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Matsumoto Y, Kowata N, Kikuyama S, Okada R. Analyses of mRNA Expression Levels of Pituitary Hormones, Their Hypothalamic Regulating Factors, and Receptors Involved in Metamorphosis with Special Reference to the Summer and Winter Seasons. Zoolog Sci 2024; 41:32-38. [PMID: 38587515 DOI: 10.2108/zs230080] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 12/01/2023] [Indexed: 04/09/2024]
Abstract
Bullfrog (Rana catesbeiana) larvae inhabiting the main island of Japan overwinter as preclimax animals, whereas the larvae that reached climax in summer complete metamorphosis. We analyzed the mRNA expression levels of the adenohypophyseal hormones, hypothalamic hormones, and their receptors that are involved in controlling metamorphosis in tadpoles at various developmental stages available in summer and winter in order to understand the hormonal mechanism regulating metamorphosis progression. Corticotropin-releasing factor (CRF) and thyrotropin β-subunit (TSHβ) mRNA expression was enhanced as they reached the climax stage in metamorphosing summer tadpoles, although type 2 CRF receptor (CRFR2) mRNA levels demonstrated a tendency of elevation, indicating the activation of the hypothalamo-hypophyseal axis for stimulating the release of thyroid hormone in summer. Arginine vasotocin (AVT) mRNA levels were elevated as metamorphosis progressed, but mRNA expression levels were not synchronized with those of proopiomelanocortin (POMC) and V1b-type AVT receptor (V1bR). The elevation of mRNA levels of prolactin (PRL) 1A and type 3 thyrotropin-releasing hormone receptor (TRHR3), but not of thyrotropin-releasing hormone (TRH) precursor mRNA levels, was noted in climactic tadpoles, indicating that PRL mRNA levels are not simply dependent on the expression levels of TRH precursor mRNA. In the preclimactic larvae captured in winter, which are in metamorphic stasis, mRNA levels of pituitary hormones, hypothalamic factors, and their receptors remained low or at levels similar to those of the larvae captured in summer. These results indicate the relationship between the mRNA expression of metamorphosis-related factors and the seasonal progression/stasis of metamorphosis.
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Affiliation(s)
- Yuki Matsumoto
- Department of Biological Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
| | - Natsuno Kowata
- Department of Biological Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
| | - Sakae Kikuyama
- Department of Biology, Faculty of Education and Integrated Sciences, Center for Advanced Biomedical Sciences, Waseda University, Tokyo 162-8480, Japan
| | - Reiko Okada
- Department of Biological Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan,
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Rousseau K, Dufour S, Sachs LM. Interdependence of Thyroid and Corticosteroid Signaling in Vertebrate Developmental Transitions. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.735487] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Post-embryonic acute developmental processes mainly allow the transition from one life stage in a specific ecological niche to the next life stage in a different ecological niche. Metamorphosis, an emblematic type of these post-embryonic developmental processes, has occurred repeatedly and independently in various phylogenetic groups throughout metazoan evolution, such as in cnidarian, insects, molluscs, tunicates, or vertebrates. This review will focus on metamorphoses and developmental transitions in vertebrates, including typical larval metamorphosis in anuran amphibians, larval and secondary metamorphoses in teleost fishes, egg hatching in sauropsids and birth in mammals. Two neuroendocrine axes, the hypothalamic-pituitary-thyroid and the hypothalamic-pituitary-adrenal/interrenal axes, are central players in the regulation of these life transitions. The review will address the molecular and functional evolution of these axes and their interactions. Mechanisms of integration of internal and environmental cues, and activation of these neuroendocrine axes represent key questions in an “eco-evo-devo” perspective of metamorphosis. The roles played by developmental transitions in the innovation, adaptation, and plasticity of life cycles throughout vertebrates will be discussed. In the current context of global climate change and habitat destruction, the review will also address the impact of environmental factors, such as global warming and endocrine disruptors on hypothalamic-pituitary-thyroid and hypothalamic-pituitary-adrenal/interrenal axes, and regulation of developmental transitions.
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Lazcano I, Rodríguez Rodríguez A, Uribe RM, Orozco A, Joseph-Bravo P, Charli JL. Evolution of thyrotropin-releasing factor extracellular communication units. Gen Comp Endocrinol 2021; 305:113642. [PMID: 33039406 DOI: 10.1016/j.ygcen.2020.113642] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 09/12/2020] [Accepted: 09/28/2020] [Indexed: 12/16/2022]
Abstract
Thyroid hormones (THs) are ancient signaling molecules that contribute to the regulation of metabolism, energy homeostasis and growth. In vertebrates, the hypothalamus-pituitary-thyroid (HPT) axis links the corresponding organs through hormonal signals, including thyrotropin releasing factor (TRF), and thyroid stimulating hormone (TSH) that ultimately activates the synthesis and secretion of THs from the thyroid gland. Although this axis is conserved among most vertebrates, the identity of the hypothalamic TRF that positively regulates TSH synthesis and secretion varies. We review the evolution of the hypothalamic factors that induce TSH secretion, including thyrotropin-releasing hormone (TRH), corticotrophin-releasing hormone (CRH), urotensin-1-3, and sauvagine, and non-mammalian glucagon-like peptide in metazoans. Each of these peptides is part of an extracellular communication unit likely composed of at least 3 elements: the peptide, G-protein coupled receptor and bioavailability regulator, set up on the central neuroendocrine articulation. The bioavailability regulators include a TRH-specific ecto-peptidase, pyroglutamyl peptidase II, and a CRH-binding protein, that together with peptide secretion/transport rate and transduction coupling and efficiency at receptor level shape TRF signal intensity and duration. These vertebrate TRF communication units were coopted from bilaterian ancestors. The bona fide elements appeared early in chordates, and are either used alternatively, in parallel, or sequentially, in different vertebrate classes to control centrally the activity of the HPT axis. Available data also suggest coincidence between apparition of ligand and bioavailability regulator.
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Affiliation(s)
- Iván Lazcano
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, Mexico
| | - Adair Rodríguez Rodríguez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Rosa María Uribe
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Aurea Orozco
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, Mexico
| | - Patricia Joseph-Bravo
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Jean-Louis Charli
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico.
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Li X, Li Z, Deng Y, Zhang J, Li J, Wang Y. Characterization of a novel thyrotropin-releasing hormone receptor, TRHR3, in chickens. Poult Sci 2019; 99:1643-1654. [PMID: 32115036 PMCID: PMC7587745 DOI: 10.1016/j.psj.2019.10.062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 10/18/2019] [Accepted: 10/22/2019] [Indexed: 11/06/2022] Open
Abstract
The physiological roles of thyrotropin-releasing hormone (TRH) are proposed to be mediated by TRH receptors (TRHR), which have been divided into 3 subtypes, namely, TRHR1, TRHR2, and TRHR3, in vertebrates. Although 2 TRH receptors (TRHR1 and TRHR3) have been predicted to exist in birds, it remains unclear whether TRHR3 is a functional TRH receptor similar to TRHR1. Here, we reported the functionality and tissue expression of TRHR3 in chickens. The cloned chicken TRHR3 (cTRHR3) encodes a receptor of 387 amino acids, which shares high-amino-acid identities (63–80%) to TRHR3 of parrots, lizards, Xenopus tropicalis, and tilapia and comparatively lower sequence identities to chicken TRHR1 or mouse TRHR2. Using cell-based luciferase reporter assays and Western blot, we demonstrated that similar to chicken TRHR1 (cTRHR1), cTRHR3 expressed in HEK 293 cells can be potently activated by TRH and that its activation stimulates multiple signaling pathways, indicating both TRH receptors are functional. Quantitative real-time PCR revealed that cTRHR1 and cTRHR3 are widely, but differentially, expressed in chicken tissues, and their expression is likely controlled by promoters located upstream of exon 1, which display strong promoter activities in cultured DF-1 cells. cTRHR1 is highly expressed in the anterior pituitary and testes, while cTRHR3 is highly expressed in the muscle, testes, fat, pituitary, spinal cord, and many brain regions (including hypothalamus). These findings indicate that TRH actions are likely mediated by 2 TRH receptors in chickens. In conclusion, our data provide the first piece of evidence that both cTRHR3 and cTRHR1 are functional TRH receptors, which helps to elucidate the physiological roles of TRH in birds.
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Affiliation(s)
- Xiaoxiao Li
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Zhengyang Li
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Yue Deng
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Jiannan Zhang
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Juan Li
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China.
| | - Yajun Wang
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China.
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Nakano M, Hasunuma I, Minagawa A, Iwamuro S, Yamamoto K, Kikuyama S, Machida T, Kobayashi T. Possible involvement of thyrotropin-releasing hormone receptor 3 in the release of prolactin in the metamorphosing bullfrog larvae. Gen Comp Endocrinol 2018; 267:36-44. [PMID: 29864416 DOI: 10.1016/j.ygcen.2018.05.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/30/2018] [Accepted: 05/25/2018] [Indexed: 01/09/2023]
Abstract
In amphibians, thyrotropin (TSH), corticotropin (ACTH) and prolactin (PRL) are regarded as the major pituitary hormones involved in metamorphosis, their releasing factors being corticotropin-releasing factor (CRF), arginine vasotocin (AVT), and thyrotropin-releasing hormone (TRH), respectively. It is also known that thyrotropes and corticotropes are equipped with CRF type-2 receptor and AVT V1b receptor, respectively. As for PRL cells, information about the type of receptor for TRH (TRHR) through which the action of TRH is mediated to induce the release of PRL is lacking. In order to fill this gap, an attempt was made to characterize the TRHR subtype existing in the PRL cells of the anterior pituitary gland of the bullfrog, Rana catesbeiana. We cloned cDNAs for three types of bullfrog TRHRs, namely TRHR1, TRHR2 and TRHR3, and confirmed that all of them are functional receptors for TRH by means of reporter gene assay. Analyses with semi-quantitative reverse transcription-PCR and in situ hybridization revealed that TRHR3 mRNA is expressed in the anterior lobe and that the signals reside mostly in the PRL cells. It was also noted that the expression levels of TRHR3 mRNA in the anterior pituitary as well as in the PRL cells of metamorphosing tadpoles elevate as metamorphosis progresses. Since the pattern of changes in TRHR3 mRNA levels in the larval pituitary is almost similar to that previously observed in the pituitary PRL mRNA and plasma PRL levels, we provide a view that TRHR3 mediates the action of TRH on the PRL cells to induce the release of PRL that is prerequisite for growth and metamorphosis in amphibians.
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Affiliation(s)
- Masaki Nakano
- Department of Biology, Faculty of Science, Toho University, Chiba 274-8510, Japan; Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Itaru Hasunuma
- Department of Biology, Faculty of Science, Toho University, Chiba 274-8510, Japan
| | - Atsuko Minagawa
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Shawichi Iwamuro
- Department of Biology, Faculty of Science, Toho University, Chiba 274-8510, Japan
| | - Kazutoshi Yamamoto
- Department of Biology, Faculty of Education and Integrated Sciences, Center for Advanced Biomedical Sciences, Waseda University, Tokyo 162-8480, Japan
| | - Sakae Kikuyama
- Department of Biology, Faculty of Education and Integrated Sciences, Center for Advanced Biomedical Sciences, Waseda University, Tokyo 162-8480, Japan
| | - Takeo Machida
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Tetsuya Kobayashi
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan.
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First-in-class thyrotropin-releasing hormone (TRH)-based compound binds to a pharmacologically distinct TRH receptor subtype in human brain and is effective in neurodegenerative models. Neuropharmacology 2014; 89:193-203. [PMID: 25281210 DOI: 10.1016/j.neuropharm.2014.09.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/26/2014] [Accepted: 09/18/2014] [Indexed: 12/13/2022]
Abstract
JAK4D, a first-in-class thyrotropin-releasing hormone (TRH)-based compound, is a prospective therapeutic candidate offering a multifaceted approach to treating neurodegeneration and other CNS conditions. The purpose of these studies was to determine the ability of JAK4D to bind to TRH receptors in human brain and to evaluate its neuropharmacological effects in neurodegenerative animal models. Additionally, JAK4D brain permeation was examined in mouse, and initial toxicology was assessed in vivo and in vitro. We report that JAK4D bound selectively with nanomolar affinity to native TRH receptors in human hippocampal tissue and showed for the first time that these receptors are pharmacologically distinct from TRH receptors in human pituitary, thus revealing a new TRH receptor subtype which represents a promising neurotherapeutic target in human brain. Systemic administration of JAK4D elicited statistically significant and clinically-relevant neuroprotective effects in three established neurodegenerative animal models: JAK4D reduced cognitive deficits when administered post-insult in a kainate (KA)-induced rat model of neurodegeneration; it protected against free radical release and neuronal damage evoked by intrastriatal microdialysis of KA in rat; and it reduced motor decline, weight loss, and lumbar spinal cord neuronal loss in G93A-SOD1 transgenic Amyotrophic Lateral Sclerosis mice. Ability to cross the blood-brain barrier and a clean initial toxicology profile were also shown. In light of these findings, JAK4D is an important tool for investigating the hitherto-unidentified central TRH receptor subtype reported herein and an attractive therapeutic candidate for neurodegenerative disorders.
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Meier NT, Haslam IS, Pattwell DM, Zhang GY, Emelianov V, Paredes R, Debus S, Augustin M, Funk W, Amaya E, Kloepper JE, Hardman MJ, Paus R. Thyrotropin-releasing hormone (TRH) promotes wound re-epithelialisation in frog and human skin. PLoS One 2013; 8:e73596. [PMID: 24023889 PMCID: PMC3759422 DOI: 10.1371/journal.pone.0073596] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 07/29/2013] [Indexed: 01/09/2023] Open
Abstract
There remains a critical need for new therapeutics that promote wound healing in patients suffering from chronic skin wounds. This is, in part, due to a shortage of simple, physiologically and clinically relevant test systems for investigating candidate agents. The skin of amphibians possesses a remarkable regenerative capacity, which remains insufficiently explored for clinical purposes. Combining comparative biology with a translational medicine approach, we report the development and application of a simple ex vivo frog (Xenopus tropicalis) skin organ culture system that permits exploration of the effects of amphibian skin-derived agents on re-epithelialisation in both frog and human skin. Using this amphibian model, we identify thyrotropin-releasing hormone (TRH) as a novel stimulant of epidermal regeneration. Moving to a complementary human ex vivo wounded skin assay, we demonstrate that the effects of TRH are conserved across the amphibian-mammalian divide: TRH stimulates wound closure and formation of neo-epidermis in organ-cultured human skin, accompanied by increased keratinocyte proliferation and wound healing-associated differentiation (cytokeratin 6 expression). Thus, TRH represents a novel, clinically relevant neuroendocrine wound repair promoter that deserves further exploration. These complementary frog and human skin ex vivo assays encourage a comparative biology approach in future wound healing research so as to facilitate the rapid identification and preclinical testing of novel, evolutionarily conserved, and clinically relevant wound healing promoters.
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Affiliation(s)
- Natalia T. Meier
- Department of Dermatology, University of Luebeck, Luebeck, Germany
- Department of Pathology, University of Luebeck, Luebeck, Germany
| | - Iain S. Haslam
- The Dermatology Centre, Salford Royal NHS Foundation Trust and Institute of Inflammation and Repair, School of Translational Medicine, University of Manchester, Manchester, United Kingdom
- * E-mail:
| | - David M. Pattwell
- The Dermatology Centre, Salford Royal NHS Foundation Trust and Institute of Inflammation and Repair, School of Translational Medicine, University of Manchester, Manchester, United Kingdom
| | - Guo-You Zhang
- Department of Dermatology, University of Luebeck, Luebeck, Germany
- Department of Hand and Plastic Surgery, the Second Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang Province, China
| | | | - Roberto Paredes
- The Healing Foundation Centre, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Sebastian Debus
- Department of Vascular Surgery, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Matthias Augustin
- Center for Dermatological Research, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | | | - Enrique Amaya
- The Healing Foundation Centre, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | | | - Matthew J. Hardman
- The Healing Foundation Centre, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Ralf Paus
- Department of Dermatology, University of Luebeck, Luebeck, Germany
- The Dermatology Centre, Salford Royal NHS Foundation Trust and Institute of Inflammation and Repair, School of Translational Medicine, University of Manchester, Manchester, United Kingdom
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Saito Y, Mekuchi M, Kobayashi N, Kimura M, Aoki Y, Masuda T, Azuma T, Fukami M, Iigo M, Yanagisawa T. Molecular cloning, molecular evolution and gene expression of cDNAs encoding thyrotropin-releasing hormone receptor subtypes in a teleost, the sockeye salmon (Oncorhynchus nerka). Gen Comp Endocrinol 2011; 174:80-8. [PMID: 21827760 DOI: 10.1016/j.ygcen.2011.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 06/22/2011] [Accepted: 07/25/2011] [Indexed: 12/21/2022]
Abstract
Molecular cloning of thyrotropin-releasing hormone receptors (TRHR) was performed in a teleost, the sockeye salmon (Oncorhynchus nerka). Four different TRHR cDNAs were cloned and named TRHR1, TRHR2a, TRHR2b and TRHR3 based on their similarity to known TRHR subtypes in vertebrates. Important residues for TRH binding were conserved in deduced amino acid sequences of the three TRHR subtypes except for the TRHR2b. Seven transmembrane domains were predicted for TRHR1, TRHR2a and TRHR3 proteins but only five for TRHR2b which appears to be truncated. In silico database analysis identified putative TRHR sequences including invertebrate TRHR and reptilian, avian and mammalian TRHR3. Phylogenetic analyses predicted the molecular evolution of TRHR in vertebrates: from the common ancestral TRHR (i.e. invertebrate TRHR), the TRHR2 subtype diverged first and then TRHR1 and TRHR3 diverged. Reverse transcription-polymerase chain reaction analyses revealed TRHR1 transcripts in the brain (hypothalamus), retina, pituitary gland and large intestine; TRHR2a in the brain (telencephalon and hypothalamus); and TRHR3 in the brain (olfactory bulbs) and retina.
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Affiliation(s)
- Yuichi Saito
- Department of Biotechnology, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
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Monga V, Meena CL, Rajput S, Pawar C, Sharma SS, Lu X, Gershengorn MC, Jain R. Synthesis, receptor binding, and CNS pharmacological studies of new thyrotropin-releasing hormone (TRH) analogues. ChemMedChem 2011; 6:531-43. [PMID: 21302359 DOI: 10.1002/cmdc.201000481] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/06/2011] [Indexed: 02/03/2023]
Abstract
As part of our search for selective and CNS-active thyrotropin-releasing hormone (TRH) analogues, we synthesized a set of 44 new analogues in which His and pGlu residues were modified or replaced. The analogues were evaluated as agonists at TRH-R1 and TRH-R2 in cells in vitro, and in vivo in mice for analeptic and anticonvulsant activities. Several analogues bound to TRH-R1 and TRH-R2 with good to moderate affinities, and are full agonists at both receptor subtypes. Specifically, analogue 21 a (R=CH3) exhibited binding affinities (Ki values) of 0.17 μM for TRH-R1 and 0.016 μM for TRH-R2; it is 10-fold less potent than TRH in binding to TRH-R1 and equipotent with TRH in binding to TRH-R2. Compound 21 a, the most selective agonist, activated TRH-R2 with a potency (EC50 value) of 0.0021 μM, but activated TRH-R1 at EC50=0.05 μM, and exhibited 24-fold selectivity for TRH-R2 over TRH-R1. The newly synthesized TRH analogues were also evaluated in vivo to assess their potencies in antagonism of barbiturate-induced sleeping time, and several analogues displayed potent analeptic activity. Specifically, analogues 21 a,b and 22 a,b decreased sleeping time by nearly 50% more than TRH. These analogues also displayed potent anticonvulsant activity and provided significant protection against PTZ-induced seizures, but failed to provide any protection in MES-induced seizures at 10 μmol kg(-1). The results of this study provide evidence that TRH analogues that show selectivity for TRH-R2 over TRH-R1 possess potent CNS activity.
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Affiliation(s)
- Vikramdeep Monga
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, Punjab 160 062, India
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Jenks BG, Galas L, Kuribara M, Desrues L, Kidane AH, Vaudry H, Scheenen WJJM, Roubos EW, Tonon MC. Analysis of the melanotrope cell neuroendocrine interface in two amphibian species, Rana ridibunda and Xenopus laevis: a celebration of 35 years of collaborative research. Gen Comp Endocrinol 2011; 170:57-67. [PMID: 20888821 DOI: 10.1016/j.ygcen.2010.09.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 09/17/2010] [Accepted: 09/27/2010] [Indexed: 01/19/2023]
Abstract
This review gives an overview of the functioning of the hypothalamo-hypophyseal neuroendocrine interface in the pituitary neurointermediate lobe, as it relates to melanotrope cell function in two amphibian species, Rana ridibunda and Xenopus laevis. It primarily but not exclusively concerns the work of two collaborating laboratories, the Laboratory for Molecular and Cellular Neuroendocrinology (University of Rouen, France) and the Department of Cellular Animal Physiology (Radboud University Nijmegen, The Netherlands). In the course of this review it will become apparent that Rana and Xenopus have, for the most part, developed the same or similar strategies to regulate the release of α-melanophore-stimulating hormone (α-MSH). The review concludes by highlighting the molecular and cellular mechanisms utilized by thyrotropin-releasing hormone (TRH) to activate Rana melanotrope cells and the function of autocrine brain-derived neurotrophic factor (BDNF) in the regulation of Xenopus melanotrope cell function.
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Affiliation(s)
- Bruce G Jenks
- Department of Cellular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands.
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Abstract
SummaryThe physiological role of thyreoliberin (TRH) is the preservation of homeostasis within four systems (i) the hypothalamic-hypophsysiotropic neuroendocrine system, (ii) the brain stem/midbrain/spinal cord system, (iii) the limbic/cortical system, and (iv) the chronobiological system. Thus TRH, via various cellular mechanisms, regulates a wide range of biological processes (arousal, sleep, learning, locomotive activity, mood) and possesses the potential for unique and widespread applications for treatment of human illnesses. Since the therapeutic potential of TRH is limited by its pharmacological profile (enzymatic instability, short half-life, undesirable effects), several synthetic analogues of TRH were constructed and studied in mono- or adjunct therapy of central nervous system (CNS) disturbances. The present article summarizes the current state of understanding of the physiological role of TRH and describes its putative role in clinical indications in CNS maladies with a focus on the action of TRH analogues.
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Galas L, Raoult E, Tonon MC, Okada R, Jenks BG, Castaño JP, Kikuyama S, Malagon M, Roubos EW, Vaudry H. TRH acts as a multifunctional hypophysiotropic factor in vertebrates. Gen Comp Endocrinol 2009; 164:40-50. [PMID: 19435597 DOI: 10.1016/j.ygcen.2009.05.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 04/28/2009] [Accepted: 05/05/2009] [Indexed: 11/17/2022]
Abstract
Thyrotropin-releasing hormone (TRH) is the first hypothalamic hypophysiotropic neuropeptide whose sequence has been chemically characterized. The primary structure of TRH (pGlu-His-Pro-NH(2)) has been fully conserved across the vertebrate phylum. TRH is generated from a large precursor protein that contains multiple repeats of the TRH progenitor tetrapeptide Gln-His-Pro-Gly. In all tetrapods, TRH-expressing neurons located in the hypothalamus project towards the external zone of the median eminence while in teleosts they directly innervate the pars distalis of the pituitary. In addition, in frogs and teleosts, a bundle of TRH-containing fibers terminate in the neurointermediate lobe of the pituitary gland. Although TRH was originally named for its ability to trigger the release of thyroid-stimulating hormone (TSH) in mammals, it later became apparent that it exerts multiple, species-dependent hypophysiotropic activities. Thus, in fish TRH stimulates growth hormone (GH) and prolactin (PRL) release but does not affect TSH secretion. In amphibians, TRH is a marginal stimulator of TSH release in adult frogs, not in tadpoles, and a major releasing factor for GH and PRL. In birds, TRH triggers TSH and GH secretion. In mammals, TRH stimulates TSH, GH and PRL release. In fish and amphibians, TRH is also a very potent stimulator of alpha-melanocyte-stimulating hormone release. Because the intermediate lobe of the pituitary of amphibians is composed by a single type of hormone-producing cells, the melanotrope cells, it is a suitable model in which to investigate the mechanism of action of TRH at the cellular and molecular level. The occurrence of large amounts of TRH in the frog skin and high concentrations of TRH in frog plasma suggests that, in amphibians, skin-derived TRH may exert hypophysiotropic functions.
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Affiliation(s)
- Ludovic Galas
- Regional Platform for Cell Imaging (PRIMACEN), European Institute for Peptide Research (IFRMP 23), University of Rouen, Mont-Saint-Aignan, France
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13
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Abbassi F, Oury B, Blasco T, Sereno D, Bolbach G, Nicolas P, Hani K, Amiche M, Ladram A. Isolation, characterization and molecular cloning of new temporins from the skin of the North African ranid Pelophylax saharica. Peptides 2008; 29:1526-33. [PMID: 18584916 DOI: 10.1016/j.peptides.2008.05.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2008] [Revised: 05/02/2008] [Accepted: 05/07/2008] [Indexed: 10/22/2022]
Abstract
Temporins are small antimicrobial peptides isolated from North American and Eurasian ranid frogs that are particularly active against Gram-positive bacteria. To date, no temporins have been characterized from North African frog species. We isolated three novel members of the temporin family, named temporin-1Sa (FLSGIVGMLGKLF(amide)), -1Sb (FLPIVTNLLSGLL(amide)), and -1Sc (FLSHIAGFLSNLF(amide)), from the skin of the Sahara frog Pelophylax (Rana) saharica originating from Tunisia. These temporins were identified by a combined mass spectrometry/molecular cloning approach. Temporin-1Sa was found to be highly active against Gram-positive and Gram-negative bacteria, yeasts and fungi (MIC=2-30 microM). To our knowledge, this is the first 13-residue member of the temporin family with a net charge of +2 that shows such broad-spectrum activity with particularly high potency on the clinically relevant Gram-negative strains, Escherichia coli (MIC=10 microM) and Pseudomonas aeruginosa (MIC=31 microM). Moreover, temporin-1Sa displays significant antiparasitic activity (IC50 approximately 20 microM) against the promastigote and amastigote stages of Leishmania infantum.
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Affiliation(s)
- Feten Abbassi
- FRE 2852, Peptidome de la Peau des Amphibiens, Université Pierre et Marie Curie/CNRS, Tour 43, 2 place Jussieu, 75251 Paris Cedex 05, France
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14
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Hogan N, O'Boyle KM, Hinkle PM, Kelly JA. A novel TRH analog, Glp-Asn-Pro-D-Tyr-D-TrpNH2, binds to [3H][3-Me-His2]TRH-labelled sites in rat hippocampus and cortex but not pituitary or heterologous cells expressing TRHR1 or TRHR2. Neurosci Lett 2007; 431:26-30. [PMID: 18069127 DOI: 10.1016/j.neulet.2007.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 11/01/2007] [Accepted: 11/07/2007] [Indexed: 11/28/2022]
Abstract
Glp-Asn-Pro-D-Tyr-D-TrpNH(2) is a novel synthetic peptide that mimics and amplifies central actions of thyrotropin-releasing hormone (TRH) in rat without releasing TSH. The aim of this study was to compare the binding properties of this pentapeptide and its all-L counterpart (Glp-Asn-Pro-Tyr-TrpNH(2)) to TRH receptors in native rat brain tissue and cells expressing the two TRH receptor subtypes identified in rat to date, namely TRHR1 and TRHR2. Radioligand binding studies were carried out using [(3)H][3-Me-His(2)]TRH to label receptors in hippocampal, cortical and pituitary tissue, GH4 pituitary cells, as well as CHO cells expressing TRHR1 and/or TRHR2. In situ hybridization studies suggest that cortex expresses primarily TRHR2 mRNA, hippocampus primarily TRHR1 mRNA and pituitary exclusively TRHR1 mRNA. Competition experiments showed [3-Me-His(2)]TRH potently displaced [(3)H][3-Me-His(2)]TRH binding from all tissues/cells investigated. Glp-Asn-Pro-D-Tyr-D-TrpNH(2) in concentrations up to 10(-5)M did not displace [(3)H][3-Me-His(2)]TRH binding to membranes derived from GH4 cells or CHO-TRHR1 cells, consistent with its lack of binding to pituitary membranes and TSH-releasing activity. Similar results were obtained for the corresponding all-L peptide. In contrast, both pentapeptides displaced binding from rat hippocampal membranes (pIC(50) Glp-Asn-Pro-D-Tyr-D-TrpNH(2): 7.7+/-0.2; pIC(50) Glp-Asn-Pro-Tyr-TrpNH(2): 6.6+/-0.2), analogous to cortical membranes (pIC(50) Glp-Asn-Pro-D-Tyr-D-TrpNH(2): 7.8+/-0.2; pIC(50) Glp-Asn-Pro-Tyr-TrpNH(2): 6.6+/-0.2). Neither peptide, however, displaced [(3)H][3-Me-His(2)]TRH binding to CHO-TRHR2. Thus, this study reveals for the first time significant differences in the binding properties of native and heterologously expressed TRH receptors. Also, the results raise the possibility that Glp-Asn-Pro-D-Tyr-D-TrpNH(2) is not displacing [(3)H][3-Me-His(2)]TRH from a known TRH receptor in rat cortex, but rather a hitherto unidentified TRH receptor.
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Affiliation(s)
- Nicola Hogan
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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15
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Scalabrino GA, Hogan N, O'Boyle KM, Slator GR, Gregg DJ, Fitchett CM, Draper SM, Bennett GW, Hinkle PM, Bauer K, Williams CH, Tipton KF, Kelly JA. Discovery of a dual action first-in-class peptide that mimics and enhances CNS-mediated actions of thyrotropin-releasing hormone. Neuropharmacology 2007; 52:1472-81. [PMID: 17418282 DOI: 10.1016/j.neuropharm.2007.02.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 02/07/2007] [Accepted: 02/09/2007] [Indexed: 10/23/2022]
Abstract
Thyrotropin-releasing hormone (TRH) displays multiple CNS-mediated actions that have long been recognized to have therapeutic potential in treating a wide range of neurological disorders. Investigations of CNS functions and clinical use of TRH are hindered, however, due to its rapid degradation by TRH-degrading ectoenzyme (TRH-DE). We now report the discovery of a set of first-in-class compounds that display unique ability to both potently inhibit TRH-DE and bind to central TRH receptors with unparalleled affinity. This dual pharmacological activity within one molecular entity was found through selective manipulation of peptide stereochemistry. Notably, the lead compound of this set, L-pyroglutamyl-L-asparaginyl-L-prolyl-D-tyrosyl-D-tryptophan amide (Glp-Asn-Pro-D-Tyr-D-TrpNH(2)), is effective in vivo at producing and potentiating central actions of TRH without evoking release of thyroid-stimulating hormone (TSH). Specifically, this peptide displayed high plasma stability and combined potent inhibition of TRH-DE (K(i) 151 nM) with high affinity binding to central TRH receptors (K(i) 6.8 nM). Moreover, intraperitoneal injection of this peptide mimicked and augmented the effects of TRH on behavioural activity in rat. Analogous to TRH, it also antagonized pentobarbital-induced narcosis when administered intravenously. This discovery provides new opportunities for probing the role of TRH actions in the CNS and a basis for development of novel TRH-based neurotherapeutics.
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Affiliation(s)
- Gaia A Scalabrino
- School of Biochemistry and Immunology and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
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Jenks BG, Kidane AH, Scheenen WJJM, Roubos EW. Plasticity in the melanotrope neuroendocrine interface of Xenopus laevis. Neuroendocrinology 2007; 85:177-85. [PMID: 17389778 DOI: 10.1159/000101434] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Accepted: 02/22/2007] [Indexed: 11/19/2022]
Abstract
Melanotrope cells of the amphibian pituitary pars intermedia produce alpha-melanophore-stimulating hormone (alpha-MSH), a peptide which causes skin darkening during adaptation to a dark background. The secretory activity of the melanotrope of the South African clawed toad Xenopus laevis is regulated by multiple factors, both classical neurotransmitters and neuropeptides from the brain. This review concerns the plasticity displayed in this intermediate lobe neuroendocrine interface during physiological adaptation to the environment. The plasticity includes dramatic morphological plasticity in both pre- and post-synaptic elements of the interface. Inhibitory neurons in the suprachiasmatic nucleus, designated suprachiasmatic melanotrope-inhibiting neurons (SMINs), possess more and larger synapses on the melanotrope cells in white than in black-background adapted animals; in the latter animals the melanotropes are larger and produce more proopiomelanocortin (POMC), the precursor of alpha-MSH. On a white background, pre-synaptic SMIN plasticity is reflected by a higher expression of inhibitory neuropeptide Y (NPY) and is closely associated with postsynaptic melanotrope plasticity, namely a higher expression of the NPY Y1 receptor. Interestingly, melanotrope cells in such animals also display higher expression of the receptors for thyrotropin-releasing hormone (TRH) and urocortin 1, two neuropeptides that stimulate alpha-MSH secretion. Possibly, in white-adapted animals melanotropes are sensitized to neuropeptide stimulation so that, when the toad moves to a black background, they can immediately initiate alpha-MSH secretion to achieve rapid adaptation to the new background condition. The melanotrope cell also produces brain-derived neurotrophic factor (BDNF), which is co-sequestered with alpha-MSH in secretory granules within the cells. The neurotrophin seems to control melanotrope cell plasticity in an autocrine way and we speculate that it may also control presynaptic SMIN plasticity.
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Affiliation(s)
- Bruce G Jenks
- Department of Cellular Animal Physiology, Radboud University Nijmegen, Nijmegen, The Netherlands.
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Galas L, Bidaud I, Bulant M, Jenks BG, Ouwens DTWM, Jégou S, Ladram A, Roubos EW, Nicolas P, Tonon MC, Vaudry H. In situ hybridization localization of TRH precursor and TRH receptor mRNAs in the brain and pituitary of Xenopus laevis. Ann N Y Acad Sci 2006; 1040:95-105. [PMID: 15891012 DOI: 10.1196/annals.1327.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We examined the distribution of the mRNAs encoding proTRH and the three TRH receptor subtypes (xTRHR1, xTRHR2, and xTRHR3) in the Xenopus laevis CNS and pituitary. A positive correlation was generally observed between the expression patterns of proTRH and xTRHR mRNAs. xTRHRs were widely expressed in the telencephalon and diencephalon, where two or even three xTRHR mRNAs were often simultaneously observed within the same brain structures. In the pituitary, xTRHR2 was selectively expressed in the distal lobe, and xTRHR3 was found exclusively in the intermediate lobe of white background-adapted animals, indicating that, in amphibians, the effect of TRH on alpha-melanotropin (alpha-MSH) secretion from melanotrope cells is mediated through the novel receptor subtype xTRHR3.
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Affiliation(s)
- L Galas
- European Institute for Peptide Research (IFRMP 23), Laboratory of Cellular and Molecular Neuroendocrinology, INSERM U413, UA CNRS, University of Rouen, Mont-Saint-Aignan, France
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Bidaud I, Galas L, Bulant M, Jenks BG, Ouwens DTWM, Jégou S, Ladram A, Roubos EW, Tonon MC, Nicolas P, Vaudry H. Distribution of the mRNAs encoding the thyrotropin-releasing hormone (TRH) precursor and three TRH receptors in the brain and pituitary of Xenopus laevis: effect of background color adaptation on TRH and TRH receptor gene expression. J Comp Neurol 2004; 477:11-28. [PMID: 15281077 DOI: 10.1002/cne.20235] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In amphibians, thyrotropin-releasing hormone (TRH) is a potent stimulator of alpha-melanotropin (alpha-MSH) secretion, so TRH plays a major role in the neuroendocrine regulation of skin-color adaptation. We have recently cloned a third type of TRH receptor in Xenopus laevis (xTRHR3) that has not yet been characterized in any other vertebrate species. In the present study, we have examined the distribution of the mRNAs encoding proTRH and the three receptor subtypes (xTRHR1, xTRHR2, and xTRHR3) in the frog CNS and pituitary, and we have investigated the effect of background color adaptation on the expression of these mRNAs. A good correlation was generally observed between the expression patterns of proTRH and xTRHR mRNAs. xTRHRs, including the novel receptor subtype xTRHR3, were widely expressed in the telencephalon and diencephalon, where two or even three xTRHR mRNAs were often simultaneously observed within the same brain structures. In the pituitary, xTRHR2 was expressed selectively in the distal lobe, and xTRHR3 was found exclusively in the intermediate lobe. Adaptation of frog skin to background illumination had no effect on the expression of proTRH and xTRHRs in the brain. In contrast, adaptation of the animals to a white background provoked an 18-fold increase in xTRHR3 mRNA concentration in the intermediate lobe of the pituitary. These data demonstrate that, in amphibians, the effect of TRH on alpha-MSH secretion is mediated through the novel receptor subtype xTRHR3.
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Affiliation(s)
- Isabelle Bidaud
- Institute Jacques Monod, Laboratory of Bioactivation of Peptides, Centre National de la Recherche Scientifique, University of Paris 6-7, UMR 7592, 75251 Paris, France
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Gary KA, Sevarino KA, Yarbrough GG, Prange AJ, Winokur A. The thyrotropin-releasing hormone (TRH) hypothesis of homeostatic regulation: implications for TRH-based therapeutics. J Pharmacol Exp Ther 2003; 305:410-6. [PMID: 12606661 DOI: 10.1124/jpet.102.044040] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The functions of thyrotropin-releasing hormone (TRH) in the central nervous system (CNS) can be conceptualized as performed by four anatomically distinct components that together comprise a general TRH homeostatic system. These components are 1) the hypothalamic-hypophysiotropic neuroendocrine system, 2) the brainstem/midbrain/spinal cord system, 3) the limbic/cortical system, and 4) the chronobiological system. We propose that the main neurobiological function of TRH is to promote homeostasis, accomplished through neuronal mechanisms resident in these four integrated systems. This hypothesis offers a unifying basis for understanding the myriad actions of TRH and TRH-related drugs already demonstrated in animals and humans. It is consistent with the traditional role of TRH as a regulator of metabolic homeostasis. An appreciation of the global function of TRH to modulate and normalize CNS activity, along with an appreciation of the inherent limitations of TRH itself as a therapeutic agent, leads to rational expectations of therapeutic benefit from metabolically stable TRH-mimetic drugs in a remarkably broad spectrum of clinical situations, both as monotherapy and as an adjunct to other therapeutic agents. The actions of TRH are numerous and varied. This has been viewed in the past as a conceptual and practical impediment to the development of TRH analogs. Herein, we alternatively propose that these manifold actions should be considered as a rational and positive impetus to the development of TRH-based drugs with the potential for unique and widespread applicability in human illness.
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Affiliation(s)
- Keith A Gary
- Department of Psychiatry, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 06030-6415, USA
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