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Prokai-Tatrai K, Nguyen V, Prokai L. [β-Glu 2]TRH Is a Functional Antagonist of Thyrotropin-Releasing Hormone (TRH) in the Rodent Brain. Int J Mol Sci 2021; 22:ijms22126230. [PMID: 34207724 PMCID: PMC8226542 DOI: 10.3390/ijms22126230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 11/25/2022] Open
Abstract
Selective antagonists of thyrotropin-releasing hormone (TRH; pGlu-His-Pro-NH2), in order to enable a better understanding of this peptide’s central functions, have not been identified. Using pGlu-Glu-Pro-NH2 ([Glu2]TRH) as a lead peptide and with modification at its central residue, our studies focused on some of its analogues synthesized as potential functional antagonists of TRH in the rodent brain. Among the peptides studied, the novel isomeric analogue [β-Glu2]TRH was found to suppress the analeptic and antidepressant-like pharmacological activities of TRH without eliciting intrinsic effects in these paradigms. [β-Glu2]TRH also completely reversed TRH’s stimulation of acetylcholine turnover in the rat hippocampus without a cholinergic activity of its own, which was demonstrated through in vivo microdialysis experiments. Altogether, [β-Glu2]TRH emerged as the first selective functional antagonist of TRH’s prominent cholinergic actions, by which this endogenous peptide elicits a vast array of central effects.
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Boghosian JD, Luethy A, Cotten JF. Intravenous and Intratracheal Thyrotropin Releasing Hormone and Its Analog Taltirelin Reverse Opioid-Induced Respiratory Depression in Isoflurane Anesthetized Rats. J Pharmacol Exp Ther 2018; 366:105-112. [PMID: 29674333 DOI: 10.1124/jpet.118.248377] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 04/18/2018] [Indexed: 01/14/2023] Open
Abstract
Thyrotropin releasing hormone (TRH) is a tripeptide hormone and a neurotransmitter widely expressed in the central nervous system that regulates thyroid function and maintains physiologic homeostasis. Following injection in rodents, TRH has multiple effects including increased blood pressure and breathing. We tested the hypothesis that TRH and its long-acting analog, taltirelin, will reverse morphine-induced respiratory depression in anesthetized rats following intravenous or intratracheal (IT) administration. TRH (1 mg/kg plus 5 mg/kg/h, i.v.) and talitrelin (1 mg/kg, i.v.), when administered to rats pretreated with morphine (5 mg/kg, i.v.), increased ventilation from 50% ± 6% to 131% ± 7% and 45% ± 6% to 168% ± 13%, respectively (percent baseline; n = 4 ± S.E.M.), primarily through increased breathing rates (from 76% ± 9% to 260% ± 14% and 66% ± 8% to 318% ± 37%, respectively). By arterial blood gas analysis, morphine caused a hypoxemic respiratory acidosis with decreased oxygen and increased carbon dioxide pressures. TRH decreased morphine effects on arterial carbon dioxide pressure, but failed to impact oxygenation; taltirelin reversed morphine effects on both arterial carbon dioxide and oxygen. Both TRH and talirelin increased mean arterial blood pressure in morphine-treated rats (from 68% ± 5% to 126% ± 12% and 64% ± 7% to 116% ± 8%, respectively; n = 3 to 4). TRH, when initiated prior to morphine (15 mg/kg, i.v.), prevented morphine-induced changes in ventilation; and TRH (2 mg/kg, i.v.) rescued all four rats treated with a lethal dose of morphine (5 mg/kg/min, until apnea). Similar to intravenous administration, both TRH (5 mg/kg, IT) and taltirelin (2 mg/kg, IT) reversed morphine effects on ventilation. TRH or taltirelin may have clinical utility as an intravenous or inhaled agent to antagonize opioid-induced cardiorespiratory depression.
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Affiliation(s)
- James D Boghosian
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (J.D.B., A.L., J.F.C.); and Department of Anesthesia, Kantonsspital Aarau, Aarau, Switzerland (A.L.)
| | - Anita Luethy
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (J.D.B., A.L., J.F.C.); and Department of Anesthesia, Kantonsspital Aarau, Aarau, Switzerland (A.L.)
| | - Joseph F Cotten
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (J.D.B., A.L., J.F.C.); and Department of Anesthesia, Kantonsspital Aarau, Aarau, Switzerland (A.L.)
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Meena CL, Ingole S, Rajpoot S, Thakur A, Nandeker PP, Sangamwar AT, Sharma SS, Jain R. Discovery of a low affinity thyrotropin-releasing hormone (TRH)-like peptide that exhibits potent inhibition of scopolamine-induced memory impairment in mice. RSC Adv 2015; 5:56872-56884. [PMID: 26191403 PMCID: PMC4501038 DOI: 10.1039/c5ra06935a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
TRH-like peptides were synthesized in which the critical N-terminus residue L-pGlu was replaced with various heteroaromatic rings, and the central residue histidine with 1-alkyl-L-histidines. All synthesized TRH-like peptides were evaluated in vitro as agonists in HEK mTRH-R1 and HEK mTRH-R2 cell lines, an expressing receptor binding assay (IC50), and cell signaling assay (EC50). The analeptic potential of the synthesized peptides was evaluated in vivo by using the antagonism of a pentobarbital-induced sleeping time. The peptides 6a, 6c and 6e were found to activate TRH-R2 with potencies (EC50) of 0.002 μM, 0.28 μM and 0.049 μM, respectively. In contrast, for signaling activation of TRH-R1, the same peptides required higher concentration of 0.414 μM, 50 μM and 19.1 μM, respectively in the FLIPR assay. The results showed that these peptides were 207, 178 and 389-fold selective towards TRH-R2 receptor subtype. In the antagonism of a pentobarbital-induced sleeping time assay, peptide 6c showed a 58.5% reduction in sleeping time. The peptide 6c exhibited high stability in rat blood plasma, a superior effect on the scopolamine-induced cognition impairment mice model, safe effects on the cardiovascular system, and general behavior using a functional observation battery (FOB).
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Affiliation(s)
- Chhuttan L. Meena
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Shubdha Ingole
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Satyendra Rajpoot
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Avinash Thakur
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Prajwal P. Nandeker
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Abhay T. Sangamwar
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Shyam S. Sharma
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Rahul Jain
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
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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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Rodríguez-Molina V, Patiño J, Vargas Y, Sánchez-Jaramillo E, Joseph-Bravo P, Charli JL. TRH regulates action potential shape in cerebral cortex pyramidal neurons. Brain Res 2014; 1571:1-11. [PMID: 24842001 DOI: 10.1016/j.brainres.2014.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 05/03/2014] [Accepted: 05/08/2014] [Indexed: 11/28/2022]
Abstract
Thyrotropin releasing hormone (TRH) is a neuropeptide with a wide neural distribution and a variety of functions. It modulates neuronal electrophysiological properties, including resting membrane potential, as well as excitatory postsynaptic potential and spike frequencies. We explored, with whole-cell patch clamp, TRH effect on action potential shape in pyramidal neurons of the sensorimotor cortex. TRH reduced spike and after hyperpolarization amplitudes, and increased spike half-width. The effect varied with dose, time and cortical layer. In layer V, 0.5µM of TRH induced a small increase in spike half-width, while 1 and 5µM induced a strong but transient change in spike half-width, and amplitude; after hyperpolarization amplitude was modified at 5µM of TRH. Cortical layers III and VI neurons responded intensely to 0.5µM TRH; layer II neurons response was small. The effect of 1µM TRH on action potential shape in layer V neurons was blocked by G-protein inhibition. Inhibition of the activity of the TRH-degrading enzyme pyroglutamyl peptidase II (PPII) reproduced the effect of TRH, with enhanced spike half-width. Many cortical PPII mRNA+ cells were VGLUT1 mRNA+, and some GAD mRNA+. These data show that TRH regulates action potential shape in pyramidal cortical neurons, and are consistent with the hypothesis that PPII controls its action in this region.
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Affiliation(s)
- Víctor Rodríguez-Molina
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), AP 70250, México, D.F. 04510, México; Facultad de Medicina, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - Javier Patiño
- Facultad de Medicina, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - Yamili Vargas
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Ave. Universidad 2001, Chamilpa, Cuernavaca, Morelos 62210, México
| | - Edith Sánchez-Jaramillo
- Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría, Ramón de la Fuente Muñíz, México D.F., México
| | - Patricia Joseph-Bravo
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Ave. Universidad 2001, Chamilpa, Cuernavaca, Morelos 62210, México
| | - Jean-Louis Charli
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Ave. Universidad 2001, Chamilpa, Cuernavaca, Morelos 62210, México.
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Thirunarayanan N, Nir EA, Raaka BM, Gershengorn MC. Thyrotropin-releasing hormone receptor type 1 (TRH-R1), not TRH-R2, primarily mediates taltirelin actions in the CNS of mice. Neuropsychopharmacology 2013; 38:950-6. [PMID: 23303050 PMCID: PMC3629383 DOI: 10.1038/npp.2012.256] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Thyrotropin-releasing hormone receptor type 2 (TRH-R2), not TRH-R1, has been proposed to mediate the CNS effects of TRH and its more effective analog taltirelin (TAL). Consistent with this idea, TAL exhibited higher binding affinity and signaling potency at mouse TRH-R2 than TRH-R1 in a model cell system. We used TRH-R1 knockout (R1ko), R2ko and R1/R2ko mice to determine which receptor mediates the CNS effects of TAL. There was no TRH-R1 mRNA in R1ko and R1/R2ko mice and no TRH-R2 mRNA in R2ko and R1/R2ko mice. Specific [(3)H]MeTRH binding to whole brain membranes was 5% of wild type (WT) for R1ko mice, 100% for R2ko mice and 0% for R1/R2ko mice, indicating TRH-R1 is the predominant receptor expressed in the brain. In arousal assays, TAL shortened sleep time with pentobarbital sedation in WT and R2ko mice by 44 and 49% and with ketamine/xylazine sedation by 66 and 55%, but had no effect in R1ko and R1/R2ko mice. In a tail flick assay of nociception, TAL increased response latency by 65 and 70% in WT and R2ko mice, but had no effect in R1ko and R1/R2ko mice. In a tail suspension test of depression-like behavior, TAL increased mobility time by 49 and 37% in WT and R2ko mice, but had no effect in R1ko and R1/R2ko mice. Thus, in contrast to the generally accepted view that the CNS effects of TAL are mediated by TRH-R2, these effects are mediated primarily if not exclusively by TRH-R1 in mice.
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Affiliation(s)
- Nanthakumar Thirunarayanan
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Eshel A Nir
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Bruce M Raaka
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Marvin C Gershengorn
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD, USA,Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), 50 South Drive, Room 4134, Bethesda, MD 20892, USA, Tel: +1 301 451 6305, Fax: +1 301 480 4214, E-mail:
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Wallis M. Molecular evolution of the thyrotrophin-releasing hormone precursor in vertebrates: insights from comparative genomics. J Neuroendocrinol 2010; 22:608-19. [PMID: 20298454 DOI: 10.1111/j.1365-2826.2010.01996.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human preprothyrotrophin-releasing hormone (ppTRH) includes six copies of the TRH sequence, the rat and mouse precursors have five, and those of non-mammalian vertebrates have up to eight. In the present study, the evolutionary basis of this variation was investigated using ppTRH gene sequences extracted from available vertebrate genomic databases. A structure based on eight TRH repeats appears to be the norm for non-mammalian vertebrates, but in all mammals except monotremes this number is reduced to a maximum of six. In some species, one (or more) of the TRH repeats has been mutated, probably rendering it functionless and, in a few species, one or two copies of the TRH sequence have been deleted completely. Sequences of regions between the TRH sequences are poorly conserved, despite reports that several active peptides are produced from these regions. The 5' untranslated region of ppTRH is also very variable but, in eutherians, the promoter region immediately upstream of the gene is quite strongly conserved. In particular, those sequences identified as being involved in transcriptional regulation are well conserved in most eutherians, although they are largely absent from other vertebrates. In most species, gene order around the ppTRH locus is conserved, although exceptions include man and chimpanzee, as well as rat and mouse. The comparative genomics approach thus provides a wider view than previously available of the range of ppTRH genes in vertebrates, and of the species specificity displayed by this molecule.
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Affiliation(s)
- M Wallis
- Biochemistry Department, School of Life Sciences, University of Sussex, Brighton, UK.
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