1
|
TRH in the nucleus accumbens acts downstream to α-MSH to decrease food intake in rats. Neurosci Lett 2020; 739:135403. [PMID: 32980456 DOI: 10.1016/j.neulet.2020.135403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/11/2020] [Accepted: 09/21/2020] [Indexed: 12/23/2022]
Abstract
Feeding-regulatory peptides such as thyrotropin-releasing hormone (TRH), α-melanocyte-stimulating hormone (α-MSH) and their receptors are expressed in brain regions involved in the homeostatic and hedonic control of food intake, such as the hypothalamus and the mesolimbic system, respectively. The nucleus accumbens (NAc) is part of the latter, a brain circuit involved in processing reward stimuli and the appetitive motivation of feeding. When TRH or α-MSH are administered in the NAc, both decrease food intake, through activating their respective receptors, TRH-R1 and MC4R. The actions of α-MSH as a homeostatic feeding-regulator involves the increase of hypothalamic TRH expression, thus, we aimed to identify whether TRH signaling in the NAc was also participating in α-MSH-induced reduction of food intake. α-MSH administration in the NAc of 48 h fasted rats reduced their food intake during the 2-h period of refeeding, increased accumbal TRH mRNA expression and decreased that of MC4R. Such downregulated MC4R mRNA levels implied a compensatory decrease of α-MSH actions in the NAc after the previous pathway stimulation. The co-administration of α-MSH along with an antisense oligonucleotide directed against pro-TRH mRNA in the NAc impaired the α-MSH-induced feeding reduction, supporting that the accumbal TRHergic pathway is downstream of α-MSH actions to inhibit feeding. Our results suggested that TRH in the NAc mediates some effects of α-MSH on inhibition of food intake; this supports the role of TRH not only as a homeostatic regulator but also as modulating the motivational aspects of feeding.
Collapse
|
2
|
Kin K, Yasuhara T, Kawauchi S, Kameda M, Hosomoto K, Tomita Y, Umakoshi M, Kuwahara K, Kin I, Kidani N, Morimoto J, Sasaki T, Date I. Lithium counteracts depressive behavior and augments the treatment effect of selective serotonin reuptake inhibitor in treatment-resistant depressed rats. Brain Res 2019; 1717:52-59. [DOI: 10.1016/j.brainres.2019.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/24/2019] [Accepted: 04/02/2019] [Indexed: 12/28/2022]
|
3
|
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.
Collapse
|
4
|
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.
Collapse
Affiliation(s)
- Gaia A Scalabrino
- School of Biochemistry and Immunology and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Kelly JA, Scalabrino GA, Slator GR, Cullen AA, Gilmer JF, Lloyd DG, Bennett GW, Bauer K, Tipton KF, Williams CH. Structure-activity studies with high-affinity inhibitors of pyroglutamyl-peptidase II. Biochem J 2005; 389:569-76. [PMID: 15799721 PMCID: PMC1175135 DOI: 10.1042/bj20041722] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Inhibitors of PPII (pyroglutamyl-peptidase II) (EC 3.4.19.6) have potential applications as investigative and therapeutic agents. The rational design of inhibitors is hindered, however, by the lack of an experimental structure for PPII. Previous studies have demonstrated that replacement of histidine in TRH (thyrotropin-releasing hormone) with asparagine produces a competitive PPII inhibitor (Ki 17.5 microM). To gain further insight into which functional groups are significant for inhibitory activity, we investigated the effects on inhibition of structural modifications to Glp-Asn-ProNH2 (pyroglutamyl-asparaginyl-prolineamide). Synthesis and kinetic analysis of a diverse series of carboxamide and C-terminally extended Glp-Asn-ProNH2 analogues were undertaken. Extensive quantitative structure-activity relationships were generated, which indicated that key functionalities in the basic molecular structure of the inhibitors combine in a unique way to cause PPII inhibition. Data from kinetic and molecular modelling studies suggest that hydrogen bonding between the asparagine side chain and PPII may provide a basis for the inhibitory properties of the asparagine-containing peptides. Prolineamide appeared to be important for interaction with the S2' subsite, but some modifications were tolerated. Extension of Glp-Asn-ProNH2 with hydrophobic amino acids at the C-terminus led to a novel set of PPII inhibitors active in vitro at nanomolar concentrations. Such inhibitors were shown to enhance recovery of TRH released from rat brain slices. Glp-Asn-Pro-Tyr-Trp-Trp-7-amido-4-methylcoumarin displayed a Ki of 1 nM, making it the most potent competitive PPII inhibitor described to date. PPII inhibitors with this level of potency should find application in exploring the biological functions of TRH and PPII, and potentially provide a basis for development of novel therapeutics.
Collapse
Affiliation(s)
- Julie A Kelly
- Department of Biochemistry, Trinity College Dublin, Dublin 2, Ireland.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Eugene Pekary A, Faull KF, Paulson M, Lloyd RL, Sattin A. TRH-like antidepressant peptide, pyroglutamyltyroslyprolineamide, occurs in rat brain. JOURNAL OF MASS SPECTROMETRY : JMS 2005; 40:1232-6. [PMID: 16124040 DOI: 10.1002/jms.904] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We have previously reported the occurrence of pGlu-Glu-Pro-NH(2)(Glu-TRH, EEP), Val-TRH, Tyr-TRH, Leu-TRH, Phe-TRH, and Trp-TRH in rat brain using a combination of HPLC and radioimmunoassays with antibodies that cross-react with the general structure pGlu-X-Pro-NH(2) where 'X' maybe any amino acid residue (Peptides 2004; 25 : 647). This new family of TRH-like peptides, along with TRH (pGlu-His-Pro-NH(2)), has neuroprotective, anticonvulsant, antidepressant, euphoric, anti-amnesic, and analeptic effects. We now report that a combination of affinity chromatography using a rabbit antibody specific for Tyr-TRH and Phe-TRH, along with HPLC and tandem mass spectrometry operating in the multiple reaction monitoring (MRM) mode, provide conclusive evidence for the presence of Tyr-TRH in rat brain. Furthermore, synthetic Tyr-TRH is active in the Porsolt Swim Test suggesting that it is a fourth member of this family of in vivo neuroregulatory agents that have psychopharmacotherapeutic properties.
Collapse
Affiliation(s)
- A Eugene Pekary
- Research Service, VA Greater Los Angeles Healthcare System and Department of Medicine, University of California, Los Angeles, CA 90073, USA.
| | | | | | | | | |
Collapse
|
7
|
Chang K, Karchemskiy A, Barnea-Goraly N, Garrett A, Simeonova DI, Reiss A. Reduced amygdalar gray matter volume in familial pediatric bipolar disorder. J Am Acad Child Adolesc Psychiatry 2005; 44:565-73. [PMID: 15908839 DOI: 10.1097/01.chi.0000159948.75136.0d] [Citation(s) in RCA: 214] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Subcortical limbic structures have been proposed to be involved in the pathophysiology of adult and pediatric bipolar disorder (BD). We sought to study morphometric characteristics of these structures in pediatric subjects with familial BD compared with healthy controls. METHOD Twenty children and adolescents with BD I (mean age = 14.6 years, four females) and 20 healthy age, gender, and IQ-matched controls underwent high-resolution magnetic resonance imaging at 3 T. Patients were mostly euthymic and most were taking medications. Amygdala, hippocampus, thalamus, and caudate volumes were determined by manual tracings from researchers blinded to diagnosis. Analyses of covariance were performed, with total brain volume, age, and gender as covariates. RESULTS No differences were found in the volumes of hippocampus, caudate, and thalamus between subjects with BD and controls. Subjects with BD had smaller volumes in the left and right amygdala, driven by reductions in gray matter volume. Exploratory analyses revealed that subjects with BD with past lithium or valproate exposure tended to have greater amygdalar gray matter volume than subjects with BD without such exposure. CONCLUSIONS Children and adolescents with early-onset BD may have reduced amygdalar volumes, consistent with other studies in this population. Prolonged medication exposure to lithium or valproate may account for findings in adults with BD of increased amygdalar volume relative to controls.
Collapse
Affiliation(s)
- Kiki Chang
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305-5540, USA.
| | | | | | | | | | | |
Collapse
|
8
|
Visser NFC, Lingeman H, Irth H. Sample preparation for peptides and proteins in biological matrices prior to liquid chromatography and capillary zone electrophoresis. Anal Bioanal Chem 2005; 382:535-58. [PMID: 15834556 DOI: 10.1007/s00216-005-3120-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 01/17/2005] [Accepted: 01/24/2005] [Indexed: 11/30/2022]
Abstract
The determination of peptides and proteins in a biological matrix normally includes a sample-preparation step to obtain a sample that can be injected into a separation system in such a way that peptides and proteins of interest can be determined qualitatively and/or quantitatively. This can be a rather challenging, labourious and/or time-consuming process. The extract obtained after sample preparation is further separated using a compatible separation system. Liquid chromatography (LC) is the generally applied technique for this purpose, but capillary zone electrophoresis (CZE) is an alternative, providing fast, versatile and efficient separations. In this review, the recent developments in the combination of sample-preparation procedures with LC and CZE, for the determination of peptides and proteins, will be discussed. Emphasis will be on purification from and determination in complex biological matrices (plasma, cell lysates, etc.) of these compounds and little attention will be paid to the proteomics area. Additional focus will be put on sample-preparation conditions, which can be 'hard' or 'soft', and on selectivity issues. Selectivity issues will be addressed in combination with the used separation technique and a comparison between LC and CZE will be made.
Collapse
Affiliation(s)
- N F C Visser
- Faculty of Sciences, Division of Chemistry, Department of Analytical Chemistry and Applied Spectroscopy, Vrije Universiteit Amsterdam, de Boelelaan 1083, 1081, HV, Amsterdam, The Netherlands
| | | | | |
Collapse
|
9
|
Pekary AE, Sattin A, Meyerhoff JL, Chilingar M. Valproate modulates TRH receptor, TRH and TRH-like peptide levels in rat brain. Peptides 2004; 25:647-58. [PMID: 15165721 DOI: 10.1016/j.peptides.2004.01.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2003] [Accepted: 01/27/2004] [Indexed: 01/01/2023]
Abstract
We have tested our hypothesis that alterations in the levels of TRH receptors, and the synthesis and release of tripeptide TRH, and other neurotropic TRH-like peptides mediate some of the mood stabilizing effects of valproate (Valp). We have directly compared the effect of 1 week of feeding two major mood stabilizers, Valp and lithium chloride (LiCl) on TRH binding in limbic and extra-limbic regions of male WKY rats. Valp increased TRH receptor levels in nucleus accumbens and frontal cortex. Li increased TRH receptor binding in amygdala, posterior cortex and cerebellum. The acute, chronic and withdrawal effects of Valp on brain levels of TRH (pGlu-His-Pro-NH2, His-TRH) and five other TRH-like peptides, Glu-TRH, Val-TRH, Tyr-TRH, Leu-TRH and Phe-TRH were measured by combined HPLC and RIA. Acute treatment increased TRH and TRH-like peptide levels within most brain regions, most strikingly in pyriform cortex. The fold increases (in parentheses) were: Val-TRH (58), Phe-TRH (54), Tyr-TRH (25), TRH (9), Glu-TRH (4) and Leu-TRH (3). We conclude that the mood stabilizing effects of Valp may be due, at least in part, to its ability to alter TRH and TRH-like peptide, and TRH receptor levels in the limbic system and other brain regions implicated in mood regulation and behavior.
Collapse
Affiliation(s)
- A Eugene Pekary
- Research Services, West Los Angeles Va Medical Center, CA 90073, USA.
| | | | | | | |
Collapse
|
10
|
Abstract
Thyrotropin-releasing hormone (TRH) is localized in the brain hypothalamus and stimulates the secretion and synthesis of pituitary thyrotropin (TSH). Although TRH deficiency caused by artificial hypothalamic destructions has been reported to result in significant decreases in TSH secretion in rodents, clinical observations from the patients with possible TRH deficiency did not entirely agree with these animal results. Because of its ubiquitous distribution throughout the brain and in the peripheral tissues, TRH has been suggested to possess a wide variety of functions in these regions. However, the neurobehavioral and peripheral actions of TRH still remains to be established. It has been, therefore, anticipated that detailed analysis of TRH-knockout mice might provide insight into the physiological significance of endogenous TRH. The present review focuses on the phenotypic findings of mice deficient in TRH.
Collapse
Affiliation(s)
- Masanobu Yamada
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | | | | |
Collapse
|
11
|
Sattin A, Pekary AE, Lloyd RL, Paulson M, Meyerhoff JA, Hinkle PM, Faull K. TRH and Related Peptides. Ann N Y Acad Sci 2003; 1003:458-60. [PMID: 14684488 DOI: 10.1196/annals.1300.053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- A Sattin
- Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, California 90073, USA.
| | | | | | | | | | | | | |
Collapse
|
12
|
|