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Speranza L, Molinari M, Volpicelli F, Lacivita E, Leopoldo M, Pulcrano S, Carlo Bellenchi G, Perrone Capano C, Crispino M. Modulation of neuronal morphology by antipsychotic drug: Involvement of serotonin receptor 7. Brain Res 2024; 1830:148815. [PMID: 38387714 DOI: 10.1016/j.brainres.2024.148815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/26/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
Antipsychotic drugs (APDs) are the primary pharmacological treatment for schizophrenia, a complex disorder characterized by altered neuronal connectivity. Atypical or second-generation antipsychotics, such as Risperidone (RSP) and Clozapine (CZP) predominantly block dopaminergic D2 and serotonin receptor 2A (5-HT2A) neurotransmission. Both compounds also exhibit affinity for the 5-HT7R, with RSP acting as an antagonist and CZP as an inverse agonist. Our study aimed to determine whether RSP and CZP can influence neuronal morphology through a 5-HT7R-mediated mechanism. Here, we demonstrated that CZP promotes neurite outgrowth of early postnatal cortical neurons, and the 5-HT7R mediates its effect. Conversely, RSP leads to a reduction of neurite length of early postnatal cortical neurons, in a 5-HT7R-independent way. Furthermore, we found that the effects of CZP, mediated by 5-HT7R activation, require the participation of ERK and Cdk5 kinase pathways. At the same time, the modulation of neurite length by RSP does not involve these pathways. In conclusion, our findings provide valuable insights into the morphological changes induced by these two APDs in neurons and elucidate some of the associated molecular pathways. Investigating the 5-HT7R-dependent signaling pathways underlying the neuronal morphogenic effects of APDs may contribute to the identification of novel targets for the treatment of schizophrenia.
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Affiliation(s)
- Luisa Speranza
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy
| | - Marta Molinari
- Telethon Institute of Genetics & Medicine, Via Campi Flegrei, 34, 80078 Pozzuoli, Naples, Italy
| | - Floriana Volpicelli
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy.
| | - Enza Lacivita
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari Aldo Moro, 70125 Bari, Italy
| | - Marcello Leopoldo
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari Aldo Moro, 70125 Bari, Italy
| | - Salvatore Pulcrano
- Institute of Genetics and Biophysics "A. Buzzati-Traverso", CNR, 80131 Naples, Italy
| | - Gian Carlo Bellenchi
- Institute of Genetics and Biophysics "A. Buzzati-Traverso", CNR, 80131 Naples, Italy
| | - Carla Perrone Capano
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy
| | - Marianna Crispino
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy
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2
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Jeong JH, Lee H, Kim D, Park E, Woo J, Cho Y, Keum G, Lee A, Kang T, Kim J, Choo H, Lee S, Jeon B. Identification of an Antagonist Targeting G Protein and β-Arrestin Signaling Pathways of 5-HT 7R. ACS Chem Neurosci 2024; 15:1026-1041. [PMID: 38387042 DOI: 10.1021/acschemneuro.3c00738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024] Open
Abstract
In consideration of the limited number of FDA-approved drugs for autism spectrum disorder (ASD), significant efforts have been devoted to identifying novel drug candidates. Among these, 5-HT7R modulators have garnered considerable attention due to their potential in alleviating autism-like behaviors in ASD animal models. In this study, we designed and synthesized biphenyl-3-ylmethylpyrrolidines 3 and biphenyl-3-yl-dihydroimidazoles 4 as 5-HT7R modulators. Through extensive biological tests of 3 and 4 in G protein and β-arrestin signaling pathways of 5-HT7R, it was determined that 2-(2'-methoxy-[1,1'-biphenyl]-3-yl)-4,5-dihydro-1H-imidazole 4h acted as a 5-HT7R antagonist in both signaling pathways. In in vivo study with Shank3-/- transgenic (TG) mice, the self-grooming behavior test was performed with 4h, resulting in a significant reduction in the duration of self-grooming. In addition, an immunohistochemical experiment with 4h restored reduced neurogenesis in Shank3-/- TG mice, which is confirmed by the quantification of doublecortin (DCX) positive neurons, suggesting the promising therapeutic potential of 4h.
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Affiliation(s)
- Jeong Hyun Jeong
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Haeun Lee
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Doyoung Kim
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Eunseo Park
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Jiwan Woo
- Research Animal Resource Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Yakdol Cho
- Research Animal Resource Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Gyochang Keum
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Ansoo Lee
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Taek Kang
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Jeongjin Kim
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Hyunah Choo
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Sanghee Lee
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Byungsun Jeon
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology, Seongbuk-gu, Seoul 02792, Republic of Korea
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3
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Fukuyama K, Motomura E, Okada M. A Novel Gliotransmitter, L-β-Aminoisobutyric Acid, Contributes to Pathophysiology of Clinical Efficacies and Adverse Reactions of Clozapine. Biomolecules 2023; 13:1288. [PMID: 37759688 PMCID: PMC10526296 DOI: 10.3390/biom13091288] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/18/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
Clozapine is listed as one of the most effective antipsychotics and has been approved for treating treatment-resistant schizophrenia (TRS); however, several type A and B adverse reactions, including weight gain, metabolic complications, cardiotoxicity, convulsions, and discontinuation syndromes, exist. The critical mechanisms of clinical efficacy for schizophrenia, TRS, and adverse reactions of clozapine have not been elucidated. Recently, the GABA isomer L-β-aminoisobutyric acid (L-BAIBA), a protective myokine in the peripheral organs, was identified as a candidate novel transmission modulator in the central nervous system (CNS). L-BAIBA activates adenosine monophosphate-activated protein kinase (AMPK) signalling in both the peripheral organs and CNS. Activated AMPK signalling in peripheral organs is an established major target for treating insulin-resistant diabetes, whereas activated AMPK signalling in the hypothalamus contributes to the pathophysiology of weight gain and metabolic disturbances. Clozapine increases L-BAIBA synthesis in the hypothalamus. In addition, the various functions of L-BAIBA in the CNS have recently been elucidated, including as an activator of GABA-B and group-III metabotropic glutamate (III-mGlu) receptors. Considering the expressions of GABA-B and III-mGlu receptors (localised in the presynaptic regions), the activation of GABA-B and III-mGlu receptors can explain the distinct therapeutic advantages of clozapine in schizophrenia or TRS associated with N-methyl-D-aspartate (NMDA) receptor disturbance compared with other atypical antipsychotics via the inhibition of the persistent tonic hyperactivation of thalamocortical glutamatergic transmission in the prefrontal cortex. L-BAIBA has also been identified as a gliotransmitter, and a detailed exploration of the function of L-BAIBA in tripartite synaptic transmission can further elucidate the pathophysiology of effectiveness for treating TRS and/or specific adverse reactions of clozapine.
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Affiliation(s)
| | | | - Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (E.M.)
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Therapeutic Potential and Limitation of Serotonin Type 7 Receptor Modulation. Int J Mol Sci 2023; 24:ijms24032070. [PMID: 36768393 PMCID: PMC9916679 DOI: 10.3390/ijms24032070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/15/2023] [Accepted: 01/18/2023] [Indexed: 01/21/2023] Open
Abstract
Although a number of mood-stabilising atypical antipsychotics and antidepressants modulate serotonin type 7 receptor (5-HT7), the detailed contributions of 5-HT7 function to clinical efficacy and pathophysiology have not been fully understood. The mood-stabilising antipsychotic agent, lurasidone, and the serotonin partial agonist reuptake inhibitor, vortioxetine, exhibit higher binding affinity to 5-HT7 than other conventional antipsychotics and antidepressants. To date, the initially expected rapid onset of antidepressant effects-in comparison with conventional antidepressants or mood-stabilising antipsychotics-due to 5-HT7 inhibition has not been observed with lurasidone and vortioxetine; however, several clinical studies suggest that 5-HT7 inhibition likely contributes to quality of life of patients with schizophrenia and mood disorders via the improvement of cognition. Furthermore, recent preclinical studies reported that 5-HT7 inhibition might mitigate antipsychotic-induced weight gain and metabolic complication by blocking other monoamine receptors. Further preclinical studies for the development of 5-HT7 modulation against neurodevelopmental disorders and neurodegenerative diseases have been ongoing. To date, various findings from various preclinical studies indicate the possibility that 5-HT7 modifications can provide two independent strategies. The first is that 5-HT7 inhibition ameliorates the dysfunction of inter-neuronal transmission in mature networks. The other is that activation of 5-HT7 can improve transmission dysfunction due to microstructure abnormality in the neurotransmission network-which could be unaffected by conventional therapeutic agents-via modulating intracellular signalling during the neurodevelopmental stage or via loss of neural networks with aging. This review attempts to describe the current and novel clinical applications of 5-HT7 modulation based on preclinical findings.
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Okubo R, Hasegawa T, Fukuyama K, Shiroyama T, Okada M. Current Limitations and Candidate Potential of 5-HT7 Receptor Antagonism in Psychiatric Pharmacotherapy. Front Psychiatry 2021; 12:623684. [PMID: 33679481 PMCID: PMC7930824 DOI: 10.3389/fpsyt.2021.623684] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/29/2021] [Indexed: 12/13/2022] Open
Abstract
Several mood-stabilizing atypical antipsychotics and antidepressants weakly block serotonin (5-HT) receptor type-7 (5-HT7R); however, the contributions of 5-HT7R antagonism to clinical efficacy and pathophysiology are yet to be clarified. A novel mood-stabilizing antipsychotic agent, lurasidone exhibits predominant binding affinity to 5-HT7R when compared with other monoamine receptors. To date, we have failed to discover the superior clinical efficacy of lurasidone on schizophrenia, mood, or anxiety disorders when compared with conventional mood-stabilizing atypical antipsychotics; however, numerous preclinical findings have indicated the possible potential of 5-HT7R antagonism against several neuropsychiatric disorders, as well as the generation of novel therapeutic options that could not be expected with conventional atypical antipsychotics. Traditional experimental techniques, electrophysiology, and microdialysis have demonstrated that the effects of 5-HT receptor type-1A (5-HT1AR) and 5-HT7R on neurotransmission are in contrast, but the effect of 5-HT1AR is more predominant than that of 5-HT7R, resulting in an insufficient understanding of the 5-HT7R function in the field of psychopharmacology. Accumulating knowledge regarding the pharmacodynamic profiles of 5-HT7R suggests that 5-HT7R is one of the key players in the establishment and remodeling of neural development and cytoarchitecture during the early developmental stage to the mature brain, and dysfunction or modulation of 5-HT7R is linked to the pathogenesis/pathophysiology of neuropsychiatric and neurodevelopmental disorders. In this review, to explore candidate novel applications for the treatment of several neuropsychiatric disorders, including mood disorders, schizophrenia, and other cognitive disturbance disorders, we discuss perspectives of psychopharmacology regarding the effects of 5-HT7R antagonism on transmission and intracellular signaling systems, based on preclinical findings.
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Affiliation(s)
- Ruri Okubo
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Toshiki Hasegawa
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Kouji Fukuyama
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Takashi Shiroyama
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Motohiro Okada
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
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6
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Fernandez TJ, De Maria M, Lobingier BT. A cellular perspective of bias at G protein-coupled receptors. Protein Sci 2020; 29:1345-1354. [PMID: 32297394 DOI: 10.1002/pro.3872] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/10/2020] [Accepted: 04/10/2020] [Indexed: 12/17/2022]
Abstract
G protein-coupled receptors (GPCRs) modulate cell function over short- and long-term timescales. GPCR signaling depends on biochemical parameters that define the what, when, and where of receptor function: what proteins mediate and regulate receptor signaling, where within the cell these interactions occur, and how long these interactions persist. These parameters can vary significantly depending on the activating ligand. Collectivity, differential agonist activity at a GPCR is called bias or functional selectivity. Here we review agonist bias at GPCRs with a focus on ligands that show dramatically different cellular responses from their unbiased counterparts.
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Affiliation(s)
- Thomas J Fernandez
- Department of Chemical Physiology and Biochemistry, Oregon Health and Sciences University, Portland, Oregon, USA
| | - Monica De Maria
- Department of Chemical Physiology and Biochemistry, Oregon Health and Sciences University, Portland, Oregon, USA
| | - Braden T Lobingier
- Department of Chemical Physiology and Biochemistry, Oregon Health and Sciences University, Portland, Oregon, USA
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7
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Evaluation of 5-HT7 receptor antagonism for the treatment of anxiety, depression, and schizophrenia through the use of receptor-deficient mice. Behav Brain Res 2019; 360:270-278. [DOI: 10.1016/j.bbr.2018.12.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 12/09/2018] [Accepted: 12/09/2018] [Indexed: 11/21/2022]
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8
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Schoretsanitis G, Spina E, Hiemke C, de Leon J. A systematic review and combined analysis of therapeutic drug monitoring studies for long-acting paliperidone. Expert Rev Clin Pharmacol 2018; 11:1237-1253. [DOI: 10.1080/17512433.2018.1549489] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Georgios Schoretsanitis
- University Hospital of Psychiatry, Bern, Switzerland
- Department of Psychiatry, Psychotherapy and Psychosomatics, and JARA-Translational Brain Medicine, RWTH Aachen University, Aachen, Germany
| | - Edoardo Spina
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Christoph Hiemke
- Department of Psychiatry and Psychotherapy, University Medical Center of Mainz, Mainz, Germany
| | - Jose de Leon
- University of Kentucky Mental Health Research Center at Eastern State Hospital, Lexington, KY, USA
- Psychiatry and Neurosciences Research Group (CTS-549), Institute of Neurosciences, University of Granada, Granada, Spain
- Biomedical Research Centre in Mental Health Net (CIBERSAM), Santiago Apostol Hospital, University of the Basque Country, Vitoria, Spain
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9
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Maxwell J, Gleason SD, Falcone J, Svensson K, Balcer OM, Li X, Witkin JM. Effects of 5-HT 7 receptor antagonists on behaviors of mice that detect drugs used in the treatment of anxiety, depression, or schizophrenia. Behav Brain Res 2018; 359:467-473. [PMID: 30471311 DOI: 10.1016/j.bbr.2018.11.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 10/27/2022]
Abstract
5-HT7 receptors have been suggested to play a role in the regulation of psychiatric disorders. The experimental literature however is not fully consistent on this possibility. Two selective 5-HT7 receptor antagonists, DR-4004 and SB-269970, were evaluated in mouse models used to detect drugs used to treat anxiety, depression, or schizophrenia. A 5-HT-induced hypothermia assay was used to define the doses of DR-4004 and SB-269970 predicted to impact 5-HT7 receptors in the brain in vivo. 5-HT produced hypothermia in wildtype mice by either i.p. or i.c.v. routes but did not in 5-HT7 receptor knockout mice. 5-HT-induced hypothermia was not attenuated by drugs selectively blocking alpha1 or 5-HT1A receptors. Doses of DR-4004 and SB-269970 that blocked 5-HT-induced hypothermia, did not display significant anxiolytic-like (elevated plus maze; vogel conflict) or antidepressant-like efficacy (tail-suspension test) in mouse models. These compounds did demonstrate some antipsychotic-like properties in the PCP-induced hyperactivity assay and anxiolytic/anti-stress effects in the stress-induced cGMP assay. Negative findings were substantiated by positive control drugs that were active in each assay system. We conclude that 5-HT-induced hypothermia can be used to estimate blockade of central 5-HT7 receptors. Effects of DR-4004 and SB-269970 in animal models are generally consistent with the experimental literature that the evidence is mixed or not robust regarding the potential efficacy of 5-HT7 receptor antagonism in the treatment of anxiety, depression, or schizophrenia.
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Affiliation(s)
- Julia Maxwell
- Neuroscience Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Scott D Gleason
- Neuroscience Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Julie Falcone
- Neuroscience Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Kjell Svensson
- Neuroscience Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Olivia M Balcer
- Neuroscience Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Xia Li
- Neuroscience Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Jeffrey M Witkin
- Neuroscience Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA.
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Wixey JA, Reinebrant HE, Chand KK, Buller KM. Disruption to the 5-HT 7 Receptor Following Hypoxia-Ischemia in the Immature Rodent Brain. Neurochem Res 2018; 43:711-720. [PMID: 29357019 DOI: 10.1007/s11064-018-2473-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/06/2018] [Accepted: 01/09/2018] [Indexed: 10/18/2022]
Abstract
It has become increasingly evident the serotonergic (5-hydroxytryptamine, 5-HT) system is an important central neuronal network disrupted following neonatal hypoxic-ischemic (HI) insults. Serotonin acts via a variety of receptor subtypes that are differentially associated with behavioural and cognitive mechanisms. The 5-HT7 receptor is purported to play a key role in epilepsy, anxiety, learning and memory and neuropsychiatric disorders. Furthermore, the 5-HT7 receptor is highly localized in brain regions damaged following neonatal HI insults. Utilising our well-established neonatal HI model in the postnatal day 3 (P3) rat pup we demonstrated a significant decrease in levels of the 5-HT7 protein in the frontal cortex, thalamus and brainstem one week after insult. We also observed a relative decrease in both the cytosolic and membrane fractions of 5-HT7. The 5-HT7 receptor was detected on neurons throughout the cortex and thalamus, and 5-HT cell bodies in the brainstem. However we found no evidence of 5-HT7 co-localisation on microglia or astrocytes. Moreover, minocycline treatment did not significantly prevent the HI-induced reductions in 5-HT7. In conclusion, neonatal HI injury caused significant disruption to 5-HT7 receptors in the forebrain and brainstem. Yet the use of minocycline to inhibit activated microglia, did not prevent the HI-induced changes in 5-HT7 expression.
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Affiliation(s)
- Julie A Wixey
- Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, QLD, 4029, Australia.
| | - Hanna E Reinebrant
- Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, QLD, 4029, Australia.,Mater Research Institute, The University of Queensland (MRI-UQ), Brisbane, Australia
| | - Kirat K Chand
- Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, QLD, 4029, Australia
| | - Kathryn M Buller
- Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, QLD, 4029, Australia
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11
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Iglesias A, Cimadevila M, Cadavid MI, Loza MI, Brea J. Serotonin-2A homodimers are needed for signalling via both phospholipase A 2 and phospholipase C in transfected CHO cells. Eur J Pharmacol 2017; 800:63-69. [PMID: 28216047 DOI: 10.1016/j.ejphar.2017.02.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/16/2017] [Accepted: 02/16/2017] [Indexed: 01/05/2023]
Abstract
Different ligands differentially activate phospholipase A2 (PLA2) and phospholipase C (PLC) signalling pathways that are coupled to the serotonin 2A (5-HT2A) receptor, a class-A G-protein coupled receptor (GPCR). The serotonin 5-HT2A receptor has been shown to be expressed as a homodimer displaying some ligands negative cooperativity between protomers in the PLA2 signalling pathway. We hypothesized that the homodimeric complex is the minimum functional unit required for activation of the PLA2 and PLC pathways by the serotonin 5-HT2A receptor. To investigate this hypothesis, we partially blocked the serotonin 5-HT2A receptors with ritanserin and measured PLA2 and PLC activity simultaneously. We subsequently added the competitive antagonist spiperone to release the inactivator through a crosstalk mechanism and thus allow the dimer to return to a reactive state. Partial inactivation of the homodimer by ritanserin binding decreased the activity of the receptor by 59±13% and 70±4% in the PLA2 and PLC pathways respectively (P<0.001), with no difference in the potency of the serotonin (5-HT) was observed. The subsequent binding of spiperone released ritanserin due to the crosstalk between protomers and recovery of the receptor activity to 74±7% and 72±4%. Negative cooperativity between protomers in the dimer was maintained during arachidonic acid (AA) release after blocking ritanserin, as indicated by the biphasic inhibition curves for clozapine over 1μM serotonin (5-HT) in these conditions. These findings provide evidence that serotonin 5-HT2A receptors must be expressed as homodimers in order to activate both the PLA2 and PLC signalling pathways.
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Affiliation(s)
- Alba Iglesias
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain
| | - Marta Cimadevila
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain
| | - María Isabel Cadavid
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain
| | - María Isabel Loza
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain.
| | - José Brea
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidade de Santiago de Compostela, Avenida de Barcelona 22, 15782 Santiago de Compostela, Spain.
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Zareifopoulos N, Papatheodoropoulos C. Effects of 5-HT-7 receptor ligands on memory and cognition. Neurobiol Learn Mem 2016; 136:204-209. [PMID: 27780766 DOI: 10.1016/j.nlm.2016.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/12/2016] [Accepted: 10/21/2016] [Indexed: 10/20/2022]
Abstract
The 5-HT7R is the most recently cloned serotonin receptor and thus one the least studied. Many drugs, experimental and in clinical use bind to 5-HT7 with high affinity, though their effects have yet to be clearly elucidated. Its physiological function, though not completely clear, is mostly associated with learning and memory, with both agonists and antagonists possessing subtle procognitive and promnesic properties. We consider it a promising area of research, though still in its infancy, which may one day lead to clinical benefits for patients with various afflictions characterised by cognitive dysfunction, particularily autism spectrum disorder, fragile X syndrome and Alzheimer's disease.
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Chan JD, Grab T, Marchant JS. Kinetic profiling an abundantly expressed planarian serotonergic GPCR identifies bromocriptine as a perdurant antagonist. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2016; 6:356-363. [PMID: 27397764 PMCID: PMC5196488 DOI: 10.1016/j.ijpddr.2016.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 06/20/2016] [Indexed: 02/02/2023]
Abstract
The diversity and uniqueness of flatworm G protein coupled receptors (GPCRs) provides impetus for identifying ligands useful as tools for studying flatworm biology, or as therapeutics for treating diseases caused by parasitic flatworm infections. To catalyse this discovery process, technologies optimized for mammalian GPCR high throughput screening need be transposed for screening flatworm GPCRs. Here, we demonstrate the utility of a genetically encoded cAMP biosensor for resolving the properties of an abundantly expressed planarian serotonergic GPCR (S7.1R). Application of this methodology resolved the real time kinetics of GPCR modulation by ligands and demonstrated a marked difference in the kinetic action of antagonists at S7.1R. Notably, bromocriptine caused a protracted inhibition of S7.1R activity in vitro and a protracted paralysis of planarian movement, replicating the effect of S7.1R in vivo RNAi. The lengthy inhibition of function caused by bromocriptine at this abundantly expressed GPCR provides a useful tool to ablate serotonergic signaling in vivo, and is a noteworthy feature for exploitation as an anthelmintic vulnerability. Application of a real time cAMP biosensor to study a planarian serotonergic GPCR. The biosensor reveals differential kinetics of 5-HT GPCR inhibition by antagonists. Bromocriptine causes a persistent signaling inhibition and paralysis of intact worms. Bromocriptine action akin to a ‘pharmacological knockout’ of receptor function.
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Affiliation(s)
- John D Chan
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Thomas Grab
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Jonathan S Marchant
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA; Stem Cell Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
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14
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Chan JD, McCorvy JD, Acharya S, Johns ME, Day TA, Roth BL, Marchant JS. A Miniaturized Screen of a Schistosoma mansoni Serotonergic G Protein-Coupled Receptor Identifies Novel Classes of Parasite-Selective Inhibitors. PLoS Pathog 2016; 12:e1005651. [PMID: 27187180 PMCID: PMC4871480 DOI: 10.1371/journal.ppat.1005651] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/30/2016] [Indexed: 01/31/2023] Open
Abstract
Schistosomiasis is a tropical parasitic disease afflicting ~200 million people worldwide and current therapy depends on a single drug (praziquantel) which exhibits several non-optimal features. These shortcomings underpin the need for next generation anthelmintics, but the process of validating physiologically relevant targets (‘target selection’) and pharmacologically profiling them is challenging. Remarkably, even though over a quarter of current human therapeutics target rhodopsin-like G protein coupled receptors (GPCRs), no library screen of a flatworm GPCR has yet been reported. Here, we have pharmacologically profiled a schistosome serotonergic GPCR (Sm.5HTR) implicated as a downstream modulator of PZQ efficacy, in a miniaturized screening assay compatible with high content screening. This approach employs a split luciferase based biosensor sensitive to cellular cAMP levels that resolves the proximal kinetics of GPCR modulation in intact cells. Data evidence a divergent pharmacological signature between the parasitic serotonergic receptor and the closest human GPCR homolog (Hs.5HTR7), supporting the feasibility of optimizing parasitic selective pharmacophores. New ligands, and chemical series, with potency and selectivity for Sm.5HTR over Hs.5HTR7 are identified in vitro and validated for in vivo efficacy against schistosomules and adult worms. Sm.5HTR also displayed a property resembling irreversible inactivation, a phenomenon discovered at Hs.5HTR7, which enhances the appeal of this abundantly expressed parasite GPCR as a target for anthelmintic ligand design. Overall, these data underscore the feasibility of profiling flatworm GPCRs in a high throughput screening format competent to resolve different classes of GPCR modulators. Further, these data underscore the promise of Sm.5HTR as a chemotherapeutically vulnerable node for development of next generation anthelmintics. Parasitic flatworms express a diverse array of G protein coupled receptors, but our knowledge of their pharmacological profile is limited. No high throughput screen of a flatworm GPCR has been reported, even though these targets have precedent for high druggability and functionality in the chemotherapeutically vulnerable excitable cell niche. The goal of this study was to establish a method for profiling flatworm G protein coupled receptors that can be scaled to high content screening. Using a cAMP biosensor, we have performed a proof of principle miniaturized screen on a schistosome serotonergic GPCR that resolves new ligands that potently and selectivity block 5-HT receptor activity in vitro, and 5-HT evoked responses in schistosomules and adult worms. This approach evidences the pharmacological divergence of a parasitic GPCR from the closest human homolog and a capacity for high content interrogation of flatworm GPCR properties and ligand specificities.
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Affiliation(s)
- John D. Chan
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - John D. McCorvy
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Sreemoyee Acharya
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Malcolm E. Johns
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Timothy A. Day
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Bryan L. Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Division of Chemical Biology and Medicinal Chemistry, Eshelmann School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jonathan S. Marchant
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, United States of America
- Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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15
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Andressen KW, Manfra O, Brevik CH, Ulsund AH, Vanhoenacker P, Levy FO, Krobert KA. The atypical antipsychotics clozapine and olanzapine promote down-regulation and display functional selectivity at human 5-HT7 receptors. Br J Pharmacol 2015; 172:3846-60. [PMID: 25884989 PMCID: PMC4523340 DOI: 10.1111/bph.13169] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 04/01/2015] [Accepted: 04/14/2015] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE Classically, ligands of GPCRs have been classified primarily upon their affinity and efficacy to activate a signal transduction pathway. Recent reports indicate that the efficacy of a particular ligand can vary depending on the receptor-mediated response measured (e.g. activating G proteins, other downstream responses, internalization). Previously, we reported that inverse agonists induce both homo- and heterologous desensitization, similar to agonist stimulation, at the Gs -coupled 5-HT7 receptor. The primary objective of this study was to determine whether different inverse agonists at the 5-HT7 receptor also induce internalization and/or degradation of 5-HT7 receptors. EXPERIMENTAL APPROACH HEK293 cells expressing 5-HT7(a, b or d) receptors were pre-incubated with 5-HT, clozapine, olanzapine, mesulergine or SB269970 and their effects upon receptor density, AC activity, internalization, recruitment of β-arrestins and lysosomal trafficking were measured. KEY RESULTS The agonist 5-HT and three out of four inverse agonists tested increased internalization independently of β-arrestin recruitment. Among these, only the atypical antipsychotics clozapine and olanzapine promoted lysosomal sorting and reduced 5-HT7 receptor density (∼60% reduction within 24 h). Inhibition of lysosomal degradation with chloroquine blocked the clozapine- and olanzapine-induced down-regulation of 5-HT7 receptors. Incubation with SB269970 decreased both 5-HT7(b) constitutive internalization and receptor density but increased 5-HT7(d) receptor density, indicating differential ligand regulation among the 5-HT7 splice variants. CONCLUSIONS AND IMPLICATIONS Taken together, we found that various ligands differentially activate regulatory processes governing receptor internalization and degradation in addition to signal transduction. Thus, these data extend our understanding of functional selectivity at the 5-HT7 receptor.
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Affiliation(s)
- K W Andressen
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - O Manfra
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - C H Brevik
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - A H Ulsund
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - P Vanhoenacker
- Laboratory of Eukaryotic Gene Expression and Signal Transduction, Ghent University, Ghent, Belgium.,Intrexon ActoBiotics N.V., Technologiepark 4, Zwijnaarde, Belgium
| | - F O Levy
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - K A Krobert
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
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16
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Guseva D, Wirth A, Ponimaskin E. Cellular mechanisms of the 5-HT7 receptor-mediated signaling. Front Behav Neurosci 2014; 8:306. [PMID: 25324743 PMCID: PMC4181333 DOI: 10.3389/fnbeh.2014.00306] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 08/23/2014] [Indexed: 11/21/2022] Open
Abstract
Serotonin (5-hydroxytryptamine or 5-HT) is an important neurotransmitter regulating a wide range of physiological and pathological functions via activation of heterogeneously expressed 5-HT receptors. The 5-HT7 receptor is one of the most recently described members of the 5-HT receptor family. Functionally, 5-HT7 receptor is associated with a number of physiological and pathological responses, including serotonin-induced phase shifting of the circadian rhythm, control of memory as well as locomotor and exploratory activity. A large body of evidence indicates involvement of the 5-HT7 receptor in anxiety and depression, and recent studies suggest that 5-HT7 receptor can be highly relevant for the treatment of major depressive disorders. The 5-HT7 receptor is coupled to the stimulatory Gs-protein, and receptor stimulation results in activation of adenylyl cyclase (AC) leading to a rise of cAMP concentration. In addition, this receptor is coupled to the G12-protein to activate small GTPases of the Rho family. This review focuses on molecular mechanisms responsible for the 5-HT7 receptor-mediated signaling. We provide detailed overview of signaling cascades controlled and regulated by the 5-HT7 receptor and discuss the functional impact of 5-HT7 receptor for the regulation of different cellular and subcellular processes.
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Affiliation(s)
- Daria Guseva
- Department of Cellular Neurophysiology, Hannover Medical School Hannover, Germany
| | - Alexander Wirth
- Department of Cellular Neurophysiology, Hannover Medical School Hannover, Germany
| | - Evgeni Ponimaskin
- Department of Cellular Neurophysiology, Hannover Medical School Hannover, Germany
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17
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Meneses A. 5-HT systems: emergent targets for memory formation and memory alterations. Rev Neurosci 2014; 24:629-64. [PMID: 24259245 DOI: 10.1515/revneuro-2013-0026] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/29/2013] [Indexed: 12/20/2022]
Abstract
Drugs acting through 5-hydroxytryptamine (serotonin or 5-HT) systems modulate memory and its alterations, although the mechanisms involved are poorly understood. 5-HT drugs may present promnesic and/or antiamnesic (or even being amnesic) effects. Key questions regarding 5-HT markers include whether receptors directly or indirectly participate and/or contribute to the physiological and pharmacological basis of memory and its pathogenesis; hence, the major aim of this article was to examine recent advances in emergent targets of the 5-HT systems for memory formation and memory alterations. Recent reviews and findings are summarized, mainly in the context of the growing notion of memory deficits in brain disorders (e.g., posttraumatic stress disorder, mild cognitive impairment, consumption of drugs, poststroke cognitive dysfunctions, schizophrenia, Parkinson disease, and infection-induced memory impairments). Mainly, mammalian and (some) human data were the focus. At least agonists and antagonists for 5-HT1A/1B, 5-HT2A/2B/2C, 5-HT3, 5-HT4, 5-HT6, and 5-HT7 receptors as well as serotonin uptake inhibitors seem to have a promnesic and/or antiamnesic effect in different conditions and 5-HT markers seem to be associated to neural changes. Available evidence offers clues about the possibilities, but the exact mechanisms remain unclear. For instance, 5-HT transporter expression seems to be a reliable neural marker related to memory mechanisms and its alterations.
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18
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Guo D, Hillger JM, IJzerman AP, Heitman LH. Drug-Target Residence Time-A Case for G Protein-Coupled Receptors. Med Res Rev 2014; 34:856-92. [DOI: 10.1002/med.21307] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Dong Guo
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research; Leiden University; P.O. Box 9502 2300 RA Leiden the Netherlands
| | - Julia M. Hillger
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research; Leiden University; P.O. Box 9502 2300 RA Leiden the Netherlands
| | - Adriaan P. IJzerman
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research; Leiden University; P.O. Box 9502 2300 RA Leiden the Netherlands
| | - Laura H. Heitman
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research; Leiden University; P.O. Box 9502 2300 RA Leiden the Netherlands
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19
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Chue PS, MacKenzie EM, Chue JA, Baker GB. The pharmacology and formulation of paliperidone extended release. Expert Rev Neurother 2014; 12:1399-410. [DOI: 10.1586/ern.12.138] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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20
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Atanes P, Lacivita E, Rodríguez J, Brea J, Burgueño J, Vela JM, Cadavid MI, Loza MI, Leopoldo M, Castro M. The arylpiperazine derivatives N-(4-cyanophenylmethyl)-4-(2-diphenyl)-1-piperazinehexanamide and N-benzyl-4-(2-diphenyl)-1-piperazinehexanamide exert a long-lasting inhibition of human serotonin 5-HT7 receptor binding and cAMP signaling. Pharmacol Res Perspect 2013; 1:e00013. [PMID: 25505568 PMCID: PMC4186431 DOI: 10.1002/prp2.13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 09/15/2013] [Accepted: 09/24/2013] [Indexed: 12/16/2022] Open
Abstract
We performed a detailed in vitro pharmacological characterization of two arylpiperazine derivatives, compound N-(4-cyanophenylmethyl)-4-(2-diphenyl)-1-piperazinehexanamide (LP-211) previously identified as a high-affinity brain penetrant ligand for 5-hydroxytryptamine (serotonin) type 7 (5-HT7) receptors, and its analog N-benzyl-4-(2-diphenyl)-1-piperazinehexanamide (MEL-9). Both ligands exhibited competitive displacement of [3H]-(2R)-1-[(3-hydroxyphenyl)sulfonyl]-2-[2-(4-methyl-1-piperidinyl)ethyl]pyrrolidine ([3H]-SB-269970) radioligand binding and insurmountable antagonism of 5-carboxamidotryptamine (5-CT)-stimulated cyclic adenosine monophosphate (cAMP) signaling in human embryonic kidney (HEK293) cells stably expressing human 5-HT7 receptors. They also inhibited forskolin-stimulated adenylate cyclase activity in 5-HT7-expressing HEK293 cells but not in the parental cell line. The compounds elicited long-lasting (at least 24 h) concentration-dependent inhibition of radioligand binding at 5-HT7-binding sites in whole-cell radioligand binding assays, after pretreatment of the cells with the compounds and subsequent compound removal. In cAMP assays, pretreatment of cells with the compounds rendered 5-HT7 receptors unresponsive to 5-CT and also rendered 5-HT7-expressing HEK293 cells unresponsive to forskolin. Compound 1-(2-biphenyl)piperazine (RA-7), a known active metabolite of LP-211 present in vivo, was able to partially inhibit 5-HT7 radioligand binding in a long-lasting irreversible manner. Hence, LP-211 and MEL-9 were identified as high-affinity long-acting inhibitors of human 5-HT7 receptor binding and function in cell lines. The detailed in vitro characterization of these two pharmacological tools targeting 5-HT7 receptors may benefit the study of 5-HT7 receptor function and it may lead to the development of novel selective pharmacological tools with defined functional properties at 5-HT7 receptors.
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Affiliation(s)
- Patricio Atanes
- Biofarma Research Group, Department of Pharmacology, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela Santiago de Compostela, Spain
| | - Enza Lacivita
- Dipartimento di Farmacia - Scienze del Farmaco, Università degli Studi di Bari "A. Moro" Bari, Italy
| | - Javier Rodríguez
- Biofarma Research Group, Department of Pharmacology, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela Santiago de Compostela, Spain
| | - José Brea
- Biofarma Research Group, Department of Pharmacology, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela Santiago de Compostela, Spain
| | - Javier Burgueño
- Esteve; Drug Discovery and Preclinical Development Barcelona, Spain
| | - José Miguel Vela
- Esteve; Drug Discovery and Preclinical Development Barcelona, Spain
| | - María Isabel Cadavid
- Biofarma Research Group, Department of Pharmacology, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela Santiago de Compostela, Spain
| | - María Isabel Loza
- Biofarma Research Group, Department of Pharmacology, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela Santiago de Compostela, Spain
| | - Marcello Leopoldo
- Dipartimento di Farmacia - Scienze del Farmaco, Università degli Studi di Bari "A. Moro" Bari, Italy
| | - Marián Castro
- Biofarma Research Group, Department of Pharmacology, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela Santiago de Compostela, Spain
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21
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The serotonin 5-HT7 receptors: two decades of research. Exp Brain Res 2013; 230:555-68. [PMID: 24042216 DOI: 10.1007/s00221-013-3694-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 08/26/2013] [Indexed: 01/12/2023]
Abstract
Like most neurotransmitters, serotonin possesses a simple structure. However, the pharmacological consequences are more complex and diverse. Serotonin is involved in numerous functions in the human body including the control of appetite, sleep, memory and learning, temperature regulation, mood, behavior, cardiovascular function, muscle contraction, endocrine regulation, and depression. Low levels of serotonin may be associated with several disorders, namely increase in aggressive and angry behaviors, clinical depression, Parkinson's disease, obsessive-compulsive disorder, eating disorders, migraine, irritable bowel syndrome, tinnitus, and bipolar disease. These effects are mediated via different serotonin (5-HT) receptors. In this review, we will focus on the last discovered member of this serotonin receptor family, the 5-HT7 receptor. This receptor belongs to the G protein-coupled receptor superfamily and was cloned two decades ago. Later, different splice variants were described but no major functional differences have been described so far. All 5-HT7 receptor variants are coupled to Gαs proteins and stimulate cAMP formation. Recently, several interacting proteins have been reported, which can influence receptor signaling and trafficking.
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22
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Wu-Wong JR, Nakane M, Chen YW, Mizobuchi M. Mechanistic analysis for time-dependent effects of cinacalcet on serum calcium, phosphorus, and parathyroid hormone levels in 5/6 nephrectomized rats. Physiol Rep 2013; 1:e00046. [PMID: 24303131 PMCID: PMC3835002 DOI: 10.1002/phy2.46] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 07/05/2013] [Accepted: 07/08/2013] [Indexed: 12/21/2022] Open
Abstract
This study investigates the time-dependent effects of cinacalcet on serum calcium, phosphorus, and parathyroid hormone (PTH) levels in 5/6 nephrectomized (NX) rats with experimental chronic renal insufficiency. In this study, 5/6 NX male, Sprague-Dawley rats were treated with vehicle or cinacalcet (10 mg/kg, oral, 1× daily). On Day 0 (before treatment), Day 12 and 13 after treatment (to approximate the clinical practice), and also at 0, 1, 4, 8, 16, and 24 hours after the last dosing, blood was collected for analysis. After 12 or 13 days of cinacalcet treatment, modest changes were observed in serum Ca and phosphorus (Pi), while PTH decreased by >45% to Sham levels (152 ± 15 pg/mL). Detailed mapping found that cinacalcet caused a significant time-dependent decrease in serum Ca following dosing, reaching a lowest point at 8 hours (decrease by 20% to 8.43 ± 0.37 mg/dL), and then returning to normal at 24 hours. Cinacalcet also caused a significant increase in serum Pi levels (by 18%). To investigate the potential mechanism of action, a broad approach was taken by testing cinacalcet in a panel of 77 protein-binding assays. Cinacalcet interacted with several channels, transporters, and neurotransmitter receptors, some of which are involved in brain and heart, and may impact Ca homeostasis. Cinacalcet dose-dependently increased brain natriuretic peptide (BNP) mRNA expression by 48% in cardiomyocytes, but had no significant effects on left ventricular hypertrophy and cardiac function. The results suggest that cinacalcet's hypocalcemic effect may be due to its nonspecific interaction with other receptors in brain and heart.
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Affiliation(s)
- J Ruth Wu-Wong
- Department of Pharmacy Practice, University of Illinois at Chicago Chicago, Illinois
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23
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Herth MM, Volk B, Pallagi K, Kofoed Bech L, Antoni FA, Knudsen GM, Kristensen JL. Synthesis and in vitro evaluation of oxindole derivatives as potential radioligands for 5-HT(7) receptor imaging with PET. ACS Chem Neurosci 2012; 3:1002-7. [PMID: 23259035 DOI: 10.1021/cn3001137] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 08/31/2012] [Indexed: 01/15/2023] Open
Abstract
The most recently discovered serotonin (5-HT) receptor subtype, 5-HT(7), is considered to be associated with several CNS disorders. Noninvasive in vivo positron emission tomography (PET) studies of cerebral 5-HT(7) receptors could provide a significant advance in the understanding of the neurobiology and eventual dysfunctions of the 5-HT(7) receptor. To date, no appropriate 5-HT(7) receptor PET ligand has been developed. Here, we modified known 5-HT(7) selective phenylpiperazinyl-butyloxindole derivatives so that they may be labeled either with carbon-11 or fluorine-18. A set of potential 5-HT(7) ligands for PET molecular imaging was successfully synthesized. Two compounds (10 and 14) were tested against a range of targets. Both compounds display a promising in vitro profile with respect to PET imaging of the 5-HT(7) receptor in thalamic regions.
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Affiliation(s)
- Matthias M. Herth
- Center for Integrated Molecular Brain
Imaging, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, DK-2100
Copenhagen, Denmark
- Department
of Drug Design and
Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100
Copenhagen, Denmark
| | - Balázs Volk
- Chemical
Research Division, Egis Pharmaceuticals Plc., P.O. Box 100, H-1475 Budapest,
Hungary
| | - Katalin Pallagi
- Division of Preclinical
Research, Egis Pharmaceuticals Plc., P.O.
Box 100, H-1475 Budapest,
Hungary
| | - Lasse Kofoed Bech
- Center for Integrated Molecular Brain
Imaging, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, DK-2100
Copenhagen, Denmark
| | - Ferenc A. Antoni
- Division of Preclinical
Research, Egis Pharmaceuticals Plc., P.O.
Box 100, H-1475 Budapest,
Hungary
| | - Gitte M. Knudsen
- Center for Integrated Molecular Brain
Imaging, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, DK-2100
Copenhagen, Denmark
| | - Jesper L. Kristensen
- Center for Integrated Molecular Brain
Imaging, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, DK-2100
Copenhagen, Denmark
- Department
of Drug Design and
Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100
Copenhagen, Denmark
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Tokarski K, Zelek-Molik A, Duszyńska B, Satała G, Bobula B, Kusek M, Chmielarz P, Nalepa I, Hess G. Acute and repeated treatment with the 5-HT7 receptor antagonist SB 269970 induces functional desensitization of 5-HT7 receptors in rat hippocampus. Pharmacol Rep 2012; 64:256-65. [PMID: 22661174 DOI: 10.1016/s1734-1140(12)70763-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 03/22/2012] [Indexed: 01/01/2023]
Abstract
BACKGROUND SB 269970, a 5-HT(7) receptor antagonist may produce a faster antidepressant-like effect in animal models, than do antidepressant drugs, e.g., imipramine. The present work was aimed at examining the effect of single and repeated (14 days) administration of SB 269970 on the 5-HT(7) receptor in the hippocampus. METHODS The reactivity of 5-HT(7) receptors was determined using 5-carboxamidotryptamine (5-CT), which increased the bursting frequency of spontaneous epileptiform activity in hippocampal slices. Additionally, the effects of SB 269970 administration on the affinity and density of 5-HT(7) receptors were investigated using [(3)H]-SB 269970 and the influence of SB 269970 and imipramine on mRNA expression levels of Gα(s) and Gα(12) mRNA were studied using RT-qPCR. RESULTS Acute and repeated treatment with SB 269970 led to attenuation of the excitatory effects of activation of 5-HT(7) receptors. Neither single nor repeated administration of SB 269970 changed the mean affinity of 5-HT(7) receptors for [(3)H]-SB 269970. Repeated, but not single, administration of SB 269970 decreased the maximum density of [(3)H]-SB 269970 binding sites. While administration of imipramine did not change the expression of mRNAs for Gα(s) and Gα(12) proteins after both single and repeated administration of SB 269970, a reduction in Gα(s) and Gα(12) mRNA expression levels was evident. CONCLUSIONS These findings indicate that even single administration of SB269970 induces functional desensitization of the 5-HT(7) receptor system, which precedes changes in the receptor density. This mechanism may be responsible for the rapid antidepressant-like effect of the 5-HT(7) antagonist in animal models.
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Affiliation(s)
- Krzysztof Tokarski
- Department of Physiology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, PL 31-343 Kraków, Poland.
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25
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Vauquelin G, Van Liefde I. Radioligand dissociation measurements: potential interference of rebinding and allosteric mechanisms and physiological relevance of the biological model systems. Expert Opin Drug Discov 2012; 7:583-95. [DOI: 10.1517/17460441.2012.687720] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Herth MM, Hansen HD, Ettrup A, Dyssegaard A, Lehel S, Kristensen J, Knudsen GM. Synthesis and evaluation of [¹¹C]Cimbi-806 as a potential PET ligand for 5-HT₇ receptor imaging. Bioorg Med Chem 2012; 20:4574-81. [PMID: 22682922 DOI: 10.1016/j.bmc.2012.05.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 04/06/2012] [Accepted: 05/03/2012] [Indexed: 01/24/2023]
Abstract
2-(2',6'-Dimethoxy-[1,1'-biphenyl]-3-yl)-N,N-dimethylethanamine has been identified as a potent ligand for the serotonin 7 (5-HT(7)) receptor. In this study, we describe the synthesis, radiolabeling and in vivo evaluation of [(11)C]2-(2',6'-dimethoxy-[1,1'-biphenyl]-3-yl)-N,N-dimethylethanamine ([(11)C]Cimbi-806) as a radioligand for imaging brain 5-HT(7) receptors with positron emission tomography (PET). Precursor and reference compound was synthesized and subsequent (11)C-labelling with [(11)C]methyltriflate produced [(11)C]Cimbi-806 in specific activities ranging from 50 to 300 GBq/μmol. Following intravenous injection, brain uptake and distribution of [(11)C]Cimbi-806 was assessed with PET in Danish Landrace pigs. The time-activity curves revealed high brain uptake in thalamic and striatal regions (SUV ∼2.5) and kinetic modeling resulted in distribution volumes (V(T)) ranging from 6 mL/cm(3) in the cerebellum to 12 mL/cm(3) in the thalamus. Pretreatment with the 5-HT(7) receptor antagonist SB-269970 did not result in any significant changes in [(11)C]Cimbi-806 binding in any of the analyzed regions. Despite the high brain uptake and relevant distribution pattern, the absence of appropriate in vivo blocking with a 5-HT(7) receptor selective compounds renders the conclusion that [(11)C]Cimbi-806 is not an appropriate PET radioligand for imaging the 5-HT(7) receptor in vivo.
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Affiliation(s)
- Matthias M Herth
- Center for Integrated Molecular Brain Imaging, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
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Characterization of α2B-adrenoceptor ligand binding in the presence of Muscarinic toxin α and delineation of structural features of receptor binding selectivity. Eur J Pharmacol 2012; 683:63-70. [DOI: 10.1016/j.ejphar.2012.03.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 03/09/2012] [Accepted: 03/09/2012] [Indexed: 11/24/2022]
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Vauquelin G, Bostoen S, Vanderheyden P, Seeman P. Clozapine, atypical antipsychotics, and the benefits of fast-off D2 dopamine receptor antagonism. Naunyn Schmiedebergs Arch Pharmacol 2012; 385:337-72. [PMID: 22331262 DOI: 10.1007/s00210-012-0734-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 01/25/2012] [Indexed: 12/20/2022]
Abstract
Drug-receptor interactions are traditionally quantified in terms of affinity and efficacy, but there is increasing awareness that the drug-on-receptor residence time also affects clinical performance. While most interest has hitherto been focused on slow-dissociating drugs, D(2) dopamine receptor antagonists show less extrapyramidal side effects but still have excellent antipsychotic activity when they dissociate swiftly. Fast dissociation of clozapine, the prototype of the "atypical antipsychotics", has been evidenced by distinct radioligand binding approaches both on cell membranes and intact cells. The surmountable nature of clozapine in functional assays with fast-emerging responses like calcium transients is confirmatory. Potential advantages and pitfalls of the hitherto used techniques are discussed, and recommendations are given to obtain more precise dissociation rates for such drugs. Surmountable antagonism is necessary to allow sufficient D(2) receptor stimulation by endogenous dopamine in the striatum. Simulations are presented to find out whether this can be achieved during sub-second bursts in dopamine concentration or rather during much slower, activity-related increases thereof. While the antagonist's dissociation rate is important to distinguish between both mechanisms, this becomes much less so when contemplating time intervals between successive drug intakes, i.e., when pharmacokinetic considerations prevail. Attention is also drawn to the divergent residence times of hydrophobic antagonists like haloperidol when comparing radioligand binding data on cell membranes with those on intact cells and clinical data.
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Affiliation(s)
- Georges Vauquelin
- Department of Molecular and Biochemical Pharmacology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
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Vauquelin G. Determination of drug–receptor residence times by radioligand binding and functional assays: experimental strategies and physiological relevance. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md20015e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Teitler M, Klein MT. A new approach for studying GPCR dimers: drug-induced inactivation and reactivation to reveal GPCR dimer function in vitro, in primary culture, and in vivo. Pharmacol Ther 2011; 133:205-17. [PMID: 22119169 DOI: 10.1016/j.pharmthera.2011.10.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 10/29/2011] [Indexed: 12/28/2022]
Abstract
GPCRs are a major family of homologous proteins and are key mediators of the effects of numerous endogenous neurotransmitters, hormones, cytokines, therapeutic drugs, and drugs-of-abuse. Despite the enormous amount of research on the pharmacological and biochemical properties of GPCRs, the question as to whether they exist as monomers, dimers, or higher order structures in the body is unanswered. The GPCR dimer field has been dominated by techniques involving recombinant cell lines expressing mutant receptors, often involving the solubilization of the receptors. These techniques cannot be applied in vivo or even to primary cell cultures. This review will focus on a novel approach to exploring the functional properties of homodimers. Studies of the 5-HT(7) and 5-HT(2A) serotonin receptors have revealed that binding of a pseudo-irreversible antagonist ("inactivator") to one of the orthosteric sites of a homodimer abolishes all receptor activity, and subsequent binding of a competitive antagonist to the orthosteric site of the second protomer releases the inactivator, allowing the receptor to return to an active state. This approach demonstrates allosteric crosstalk between protomers of native GPCR homodimers, indicating that GPCRs do exist and function as homodimers in both recombinant cells and rat primary astrocytes. This technique can be applied universally using intact recombinant or primary cells in culture, membrane homogenate preparations and, potentially, in vivo. The data obtained using the 5-HT(7) and 5-HT(2A) receptors are strongly supportive of a GPCR homodimer structure, with little evidence of monomer involvement in the function of these receptors.
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Affiliation(s)
- Milt Teitler
- Center for Neuropharmacology & Neuroscience, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA.
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Packeu A, Wennerberg M, Balendran A, Vauquelin G. Estimation of the dissociation rate of unlabelled ligand-receptor complexes by a 'two-step' competition binding approach. Br J Pharmacol 2011; 161:1311-28. [PMID: 20946109 DOI: 10.1111/j.1476-5381.2010.00931.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Because the in vivo effectiveness of ligands may also be determined by the rate by which they dissociate from their target receptors, drug candidates are being increasingly screened for this kinetic property. The dissociation rate of unlabelled ligand-receptor complexes can be estimated indirectly from their ability to slow the association of subsequently added radioligand molecules. EXPERIMENTAL APPROACH We used the 'two-step competition' binding approach consisting of pre-incubating the receptor preparation with a wide range of ligand concentrations, washing off free ligand molecules, adding radioligand and monitoring its receptor binding after a fixed time. Based on the rationale that binding of both ligands is mutually exclusive and that they bind according to the law of mass action to a single class of sites, the unlabelled ligand's dissociation rate can be estimated from the upward shift that the competition curve experiences after washing. KEY RESULTS The relevance of the 'two-step competition' approach was explored by computer simulations and by comparing the dissociation behaviour of unlabelled D(2) dopamine and CB(1) cannabinoid receptor antagonists in this and alternative approaches. Besides providing satisfactory estimations of dissociation rates, the method also detects the ability of the unlabelled ligand molecules to be released from 'sinks' such as the cell membrane. CONCLUSIONS AND IMPLICATIONS As the 'two-step competition' requires rapid intermediate washing steps and needs radioligand binding to be measured at only one time point, this approach is particularly suited for binding studies on intact plated cells. LINKED ARTICLES This article is part of a themed section on Analytical Receptor Pharmacology in Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2010.161.issue-6.
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Affiliation(s)
- A Packeu
- Department of Molecular and Biochemical Pharmacology, Free University of Brussels (VUB), Brussels, Belgium
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Klein MT, Teitler M. Antagonist interaction with the human 5-HT(7) receptor mediates the rapid and potent inhibition of non-G-protein-stimulated adenylate cyclase activity: a novel GPCR effect. Br J Pharmacol 2011; 162:1843-54. [PMID: 21198551 PMCID: PMC3081126 DOI: 10.1111/j.1476-5381.2010.01194.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 11/02/2010] [Accepted: 12/06/2010] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The human 5-hydroxytryptamine(7) (h5-HT(7)) receptor is G(s) -coupled and stimulates the production of the intracellular signalling molecule cAMP. Previously, we reported a novel property of the h5-HT(7) receptor: pseudo-irreversible antagonists irreversibly inhibit forskolin-stimulated (non-receptor-mediated) cAMP production. Herein, we sought to determine if competitive antagonists also affect forskolin-stimulated activity and if this effect is common among other G(s) -coupled receptors. EXPERIMENTAL APPROACH Recombinant cell lines expressing h5-HT(7) receptors or other receptors of interest were briefly exposed to antagonists; cAMP production was then stimulated by forskolin and quantified by an immunocompetitive assay. KEY RESULTS In human embryonic kidney 293 cells stably expressing h5-HT(7) receptors, all competitive antagonists inhibited nearly 100% of forskolin-stimulated cAMP production. This effect was insensitive to pertussis toxin, that is, not G(i/o) -mediated. Potency to inhibit forskolin-stimulated activity strongly correlated with h5-HT(7) binding affinity (r(2) = 0.91), indicating that the antagonists acted through h5-HT(7) receptors to inhibit forskolin. Potency and maximal effects of clozapine, a prototypical competitive h5-HT(7) antagonist, were unaffected by varying forskolin concentration. Antagonist interaction with h5-HT(6), human β(1), β(2), and β(3) adrenoceptors did not inhibit forskolin's activity. CONCLUSIONS AND IMPLICATIONS The inhibition of adenylate cyclase, as measured by forskolin's activity, is an underlying property of antagonist interaction with h5-HT(7) receptors; however, this is not a common property of other G(s) -coupled receptors. This phenomenon may be involved in the roles played by h5-HT(7) receptors in human physiology. Development of h5-HT(7) antagonists that do not elicit this effect would aid in the elucidation of its mechanisms and shed light on its possible physiological relevance.
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Affiliation(s)
- M T Klein
- Albany Medical College, Center for Neuropharmacology & Neuroscience, 47 New Scotland Avenue, MC 136, Albany, NY 12208, USA
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Matthys A, Haegeman G, Van Craenenbroeck K, Vanhoenacker P. Role of the 5-HT7 receptor in the central nervous system: from current status to future perspectives. Mol Neurobiol 2011; 43:228-53. [PMID: 21424680 DOI: 10.1007/s12035-011-8175-3] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 03/01/2011] [Indexed: 12/11/2022]
Abstract
Pharmacological and genetic tools targeting the 5-hydroxytryptamine (5-HT)7 receptor in preclinical animal models have implicated this receptor in diverse (patho)physiological processes of the central nervous system (CNS). Some data obtained with 5-HT7 receptor knockout mice, selective antagonists, and, to a lesser extent, agonists, however, are quite contradictory. In this review, we not only discuss in detail the role of the 5-HT7 receptor in the CNS but also propose some hypothetical models, which could explain the observed inconsistencies. These models are based on two novel concepts within the field of G protein-coupled receptors (GPCR), namely biphasic signaling and G protein-independent signaling, which both have been shown to be mediated by GPCR dimerization. This led us to suggest that the 5-HT7 receptor could reside in different dimeric contexts and initiate different signaling pathways, depending on the neuronal circuitry and/or brain region. In conclusion, we highlight GPCR dimerization and G protein-independent signaling as two promising future directions in 5-HT7 receptor research, which ultimately might lead to the development of more efficient dimer- and/or pathway-specific therapeutics.
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Affiliation(s)
- Anne Matthys
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Department of Physiology, Ghent University (UGent), Ghent, Belgium
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Kast RE. Glioblastoma chemotherapy adjunct via potent serotonin receptor-7 inhibition using currently marketed high-affinity antipsychotic medicines. Br J Pharmacol 2011; 161:481-7. [PMID: 20880389 DOI: 10.1111/j.1476-5381.2010.00923.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Glioblastoma treatment as now constituted offers increased survival measured in months over untreated patients. Because glioblastomas are active in synthesizing a bewildering variety of growth factors, a systematic approach to inhibiting these is being undertaken as treatment adjunct. The serotonin 7 receptor is commonly overexpressed in glioblastoma. Research documentation showing agonists at serotonin receptor 7 cause increased extracellular regulated kinase 1/2 activation, increased interleukin-6 synthesis, increased signal transducer and activator of transcription-3 activation, increased resistance to apoptosis and other growth enhancing changes in glioblastoma is reviewed in this paper. Because three drugs in wide use to treat thought disorders - paliperidone, pimozide and risperidone - are also potent and well-tolerated inhibitors at serotonin receptor 7, these drugs should be studied for growth factor deprivation in an adjunctive role in glioblastoma treatment.
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Affiliation(s)
- R E Kast
- Department of Psychiatry, University of Vermont, Burlington, VT, USA.
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Celikyurt IK, Akar FY, Ulak G, Mutlu O, Erden F. Effects of Risperidone on Learning and Memory in Naive and MK-801-Treated Rats. Pharmacology 2011; 87:187-94. [DOI: 10.1159/000324523] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 01/18/2011] [Indexed: 11/19/2022]
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Teitler M, Toohey N, Knight JA, Klein MT, Smith C. Clozapine and other competitive antagonists reactivate risperidone-inactivated h5-HT7 receptors: radioligand binding and functional evidence for GPCR homodimer protomer interactions. Psychopharmacology (Berl) 2010; 212:687-97. [PMID: 20827463 PMCID: PMC3052287 DOI: 10.1007/s00213-010-2001-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 08/13/2010] [Indexed: 11/30/2022]
Abstract
RATIONALE The h5-HT(7) receptor is subject to inactivation by risperidone and 9-OH-risperidone, apparently through a pseudo-irreversible complex formed between these drugs and the receptor. Although risperidone and 9-OH-risperidone ("inactivating antagonists") completely inactivate the receptor, only 50% of the receptors form a pseudo-irreversible complex with these drugs. OBJECTIVES This study aims to more fully determine the mechanism(s) responsible for the novel effects of risperidone and 9-OH-risperidone and to determine if the inactivation can be reversed (reactivation). METHODS The ability of non-inactivating drugs (competitive antagonists) to dissociate wash-resistant [(3)H]risperidone binding from h5-HT(7) receptors was investigated. Also, the ability of non-inactivating drugs to reactivate inactivated h5-HT(7) receptors was investigated, using cAMP accumulation as a functional endpoint. RESULTS The competitive (non-inactivating) antagonists clozapine and mesulergine released the wash-resistant [(3)H]risperidone binding to the h5-HT(7) receptor. The competitive antagonists clozapine, SB269970, mianserin, cyproheptadine, mesulergine, and ICI169369 reactivated the risperidone-inactivated h5-HT(7) receptors in a concentration-dependent manner. The potencies for reactivation closely match the affinities of these drugs for the h5-HT(7) receptor (r(2) = 0.95), indicating that the reactivating antagonists are binding to and producing their effects through the orthosteric binding site of the h5-HT(7) receptor. Bioluminescence resonance energy transfer analyses indicate that the h5-HT(7) receptor forms homodimers. CONCLUSIONS The ability of the non-inactivating drugs to bind h5-HT(7) orthosteric sites and reverse the wash-resistant effects of risperidone or 9-OH-risperidone, also bound to h5-HT(7) orthosteric sites, is evidence for protomer-protomer interactions between h5-HT(7) homodimers. This is the first demonstration of a non-mutated G-protein-coupled receptor homodimer engaging in protomer-protomer interactions in an intact cell preparation.
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Affiliation(s)
- Milt Teitler
- Center for Neuropharmacology & Neuroscience, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA.
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Seyrek M, Kahraman S, Deveci MS, Yesilyurt O, Dogrul A. Systemic cannabinoids produce CB1-mediated antinociception by activation of descending serotonergic pathways that act upon spinal 5-HT7 and 5-HT2A receptors. Eur J Pharmacol 2010; 649:183-94. [DOI: 10.1016/j.ejphar.2010.09.039] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 07/24/2010] [Accepted: 09/14/2010] [Indexed: 12/27/2022]
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Smith C, Toohey N, Knight JA, Klein MT, Teitler M. Risperidone-induced inactivation and clozapine-induced reactivation of rat cortical astrocyte 5-hydroxytryptamine₇ receptors: evidence for in situ G protein-coupled receptor homodimer protomer cross-talk. Mol Pharmacol 2010; 79:318-25. [PMID: 21062995 DOI: 10.1124/mol.110.069278] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have reported previously novel drug-induced inactivation and reactivation of human 5-hydroxytryptamine₇ (5-HT₇) receptors in a recombinant cell line. To explain these novel observations, a homodimer structure displaying protomer-protomer cross-talk was proposed. To determine whether these novel observations and interpretations are due to an artifactual G protein-coupled receptor (GPCR) mechanism unique to the recombinant cell line, we explored the properties of r5-HT₇ receptors expressed by cortical astrocytes in primary culture. As in the recombinant cell line, risperidone, 9-OH-risperidone, methiothepin, and bromocriptine were found to potently inactivate r5-HT₇ receptors. As in the recombinant cell line, exposure of risperidone-inactivated astrocyte r5-HT₇ receptors to competitive antagonists resulted in the reactivation of r5-HT₇ receptors. The potencies of the reactivating drugs closely correlated with their affinities for h5-HT₇ receptors. These results indicate the novel inactivating and reactivating property of drugs is not due to an artifact of the recombinant cell line expressing h5-HT₇ receptors but is an intrinsic property of 5-HT₇ receptors in vitro and ex vivo. This evidence suggests that a native (nonmutated) GPCR, in its native membrane environment (cortical astrocyte primary culture), can function as a homodimer with protomer-protomer cross-talk. Homodimers may be a common GPCR structure. The experimental design used in our studies can be used to explore the properties of other GPCRs in their native forms in recombinant cells, primary cultures expressing the endogenous GPCRs, and possibly in vivo. The homodimer structure and protomer-protomer cross-talk offer new avenues of research into receptor dysfunction in disease states and the development of novel drugs.
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Affiliation(s)
- Carol Smith
- Center for Neuropharmacology and Neuroscience, Albany Medical College, 47 New Scotland Ave., Albany, NY 12208, USA
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Ligand-directed c-Jun N-terminal kinase activation disrupts opioid receptor signaling. Proc Natl Acad Sci U S A 2010; 107:11608-13. [PMID: 20534436 DOI: 10.1073/pnas.1000751107] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Ligand-directed signaling has been suggested as a basis for the differences in responses evoked by otherwise receptor-selective agonists. The underlying mechanisms are not understood, yet clearer definition of this concept may be helpful in the development of novel, pathway-selective therapeutic agents. We previously showed that kappa-opioid receptor activation of JNK by one class of ligand, but not another, caused persistent receptor inactivation. In the current study, we found that the mu-opioid receptor (MOR) could be similarly inactivated by a specific ligand class including the prototypical opioid, morphine. Acute analgesic tolerance to morphine and related opioids (morphine-6-glucuronide and buprenorphine) was blocked by JNK inhibition, but not by G protein receptor kinase 3 knockout. In contrast, a second class of mu-opioids including fentanyl, methadone, and oxycodone produced acute analgesic tolerance that was blocked by G protein receptor kinase 3 knockout, but not by JNK inhibition. Acute MOR desensitization, demonstrated by reduced D-Ala(2)-Met(5)-Glyol-enkephalin-stimulated [(35)S]GTPgammaS binding to spinal cord membranes from morphine-pretreated mice, was also blocked by JNK inhibition; however, desensitization of D-Ala(2)-Met(5)-Glyol-enkephalin-stimulated [(35)S]GTPgammaS binding following fentanyl pretreatment was not blocked by JNK inhibition. JNK-mediated receptor inactivation of the kappa-opioid receptor was evident in both agonist-stimulated [(35)S]GTPgammaS binding and opioid analgesic assays; however, gene knockout of JNK 1 selectively blocked kappa-receptor inactivation, whereas deletion of JNK 2 selectively blocked MOR inactivation. These findings suggest that ligand-directed activation of JNK kinases may generally provides an alternate mode of G protein-coupled receptor regulation.
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Bruchas MR, Chavkin C. Kinase cascades and ligand-directed signaling at the kappa opioid receptor. Psychopharmacology (Berl) 2010; 210:137-47. [PMID: 20401607 PMCID: PMC3671863 DOI: 10.1007/s00213-010-1806-y] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2009] [Accepted: 02/15/2010] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND RATIONALE The dynorphin/kappa opioid receptor (KOR) system has been implicated as a critical component of the stress response. Stress-induced activation of dynorphin-KOR is well known to produce analgesia, and more recently, it has been implicated as a mediator of stress-induced responses including anxiety, depression, and reinstatement of drug seeking. OBJECTIVE Drugs selectively targeting specific KOR signaling pathways may prove potentially useful as therapeutic treatments for mood and addiction disorders. RESULTS KOR is a member of the seven transmembrane spanning (7TM) G-protein coupled receptor (GPCR) superfamily. KOR activation of pertussis toxin-sensitive G proteins leads to Galphai/o inhibition of adenylyl cyclase production of cAMP and releases Gbetagamma, which modulates the conductances of Ca(+2) and K(+) channels. In addition, KOR agonists activate kinase cascades including G-protein coupled Receptor Kinases (GRK) and members of the mitogen-activated protein kinase (MAPK) family: ERK1/2, p38 and JNK. Recent pharmacological data suggests that GPCRs exist as dynamic, multi-conformational protein complexes that can be directed by specific ligands towards distinct signaling pathways. Ligand-induced conformations of KOR that evoke beta-arrestin-dependent p38 MAPK activation result in aversion; whereas ligand-induced conformations that activate JNK without activating arrestin produce long-lasting inactivation of KOR signaling. CONCLUSIONS In this review, we discuss the current status of KOR signal transduction research and the data that support two novel hypotheses: (1) KOR selective partial agonists that do not efficiently activate p38 MAPK may be useful analgesics without producing the dysphoric or hallucinogenic effects of selective, highly efficacious KOR agonists and (2) KOR antagonists that do not activate JNK may be effective short-acting drugs that may promote stress-resilience.
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Affiliation(s)
- Michael R Bruchas
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
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Abstract
Ligand-receptor interactions are customarily described by equations that apply to solutes. Yet, most receptors are present in cell membranes so that sufficiently lipophilic ligands could reach the receptor by a two-dimensional approach within the membrane. As summarized in this review, this may affect the ligand-receptor interaction in many ways. Biophysicians calculated that, compared to a three-dimensional approach from the liquid phase, such approach could alter the time the ligands need to find a receptor. Biochemists found that ligand incorporation in lipid bilayers modifies their conformation. This, along with the depth at which the ligands reside in the bilayer, will affect the probability of successful receptor interaction. Novel mechanisms were also introduced, including "exosite" binding and ligand translocation between the receptor's alpha-helical transmembrane domains. Pharmacologists focused attention at ligand concentrations in membrane, their adsorption and release rates and the effects thereof on ligand potency and residence time at the receptor.
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Affiliation(s)
- G Vauquelin
- Department of Molecular and Biochemical Pharmacology, Institute for Molecular Biology and Biotechnology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium.
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Wennerberg M, Balendran A, Clapham JC, Vauquelin G. Unravelling the complex dissociation of [(3)H]-rimonabant from plated CB(1) cannabinoid receptor-expressing cells. Fundam Clin Pharmacol 2009; 24:181-7. [PMID: 19702692 DOI: 10.1111/j.1472-8206.2009.00756.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dissociation profile of the antagonist [(3)H]-rimonabant from recombinant CB(1) cannabinoid receptors expressed in plated HEK293 cells followed a complex pattern when measured in medium only. After a rapid decline, the specific binding levelled off at about 20% below the initial value. To unravel the responsible mechanism(s), we examined the relative contribution of binding to cells and walls of the culture wells respectively. Washout was also performed in the presence of an excess of unlabelled ligand and/or bovine serum albumin (BSA). The findings suggest that dissociated [(3)H]-rimonabant molecules not only undergo rebinding to the same or neighbouring receptors but also partition in the cell membranes and fix to the walls. As these non-receptor associations still occur in presence of unlabelled ligand, they can be erroneously regarded to represent 'specific binding'. While the unlabelled ligand was most effective in preventing receptor rebinding, BSA was most effective in preventing non-receptor associations. To measure receptor-dissociation only, washout is best performed in presence of unlabelled ligand and BSA or any other protein that can pick-up free radioligand molecules. Yet, washout in medium only could hint at mechanisms that affect the in vivo residence time of the drug in question.
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Toohey N, Klein MT, Knight J, Smith C, Teitler M. Human 5-HT7 receptor-induced inactivation of forskolin-stimulated adenylate cyclase by risperidone, 9-OH-risperidone and other "inactivating antagonists". Mol Pharmacol 2009; 76:552-9. [PMID: 19509219 DOI: 10.1124/mol.109.056283] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have previously reported on the unusual human 5-hydroxytryptamine(7) (h5-HT(7)) receptor-inactivating properties of risperidone, 9-OH-risperidone, bromocriptine, methiothepin, metergoline, and lisuride. Inactivation was defined as the inability of 10 microM 5-HT to stimulate cAMP accumulation after brief exposure and thorough removal of the drugs from HEK293 cells expressing h5-HT(7) receptors. Herein we report that brief exposure of the h5-HT(7) receptor-expressing cells to inactivating drugs, followed by removal of the drugs, results in potent and efficacious irreversible inhibition of forskolin-stimulated adenylate cyclase activity. Pretreatment, followed by removal of the inactivating drugs inhibited 10 microM forskolin-stimulated adenylate cyclase activity with potencies similar to the drugs' affinities for the h5-HT(7) receptor. The actions of the inactivating drugs were pertussis toxin-insensitive, indicating the lack of G(i) in their mechanism(s) of action. Methiothepin and bromocriptine maximally inhibited 10 microM forskolin-stimulated adenylate cyclase, whereas the other drugs produced partial inhibition, indicating the drugs are inducing slightly different inactive conformations of the h5-HT(7) receptor. Maximal effects of these inactivating drugs occurred within 15 to 30 min of exposure of the cells to the drugs. A G(s)-mediated inhibition of forskolin-stimulated activity has never been reported. The inactivating antagonists seem to induce a stable conformation of the h5-HT(7) receptor, which induces an altered state of G(s), which, in turn, inhibits forskolin-mediated stimulation of adenylate cyclase. These and previous observations indicate that the inactivating antagonists represent a unique class of drugs and may reveal GPCR regulatory mechanisms previously unknown. These drugs may produce innovative approaches to the development of therapeutic drugs.
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Affiliation(s)
- Nicole Toohey
- Center for Neuropharmacology and Neuroscience, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA
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Wei Z, Wang L, Xuan J, Che R, Du J, Qin S, Xing Y, Gu B, Yang L, Li H, Li J, Feng G, He L, Xing Q. Association analysis of serotonin receptor 7 gene (HTR7) and risperidone response in Chinese schizophrenia patients. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:547-51. [PMID: 19233240 DOI: 10.1016/j.pnpbp.2009.02.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 02/08/2009] [Accepted: 02/12/2009] [Indexed: 01/05/2023]
Abstract
Several lines of evidence suggest that the human 5-HT(7) receptor may be involved in the pharmacodynamics of risperidone and may influence clinical response of the drug. A pharmocogenetics study of this receptor may therefore be useful in developing individualized therapy. But few studies about it have been done. In this study, we genotyped ten single nucleotide polymorphisms (SNPs) distributed throughout the HTR7 gene and analyzed six of them for association with the reduction of Brief Psychiatric Rating Scale (BPRS) scores in drug-naive Chinese schizophrenia patients, following an eight-week period of risperidone monotherapy. The confounding effects of nongenetic factors were estimated and the baseline symptom score as well as the duration of illness were included as covariates for adjustment. No significant correlation of HTR7 with antipsychotic efficacy was detected in either genotype or haplotype analysis. These results demonstrate that variations in the HTR7 gene may not be good genetic markers for predicting the therapeutic efficacy of risperidone.
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Affiliation(s)
- Zhiyun Wei
- Bio-X Center, Shanghai Jiao Tong University, Shanghai 200030, PR China
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Klein MT, Teitler M. Guinea pig hippocampal 5-HT(1E) receptors: a tool for selective drug development. J Neurochem 2009; 109:268-74. [PMID: 19200348 DOI: 10.1111/j.1471-4159.2009.05958.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recent studies have indicated that the serotonin [5-hydroxytryptamine (5-HT)] 1E receptor, originally discovered in human brain tissue, is not expressed in rat or mouse brain. Thus, there have been few reports on 5-HT(1E) receptor drug development. However, expression of 5-HT(1E) receptor mRNA has been shown in guinea pig brain. To establish this species as an animal model for 5-HT(1E) drug development, we identified brain regions that exhibit 5-carboxyamidotryptamine, ritanserin, and LY344864 - insensitive [(3)H]5-HT binding (characteristic of the 5-HT(1E) receptor). In hippocampal homogenates, where 5-HT(1E) receptor density was sufficiently high for radioligand binding analysis, 100 nM 5-carboxyamidotryptamine, 30 nM ritanserin, and 100 nM LY344864 were used to mask [(3)H]5-HT binding at non-5-HT(1E) receptors. The K(d) of [(3)H]5-HT was 5.7 +/- 0.7 nM and is indistinguishable from the cloned receptor K(d) of 6.5 +/- 0.6 nM. The affinities of 16 drugs for the cloned and hippocampal-expressed guinea pig 5-HT(1E) receptors are essentially identical (R(2) = 0.97). These findings indicate that using these conditions autoradiographical distribution and signal transduction studies of the 5-HT(1E) receptor in guinea pig brain are feasible. Using the guinea pig as an animal model should provide important insights into possible functions of this receptor and the therapeutic potential of selective human 5-HT(1E) drugs.
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Affiliation(s)
- Michael T Klein
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York 12208, USA
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Knight JA, Smith C, Toohey N, Klein MT, Teitler M. Pharmacological analysis of the novel, rapid, and potent inactivation of the human 5-Hydroxytryptamine7 receptor by risperidone, 9-OH-Risperidone, and other inactivating antagonists. Mol Pharmacol 2008; 75:374-80. [PMID: 18996971 DOI: 10.1124/mol.108.052084] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In a previous publication, using human 5-hydroxytryptamine(7) (h5-HT(7)) receptor-expressing human embryonic kidney (HEK) 293 cells, we reported the rapid, potent inactivation of the h5-HT(7) receptor stimulation of cAMP production by three antagonists: risperidone, 9-OH-risperidone, and methiothepin (Smith et al., 2006). To better understand the drug-receptor interaction producing the inactivation, we 1) expanded the list of inactivating drugs, 2) determined the inactivating potencies and efficacies by performing concentration-response experiments, and 3) determined the potencies and efficacies of the inactivators as irreversible binding site inhibitors. Three new drugs were found to fully inactivate the h5-HT(7) receptor: lisuride, bromocryptine, and metergoline. As inactivators, these drugs displayed potencies of 1, 80, and 321 nM, respectively. Pretreatment of 5-HT(7)-expressing HEK cells with increasing concentrations of the inactivating drugs risperidone, 9-OH-risperidone, methiothepin, lisuride, bromocriptine, and metergoline potently inhibited radiolabeling of the h5-HT(7) receptor, with IC(50) values of 9, 5.5, 152, 3, 73, and 10 nM, respectively. We were surprised to find that maximal concentrations of risperidone and 9-OH-risperidone inhibited only 50% of the radiolabeling of h5-HT(7) receptors. These results indicate that risperidone and 9-OH risperidone may be producing 5-HT(7) receptor inactivation by different mechanisms than lisuride, bromocryptine, metergoline, and methiothepin. These results are not interpretable using the conventional model of G-protein-coupled receptor function. The complex seems capable of assuming a stable inactive conformation as a result of the interaction of certain antagonists. The rapid, potent inactivation of the receptor-G-protein complex by antagonists implies a constitutive, pre-existing complex between the h5-HT(7) receptor and a G-protein.
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Affiliation(s)
- Jessica A Knight
- Center for Neuropharmacology and Neuroscience, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208.
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Bruchas MR, Yang T, Schreiber S, DeFino M, Kwan SC, Li S, Chavkin C. Long-acting kappa opioid antagonists disrupt receptor signaling and produce noncompetitive effects by activating c-Jun N-terminal kinase. J Biol Chem 2007; 282:29803-11. [PMID: 17702750 PMCID: PMC2096775 DOI: 10.1074/jbc.m705540200] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Norbinaltorphimine (NorBNI), guanidinonaltrindole, and atrans-(3R,4R)-dimethyl-4-(3-hydroxyphenyl) piperidine (JDTic) are selective kappa opioid receptor (KOR) antagonists having very long durations of action in vivo despite binding non-covalently in vitro and having only moderately high affinities. Consistent with this, we found that antagonist treatment significantly reduced the subsequent analgesic response of mice to the KOR agonist U50,488 in the tail-withdrawal assay for 14-21 days. Receptor protection assays were designed to distinguish between possible explanations for this anomalous effect, and we found that mice pretreated with the readily reversible opioid antagonists naloxone or buprenorphine before norBNI responded strongly in the tail-flick analgesia assay to a subsequent challenge with U50,488 1 week later. Protection by a rapidly cleared reagent indicates that norBNI did not persist at the site of action. In vitro binding of [(3)H]U69,593 to KOR showed that K(d) and Bmax values were not significantly affected by prior in vivo norBNI exposure, indicating that the agonist binding site was intact. Consistent with the concept that the long-lasting effects might be caused by a functional disruption of KOR signaling, both norBNI and JDTic were found to stimulate c-Jun N-terminal kinase (JNK) phosphorylation in HEK293 cells expressing KOR-GFP but not in untransfected cells. Similarly, norBNI increased phospho-JNK in both the striatum and spinal cord in wild type mice but not in KOR knock-out mice. Pretreatment of mice with the JNK inhibitor SP600125 before norBNI attenuated the long acting antagonism. Together, these results suggest that the long duration KOR antagonists disrupt KOR signaling by activating JNK.
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Affiliation(s)
- Michael R. Bruchas
- From the Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | | | - Selena Schreiber
- From the Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | - Mia DeFino
- From the Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | - Steven C. Kwan
- From the Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | | | - Charles Chavkin
- From the Department of Pharmacology, University of Washington, Seattle, Washington 98195
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Rauly-Lestienne I, Boutet-Robinet E, Ailhaud MC, Newman-Tancredi A, Cussac D. Differential profile of typical, atypical and third generation antipsychotics at human 5-HT7a receptors coupled to adenylyl cyclase: detection of agonist and inverse agonist properties. Naunyn Schmiedebergs Arch Pharmacol 2007; 376:93-105. [PMID: 17786406 DOI: 10.1007/s00210-007-0182-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Accepted: 07/29/2007] [Indexed: 11/24/2022]
Abstract
5-HT(7) receptors are present in thalamus and limbic structures, and a possible role of these receptors in the pathology of schizophrenia has been evoked. In this study, we examined binding affinity and agonist/antagonist/inverse agonist properties at these receptors of a large series of antipsychotics, i.e., typical, atypical, and third generation compounds preferentially targeting D(2) and 5-HT(1A) sites. Adenylyl cyclase (AC) activity was measured in HEK293 cells stably expressing the human (h) 5-HT(7a) receptor isoform. 5-HT and 5-CT increased cyclic adenosine monophosphate level by about 20-fold whereas (+)-8-OH-DPAT, the antidyskinetic agent sarizotan, and the novel antipsychotic compound bifeprunox exhibited partial agonist properties at h5-HT(7a) receptors stimulating AC. Other compounds antagonized 5-HT-induced AC activity with pK (B) values which correlated with their pK (i) as determined by competition binding vs [(3)H]5-CT. The selective 5-HT(7) receptor ligand, SB269970, was the most potent antagonist. For antipsychotic compounds, the following rank order of antagonism potency (pK (B)) was ziprasidone > tiospirone > SSR181507 > or = clozapine > or = olanzapine > SLV-314 > SLV-313 > or = aripiprazole > or = chlorpromazine > nemonapride > haloperidol. Interestingly, pretreatment of HEK293-h5-HT(7a) cells with forskolin enhanced basal AC activity and revealed inverse agonist properties for both typical and atypical antipsychotics as well as for aripiprazole. In contrast, other novel antipsychotics exhibited diverse 5-HT(7a) properties; SLV-313 and SLV-314 behaved as quasi-neutral antagonists, SSR181507 acted as an inverse agonist, and bifeprunox as a partial agonist, as mentioned above. In conclusion, the differential properties of third generation antipsychotics at 5-HT(7) receptors may influence their antipsychotic profile.
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Affiliation(s)
- Isabelle Rauly-Lestienne
- Department of Cellular and Molecular Biology, Centre de Recherche Pierre Fabre, 17 avenue Jean Moulin, 81106 Castres Cedex, France
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