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Boutin JA, Kennaway DJ, Jockers R. Melatonin: Facts, Extrapolations and Clinical Trials. Biomolecules 2023; 13:943. [PMID: 37371523 DOI: 10.3390/biom13060943] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/30/2023] [Accepted: 05/31/2023] [Indexed: 06/29/2023] Open
Abstract
Melatonin is a fascinating molecule that has captured the imagination of many scientists since its discovery in 1958. In recent times, the focus has changed from investigating its natural role as a transducer of biological time for physiological systems to hypothesized roles in virtually all clinical conditions. This goes along with the appearance of extensive literature claiming the (generally) positive benefits of high doses of melatonin in animal models and various clinical situations that would not be receptor-mediated. Based on the assumption that melatonin is safe, high doses have been administered to patients, including the elderly and children, in clinical trials. In this review, we critically review the corresponding literature, including the hypotheses that melatonin acts as a scavenger molecule, in particular in mitochondria, by trying not only to contextualize these interests but also by attempting to separate the wheat from the chaff (or the wishful thinking from the facts). We conclude that most claims remain hypotheses and that the experimental evidence used to promote them is limited and sometimes flawed. Our review will hopefully encourage clinical researchers to reflect on what melatonin can and cannot do and help move the field forward on a solid basis.
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Affiliation(s)
- J A Boutin
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, University of Normandy, INSERM U1239, 76000 Rouen, France
| | - D J Kennaway
- Robinson Research Institute and Adelaide School of Medicine, University of Adelaide, Adelaide Health and Medical Science Building, North Terrace, Adelaide, SA 5006, Australia
| | - R Jockers
- Institut Cochin, Université Paris Cité, INSERM, CNRS, 75014 Paris, France
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2
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Eremeev RO, Beznos OV, Efremov AM, Chesnokova NB, Lozinskaya NA. The rational design of novel 5-amino-2-oxindole derivatives with antiglaucomic activity. Bioorg Med Chem Lett 2023; 90:129334. [PMID: 37207847 DOI: 10.1016/j.bmcl.2023.129334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/02/2023] [Accepted: 05/15/2023] [Indexed: 05/21/2023]
Abstract
Compounds with a 2-oxindole scaffold play an important role in organic synthesis and especially in the synthesis of bioactive organic compounds, therefore, the development of new methods for modifying this scaffold is a very interesting and urgent task. In the framework of this study, we have created a rational approach to the synthesis of 5-amino-substituted derivatives of 2-oxindole. The approach is characterized by good total yield and a small number of steps. One-stage modification of obtained 5-amino-2-oxindoles leads to compounds with promising antiglaucomic activity. The most active compound 7a reduce intraocular pressure by 24% in normotensive rabbits (18% for reference drug timolol).
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Affiliation(s)
- Roman O Eremeev
- Department of Chemistry, Lomonosov Moscow State University, 119992 Moscow, Russian Federation
| | - Olga V Beznos
- Federal State Institute ''Helmholtz Moscow Research Institute of Eye Diseases" of the Russian Federation Ministry of Health, Moscow, Russian Federation
| | - Alexander M Efremov
- Department of Chemistry, Lomonosov Moscow State University, 119992 Moscow, Russian Federation
| | - Natalia B Chesnokova
- Federal State Institute ''Helmholtz Moscow Research Institute of Eye Diseases" of the Russian Federation Ministry of Health, Moscow, Russian Federation
| | - Natalia A Lozinskaya
- Department of Chemistry, Lomonosov Moscow State University, 119992 Moscow, Russian Federation
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3
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Sun W, Liu S, Huang X, Yuan R, Yu J. Cytokine storms and pyroptosis are primarily responsible for the rapid death of mice infected with pseudorabies virus. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210296. [PMID: 34457338 PMCID: PMC8385338 DOI: 10.1098/rsos.210296] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
Pseudorabies virus (PRV), the causative agent of Aujeszky's disease, is one of the most harmful pathogens to the pig industry. PRV can infect and kill a variety of mammals. Nevertheless, the underlying pathogenesis related to PRV is still unclear. This study aims to investigate the pathogenesis induced by PRV in a mouse model. The mice infected with the PRV-HLJ strain developed severe clinical manifestations at 36 h post-infection (hpi), and mortality occurred within 48-72 hpi. Hematoxylin-eosin staining and qRT-PCR methods were used to detect the pathological damage and expression of cytokines related to an immune reaction in brain tissue, respectively. The cytokine storms caused by IFN-α, IFN-β, TNF-α, IL-1β, IL-6 and IL-18 were related to the histopathological changes induced by PRV. This pattern of cytokine secretion depicts an image of typical cytokine storms, characterized by dysregulated secretion of pro-inflammatory cytokines and imbalanced pro-inflammatory and anti-inflammatory responses. In addition, the pyroptosis pathway was also activated by PRV by elevating the expression levels of nod-like receptor protein 3, Caspase-1, Gasdermin-D and interleukin-1β/18. These findings provide a way for further understanding the molecular basis in PRV pathogenesis.
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Affiliation(s)
- Wei Sun
- College of Agriculture, Tongren Polytechnic College, Bijiang District, Tongren City, Guizhou 554300, People's Republic of China
| | - Shanshan Liu
- College of Agriculture, Tongren Polytechnic College, Bijiang District, Tongren City, Guizhou 554300, People's Republic of China
- National and Local Engineering Research Centre for Separation and Purification Ethnic Chinese Veterinary Herbs, Tongren City, Guizhou 554300, People's Republic of China
| | - Xuefei Huang
- College of Agriculture, Tongren Polytechnic College, Bijiang District, Tongren City, Guizhou 554300, People's Republic of China
| | - Rui Yuan
- College of Agriculture, Tongren Polytechnic College, Bijiang District, Tongren City, Guizhou 554300, People's Republic of China
- National and Local Engineering Research Centre for Separation and Purification Ethnic Chinese Veterinary Herbs, Tongren City, Guizhou 554300, People's Republic of China
| | - Jiansheng Yu
- College of Agriculture, Tongren Polytechnic College, Bijiang District, Tongren City, Guizhou 554300, People's Republic of China
- National and Local Engineering Research Centre for Separation and Purification Ethnic Chinese Veterinary Herbs, Tongren City, Guizhou 554300, People's Republic of China
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Cecon E, Legros C, Boutin JA, Jockers R. Journal of pineal research guideline for authors: Defining and characterizing melatonin targets. J Pineal Res 2021; 70:e12712. [PMID: 33332653 DOI: 10.1111/jpi.12712] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/04/2020] [Accepted: 12/05/2020] [Indexed: 12/15/2022]
Abstract
A multitude of effects has been attributed to melatonin at pmol/L to mmol/L concentrations. More than fifteen targets have been proposed for melatonin but only few of them are well characterized. The current guidelines intend to provide a framework to improve and rationalize the characterization of melatonin targets and effects. They should be considered as mandatory guidelines and minimum requirements for manuscripts submitted to the Journal of Pineal Research.
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Affiliation(s)
- Erika Cecon
- Institut Cochin, CNRS, INSERM, Université de Paris, Paris, France
| | - Céline Legros
- Institut de Recherches SERVIER, Croissy-sur-Seine, France
| | - Jean A Boutin
- Institut de Recherches SERVIER, Croissy-sur-Seine, France
| | - Ralf Jockers
- Institut Cochin, CNRS, INSERM, Université de Paris, Paris, France
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5
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Janda E, Nepveu F, Calamini B, Ferry G, Boutin JA. Molecular Pharmacology of NRH:Quinone Oxidoreductase 2: A Detoxifying Enzyme Acting as an Undercover Toxifying Enzyme. Mol Pharmacol 2020; 98:620-633. [DOI: 10.1124/molpharm.120.000105] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/11/2020] [Indexed: 01/02/2023] Open
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An insight into the scientific background and future perspectives for the potential uses of melatonin. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.ejbas.2015.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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viviD D, Bentley GE. Seasonal Reproduction in Vertebrates: Melatonin Synthesis, Binding, and Functionality Using Tinbergen's Four Questions. Molecules 2018; 23:E652. [PMID: 29534047 PMCID: PMC6017951 DOI: 10.3390/molecules23030652] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/11/2018] [Accepted: 02/13/2018] [Indexed: 12/15/2022] Open
Abstract
One of the many functions of melatonin in vertebrates is seasonal reproductive timing. Longer nights in winter correspond to an extended duration of melatonin secretion. The purpose of this review is to discuss melatonin synthesis, receptor subtypes, and function in the context of seasonality across vertebrates. We conclude with Tinbergen's Four Questions to create a comparative framework for future melatonin research in the context of seasonal reproduction.
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Affiliation(s)
- Dax viviD
- Berkeley Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
| | - George E Bentley
- Berkeley Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
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Mayo JC, Sainz RM, González-Menéndez P, Hevia D, Cernuda-Cernuda R. Melatonin transport into mitochondria. Cell Mol Life Sci 2017; 74:3927-3940. [PMID: 28828619 PMCID: PMC11107582 DOI: 10.1007/s00018-017-2616-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/03/2017] [Indexed: 12/15/2022]
Abstract
Melatonin is a well-known, nighttime-produced indole found in bacteria, eukaryotic unicellulars, animals or vascular plants. In vertebrates, melatonin is the major product of the pineal gland, which accounts for its increase in serum during the dark phase, but it is also produced by many other organs and cell types. Such a wide distribution is consistent with its multiple and well-described functions which include from the circadian regulation and adaptation to seasonal variations to immunomodulatory and oncostatic actions in different types of tumors. The discovery of its antioxidant properties in the early 1990s opened a new field of potential protective functions in multiple tissues. A special mention should be made regarding the nervous system, where the indole is considered a major neuroprotector. Furthermore, mitochondria appear as one of the most important targets for the indole's protective actions. Melatonin's mechanisms of action vary from the direct molecular interaction with free radicals (free radical scavenger) to the binding to membrane (MLT1A and MLT1B) or nuclear receptors (RZR/RORα). Receptor binding has been associated with some, but not all of the indole functions reported to date. Recently, two new mechanisms of cellular uptake involving the facilitative glucose transporters GLUT/SLC2A and the proton-driven oligopeptide transporter PEPT1/2 have been reported. Here we discuss the potential importance that these newly discovered transport systems could have in determining the actions of melatonin, particularly in the mitochondria. We also argue the relative importance of passive diffusion vs active transport in different parts of the cell.
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Affiliation(s)
- Juan C Mayo
- Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, C/Julián Clavería, 6, 33006, Oviedo, Asturias, Spain.
- Instituto Universitario Oncológico del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain.
| | - Rosa M Sainz
- Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, C/Julián Clavería, 6, 33006, Oviedo, Asturias, Spain
- Instituto Universitario Oncológico del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - Pedro González-Menéndez
- Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, C/Julián Clavería, 6, 33006, Oviedo, Asturias, Spain
- Instituto Universitario Oncológico del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - David Hevia
- Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, C/Julián Clavería, 6, 33006, Oviedo, Asturias, Spain
- Instituto Universitario Oncológico del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - Rafael Cernuda-Cernuda
- Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, C/Julián Clavería, 6, 33006, Oviedo, Asturias, Spain
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Jaworek J, Leja-Szpak A, Nawrot-Porąbka K, Szklarczyk J, Kot M, Pierzchalski P, Góralska M, Ceranowicz P, Warzecha Z, Dembinski A, Bonior J. Effects of Melatonin and Its Analogues on Pancreatic Inflammation, Enzyme Secretion, and Tumorigenesis. Int J Mol Sci 2017; 18:ijms18051014. [PMID: 28481310 PMCID: PMC5454927 DOI: 10.3390/ijms18051014] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 04/26/2017] [Accepted: 05/02/2017] [Indexed: 12/14/2022] Open
Abstract
Melatonin is an indoleamine produced from the amino acid l-tryptophan, whereas metabolites of melatonin are known as kynuramines. One of the best-known kynuramines is N1-acetyl-N1-formyl-5-methoxykynuramine (AFMK). Melatonin has attracted scientific attention as a potent antioxidant and protector of tissue against oxidative stress. l-Tryptophan and kynuramines share common beneficial features with melatonin. Melatonin was originally discovered as a pineal product, has been detected in the gastrointestinal tract, and its receptors have been identified in the pancreas. The role of melatonin in the pancreatic gland is not explained, however several arguments support the opinion that melatonin is probably implicated in the physiology and pathophysiology of the pancreas. (1) Melatonin stimulates pancreatic enzyme secretion through the activation of entero-pancreatic reflex and cholecystokinin (CCK) release. l-Tryptophan and AFMK are less effective than melatonin in the stimulation of pancreatic exocrine function; (2) Melatonin is a successful pancreatic protector, which prevents the pancreas from developing of acute pancreatitis and reduces pancreatic damage. This effect is related to its direct and indirect antioxidant action, to the strengthening of immune defense, and to the modulation of apoptosis. Like melatonin, its precursor and AFMK are able to mimic its protective effect, and it is commonly accepted that all these substances create an antioxidant cascade to intensify the pancreatic protection and acinar cells viability; (3) In pancreatic cancer cells, melatonin and AFMK activated a signal transduction pathway for apoptosis and stimulated heat shock proteins. The role of melatonin and AFMK in pancreatic tumorigenesis remains to be elucidated.
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Affiliation(s)
- Jolanta Jaworek
- Department of Medical Physiology, Faculty of Health Sciences, Jagiellonian University Medical College, 31-126 Kraków, Poland.
| | - Anna Leja-Szpak
- Department of Medical Physiology, Faculty of Health Sciences, Jagiellonian University Medical College, 31-126 Kraków, Poland.
| | - Katarzyna Nawrot-Porąbka
- Department of Medical Physiology, Faculty of Health Sciences, Jagiellonian University Medical College, 31-126 Kraków, Poland.
| | - Joanna Szklarczyk
- Department of Medical Physiology, Faculty of Health Sciences, Jagiellonian University Medical College, 31-126 Kraków, Poland.
| | - Michalina Kot
- Department of Medical Physiology, Faculty of Health Sciences, Jagiellonian University Medical College, 31-126 Kraków, Poland.
| | - Piotr Pierzchalski
- Department of Medical Physiology, Faculty of Health Sciences, Jagiellonian University Medical College, 31-126 Kraków, Poland.
| | - Marta Góralska
- Department of Medical Physiology, Faculty of Health Sciences, Jagiellonian University Medical College, 31-126 Kraków, Poland.
| | - Piotr Ceranowicz
- Department of Physiology, Faculty of Medicine, Jagiellonian University Medical College, 31-531 Kraków, Poland.
| | - Zygmunt Warzecha
- Department of Physiology, Faculty of Medicine, Jagiellonian University Medical College, 31-531 Kraków, Poland.
| | - Artur Dembinski
- Department of Physiology, Faculty of Medicine, Jagiellonian University Medical College, 31-531 Kraków, Poland.
| | - Joanna Bonior
- Department of Medical Physiology, Faculty of Health Sciences, Jagiellonian University Medical College, 31-126 Kraków, Poland.
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Manchester LC, Coto-Montes A, Boga JA, Andersen LPH, Zhou Z, Galano A, Vriend J, Tan DX, Reiter RJ. Melatonin: an ancient molecule that makes oxygen metabolically tolerable. J Pineal Res 2015; 59:403-19. [PMID: 26272235 DOI: 10.1111/jpi.12267] [Citation(s) in RCA: 641] [Impact Index Per Article: 71.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/10/2015] [Indexed: 12/11/2022]
Abstract
Melatonin is remarkably functionally diverse with actions as a free radical scavenger and antioxidant, circadian rhythm regulator, anti-inflammatory and immunoregulating molecule, and as an oncostatic agent. We hypothesize that the initial and primary function of melatonin in photosynthetic cyanobacteria, which appeared on Earth 3.5-3.2 billion years ago, was as an antioxidant. The evolution of melatonin as an antioxidant by this organism was necessary as photosynthesis is associated with the generation of toxic-free radicals. The other secondary functions of melatonin came about much later in evolution. We also surmise that mitochondria and chloroplasts may be primary sites of melatonin synthesis in all eukaryotic cells that possess these organelles. This prediction is made on the basis that mitochondria and chloroplasts of eukaryotes developed from purple nonsulfur bacteria (which also produce melatonin) and cyanobacteria when they were engulfed by early eukaryotes. Thus, we speculate that the melatonin-synthesizing actions of the engulfed bacteria were retained when these organelles became mitochondria and chloroplasts, respectively. That mitochondria are likely sites of melatonin formation is supported by the observation that this organelle contains high levels of melatonin that are not impacted by blood melatonin concentrations. Melatonin has a remarkable array of means by which it thwarts oxidative damage. It, as well as its metabolites, is differentially effective in scavenging a variety of reactive oxygen and reactive nitrogen species. Moreover, melatonin and its metabolites modulate a large number of antioxidative and pro-oxidative enzymes, leading to a reduction in oxidative damage. The actions of melatonin on radical metabolizing/producing enzymes may be mediated by the Keap1-Nrf2-ARE pathway. Beyond its direct free radical scavenging and indirect antioxidant effects, melatonin has a variety of physiological and metabolic advantages that may enhance its ability to limit oxidative stress.
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Affiliation(s)
- Lucien C Manchester
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX, USA
| | - Ana Coto-Montes
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX, USA
| | - Jose Antonio Boga
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX, USA
| | - Lars Peter H Andersen
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX, USA
| | - Zhou Zhou
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX, USA
| | - Annia Galano
- Departamento de Quimica, Universidad Autonoma Metropolitana-Iztapalapa, Mexico DF, Mexico
| | - Jerry Vriend
- Department of Human Anatomy and Cell Biology, University of Manitoba, Winnipeg, MA, Canada
| | - Dun-Xian Tan
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX, USA
| | - Russel J Reiter
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX, USA
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Boutin JA. Quinone reductase 2 as a promising target of melatonin therapeutic actions. Expert Opin Ther Targets 2015; 20:303-17. [DOI: 10.1517/14728222.2016.1091882] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jean A Boutin
- Institut de Recherches SERVIER, Pole d’Expertise Biotechnologie, Chimie & Biologie, 125, chemin de Ronde, 78290 Croissy-sur-Seine, France
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Černyšiov V, Mauricas M, Girkontaite I. Melatonin inhibits granulocyte adhesion to ICAM via MT3/QR2 and MT2 receptors. Int Immunol 2015; 27:599-608. [PMID: 26031343 DOI: 10.1093/intimm/dxv035] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 05/28/2015] [Indexed: 01/20/2023] Open
Abstract
Neutrophils are cells of the innate immune system that first respond and arrive to the site of infection. Melatonin modulates acute inflammatory responses by interfering with leukocyte recruitment. It is known that melatonin modulates granulocyte migration though the endothelial layer thereby acting on the endothelial cell. Here we investigated whether melatonin could modulate granulocyte infiltration by acting directly on granulocytes. Granulocyte infiltration into the peritoneal cavity was investigated in mice kept at normal light/dark conditions and mice kept under constant lighting. To induce migration of neutrophils from the blood into the injury site via the endothelial layer, a bacterial product N-formyl-l-methionyl- l-leucyl- l-phenylalanine (fMLP) was injected into the peritoneal cavity. We found that the number of infiltrated granulocytes during the dark time was lower than that during the light time. It did not depend on circadian time. Moreover, the expression of an adhesion molecule, CD18, on granulocytes, was also lower during the dark time as compared with the light time. We have found that melatonin inhibited fMLP-induced CD18 up-regulation. Importantly, melatonin also inhibited the integrin-mediated granulocyte adhesion to intercellular adhesion molecule-coated plates. This study additionally showed that melatonin receptors MT2 and MT3/quinone reductase 2 (QR2) are expressed on granulocytes. Interestingly, melatonin increases the expression of its MT3/QR2 receptor. The fMLP-mediated CD18 up-regulation was inhibited by melatonin via MT2 receptor and the integrin-mediated granulocyte adhesion was inhibited by melatonin via MT3/QR2 and MT2 receptors. In conclusion, we show that melatonin suppresses granulocyte migration via endothelium by acting directly on granulocytes.
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Affiliation(s)
- Vitalij Černyšiov
- Department of Immunology, State Research Institute Centre for Innovative Medicine, LT-08409 Vilnius, Lithuania
| | - Mykolas Mauricas
- Department of Immunology, State Research Institute Centre for Innovative Medicine, LT-08409 Vilnius, Lithuania
| | - Irute Girkontaite
- Department of Immunology, State Research Institute Centre for Innovative Medicine, LT-08409 Vilnius, Lithuania
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Tan DX, Zheng X, Kong J, Manchester LC, Hardeland R, Kim SJ, Xu X, Reiter RJ. Fundamental issues related to the origin of melatonin and melatonin isomers during evolution: relation to their biological functions. Int J Mol Sci 2014; 15:15858-90. [PMID: 25207599 PMCID: PMC4200856 DOI: 10.3390/ijms150915858] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 08/15/2014] [Accepted: 08/27/2014] [Indexed: 12/29/2022] Open
Abstract
Melatonin and melatonin isomers exist and/or coexist in living organisms including yeasts, bacteria and plants. The levels of melatonin isomers are significantly higher than that of melatonin in some plants and in several fermented products such as in wine and bread. Currently, there are no reports documenting the presence of melatonin isomers in vertebrates. From an evolutionary point of view, it is unlikely that melatonin isomers do not exist in vertebrates. On the other hand, large quantities of the microbial flora exist in the gut of the vertebrates. These microorganisms frequently exchange materials with the host. Melatonin isomers, which are produced by these organisms inevitably enter the host's system. The origins of melatonin and its isomers can be traced back to photosynthetic bacteria and other primitive unicellular organisms. Since some of these bacteria are believed to be the precursors of mitochondria and chloroplasts these cellular organelles may be the primary sites of melatonin production in animals or in plants, respectively. Phylogenic analysis based on its rate-limiting synthetic enzyme, serotonin N-acetyltransferase (SNAT), indicates its multiple origins during evolution. Therefore, it is likely that melatonin and its isomer are also present in the domain of archaea, which perhaps require these molecules to protect them against hostile environments including extremely high or low temperature. Evidence indicates that the initial and primary function of melatonin and its isomers was to serve as the first-line of defence against oxidative stress and all other functions were acquired during evolution either by the process of adoption or by the extension of its antioxidative capacity.
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Affiliation(s)
- Dun-Xian Tan
- Department of Cellular and Structural Biology, the University of Texas, Health Science Center, San Antonio, TX 78229, USA.
| | - Xiaodong Zheng
- Institute for Horticultural Plants, China Agricultural University, Beijing 100083, China.
| | - Jin Kong
- Institute for Horticultural Plants, China Agricultural University, Beijing 100083, China.
| | - Lucien C Manchester
- Department of Cellular and Structural Biology, the University of Texas, Health Science Center, San Antonio, TX 78229, USA.
| | - Ruediger Hardeland
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen 37073, Germany.
| | - Seok Joong Kim
- Department of Cellular and Structural Biology, the University of Texas, Health Science Center, San Antonio, TX 78229, USA.
| | - Xiaoying Xu
- Department of Cellular and Structural Biology, the University of Texas, Health Science Center, San Antonio, TX 78229, USA.
| | - Russel J Reiter
- Department of Cellular and Structural Biology, the University of Texas, Health Science Center, San Antonio, TX 78229, USA.
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Synthetic melatoninergic ligands: achievements and prospects. ISRN BIOCHEMISTRY 2014; 2014:843478. [PMID: 25937968 PMCID: PMC4393004 DOI: 10.1155/2014/843478] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 01/16/2014] [Indexed: 01/17/2023]
Abstract
Pineal hormone melatonin is widely used in the treatment of disorders of circadian rhythms. The presence of melatonin receptors in various animal tissues motivates the use of this hormone in some other diseases. For this reason, in recent years investigators continued the search for synthetic analogues of melatonin which are metabolically stable and selective to receptors. This review includes recent information about the most famous melatonin analogues, their structure, properties, and physiological features of the interaction with melatonin receptors.
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Cutando A, López-Valverde A, DE Vicente J, Gimenez JL, Carcía IA, DE Diego RG. Action of melatonin on squamous cell carcinoma and other tumors of the oral cavity (Review). Oncol Lett 2014; 7:923-926. [PMID: 24944644 PMCID: PMC3961399 DOI: 10.3892/ol.2014.1813] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 12/03/2013] [Indexed: 12/31/2022] Open
Abstract
Melatonin (MLT; N-acetyl-5-metoxy-tryptamine) is a hormone that is principally synthesized in the pineal gland. MLT has been shown to exhibit a variety of functions. The hormone, which is a free radical scavenger, plays an immunomodulatory role, stimulates the proliferation and synthesis of type I collagen and promotes bone formation. Moreover, MLT exerts oncostatic activity through several biological mechanisms, including antiproliferative functions, stimulation of anticancer immunity, modulation of oncogene expression and anti-inflammatory, antioxidant and antiangiogenic effects. In addition, MLT inhibits human cancer cell growth in culture, and previous clinical studies have also confirmed its anticancer properties in vivo. With regard to the underlying mechanisms of MLT in tumor processes, including oral cavity tumors such as epidermoid carcinoma, knowledge of the role played by the MT1 and 2 membrane receptors, MT3 and the calmodulin cytosolic binding sites, as well as the nuclear receptors of the RZR/ROR family, is increasing. It has been hypothesized that exogenous restoration of MT1 (MTNR1A) expression inhibits the growth of oral squamous cell carcinoma cells lacking the expression of the receptor. The tumor suppressing functions of MLT and the presence of the MT1 receptor in various tumors indicate that the receptor may play a pivotal role in oral carcinogenesis. The current review discusses the clinical significance of MLT in oral cancer.
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Affiliation(s)
- Antonio Cutando
- Department of Special Care in Dentistry, School of Dentistry, University of Granada, Granada 18071, Spain
| | - Antonio López-Valverde
- Department of Surgery, School of Dentistry, Faculty of Medicine, University of Salamanca, Salamanca 37007, Spain
| | - Joaquin DE Vicente
- Department of Surgery, School of Dentistry, Faculty of Medicine, University of Salamanca, Salamanca 37007, Spain
| | - Julian López Gimenez
- Department of Special Care in Dentistry, School of Dentistry, University of Granada, Granada 18071, Spain
| | - Isaac Alias Carcía
- Department of Special Care in Dentistry, School of Dentistry, University of Granada, Granada 18071, Spain
| | - Rafael Gomez DE Diego
- Department of Surgery, School of Dentistry, University Alfonso X, Madrid 28691, Spain
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Oxenkrug G. Serotonin-kynurenine hypothesis of depression: historical overview and recent developments. Curr Drug Targets 2013; 14:514-21. [PMID: 23514379 DOI: 10.2174/1389450111314050002] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 03/14/2013] [Accepted: 03/15/2013] [Indexed: 12/17/2022]
Abstract
This mini-review focuses on the studies of late Prof. IP Lapin (1903 - 2012) and his research team on the role of methoxyindole and kynurenine (KYN) pathways of tryptophan (TRP) metabolism in the pathogenesis of depression and action mechanisms of antidepressant effect. In the late 60s of the last century Prof. IP Lapin suggested that "intensification of central serotoninergic processes is a determinant of the thymoleptic (mood elevating) component" while "activation of noradrenergic processes is responsible for psychoenergetic and motor-stimulating component of the clinical antidepressant effect". The cause of serotonin deficiency in depression was attributed to the shunt of TRP "metabolism away from serotonin production towards KYN production" due to cortisol-induced activation of liver enzyme, tryptophan 2,3- dioxygenase, the rate-limiting enzyme of TRP - KYN pathway. Prof. Lapin suggested and discovered that KYN and its metabolites affect brain functions, and proposed the role of neurokynurenines in pathogenesis of depression and action mechanisms of antidepressant effect (kynurenine hypothesis). Further research suggested the antidepressant and cognition- enhancing effects of post-serotonin metabolite, N-acetylserotonin (NAS), an agonist to tyrosine kinase B (TrkB) receptor; and link between depression and chronic inflammation-associated disorders (e.g., insulin resistance, hepatitis C virus) via inflammation-induced activation of indoleamine 2,3- dioxygenase, brain located rate-limiting enzyme of TRY - KYN metabolism. NAS and kynurenines might be the targets for prevention and treatment of depression and associated conditions.
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Affiliation(s)
- Gregory Oxenkrug
- Department of Psychiatry, Tufts University School of Medicine, Director, Psychiatry and Inflammation Program, Tufts Medical Center, Boston, MA 02111, USA.
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Abstract
AbstractMelatonin is a hormone produced by the pineal gland. In addition to its hormonal effect, it has strong antioxidant properties. Melatonin is probably best known for its ability to control circadian rhythm; it is sold in many countries as a supplement or drug for improving of sleep quality. However, melatonin’s effect is not limited to control of circadian rhythm:. it is involved in other effects, including cell cycle control and regulation of several important enzymes, including inhibition of inducible nitric oxide synthase. Melatonin affects immunity as well. It can modulate the immune response on disparate levels with a significant effect on inflammation. The role of melatonin in body regulatory process is not well understood; only limited conclusions can be drawn from known data. The current review attempts to summarize both basic facts about melatonin’s effects and propose research on the lesser known issues in the future.
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A Drug Mystery of Heterocycles: Various Molecules for One Target or One Compound for Multiple Targets? Chem Heterocycl Compd (N Y) 2013. [DOI: 10.1007/s10593-013-1229-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Huang H, Wang Z, Weng SJ, Sun XH, Yang XL. Neuromodulatory role of melatonin in retinal information processing. Prog Retin Eye Res 2013; 32:64-87. [PMID: 22986412 DOI: 10.1016/j.preteyeres.2012.07.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 07/24/2012] [Accepted: 07/25/2012] [Indexed: 12/15/2022]
Affiliation(s)
- Hai Huang
- Institute of Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, PR China
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20
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Lin ZY, Chuang WL. High therapeutic concentration of prazosin up-regulates angiogenic IL6 and CCL2 genes in hepatocellular carcinoma cells. Biomed Pharmacother 2012; 66:583-6. [DOI: 10.1016/j.biopha.2011.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Accepted: 09/06/2011] [Indexed: 11/15/2022] Open
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Dominguez-Rodriguez A, Abreu-Gonzalez P, Arroyo-Ucar E, Reiter RJ. Decreased level of melatonin in serum predicts left ventricular remodelling after acute myocardial infarction. J Pineal Res 2012; 53:319-23. [PMID: 22537272 DOI: 10.1111/j.1600-079x.2012.01001.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
As experimental studies suggest that melatonin is cardioprotective after myocardial infarction (MI), this study sought to investigate the relationships between circulating levels of melatonin and left ventricular (LV) remodelling in patients after acute MI. This prospective study included 161 patients (age 61±3yr; 78% men) undergoing primary percutaneous coronary intervention who were assessed echocardiographically at hospital discharge (day 3-7) and at 12 months. LV remodelling was defined as >20% increase in LV end-diastolic volume at 12-month follow-up compared with baseline. Serum melatonin concentrations were measured at admission, during the light period. Twenty-four patients showed LV remodelling, and 137 had no evidence of LV remodelling. Patients with LV remodelling had lower levels of melatonin at study entry [9.96 (8.28-11.03) versus 16.74 (13.77-19.59) pg/mL, respectively; P <0.0001]. Multivariate analysis showed that melatonin levels (OR=2.10, CI 95% 1.547-2.870, P<0.001) were an independent predictor of LV remodelling at 12-month follow-up. Receiver operating characteristic (ROC) analysis showed an area under the curve of 0.959 (CI 95% 0.93-0.98; P<0.0001). To our knowledge, this is the first study to show the relationship between melatonin and LV remodelling during the chronic phase post-MI.
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López Patiño MA, Guijarro AI, Alonso-Gómez AL, Delgado MJ. Characterization of two different melatonin binding sites in peripheral tissues of the teleost Tinca tinca. Gen Comp Endocrinol 2012; 175:180-7. [PMID: 22134177 DOI: 10.1016/j.ygcen.2011.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 11/08/2011] [Accepted: 11/09/2011] [Indexed: 10/15/2022]
Abstract
The aim of the present study was to localize and characterize 2-iodo-melatonin ([(125)I]Mel) binding sites in peripheral tissues of the teleost Tinca tinca. A wide distribution of [(125)I]Mel binding sites in peripheral locations of the tench is found, with highest densities being measured in the heart, gills and kidney, and low density of [(125)I]Mel binding sites in gastrointestinal tract, spleen, liver and gonads. Saturation, kinetics, and pharmacological approaches revealed the presence of, at least, two different [(125)I]Mel binding sites in the tench peripheral tissues. The unique characterized subtype in the heart fulfils all the criteria for a canonical melatonin receptor belonging to MT(1) family (the binding is saturable, reversible, and inhibited by GTP analogs), and gives support for the presence of a functional melatonin receptor in the heart of the tench. In contrast, kinetic and pharmacological studies in the kidney revealed the preponderance of a melatonin binding site belonging to the MT(3)-like receptor subtype. Moreover, the decrease of specific binding in both, heart and kidney membranes, and the decrease of affinity in the kidney, produced by the addition of a non-hydrolysable GTP analog, and sodium cations suggest the presence of G(i/o)-proteins (that mediate inhibition of cAMP formation) coupled to such melatonin binding sites. Our results also point to different G(i/o)-proteins involved in the underlying mechanism of melatonin binding sites activation in the kidney. Additionally, the kinetics of [(125)I]Mel binding in kidney membrane preparations is a highly thermosensitive process, being necessary to perform the assays at 4 °C since the equilibrium was not reached at 25 °C assay temperature. The time needed to complete association of [(125)I]Mel at such low temperature is only 15s, whereas 100s is required to displace [(125)I]Mel specific binding by the unlabeled melatonin in kidney membranes. Present results support previous reports on melatonin effects in the regulation of different physiological functions in teleost (as cardiovascular physiology and osmoregulation) acting through peripheral specific receptors.
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Affiliation(s)
- M A López Patiño
- Departamento de Fisiología, Fisiología Animal II, Facultad de Biología, Universidad Complutense, 28040 Madrid, Spain
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23
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Cardiac hypertrophy and remodelling: pathophysiological consequences and protective effects of melatonin. J Hypertens 2010; 28 Suppl 1:S7-12. [DOI: 10.1097/01.hjh.0000388488.51083.2b] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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24
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Rosenstein RE, Pandi-Perumal SR, Srinivasan V, Spence DW, Brown GM, Cardinali DP. Melatonin as a therapeutic tool in ophthalmology: implications for glaucoma and uveitis. J Pineal Res 2010; 49:1-13. [PMID: 20492443 DOI: 10.1111/j.1600-079x.2010.00764.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Several lines of evidence support the view that increased free radical generation and altered nitric oxide (NO) metabolism play a role in the pathogenesis of highly prevalent ocular diseases, such as glaucoma and uveitis. Data are discussed indicating that melatonin, being an efficient antioxidant that displays antinitridergic properties, has a promising role in the treatment of these ocular dysfunctions. Melatonin synthesis occurs in the eye of most species, and melatonin receptors are localized in different ocular structures. In view of the fact that melatonin lacks significant adverse collateral effects even at high doses, the application of melatonin could potentially protect ocular tissues by effectively scavenging free radicals and excessive amounts of NO generated in the glaucomatous or uveitic eye.
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Affiliation(s)
- Ruth E Rosenstein
- Department of Human Biochemistry, School of Medicine, CEFyBO, University of Buenos Aires, CONICET, Buenos Aires, Argentina.
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25
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Luchetti F, Canonico B, Betti M, Arcangeletti M, Pilolli F, Piroddi M, Canesi L, Papa S, Galli F. Melatonin signaling and cell protection function. FASEB J 2010; 24:3603-24. [PMID: 20534884 DOI: 10.1096/fj.10-154450] [Citation(s) in RCA: 249] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Besides its well-known regulatory role on circadian rhythm, the pineal gland hormone melatonin has other biological functions and a distinct metabolism in various cell types and peripheral tissues. In different tissues and organs, melatonin has been described to act as a paracrine and also as an intracrine and autocrine agent with overall homeostatic functions and pleiotropic effects that include cell protection and prosurvival factor. These latter effects, documented in a number of in vitro and in vivo studies, are sustained through both receptor-dependent and -independent mechanisms that control detoxification and stress response genes, thus conferring protection against a number of xenobiotics and endobiotics produced by acute and chronic noxious stimuli. Redox-sensitive components are included in the cell protection signaling of melatonin and in the resulting transcriptional response that involves the control of NF-κB, AP-1, and Nrf2. By these pathways, melatonin stimulates the expression of antioxidant and detoxification genes, acting in turn as a glutathione system enhancer. A further and converging mechanism of cell protection by this indoleamine described in different models seems to lie in the control of damage and signaling function of mitochondria that involves decreased production of reactive oxygen species and activation of the antiapoptotic and redox-sensitive element Bcl2. Recent evidence suggests that upstream components in this mitochondrial route include the calmodulin pathway with its central role in melatonin signaling and the survival-promoting component of MAPKs, ERK1/2. In this review article, we will discuss these and other molecular aspects of melatonin signaling relevant to cell protection and survival mechanisms.
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Affiliation(s)
- Francesca Luchetti
- Dipartimento di Scienze Dell’Uomo dell’Ambiente e della Natura, Università degli Studi di Urbino Carlo Bo, Urbino, Italy
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26
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Ferry G, Hecht S, Berger S, Moulharat N, Coge F, Guillaumet G, Leclerc V, Yous S, Delagrange P, Boutin JA. Old and new inhibitors of quinone reductase 2. Chem Biol Interact 2010; 186:103-9. [PMID: 20399199 DOI: 10.1016/j.cbi.2010.04.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 04/02/2010] [Accepted: 04/07/2010] [Indexed: 10/19/2022]
Abstract
Quinone reductase 2 is a cytosolic enzyme which catalyses the reduction of quinones, such as menadione and coenzymes Q. Despite a relatively close sequence-based resemblance to NAD(P)H:quinone oxidoreductase 1 (QR1), it has many different features. QR2 is the third melatonin binding site (MT3). It is inhibited in the micromolar range by melatonin, and does not accept conventional phosphorylated nicotinamides as hydride donors. QR2 has a powerful capacity to activate quinones leading to unexpected toxicity situations. In the present paper, we report the characterization of three QR2 modulators: melatonin, resveratrol and S29434. The latter compound inhibits QR2 activity with an IC(50) in the low nanomolar range. The potency of the modulators ranged as follows, from the least to the most potent: melatonin<resveratrol<S29434. These molecular tools might permit to explore and better understand the relationship existing between QR2 catalytic activity and the various pathological situations in which QR2 has a key role.
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Affiliation(s)
- Gilles Ferry
- Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125, Chemin de Ronde, 78290 Croissy sur Seine, France
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27
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Fatima Sobral Sampaio L, Markus RP. Melatonin and the time window for the expression of the α8 nicotinic acetylcholine receptor in the membrane of chick retinal cells in culture. Int J Dev Neurosci 2010; 28:245-9. [DOI: 10.1016/j.ijdevneu.2010.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2009] [Revised: 01/11/2010] [Accepted: 01/28/2010] [Indexed: 01/15/2023] Open
Affiliation(s)
- Lucia Fatima Sobral Sampaio
- Laboratório de Bioquímica do Desenvolvimento do Sistema Nervoso, Instituto de Ciências Biológicas, Universidade Federal do ParáBelémPABrazil
- Laboratório de CronofarmacologiaDepartamento de FisiologiaInstituto de Biociências, Universidade de São PauloSão PauloSPBrazil
| | - Regina Pekelmann Markus
- Laboratório de CronofarmacologiaDepartamento de FisiologiaInstituto de Biociências, Universidade de São PauloSão PauloSPBrazil
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Abstract
Melatonin (N-acetyl-5-methoxytryptamine) has revealed itself as an ubiquitously distributed and functionally diverse molecule. The mechanisms that control its synthesis within the pineal gland have been well characterized and the retinal and biological clock processes that modulate the circadian production of melatonin in the pineal gland are rapidly being unravelled. A feature that characterizes melatonin is the variety of mechanisms it employs to modulate the physiology and molecular biology of cells. While many of these actions are mediated by well-characterized, G-protein coupled melatonin receptors in cellular membranes, other actions of the indole seem to involve its interaction with orphan nuclear receptors and with molecules, for example calmodulin, in the cytosol. Additionally, by virtue of its ability to detoxify free radicals and related oxygen derivatives, melatonin influences the molecular physiology of cells via receptor-independent means. These uncommonly complex processes often make it difficult to determine specifically how melatonin functions to exert its obvious actions. What is apparent, however, is that the actions of melatonin contribute to improved cellular and organismal physiology. In view of this and its virtual absence of toxicity, melatonin may well find applications in both human and veterinary medicine.
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Alarma-Estrany P, Crooke A, Pintor J. 5-MCA-NAT does not act through NQO2 to reduce intraocular pressure in New-Zealand white rabbit. J Pineal Res 2009; 47:201-209. [PMID: 19627460 DOI: 10.1111/j.1600-079x.2009.00702.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Solid data support the idea that the MT(3) melatonin binding site is an enzyme, quinone reductase 2 (NQO2), rather than a membrane melatonin receptor. However, the melatonin analogue, 5-methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT), reduces intraocular pressure (IOP) via MT(3) melatonin receptors. Therefore, the aim of this work was to test whether the melatonin binding site, MT(3), is indeed the enzyme NQO2 in New Zealand rabbit eyes. To investigate this, the action of several substrates and inhibitors for NQO2 was compared to 5-MCA-NAT in their ability to modify IOP. Also, the effect of 5-MCA-NAT on IOP produced after NQO2 silencing by means of a siRNA was determinated. Altogether, the results led us to conclude that the in vivo effect of the MT(3) ligand 5-MCA-NAT on IOP is not mediated by the enzyme NQO2, suggesting the existence of another melatonin receptor.
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Affiliation(s)
| | | | - Jesús Pintor
- Departamento Bioquímica, E.U. Óptica, Universidad Complutense de Madrid, C/Arcos de Jalón s/n, Madrid, Spain
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Sampaio LDFS. An unexpected effect of 5-MCA-NAT in chick retinal development. Int J Dev Neurosci 2009; 27:511-5. [PMID: 19596433 DOI: 10.1016/j.ijdevneu.2009.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 06/22/2009] [Accepted: 07/01/2009] [Indexed: 10/20/2022] Open
Abstract
Luzindole is an unselective antagonist of the melatonin receptors and melatonin's other binding sites, although some exceptions have been observed in chick retinal neurodevelopment, where this unselective antagonist does not block melatonin's inhibitory effect on the adenylate cyclase enzyme, probably due to the presence of some other melatonin receptor(s) or binding site(s). The present study investigated the modulation of cyclic adenosine 3'-5'-monophosphate (cAMP) levels via MT3 melatonin-binding sites, located within the QR2 (dihydronicotinamide riboside: quinone oxidoreductase 2) enzyme, by observing the response to luzindole. Embryonic and post-hatch retinas, incubated with a selective agonist for the MT3 melatonin-binding site 5-methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT, 10 or 100 nM), had an increase in cAMP accumulation relative to control retinas. Luzindole (5microM) inhibited the 5-MCA-NAT stimulatory effect at all ages tested. The agonist 5-MCA-NAT enhanced the melatonin inhibitory effect on cAMP levels stimulated by forskolin (5microM), but not the stimulatory forskolin effect. The results suggest that MT3 melatonin-binding sites are present in embryonic and post-hatch chick retinas and that luzindole more selectively blocks the 5-MCA-NAT effect on cAMP accumulation than it blocks the melatonin inhibitory effect via G protein-coupled receptors in chick retinal neurodevelopment.
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Affiliation(s)
- Lucia de Fatima Sobral Sampaio
- Laboratório de Bioquímica do Desenvolvimento do Sistema Nervoso, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Corrêa, 1, CEP: 66075-110 Belém, PA, Brazil.
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