1
|
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.
Collapse
Affiliation(s)
| | | | - Marcello Leopoldo
- Department of Pharmacy–Drug Sciences, University of Bari Aldo Moro, 70125 Bari, Italy; (L.B.); (F.F.); (E.L.)
| | | |
Collapse
|
2
|
Lopes LT, Canto-de-Souza L, Baptista-de-Souza D, de Souza RR, Nunes-de-Souza RL, Canto-de-Souza A. The interplay between 5-HT 2C and 5-HT 3A receptors in the dorsal periaqueductal gray mediates anxiety-like behavior in mice. Behav Brain Res 2022; 417:113588. [PMID: 34547341 DOI: 10.1016/j.bbr.2021.113588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/17/2021] [Accepted: 09/15/2021] [Indexed: 11/17/2022]
Abstract
The monoamine neurotransmitter serotonin (5-HT) modulates anxiety by its activity on 5-HT2C receptors (5-HT2CR) expressed in the dorsal periaqueductal gray (dPAG). Here, we investigated the presence of 5-HT3A receptors (5-HT3AR) in the dPAG, and the interplay between 5-HT2CR and 5-HT3AR in the dPAG in mediating anxiety-like behavior in mice. We found that 5-HT3AR is expressed in the dPAG and the blockade of these receptors using intra-dPAG infusion of ondansetron (5-HT3AR antagonist; 3.0 nmol) induced an anxiogenic-like effect. The activation of 5-HT3ABR by the infusion of mCPBG [1-(m-Chlorophenyl)-biguanide; 5-HT3R agonist] did not alter anxiety-like behaviors. In addition, blockade of 5-HT3AR (1.0 nmol) prevented the anxiolytic-like effect induced by the infusion of the 5-HT2CR agonist mCPP (1-(3-chlorophenyl) piperazine; 0.03 nmol). None of the treatment effects on anxiety-like behaviors altered the locomotor activity levels. The present results suggest that the anxiolytic-like effect exerted by serotonin activity on 5-HT2CR in the dPAG is modulated by 5-HT3AR expressed in same region.
Collapse
Affiliation(s)
- Luana Tenorio Lopes
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, Alberta, Canada.
| | - Lucas Canto-de-Souza
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, Univ. Estadual Paulista, UNESP, Araraquara, SP 14801-902, Brazil; Neuroscience and Behavioral Institute, Av. do Café, 2.450, 14050-220 Ribeirão Preto, SP, Brazil.
| | - Daniela Baptista-de-Souza
- Psychobiology Group/Department of Psychology/CECH-UFSCar, São Carlos, SP 13565-905, Brazil; Laboratory of Pharmacology, School of Pharmaceutical Sciences, Univ. Estadual Paulista, UNESP, Araraquara, SP 14801-902, Brazil; Neuroscience and Behavioral Institute, Av. do Café, 2.450, 14050-220 Ribeirão Preto, SP, Brazil.
| | - Rimenez Rodrigues de Souza
- The University of Texas at Dallas, School of Behavior and Brain Sciences, 800 West Campbell Road, Richardson, TX 75080-3021, United States; The University of Texas at Dallas, Texas Biomedical Device Center, 800 West Campbell Road, Richardson, TX 75080-3021, United States.
| | - Ricardo L Nunes-de-Souza
- Psychobiology Group/Department of Psychology/CECH-UFSCar, São Carlos, SP 13565-905, Brazil; Joint Graduate Program in Physiological Sciences UFSCar/UNESP, Rod. Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil; Laboratory of Pharmacology, School of Pharmaceutical Sciences, Univ. Estadual Paulista, UNESP, Araraquara, SP 14801-902, Brazil; Neuroscience and Behavioral Institute, Av. do Café, 2.450, 14050-220 Ribeirão Preto, SP, Brazil.
| | - Azair Canto-de-Souza
- Psychobiology Group/Department of Psychology/CECH-UFSCar, São Carlos, SP 13565-905, Brazil; Joint Graduate Program in Physiological Sciences UFSCar/UNESP, Rod. Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil; Graduate Program in Psychology UFSCar, Rod. Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil; Neuroscience and Behavioral Institute, Av. do Café, 2.450, 14050-220 Ribeirão Preto, SP, Brazil.
| |
Collapse
|
3
|
Irving H, Turek I, Kettle C, Yaakob N. Tapping into 5-HT 3 Receptors to Modify Metabolic and Immune Responses. Int J Mol Sci 2021; 22:ijms222111910. [PMID: 34769340 PMCID: PMC8584345 DOI: 10.3390/ijms222111910] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 02/07/2023] Open
Abstract
5-hydroxytryptamine type 3 (5-HT3) receptors are ligand gated ion channels, which clearly distinguish their mode of action from the other G-protein coupled 5-HT or serotonin receptors. 5-HT3 receptors are well established targets for emesis and gastrointestinal mobility and are used as adjunct targets in treating schizophrenia. However, the distribution of these receptors is wider than the nervous system and there is potential that these additional sites can be targeted to modulate inflammatory and/or metabolic conditions. Recent progress in structural biology and pharmacology of 5-HT3 receptors have provided profound insights into mechanisms of their action. These advances, combined with insights into clinical relevance of mutations in genes encoding 5-HT3 subunits and increasing understanding of their implications in patient's predisposition to diseases and response to the treatment, open new avenues for personalized precision medicine. In this review, we recap on the current status of 5-HT3 receptor-based therapies using a biochemical and physiological perspective. We assess the potential for targeting 5-HT3 receptors in conditions involving metabolic or inflammatory disorders based on recent findings, underscoring the challenges and limitations of this approach.
Collapse
Affiliation(s)
- Helen Irving
- Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo, VIC 3550, Australia; (I.T.); (C.K.)
- Correspondence:
| | - Ilona Turek
- Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo, VIC 3550, Australia; (I.T.); (C.K.)
| | - Christine Kettle
- Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo, VIC 3550, Australia; (I.T.); (C.K.)
| | - Nor Yaakob
- Drug and Herbal Research Centre, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia;
| |
Collapse
|
4
|
Duarte D, Cardoso A, Vale N. Synergistic Growth Inhibition of HT-29 Colon and MCF-7 Breast Cancer Cells with Simultaneous and Sequential Combinations of Antineoplastics and CNS Drugs. Int J Mol Sci 2021; 22:ijms22147408. [PMID: 34299028 PMCID: PMC8306770 DOI: 10.3390/ijms22147408] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/06/2021] [Accepted: 07/08/2021] [Indexed: 02/06/2023] Open
Abstract
Several central nervous system (CNS) drugs exhibit potent anti-cancer activities. This study aimed to design a novel model of combination that combines different CNS agents and antineoplastic drugs (5-fluorouracil (5-FU) and paclitaxel (PTX)) for colorectal and breast cancer therapy, respectively. Cytotoxic effects of 5-FU and PTX alone and in combination with different CNS agents were evaluated on HT-29 colon and MCF-7 breast cancer cells, respectively. Three antimalarials alone and in combination with 5-FU were also evaluated in HT-29 cells. Different schedules and concentrations in a fixed ratio were added to the cultured cells and incubated for 48 h. Cell viability was evaluated using MTT and SRB assays. Synergism was evaluated using the Chou-Talalay, Bliss Independence and HSA methods. Our results demonstrate that fluphenazine, fluoxetine and benztropine have enhanced anticancer activity when used alone as compared to being used in combination, making them ideal candidates for drug repurposing in colorectal cancer (CRC). Regarding MCF-7 cells, sertraline was the most promising candidate alone for drug repurposing, with the lowest IC50 value. For HT-29 cells, the CNS drugs sertraline and thioridazine in simultaneous combination with 5-FU demonstrated the strongest synergism among all combinations. In MCF-7 breast cancer cells, the combination of fluoxetine, fluphenazine and benztropine with PTX resulted in synergism for all concentrations below IC50. We also found that the antimalarial artesunate administration prior to 5-FU produces better results in reducing HT-29 cell viability than the inverse drug schedule or the simultaneous combination. These results demonstrate that CNS drugs activity differs between the two selected cell lines, both alone and in combination, and support that some CNS agents may be promising candidates for drug repurposing in these types of cancers. Additionally, these results demonstrate that 5-FU or a combination of PTX with CNS drugs should be further evaluated. These results also demonstrate that antimalarial drugs may also be used as antitumor agents in colorectal cancer, besides breast cancer.
Collapse
Affiliation(s)
- Diana Duarte
- OncoPharma Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal;
- Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Armando Cardoso
- NeuroGen Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal;
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Nuno Vale
- OncoPharma Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal;
- Department of Community Medicine, Health Information and Decision (MEDCIDS), Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
- Correspondence:
| |
Collapse
|
5
|
Zhang Y, Wang K, Yu Z. Drug Development in Channelopathies: Allosteric Modulation of Ligand-Gated and Voltage-Gated Ion Channels. J Med Chem 2020; 63:15258-15278. [PMID: 33253554 DOI: 10.1021/acs.jmedchem.0c01304] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ion channels have been characterized as promising drug targets for treatment of numerous human diseases. Functions of ion channels can be fine-tuned by allosteric modulators, which interact with channels and modulate their activities by binding to sites spatially discrete from those of orthosteric ligands. Positive and negative allosteric modulators have presented a plethora of potential therapeutic advantages over traditionally orthosteric agonists and antagonists in terms of selectivity and safety. This thematic review highlights the discovery of representative allosteric modulators for ligand-gated and voltage-gated ion channels, discussing in particular their identifications, locations, and therapeutic uses in the treatment of a range of channelopathies. Additionally, structures and functions of selected ion channels are briefly described to aid in the rational design of channel modulators. Overall, allosteric modulation represents an innovative targeting approach, and the corresponding modulators provide an abundant but challenging landscape for novel therapeutics targeting ligand-gated and voltage-gated ion channels.
Collapse
Affiliation(s)
- Yanyun Zhang
- Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Ke Wang
- Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Zhiyi Yu
- Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| |
Collapse
|
6
|
Fierro L. Serotonin-gated inward currents are three times more frequent in rat hairy skin sensory afferents than in those innervating the skeletal muscle. Mol Pain 2018; 13:1744806917729055. [PMID: 28868961 PMCID: PMC5588798 DOI: 10.1177/1744806917729055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Tight whole-cell patch clamp was performed in 191 DiI (1,1'-dioctadecyl-3,3,3'3'-tetramethylindocarbocyanine perchlorate) retrogradely labeled rat sensory afferents from skin shoulders ( n = 93) and biceps femoris muscles ( n = 98). 5-HT-gated inward currents were evoked with 50-µM serotonin (5-HT; 5-hydroxytryptamine), and their frequency and current densities were compared between skin and skeletal muscle sensory afferents. To evaluate if 5-HT-gated inward currents coexist with other ligand-gated currents, the skin and skeletal muscle sensory afferents were also sequentially exposed to external solution at pH 6.8, ATP (50 µM), and capsaicin (1 µM). 5-HT evoked inward currents in 72% (67 of 93) of hairy skin sensory afferents and in only 24% (24 of 98) of skeletal muscle sensory afferents, and this difference was statistically significant ( p < 0.0000, chi-square test). The current densities obtained in hairy skin and skeletal muscle sensory afferents were not significantly different. They were -45.8 ± 7.7 and -32.4 ± 10.5 pA/pF, respectively (mean ± SEM, p < 0.30734). These results indicate that 5-HT-gated inward currents are three times more frequently evoked in small- to medium-sized sensory afferents (25-40 µm) innervating the hairy skin than on those innervating the skeletal muscle. When cells were gathered in two clusters, the difference was four times larger in the small-sized cluster (25-32 µm) and two times larger in the medium-sized cluster (33-40 µm). The results can be explained if the superficial somatic (cutaneous) nociceptive system is more exposed than the deep somatic nociceptive system (musculoskeletal) to physical and chemical stimuli inducing 5-HT-mediated inflammatory pain.
Collapse
Affiliation(s)
- Leonardo Fierro
- Leonardo Fierro, Universidad del Valle, Calle 4 B No. 36–00, Edificio 116, Oficina 5001, Cali, Valle del Cauca 760042, Colombia.
| |
Collapse
|
7
|
Dothel G, Barbaro MR, Raschi E, Barbara G, De Ponti F. Advancements in drug development for diarrhea-predominant irritable bowel syndrome. Expert Opin Investig Drugs 2018; 27:251-263. [PMID: 29451407 DOI: 10.1080/13543784.2018.1442434] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common disorder characterized by a complex pathophysiology hampering optimal targeted drug development. Recent advances in our understanding of key underlying mechanisms prompted novel therapeutics including novel pharmacological approaches. AREAS COVERED This review summarizes the latest advancements in the pipeline of IBS-D drugs focusing on new pharmacological targets, efficacy and safety of medicinal products considering the recent harmonization of regulatory requirements by the FDA and the EMA. EXPERT OPINION The new 5-HT3 receptor antagonist ramosetron appears a promising therapeutic approach devoid of significant adverse events, although it is presently unavailable in Western countries, most likely because of the precautionary approach taken by regulatory agencies with this drug class. New pharmacological concepts on full agonists/antagonists, mixed-receptor activity and novel drug targets may streamline the present drug pipeline along with the adherence on new regulatory guidelines on outcome measures. Eluxadoline can be taken as an example of this paradigm shift. It has now been granted marketing authorization for IBS-D on both sides of the Atlantic, but it is still considered as a second-line agent by the NICE. There is still much work to be done to fully cover clinical needs of patients with IBS-D.
Collapse
Affiliation(s)
- Giovanni Dothel
- a Department of Medical and Surgical Sciences , University of Bologna , Bologna , Italy
| | | | - Emanuel Raschi
- a Department of Medical and Surgical Sciences , University of Bologna , Bologna , Italy
| | - Giovanni Barbara
- a Department of Medical and Surgical Sciences , University of Bologna , Bologna , Italy
| | - Fabrizio De Ponti
- a Department of Medical and Surgical Sciences , University of Bologna , Bologna , Italy
| |
Collapse
|
8
|
Peripheral 5-HT3 Receptors Are Involved in the Antinociceptive Effect of Bunodosine 391. Toxins (Basel) 2017; 10:toxins10010012. [PMID: 29280949 PMCID: PMC5793099 DOI: 10.3390/toxins10010012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/06/2017] [Accepted: 12/20/2017] [Indexed: 12/27/2022] Open
Abstract
Bunodosine 391 (BDS 391), a low molecular weight compound isolated from the sea anemone Bunodosoma cangicum, increases the nociceptive threshold and inhibits inflammatory hyperalgesia. Serotonin receptors are involved in those effects. In this study, we have expanded the characterization of the antinociceptive effect of BDS 391 demonstrating that, in rats: (a) the compound inhibits (1.2–12 ng/paw) overt pain, in the formalin test, and mechanical hyperalgesia (0.6–6.0 ng/paw) detected in a model of neuropathic pain; (b) intraplantar administration of ondansetron, a selective 5-HT3 receptor antagonist, blocks the effect of BDS 391, whereas ketanserin, a 5-HT2 receptor antagonist, partially reversed this effect, indicating the involvement of peripheral 5-HT2 and 5-HT3 receptors in BDS 391 antinociception; and (c) in binding assay studies, BDS 391 was not able to displace the selective 5-HT receptor antagonists, suggesting that this compound does not directly bind to these receptors. The effect of biguanide, a selective 5-HT3 receptor agonist, was also evaluated. The agonist inhibited the formalin’s nociceptive response, supporting an antinociceptive role for 5-HT3 receptors. Our study is the first one to show that a non-peptidic low molecular weight compound obtained from a sea anemone is able to induce antinociception and that activation of peripheral 5-HT3 receptors contributes to this effect.
Collapse
|
9
|
Sparling BA, DiMauro EF. Progress in the discovery of small molecule modulators of the Cys-loop superfamily receptors. Bioorg Med Chem Lett 2017; 27:3207-3218. [DOI: 10.1016/j.bmcl.2017.04.073] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 04/20/2017] [Accepted: 04/24/2017] [Indexed: 12/11/2022]
|
10
|
Price KL, Hirayama Y, Lummis SCR. Subtle Differences among 5-HT 3AC, 5-HT 3AD, and 5-HT 3AE Receptors Are Revealed by Partial Agonists. ACS Chem Neurosci 2017; 8:1085-1091. [PMID: 28367632 DOI: 10.1021/acschemneuro.6b00416] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
5-HT3 receptors are members of the Cys-loop family of ligand-gated ion channels, and, like most members of this family, there are multiple subunits that can contribute to functional pentameric receptors. 5-HT3A and 5-HT3AB receptors have been extensively characterized, but there are few studies on 5-HT3AC, 5-HT3AD, and 5-HT3AE receptors. Here we explore the properties of a range of partial agonists at 5-HT3AC, 5-HT3AD, and 5-HT3AE receptors following expression in Xenopus oocytes. The data show that the characteristics of receptor activation differ in the different heteromeric receptors when they are challenged with 5-HT, m-chlorophenylbiguanide (mCPBG), varenicline, 5-fluorotryptamine (5-FT), or thymol. 5-HT, 5-FT, varenicline, and mCPBG activation of 5-HT3AC, 5-HT3AD, and 5-HT3AE receptors yields similar EC50s to homomeric 5-HT3A receptors, but maximal responses differ. There are also differences in the levels of potentiation by thymol, which is greater at 5-HT3A receptors than 5-HT3AB, 5-HT3AC, 5-HT3AD, or 5-HT3AE receptors. Docking thymol into the receptor indicates a different residue in the transmembrane domain could provide an explanation for these data. Overall our study suggests that 5-HT3AC, 5-HT3AD, and 5-HT3AE have distinct pharmacological profiles to those of 5-HT3A and 5-HT3AB receptors; this is likely related to their distinct roles in the nervous system, consistent with their differential association with various disorders. Thus, these data pave the way for drugs that can specifically target these proteins.
Collapse
Affiliation(s)
- Kerry L. Price
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB 1QW, United Kingdom
| | - Yuri Hirayama
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB 1QW, United Kingdom
| | - Sarah C. R. Lummis
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB 1QW, United Kingdom
| |
Collapse
|
11
|
Celli J, Rappold G, Niesler B. The Human Serotonin Type 3 Receptor Gene (HTR3A-E) Allelic Variant Database. Hum Mutat 2016; 38:137-147. [PMID: 27763704 DOI: 10.1002/humu.23136] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/11/2016] [Accepted: 10/15/2016] [Indexed: 12/17/2022]
Abstract
Serotonin type 3 (5-HT3 ) receptors are ligand-gated ion channels formed by five subunits (5-HT3A-E), which are encoded by the HTR3A, HTR3B, HTR3C, HTR3D, and HTR3E genes. Functional receptors are pentameric complexes of diverse composition. Different receptor subtypes confer a predisposition to nausea and vomiting during chemotherapy, pregnancy, and following surgery. In addition, different subtypes contribute to neurogastroenterologic disorders such irritable bowel syndrome (IBS) and eating disorders as well as comorbid psychiatric conditions. 5-HT3 receptor antagonists are established treatments for emesis and IBS and are beneficial in the treatment of psychiatric diseases. Several case-control and pharmacogenetic studies have demonstrated an association between HTR3 variants and psychiatric and neurogastroenterologic phenotypes. Recently, their potential as predictors of nausea and vomiting and treatment of psychiatric disorders became evident. This information is now available in the serotonin receptor 3 HTR3 gene allelic variant database (www.htr3.uni-hd.de), which contains five sub-databases, one for each of the five different serotonin receptor genes HTR3A-E. Information on HTR3 variants, their functional relevance, associated phenotypes, and pharmacogenetic data such as drug response and side effects are available. This central information pool should help clinicians as well as scientists to evaluate their findings and to use the relevant information for subsequent genotype-phenotype correlation studies and pharmacogenetic approaches.
Collapse
Affiliation(s)
- Jacopo Celli
- Center of Human and Clinical Genetics, Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Gudrun Rappold
- Department of Human Molecular Genetics, University of Heidelberg, Heidelberg, Germany
| | - Beate Niesler
- Department of Human Molecular Genetics, University of Heidelberg, Heidelberg, Germany
| |
Collapse
|
12
|
Powell AD, Grafton G, Roberts A, Larkin S, O'Neill N, Palandri J, Otvos R, Cooper AJ, Ulens C, Barnes NM. Novel mechanism of modulation at a ligand-gated ion channel; action of 5-Cl-indole at the 5-HT 3 A receptor. Br J Pharmacol 2016; 173:3467-3479. [PMID: 27677804 DOI: 10.1111/bph.13638] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 09/09/2016] [Accepted: 09/16/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND AND PURPOSE The 5-HT3 receptor is a prototypical member of the Cys-loop ligand-gated ion channel (LGIC) superfamily and an established therapeutic target. In addition to activation via the orthosteric site, receptor function can be modulated by allosteric ligands. We have investigated the pharmacological action of Cl-indole upon the 5-HT3 A receptor and identified that this positive allosteric modulator possesses a novel mechanism of action for LGICs. EXPERIMENTAL APPROACH The impact of Cl-indole upon the 5-HT3 receptor was assessed using single cell electrophysiological recordings and [3 H]-granisetron binding in HEK293 cells stably expressing the 5-HT3 receptor. KEY RESULTS Cl-indole failed to evoke 5-HT3 A receptor-mediated responses (up to 30 μM) or display affinity for the [3 H]-granisetron binding site. However, in the presence of Cl-indole, termination of 5-HT application revealed tail currents mediated via the 5-HT3 A receptor that were independent of the preceding 5-HT concentration but were antagonized by the 5-HT3 receptor antagonist, ondansetron. These tail currents were absent in the 5-HT3 AB receptor. Furthermore, the presence of 5-HT revealed a concentration-dependent increase in the affinity of Cl-indole for the orthosteric binding site of the human 5-HT3 A receptor. CONCLUSIONS AND IMPLICATIONS Cl-indole acts as both an orthosteric agonist and an allosteric modulator, but the presence of an orthosteric agonist (e.g. 5-HT) is a prerequisite to reveal both actions. Precedent for ago-allosteric action is available, yet the essential additional presence of an orthosteric agonist is now reported for the first time. This widening of the pharmacological mechanisms to modulate LGICs may offer further therapeutic opportunities.
Collapse
Affiliation(s)
- Andrew D Powell
- Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.,School of Nursing Midwifery and Social Work, Birmingham City University, Edgbaston, UK
| | - Gillian Grafton
- Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Alexander Roberts
- Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Shannon Larkin
- Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Nathanael O'Neill
- Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Josephine Palandri
- Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Reka Otvos
- Department of Molecular and Cellular Neurobiology, VU University Amsterdam, Amsterdam, The Netherlands
| | - Alison J Cooper
- Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Chris Ulens
- Laboratory of Structural Neurobiology, KU Leuven, Leuven, Belgium
| | - Nicholas M Barnes
- Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.,Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|