1
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Zhu K, Liu C, Gao Y, Lu J, Wang D, Zhang H. Cryo-EM Structure and Activator Screening of Human Tryptophan Hydroxylase 2. Front Pharmacol 2022; 13:907437. [PMID: 36046836 PMCID: PMC9420949 DOI: 10.3389/fphar.2022.907437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/23/2022] [Indexed: 02/06/2023] Open
Abstract
Human tryptophan hydroxylase 2 (TPH2) is the rate-limiting enzyme in the synthesis of serotonin. Its dysfunction has been implicated in various psychiatric disorders such as depression, autism, and bipolar disorder. TPH2 is typically decreased in stability and catalytic activity in patients; thus, screening of molecules capable of binding and stabilizing the structure of TPH2 in activated conformation is desired for drug development in mental disorder treatment. Here, we solved the 3.0 Å cryo-EM structure of the TPH2 tetramer. Then, based on the structure, we conducted allosteric site prediction and small-molecule activator screening to the obtained cavity. ZINC000068568685 was successfully selected as the best candidate with highest binding affinity. To better understand the driving forces and binding stability of the complex, we performed molecular dynamics simulation, which indicates that ZINC000068568685 has great potential to stabilize the folding of the TPH2 tetramer to facilitate its activity. The research might shed light on the development of novel drugs targeting TPH2 for the treatment of psychological disorders.
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Affiliation(s)
- Kongfu Zhu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Chao Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Yuanzhu Gao
- Cryo-EM Facility Center, Southern University of Science and Technology, Shenzhen, China
| | - Jianping Lu
- Department of Child and Adolescent Psychiatry, Shenzhen Kangning Hospital, Shenzhen Mental Health Center, Shenzhen, China
| | - Daping Wang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
- Department of Orthopedics, Shenzhen Intelligent Orthopaedics and Biomedical Innovation Platform, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People’s Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, China
- *Correspondence: Daping Wang, ; Huawei Zhang,
| | - Huawei Zhang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, China
- *Correspondence: Daping Wang, ; Huawei Zhang,
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2
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Maffei ME. 5-Hydroxytryptophan (5-HTP): Natural Occurrence, Analysis, Biosynthesis, Biotechnology, Physiology and Toxicology. Int J Mol Sci 2020; 22:E181. [PMID: 33375373 PMCID: PMC7796270 DOI: 10.3390/ijms22010181] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 01/20/2023] Open
Abstract
L-5-hydroxytryptophan (5-HTP) is both a drug and a natural component of some dietary supplements. 5-HTP is produced from tryptophan by tryptophan hydroxylase (TPH), which is present in two isoforms (TPH1 and TPH2). Decarboxylation of 5-HTP yields serotonin (5-hydroxytryptamine, 5-HT) that is further transformed to melatonin (N-acetyl-5-methoxytryptamine). 5-HTP plays a major role both in neurologic and metabolic diseases and its synthesis from tryptophan represents the limiting step in serotonin and melatonin biosynthesis. In this review, after an look at the main natural sources of 5-HTP, the chemical analysis and synthesis, biosynthesis and microbial production of 5-HTP by molecular engineering will be described. The physiological effects of 5-HTP are discussed in both animal studies and human clinical trials. The physiological role of 5-HTP in the treatment of depression, anxiety, panic, sleep disorders, obesity, myoclonus and serotonin syndrome are also discussed. 5-HTP toxicity and the occurrence of toxic impurities present in tryptophan and 5-HTP preparations are also discussed.
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Affiliation(s)
- Massimo E Maffei
- Department of Life Sciences and Systems Biology, University of Turin, Via Quarello 15/a, 10135 Turin, Italy
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3
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Betari N, Sahlholm K, Morató X, Godoy-Marín H, Jáuregui O, Teigen K, Ciruela F, Haavik J. Inhibition of Tryptophan Hydroxylases and Monoamine Oxidase-A by the Proton Pump Inhibitor, Omeprazole- In Vitro and In Vivo Investigations. Front Pharmacol 2020; 11:593416. [PMID: 33324221 PMCID: PMC7726444 DOI: 10.3389/fphar.2020.593416] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/16/2020] [Indexed: 01/06/2023] Open
Abstract
Serotonin (5-HT) is a hormone and neurotransmitter that modulates neural activity as well as a wide range of other physiological processes including cardiovascular function, bowel motility, and platelet aggregation. 5-HT synthesis is catalyzed by tryptophan hydroxylase (TPH) which exists as two distinct isoforms; TPH1 and TPH2, which are responsible for peripheral and central 5-HT, respectively. Due to the implication of 5-HT in a number of pathologies, including depression, anxiety, autism, sexual dysfunction, irritable bowel syndrome, inflammatory bowel disease, and carcinoid syndrome, there has been a growing interest in finding modulators of these enzymes in recent years. We thus performed high-throughput screening (HTS) using a fluorescence-based thermal shift assay (DSF) to search the Prestwick Chemical Library containing 1,280 compounds, mostly FDA-approved drugs, for TPH1 binders. We here report the identification of omeprazole, a proton pump inhibitor, as an inhibitor of TPH1 and TPH2 with low micromolar potency and high selectivity over the other aromatic amino acid hydroxylases. The S-enantiomer of omeprazole, esomeprazole, has recently also been described as an inhibitor of monoamine oxidase-A (MAO-A), the main enzyme responsible for 5-HT degradation, albeit with lower potency compared to the effect on TPH1 and TPH2. In order to investigate the net effect of simultaneous inhibition of TPH and MAO-A in vivo, we administered high-dose (100 mg/kg) omeprazole to CD-1 mice for 4 days, after which the animals were subjected to the tail suspension test. Finally, central (whole brain) and peripheral (serum) 5-HT content was measured using liquid chromatography-mass spectrometry (LC-MS). Omeprazole treatment significantly increased 5-HT concentrations, both in brain and in serum, and reduced the time spent immobile in the tail suspension test relative to vehicle control. Thus, the MAO-A inhibition afforded by high-dose omeprazole appears to overcome the opposing effect on 5-HT produced by inhibition of TPH1 and TPH2. Further modification of proton pump inhibitor scaffolds may yield more selective modulators of 5-HT metabolism.
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Affiliation(s)
- Nibal Betari
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Kristoffer Sahlholm
- Department of Integrative Medical Biology, Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden.,Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Xavier Morató
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Héctor Godoy-Marín
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Olga Jáuregui
- Scientific and Technological Centers of University of Barcelona (CCiTUB), Barcelona, Spain
| | - Knut Teigen
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Francisco Ciruela
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Jan Haavik
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Division of Psychiatry, Bergen Center of Brain Plasticity, Haukeland University Hospital, Bergen, Norway
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4
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Discovery and biological characterization of a novel scaffold for potent inhibitors of peripheral serotonin synthesis. Future Med Chem 2020; 12:1461-1474. [DOI: 10.4155/fmc-2020-0127] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Aim: Tryptophan hydroxylase 1 (TPH1) catalyzes serotonin synthesis in peripheral tissues. Selective TPH1 inhibitors may be useful for treating disorders related to serotonin dysregulation. Results & methodology: Screening using a thermal shift assay for TPH1 binders yielded Compound 1 (2-(4-methylphenyl)-1,2-benzisothiazol-3(2 H)-one), which showed high potency (50% inhibition at 98 ± 30 nM) and selectivity for inhibiting TPH over related aromatic amino acid hydroxylases in enzyme activity assays. Structure–activity relationships studies revealed several analogs of 1 showing comparable potency. Kinetic studies suggested a noncompetitive mode of action of 1, with regards to tryptophan and tetrahydrobiopterin. Computational docking studies and live cell assays were also performed. Conclusion: This TPH1 inhibitor scaffold may be useful for developing new therapeutics for treating elevated peripheral serotonin.
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5
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Cheung KM, Yang KA, Nakatsuka N, Zhao C, Ye M, Jung ME, Yang H, Weiss PS, Stojanović MN, Andrews AM. Phenylalanine Monitoring via Aptamer-Field-Effect Transistor Sensors. ACS Sens 2019; 4:3308-3317. [PMID: 31631652 PMCID: PMC6957227 DOI: 10.1021/acssensors.9b01963] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Determination of the amino acid phenylalanine is important for lifelong disease management in patients with phenylketonuria, a genetic disorder in which phenylalanine accumulates and persists at levels that alter brain development and cause permanent neurological damage and cognitive dysfunction. Recent approaches for treating phenylketonuria focus on injectable medications that efficiently break down phenylalanine but sometimes result in detrimentally low phenylalanine levels. We have identified new DNA aptamers for phenylalanine in two formats, initially as fluorescent sensors and then, incorporated with field-effect transistors (FETs). Aptamer-FET sensors detected phenylalanine over a wide range of concentrations (fM to mM). para-Chlorophenylalanine, which inhibits the enzyme that converts phenylalanine to tyrosine, was used to induce hyperphenylalaninemia during brain development in mice. Aptamer-FET sensors were specific for phenylalanine versus para-chlorophenylalanine and differentiated changes in mouse serum phenylalanine at levels expected in patients. Aptamer-FETs can be used to investigate models of hyperphenylalanemia in the presence of structurally related enzyme inhibitors, as well as naturally occurring amino acids. Nucleic acid-based receptors that discriminate phenylalanine analogs, some that differ by a single substituent, indicate a refined ability to identify aptamers with binding pockets tailored for high affinity and specificity. Aptamers of this type integrated into FETs enable rapid, electronic, label-free phenylalanine sensing.
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Affiliation(s)
- Kevin M. Cheung
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Kyung-Ae Yang
- Department of Medicine, Columbia University, New York, New York 10032, United States
| | - Nako Nakatsuka
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Chuanzhen Zhao
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Mao Ye
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Michael E. Jung
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Hongyan Yang
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience & Human Behavior, and Hatos Center for Neuropharmacology, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Paul S. Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Departments of Bioengineering and Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Milan N. Stojanović
- Department of Medicine, Columbia University, New York, New York 10032, United States
- Departments of Biomedical Engineering and Systems Biology, Columbia University, New York, New York 10032, United States
| | - Anne M Andrews
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience & Human Behavior, and Hatos Center for Neuropharmacology, University of California, Los Angeles, Los Angeles, California 90095, United States
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6
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Abstract
The rate-limiting enzyme in serotonin synthesis is tryptophan hydroxylase (TPH). There are two independent serotonin systems in the body characterized by two isoforms of TPH, TPH1 and TPH2. While TPH2 synthesizes serotonin in the brain, TPH1 is expressed in the gut and in other peripheral tissues and supplies platelets in the circulation with serotonin. This duality of the serotonin system is enforced by the blood-brain barrier which is impermeable for serotonin. In the brain serotonin acts as neurotransmitter and is a main target for the treatment of psychiatric disorders. In the periphery it is released by platelets at the site of activation and elicits numerous physiological effects. TPH1 deficient mice were shown to be protected from diverse diseases including hemostatic, inflammatory, fibrotic, gastrointestinal, and metabolic disorders and therefore serotonin synthesis inhibition emerged as a reasonable therapeutic paradigm. Recently the first TPH inhibitor, telotristat ethyl, came on the market for the treatment of carcinoid syndrome. This review summarizes the state of development and the therapeutic opportunities of such compounds.
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Affiliation(s)
- Michael Bader
- Max-Delbrück Center for Molecular Medicine (MDC), Robert-Rössle-Str. 10, 13125 Berlin-Buch, Germany; University of Lübeck, Institute for Biology, Ratzeburger Allee 160, 23562 Lübeck, Germany; Charité University Medicine, Charitéplatz 1, 10117 Berlin, Germany; German Center for Cardiovascular Research (DZHK), Partner Site, Berlin, Germany.
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7
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Scotton WJ, Hill LJ, Williams AC, Barnes NM. Serotonin Syndrome: Pathophysiology, Clinical Features, Management, and Potential Future Directions. Int J Tryptophan Res 2019; 12:1178646919873925. [PMID: 31523132 PMCID: PMC6734608 DOI: 10.1177/1178646919873925] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 08/13/2019] [Indexed: 12/18/2022] Open
Abstract
Serotonin syndrome (SS) (also referred to as serotonin toxicity) is a potentially life-threatening drug-induced toxidrome associated with increased serotonergic activity in both the peripheral (PNS) and central nervous systems (CNS). It is characterised by a dose-relevant spectrum of clinical findings related to the level of free serotonin (5-hydroxytryptamine [5-HT]), or 5-HT receptor activation (predominantly the 5-HT1A and 5-HT2A subtypes), which include neuromuscular abnormalities, autonomic hyperactivity, and mental state changes. Severe SS is only usually precipitated by the simultaneous initiation of 2 or more serotonergic drugs, but the syndrome can also occur after the initiation of a single serotonergic drug in a susceptible individual, the addition of a second or third agent to long-standing doses of a maintenance serotonergic drug, or after an overdose. The combination of a monoamine oxidase inhibitor (MAOI), in particular MAO-A inhibitors that preferentially inhibit the metabolism of 5-HT, with serotonergic drugs is especially dangerous, and may lead to the most severe form of the syndrome, and occasionally death. This review describes our current understanding of the pathophysiology, clinical presentation and management of SS, and summarises some of the drugs and interactions that may precipitate the condition. We also discuss the newer novel psychoactive substances (NPSs), a growing public health concern due to their increased availability and use, and their potential risk to evoke the syndrome. Finally, we discuss whether the inhibition of tryptophan hydroxylase (TPH), in particular the neuronal isoform (TPH2), may provide an opportunity to pharmacologically target central 5-HT synthesis, and so develop new treatments for severe, life-threatening SS.
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Affiliation(s)
- William J Scotton
- Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Lisa J Hill
- Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
| | - Adrian C Williams
- Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Nicholas M Barnes
- Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
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8
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Kulikova EA, Kulikov AV. Tryptophan hydroxylase 2 as a therapeutic target for psychiatric disorders: focus on animal models. Expert Opin Ther Targets 2019; 23:655-667. [PMID: 31216212 DOI: 10.1080/14728222.2019.1634691] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Introduction: Tryptophan hydroxylase 2 (TPH2) is the key, rate-limiting enzyme of serotonin (5-HT) synthesis in the brain. Some polymorphic variants of the human Tph2 gene are associated with psychiatric disorders. Area covered: This review focuses on the mechanisms underlying the association between the TPH2 activity and behavioral disturbances in models of psychiatric disorders. Specifically, it discusses: 1) genetic and posttranslational mechanisms defining the TPH2 activity, 2) behavioral effects of knockout and loss-of-function mutations in the mouse Tph2 gene, 3) pharmacological inhibition and the activation of the TPH2 activity and 4) alterations in the brain TPH2 activity in animal models of psychiatric disorders. We show the dual role of the TPH2 activity: both deficit and excess of the TPH2 activity cause significant behavioral disturbances in animal models of depression, anxiety, aggression, obsessive-compulsive disorders, schizophrenia, and catalepsy. Expert opinion: Pharmacological chaperones correcting the structure of the TPH2 molecule are promising tools for treatment of some hereditary psychiatric disorders caused by loss-of-function mutations in the human Tph2 gene; while some stress-induced affective disorders, associated with the elevated TPH2 activity, may be effectively treated by TPH2 inhibitors. This dual role of TPH2 should be taken into consideration during therapy of psychiatric disorders.
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Affiliation(s)
- Elizabeth A Kulikova
- a Federal Research Center Institute of Cytology and Genetics , Siberian Division of the Russian Academy of Science , Novosibirsk , Russia
| | - Alexander V Kulikov
- a Federal Research Center Institute of Cytology and Genetics , Siberian Division of the Russian Academy of Science , Novosibirsk , Russia
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9
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Matthes S, Bader M. Peripheral Serotonin Synthesis as a New Drug Target. Trends Pharmacol Sci 2018; 39:560-572. [PMID: 29628275 DOI: 10.1016/j.tips.2018.03.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 12/19/2022]
Abstract
The first step in serotonin (5-HT) biosynthesis is catalyzed by tryptophan hydroxylase (TPH). There are two independent sources of the monoamine that have distinct functions: first, the TPH1-expressing enterochromaffin cells (ECs) of the gut; second, TPH2-expressing serotonergic neurons. TPH1-deficient mice revealed that peripheral 5-HT plays important roles in platelet function and in inflammatory and fibrotic diseases of gut, pancreas, lung, and liver. Therefore, TPH inhibitors were developed which cannot pass the blood-brain barrier to specifically block peripheral 5-HT synthesis. They showed therapeutic efficacy in several rodent disease models, and telotristat ethyl is the first TPH inhibitor to be approved for the treatment of carcinoid syndrome. We review this development and discuss further therapeutic options for these compounds.
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Affiliation(s)
- Susann Matthes
- Max-Delbrück Center for Molecular Medicine (MDC), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany; University of Lübeck, Institute for Biology, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Michael Bader
- Max-Delbrück Center for Molecular Medicine (MDC), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany; University of Lübeck, Institute for Biology, Ratzeburger Allee 160, 23562 Lübeck, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch-Straße 2, 10178 Berlin, Germany; Charité University Medicine, Charitéplatz 1, 10117 Berlin, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany.
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10
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Discovery of spirocyclic proline tryptophan hydroxylase-1 inhibitors. Bioorg Med Chem Lett 2016; 26:1124-9. [DOI: 10.1016/j.bmcl.2016.01.064] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 01/18/2016] [Accepted: 01/21/2016] [Indexed: 12/18/2022]
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11
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O'Leary RE, Shih JC, Hyland K, Kramer N, Asher YJT, Graham JM. De novo microdeletion of Xp11.3 exclusively encompassing the monoamine oxidase A and B genes in a male infant with episodic hypotonia: a genomics approach to personalized medicine. Eur J Med Genet 2012; 55:349-53. [PMID: 22365943 DOI: 10.1016/j.ejmg.2012.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 01/01/2012] [Indexed: 02/07/2023]
Abstract
Monoamine oxidase A and B (MAOA and MAOB) play key roles in deaminating neurotransmitters and various other biogenic amines. Patients deficient in one or both enzymes have distinct metabolic and neurologic profiles. MAOB deficient patients exhibit normal clinical characteristics and behavior, while MAOA deficient patients have borderline intellectual deficiency and impaired impulse control. Patients who lack both MAOA and MAOB have the most extreme laboratory values (urine, blood, and CSF serotonin 4-6 times normal, with elevated O-methylated amine metabolites and reduced deaminated metabolites) in addition to severe intellectual deficiency and behavioral problems. Mice lacking maoa and moab exhibit decreased proliferation of neural stem cells beginning in late gestation and persisting into adulthood. These mice show significantly increased monoamine levels, particularly serotonin, as well as anxiety-like behaviors as adults, suggesting that brain maturation in late embryonic development is adversely affected by elevated serotonin levels. We report the case of a male infant with a de novo Xp11.3 microdeletion exclusively encompassing the MAOA and MAOB genes. This newly recognized X-linked disorder is characterized by severe intellectual disability and unusual episodes of hypotonia, which resemble atonic seizures, but have no EEG correlate. A customized low dietary amine diet was implemented in an attempt to prevent the cardiovascular complications that can result from the excessive intake of these compounds. This is the second report of this deletion and the first attempt to maintain the patient's cardiovascular health through dietary manipulation. Even though a diet low in tyramine, phenylethylamine, and dopa/dopamine is necessary for long-term management, it will not rescue the abnormal monoamine profile seen in combined MAOA and MAOB deficiency. Our patient displays markedly elevated levels of serotonin in blood, serum, urine, and CSF while on this diet. Serotonin biosynthesis inhibitors like para-chlorophenylalanine and p-ethynylphenylalanine may be needed to lower serotonin levels in patients with absent monoamine oxidase enzymes.
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Affiliation(s)
- Ryan E O'Leary
- Medical Genetics Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
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12
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Thonon D, Kech C, Paris J, Lemaire C, Luxen A. New strategy for the preparation of clickable peptides and labeling with 1-(azidomethyl)-4-[(18)F]-fluorobenzene for PET. Bioconjug Chem 2009; 20:817-23. [PMID: 19323495 DOI: 10.1021/bc800544p] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The alkyne-azide Cu(I)-catalyzed Huisgen cycloaddition, a click type reaction was used to label a peptide with fluorine-18. A novel solid phase synthesis approach for the preparation of clickable peptides has been developed and has also permitted the straightforward preparation of reference compounds. A complementary azide labeling agent (1-(azidomethyl)-4-[(18)F]-fluorobenzene) has been produced in a four step procedure in 75 min with a 34% radiochemical yield (decay corrected). Conjugation of [(18)F]fluoroazide with a model alkyne-neuropeptide produced the desired (18)F-radiolabeled peptide in less than 15 min with a yield of 90% and excellent radiochemical purity.
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Affiliation(s)
- David Thonon
- Cyclotron Research Center, Liege University, Belgium.
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13
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Effects of amyloid-β peptides on the serotoninergic 5-HT1A receptors in the rat hippocampus. Neurobiol Aging 2009; 32:103-14. [PMID: 19249128 DOI: 10.1016/j.neurobiolaging.2009.01.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2008] [Revised: 12/29/2008] [Accepted: 01/15/2009] [Indexed: 01/07/2023]
Abstract
A recent [(18)F]MPPF-positron emission tomography study has highlighted an overexpression of 5-HT(1A) receptors in the hippocampus of patients with mild cognitive impairment compared to a decrease in those with Alzheimer's disease (AD) [Truchot, L., Costes, S.N., Zimmer, L., Laurent, B., Le Bars, D., Thomas-Antérion, C., Croisile, B., Mercier, B., Hermier, M., Vighetto, A., Krolak-Salmon, P., 2007. Up-regulation of hippocampal serotonin metabolism in mild cognitive impairment. Neurology 69 (10), 1012-1017]. We used in vivo and in vitro neuroimaging to evaluate the longitudinal effects of injecting amyloid-β (Aβ) peptides (1-40) into the dorsal hippocampus of rats. In vivo microPET imaging showed no significant change in [(18)F]MPPF binding in the dorsal hippocampus over time, perhaps due to spatial resolution. However, in vitro autoradiography with [(18)F]MPPF (which is antagonist) displayed a transient increase in 5-HT(1A) receptor density 7 days after Aβ injection, whereas [(18)F]F15599 (a radiolabelled 5-HT(1A) agonist) binding was unchanged suggesting that the overexpressed 5-HT(1A) receptors were in a non-functional state. Complementary histology revealed a loss of glutamatergic neurons and an intense astroglial reaction at the injection site. Although a neurogenesis process cannot be excluded, we propose that Aβ injection leads to a transient astroglial overexpression of 5-HT(1A) receptors in compensation for the local neuronal loss. Exploration of the functional consequences of these serotoninergic modifications during the neurodegenerative process may have an impact on therapeutics targeting 5-HT(1A) receptors in AD.
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14
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Parrot S, Lambás-Señas L, Sentenac S, Denoroy L, Renaud B. Highly sensitive assay for the measurement of serotonin in microdialysates using capillary high-performance liquid chromatography with electrochemical detection. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 850:303-9. [PMID: 17166782 DOI: 10.1016/j.jchromb.2006.11.045] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Revised: 11/15/2006] [Accepted: 11/28/2006] [Indexed: 11/23/2022]
Abstract
A highly sensitive isocratic capillary high-performance liquid chromatographic (HPLC) method with electrochemical detection (ED) for the simultaneous measurement of serotonin (5-hydroxytryptamine, 5-HT) and its metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) in microdialysates has been developed using a 0.5 mm i.d. capillary column and a 11-nL detection cell. This method, validated on both pharmacological and analytical bases, can be performed using injection volumes as low as 1 microL. The limits of detection were 5.6 x 10(-11)mol/L and 3.0 x 10(-9)mol/L for 5-HT and 5-HIAA. Several applications of the present method are given on microdialysates from rodent brain and human spinal cord.
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Affiliation(s)
- Sandrine Parrot
- NEUROCHEM, Institut Fédératif des Neurosciences de Lyon, Plate-forme de Physiologie, Université Lyon 1, France.
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Peters EJ, Slager SL, McGrath PJ, Knowles JA, Hamilton SP. Investigation of serotonin-related genes in antidepressant response. Mol Psychiatry 2004; 9:879-89. [PMID: 15052272 DOI: 10.1038/sj.mp.4001502] [Citation(s) in RCA: 180] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this study, we sought out to test the hypothesis that genetic factors may influence antidepressant response to fluoxetine. The investigation focused on seven candidate genes in the serotonergic pathway involved in the synthesis, transport, recognition, and degradation of serotonin. Our clinical sample consisted of 96 subjects with unipolar major depression treated with fluoxetine with response variables assessed after a 12-week trial. Patient data were also collected to investigate the pattern of drug response. Using a high-throughput single-nucleotide polymorphism (SNP) genotyping platform and capillary electrophoresis, we genotyped patients at 110 SNPs and four repeat polymorphisms located in seven candidate genes (HTR1A, HTR2A, HTR2C, MAOA, SLC6A4, TPH1, and TPH2). Statistical tests performed included single-locus and haplotype association tests, and linkage disequilibrium (LD) estimation. Little evidence of population stratification was observed in the sample with 20 random SNPs using a genomic control procedure. Our most intriguing result involved three SNPs in the TPH1 gene and one SNP in the SLC6A4 gene, which show significant single-locus association when response to fluoxetine is compared to nonresponse (P=0.02-0.04). All odds ratios indicated an increased risk of not responding to fluoxetine. In the specific response vs nonspecific and nonresponse comparison, three SNPs in the TPH2 gene (P=0.02-0.04) were positively associated and one SNP in the HTR2A gene (P=0.02) was negatively associated. When comparing specific response to nonspecific response, we found significant negative associations in three SNPs in the HTR2A gene (P=0.001-0.03) and two SNPs in the MAOA gene (P=0.03-0.05). We observed variable, although strong LD, in each gene and unexpectedly low numbers of estimated haplotypes, formed from tagged SNPs. Significant haplotype associations were found in all but the HTR1A and HTR2C genes. Although these data should be interpreted cautiously due to the small sample size, these results implicate TPH1 and SLC6A4 in general response, and HTR2A, TPH2, and MAOA in the specificity of response to fluoxetine. Intriguingly, we observe that a number of the less frequent alleles of many of the SNP markers were associated with the nonresponse and nonspecific phenotypes.
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Affiliation(s)
- E J Peters
- Department of Psychiatry, University of California, San Francisco, CA 94143-0984, USA
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