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Vringer M, Zhou J, Gool JK, Bijlenga D, Lammers GJ, Fronczek R, Schinkelshoek MS. Recent insights into the pathophysiology of narcolepsy type 1. Sleep Med Rev 2024; 78:101993. [PMID: 39241492 DOI: 10.1016/j.smrv.2024.101993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 08/12/2024] [Accepted: 08/13/2024] [Indexed: 09/09/2024]
Abstract
Narcolepsy type 1 (NT1) is a sleep-wake disorder in which people typically experience excessive daytime sleepiness, cataplexy and other sleep-wake disturbances impairing daily life activities. NT1 symptoms are due to hypocretin deficiency. The cause for the observed hypocretin deficiency remains unclear, even though the most likely hypothesis is that this is due to an auto-immune process. The search for autoantibodies and autoreactive T-cells has not yet produced conclusive evidence for or against the auto-immune hypothesis. Other mechanisms, such as reduced corticotrophin-releasing hormone production in the paraventricular nucleus have recently been suggested. There is no reversive treatment, and the therapeutic approach is symptomatic. Early diagnosis and appropriate NT1 treatment is essential, especially in children to prevent impaired cognitive, emotional and social development. Hypocretin receptor agonists have been designed to replace the attenuated hypocretin signalling. Pre-clinical and clinical trials have shown encouraging initial results. A better understanding of NT1 pathophysiology may contribute to faster diagnosis or treatments, which may cure or prevent it.
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Affiliation(s)
- Marieke Vringer
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Jingru Zhou
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Jari K Gool
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands; Department of Anatomy & Neurosciences, Amsterdam UMC location Vrije Universiteit Amsterdam, Amsterdam, the Netherlands; Compulsivity, Impulsivity and Attention, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Denise Bijlenga
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Gert Jan Lammers
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Rolf Fronczek
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Mink S Schinkelshoek
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands.
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Ming X, Gao S, Sun J, Zhang N, Guo R, Feng X, Luan X, Xing H, Jiao Y, Guo F. Regulation of the MCHergic Neural Circuit to Dorsal Raphe Nucleus on Emotion-Related Behaviors and Intestinal Dysfunction in Mice Model of Irritable Bowel Syndrome with Diarrhea. Neuroendocrinology 2024; 114:605-622. [PMID: 38547853 DOI: 10.1159/000538582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 03/25/2024] [Indexed: 07/10/2024]
Abstract
INTRODUCTION Irritable bowel syndrome with diarrhea (IBS-D) is frequently accompanied by depression and anxiety, resulting in a reduced quality of life and increased medical expenditures. Although psychological factors are known to play an important role in the genesis and development of IBS-D, an understanding of the central neural control of intestinal dysfunction remains elusive. Melanin-concentrating hormone (MCH) is a gut-brain peptide involved in regulating feeding, sleep-wake rhythms, and emotional states. METHODS This study investigated the regulation of the MCHergic neural circuit from the lateral hypothalamic area (LHA) to the dorsal raphe nucleus (DRN) on anxiety- and depression-like behaviors, intestinal motility, and visceral hypersensitivity in a mice model of IBS-D. The models of IBS-D were prepared by inducing chronic unpredictable mild stress. RESULTS Chemogenetic activation of the MCH neurons in the LHA could excite serotonin (5-HT) neurons in the DRN and induce anxiety- and depression-like behaviors and IBS-D-like symptoms, which could be recovered by microinjection of the MCH receptor antagonist SNAP94847 into the DRN. The mice model of IBS-D showed a reduction of 5-HT and brain-derived neurotrophic factor (BDNF) expression in the DRN, while an elevation of 5-HT and BDNF was observed in the colon through immunofluorescent staining, ELISA, and Western blot analysis. SNAP94847 treatment in the DRN alleviated anxiety- and depression-like behaviors, improved intestinal motility, and alleviated visceral hypersensitivity responses by normalizing the 5-HT and BDNF expression in the DRN and colon. CONCLUSION This study suggests that the activation of MCH neurons in the LHA may induce IBS-D symptoms via the DRN and that the MCH receptor antagonist could potentially have therapeutic effects.
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Affiliation(s)
- Xing Ming
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Shengli Gao
- Biomedical Center, Qingdao Medical College, Qingdao University, Qingdao, China
| | - Jinqiu Sun
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Nana Zhang
- Department of Clinical Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Ruixiao Guo
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xufei Feng
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xinchi Luan
- Qingdao Medical College, Qingdao University, Qingdao, China
| | - Han Xing
- Qingdao Medical College, Qingdao University, Qingdao, China
| | - Yang Jiao
- Qingdao Medical College, Qingdao University, Qingdao, China
| | - Feifei Guo
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
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Pintwala SK, Peever J. Brain Circuits Underlying Narcolepsy. Neuroscientist 2023; 29:751-766. [PMID: 34704497 DOI: 10.1177/10738584211052263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Narcolepsy is a sleep disorder manifesting symptoms such as excessive daytime sleepiness and often cataplexy, a sudden and involuntary loss of muscle activity during wakefulness. The underlying neuropathological basis of narcolepsy is the loss of orexin neurons from the lateral hypothalamus. To date numerous animal models of narcolepsy have been produced in the laboratory, being invaluable tools for delineating the brain circuits of narcolepsy. This review will examine the evidence regarding the function of the orexin system, and how loss of this wake-promoting system manifests in excessive daytime sleepiness. This review will also outline the brain circuits controlling cataplexy, focusing on the contribution of orexin signaling loss in narcolepsy. Although our understanding of the brain circuits of narcolepsy has made great progress in recent years, much remains to be understood.
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Affiliation(s)
| | - John Peever
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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Vetrivelan R, Bandaru SS. Neural Control of REM Sleep and Motor Atonia: Current Perspectives. Curr Neurol Neurosci Rep 2023; 23:907-923. [PMID: 38060134 DOI: 10.1007/s11910-023-01322-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2023] [Indexed: 12/08/2023]
Abstract
PURPOSE OF REVIEW Since the formal discovery of rapid eye movement (REM) sleep in 1953, we have gained a vast amount of knowledge regarding the specific populations of neurons, their connections, and synaptic mechanisms regulating this stage of sleep and its accompanying features. This article discusses REM sleep circuits and their dysfunction, specifically emphasizing recent studies using conditional genetic tools. RECENT FINDINGS Sublaterodorsal nucleus (SLD) in the dorsolateral pons, especially the glutamatergic subpopulation in this region (SLDGlut), are shown to be indispensable for REM sleep. These neurons appear to be single REM generators in the rodent brain and may initiate and orchestrate all REM sleep events, including cortical and hippocampal activation and muscle atonia through distinct pathways. However, several cell groups in the brainstem and hypothalamus may influence SLDGlut neuron activity, thereby modulating REM sleep timing, amounts, and architecture. Damage to SLDGlut neurons or their projections involved in muscle atonia leads to REM behavior disorder, whereas the abnormal activation of this pathway during wakefulness may underlie cataplexy in narcolepsy. Despite some opposing views, it has become evident that SLDGlut neurons are the sole generators of REM sleep and its associated characteristics. Further research should prioritize a deeper understanding of their cellular, synaptic, and molecular properties, as well as the mechanisms that trigger their activation during cataplexy and make them susceptible in RBD.
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Affiliation(s)
- Ramalingam Vetrivelan
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, USA.
| | - Sathyajit Sai Bandaru
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, USA
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Koyama Y. The role of orexinergic system in the regulation of cataplexy. Peptides 2023; 169:171080. [PMID: 37598758 DOI: 10.1016/j.peptides.2023.171080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/06/2023] [Accepted: 08/18/2023] [Indexed: 08/22/2023]
Abstract
Loss of orexin/hypocretin causes serious sleep disorder; narcolepsy. Cataplexy is the most striking symptom of narcolepsy, characterized by abrupt muscle paralysis induced by emotional stimuli, and has been considered pathological activation of REM sleep atonia system. Clinical treatments for cataplexy/narcolepsy and early pharmacological studies in narcoleptic dogs tell us about the involvement of monoaminergic and cholinergic systems in the control of cataplexy/narcolepsy. Muscle atonia may be induced by activation of REM sleep-atonia generating system in the brainstem. Emotional stimuli may be processed in the limbic systems including the amygdala, nucleus accumbens, and medial prefrontal cortex. It is now considered that orexin/hypocretin prevents cataplexy by modulating the activity of different points of cataplexy-inducing circuit, including monoaminergic/cholinergic systems, muscle atonia-generating systems, and emotion-related systems. This review will describe the recent advances in understanding the neural mechanisms controlling cataplexy, with a focus on the involvement of orexin/hypocretin system, and will discuss future experimental strategies that will lead to further understanding and treatment of this disease.
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Affiliation(s)
- Yoshimasa Koyama
- Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanaya-gawa, Fukushima 960-1296, Japan..
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6
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Abad VC. Pharmacological options for narcolepsy: are they the way forward? Expert Rev Neurother 2023; 23:819-834. [PMID: 37585269 DOI: 10.1080/14737175.2023.2249234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 08/13/2023] [Accepted: 08/14/2023] [Indexed: 08/18/2023]
Abstract
INTRODUCTION Narcolepsy is an under-recognized, rare neurologic disorder of hypersomnolence that is associated with increased mortality and medical and psychiatric co-morbidities. Narcolepsy exerts a substantial economic burden on patients and society. There is currently no cure, and life-long symptomatic therapy is needed. Available drugs do not modify the disease course. AREAS COVERED This manuscript provides an overview of narcolepsy symptoms, diagnosis, pathophysiology, current pharmacotherapies, and emerging treatments. Gaps and unresolved issues in diagnosis and management of narcolepsy are discussed to answer whether pharmacological options are the way forward. EXPERT OPINION Diagnostic criteria for narcolepsy (ICSD-3) need revision and greater clarity. Improved recognition of cataplexy and other symptoms through educational outreach, new biomarkers, improved test scoring through artificial intelligence algorithms, and use of machine learning may facilitate earlier diagnosis and treatment. Pharmacological options need improved symptomatic therapy in addition to targeted therapies that address the loss of hypocretin signaling. Optimal narcolepsy care also needs a better understanding of the pathophysiology, recognition of the different phenotypes in narcolepsy, identification of at-risk individuals and early recognition of symptoms, better diagnostic tools, and a database for research and disease monitoring of treatment, side-effects, and comorbidities.
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Affiliation(s)
- Vivien C Abad
- Division of Sleep Medicine, Department of Psychiatry and Behavioral Sciences Stanford University, Redwood, CA, USA
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Traut J, Mengual JP, Meijer EJ, McKillop LE, Alfonsa H, Hoerder-Suabedissen A, Song SH, Fehér KD, Riemann D, Molnar Z, Akerman CJ, Vyazovskiy VV, Krone LB. Effects of clozapine-N-oxide and compound 21 on sleep in laboratory mice. eLife 2023; 12:e84740. [PMID: 36892930 PMCID: PMC9998087 DOI: 10.7554/elife.84740] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 01/03/2023] [Indexed: 03/10/2023] Open
Abstract
Designer receptors exclusively activated by designer drugs (DREADDs) are chemogenetic tools for remote control of targeted cell populations using chemical actuators that bind to modified receptors. Despite the popularity of DREADDs in neuroscience and sleep research, potential effects of the DREADD actuator clozapine-N-oxide (CNO) on sleep have never been systematically tested. Here, we show that intraperitoneal injections of commonly used CNO doses (1, 5, and 10 mg/kg) alter sleep in wild-type male laboratory mice. Using electroencephalography (EEG) and electromyography (EMG) to analyse sleep, we found a dose-dependent suppression of rapid eye movement (REM) sleep, changes in EEG spectral power during non-REM (NREM) sleep, and altered sleep architecture in a pattern previously reported for clozapine. Effects of CNO on sleep could arise from back-metabolism to clozapine or binding to endogenous neurotransmitter receptors. Interestingly, we found that the novel DREADD actuator, compound 21 (C21, 3 mg/kg), similarly modulates sleep despite a lack of back-metabolism to clozapine. Our results demonstrate that both CNO and C21 can modulate sleep of mice not expressing DREADD receptors. This implies that back-metabolism to clozapine is not the sole mechanism underlying side effects of chemogenetic actuators. Therefore, any chemogenetic experiment should include a DREADD-free control group injected with the same CNO, C21, or newly developed actuator. We suggest that electrophysiological sleep assessment could serve as a sensitive tool to test the biological inertness of novel chemogenetic actuators.
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Affiliation(s)
- Janine Traut
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of FreiburgFreiburgGermany
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of OxfordOxfordUnited Kingdom
| | - Jose Prius Mengual
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of OxfordOxfordUnited Kingdom
- The Kavli Institute for Nanoscience DiscoveryOxfordUnited Kingdom
| | - Elise J Meijer
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of OxfordOxfordUnited Kingdom
- The Kavli Institute for Nanoscience DiscoveryOxfordUnited Kingdom
| | - Laura E McKillop
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of OxfordOxfordUnited Kingdom
| | - Hannah Alfonsa
- Department of Pharmacology, University of OxfordOxfordUnited Kingdom
| | | | - Seo Ho Song
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical SchoolBostonUnited States
| | - Kristoffer D Fehér
- Geneva University Hospitals (HUG), Division of Psychiatric SpecialtiesGenevaSwitzerland
- University Hospital of Psychiatry and Psychotherapy, University of BernBernSwitzerland
| | - Dieter Riemann
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of FreiburgFreiburgGermany
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of OxfordOxfordUnited Kingdom
| | - Zoltan Molnar
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
| | - Colin J Akerman
- Department of Pharmacology, University of OxfordOxfordUnited Kingdom
| | - Vladyslav V Vyazovskiy
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of OxfordOxfordUnited Kingdom
- The Kavli Institute for Nanoscience DiscoveryOxfordUnited Kingdom
| | - Lukas B Krone
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of OxfordOxfordUnited Kingdom
- The Kavli Institute for Nanoscience DiscoveryOxfordUnited Kingdom
- University Hospital of Psychiatry and Psychotherapy, University of BernBernSwitzerland
- Centre for Experimental Neurology, University of BernBernSwitzerland
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He Z, Wang X, Ma K, Zheng L, Zhang Y, Liu C, Sun T, Wang P, Rong W, Niu J. Selective activation of the hypothalamic orexinergic but not melanin-concentrating hormone neurons following pilocarpine-induced seizures in rats. Front Neurosci 2022; 16:1056706. [DOI: 10.3389/fnins.2022.1056706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/11/2022] [Indexed: 12/05/2022] Open
Abstract
IntroductionSleep disorders are common comorbidities in patients with temporal lobe epilepsy (TLE), but the underlying mechanisms remain poorly understood. Since the lateral hypothalamic (LH) and the perifornical orexinergic (ORX) and melanin-concentrating hormone (MCH) neurons are known to play opposing roles in the regulation of sleep and arousal, dysregulation of ORX and MCH neurons might contribute to the disturbance of sleep-wakefulness following epileptic seizures.MethodsTo test this hypothesis, rats were treated with lithium chloride and pilocarpine to induce status epilepticus (SE). Electroencephalogram (EEG) and electromyograph (EMG) were recorded for analysis of sleep-wake states before and 24 h after SE. Double-labeling immunohistochemistry of c-Fos and ORX or MCH was performed on brain sections from the epileptic and control rats. In addition, anterograde and retrograde tracers in combination with c-Fos immunohistochemistry were used to analyze the possible activation of the amygdala to ORX neural pathways following seizures.ResultsIt was found that epileptic rats displayed prolonged wake phase and decreased non-rapid eye movement (NREM) and rapid eye movement (REM) phase compared to the control rats. Prominent neuronal activation was observed in the amygdala and the hypothalamus following seizures. Interestingly, in the LH and the perifornical nucleus, ORX but not MCH neurons were significantly activated (c-Fos+). Neural tracing showed that seizure-activated (c-Fos+) ORX neurons were closely contacted by axon terminals originating from neurons in the medial amygdala.DiscussionThese findings suggest that the spread of epileptic activity from amygdala to the hypothalamus causes selective activation of the wake-promoting ORX neurons but not sleep-promoting MCH neurons, which might contribute to the disturbance of sleep-wakefulness in TLE.
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Chen ZK, Dong H, Liu CW, Liu WY, Zhao YN, Xu W, Sun X, Xiong YY, Liu YY, Yuan XS, Wang B, Lazarus M, Chérasse Y, Li YD, Han F, Qu WM, Ding FF, Huang ZL. A cluster of mesopontine GABAergic neurons suppresses REM sleep and curbs cataplexy. Cell Discov 2022; 8:115. [PMID: 36280664 PMCID: PMC9592589 DOI: 10.1038/s41421-022-00456-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 08/02/2022] [Indexed: 11/17/2022] Open
Abstract
Physiological rapid eye movement (REM) sleep termination is vital for initiating non-REM (NREM) sleep or arousal, whereas the suppression of excessive REM sleep is promising in treating narcolepsy. However, the neuronal mechanisms controlling REM sleep termination and keeping sleep continuation remain largely unknown. Here, we reveal a key brainstem region of GABAergic neurons in the control of both physiological REM sleep and cataplexy. Using fiber photometry and optic tetrode recording, we characterized the dorsal part of the deep mesencephalic nucleus (dDpMe) GABAergic neurons as REM relatively inactive and two different firing patterns under spontaneous sleep–wake cycles. Next, we investigated the roles of dDpMe GABAergic neuronal circuits in brain state regulation using optogenetics, RNA interference technology, and celltype-specific lesion. Physiologically, dDpMe GABAergic neurons causally suppressed REM sleep and promoted NREM sleep through the sublaterodorsal nucleus and lateral hypothalamus. In-depth studies of neural circuits revealed that sublaterodorsal nucleus glutamatergic neurons were essential for REM sleep termination by dDpMe GABAergic neurons. In addition, dDpMe GABAergic neurons efficiently suppressed cataplexy in a rodent model. Our results demonstrated that dDpMe GABAergic neurons controlled REM sleep termination along with REM/NREM transitions and represented a novel potential target to treat narcolepsy.
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Affiliation(s)
- Ze-Ka Chen
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Hui Dong
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Cheng-Wei Liu
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Wen-Ying Liu
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Ya-Nan Zhao
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Wei Xu
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Xiao Sun
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yan-Yu Xiong
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yuan-Yuan Liu
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Xiang-Shan Yuan
- grid.8547.e0000 0001 0125 2443Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Bing Wang
- grid.8547.e0000 0001 0125 2443ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Michael Lazarus
- grid.20515.330000 0001 2369 4728International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki Japan
| | - Yoan Chérasse
- grid.20515.330000 0001 2369 4728International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki Japan
| | - Ya-Dong Li
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Fang Han
- grid.411634.50000 0004 0632 4559Sleep Medicine Center, Department of Respiratory and Critical Care Medicine, Peking University People’s Hospital, Beijing, China
| | - Wei-Min Qu
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Feng-Fei Ding
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Zhi-Li Huang
- grid.8547.e0000 0001 0125 2443Department of Pharmacology, School of Basic Medical Sciences; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
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Potter LE, Burgess CR. The melanin-concentrating hormone system as a target for the treatment of sleep disorders. Front Neurosci 2022; 16:952275. [PMID: 36177357 PMCID: PMC9513178 DOI: 10.3389/fnins.2022.952275] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
Given the widespread prevalence of sleep disorders and their impacts on health, it is critical that researchers continue to identify and evaluate novel avenues of treatment. Recently the melanin-concentrating hormone (MCH) system has attracted commercial and scientific interest as a potential target of pharmacotherapy for sleep disorders. This interest emerges from basic scientific research demonstrating a role for MCH in regulating sleep, and particularly REM sleep. In addition to this role in sleep regulation, the MCH system and the MCH receptor 1 (MCHR1) have been implicated in a wide variety of other physiological functions and behaviors, including feeding/metabolism, reward, anxiety, depression, and learning. The basic research literature on sleep and the MCH system, and the history of MCH drug development, provide cause for both skepticism and cautious optimism about the prospects of MCH-targeting drugs in sleep disorders. Extensive efforts have focused on developing MCHR1 antagonists for use in obesity, however, few of these drugs have advanced to clinical trials, and none have gained regulatory approval. Additional basic research will be needed to fully characterize the MCH system’s role in sleep regulation, for example, to fully differentiate between MCH-neuron and peptide/receptor-mediated functions. Additionally, a number of issues relating to drug design will continue to pose a practical challenge for novel pharmacotherapies targeting the MCH system.
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Affiliation(s)
- Liam E. Potter
- Department of Molecular and Integrative Physiology, Michigan Medicine, Ann Arbor, MI, United States
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Liam E. Potter,
| | - Christian R. Burgess
- Department of Molecular and Integrative Physiology, Michigan Medicine, Ann Arbor, MI, United States
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
- Christian R. Burgess,
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11
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He X, Li Y, Zhang N, Huang J, Ming X, Guo R, Hu Y, Ji P, Guo F. Melanin-concentrating hormone promotes anxiety and intestinal dysfunction via basolateral amygdala in mice. Front Pharmacol 2022; 13:906057. [PMID: 36016574 PMCID: PMC9395614 DOI: 10.3389/fphar.2022.906057] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 07/08/2022] [Indexed: 11/13/2022] Open
Abstract
The limbic system plays a pivotal role in stress-induced anxiety and intestinal disorders, but how the functional circuits between nuclei within the limbic system are engaged in the processing is still unclear. In our study, the results of fluorescence gold retrograde tracing and fluorescence immunohistochemistry showed that the melanin-concentrating hormone (MCH) neurons of the lateral hypothalamic area (LHA) projected to the basolateral amygdala (BLA). Both chemogenetic activation of MCH neurons and microinjection of MCH into the BLA induced anxiety disorder in mice, which were reversed by intra-BLA microinjection of MCH receptor 1 (MCHR1) blocker SNAP-94847. In the chronic acute combining stress (CACS) stimulated mice, SNAP94847 administrated in the BLA ameliorated anxiety-like behaviors and improved intestinal dysfunction via reducing intestinal permeability and inflammation. In conclusion, MCHergic circuit from the LHA to the BLA participates in the regulation of anxiety-like behavior in mice, and this neural pathway is related to the intestinal dysfunction in CACS mice by regulating intestinal permeability and inflammation.
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Affiliation(s)
- Xiaoman He
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Yuhang Li
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Nana Zhang
- Department of Clinical Laboratory, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jinfang Huang
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xing Ming
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Ruixiao Guo
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Yang Hu
- Qingdao Medical College, Qingdao University, Qingdao, China
| | - Pengfei Ji
- Qingdao Medical College, Qingdao University, Qingdao, China
| | - Feifei Guo
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, China
- *Correspondence: Feifei Guo,
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12
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Identification and New Indication of Melanin-Concentrating Hormone Receptor 1 (MCHR1) Antagonist Derived from Machine Learning and Transcriptome-Based Drug Repositioning Approaches. Int J Mol Sci 2022; 23:ijms23073807. [PMID: 35409167 PMCID: PMC8998904 DOI: 10.3390/ijms23073807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/28/2022] [Accepted: 03/28/2022] [Indexed: 01/02/2023] Open
Abstract
Melanin-concentrating hormone receptor 1 (MCHR1) has been a target for appetite suppressants, which are helpful in treating obesity. However, it is challenging to develop an MCHR1 antagonist because its binding site is similar to that of the human Ether-à-go-go-Related Gene (hERG) channel, whose inhibition may cause cardiotoxicity. Most drugs developed as MCHR1 antagonists have failed in clinical development due to cardiotoxicity caused by hERG inhibition. Machine learning-based prediction models can overcome these difficulties and provide new opportunities for drug discovery. In this study, we identified KRX-104130 with potent MCHR1 antagonistic activity and no cardiotoxicity through virtual screening using two MCHR1 binding affinity prediction models and an hERG-induced cardiotoxicity prediction model. In addition, we explored other possibilities for expanding the new indications for KRX-104130 using a transcriptome-based drug repositioning approach. KRX-104130 increased the expression of low-density lipoprotein receptor (LDLR), which induced cholesterol reduction in the gene expression analysis. This was confirmed by comparison with gene expression in a nonalcoholic steatohepatitis (NASH) patient group. In a NASH mouse model, the administration of KRX-104130 showed a protective effect by reducing hepatic lipid accumulation, liver injury, and histopathological changes, indicating a promising prospect for the therapeutic effect of NASH as a new indication for MCHR1 antagonists.
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13
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Yu X, Yan H, Li W. Recent advances in neuropeptide-related omics and gene editing: Spotlight on NPY and somatostatin and their roles in growth and food intake of fish. Front Endocrinol (Lausanne) 2022; 13:1023842. [PMID: 36267563 PMCID: PMC9576932 DOI: 10.3389/fendo.2022.1023842] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Feeding and growth are two closely related and important physiological processes in living organisms. Studies in mammals have provided us with a series of characterizations of neuropeptides and their receptors as well as their roles in appetite control and growth. The central nervous system, especially the hypothalamus, plays an important role in the regulation of appetite. Based on their role in the regulation of feeding, neuropeptides can be classified as orexigenic peptide and anorexigenic peptide. To date, the regulation mechanism of neuropeptide on feeding and growth has been explored mainly from mammalian models, however, as a lower and diverse vertebrate, little is known in fish regarding the knowledge of regulatory roles of neuropeptides and their receptors. In recent years, the development of omics and gene editing technology has accelerated the speed and depth of research on neuropeptides and their receptors. These powerful techniques and tools allow a more precise and comprehensive perspective to explore the functional mechanisms of neuropeptides. This paper reviews the recent advance of omics and gene editing technologies in neuropeptides and receptors and their progresses in the regulation of feeding and growth of fish. The purpose of this review is to contribute to a comparative understanding of the functional mechanisms of neuropeptides in non-mammalians, especially fish.
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14
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Alhassen W, Kobayashi Y, Su J, Robbins B, Nguyen H, Myint T, Yu M, Nauli SM, Saito Y, Alachkar A. Regulation of Brain Primary Cilia Length by MCH Signaling: Evidence from Pharmacological, Genetic, Optogenetic, and Chemogenic Manipulations. Mol Neurobiol 2021; 59:245-265. [PMID: 34665407 DOI: 10.1007/s12035-021-02511-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/29/2021] [Indexed: 12/23/2022]
Abstract
The melanin-concentrating hormone (MCH) system is involved in numerous functions, including energy homeostasis, food intake, sleep, stress, mood, aggression, reward, maternal behavior, social behavior, and cognition. In rodents, MCH acts on MCHR1, a G protein-coupled receptor, which is widely expressed in the brain and abundantly localized to neuronal primary cilia. Cilia act as cells' antennas and play crucial roles in cell signaling to detect and transduce external stimuli to regulate cell differentiation and migration. Cilia are highly dynamic in terms of their length and morphology; however, it is not known if cilia length is causally regulated by MCH system activation in vivo. In the current work, we examined the effects of activation and inactivation of MCH system on cilia lengths by using different experimental models and methodologies, including organotypic brain slice cultures from rat prefrontal cortex (PFC) and caudate-putamen (CPu), in vivo pharmacological (MCHR1 agonist and antagonist GW803430), germline and conditional genetic deletion of MCHR1 and MCH, optogenetic, and chemogenetic (designer receptors exclusively activated by designer drugs (DREADD)) approaches. We found that stimulation of MCH system either directly through MCHR1 activation or indirectly through optogenetic and chemogenetic-mediated excitation of MCH-neuron, caused cilia shortening, detected by the quantification of the presence of ADCY3 protein, a known primary cilia marker. In contrast, inactivation of MCH signaling through pharmacological MCHR1 blockade or through genetic manipulations - germline deletion of MCHR1 and conditional ablation of MCH neurons - induced cilia lengthening. Our study is the first to uncover the causal effects of the MCH system in the regulation of the length of brain neuronal primary cilia. These findings place MCH system at a unique position in the ciliary signaling in physiological and pathological conditions and implicate MCHR1 present at primary cilia as a potential therapeutic target for the treatment of pathological conditions characterized by impaired primary cilia function associated with the modification of its length.
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Affiliation(s)
- Wedad Alhassen
- Departments of Pharmaceutical Sciences, School of Pharmacy, University of California, Irvine, CA, 92697, USA
| | - Yuki Kobayashi
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8521, Japan
| | - Jessica Su
- Departments of Pharmaceutical Sciences, School of Pharmacy, University of California, Irvine, CA, 92697, USA
| | - Brianna Robbins
- Departments of Pharmaceutical Sciences, School of Pharmacy, University of California, Irvine, CA, 92697, USA
| | - Henry Nguyen
- Departments of Pharmaceutical Sciences, School of Pharmacy, University of California, Irvine, CA, 92697, USA
| | - Thant Myint
- Departments of Pharmaceutical Sciences, School of Pharmacy, University of California, Irvine, CA, 92697, USA
| | - Micah Yu
- Departments of Pharmaceutical Sciences, School of Pharmacy, University of California, Irvine, CA, 92697, USA
| | - Surya M Nauli
- Department of Biomedical and Pharmaceutical Sciences, School of Pharmacy, Chapman University, Health Science Campus, Chapman University, Irvine, CA, 92618, USA
| | - Yumiko Saito
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8521, Japan
| | - Amal Alachkar
- Departments of Pharmaceutical Sciences, School of Pharmacy, University of California, Irvine, CA, 92697, USA. .,Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California, Irvine, CA, 92697, USA.
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15
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Seifinejad A, Vassalli A, Tafti M. Neurobiology of cataplexy. Sleep Med Rev 2021; 60:101546. [PMID: 34607185 DOI: 10.1016/j.smrv.2021.101546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 07/29/2021] [Accepted: 09/06/2021] [Indexed: 11/17/2022]
Abstract
Cataplexy is the pathognomonic and the most striking symptom of narcolepsy. It has originally been, and still is now, widely considered as an abnormal manifestation of rapid eye movement (REM) sleep during wakefulness due to the typical muscle atonia. The neurocircuits of cataplexy, originally confined to the brainstem as those of REM sleep atonia, now include the hypothalamus, dorsal raphe (DR), amygdala and frontal cortex, and its neurochemistry originally focused on catecholamines and acetylcholine now extend to hypocretin (HCRT) and other neuromodulators. Here, we review the neuroanatomy and neurochemistry of cataplexy and propose that cataplexy is a distinct brain state that, despite similarities with REM sleep, involves cataplexy-specific features.
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Affiliation(s)
- Ali Seifinejad
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1005 Lausanne, Switzerland
| | - Anne Vassalli
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1005 Lausanne, Switzerland
| | - Mehdi Tafti
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1005 Lausanne, Switzerland.
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16
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Adamantidis AR, Schmidt MH, Carter ME, Burdakov D, Peyron C, Scammell TE. A circuit perspective on narcolepsy. Sleep 2021; 43:5699663. [PMID: 31919524 PMCID: PMC7215265 DOI: 10.1093/sleep/zsz296] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/13/2019] [Indexed: 01/25/2023] Open
Abstract
The sleep disorder narcolepsy is associated with symptoms related to either boundary state control that include excessive daytime sleepiness and sleep fragmentation, or rapid eye movement (REM) sleep features including cataplexy, sleep paralysis, hallucinations, and sleep-onset REM sleep events (SOREMs). Although the loss of Hypocretin/Orexin (Hcrt/Ox) peptides or their receptors have been associated with the disease, here we propose a circuit perspective of the pathophysiological mechanisms of these narcolepsy symptoms that encompasses brain regions, neuronal circuits, cell types, and transmitters beyond the Hcrt/Ox system. We further discuss future experimental strategies to investigate brain-wide mechanisms of narcolepsy that will be essential for a better understanding and treatment of the disease.
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Affiliation(s)
- A R Adamantidis
- Department of Neurology, Centre for Experimental Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.,Department of Biomedical Research, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
| | - M H Schmidt
- Department of Neurology, Centre for Experimental Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.,Ohio Sleep Medicine Institute, Dublin, OH
| | - M E Carter
- Department of Biology, Program in Neuroscience, Williams College, Williamstown, MA
| | - D Burdakov
- Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - C Peyron
- Center for Research in Neuroscience of Lyon, SLEEP team, CNRS UMR5292, INSERM U1028, University Lyon 1, Bron, France
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
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17
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MCH-R1 Antagonist GPS18169, a Pseudopeptide, Is a Peripheral Anti-Obesity Agent in Mice. Molecules 2021; 26:molecules26051291. [PMID: 33673598 PMCID: PMC7957705 DOI: 10.3390/molecules26051291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/17/2021] [Accepted: 02/22/2021] [Indexed: 01/01/2023] Open
Abstract
Melanin-concentrating hormone (MCH) is a 19 amino acid long peptide found in the brain of animals, including fishes, batrachians, and mammals. MCH is implicated in appetite and/or energy homeostasis. Antagonists at its receptor (MCH-R1) could be major tools (or ultimately drugs) to understand the mechanism of MCH action and to fight the obesity syndrome that is a worldwide societal health problem. Ever since the deorphanisation of the MCH receptor, we cloned, expressed, and characterized the receptor MCH-R1 and started a vast medicinal chemistry program aiming at the discovery of such usable compounds. In the present final work, we describe GPS18169, a pseudopeptide antagonist at the MCH-R1 receptor with an affinity in the nanomolar range and a Ki for its antagonistic effect in the 20 picomolar range. Its metabolic stability is rather ameliorated compared to its initial parent compound, the antagonist S38151. We tested it in an in vivo experiment using high diet mice. GPS18169 was found to be active in limiting the accumulation of adipose tissues and, correlatively, we observed a normalization of the insulin level in the treated animals, while no change in food or water consumption was observed.
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18
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Cataldi M, Arnaldi D, Tucci V, De Carli F, Patti G, Napoli F, Pace M, Maghnie M, Nobili L. Sleep disorders in Prader-Willi syndrome, evidence from animal models and humans. Sleep Med Rev 2021; 57:101432. [PMID: 33567377 DOI: 10.1016/j.smrv.2021.101432] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 02/06/2023]
Abstract
Prader-Willi Syndrome (PWS) is a complex genetic disorder with multiple cognitive, behavioral and endocrine dysfunctions. Sleep alterations and sleep disorders such as Sleep-disordered breathing and Central disorders of hypersomnolence are frequently recognized (either isolated or in comorbidity). The aim of the review is to highlight the pathophysiology and the clinical features of sleep disorders in PWS, providing the basis for early diagnosis and management. We reviewed the genetic features of the syndrome and the possible relationship with sleep alterations in animal models, and we described sleep phenotypes, diagnostic tools and therapeutic approaches in humans. Moreover, we performed a meta-analysis of cerebrospinal fluid orexin levels in patients with PWS; significantly lower levels of orexin were detected in PWS with respect to control subjects (although significantly higher than the ones of narcoleptic patients). Sleep disorders in humans with PWS are multifaceted and are often the result of different mechanisms. Since hypothalamic dysfunction seems to partially influence metabolic, respiratory and sleep/wake characteristics of this syndrome, additional studies are required in this framework.
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Affiliation(s)
- Matteo Cataldi
- Unit of Child Neuropsychiatry, Department of Medical and Surgical Neuroscience and Rehabilitation, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Dario Arnaldi
- IRCCS Ospedale Policlinico San Martino, Genoa, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy
| | - Valter Tucci
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Fabrizio De Carli
- Institute of Bioimaging and Molecular Physiology, National Research Council, Genoa, Italy
| | - Giuseppa Patti
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy; Department of Pediatrics, Istituto Giannina Gaslini, University of Genoa, Genoa, Italy
| | - Flavia Napoli
- Department of Pediatrics, Istituto Giannina Gaslini, University of Genoa, Genoa, Italy
| | - Marta Pace
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Mohamad Maghnie
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy; Department of Pediatrics, Istituto Giannina Gaslini, University of Genoa, Genoa, Italy
| | - Lino Nobili
- Unit of Child Neuropsychiatry, Department of Medical and Surgical Neuroscience and Rehabilitation, IRCCS Istituto Giannina Gaslini, Genoa, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy.
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19
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Berteotti C, Liguori C, Pace M. Dysregulation of the orexin/hypocretin system is not limited to narcolepsy but has far-reaching implications for neurological disorders. Eur J Neurosci 2020; 53:1136-1154. [PMID: 33290595 DOI: 10.1111/ejn.15077] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 12/23/2022]
Abstract
Neuropeptides orexin A and B (OX-A/B, also called hypocretin 1 and 2) are released selectively by a population of neurons which projects widely into the entire central nervous system but is localized in a restricted area of the tuberal region of the hypothalamus, caudal to the paraventricular nucleus. The OX system prominently targets brain structures involved in the regulation of wake-sleep state switching, and also orchestrates multiple physiological functions. The degeneration and dysregulation of the OX system promotes narcoleptic phenotypes both in humans and animals. Hence, this review begins with the already proven involvement of OX in narcolepsy, but it mainly discusses the new pre-clinical and clinical insights of the role of OX in three major neurological disorders characterized by sleep impairment which have been recently associated with OX dysfunction, such as Alzheimer's disease, stroke and Prader Willi syndrome, and have been emerged over the past 10 years to be strongly associated with the OX dysfunction and should be more considered in the future. In the light of the impairment of the OX system in these neurological disorders, it is conceivable to speculate that the integrity of the OX system is necessary for a healthy functioning body.
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Affiliation(s)
- Chiara Berteotti
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Claudio Liguori
- Sleep Medicine Centre, Neurology Unit, University Hospital Tor Vergata, Rome, Italy.,Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Marta Pace
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, Genova, Italy
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20
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Bandaru SS, Khanday MA, Ibrahim N, Naganuma F, Vetrivelan R. Sleep-Wake Control by Melanin-Concentrating Hormone (MCH) Neurons: a Review of Recent Findings. Curr Neurol Neurosci Rep 2020; 20:55. [PMID: 33006677 DOI: 10.1007/s11910-020-01075-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE OF THE REVIEW Melanin-concentrating hormone (MCH)-expressing neurons located in the lateral hypothalamus are considered as an integral component of sleep-wake circuitry. However, the precise role of MCH neurons in sleep-wake regulation has remained unclear, despite several years of research employing a wide range of techniques. We review recent data on this aspect, which are mostly inconsistent, and propose a novel role for MCH neurons in sleep regulation. RECENT FINDINGS While almost all studies using "gain-of-function" approaches show an increase in rapid eye movement sleep (or paradoxical sleep; PS), loss-of-function approaches have not shown reductions in PS. Similarly, the reported changes in wakefulness or non-rapid eye movement sleep (slow-wave sleep; SWS) with manipulation of the MCH system using conditional genetic methods are inconsistent. Currently available data do not support a role for MCH neurons in spontaneous sleep-wake but imply a crucial role for them in orchestrating sleep-wake responses to changes in external and internal environments.
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Affiliation(s)
- Sathyajit S Bandaru
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA
| | - Mudasir A Khanday
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Nazifa Ibrahim
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA.,Department of Public Health Sciences, University of Massachusetts, Amherst, MA, USA
| | - Fumito Naganuma
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA.,Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Ramalingam Vetrivelan
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA. .,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA.
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21
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Pace M, Falappa M, Freschi A, Balzani E, Berteotti C, Lo Martire V, Kaveh F, Hovig E, Zoccoli G, Amici R, Cerri M, Urbanucci A, Tucci V. Loss of Snord116 impacts lateral hypothalamus, sleep, and food-related behaviors. JCI Insight 2020; 5:137495. [PMID: 32365348 DOI: 10.1172/jci.insight.137495] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/24/2020] [Indexed: 12/14/2022] Open
Abstract
Imprinted genes are highly expressed in the hypothalamus; however, whether specific imprinted genes affect hypothalamic neuromodulators and their functions is unknown. It has been suggested that Prader-Willi syndrome (PWS), a neurodevelopmental disorder caused by lack of paternal expression at chromosome 15q11-q13, is characterized by hypothalamic insufficiency. Here, we investigate the role of the paternally expressed Snord116 gene within the context of sleep and metabolic abnormalities of PWS, and we report a significant role of this imprinted gene in the function and organization of the 2 main neuromodulatory systems of the lateral hypothalamus (LH) - namely, the orexin (OX) and melanin concentrating hormone (MCH) - systems. We observed that the dynamics between neuronal discharge in the LH and the sleep-wake states of mice with paternal deletion of Snord116 (PWScrm+/p-) are compromised. This abnormal state-dependent neuronal activity is paralleled by a significant reduction in OX neurons in the LH of mutant mice. Therefore, we propose that an imbalance between OX- and MCH-expressing neurons in the LH of mutant mice reflects a series of deficits manifested in the PWS, such as dysregulation of rapid eye movement (REM) sleep, food intake, and temperature control.
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Affiliation(s)
- Marta Pace
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, via Morego 30, Italy
| | - Matteo Falappa
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, via Morego 30, Italy.,Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università degli Studi di Genova, Genova, Italy
| | - Andrea Freschi
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, via Morego 30, Italy
| | - Edoardo Balzani
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, via Morego 30, Italy
| | - Chiara Berteotti
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Viviana Lo Martire
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Fatemeh Kaveh
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Eivind Hovig
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.,Centre for Bioinformatics, Department of Informatics, University of Oslo, Oslo, Norway
| | - Giovanna Zoccoli
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Roberto Amici
- Department of Biomedical and NeuroMotor Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Matteo Cerri
- Department of Biomedical and NeuroMotor Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Alfonso Urbanucci
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Valter Tucci
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, via Morego 30, Italy
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22
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Mahoney CE, Mochizuki T, Scammell TE. Dual orexin receptor antagonists increase sleep and cataplexy in wild type mice. Sleep 2020; 43:zsz302. [PMID: 31830270 PMCID: PMC7294412 DOI: 10.1093/sleep/zsz302] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/26/2019] [Indexed: 11/13/2022] Open
Abstract
Orexin receptor antagonists are clinically useful for treating insomnia, but thorough blockade of orexin signaling could cause narcolepsy-like symptoms. Specifically, while sleepiness is a desirable effect, an orexin antagonist could also produce cataplexy, sudden episodes of muscle weakness often triggered by strong, positive emotions. In this study, we examined the effects of dual orexin receptor antagonists (DORAs), lemborexant (E2006) and almorexant, on sleep-wake behavior and cataplexy during the dark period in wild-type (WT) mice and prepro-orexin knockout (OXKO) mice. In WT mice, lemborexant at 10 and 30 mg/kg quickly induced NREM sleep in a dose-dependent fashion. In contrast, lemborexant did not alter sleep-wake behavior in OXKO mice. Under the baseline condition, cataplexy was rare in lemborexant-treated WT mice, but when mice were given chocolate as a rewarding stimulus, lemborexant dose-dependently increased cataplexy. Almorexant produced similar results. Collectively, these results demonstrate that DORAs potently increase NREM and REM sleep in mice via blockade of orexin signaling, and higher doses can cause cataplexy when co-administered with a likely rewarding stimulus.
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Affiliation(s)
- Carrie E Mahoney
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Takatoshi Mochizuki
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Japan
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
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23
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Sun Y, Liu M. Hypothalamic MCH Neuron Activity Dynamics during Cataplexy of Narcolepsy. eNeuro 2020; 7:ENEURO.0017-20.2020. [PMID: 32303567 PMCID: PMC7196720 DOI: 10.1523/eneuro.0017-20.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/03/2020] [Accepted: 03/07/2020] [Indexed: 12/21/2022] Open
Abstract
Hypothalamic orexin (hypocretin, HCRT) deficiency causes sleep disorder narcolepsy with cataplexy in humans and murine. As another integral group of sleep/wake-regulating neurons in the same brain area, the melanin-concentrating hormone (MCH) neurons' involvement in cataplexy remains ambiguous. Here we used the live animal deep-brain calcium (Ca2+) imaging tool to record MCH neuron dynamics during cataplexy by expressing calcium sensor GCaMP6s into genetically defined MCH neurons in orexin knock-out mice, which are a model of human narcolepsy. Similar to wild-type mice, MCH neurons of the narcoleptic mice displayed significantly higher Ca2+ transient fluorescent intensity during rapid eye movement (REM) sleep and active waking (AW) episodes compared with non-REM (NREM) sleep. Moreover, MCH neurons displayed significantly lower Ca2+ signals during cataplexy. Importantly, a pre-cataplexy elevation of Ca2+ signals from MCH neurons was not a prerequisite for cataplexy initiation. Our results demonstrated the inactivation status of MCH neurons during cataplexy and suggested that MCH neurons are not involved in the initiation and maintenance of cataplexy in orexin knock-out mice.
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Affiliation(s)
- Ying Sun
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425
| | - Meng Liu
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425
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24
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Hung CJ, Ono D, Kilduff TS, Yamanaka A. Dual orexin and MCH neuron-ablated mice display severe sleep attacks and cataplexy. eLife 2020; 9:54275. [PMID: 32314734 PMCID: PMC7173968 DOI: 10.7554/elife.54275] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 04/03/2020] [Indexed: 12/25/2022] Open
Abstract
Orexin/hypocretin-producing and melanin-concentrating hormone-producing (MCH) neurons are co-extensive in the hypothalamus and project throughout the brain to regulate sleep/wakefulness. Ablation of orexin neurons decreases wakefulness and results in a narcolepsy-like phenotype, whereas ablation of MCH neurons increases wakefulness. Since it is unclear how orexin and MCH neurons interact to regulate sleep/wakefulness, we generated transgenic mice in which both orexin and MCH neurons could be ablated. Double-ablated mice exhibited increased wakefulness and decreased both rapid eye movement (REM) and non-REM (NREM) sleep. Double-ablated mice showed severe cataplexy compared with orexin neuron-ablated mice, suggesting that MCH neurons normally suppress cataplexy. Double-ablated mice also showed frequent sleep attacks with elevated spectral power in the delta and theta range, a unique state that we call 'delta-theta sleep'. Together, these results indicate a functional interaction between orexin and MCH neurons in vivo that suggests the synergistic involvement of these neuronal populations in the sleep/wakefulness cycle.
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Affiliation(s)
- Chi Jung Hung
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Daisuke Ono
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Thomas S Kilduff
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, United States
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
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25
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Romigi A, Bari M, Liguori C, Izzi F, Rapino C, Nuccetelli M, Battista N, Bernardini S, Centonze D, Mercuri NB, Placidi F, Maccarrone M. CSF Levels of the Endocannabinoid Anandamide are Reduced in Patients with Untreated Narcolepsy Type 1: A Pilot Study. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 19:142-147. [PMID: 32148204 DOI: 10.2174/1871527319666200309115602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/13/2020] [Accepted: 01/21/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Endocannabinoids (ECs) modulate both excitatory and inhibitory components in the CNS. There is a growing body of evidence that shows ECs influence both hypothalamic orexinergic and histaminergic neurons involved in narcolepsy physiopathology. Therefore, ECs may influence sleep and sleep-wake cycle. OBJECTIVE To evaluate EC levels in the CSF of untreated narcoleptic patients to test whether ECs are dysregulated in Narcolepsy Type 1 (NT1) and Type 2 (NT2). METHODS We compared CSF Anandamide (AEA), 2-Arachidonoylglycerol (2-AG) and orexin in narcoleptic drug-naïve patients and in a sample of healthy subjects. RESULTS We compared NT1 (n=6), NT2 (n=6), and healthy controls (n=6). We found significantly reduced AEA levels in NT1 patients compared to both NT2 and controls. No differences were found between AEA levels in NT2 versus controls and between 2-AG levels in all groups, although a trend toward a decrease in NT1 was evident. Finally, the CSF AEA level was related to CSF orexin levels in all subjects. CONCLUSION We demonstrated that the EC system is dysregulated in NT1.
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Affiliation(s)
- Andrea Romigi
- IRCCS Neuromed Sleep Medicine Center, Via Atinense, 18 Pozzilli (IS), Italy
| | - Monica Bari
- Department of Experimental Medicine, University of Rome 'Tor Vergata', Rome, Italy
| | - Claudio Liguori
- Department of Systems Medicine, University of Rome 'Tor Vergata', Rome, Italy
| | - Francesca Izzi
- Department of Systems Medicine, University of Rome 'Tor Vergata', Rome, Italy
| | - Cinzia Rapino
- Faculty of Bioscience and Technology for Food, University of Teramo, Agriculture and Environment, Teramo, Italy
| | - Marzia Nuccetelli
- Department of Experimental Medicine, University of Rome 'Tor Vergata', Rome, Italy
| | - Natalia Battista
- Faculty of Bioscience and Technology for Food, University of Teramo, Agriculture and Environment, Teramo, Italy
| | - Sergio Bernardini
- Department of Experimental Medicine, University of Rome 'Tor Vergata', Rome, Italy
| | - Diego Centonze
- IRCCS Neuromed Sleep Medicine Center, Via Atinense, 18 Pozzilli (IS), Italy
| | | | - Fabio Placidi
- Department of Systems Medicine, University of Rome 'Tor Vergata', Rome, Italy
| | - Mauro Maccarrone
- Campus Bio-Medico University of Rome, Italy.,European Center for Brain Research, IRCCS Santa Lucia Foundation, Rome, Italy
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26
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REM sleep behavior disorder in narcolepsy: A secondary form or an intrinsic feature? Sleep Med Rev 2019; 50:101254. [PMID: 31931470 DOI: 10.1016/j.smrv.2019.101254] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 12/09/2019] [Accepted: 12/09/2019] [Indexed: 01/17/2023]
Abstract
Disrupted nighttime sleep is one of the pentad of symptoms defining Narcolepsy. REM sleep behavior disorder (RBD) largely contributes to night sleep disruption and narcolepsy is the most common cause of secondary RBD. However, RBD linked to narcolepsy (N-RBD) has been insufficiently characterized, leaving unsolved a number of issues. Indeed, it is still debated whether N-RBD is an intrinsic feature of narcolepsy, as indubitable for cataplexy, and therefore strictly linked to the cerebrospinal fluid hypocretin-1 (CSF hcrt-1) deficiency, or an associated feature, with a still unclear pathophysiology. The current review aims at rendering a comprehensive state-of-the-art of N-RBD, highlighting the open and unsettled topics. RBD reportedly affects 30-60% of patients with Narcolepsy type 1 (NT1), but it may be seen also in Narcolepsy type 2 (NT2). When compared to idiopathic/isolated RBD (iRBD), N-RBD has been reported to be characterized by less energetic and quieter episode, which however occur with the same probability in the first and the second part of the night and sometime even subcontinuously. N-RBD patients are generally younger than those with iRBD. N-RBD has been putatively linked to wake-sleep instability due to CSF hcrt-1 deficiency, but this latter by itself cannot explain completely the phenomenon as N-RBD has not been universally linked to low CSF hcrt-1 levels and it may be observed also in NT2. Therefore, other factors may probably play a role and further studies are needed to clarify this issue. In addition, therapeutic options have been poorly investigated.
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27
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The role of co-neurotransmitters in sleep and wake regulation. Mol Psychiatry 2019; 24:1284-1295. [PMID: 30377299 PMCID: PMC6491268 DOI: 10.1038/s41380-018-0291-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 09/17/2018] [Accepted: 10/08/2018] [Indexed: 12/11/2022]
Abstract
Sleep and wakefulness control in the mammalian brain requires the coordination of various discrete interconnected neurons. According to the most conventional sleep model, wake-promoting neurons (WPNs) and sleep-promoting neurons (SPNs) compete for network dominance, creating a systematic "switch" that results in either the sleep or awake state. WPNs and SPNs are ubiquitous in the brainstem and diencephalon, areas that together contain <1% of the neurons in the human brain. Interestingly, many of these WPNs and SPNs co-express and co-release various types of the neurotransmitters that often have opposing modulatory effects on the network. Co-transmission is often beneficial to structures with limited numbers of neurons because it provides increasing computational capability and flexibility. Moreover, co-transmission allows subcortical structures to bi-directionally control postsynaptic neurons, thus helping to orchestrate several complex physiological functions such as sleep. Here, we present an in-depth review of co-transmission in hypothalamic WPNs and SPNs and discuss its functional significance in the sleep-wake network.
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28
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Kroeger D, Bandaru SS, Madara JC, Vetrivelan R. Ventrolateral periaqueductal gray mediates rapid eye movement sleep regulation by melanin-concentrating hormone neurons. Neuroscience 2019; 406:314-324. [PMID: 30890480 DOI: 10.1016/j.neuroscience.2019.03.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 02/20/2019] [Accepted: 03/08/2019] [Indexed: 11/28/2022]
Abstract
Neurons containing melanin-concentrating hormone (MCH) in the lateral hypothalamic area (LH) have been shown to promote rapid eye movement sleep (REMs) in mice. However, the downstream neural pathways through which MCH neurons influence REMs remained unclear. Because MCH neurons are considered to be primarily inhibitory, we hypothesized that these neurons inhibit the midbrain 'REMs-suppressing' region consisting of the ventrolateral periaqueductal gray and the lateral pontine tegmentum (vlPAG/LPT) to promote REMs. To test this hypothesis, we optogenetically inhibited MCH terminals in the vlPAG/LPT under baseline conditions as well as with simultaneous chemogenetic activation of MCH soma. We found that inhibition of MCH terminals in the vlPAG/LPT significantly reduced transitions into REMs during spontaneous sleep-wake cycles and prevented the increase in REMs transitions observed after chemogenetic activation of MCH neurons. These results strongly suggest that the vlPAG/LPT may be an essential relay through which MCH neurons modulate REMs.
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Affiliation(s)
- Daniel Kroeger
- Department of Neurology, Program in Neuroscience and Division of Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA-02215, United States.
| | - Sathyajit S Bandaru
- Department of Neurology, Program in Neuroscience and Division of Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA-02215, United States.
| | - Joseph C Madara
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA-02215, United States.
| | - Ramalingam Vetrivelan
- Department of Neurology, Program in Neuroscience and Division of Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA-02215, United States.
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