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Brunetti L, Francavilla F, Leopoldo M, Lacivita E. Allosteric Modulators of Serotonin Receptors: A Medicinal Chemistry Survey. Pharmaceuticals (Basel) 2024; 17:695. [PMID: 38931362 PMCID: PMC11206742 DOI: 10.3390/ph17060695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/15/2024] [Accepted: 05/23/2024] [Indexed: 06/28/2024] Open
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter regulating numerous physiological functions, and its dysregulation is a crucial component of the pathological processes of schizophrenia, depression, migraines, and obesity. 5-HT interacts with 14 different receptors, of which 5-HT1A-1FRs, 5-HT2A-CRs, and 5-HT4-7Rs are G protein-coupled receptors (GPCRs), while 5-HT3R is a ligand-gated ion channel. Over the years, selective orthosteric ligands have been identified for almost all serotonin receptors, yielding several clinically relevant drugs. However, the high degree of homology between 5-HTRs and other GPCRs means that orthosteric ligands can have severe side effects. Thus, there has recently been increased interest in developing safer ligands of GPCRs, which bind to less conserved, more specific sites, distinct from that of the receptor's natural ligand. The present review describes the identification of allosteric ligands of serotonin receptors, which are largely natural compounds (oleamide, cannabidiol, THC, and aporphine alkaloids), complemented by synthetic modulators developed in large part for the 5-HT2C receptor. The latter are positive allosteric modulators sought after for their potential as drugs preferable over the orthosteric agonists as antiobesity agents for their potentially safer profile. When available, details on the interactions between the ligand and allosteric binding site will be provided. An outlook on future research in the field will also be provided.
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Affiliation(s)
| | | | - Marcello Leopoldo
- Department of Pharmacy–Drug Sciences, University of Bari Aldo Moro, 70125 Bari, Italy; (L.B.); (F.F.); (E.L.)
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Muñoz-Montesino C, Burgos CF, Lara CO, Riquelme CR, Flaig D, San Martin VP, Aguayo LG, Fuentealba J, Castro PA, Guzmán L, Yévenes GE, Moraga-Cid G. Inhibition of the Glycine Receptor alpha 3 Function by Colchicine. Front Pharmacol 2020; 11:1143. [PMID: 32903667 PMCID: PMC7438739 DOI: 10.3389/fphar.2020.01143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 07/13/2020] [Indexed: 11/22/2022] Open
Abstract
Colchicine is a plant alkaloid that is widely used as a therapeutic agent. It is widely accepted that colchicine reduces the production of inflammatory mediators mainly by altering cytoskeleton dynamics due to its microtubule polymerization inhibitory activity. However, other lines of evidence have shown that colchicine exerts direct actions on the function of ion channels, which are independent of cytoskeleton alterations. Colchicine is able to modify the function of several pentameric ligand-gated ion channels, including glycine receptors (GlyRs). Previous electrophysiological studies have shown that colchicine act as an antagonist of GlyRs composed by the α1 subunit. In addition, it was recently demonstrated that colchicine directly bind to the α3 subunit of GlyRs. Interestingly, other studies have shown a main role of α3GlyRs on chronic inflammatory pain. Nevertheless, the functional effects of colchicine on the α3GlyR function are still unknown. Here, by using electrophysiological techniques and bioinformatics, we show that colchicine inhibited the function of the α3GlyRs. Colchicine elicited concentration-dependent inhibitory effects on α3GlyRs at micromolar range and decreased the apparent affinity for glycine. Single-channel recordings show that the colchicine inhibition is associated with a decrease in the open probability of the ion channel. Molecular docking assays suggest that colchicine preferentially bind to the orthosteric site in the closed state of the ion channel. Altogether, our results suggest that colchicine is a competitive antagonist of the α3GlyRs.
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Rizk OH, Shaaban OG, Abdel Wahab AE. Synthesis of Oxadiazolyl, Pyrazolyl and Thiazolyl Derivatives of Thiophene-2-Carboxamide as Antimicrobial and Anti-HCV Agents. THE OPEN MEDICINAL CHEMISTRY JOURNAL 2017; 11:38-53. [PMID: 28553409 PMCID: PMC5427694 DOI: 10.2174/1874104501711010038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/06/2017] [Accepted: 01/11/2017] [Indexed: 12/12/2022]
Abstract
Introduction: Three series of pyrazole, thiazole and 1,3,4-oxadiazole, derivatives were synthesized starting from 5-amino-4-(hydrazinocarbonyl)-3-methylthiophene-2-carboxamide (2). Methods: All compounds were investigated for their preliminary antimicrobial activity. They were proved to exhibit remarkable antimicrobial activity against Pseudomonas aeruginosa with insignificant activity towards Gram positive bacterial strains and fungi. Results: In-vitro testing of the new compounds on hepatitis-C virus (HCV) replication in hepatocellular carcinoma cell line HepG2 infected with the virus utilizing the reverse transcription polymerase chain reaction technique (RT-PCR) generally showed inhibition of the replication of HCV RNA (–) strands at low concentration, while, eight compounds; 3a, 6, 7a, 7b, 9a, 9b, 10a and 11b proved to inhibit the replication of HCV RNA (+) and (–) strands at very low concentration range 0.08-0.36 μg/mL. Conclusion: Compounds 7b and 11b displayed the highest anti-HCV and antimicrobial activities in this study.
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Affiliation(s)
- Ola H Rizk
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Alexandria, Alexandria, Egypt.,Department of Analytical and Pharmaceutical Chemistry, Faculty of Pharmacy & Drug Manufacturing, Pharos University, Alexandria, Egypt
| | - Omaima G Shaaban
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Alexandria, Alexandria, Egypt.,Department of Analytical and Pharmaceutical Chemistry, Faculty of Pharmacy & Drug Manufacturing, Pharos University, Alexandria, Egypt
| | - Abeer E Abdel Wahab
- Genetic Engineering and Biotechnology Research Institute (GEBRI), Mubarak City for Scientific Research and Technology Application, Borg El-Arab, Alexandria, Egypt
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Pandhare A, Pappu AS, Wilms H, Blanton MP, Jansen M. The antidepressant bupropion is a negative allosteric modulator of serotonin type 3A receptors. Neuropharmacology 2016; 113:89-99. [PMID: 27671323 DOI: 10.1016/j.neuropharm.2016.09.021] [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: 07/12/2016] [Revised: 09/12/2016] [Accepted: 09/21/2016] [Indexed: 11/27/2022]
Abstract
The FDA-approved antidepressant and smoking cessation drug bupropion is known to inhibit dopamine and norepinephrine reuptake transporters, as well as nicotinic acetylcholine receptors (nAChRs) which are cation-conducting members of the Cys-loop superfamily of ion channels, and more broadly pentameric ligand-gated ion channels (pLGICs). In the present study, we examined the ability of bupropion and its primary metabolite hydroxybupropion to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs), and further characterized bupropion's pharmacological effects at these receptors. Mouse 5-HT3ARs were heterologously expressed in HEK-293 cells or Xenopus laevis oocytes for equilibrium binding studies. In addition, the latter expression system was utilized for functional studies by employing two-electrode voltage-clamp recordings. Both bupropion and hydroxybupropion inhibited serotonin-gated currents from 5-HT3ARs reversibly and dose-dependently with inhibitory potencies of 87 μM and 112 μM, respectively. Notably, the measured IC50 value for hydroxybupropion is within its therapeutically-relevant concentrations. The blockade by bupropion was largely non-competitive and non-use-dependent. Unlike its modulation at cation-selective pLGICs, bupropion displayed no significant inhibition of the function of anion-selective pLGICs. In summary, our results demonstrate allosteric blockade by bupropion of the 5-HT3AR. Importantly, given the possibility that bupropion's major active metabolite may achieve clinically relevant concentrations in the brain, our novel findings delineate a not yet identified pharmacological principle underlying its antidepressant effect.
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Affiliation(s)
- Akash Pandhare
- Department of Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
| | - Aneesh Satya Pappu
- Department of Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; The Clark Scholar Program, Texas Tech University, Lubbock, TX 79409, USA.
| | - Henrik Wilms
- Department of Neurology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
| | - Michael Paul Blanton
- Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
| | - Michaela Jansen
- Department of Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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Gorbunov EA, Ertuzun IA, Kachaeva EV, Tarasov SA, Epstein OI. In vitro screening of major neurotransmitter systems possibly involved in the mechanism of action of antibodies to S100 protein in released-active form. Neuropsychiatr Dis Treat 2015; 11:2837-46. [PMID: 26604768 PMCID: PMC4639559 DOI: 10.2147/ndt.s92456] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Experimentally and clinically, it was shown that released-active form of antibodies to S100 protein (RAF of Abs to S100) exerts a wide range of pharmacological activities: anxiolytic, antiasthenic, antiaggressive, stress-protective, antihypoxic, antiischemic, neuroprotective, and nootropic. The purpose of this study was to determine the influence of RAF of Abs to S100 on major neurotransmitter systems (serotoninergic, GABAergic, dopaminergic, and on sigma receptors as well) which are possibly involved in its mechanism of pharmacological activity. Radioligand binding assays were used for assessment of the drug influence on ligand-receptor interaction. [(35)S]GTPγS binding assay, cyclic adenosine monophosphate HTRF™, cellular dielectric spectroscopy assays, and assays based on measurement of intracellular concentration of Ca(2+) ions were used for assessment of agonist or antagonist properties of the drug toward receptors. RAF of Abs to S100 increased radioligand binding to 5-HT1F, 5-HT2B, 5-HT2Cedited, 5-HT3, and to D3 receptors by 142.0%, 131.9%, 149.3%, 120.7%, and 126.3%, respectively. Also, the drug significantly inhibited specific binding of radioligands to GABAB1A/B2 receptors by 25.8%, and to both native and recombinant human sigma1 receptors by 75.3% and 40.32%, respectively. In the functional assays, it was shown that the drug exerted antagonism at 5-HT1B, D3, and GABAB1A/B2 receptors inhibiting agonist-induced responses by 23.24%, 32.76%, and 30.2%, respectively. On the contrary, the drug exerted an agonist effect at 5-HT1A receptors enhancing receptor functional activity by 28.0%. The pharmacological profiling of RAF of Abs to S100 among 27 receptor provides evidence for drug-related modification of major neurotransmitter systems.
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Affiliation(s)
| | - Irina A Ertuzun
- OOO "NPF "MATERIA MEDICA HOLDING", Moscow, Russian Federation
| | | | | | - Oleg I Epstein
- OOO "NPF "MATERIA MEDICA HOLDING", Moscow, Russian Federation
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Lansdell SJ, Sathyaprakash C, Doward A, Millar NS. Activation of human 5-hydroxytryptamine type 3 receptors via an allosteric transmembrane site. Mol Pharmacol 2014; 87:87-95. [PMID: 25338672 DOI: 10.1124/mol.114.094540] [Citation(s) in RCA: 23] [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 common with other members of the Cys-loop family of pentameric ligand-gated ion channels, 5-hydroxytryptamine type 3 receptors (5-HT3Rs) are activated by the binding of a neurotransmitter to an extracellular orthosteric site, located at the interface of two adjacent receptor subunits. In addition, a variety of compounds have been identified that modulate agonist-evoked responses of 5-HT3Rs, and other Cys-loop receptors, by binding to distinct allosteric sites. In this study, we examined the pharmacological effects of a group of monoterpene compounds on recombinant 5-HT3Rs expressed in Xenopus oocytes. Two phenolic monoterpenes (carvacrol and thymol) display allosteric agonist activity on human homomeric 5-HT3ARs (64 ± 7% and 80 ± 4% of the maximum response evoked by the endogenous orthosteric agonist 5-HT, respectively). In addition, at lower concentrations, where agonist effects are less apparent, carvacrol and thymol act as potentiators of responses evoked by submaximal concentrations of 5-HT. By contrast, carvacrol and thymol have no agonist or potentiating activity on the closely related mouse 5-HT3ARs. Using subunit chimeras containing regions of the human and mouse 5-HT3A subunits, and by use of site-directed mutagenesis, we have identified transmembrane amino acids that either abolish the agonist activity of carvacrol and thymol on human 5-HT3ARs or are able to confer this property on mouse 5-HT3ARs. By contrast, these mutations have no significant effect on orthosteric activation of 5-HT3ARs by 5-HT. We conclude that 5-HT3ARs can be activated by the binding of ligands to an allosteric transmembrane site, a conclusion that is supported by computer docking studies.
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Affiliation(s)
- Stuart J Lansdell
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, United Kingdom
| | - Chaitra Sathyaprakash
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, United Kingdom
| | - Anne Doward
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, United Kingdom
| | - Neil S Millar
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, United Kingdom
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Thompson AJ. Recent developments in 5-HT3 receptor pharmacology. Trends Pharmacol Sci 2013; 34:100-9. [DOI: 10.1016/j.tips.2012.12.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/07/2012] [Accepted: 12/10/2012] [Indexed: 12/19/2022]
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Marques-da-Silva C, Chaves MM, Castro NG, Coutinho-Silva R, Guimaraes MZP. Colchicine inhibits cationic dye uptake induced by ATP in P2X2 and P2X7 receptor-expressing cells: implications for its therapeutic action. Br J Pharmacol 2011; 163:912-26. [PMID: 21306580 DOI: 10.1111/j.1476-5381.2011.01254.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE The two longest C-termini of the purinergic P2X receptors occur in the P2X2 and P2X7 receptors and are thought to interact with multiple cytoplasmic proteins, among which are members of the cytoskeleton, including microtubules. In this work we asked whether disrupting the microtubule cytoskeleton might affect the functions of these receptors. EXPERIMENTAL APPROACH Functions of heterologously expressed P2X2 and P2X7 receptors were evaluated with electrophysiology and dye uptake following ATP application. Permeabilization and secretion of pro-inflammatory agents were quantified from fresh or cultured peritoneal mouse macrophages, treated in vitro or in vivo with colchicine. KEY RESULTS Disrupting the microtubule network with colchicine did not affect currents generated by ATP in P2X2 and P2X7 receptor-expressing cells but inhibited uptake of the dye Yo-Pro-1 in Xenopus oocytes and HEK293 cells expressing these channels. Peritoneal mouse macrophages showed less ATP-induced permeabilization to ethidium bromide in the presence of colchicine, and less reactive oxygen species (ROS) formation, nitric oxide (NO) and interleukin (IL)-1β release. Colchicine treatment did not affect ATP-evoked currents in macrophages. Finally, in vivo assays with mice inoculated with lipopolysaccharide and ATP showed diminished ROS, IL-1β, interferon-γ and NO production after colchicine treatment. CONCLUSIONS AND IMPLICATIONS Colchicine has known anti-inflammatory actions and is used to treat several conditions involving innate immunity, including gout and familial Mediterranean fever. Here we propose a new mechanism of action - inhibition of pore formation induced by activation of P2X receptors - which could explain some of the anti-inflammatory effects of colchicine.
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Affiliation(s)
- C Marques-da-Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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