1
|
Martin JV, Sarkar PK. Nongenomic roles of thyroid hormones and their derivatives in adult brain: are these compounds putative neurotransmitters? Front Endocrinol (Lausanne) 2023; 14:1210540. [PMID: 37701902 PMCID: PMC10494427 DOI: 10.3389/fendo.2023.1210540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 08/02/2023] [Indexed: 09/14/2023] Open
Abstract
We review the evidence regarding the nongenomic (or non-canonical) actions of thyroid hormones (thyronines) and their derivatives (including thyronamines and thyroacetic acids) in the adult brain. The paper seeks to evaluate these compounds for consideration as candidate neurotransmitters. Neurotransmitters are defined by their (a) presence in the neural tissue, (b) release from neural tissue or cell, (c) binding to high-affinity and saturable recognition sites, (d) triggering of a specific effector mechanism and (e) inactivation mechanism. Thyronines and thyronamines are concentrated in brain tissue and show distinctive patterns of distribution within the brain. Nerve terminals accumulate a large amount of thyroid hormones in mature brain, suggesting a synaptic function. However, surprisingly little is known about the potential release of thyroid hormones at synapses. There are specific binding sites for thyroid hormones in nerve-terminal fractions (synaptosomes). A notable cell-membrane binding site for thyroid hormones is integrin αvβ3. Furthermore, thyronines bind specifically to other defined neurotransmitter receptors, including GABAergic, catecholaminergic, glutamatergic, serotonergic and cholinergic systems. Here, the thyronines tend to bind to sites other than the primary sites and have allosteric effects. Thyronamines also bind to specific membrane receptors, including the trace amine associated receptors (TAARs), especially TAAR1. The thyronines and thyronamines activate specific effector mechanisms that are short in latency and often occur in subcellular fractions lacking nuclei, suggesting nongenomic actions. Some of the effector mechanisms for thyronines include effects on protein phosphorylation, Na+/K+ ATPase, and behavioral measures such as sleep regulation and measures of memory retention. Thyronamines promptly regulate body temperature. Lastly, there are numerous inactivation mechanisms for the hormones, including decarboxylation, deiodination, oxidative deamination, glucuronidation, sulfation and acetylation. Therefore, at the current state of the research field, thyroid hormones and their derivatives satisfy most, but not all, of the criteria for definition as neurotransmitters.
Collapse
Affiliation(s)
- Joseph V. Martin
- Biology Department, Center for Computational and Integrative Biology, Rutgers University, Camden, NJ, United States
| | - Pradip K. Sarkar
- Department of Basic Sciences, Parker University, Dallas, TX, United States
| |
Collapse
|
2
|
Moffett SX, Klein EA, Brannigan G, Martin JV. L-3,3',5-triiodothyronine and pregnenolone sulfate inhibit Torpedo nicotinic acetylcholine receptors. PLoS One 2019; 14:e0223272. [PMID: 31584962 PMCID: PMC6777777 DOI: 10.1371/journal.pone.0223272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/17/2019] [Indexed: 11/19/2022] Open
Abstract
The nicotinic acetylcholine receptor (nAChR) is an excitatory pentameric ligand-gated ion channel (pLGIC), homologous to the inhibitory γ-aminobutyric acid (GABA) type A receptor targeted by pharmaceuticals and endogenous sedatives. Activation of the GABAA receptor by the neurosteroid allopregnanolone can be inhibited competitively by thyroid hormone (L-3,3’,5-triiodothyronine, or T3), but modulation of nAChR by T3 or neurosteroids has not been investigated. Here we show that allopregnanolone inhibits the nAChR from Torpedo californica at micromolar concentrations, as do T3 and the anionic neurosteroid pregnenolone sulfate (PS). We test for the role of protein and ligand charge in mediated receptor inhibition by varying pH in a narrow range around physiological pH. We find that both T3 and PS become less potent with increasing pH, with remarkably similar trends in IC50 when T3 is neutral at pH < 7.3. After deprotonation of T3 (but no additional deprotonation of PS) at pH 7.3, T3 loses potency more slowly with increasing pH than PS. We interpret this result as indicating the negative charge is not required for inhibition but does increase activity. Finally, we show that both T3 and PS affect nAChR channel desensitization, which may implicate a binding site homologous to one that was recently indicated for accelerated desensitization of the GABAA receptor by PS.
Collapse
Affiliation(s)
- Steven X. Moffett
- Center for Computational and Integrative Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
| | - Eric A. Klein
- Center for Computational and Integrative Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
- Department of Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
| | - Grace Brannigan
- Center for Computational and Integrative Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
- Department of Physics, Rutgers University—Camden, Camden, New Jersey, United States of America
| | - Joseph V. Martin
- Center for Computational and Integrative Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
- Department of Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
- * E-mail:
| |
Collapse
|
3
|
Köhrle J, Biebermann H. 3-Iodothyronamine-A Thyroid Hormone Metabolite With Distinct Target Profiles and Mode of Action. Endocr Rev 2019; 40:602-630. [PMID: 30649231 DOI: 10.1210/er.2018-00182] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 12/20/2018] [Indexed: 12/14/2022]
Abstract
The rediscovery of the group of thyronamines (TAMs), especially the first detailed description of their most prominent congener 3-iodothyronamine (3T1AM) 14 years ago, boosted research on this thyroid hormone metabolite tremendously. TAMs exert actions partly opposite to and distinct from known functions of thyroid hormones. These fascinating metabolic, anapyrexic, cytoprotective, and brain effects quickly evoked the hope to use hormone-derived TAMs as a therapeutic option. The G protein-coupled receptor (GPCR) TAAR1, a member of the trace amine-associated receptor (TAAR) family, was identified as the first target and effector of TAM action. The initial enthusiasm on pharmacological actions of exogenous TAMs elicited many questions, such as sites of biosynthesis, analytics, modes of action, inactivation, and role of TAMs in (patho)physiology. Meanwhile, it became clear that TAMs not only interact with TAAR1 or other TAAR family members but also with several aminergic receptors and non-GPCR targets such as transient receptor potential channels, mitochondrial proteins, and the serum TAM-binding protein apolipoprotein B100, thus classifying 3T1AM as a multitarget ligand. The physiological mode of action of TAMs is still controversial because regulation of endogenous TAM production and the sites of its biosynthesis are not fully elucidated. Methods for 3T1AM analytics need further validation, as they revealed different blood and tissue concentrations depending on detection principles used such as monoclonal antibody-based immunoassay vs liquid chromatography- matrix-assisted laser desorption/ionization mass spectrometry or time-of-flight mass spectrometry. In this review, we comprehensively summarize and critically evaluate current basic, translational, and clinical knowledge on 3T1AM and its main metabolite 3-iodothyroacetic acid, focusing on endocrine-relevant aspects and open but highly challenging issues.
Collapse
Affiliation(s)
- Josef Köhrle
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Heike Biebermann
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| |
Collapse
|
4
|
Zhang Z, Boelen A, Kalsbeek A, Fliers E. TRH Neurons and Thyroid Hormone Coordinate the Hypothalamic Response to Cold. Eur Thyroid J 2018; 7:279-288. [PMID: 30574457 PMCID: PMC6276749 DOI: 10.1159/000493976] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 09/21/2018] [Indexed: 12/28/2022] Open
Abstract
Thyroid hormone (TH) plays a key role in regulating body temperature in mammals. Cold exposure stimulates the hypothalamus-pituitary-thyroid (HPT) axis at the hypothalamic level by activating hypophysiotropic thyrotropin-releasing hormone (TRH)-producing neurons, ultimately resulting in increased plasma TH concentrations. Importantly, the local TH metabolism within various cold-responsive organs enables tissue-specific action of TH on heat production and adaption to cold independently of the circulating TH levels. In addition to these neuroendocrine effects, TRH neurons in the hypothalamus also have neural connections with brown adipose tissue (BAT), probably contributing to regulation of thermogenesis by the autonomic nervous system. Recent studies have demonstrated that intrahypothalamic TH has profound metabolic effects on BAT, the liver, and the heart that are mediated via the autonomic nervous system. These effects originate in various hypothalamic nuclei, including the paraventricular nucleus (PVN), the ventromedial nucleus, and recently reported neurons in the anterior hypothalamic area, indicating a potential central function for TH on thermoregulation. Finally, although robust stimulation of the thermogenic program in BAT was shown upon TH administration in the ventromedial hypothalamus, the physiological relevance of these neurally mediated effects of TH is unclear at present. This review provides an overview of studies reporting the role of TH in cold defense, with a focus on recent literature evidencing the centrally mediated effects of TRH and TH.
Collapse
Affiliation(s)
- Zhi Zhang
- Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Anita Boelen
- Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- *Eric Fliers, Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, NL–1105AZ Amsterdam (The Netherlands), E-Mail
| |
Collapse
|
5
|
Zhang Z, Boelen A, Bisschop PH, Kalsbeek A, Fliers E. Hypothalamic effects of thyroid hormone. Mol Cell Endocrinol 2017; 458:143-148. [PMID: 28088468 DOI: 10.1016/j.mce.2017.01.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 11/30/2022]
Abstract
Thyroid hormone (TH) is a key driver of metabolism in mammals. Plasma concentrations of TH are kept within a narrow range by negative feedback regulation in the hypothalamus-pituitary-thyroid (HPT) axis. Plasma TH concentrations are an important determinant of metabolic processes in liver and brown adipose tissue (BAT). In addition to endocrine effects of TH derived from the circulation, recent studies have demonstrated additional neural routes for intrahypothalamic thyroid hormone to regulate metabolism in liver and BAT via the sympathetic and parasympathetic branch of the autonomic nervous system (ANS). This review provides an overview of studies reporting metabolic effects of selective administration of T3 within hypothalamic nuclei including the paraventricular nucleus (PVN), the ventromedial nucleus (VMH), the arcuate nucleus (Arc), and the anterior hypothalamic area (AHA). This overview of the literature suggests that intrahypothalamic T3 can have profound effects on hepatic glucose production and insulin sensitivity, energy expenditure in BAT, cardiovascular function and feeding behavior. As the experiments have been performed in experimental animals exclusively, and the timing and route of T3 administration may be an important determinant of effect size, the clinical relevance of these metabolic effects in the chronic setting remains to be established.
Collapse
Affiliation(s)
- Zhi Zhang
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Anita Boelen
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Peter H Bisschop
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, The Netherlands; Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, The Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, The Netherlands.
| |
Collapse
|
6
|
Gnocchi D, Steffensen KR, Bruscalupi G, Parini P. Emerging role of thyroid hormone metabolites. Acta Physiol (Oxf) 2016; 217:184-216. [PMID: 26748938 DOI: 10.1111/apha.12648] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 07/28/2015] [Accepted: 01/03/2016] [Indexed: 12/15/2022]
Abstract
Thyroid hormones (THs) are essential for the regulation of development and metabolism in key organs. THs produce biological effects both by directly affecting gene expression through the interaction with nuclear receptors (genomic effects) and by activating protein kinases and/or ion channels (short-term effects). Such activations can be either direct, in the case of ion channels, or mediated by membrane or cytoplasmic receptors. Short-term-activated signalling pathways often play a role in the regulation of genomic effects. Several TH intermediate metabolites, which were previously considered without biological activity, have now been associated with a broad range of actions, mostly attributable to short-term effects. Here, we give an overview of the physiological roles and mechanisms of action of THs, focusing on the emerging position that TH metabolites are acquiring as important regulators of physiology and metabolism.
Collapse
Affiliation(s)
- D. Gnocchi
- Division of Clinical Chemistry; Department of Laboratory Medicine; Karolinska Institutet at Karolinska University Hospital Huddinge; Stockholm Sweden
| | - K. R. Steffensen
- Division of Clinical Chemistry; Department of Laboratory Medicine; Karolinska Institutet at Karolinska University Hospital Huddinge; Stockholm Sweden
| | - G. Bruscalupi
- Department of Biology and Biotechnology ‘Charles Darwin’; Sapienza University of Rome; Rome Italy
| | - P. Parini
- Division of Clinical Chemistry; Department of Laboratory Medicine; Karolinska Institutet at Karolinska University Hospital Huddinge; Stockholm Sweden
- Metabolism Unit; Department of Medicine; Karolinska Institutet at Karolinska University Hospital Huddinge; Stockholm Sweden
| |
Collapse
|
7
|
Interactions of L-3,5,3'-Triiodothyronine [corrected], Allopregnanolone, and Ivermectin with the GABAA Receptor: Evidence for Overlapping Intersubunit Binding Modes. PLoS One 2015; 10:e0139072. [PMID: 26421724 PMCID: PMC4589331 DOI: 10.1371/journal.pone.0139072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/09/2015] [Indexed: 11/28/2022] Open
Abstract
Structural mechanisms of modulation of γ-aminobutyric acid (GABA) type A receptors by neurosteroids and hormones remain unclear. The thyroid hormone L-3,5,3’-triiodothyronine (T3) inhibits GABAA receptors at micromolar concentrations and has common features with neurosteroids such as allopregnanolone (ALLOP). Here we use functional experiments on α2β1γ2 GABAA receptors expressed in Xenopus oocytes to detect competitive interactions between T3 and an agonist (ivermectin, IVM) with a crystallographically determined binding site at subunit interfaces in the transmembrane domain of a homologous receptor (glutamate-gated chloride channel, GluCl). T3 and ALLOP also show competitive effects, supporting the presence of both a T3 and ALLOP binding site at one or more subunit interfaces. Molecular dynamics (MD) simulations over 200 ns are used to investigate the dynamics and energetics of T3 in the identified intersubunit sites. In these simulations, T3 molecules occupying all intersubunit sites (with the exception of the α-β interface) display numerous energetically favorable conformations with multiple hydrogen bonding partners, including previously implicated polar/acidic sidechains and a structurally conserved deformation in the M1 backbone.
Collapse
|
8
|
Zucchi R, Accorroni A, Chiellini G. Update on 3-iodothyronamine and its neurological and metabolic actions. Front Physiol 2014; 5:402. [PMID: 25360120 PMCID: PMC4199266 DOI: 10.3389/fphys.2014.00402] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/28/2014] [Indexed: 11/23/2022] Open
Abstract
3-iodothyronamine (T1AM) is an endogenous amine, that has been detected in many rodent tissues, and in human blood. It has been hypothesized to derive from thyroid hormone metabolism, but this hypothesis still requires validation. T1AM is not a ligand for nuclear thyroid hormone receptors, but stimulates with nanomolar affinity trace amine-associated receptor 1 (TAAR1), a G protein-coupled membrane receptor. With a lower affinity it interacts with alpha2A adrenergic receptors. Additional targets are represented by apolipoprotein B100, mitochondrial ATP synthase, and membrane monoamine transporters, but the functional relevance of these interactions is still uncertain. Among the effects reported after administration of exogenous T1AM to experimental animals, metabolic and neurological responses deserve special attention, because they were obtained at low dosages, which increased endogenous tissue concentration by about one order of magnitude. Systemic T1AM administration favored fatty acid over glucose catabolism, increased ketogenesis and increased blood glucose. Similar responses were elicited by intracerebral infusion, which inhibited insulin secretion and stimulated glucagon secretion. However, T1AM administration increased ketogenesis and gluconeogenesis also in hepatic cell lines and in perfused liver preparations, providing evidence for a peripheral action, as well. In the central nervous system, T1AM behaved as a neuromodulator, affecting adrenergic and/or histaminergic neurons. Intracerebral T1AM administration favored learning and memory, modulated sleep and feeding, and decreased the pain threshold. In conclusion T1AM should be considered as a component of thyroid hormone signaling and might play a significant physiological and/or pathophysiological role. T1AM analogs have already been synthetized and their therapeutical potential is currently under investigation. 3-iodothyronamine (T1AM) is a biogenic amine whose structure is closely related to that of thyroid hormone (3,5,3′-triiodothyronine, or T3). The differences with T3 are the absence of the carboxylate group and the substitution of iodine with hydrogen in 5 and 3′ positions (Figure 1). In this paper we will review the evidence supporting the hypothesis that T1AM is a chemical messenger, namely that it is an endogenous substance able to interact with specific receptors producing significant functional effects. Special emphasis will be placed on neurological and metabolic effects, which are likely to have physiological and pathophysiological importance.
Collapse
Affiliation(s)
- Riccardo Zucchi
- Laboratory of Biochemistry, Department of Pathology, University of Pisa Pisa, Italy
| | - Alice Accorroni
- Laboratory of Biochemistry, Department of Pathology, University of Pisa Pisa, Italy
| | - Grazia Chiellini
- Laboratory of Biochemistry, Department of Pathology, University of Pisa Pisa, Italy
| |
Collapse
|
9
|
James TD, Moffett SX, Scanlan TS, Martin JV. Effects of acute microinjections of the thyroid hormone derivative 3-iodothyronamine to the preoptic region of adult male rats on sleep, thermoregulation and motor activity. Horm Behav 2013; 64:81-8. [PMID: 23702093 PMCID: PMC4091812 DOI: 10.1016/j.yhbeh.2013.05.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 02/22/2013] [Accepted: 05/11/2013] [Indexed: 11/27/2022]
Abstract
The decarboxylated thyroid hormone derivative 3-iodothyronamine (T1AM) has been reported as having behavioral and physiological consequences distinct from those of thyroid hormones. Here, we investigate the effects of T1AM on EEG-defined sleep after acute administration to the preoptic region of adult male rats. Our laboratory recently demonstrated a decrease in EEG-defined sleep after administration of 3,3',5-triiodo-l-thyronine (T3) to the same brain region. After injection of T1AM or vehicle solution, EEG, EMG, activity, and core body temperature were recorded for 24h. Sleep parameters were determined from EEG and EMG data. Earlier investigations found contrasting systemic effects of T3 and T1AM, such as decreased heart rate and body temperature after intraperitoneal T1AM injection. However, nREM sleep was decreased in the present study after injections of 1 or 3 μg T1AM, but not after 0.3 or 10 μg, closely mimicking the previously reported effects of T3 administration to the preoptic region. The biphasic dose-response observed after either T1AM or T3 administration seems to indicate shared mechanisms and/or functions of sleep regulation in the preoptic region. Consistent with systemic administration of T1AM, however, microinjection of T1AM decreased body temperature. The current study is the first to show modulation of sleep by T1AM, and suggests that T1AM and T3 have both shared and independent effects in the adult mammalian brain.
Collapse
Affiliation(s)
- Thomas D. James
- Center for Computational and Integrative Biology, Rutgers University, 315 Penn Street, Camden, NJ 08102, USA
| | - Steven X. Moffett
- Center for Computational and Integrative Biology, Rutgers University, 315 Penn Street, Camden, NJ 08102, USA
| | - Thomas S. Scanlan
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Joseph V. Martin
- Center for Computational and Integrative Biology, Rutgers University, 315 Penn Street, Camden, NJ 08102, USA
- Corresponding author. Fax: +1 856 225 6312., (J.V. Martin)
| |
Collapse
|