, Marcus-Samuels B, Gershengorn MC. Thyrotropin and Insulin-Like Growth Factor 1 Receptor Crosstalk Upregulates Sodium-Iodide Symporter Expression in Primary Cultures of Human Thyrocytes. Thyroid 2016; 26:1794-1803. [PMID: 27638195 PMCID: PMC5175432 DOI: 10.1089/thy.2016.0323] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Major regulation of thyroid gland function is mediated by thyrotropin (TSH) activating the TSH receptor (TSHR) and inducing upregulation of genes involved in thyroid hormone synthesis. Evidence suggests that the insulin-like growth factor 1 (IGF-1) receptor (IGF-1R) may play a role in regulating TSHR functional effects. This study examined the potential role of TSHR/IGF-1R crosstalk in primary cultures of human thyrocytes. RESULTS TSH/IGF-1 co-treatment elicited additive effects on thyroglobulin (TG), thyroperoxidase (TPO), and deiodinase type 2 (DIO2) mRNA levels but synergistic effects on sodium-iodide symporter (NIS) mRNA. Similar cooperativity was seen on the level of TG protein secretion (additive) and NIS protein expression (synergistic). The IGF-1R tyrosine kinase inhibitor linsitinib inhibited TSH-stimulated upregulation of NIS but not TG, indicating that NIS regulation is in part IGF-1R dependent and occurs via receptor crosstalk. Cooperativity was not seen at the level of cAMP/protein kinase A (PKA) signaling, IGF-1R phosphorylation, or Akt activation. However, TSH and IGF-1 synergistically activated ERK1/2. Pharmacological inhibition of ERK1/2 by the MEK1/2 inhibitor U0126 and of Akt by MK-2206 virtually abolished NIS stimulation by TSH and the synergistic effect of IGF-1. CONCLUSION As linsitinib inhibited upregulation of NIS stimulated by TSH alone, it is concluded that crosstalk between TSHR and IGF-1R, without agonist activation of IGF-1R, plays a role in NIS regulation in human thyrocytes via a mechanism involving ERK1/2 and/or Akt. Fully understanding the nature of this crosstalk has clinical implications for the treatment of thyroid diseases, including thyroid cancer.
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Affiliation(s)
- Sarah J Morgan
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland
| | - Susanne Neumann
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland
| | - Bernice Marcus-Samuels
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland
| | - Marvin C Gershengorn
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland
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Wronska D. Thyroid gland in vitro activity and reactivity to TRH in newborn lambs. Res Vet Sci 2015; 102:67-71. [PMID: 26412522 DOI: 10.1016/j.rvsc.2015.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 07/02/2015] [Accepted: 07/09/2015] [Indexed: 11/17/2022]
Abstract
The aim of the study was to determine the thyroid gland tissue concentration and activity on T4 and T3 in vitro release to the medium without (control) or with TRH (10 μg/ml) for 90 min of incubation in lambs just after birth and after the first 6h of postnatal life. The results obtained show that T4 concentration in the blood plasma in newborn lambs as well after 6h of life is higher than in thyroid gland tissue. In the case of T3 the concentration in blood plasma of lambs just after birth is lower than after 6h of postnatal life. Inversely, the higher level of that hormone concentration in blood plasma just after birth is higher than in the thyroid gland tissue. The results clearly indicate the inhibitory TRH effect on in vitro T4 especially, and in lesser degree T3 release from the thyroid gland tissue of lambs just after birth. Stimulation of the TRH thyroid gland tissue from lambs after 6h of life caused an increase in T4 release, especially after 60 min of the experiment. Similarly, a significant increase of T3 release was found only after 60 min of incubation. The transient promoting TRH effect on the amount of iodothyronine release from the thyroid gland in older lambs is probably connected with this gland's function not occurring before the designated time of postnatal adaptation. The described in vitro experiment visibly shows that changing thyroid gland activity in newborn lambs is not only conditioned by the entire HPT activity, but by the immanent thyroid gland attributes as well.
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Affiliation(s)
- D Wronska
- Department of Physiology and Endocrinology, Faculty of Animal Sciences, Hugo Kollataj Agricultural University in Cracow, Poland.
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Abstract
Adenosine-5'-triphosphate is released by neuroendocrine, endocrine, and other cell types and acts as an extracellular agonist for ligand-gated P2X cationic channels and G protein-coupled P2Y receptors in numerous organs and tissues, including the endocrine system. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5'-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors, also expressed in the endocrine system. This article provides a review of purinergic signaling pathways in the hypothalamic magnocellular neurosecretory cells and neurohypophysis, hypothalamic parvocellular neuroendocrine system, adenohypophysis, and effector glands organized in five axes: hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-growth hormone, and hypothalamic-pituitary-prolactin. We attempted to summarize current knowledge of purinergic receptor subtypes expressed in the endocrine system, including their roles in intracellular signaling, hormone secretion, and other cell functions. We also briefly review the release mechanism for adenosine-5'-triphosphate by neuroendocrine, endocrine and surrounding cells, the enzymes involved in adenosine-5'-triphosphate hydrolysis to adenosine-5'-diphosphate and adenosine, and the relevance of this pathway for sequential activation of receptors and termination of signaling.
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Canonical transient receptor potential channel 2 (TRPC2): old name-new games. Importance in regulating of rat thyroid cell physiology. Pflugers Arch 2014; 466:2025-34. [PMID: 24722829 DOI: 10.1007/s00424-014-1509-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 03/25/2014] [Accepted: 03/26/2014] [Indexed: 12/14/2022]
Abstract
In addition to the TSH-cyclic AMP signalling pathway, calcium signalling is of crucial importance in thyroid cells. Although the importance of calcium signalling has been thoroughly investigated for several decades, the nature of the calcium channels involved in signalling is unknown. In a recent series of investigations using the well-studied rat thyroid FRTL-5 cell line, we showed that these cells exclusively express the transient receptor potential canonical 2 (TRPC2) channel. Our results suggested that the TRPC2 channel is of significant importance in regulating thyroid cell function. These investigations were the first to show that thyroid cells express a member of the TRPC family of ion channels. In this review, we will describe the importance of the TRPC2 channel in regulating TSH receptor expression, thyroglobulin maturation, intracellular calcium and iodide homeostasis and that the channel also regulates thyroid cell proliferation.
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Burnstock G. Purinergic signalling in endocrine organs. Purinergic Signal 2014; 10:189-231. [PMID: 24265070 PMCID: PMC3944044 DOI: 10.1007/s11302-013-9396-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/08/2023] Open
Abstract
There is widespread involvement of purinergic signalling in endocrine biology. Pituitary cells express P1, P2X and P2Y receptor subtypes to mediate hormone release. Adenosine 5'-triphosphate (ATP) regulates insulin release in the pancreas and is involved in the secretion of thyroid hormones. ATP plays a major role in the synthesis, storage and release of catecholamines from the adrenal gland. In the ovary purinoceptors mediate gonadotrophin-induced progesterone secretion, while in the testes, both Sertoli and Leydig cells express purinoceptors that mediate secretion of oestradiol and testosterone, respectively. ATP released as a cotransmitter with noradrenaline is involved in activities of the pineal gland and in the neuroendocrine control of the thymus. In the hypothalamus, ATP and adenosine stimulate or modulate the release of luteinising hormone-releasing hormone, as well as arginine-vasopressin and oxytocin. Functionally active P2X and P2Y receptors have been identified on human placental syncytiotrophoblast cells and on neuroendocrine cells in the lung, skin, prostate and intestine. Adipocytes have been recognised recently to have endocrine function involving purinoceptors.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Kleinau G, Biebermann H. Constitutive activities in the thyrotropin receptor: regulation and significance. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 70:81-119. [PMID: 24931193 DOI: 10.1016/b978-0-12-417197-8.00003-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The thyroid-stimulating hormone receptor (TSHR, or thyrotropin receptor) is a family A G protein-coupled receptor. It not only binds thyroid-stimulating hormone (TSH, or thyrotropin) but also interacts with autoantibodies under pathological conditions. The TSHR and TSH are essential for thyroid growth and function and thus for all thyroid hormone-associated physiological superordinated processes, including metabolism and development of the central nervous system. In vitro studies have found that the TSHR permanently stimulates ligand-independent (constitutive) activation of Gs, which ultimately leads to intracellular cAMP accumulation. Furthermore, a vast variety of constitutively activating mutations of TSHR-at more than 50 different amino acid positions-have been reported to enhance basal signaling. These lead in vivo to a "gain-of-function" phenotype of nonautoimmune hyperthyroidism or toxic adenomas. Moreover, many naturally occurring inactivating mutations are known to cause a "loss-of-function" phenotype, resulting in resistance to thyroid hormone or hyperthyrotropinemia. Several of these mutations are also characterized by impaired basal signaling, and these are designated here as "constitutively inactivating mutations" (CIMs). More than 30 amino acid positions with CIMs have been identified so far. Moreover, the permanent TSHR signaling capacity can also be blocked by inverse agonistic antibodies or small drug-like molecules, which both have a potential for clinical usage. In this chapter, information on constitutive activity in the TSHR is described, including up- and downregulation, linked protein conformations, physiological and pathophysiological conditions, and related intracellular signaling.
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Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Ca(2+)-binding protein expression in primary human thyrocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2703-2713. [PMID: 23886630 DOI: 10.1016/j.bbamcr.2013.07.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 06/04/2013] [Accepted: 07/15/2013] [Indexed: 01/06/2023]
Abstract
We recently identified several Ca(2+)-binding proteins (CaBP) from the S100 and annexin family to be regulated by TSH in FRTL-5 cells. Here, we study the regulation of S100A4, S100A6 and ANXA2 in primary human thyrocytes (PHT) derived from surrounding tissues (ST), cold benign thyroid nodules (CTN) and autonomously functioning thyroid nodules (AFTN). We investigated the expression and regulation of CaBP and the effect of their expression on Ca(2+) and TSHR signaling. We used an approach that accounts for the potential of an individual PHT culture to proliferate or to express thyroid differentiation features by assessing the expression of FOS and TPO. We found a strong correlation between the regulation of CaBP and the proliferation-associated transcription factor gene FOS. PKA and MEK1/2 were regulators of ANXA2 expression, while PI3-K and triiodothyronine were additionally involved in S100 regulation. The modulated expression of CaBP was reflected by changes in ATP-elicited Ca(2+) signaling in PHT. S100A4 increased the ratio of subsequent Ca(2+) responses and showed a Ca(2+) buffering effect, while ANXA2 affected the first Ca(2+) response to ATP. Overexpression of S100A4 led to a reduced activation of NFAT by TSH. Using S100A4 E33Q, D63N, F72Q and Y75K mutants we found that the effects of S100A4 expression on Ca(2+) signaling are mediated by protein interaction. We present evidence that TSH has the ability to fine-tune Ca(2+) signals through the regulation of CaBP expression. This represents a novel putative cross-regulating mechanism in thyrocytes that could affect thyrocyte signaling and physiology.
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Sukumaran P, Löf C, Kemppainen K, Kankaanpää P, Pulli I, Näsman J, Viitanen T, Törnquist K. Canonical transient receptor potential channel 2 (TRPC2) as a major regulator of calcium homeostasis in rat thyroid FRTL-5 cells: importance of protein kinase C δ (PKCδ) and stromal interaction molecule 2 (STIM2). J Biol Chem 2012; 287:44345-60. [PMID: 23144458 DOI: 10.1074/jbc.m112.374348] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mammalian non-selective transient receptor potential cation channels (TRPCs) are important in the regulation of cellular calcium homeostasis. In thyroid cells, including rat thyroid FRTL-5 cells, calcium regulates a multitude of processes. RT-PCR screening of FRTL-5 cells revealed the presence of TRPC2 channels only. Knockdown of TRPC2 using shRNA (shTRPC2) resulted in decreased ATP-evoked calcium peak amplitude and inward current. In calcium-free buffer, there was no difference in the ATP-evoked calcium peak amplitude between control cells and shTRPC2 cells. Store-operated calcium entry was indistinguishable between the two cell lines. Basal calcium entry was enhanced in shTRPC2 cells, whereas the level of PKCβ1 and PKCδ, the activity of sarco/endoplasmic reticulum Ca(2+)-ATPase, and the calcium content in the endoplasmic reticulum were decreased. Stromal interaction molecule (STIM) 2, but not STIM1, was arranged in puncta in resting shTRPC2 cells but not in control cells. Phosphorylation site Orai1 S27A/S30A mutant and non-functional Orai1 R91W attenuated basal calcium entry in shTRPC2 cells. Knockdown of PKCδ with siRNA increased STIM2 punctum formation and enhanced basal calcium entry but decreased sarco/endoplasmic reticulum Ca(2+)-ATPase activity in wild-type cells. Transfection of a truncated, non-conducting mutant of TRPC2 evoked similar results. Thus, TRPC2 functions as a major regulator of calcium homeostasis in rat thyroid cells.
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Affiliation(s)
- Pramod Sukumaran
- Department of Biosciences, Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
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Löf C, Sukumaran P, Viitanen T, Vainio M, Kemppainen K, Pulli I, Näsman J, Kukkonen JP, Törnquist K. Communication between the calcium and cAMP pathways regulate the expression of the TSH receptor: TRPC2 in the center of action. Mol Endocrinol 2012; 26:2046-57. [PMID: 23015753 DOI: 10.1210/me.2012-1171] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Transient receptor potential (TRP) cation channels are widely expressed and function in many physiologically important processes. Perturbations in the expression or mutations of the channels have implications for diseases. Many thyroid disorders, as excessive growth or disturbed thyroid hormone production, can be a result of dysregulated TSH signaling. In the present study, we found that of TRP canonicals (TRPCs), only TRPC2 was expressed in Fischer rat thyroid low-serum 5% cells (FRTL-5 cells). To investigate the physiological importance of the channel, we developed stable TRPC2 knockdown cells using short hairpin RNA (shTRPC2 cells). In these cells, the ATP-evoked entry of calcium was significantly decreased. This led to increased cAMP production, because inhibitory signals from calcium to adenylate cyclase 5/6 were decreased. Enhanced cAMP signaling projected to Ras-related protein 1-MAPK kinase 1 (MAPK/ERK kinase 1) pathway leading to phosphorylation of ERK1/2. The activated ERK1/2 pathway increased the expression of the TSH receptor. In contrast, secretion of thyroglobulin was decreased in shTRPC2 cells, due to improper folding and glycosylation of the protein. We show here a novel role for TRPC2 in regulating thyroid cell function.
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Affiliation(s)
- Christoffer Löf
- Department of Biosciences, Åbo Akademi University, Biocity, Tykistökatu 6A, 20520 Turku, Finland
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15
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Massart C, Hoste C, Virion A, Ruf J, Dumont JE, Van Sande J. Cell biology of H2O2 generation in the thyroid: investigation of the control of dual oxidases (DUOX) activity in intact ex vivo thyroid tissue and cell lines. Mol Cell Endocrinol 2011; 343:32-44. [PMID: 21683758 DOI: 10.1016/j.mce.2011.05.047] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 05/06/2011] [Accepted: 05/31/2011] [Indexed: 10/18/2022]
Abstract
H2O2 generation by dual oxidase (DUOX) at the apex of thyroid cells is the limiting factor in the oxidation of iodide and the synthesis of thyroid hormones. Its characteristics have been investigated using different in vitro models, from the most physiological thyroid slices to the particulate fraction isolated from transfected DUOX expressing CHO cells. Comparison of the models shows that some positive controls are thyroid specific (TSH) or require the substructure of the in vivo cells (MβCD). Other controls apply to all intact cell models such as the stimulation of the PIP(2) phospholipase C pathway by ATP acting on purinergic receptors, the activation of the Gq protein downstream (NaF), or surrogates of the intracellular signals generated by this cascade (phorbol esters for protein kinase C, Ca(++) ionophore for Ca(++)). Still, other controls, exerted by intracellular Ca(++) or its substitute Mn(++), the intracellular pH, or arachidonate bear directly on the enzyme. Iodide acts at the apical membrane of the cell through an oxidized form, presumably iodohexadecanal. Cooling of the cells to 22°C blocks the activation of the PIP(2) phospholipase C cascade. All these effects are reversible. Their kinetics and concentration-effect characteristics have been defined in the four models. A general scheme of the thyroid signaling pathways regulating this metabolism is proposed. The probes characterized could be applied to other H2O2 producing cells and to pathological material.
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Affiliation(s)
- C Massart
- Institute of Interdisciplinary Research (IRIBHM), University of Brussels, Campus Erasme, Route de Lennik 808, B 1070 Brussels, Belgium
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Hornung MW, Degitz SJ, Korte LM, Olson JM, Kosian PA, Linnum AL, Tietge JE. Inhibition of Thyroid Hormone Release from Cultured Amphibian Thyroid Glands by Methimazole, 6-Propylthiouracil, and Perchlorate. Toxicol Sci 2010; 118:42-51. [DOI: 10.1093/toxsci/kfq166] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Roger PP, van Staveren WCG, Coulonval K, Dumont JE, Maenhaut C. Signal transduction in the human thyrocyte and its perversion in thyroid tumors. Mol Cell Endocrinol 2010; 321:3-19. [PMID: 19962425 DOI: 10.1016/j.mce.2009.11.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 11/23/2009] [Accepted: 11/27/2009] [Indexed: 11/19/2022]
Abstract
The study of normal signal transduction pathways regulating the proliferation and differentiation of a cell type allows to predict and to understand the perversions of these pathways which lead to tumorigenesis. In the case of the human thyroid cell, three cascades are mostly involved in tumorigenesis: The pathways and genetic events affecting them are described. Caveats in the use of models and the interpretation of results are formulated and the still pending questions are outlined.
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Affiliation(s)
- Pierre P Roger
- I.R.I.B.H.M., Université Libre de Bruxelles, Campus Erasme, Route de Lennik 808, B - 1070 Bruxelles, Belgium
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18
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Calcium signaling of thyrocytes is modulated by TSH through calcium binding protein expression. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:352-60. [PMID: 20083144 DOI: 10.1016/j.bbamcr.2010.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 12/18/2009] [Accepted: 01/11/2010] [Indexed: 12/12/2022]
Abstract
TSH is an important stimulus to maintain thyroid epithelial differentiation. Impairment of TSH signal transduction can cause thyroid pathologies such as hot nodules, goiter and hyperthyroidism. In a gene expression study in Fischer rat thyroid cells (FRTL-5) using cDNA microarrays we found a TSH-dependent regulation of several calcium binding proteins, S100A4, S100A6 and annexin A6. Expression of these genes in FRTL-5 and regulation by TSH was confirmed with LightCycler qPCR and Western blotting. The differential expression of S100A4 was confirmed for cultured primary human thyrocytes. Calcium-imaging experiments showed that prestimulation with TSH attenuates ATP-elicited P2Y-mediated calcium signaling. Experiments with thapsigargin, TSH and calcium-free perfusion excluded an involvement of other purinergic receptors or an involvement of SERCA regulation. Instead, we find a correlation between S100A4 expression and the effects of TSH on calcium signaling. Overexpression of S100A4 in FRTL-5 and shRNA-mediated knockdown of S100A4 in follicular thyroid cancer cells (FTC133) confirm the ability of S100A4 to attenuate calcium signals. Under repeated stimulations with ATP the calcium retention of these cells is also modulated by S100A4, suggesting a role of S100A4 as calcium buffering protein. As a biological consequence of S100A4 overexpression we detected reduced ATP-stimulated cFos induction. Taken together, the results suggest that S100A4 and other calcium binding proteins are part of a signaling network connecting TSH signaling to calcium-mediated events which play a role in thyroid physiology like H2O2 production or even thyroid cancer.
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19
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20
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Rigutto S, Hoste C, Grasberger H, Milenkovic M, Communi D, Dumont JE, Corvilain B, Miot F, De Deken X. Activation of dual oxidases Duox1 and Duox2: differential regulation mediated by camp-dependent protein kinase and protein kinase C-dependent phosphorylation. J Biol Chem 2009; 284:6725-34. [PMID: 19144650 DOI: 10.1074/jbc.m806893200] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Dual oxidases were initially identified as NADPH oxidases producing H(2)O(2) necessary for thyroid hormone biosynthesis. The crucial role of Duox2 has been demonstrated in patients suffering from partial iodide organification defect caused by bi-allelic mutations in the DUOX2 gene. However, the Duox1 function in thyroid remains elusive. We optimized a functional assay by co-expressing Duox1 or Duox2 with their respective maturation factors, DuoxA1 and DuoxA2, to compare their intrinsic enzymatic activities under stimulation of the major signaling pathways active in the thyroid in relation to their membrane expression. We showed that basal activity of both Duox isoenzymes depends on calcium and functional EF-hand motifs. However, the two oxidases are differentially regulated by activation of intracellular signaling cascades. Duox1 but not Duox2 activity is stimulated by forskolin (EC(50) = 0.1 microm) via protein kinase A-mediated Duox1 phosphorylation on serine 955. In contrast, phorbol esters induce Duox2 phosphorylation via protein kinase C activation associated with high H(2)O(2) generation (phorbol 12-myristate 13-acetate EC(50) = 0.8 nm). These results were confirmed in human thyroid cells, suggesting that Duox1 is also involved in thyroid hormonogenesis. Our data provide, for the first time, detailed insights into the mechanisms controlling the activation of Duox1-2 proteins and reveal additional phosphorylation-mediated regulation.
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Affiliation(s)
- Sabrina Rigutto
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre Bruxelles, Brussels, Belgium.
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21
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Protective actions of human tissue kallikrein gene in transgenic rat hearts. Int Immunopharmacol 2008; 8:267-70. [PMID: 18182238 DOI: 10.1016/j.intimp.2007.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Revised: 08/31/2007] [Accepted: 09/06/2007] [Indexed: 10/22/2022]
Abstract
In this study, we used an experimental model of cardiac hypertrophy to explore the role of the kallikrein-kinin system (KKS) in cardiac protection in transgenic rats harboring the human tissue kallikrein gene, TGR(hKLK1). Tissue kallikrein cleaves low-molecular-weight kininogen to produce kinin peptides, which bind to kinin receptors and trigger a wide spectrum of biological effects. The transgene, under the control of the zinc-inducible metallothionein promoter, was expressed in most tissues including the heart, kidney, lung and brain. These animals were subjected to treatment with thyroid hormone in order to promote cardiac hypertrophy. Induction of cardiac hypertrophy revealed a marked protective effect caused by the expression of the kallikrein transgene, evidenced by the significantly reduced cardiac weight gain and the lower enhancement in the cardiac expression of atrial natriuretic peptide and collagen III, markers for hypertrophy and fibrosis, respectively. In conclusion, our data show that expression of tissue kallikrein exerts antihypertrophic and antifibrotic actions in the heart.
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22
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Costa MJ, Senou M, Van Rode F, Ruf J, Capello M, Dequanter D, Lothaire P, Dessy C, Dumont JE, Many MC, Van Sande J. Reciprocal negative regulation between thyrotropin/3',5'-cyclic adenosine monophosphate-mediated proliferation and caveolin-1 expression in human and murine thyrocytes. Mol Endocrinol 2007; 21:921-32. [PMID: 17202321 DOI: 10.1210/me.2006-0328] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The expression of caveolins is down-regulated in tissue samples of human thyroid autonomous adenomas and in the animal model of this disease. Because several cell types present in thyroid express caveolins, it remained unclear if this down-regulation occurs in thyrocytes and which are the mechanism and role of this down-regulation in the tumor context. Here we show that prolonged stimulation of isolated human thyrocytes by TSH/cAMP/cAMP-dependent protein kinase inhibits caveolins' expression. The expression of caveolins is not down-regulated by activators of other signaling pathways relevant to thyroid growth/function. Therefore, the down-regulation of caveolins' expression in autonomous adenomas is a direct consequence of the chronic activation of the TSH/cAMP pathway in thyrocytes. The down-regulation of caveolin-1 occurs at the mRNA level, with a consequent protein decrease. TSH/cAMP induces a transcription-dependent, translation-independent destabilization of the caveolin-1 mRNA. This effect is correlated to the known proliferative role of that cascade in thyrocytes. In vivo, thyrocytes of caveolin-1 knockout mice display enhanced proliferation. This demonstrates, for the first time, the in vivo significance of the specific caveolin-1 down-regulation by one mitogenic cascade and its relation to a human disease.
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Affiliation(s)
- Maria José Costa
- Institut de Recherche Interdisciplinaire, Campus Erasme, Université Libre de Bruxelles, 808 Route de Lennik, Building C, 1070 Brussels, Belgium
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23
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Dayem M, Navarro V, Marsault R, Darcourt J, Lindenthal S, Pourcher T. From the molecular characterization of iodide transporters to the prevention of radioactive iodide exposure. Biochimie 2006; 88:1793-806. [PMID: 16905238 DOI: 10.1016/j.biochi.2006.07.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 07/19/2006] [Indexed: 12/23/2022]
Abstract
In the event of a nuclear reactor accident, the major public health risk will likely result from the release and dispersion of volatile radio-iodines. Upon body exposure and food ingestion, these radio-iodines are concentrated in the thyroid, resulting in substantial thyroidal irradiation and accordingly causing thyroid cancers. Stable potassium iodide (KI) effectively blocks thyroid iodine uptake and is thus used in iodide prophylaxis for reactor accidents. The efficiency of KI is directly related to the physiological inhibition of the thyroid function in the presence of high plasma iodide concentrations. This regulation is called the Wolff-Chaikoff effect. However, to be fully effective, KI should be administered shortly before or immediately after radioiodine exposure. If KI is provided only several hours after exposure, it will elicit the opposite effect e.g. lead to an increase in the thyroid irradiation dose. To date, clear evaluation of the benefit and the potential toxicity of KI administration remain difficult, and additional data are needed. We outline in this review the molecular characterization of KI-induced regulation of the thyroid function. Significant advances in the knowledge of the iodide transport mechanisms and thyroid physiology have been made. Recently developed molecular tools should help clarify iodide metabolism and the Wolff-Chaikoff effect. The major goals are clarifying the factors which increase thyroid cancer risk after a reactor accident and improving the KI administration protocol. These will ultimately lead to the development of novel strategies to decrease thyroid irradiation after radio-iodine exposure.
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Affiliation(s)
- M Dayem
- Unité TIRO (Transporter in Imaging and Radiotherapy in Oncology), Commissariat à l'énergie atomique DSV-DIEP-SBTN, School of Medicine, University of Nice Sophia Antipolis, 28, avenue de Valombrose, 06107 Nice cedex, France
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Van Sande J, Dequanter D, Lothaire P, Massart C, Dumont JE, Erneux C. Thyrotropin stimulates the generation of inositol 1,4,5-trisphosphate in human thyroid cells. J Clin Endocrinol Metab 2006; 91:1099-107. [PMID: 16384841 DOI: 10.1210/jc.2005-1324] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
CONTEXT Dual activation by TSH of the phospholipase C and cAMP cascades has been reported in human thyroid cells. In contrast, Singh et al. reported convincing data in FRTL-5 thyrocytes arguing against such an effect in this model. Their data in FRTL-5 cells indicated no increase in inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] in response to TSH. Therefore, the authors questioned results previously obtained on human cells by cruder methodology. OBJECTIVE We investigated the formation of inositol phosphates by HPLC techniques in human thyroid slices to separate the inositol phosphate isomers. RESULTS Ins(1,4,5)P3, inositol 1,3,4-trisphosphate, and inositol 1,3,4,5-tetrakisphosphate were increased after TSH stimulation. The effect of TSH in human thyroid cells was reproduced by recombinant TSH and prevented by antibodies blocking the TSH receptor. Thyroid-stimulating antibodies at concentrations eliciting a cAMP response equivalent to TSH failed to stimulate inositol phosphate generation. CONCLUSIONS TSH, but not thyroid-stimulating antibodies, activates both cAMP and the phospholipase C cascade in human thyroid as now demonstrated by an increase in Ins(1,4,5)P3 and its inositol phosphate metabolites. Therefore, this effect cannot be extrapolated to the FRTL-5 cell line. The apparent discrepancy may be due to a difference between species (human vs. rat) or to the loss of the fresh tissue properties in a cell line. The dual effect of TSH in human cells, through cAMP on secretion of thyroid hormones and through the diacylglycerol, Ins(1,4,5)P3 Ca2+ pathway on thyroid hormone synthesis, implies the possible separation of these effects in thyroid disease.
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Affiliation(s)
- Jacqueline Van Sande
- Institute of Interdisciplinary Research, Campus Erasme Building C, 808 Route de Lennik, 1070 Brussels, Belgium
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25
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Costa MJ, Song Y, Macours P, Massart C, Many MC, Costagliola S, Dumont JE, Van Sande J, Vanvooren V. Sphingolipid-cholesterol domains (lipid rafts) in normal human and dog thyroid follicular cells are not involved in thyrotropin receptor signaling. Endocrinology 2004; 145:1464-72. [PMID: 14670987 DOI: 10.1210/en.2003-1432] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Partition of signaling molecules in sphingolipid-cholesterol-enriched membrane domains, among which are the caveolae, may contribute to signal transduction efficiency. In normal thyroid, nothing is known about a putative TSH/cAMP cascade compartmentation in caveolae or other sphingolipid-cholesterol-enriched membrane domains. In this study we show for the first time that caveolae are present in the apical membrane of dog and human thyrocytes: caveolin-1 mRNA presence is demonstrated by Northern blotting in primary cultures and that of the caveolin-1 protein by immunohistochemistry performed on human thyroid tissue. The TSH receptor located in the basal membrane can therefore not be located in caveolae. We demonstrate for the first time by biochemical methods the existence of sphingolipid-cholesterol-enriched domains in human and dog thyroid follicular cells that contain caveolin, flotillin-2, and the insulin receptor. We assessed a possible sphingolipid-cholesterol-enriched domains compartmentation of the TSH receptor and the alpha- subunit of the heterotrimeric G(s) and G(q) proteins using two approaches: Western blotting on detergent-resistant membranes isolated from thyrocytes in primary cultures and the influence of 10 mm methyl-beta-cyclodextrin, a cholesterol chelator, on basal and stimulated cAMP accumulation in intact thyrocytes. The results from both types of experiments strongly suggest that the TSH/cAMP cascade in thyroid cells is not associated with sphingolipid-cholesterol-enriched membrane domains.
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Affiliation(s)
- M J Costa
- Institute of Interdisciplinary Research, Free University of Brussels, School of Medicine, B-1070 Brussels, Belgium
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26
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Burnstock G, Knight GE. Cellular Distribution and Functions of P2 Receptor Subtypes in Different Systems. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 240:31-304. [PMID: 15548415 DOI: 10.1016/s0074-7696(04)40002-3] [Citation(s) in RCA: 581] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review is aimed at providing readers with a comprehensive reference article about the distribution and function of P2 receptors in all the organs, tissues, and cells in the body. Each section provides an account of the early history of purinergic signaling in the organ?cell up to 1994, then summarizes subsequent evidence for the presence of P2X and P2Y receptor subtype mRNA and proteins as well as functional data, all fully referenced. A section is included describing the plasticity of expression of P2 receptors during development and aging as well as in various pathophysiological conditions. Finally, there is some discussion of possible future developments in the purinergic signaling field.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Institute, Royal Free and University College Medical School, London NW3 2PF, United Kingdom
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27
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Emerson CH, Torres MST. Recombinant human thyroid-stimulating hormone: pharmacology, clinical applications and potential uses. BioDrugs 2003; 17:19-38. [PMID: 12534318 DOI: 10.2165/00063030-200317010-00003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The major functions of pituitary thyroid-stimulating hormone (TSH) are to maintain the biosynthesis and secretion of the thyroid hormones L-thyroxine (T4) and L-3,5,3'triidothyronine (T3). The TSH core contains two apoproteins, the alpha and beta subunits. The alpha subunit is identical to that of pituitary follitropin, pituitary lutropin and placental chorionic gonadotropin, whereas the beta subunit is unique. TSH is a glycoprotein; the glycoprotein components of the alpha and beta subunits account for more than 10% of their mass and are essential for normal thyrotropic action and intravascular kinetics. The hypothalamic tripeptide, TSH-releasing hormone (TRH) is required for optimum TSH biosynthesis, particularly as far as addition of the glycoprotein components is concerned. TRH deficiency is associated with secretion of TSH molecules that are appropriately measured in most assays but have reduced bioactivity. In previous years the TSH used in clinical practice was obtained and purified from bovine pituitaries. Bovine TSH was used to test thyroid function and to augment the uptake of radioiodine in patients with thyroid cancer. Bovine TSH has been largely abandoned as a clinical agent because of adverse immune reactions. A recombinant human TSH (rhTSH; Thyrogen), has been approved by the US FDA for diagnostic use in patients with thyroid cancer. The alpha and beta subunits of Thyrogen are identical to those of human pituitary TSH. Thyrogen has a specific activity of approximately 4 IU/mg and is a potent stimulator of T4, T3 and thyroglobulin (Tg) secretion in healthy volunteers. It also increases thyroid iodide uptake in patients with thyroid cancer or multinodular goitre and in volunteers, even those exposed to large amounts of stable iodide. Thyroid cancer patients who have been treated by thyroidectomy and radioiodine ablation but are at risk of harbouring residual thyroid cancer are candidates for Thyrogen administration to prepare them for whole body iodide scans and serum Tg measurements. In thyroidectomised thyroid cancer patients who are unable to secrete pituitary TSH upon thyroid hormone withdrawal, Thyrogen is the only acceptable method to prepare them for these procedures. Thyrogen has been used on a compassionate basis to prepare patients for radioiodine ablation. rhTSH, in addition to being useful in the management of patients with thyroid cancer, is potentially useful to test thyroid reserve and to aid in thyroid-related nuclear medicine procedures. In the future, TSH analogues that have superagonist or antagonist properties may become available as therapeutic agents.
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Affiliation(s)
- Charles H Emerson
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, Massachusetts 01655, USA.
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Marsigliante S, Elia MG, Di Jeso B, Greco S, Muscella A, Storelli C. Increase of [Ca(2+)](i) via activation of ATP receptors in PC-Cl3 rat thyroid cell line. Cell Signal 2002; 14:61-7. [PMID: 11747990 DOI: 10.1016/s0898-6568(01)00208-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In PC-Cl3 rat thyroid cell line, ATP and UTP provoked a transient increase in [Ca(2+)](i), followed by a lower sustained phase. Removal of extracellular Ca(2+) reduced the initial transient response and completely abolished the plateau phase. Thapsigargin (TG) caused a rapid rise in [Ca(2+)](i) and subsequent addition of ATP was without effect. The transitory activation of [Ca(2+)](i) was dose-dependently attenuated in cells pretreated with the specific inhibitor of phospholipase C (PLC), U73122. These data suggest that the ATP-stimulated increment of [Ca(2+)](i) required InsP(3) formation and binding to its specific receptors in Ca(2+) stores. Desensitisation was demonstrated with respect to the calcium response to ATP and UTP in Fura 2-loaded cells. Further studies were performed to investigate whether the effect of ATP on Ca(2+) entry into PC-Cl3 cells was via L-type voltage-dependent Ca(2+) channels (L-VDCC) and/or by the capacitative pathway. Nifedipine decreased ATP-induced increase on [Ca(2+)](i). Addition of 2 mM Ca(2+) induced a [Ca(2+)](i) rise after pretreatment of the cells with TG or with 100 microM ATP in Ca(2+)-free medium. These data indicate that Ca(2+) entry into PC-Cl3 stimulated with ATP occurs through both an L-VDCC and through a capacitative pathway. Using buffers with differing Na(+) concentrations, we found that the effects of ATP were dependent of extracellular Na(+), suggesting that a Na(+)/Ca(2+) exchange mechanism is also operative. These data suggest the existence, in PC-Cl3 cell line, of a P2Y purinergic receptor able to increase the [Ca(2+)](i) via PLC activation, Ca(2+) store depletion, capacitative Ca(2+) entry and L-VDCC activation.
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Affiliation(s)
- Santo Marsigliante
- Laboratory of Physiology, Department of Biology, University of Lecce, Lecce 73100, Italy.
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Bourke J, Abel K, Huxham G, Cooper V, Manley S. UTP-preferring P2 receptor mediates inhibition of sodium transport in porcine thyroid epithelial cells. Br J Pharmacol 1999; 127:1787-92. [PMID: 10482908 PMCID: PMC1566178 DOI: 10.1038/sj.bjp.0702733] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The effects of adenosine 5'-triphosphate (ATP), uridine 5'-triphosphate (UTP) and analogues on forskolin-stimulated absorption of Na+ by porcine thyroid epithelial cells were analysed in cultures grown as confluent monolayers on permeable supports in Transwell Ussing chambers. 2. 85% of the forskolin (10 microM)-stimulated short-circuit current was inhibited by phenamil (1 microM), which is a selective antagonist for epithelial type Na+ channels. 3. Phenamil-sensitive current was inhibited in a dose dependent manner by nucleotides added to the apical compartment of Ussing chambers. In contrast, the phenamil-resistant current, previously shown to represent anion secretion, was unaffected by nucleotides. 4. The order of potency (with EC50 values given in microM) was UTP (0.08)>>ATP (6.3)=uridine 5'-diphosphate (UDP) (6. 6)>2methyl-thio-adenosine-5'-triphosphate (2MeSATP) (84.5)>adenosine 5'-diphosphate (ADP) (147.8)>alpha,beta-methylene ATP (>150)>>adenosine (>1000). 5. P2 receptors mediating inhibition of sodium absorption were present on the apical membrane of the cells since addition of UTP (1-1000 microM) to the basal compartment of the Ussing chambers had little effect while subsequent addition to the apical compartment produced a normal response. 6. Cibachron blue (Reactive blue 2) (1-100 microM), an antagonist at some P2 receptor subtypes, inhibited phenamil sensitive current in a dose dependent manner with half maximal inhibition occurring at 14.25 microM. 7. Suramin (100 microM), pyridoxalphosphate-6-azophenyl-2', 4'-disulphonic acid (PPADS) (100 microM) and pyridoxal 5'-phosphate (P5P) (100 microM) showed only slight competitive antagonism against the response to UTP. 8 These results indicate that a UTP-preferring P2 receptor located on the apical membrane of thyroid epithelial cells mediates inhibition of Na+ absorption.
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Affiliation(s)
- J Bourke
- Department of Physiology and Pharmacology, The University of Queensland, St Lucia, Australia 4072
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30
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Rausell V, Fraser HM, Tobaruela M, del Rio-Garcia J, Smyth DG. Identification of the TRH-like peptides pGlu-Glu-Pro amide and pGlu-Phe-Pro amide in rat thyroid: regulation by thyroid status. REGULATORY PEPTIDES 1999; 81:55-60. [PMID: 10395408 DOI: 10.1016/s0167-0115(99)00017-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Rat thyroid contains thyrotropin-releasing hormone (TRH) and TRH-like peptides which react with TRH antisera. We have identified the TRH-like peptides in the thyroid and examined whether their levels are influenced by thyroid status. The peptides were extracted from the thyroid glands of five hyperthyroid rats and purified by ion-exchange chromatography on SP-Sephadex C25 and reversed-phase high performance liquid chromatography. The principal TRH-immunoreactive component exhibited the same retention on HPLC as synthetic pGlu-Glu-Pro amide and a secondary component corresponded to synthetic pGlu-Phe-Pro amide. In agreement with these assignments the main peptide was shown to be acidic when chromatographed on DEAE-Sephadex A25 and the second peptide neutral. The levels of TRH and TRH-like peptides in the thyroid were investigated in hyper-, hypo- and euthyroid rats. Hyperthyroidism was induced by chronic subcutaneous administration of triiodothyronine (T3) and hypothyroidism was produced by addition of propylthiouracil (PTU) to the drinking water. The amounts of the peptides were determined by radioimmunoassay with a TRH-antiserum, carried out after extraction from the tissues and purification by ion exchange chromatography. The mean concentration of TRH-like peptides in the thyroids of the hyperthyroid rats was 95.5+/-25.5 pmol/g, the mean concentration in the hypothyroid rats was 11.7+/-3.4 pmol/g, and in the euthyroid rats 17.6+/-3.2 pmol/g. The concentrations of TRH were less influenced by thyroid status: the values in hyper-, hypo- and euthyroid rats were 47.5+/-9.4, 42.1+/-6.3, and 17.2+/-1.6 pmol/g respectively. The results show that the levels of the TRH-like peptides in rat thyroid are highly sensitive to thyroid status, suggesting a possible involvement in thyroid regulation.
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Affiliation(s)
- V Rausell
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Murcia, Espinardo, Spain
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31
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Wu Z, Biro PA, Mirakian R, Hammond L, Curcio F, Ambesi-Impiombato FS, Bottazzo GF. HLA-DMB expression by thyrocytes: indication of the antigen-processing and possible presenting capability of thyroid cells. Clin Exp Immunol 1999; 116:62-9. [PMID: 10209506 PMCID: PMC1905228 DOI: 10.1046/j.1365-2249.1999.00831.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression of HLA class II molecules on thyrocytes is a characteristic feature of autoimmune thyroid disease and may lead the thyroid cells to present autoantigens to CD4+ T lymphocytes. Since HLA-DM is a critical molecule in class II-restricted antigen processing and presentation, we assessed the expression of HLA-DMB, -invariant chain (Ii), class II transactivator (CIITA) and DRA in an untransformed, pure thyrocyte strain HTV-59A. Here we report that both HLA-DMB mRNA and the protein are expressed in thyrocytes and that CIITA expression is enhanced by interferon-gamma (IFN-gamma) treatment and occurs before DMB, Ii and DRA up-regulation, suggesting CIITA expression is a requirement for antigen processing in thyrocytes. These results indicate that thyrocytes are capable of antigen processing and possibly antigen presentation to T cells.
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Affiliation(s)
- Z Wu
- Department of Immunology, St Bartholomew's, London, UK
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32
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Demeure MJ, Doffek KM, Wilson SD. Defective thyrotropin receptor G-protein cyclic adenosine monophosphate signaling mechanism in the FTC human follicular thyroid cancer cell line. Surgery 1997; 122:1195-201; discussion 1201-2. [PMID: 9426438 DOI: 10.1016/s0039-6060(97)90227-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Several studies report the effect of thyrotropin (thyroid-stimulating hormone [TSH]) on FTC-133) and aggressively invasive (FTC-238) clones of a human follicular thyroid cancer cell line. Specifically, TSH induces fibronectin secretion by FTC-133, possibly as a result of increased cyclic adenosine monophosphate (cAMP), yet induces in vitro invasion through a protein kinase C-dependent mechanism. In normal thyrocytes, TSH activates cAMP through a stimulatory G-protein (Gs)-linked pathway. In the FTC model we studied the effect of TSH on adenylate cyclase activation. METHODS TSH receptor (TSH-R) mRNA was studied by reverse transcriptase polymerase chain reaction. Fibronectin transcription was analyzed by Northern blot and densitometry. cAMP levels were determined by an enzyme immunoassay. Gs alpha expression was determined by Western blot and a possible activating mutation at position 201 in Gs alpha sought by direct sequencing. RESULTS Reverse transcriptase polymerase chain reaction confirmed the presence of TSH-R mRNA in FTC-133 and FTC-238. TSH did not increase transcription of fibronectin mRNA. FTC-133 cells exhibited higher cAMP levels than did FTC-238 cells: 30.4 +/- 8.0 versus 13.0 +/- 3.5 femtomoles/10(4) cells (mean +/- SD; p < 0.001, Mann-Whitney rank-sum test). TSH did not raise cAMP levels in either clone. Gs alpha expression is equal in both cell lines and is not increased by TSH; sequencing showed no position 201 mutations in Gs alpha. CONCLUSIONS Prototypical TSH-Gs-cAMP signal transduction is not functional in FTC-133 or FTC-238. Our findings implicate perturbation in TSH-R.
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Affiliation(s)
- M J Demeure
- Department of Surgery, Medical College of Wisconsin, Milwaukee 53226, USA
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33
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Schöfl C, Rössig L, Mader T, Börger J, Pötter E, von zur Mühlen A, Brabant G. Impairment of ATP-induced Ca2+ -signalling in human thyroid cancer cells. Mol Cell Endocrinol 1997; 133:33-9. [PMID: 9359470 DOI: 10.1016/s0303-7207(97)00141-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Extracellular nucleotides like ATP that activate the Ca2+ -phosphatidylinositol (PI) signalling pathway have been suggested to participate in the regulation of normal human thyroid function. We examined, whether P2y-purinergic receptors are expressed on human thyroid cancer cells and whether post-receptor Ca2+ signalling is altered by malignant transformation. Extracellular ATP caused a biphasic increase in cytosolic free Ca2+ ([Ca2+]i) in normal human thyrocytes and in human follicular (FTC) and papillary (PTC) thyroid carcinoma cells. In FTC and PTC cell lines the dose-response curves for ATP-induced changes in [Ca2+]i were shifted to the right when compared with normal thyrocytes, whereas in undifferentiated thyroid carcinoma (UTC) cells even high concentrations of ATP (500 microM) failed to stimulate a rise in [Ca2+]i. By contrast, ATP stimulated inositol 1,4,5-trisphosphate (IP3) formation and capacitative Ca2+ entry was operational as judged by thapsigargin in normal thyrocytes and all thyroid cancer cells. Thus, P2y-purinergic receptors are expressed on thyroid tumor cells independent of degree of differentiation. In UTC cells, however, impairment in the Ca2+ -phosphatidylinositol (PI) signalling cascade occurs distal to the formation of IP3 and proximal to the activation of capacitative Ca2+ entry. Disturbed ATP-induced Ca2+ -signalling and alterations in the Ca2+ -PI signalling cascade may contribute to decreased expression or loss of specific thyroid functions in thyroid cancer cells.
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Affiliation(s)
- C Schöfl
- Abteilung Klinische Endokrinologie, Medizinische Hochschule Hannover, Germany
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34
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Broecker M, Mayr GW, Derwahl M. Suppression of thyrotropin receptor-G protein-phospholipase C coupling by activation of protein kinase C in thyroid carcinoma cells. Endocrinology 1997; 138:3787-96. [PMID: 9275066 DOI: 10.1210/endo.138.9.5385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In human thyroid follicular cells TSH exerts its action on growth and function at least via two distinct pathways, the adenylate cyclase cascade and the phospholipase Cbeta (PLCbeta)-mediated inositol phosphate generation. We investigated the effect of TSH on activation of phosphoinositide hydrolysis and inositol phosphate generation by PLCbeta in HTh74 thyroid carcinoma cells that express functional TSH receptors and in HTC-TSHr thyroid carcinoma cells that are devoid of endogenous TSH receptors but express recombinant human TSH receptors. In both cell lines, TSH up to concentrations of 300 mU/ml failed to stimulate myo-inositol 1,4,5-trisphosphate and myo-inositol-tetrakisphosphate generation, but led to a decrease in these compounds within 1 min of stimulation. However, ATP and bradykinin increased concentrations of inositol phosphates in both thyroid carcinoma cell lines. In contrast, in differentiated FRTL5 thyroid cell line and CHO-TSHr cell line expressing recombinant human TSH receptors, TSH elicited a significant increase in myo-inositol 1,4,5-trisphosphate and its metabolic derivatives. However, when HTC-TSHr cells were pretreated with calphostin C or staurosporine, inhibitors of protein kinase C, a TSH concentration of 20 mU/ml enhanced generation of inositol phosphates in these cells. From our data we conclude that in HTC-TSHr and HTh74 thyroid carcinoma cells, the coupling within the TSH receptor-Gq protein-PLCbeta signaling pathway is impaired compared to that in nontransformed cells. It is conceivable that this is at least in part dependent on the level of protein kinase C activation in these cells.
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Affiliation(s)
- M Broecker
- Department of Medicine, Ruhr University, Bochum, Germany
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35
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Allgeier A, Laugwitz KL, Van Sande J, Schultz G, Dumont JE. Multiple G-protein coupling of the dog thyrotropin receptor. Mol Cell Endocrinol 1997; 127:81-90. [PMID: 9099903 DOI: 10.1016/s0303-7207(96)03996-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated, in dog thyroid membranes, the ability of the dog thyrotropin (TSH) receptor to interact with the endogenous G proteins expressed in this tissue. Activation of the receptor led to increased incorporation of the photoreactive GTP analog [alpha-(32)P]GTP azidoanilide into immunoprecipitated alpha subunits of three G protein families: G(s), G(q/11), G(i/o). This effect was not due to a general loss of receptor G protein specificity since carbamylcholine, in the same membrane preparations, only stimulated the binding of the GTP analog to the alpha subunits of G(q/11) proteins. To investigate the multiple coupling of the dog TSH receptor in intact cells, cyclic AMP accumulation, IP(3) formation and (45)Ca2+ efflux experiments were performed. When thyrocytes were pretreated with pertussis toxin (PTX), the TSH receptor-mediated accumulation of cAMP increased by approximately 45% with TSH at 1 mU/ml, suggesting that the TSH receptor coupled to both G(s) and G(i) in vivo. On the other hand, no increase in IP(3) accumulation nor Ca2+ efflux was observed in the presence of thyrotropin. These data in intact cells are thus in contradiction with those obtained in membranes, suggesting that receptor-mediated transmembrane signalling may implicate a specificity which itself may reflect a localization and organization of the different components (receptors, G proteins, ...) in the plasma membrane of intact cells. As in some cells, G(i) activates mitogenesis by hormone activated G-protein-coupled receptors, we tested its role in the stimulation by TSH of the proliferation of thyrocytes. This was not affected by PTX, suggesting that the mitogenic effect of TSH does not involve G(i)-proteins.
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Affiliation(s)
- A Allgeier
- Institute of Interdisciplinary Research, University of Brussels, Belgium
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36
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Singh J, Hunt P, Eggo MC, Sheppard MC, Kirk CJ, Michell RH. Thyroid-stimulating hormone rapidly stimulates inositol polyphosphate formation in FRTL-5 thyrocytes without activating phosphoinositidase C. Biochem J 1996; 316 ( Pt 1):175-82. [PMID: 8645202 PMCID: PMC1217319 DOI: 10.1042/bj3160175] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The thyroid-stimulating hormone (TSH) receptor is widely regarded as one of a limited number of G-protein-coupled receptors that activate both adenylate cyclase and phosphoinositidase C (PIC) via G-proteins, but the existing experimental evidence for TSH-stimulated PtdIns(4,5)P2 hydrolysis remains inconclusive. We have compared the effects of TSH and of ATP (acting via P2-purinergic receptors) on the inositol lipids and polyphosphates of [2-3H]inositol-labelled FRTL-5 rat thyroid cells. ATP initiated a rapid decrease in 3H-labelled PtdIns4P and PtdIns(4,5)P2, whereas TSH did not. Stimulation with ATP and, less consistently, with noradrenaline (acting via alpha-adrenergic receptors) provoked rapid formation of Ins(1,4,5)P3, Ins(1,3,4,5)P4, Ins(1,3,4)P3 and Ins(1,4)P2, confirming activation of PtdIns(4,5)P2 hydrolysis. No concentration of TSH provoked detectable accumulation of Ins(1,4,5)P3 or Ins(1,4)P2 during the first few minutes of stimulation. However, an InsP3 [with the chromatographic properties of Ins(1,3,4)P3] and two InsP4 isomers [neither of which was Ins(1,3,4,5)P4] accumulated quickly in TSH-stimulated cells. ATP immediately provoked a large increase in intracellular calcium concentration ([Ca2+]i) in Indo 1-AM-loaded cells. TSH provoked a small and delayed [Ca2+]i elevation in only some experiments. We therefore confirm that activation of P2-purinergic receptors and alpha 1-adrenergic receptors provokes PIC activation, an accumulation of Ins(1,4,5)P3 and its metabolites and rapid [Ca2+]i mobilization in FRTL-5 cells. By contrast, TSH provokes no rapid PIC-catalysed PtdIns(4,5)P2 hydrolysis or immediate [Ca2+]i mobilization. These results fail to support the widespread view that the TSH receptor of FRTL-5 cells signals, in part, through PIC activation. Our results suggest that TSH activates another, still undefined, mechanism that causes accumulation of an InsP3 and two isomers of InsP4.
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Affiliation(s)
- J Singh
- Department of Medicine, University of Birmingham, U.K
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37
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Yanagita Y, Okajima F, Sho K, Nagamachi Y, Kondo Y. An adenosine derivative cooperates with TSH and Graves' IgG to induce Ca2+ mobilization in single human thyroid cells. Mol Cell Endocrinol 1996; 118:47-56. [PMID: 8735590 DOI: 10.1016/0303-7207(96)03765-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Digital video imaging indicated that about 80% of fura-2-loaded single human thyroid cells responded to TSH, resulting in an increase in intracellular Ca2+ concentration ([Ca2+]i). Most of the TSH-sensitive cells further responded to N6-(L-2-phenylisopropyl)-adenosine (PIA) showing a transient [Ca2+]i rise in a PIA dose-dependent manner. Addition of PIA prior to TSH administration had no effect or showed only a slight [Ca2+]i increase, but in about 80% of the cells, regardless of the response to PIA, the addition of TSH after PIA resulted in a higher transient [Ca2+]i response than that in the absence of PIA. Inactivation of Gi/G(o) by pertussis toxin (PTX) treatment markedly reduced the effect of PIA on TSH action to the level induced by PIA alone. Immunoglobulin fractions obtained from two Graves' patients with high TSAb (antibody activity measured by cAMP response) activity induced [Ca2+]i increase and cooperated with PIA. Under the same conditions, TSH-dependent cAMP accumulation was inhibited by PIA. These results suggest that adenosine Ai receptor is expressed in human thyroid cells in primary culture as well as in FRTL-5 rat thyroid cells, and that in the presence of adenosine. TSH or Graves' IgG signal tends to be directed to the Ca2+ pathway in the human thyroid.
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Affiliation(s)
- Y Yanagita
- Laboratory of Signal Transduction, Gunma University, Maebashi, Japan
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38
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Abstract
Several growth factors may stimulate proliferation of thyroid cells. This effect has, in part, been dependent on calcium entry. In the present study using FRTL-5 cells, we show that in addition to its effect on calcium fluxes, ATP acts as a comitogen in these cells. In medium containing 5% serum, but no TSH, ATP stimulated the incorporation of 3H-thymidine in a dose- and time-dependent manner in the cells. At least a 24-h incubation with ATP was necessary to observe the enhanced (30-50%) incorporation of 3H-thymidine and an increased (30%) cell number. The effect of ATP was dependent on insulin in the incubation medium. Furthermore, ATP enhanced the TSH-mediated incorporation of 3H-thymidine. The effect of ATP was apparently mediated via a G-protein dependent mechanism, as no stimulation of thymidine incorporation was observed in cells treated with pertussis toxin. The effect of ATP was not dependent on the activation of protein kinase C (PKC), as ATP was effective in cells with downregulated PKC. ATP rapidly phosphorylated mitogen activated protein (MAP) kinase in FRTL-5 cells. In addition, ATP stimulated the expression of a 62 kDa c-fos dependent protein in a dose- and time-dependent manner. Our results thus suggest that extracellular ATP, in the presence of insulin, may be a cofactor in the regulation of thyroid cell proliferation, probably by phosphorylating MAP kinase and stimulating the expression of c-fos.
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Affiliation(s)
- K Törnquist
- Department of Biosciences, University of Helsinki, Finland
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39
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Laugwitz KL, Allgeier A, Offermanns S, Spicher K, Van Sande J, Dumont JE, Schultz G. The human thyrotropin receptor: a heptahelical receptor capable of stimulating members of all four G protein families. Proc Natl Acad Sci U S A 1996; 93:116-20. [PMID: 8552586 PMCID: PMC40189 DOI: 10.1073/pnas.93.1.116] [Citation(s) in RCA: 218] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Thyrotropin is the primary hormone that, via one heptahelical receptor, regulates thyroid cell functions such as secretion, specific gene expression, and growth. In human thyroid, thyrotropin receptor activation leads to stimulation of the adenylyl cyclase and phospholipase C cascades. However, the G proteins involved in thyrotropin receptor action have been only partially defined. In membranes of human thyroid gland, we immunologically identified alpha subunits of the G proteins Gs short, Gs long, Gi1, Gi2, Gi3, G(o) (Go2 and another form of Go, presumably Go1), Gq, G11, G12, and G13. Activation of the thyrotropin (TSH) receptor by bovine TSH led to increased incorporation of the photoreactive GTP analogue [alpha-32P]GTP azidoanilide into immunoprecipitated alpha subunits of all G proteins detected in thyroid membranes. This effect was receptor-dependent and not due to direct G protein stimulation because it was mimicked by TSH receptor-stimulating antibodies of patients suffering from Grave disease and was abolished by a receptor-blocking antiserum from a patient with autoimmune hypothyroidism. The TSH-induced activation of individual G proteins occurred with EC50 values of 5-50 milliunits/ml, indicating that the activated TSH receptor coupled with similar potency to different G proteins. When human thyroid slices were pretreated with pertussis toxin, the TSH receptor-mediated accumulation of cAMP increased by approximately 35% with TSH at 1 milliunits/ml, indicating that the TSH receptor coupled to Gs and G(i). Taken together, these findings show that, at least in human thyroid membranes, in which the protein is expressed at its physiological levels, the TSH receptor resembles a naturally occurring example of a general G protein-activating receptor.
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Affiliation(s)
- K L Laugwitz
- Institut für Pharmakologie, Freie Universität Berlin, Germany
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40
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Törnquist K, Ekokoski E. Evidence for a pertussis toxin sensitive calcium entry pathway in thyroid FRTL-5 cells. J Cell Physiol 1995; 164:142-7. [PMID: 7790385 DOI: 10.1002/jcp.1041640118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Receptor-mediated calcium entry was investigated in Fura 2 loaded FRTL-5 cells. The purinergic agonist ATP activated the release of sequestered calcium and the entry of extracellular calcium. Downregulation of protein kinase C (PKC) substantially enhanced the ATP-evoked calcium entry. Pretreatment of the cells with pertussis toxin (Ptx) decreased the ATP-evoked calcium entry by 56% and the release of sequestered calcium by 34%. In PKC-downregulated cells, the effect of Ptx treatment on the ATP-evoked increase in [Ca2+]i was 73% and 44%, respectively. Phorbol myristic acetate (PMA) decreased the ATP-evoked calcium entry to the same extent as Ptx. In Ptx-treated cells, the ATP-evoked influx of 45Ca2+ was attenuated. Stimulation of the cells with P2p-purinergic agonist GTP evoked no entry of calcium, although GTP released the same amount of sequestered calcium as did ATP. PKC downregulation or pretreatment with Ptx had no effects on the GTP-evoked responses, whereas PMA decreased the GTP-evoked release of calcium. We conclude that the ATP-activated rapid calcium entry pathway is a second messenger-operated calcium channel.
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Affiliation(s)
- K Törnquist
- Department of Zoology, University of Helsinki, Finland
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41
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Sande J, Swillens S, Gerard C, Allgeier A, Massart C, Vassart G, Dumont JE. In Chinese Hamster Ovary K1 Cells Dog and Human Thyrotropin Receptors Activate Both the Cyclic AMP and the Phosphatidylinositol 4,5-Bisphosphate Cascades in the Presence of Thyrotropin and the Cyclic AMP Cascade in Its Absence. ACTA ACUST UNITED AC 1995. [DOI: 10.1111/j.1432-1033.1995.0338k.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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42
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Curcio F, Ambesi-Impiombato FS, Perrella G, Coon HG. Long-term culture and functional characterization of follicular cells from adult normal human thyroids. Proc Natl Acad Sci U S A 1994; 91:9004-8. [PMID: 8090760 PMCID: PMC44735 DOI: 10.1073/pnas.91.19.9004] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We have obtained long-term cultures of differentiated proliferating follicular cells from normal adult human thyroid glands. In vitro growth of such human cells has been sustained by a modified F-12 medium, supplemented with bovine hypothalamus and pituitary extracts and no added thyrotropin. Cultures have been expanded, cloned, frozen, successfully retrieved, and characterized. Functional characterization of these cells shows constitutive thyroglobulin production and release and thyrotropin-dependent adenosine 3',5'-cyclic monophosphate production, the latter apparently not associated with significant increases in DNA synthesis or cell proliferation. Genetic characterization of these cells by chromosome counting showed the normal diploid chromosome number. The ability to cultivate differentiated human thyroid follicular cells in long-term culture opens possibilities for investigating the transduction pathways of thyrotropin stimulation in normal and pathological human tissues, developing clinically relevant in vitro assays, and considering cellular and molecular therapies.
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Affiliation(s)
- F Curcio
- Istituto di Patologia Clinica e Sperimentale, Facoltà di Medicina, Universitá degli Studi di Udine, Italy
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43
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Ito E, Oka K, Etcheberrigaray R, Nelson TJ, McPhie DL, Tofel-Grehl B, Gibson GE, Alkon DL. Internal Ca2+ mobilization is altered in fibroblasts from patients with Alzheimer disease. Proc Natl Acad Sci U S A 1994; 91:534-8. [PMID: 8290560 PMCID: PMC42983 DOI: 10.1073/pnas.91.2.534] [Citation(s) in RCA: 250] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The recent demonstration of K+ channel dysfunction in fibroblasts from Alzheimer disease (AD) patients and past observations of Ca(2+)-mediated K+ channel modulation during memory storage suggested that AD, which is characterized by memory loss and other cognitive deficits, might also involve dysfunction of intracellular Ca2+ mobilization. Bombesin-induced Ca2+ release, which is inositol trisphosphate-mediated, is shown here to be greatly enhanced in AD fibroblasts compared with fibroblasts from control groups. Bradykinin, another activator of phospholipase C, elicits similar enhancement of Ca2+ signaling in AD fibroblasts. By contrast, thapsigargin, an agent that releases Ca2+ by direct action on the endoplasmic reticulum, produced no differences in Ca2+ increase between AD and control fibroblasts. Depolarization-induced Ca2+ influx data previously demonstrated the absence of between-group differences of Ca2+ pumping and/or buffering. There was no correlation between the number of passages in tissue culture and the observed Ca2+ responses. Furthermore, cells of all groups were seeded and analyzed at the same densities. Radioligand binding experiments indicated that the number and affinity of bombesin receptors cannot explain the observed differences. These and previous observations suggest that the differences in bombesin and bradykinin responses in fibroblasts and perhaps other cell types are likely to be due to alteration of inositol trisphosphate-mediated release of intracellular Ca2+.
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Affiliation(s)
- E Ito
- Laboratory of Adaptive Systems, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
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44
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Féliers D, Pavlovic-Hournac M. Species differences of the thyroid protein kinase C heterogeneity. Thyroid 1994; 4:459-65. [PMID: 7711511 DOI: 10.1089/thy.1994.4.459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Protein kinase C (PKC), the mediator of the phosphoinositide transduction pathway, is a family of at least 11 isozymes and its heterogeneity has been described in many tissues and cells. We studied here the heterogeneity of PKC in thyroid glands from three different species, rat, pig, and dog. By combining immunological and biochemical approaches, we identified in rat thyroids, the PKC alpha, beta II, delta, epsilon, and zeta subspecies, in pig thyroids, the alpha, epsilon, and zeta isozymes, and in dog thyroids, only the alpha and zeta isozymes. The observed species differences of the thyroid gland PKC heterogeneity could be related to the reported species differences in the activation of the phosphoinositide regulatory cascade by TSH and other thyroid cell regulators.
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Affiliation(s)
- D Féliers
- Institut National de la Santé et de la Recherche Médicale, Unité 96, Le Kremlin-Bicêtre, France
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45
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Törnquist K, Ahlström M. Modulatory effect of cyclic AMP on calcium fluxes in FRTL-5 cells. J Cell Physiol 1993; 157:625-30. [PMID: 8253873 DOI: 10.1002/jcp.1041570323] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The aim of the present study was to investigate the effect of cAMP on calcium fluxes in Fura 2 loaded thyroid FRTL-5 cells. Preincubating the cells with the phosphodiesterase inhibitor Ro-201724 decreased the ATP-stimulated entry of calcium, while having no effect on the release of sequestered calcium. Pretreatment with forskolin decreased both the release of sequestered calcium and the entry of calcium in response to ATP. We then incubated the cells with phenylisopropyl adenosine (PIA), a P2i-receptor agonist earlier shown to decrease cAMP in FRTL-5 cells. Although we did not observe a decrease in cellular cAMP after PIA, the ATP-evoked calcium response was enhanced. Forskolin decreased calcium entry induced by thapsigargin, a Ca(2+)-ATPase inhibitor, but forskolin had no effect on the thapsigargin-evoked release of sequestered calcium. Addition of calcium to cells stimulated with ATP in a calcium-free buffered resulted in a rapid influx of calcium. This response in [Ca2+]i was decreased in cells pretreated with forskolin. In cells stimulated with thapsigargin, the increase in [Ca2+]i after addition of calcium was inhibited in part by forskolin and enhanced by PIA. The results suggest that cAMP may regulate calcium fluxes in FRTL-5 cells. Furthermore, PIA increased agonist-induced calcium entry through a presently unknown mechanism.
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Affiliation(s)
- K Törnquist
- Department of Zoology, University of Helsinki, Finland
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Raspé E, Dumont JE. Robert Feulgen Lecture 1991. Control and role of major signalling cascades of the thyrocyte. ACTA ACUST UNITED AC 1992; 26:1-29. [PMID: 1362463 DOI: 10.1016/s0079-6336(11)80074-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- E Raspé
- Institut de Recherche Interdisciplinaire, Faculté de Médecine, Université de Bruxelles, Belgium
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