1
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Dale NC, Hoyer D, Jacobson LH, Pfleger KDG, Johnstone EKM. Orexin Signaling: A Complex, Multifaceted Process. Front Cell Neurosci 2022; 16:812359. [PMID: 35496914 PMCID: PMC9044999 DOI: 10.3389/fncel.2022.812359] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/07/2022] [Indexed: 11/15/2022] Open
Abstract
The orexin system comprises two G protein-coupled receptors, OX1 and OX2 receptors (OX1R and OX2R, respectively), along with two endogenous agonists cleaved from a common precursor (prepro-orexin), orexin-A (OX-A) and orexin-B (OX-B). For the receptors, a complex array of signaling behaviors has been reported. In particular, it becomes obvious that orexin receptor coupling is very diverse and can be tissue-, cell- and context-dependent. Here, the early signal transduction interactions of the orexin receptors will be discussed in depth, with particular emphasis on the direct G protein interactions of each receptor. In doing so, it is evident that ligands, additional receptor-protein interactions and cellular environment all play important roles in the G protein coupling profiles of the orexin receptors. This has potential implications for our understanding of the orexin system’s function in vivo in both central and peripheral environments, as well as the development of novel agonists, antagonists and possibly allosteric modulators targeting the orexin system.
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Affiliation(s)
- Natasha C. Dale
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Daniel Hoyer
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - Laura H. Jacobson
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- Dimerix Limited, Nedlands, WA, Australia
- *Correspondence: Kevin D. G. Pfleger,
| | - Elizabeth K. M. Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
- Elizabeth K. M. Johnstone,
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2
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Sleep Disorders in dogs: A Pathophysiological and Clinical Review. Top Companion Anim Med 2021; 43:100516. [PMID: 33556640 DOI: 10.1016/j.tcam.2021.100516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 01/22/2021] [Accepted: 01/29/2021] [Indexed: 12/11/2022]
Abstract
Sleep is a fundamental process in mammals, including domestic dogs. Disturbances in sleep affect physiological functions like cognitive and physical performance, immune response, pain sensation and increase the risk of diseases. In dogs, sleep can be affected by several conditions, with narcolepsy, REM sleep behavior disorder and sleep breathing disorders being the most frequent causes. Furthermore, sleep disturbances can be a symptom of other primary diseases where they can contribute to the worsening of clinical signs. This review describes reciprocally interacting sleep and wakefulness promoting systems and how their dysfunction can explain the pathophysiological mechanisms of sleep disorders. Additionally, this work discusses the clinical characteristics, diagnostic tools and available treatments for these disorders while highlighting areas in where further studies are needed so as to improve their treatment and prevention.
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3
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Nagai T, Sunami Y, Kato R, Sugai M, Takahara M, Ohta K, Fujinaka H, Goto K, Okanura O, Nakajima T, Ozawa T. Coexistence of Hereditary Spastic Paraplegia Type 4 and Narcolepsy: A Case Report. Case Rep Neurol 2021; 13:84-91. [PMID: 33708099 PMCID: PMC7923727 DOI: 10.1159/000512404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 10/10/2020] [Indexed: 11/19/2022] Open
Abstract
Spastic paraplegia type 4 (SPG4) is the most common type of hereditary spastic paraplegia (HSP) caused by the mutations in the SPAST gene, which encodes a microtubule-severing protein named spastin. Spastin regulates the number and mobility of microtubules and is essential for axonal outgrowth and neuronal morphogenesis. Herein, we report a patient with SPG4 harboring a novel donor splice site mutation in the SPAST gene (c.1616+1dupG). Although SPG4 usually manifests itself as a pure form of HSP, this patient exhibited a slow progressive cognitive decline and also developed narcolepsy type 2 (narcolepsy without cataplexy) prior to the onset of SPG4. Recently, cognitive decline has attracted attention as a main non-motor symptom of SPG4. However, this is the first reported case of a patient developing both SPG4 and narcolepsy, although it remains unclear whether the manifestation of the two diseases is a coincidence or an association. In this report, we describe the clinical symptoms and genetic background of the patient.
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Affiliation(s)
- Takahiro Nagai
- Department of Neurology, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
- Department of Neurology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Yoko Sunami
- Department of Neurology, Tokyo Metropolitan Neurological Hospital, Fuchu, Japan
| | - Risa Kato
- Department of Clinical Laboratory, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
| | - Megumi Sugai
- Department of Clinical Laboratory, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
| | - Makoto Takahara
- Department of Internal Medicine, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
| | - Kentaro Ohta
- Department of Neurology, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
| | - Hidehiko Fujinaka
- Department of Pediatrics, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
- Department of Clinical Research, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
| | - Kiyoe Goto
- Department of Genetic Counseling, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
| | - Osamu Okanura
- Department of Clinical Laboratory, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
| | - Takashi Nakajima
- Department of Neurology, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
| | - Tetsuo Ozawa
- Department of Internal Medicine, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
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Abstract
Twenty-two years after their discovery, the hypocretins (Hcrts), also known as orexins, are two of the most studied peptidergic systems, involved in myriad physiological systems that range from sleep, arousal, motivation, homeostatic regulation, fear, anxiety and learning. A causal relationship between activity of Hcrt and arousal stability was established shortly after their discovery and have led to the development of a new class of drugs to treat insomnia. In this review we discuss the many faces of the Hcrt system and examine recent findings that implicate decreased Hcrt function in the pathogenesis of a number of neuropsychiatric conditions. We also discuss future therapeutic strategies to replace or enhance Hcrt function as a treatment option for these neuropsychiatric conditions.
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Affiliation(s)
- Erica Seigneur
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
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5
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Mavaro I, De Felice E, Palladino A, D'Angelo L, de Girolamo P, Attanasio C. Anatomical templates for tissue (re)generation and beyond. Biotechnol Bioeng 2020; 117:3938-3951. [PMID: 32776516 DOI: 10.1002/bit.27533] [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: 05/26/2020] [Revised: 07/27/2020] [Accepted: 08/07/2020] [Indexed: 11/12/2022]
Abstract
Induced pluripotent stem cells (iPSCs) represent a valuable alternative to stem cells in regenerative medicine overcoming their ethical limitations, like embryo disruption. Takahashi and Yamanaka in 2006 reprogrammed, for the first time, mouse fibroblasts into iPSCs through the retroviral delivery of four reprogramming factors: Oct3/4, Sox2, c-Myc, and Klf4. Since then, several studies started reporting the derivation of iPSC lines from animals other than rodents for translational and veterinary medicine. Here, we review the potential of using these cells for further intriguing applications, such as "cellular agriculture." iPSCs, indeed, can be a source of in vitro, skeletal muscle tissue, namely "cultured meat," a product that improves animal welfare and encourages the consumption of healthier meat along with environmental preservation. Also, we report the potential of using iPSCs, obtained from endangered species, for therapeutic treatments for captive animals and for assisted reproductive technologies as well. This review offers a unique opportunity to explore the whole spectrum of iPSC applications from regenerative translational and veterinary medicine to the production of artificial meat and the preservation of currently endangered species.
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Affiliation(s)
- Isabella Mavaro
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy.,Interdepartmental Center for Research in Biomaterials (CRIB), University of Naples Federico II, Naples, Italy
| | - Elena De Felice
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Antonio Palladino
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy
| | - Livia D'Angelo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy.,Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Paolo de Girolamo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy
| | - Chiara Attanasio
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy.,Interdepartmental Center for Research in Biomaterials (CRIB), University of Naples Federico II, Naples, Italy.,Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia, Naples, Italy
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6
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Mari L, Shea A. Symptomatic Narcolepsy/Cataplexy in a Dog with Brainstem Meningoencephalitis of Unknown Origin. J Am Anim Hosp Assoc 2020; 56:e56201. [PMID: 31961221 DOI: 10.5326/jaaha-ms-6892] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A 4 yr old, intact female cocker spaniel was presented for investigation of acute, progressive lethargy/hypersomnia; vestibular signs; and cataplexy. A narcolepsy-cataplexy episode with associated hypertension and bradycardia was triggered during examination. There was no evidence of arrhythmia on electrocardiography during the episode. Hematology, serum biochemistry, and thoracic and abdominal imaging were unremarkable. MRI of the brain and cerebrospinal fluid analysis were compatible with meningoencephalitis of unknown origin affecting the mesencephalon, pons and rostral medulla oblongata. The dog was started on immunosuppressive treatment with prednisolone and cytosine arabinoside, which was subsequently switched to cyclosporine. Narcolepsy-cataplexy episodes could initially still be triggered by offering food; however, they gradually became shorter and less frequent until they completely subsided along with all other clinical signs after 3 wk. No relapse occurred over a 32 mo follow-up period from the diagnosis. Repeated MRI revealed marked reduction in the lesion size; cerebrospinal fluid analysis revealed no abnormalities. Although very rare, symptomatic narcolepsy/cataplexy can occur in dogs and can be secondary to brainstem encephalitis. Cardiovascular changes can occur in association with narcolepsy/cataplexy and should be considered when dealing with patients presenting with these specific clinical signs.
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Affiliation(s)
- Lorenzo Mari
- From the Neurology/Neurosurgery Service, Centre for Small Animal Studies, Animal Health Trust, Suffolk, United Kingdom
| | - Anita Shea
- From the Neurology/Neurosurgery Service, Centre for Small Animal Studies, Animal Health Trust, Suffolk, United Kingdom
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7
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Drissi NM, Warntjes M, Wessén A, Szakacs A, Darin N, Hallböök T, Landtblom AM, Gauffin H, Engström M. Structural anomaly in the reticular formation in narcolepsy type 1, suggesting lower levels of neuromelanin. NEUROIMAGE-CLINICAL 2019; 23:101875. [PMID: 31174102 PMCID: PMC6551567 DOI: 10.1016/j.nicl.2019.101875] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 04/04/2019] [Accepted: 05/25/2019] [Indexed: 12/18/2022]
Abstract
The aim of this study was to investigate structural changes in the brain stem of adolescents with narcolepsy, a disorder characterized by excessive daytime sleepiness, fragmented night-time sleep, and cataplexy. For this purpose, we used quantitative magnetic resonance imaging to obtain R1 and R2 relaxation rates, proton density, and myelin maps in adolescents with narcolepsy (n = 14) and healthy controls (n = 14). We also acquired resting state functional magnetic resonance imaging (fMRI) for brainstem connectivity analysis. We found a significantly lower R2 in the rostral reticular formation near the superior cerebellar peduncle in narcolepsy patients, family wise error corrected p = .010. Narcolepsy patients had a mean R2 value of 1.17 s-1 whereas healthy controls had a mean R2 of 1.31 s-1, which was a large effect size with Cohen d = 4.14. We did not observe any significant differences in R1 relaxation, proton density, or myelin content. The sensitivity of R2 to metal ions in tissue and the transition metal ion chelating property of neuromelanin indicate that the R2 deviant area is one of the neuromelanin containing nuclei of the brain stem. The close proximity and its demonstrated involvement in sleep-maintenance, specifically through orexin projections from the hypothalamus regulating sleep stability, as well as the results from the connectivity analysis, suggest that the observed deviant area could be the locus coeruleus or other neuromelanin containing nuclei in the proximity of the superior cerebellar peduncle. Hypothetically, the R2 differences described in this paper could be due to lower levels of neuromelanin in this area of narcolepsy patients.
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Affiliation(s)
- Natasha Morales Drissi
- Department of Medical and Health Sciences (IMH), Linköping University, 581 83 Linköping, Sweden; Center for Medical Image Science and Visualization, Linköping University, 581 83 Linköping, Sweden
| | - Marcel Warntjes
- Department of Medical and Health Sciences (IMH), Linköping University, 581 83 Linköping, Sweden; Center for Medical Image Science and Visualization, Linköping University, 581 83 Linköping, Sweden
| | | | - Attila Szakacs
- Department of Pediatrics, Queen Silvia Children's Hospital, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, 416 50 Gothenburg, Sweden
| | - Niklas Darin
- Department of Pediatrics, Queen Silvia Children's Hospital, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, 416 50 Gothenburg, Sweden
| | - Tove Hallböök
- Department of Pediatrics, Queen Silvia Children's Hospital, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, 416 50 Gothenburg, Sweden
| | - Anne-Marie Landtblom
- Center for Medical Image Science and Visualization, Linköping University, 581 83 Linköping, Sweden; Department of Clinical and Experimental Medicine (IKE), Linköping University, 581 83 Linköping, Sweden; Department of Neuroscience, Uppsala University, 752 36 Uppsala, Sweden
| | - Helena Gauffin
- Department of Clinical and Experimental Medicine (IKE), Linköping University, 581 83 Linköping, Sweden
| | - Maria Engström
- Department of Medical and Health Sciences (IMH), Linköping University, 581 83 Linköping, Sweden; Center for Medical Image Science and Visualization, Linköping University, 581 83 Linköping, Sweden.
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8
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Abstract
Narcolepsy is the most common neurological cause of chronic sleepiness. The discovery about 20 years ago that narcolepsy is caused by selective loss of the neurons producing orexins (also known as hypocretins) sparked great advances in the field. Here, we review the current understanding of how orexin neurons regulate sleep-wake behaviour and the consequences of the loss of orexin neurons. We also summarize the developing evidence that narcolepsy is an autoimmune disorder that may be caused by a T cell-mediated attack on the orexin neurons and explain how these new perspectives can inform better therapeutic approaches.
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Affiliation(s)
- Carrie E Mahoney
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Andrew Cogswell
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Igor J Koralnik
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
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9
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Imperatore R, D'Angelo L, Safari O, Motlagh HA, Piscitelli F, de Girolamo P, Cristino L, Varricchio E, di Marzo V, Paolucci M. Overlapping Distribution of Orexin and Endocannabinoid Receptors and Their Functional Interaction in the Brain of Adult Zebrafish. Front Neuroanat 2018; 12:62. [PMID: 30104964 PMCID: PMC6077257 DOI: 10.3389/fnana.2018.00062] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/11/2018] [Indexed: 12/31/2022] Open
Abstract
Hypocretins/Orexins neuropeptides are known to regulate numerous physiological functions, such as energy homeostasis, food intake, sleep/wake cycle, arousal and wakefulness, in vertebrates. Previous studies on mice have revealed an intriguing orexins/endocannabinoids (ECs) signaling interaction at both structural and functional levels, with OX-A behaving as a strong enhancer of 2-arachydonoyl-glycerol (2-AG) biosynthesis. In this study, we describe, for the first time in the brain of zebrafish, the anatomical distribution and co-expression of orexin (OX-2R) and endocannabinoid (CB1R) receptors, suggesting a functional interaction. The immunohistochemical colocalization of these receptors by confocal imaging in the dorsal and ventral telencephalon, suprachiasmatic nucleus (SC), thalamus, hypothalamus, preoptic area (PO) and cerebellum, is reported. Moreover, biochemical quantification of 2-AG levels by LC-MS supports the occurrence of OX-A-induced 2-AG biosynthesis in the zebrafish brain after 3 h of OX-A intraperitoneal (i.p.; 3 pmol/g) or intracerebroventricular (i.c.v.; 0.3 pmol/g) injection. This effect is likely mediated by OX-2R as it is counteracted by i.p./i.c.v administration of OX-2R antagonist (SB334867, 10 pmol/g). This study provides compelling morphological and functional evidence of an OX-2R/CB1R signaling interaction in the brain of adult zebrafish, suggesting the use of this well-established vertebrate animal model for the study of complex and phylogenetically conserved physiological functions.
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Affiliation(s)
- Roberta Imperatore
- Department of Science and Technology (DST), University of Sannio, Benevento, Italy.,Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Pozzuoli, Italy
| | - Livia D'Angelo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy.,Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Omid Safari
- Department of Fisheries, Faculty of Natural Resources and Environment, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hamidreza Ahmadniaye Motlagh
- Department of Fisheries, Faculty of Natural Resources and Environment, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Fabiana Piscitelli
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Pozzuoli, Italy
| | - Paolo de Girolamo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy
| | - Luigia Cristino
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Pozzuoli, Italy
| | - Ettore Varricchio
- Department of Science and Technology (DST), University of Sannio, Benevento, Italy
| | - Vincenzo di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Pozzuoli, Italy
| | - Marina Paolucci
- Department of Science and Technology (DST), University of Sannio, Benevento, Italy
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10
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Thompson MD, Sakurai T, Rainero I, Maj MC, Kukkonen JP. Orexin Receptor Multimerization versus Functional Interactions: Neuropharmacological Implications for Opioid and Cannabinoid Signalling and Pharmacogenetics. Pharmaceuticals (Basel) 2017; 10:ph10040079. [PMID: 28991183 PMCID: PMC5748636 DOI: 10.3390/ph10040079] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/29/2017] [Accepted: 09/29/2017] [Indexed: 12/17/2022] Open
Abstract
Orexins/hypocretins are neuropeptides formed by proteolytic cleavage of a precursor peptide, which are produced by neurons found in the lateral hypothalamus. The G protein-coupled receptors (GPCRs) for these ligands, the OX₁ and OX₂ orexin receptors, are more widely expressed throughout the central nervous system. The orexin/hypocretin system has been implicated in many pathways, and its dysregulation is under investigation in a number of diseases. Disorders in which orexinergic mechanisms are being investigated include narcolepsy, idiopathic sleep disorders, cluster headache and migraine. Human narcolepsy has been associated with orexin deficiency; however, it has only rarely been attributed to mutations in the gene encoding the precursor peptide. While gene variations within the canine OX₂ gene hcrtr2 have been directly linked with narcolepsy, the majority of human orexin receptor variants are weakly associated with diseases (the idiopathic sleep disorders, cluster headache and polydipsia-hyponatremia in schizophrenia) or are of potential pharmacogenetic significance. Evidence for functional interactions and/or heterodimerization between wild-type and variant orexin receptors and opioid and cannabinoid receptors is discussed in the context of its relevance to depression and epilepsy.
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Affiliation(s)
- Miles D Thompson
- Department of Pediatrics, University of California, San Diego 92093, CA, USA.
| | - Takeshi Sakurai
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa 920-8620, Japan.
| | - Innocenzo Rainero
- Department of Neuroscience, University of Turin, Torino 10124, Italy.
| | - Mary C Maj
- Department of Biochemistry, School of Medicine, Saint George's University, Saint George's 11739, Grenada.
| | - Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki, Helsinki 11739, Finland.
- Department of Physiology, Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki 00100, Finland.
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12
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Schmid S, Hodshon A, Olin S, Pfeiffer I, Hecht S. Pituitary Macrotumor Causing Narcolepsy-Cataplexy in a Dachshund. J Vet Intern Med 2017; 31:545-549. [PMID: 28090682 PMCID: PMC5354012 DOI: 10.1111/jvim.14640] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/30/2016] [Accepted: 11/21/2016] [Indexed: 12/03/2022] Open
Abstract
Familial narcolepsy secondary to breed‐specific mutations in the hypocretin receptor 2 gene and sporadic narcolepsy associated with hypocretin ligand deficiencies occur in dogs. In this report, a pituitary mass is described as a unique cause of narcolepsy‐cataplexy in a dog. A 6‐year‐old male neutered Dachshund had presented for acute onset of feeding‐induced cataplexy and was found to have a pituitary macrotumor on magnetic resonance imaging (MRI). Cerebral spinal fluid hypocretin‐1 levels were normal, indicating that tumor effect on the ventral lateral nucleus of the hypothalamus was not the cause of the dog's narcolepsy‐cataplexy. The dog was also negative for the hypocretin receptor 2 gene mutation associated with narcolepsy in Dachshunds, ruling out familial narcolepsy. The Dachshund underwent stereotactic radiotherapy (SRT), which resulted in reduction in the mass and coincident resolution of the cataplectic attacks. Nine months after SRT, the dog developed clinical hyperadrenocorticism, which was successfully managed with trilostane. These findings suggest that disruptions in downstream signaling of hypocretin secondary to an intracranial mass effect might result in narcolepsy‐cataplexy in dogs and that brain MRI should be strongly considered in sporadic cases of narcolepsy‐cataplexy.
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Affiliation(s)
- S Schmid
- Department of Small Animal Clinical Sciences, The University of Tennessee College of Veterinary Medicine, Knoxville, TN
| | - A Hodshon
- Department of Small Animal Clinical Sciences, The University of Tennessee College of Veterinary Medicine, Knoxville, TN
| | - S Olin
- Department of Small Animal Clinical Sciences, The University of Tennessee College of Veterinary Medicine, Knoxville, TN
| | - I Pfeiffer
- Department of Small Animal Clinical Sciences, The University of Tennessee College of Veterinary Medicine, Knoxville, TN
| | - S Hecht
- Department of Small Animal Clinical Sciences, The University of Tennessee College of Veterinary Medicine, Knoxville, TN
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13
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D'Angelo L, Castaldo L, de Girolamo P, Lucini C, Paolucci M, Pelagalli A, Varricchio E, Arcamone N. Orexins and receptor OX2R in the gastroenteric apparatus of two teleostean species:Dicentrarchus labraxandCarassius auratus. Anat Rec (Hoboken) 2016; 299:1121-9. [DOI: 10.1002/ar.23374] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 03/25/2016] [Accepted: 04/04/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Livia D'Angelo
- Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; Italy
| | - Luciana Castaldo
- Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; Italy
| | - Paolo de Girolamo
- Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; Italy
| | - Carla Lucini
- Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; Italy
| | - Marina Paolucci
- Department of Sciences and Technologies; University of Sannio; Benevento Italy
| | - Alessandra Pelagalli
- Department of Advanced Biomedical Sciences; University of Naples Federico II; Italy
- Institute of Biostructures and Bioimages; National Research Council; Naples Italy
| | - Ettore Varricchio
- Department of Sciences and Technologies; University of Sannio; Benevento Italy
| | - Nadia Arcamone
- Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; Italy
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14
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Abstract
We previously reported an increased frequency of antibodies to hypocretin (HCRT) receptor 2 in sera obtained from narcoleptic patients who received the European AS03-adjuvanted vaccine Pandemrix (GlaxoSmithKline Biologicals, s.a.) for the global influenza A H1N1 pandemic in 2009 [A(H1N1)pdm09]. These antibodies cross-reacted with a particular fragment of influenza nucleoprotein (NP) - one of the proteins naturally contained in the virus used to make seasonal influenza vaccine and pandemic influenza vaccines. The purpose of this commentary is to provide additional insights and interpretations of the findings and share additional data not presented in the original paper to help the reader appreciate the key messages of that publication. First, a brief background to narcolepsy and vaccine-induced narcolepsy will be provided. Then, additional insights and clarification will be provided on the following topics: 1) the critical difference identified in the adjuvanted A(H1N1)pdm09 vaccines, 2) the contributing factor likely for the discordant association of narcolepsy between the AS03-adjuvanted pandemic vaccines Pandemrix and Arepanrix (GlaxoSmithKline Biologicals, s.a.), 3) the significance of detecting HCRT receptor 2 (HCRTr2) antibodies in some Finnish control subjects, 4) the approach used for the detection of HCRTr2 antibodies in vaccine-associated narcolepsy, and 5) the plausibility of the proposed mechanism involving HCRTr2 modulation in vaccine-associated narcolepsy.
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Affiliation(s)
| | - Lawrence Steinman
- b Neurology and Neuroscience , Stanford University School of Medicine , Stanford , CA , USA
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Ahmed SS, Volkmuth W, Duca J, Corti L, Pallaoro M, Pezzicoli A, Karle A, Rigat F, Rappuoli R, Narasimhan V, Julkunen I, Vuorela A, Vaarala O, Nohynek H, Pasini FL, Montomoli E, Trombetta C, Adams CM, Rothbard J, Steinman L. Antibodies to influenza nucleoprotein cross-react with human hypocretin receptor 2. Sci Transl Med 2016; 7:294ra105. [PMID: 26136476 DOI: 10.1126/scitranslmed.aab2354] [Citation(s) in RCA: 163] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The sleep disorder narcolepsy is linked to the HLA-DQB1*0602 haplotype and dysregulation of the hypocretin ligand-hypocretin receptor pathway. Narcolepsy was associated with Pandemrix vaccination (an adjuvanted, influenza pandemic vaccine) and also with infection by influenza virus during the 2009 A(H1N1) influenza pandemic. In contrast, very few cases were reported after Focetria vaccination (a differently manufactured adjuvanted influenza pandemic vaccine). We hypothesized that differences between these vaccines (which are derived from inactivated influenza viral proteins) explain the association of narcolepsy with Pandemrix-vaccinated subjects. A mimic peptide was identified from a surface-exposed region of influenza nucleoprotein A that shared protein residues in common with a fragment of the first extracellular domain of hypocretin receptor 2. A significant proportion of sera from HLA-DQB1*0602 haplotype-positive narcoleptic Finnish patients with a history of Pandemrix vaccination (vaccine-associated narcolepsy) contained antibodies to hypocretin receptor 2 compared to sera from nonnarcoleptic individuals with either 2009 A(H1N1) pandemic influenza infection or history of Focetria vaccination. Antibodies from vaccine-associated narcolepsy sera cross-reacted with both influenza nucleoprotein and hypocretin receptor 2, which was demonstrated by competitive binding using 21-mer peptide (containing the identified nucleoprotein mimic) and 55-mer recombinant peptide (first extracellular domain of hypocretin receptor 2) on cell lines expressing human hypocretin receptor 2. Mass spectrometry indicated that relative to Pandemrix, Focetria contained 72.7% less influenza nucleoprotein. In accord, no durable antibody responses to nucleoprotein were detected in sera from Focetria-vaccinated nonnarcoleptic subjects. Thus, differences in vaccine nucleoprotein content and respective immune response may explain the narcolepsy association with Pandemrix.
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Affiliation(s)
- Syed Sohail Ahmed
- Global Clinical Sciences, Novartis Vaccines Srl, Siena 53100, Italy.
| | - Wayne Volkmuth
- Informatics and Information Technology, Atreca Inc., Redwood City, CA 94063, USA
| | - José Duca
- Computer-Aided Drug Discovery, Novartis Institutes for BioMedical Research, Cambridge, MA 02139, USA
| | - Lorenzo Corti
- Formulation Analytics, Novartis Vaccines Srl, Siena 53100, Italy
| | - Michele Pallaoro
- Formulation Analytics, Novartis Vaccines Srl, Siena 53100, Italy
| | | | - Anette Karle
- Integrated Biologics Profiling Unit, Novartis Pharma AG, Basel 4057, Switzerland
| | - Fabio Rigat
- Quantitative Sciences, Novartis Vaccines Srl, Siena 53100, Italy
| | | | - Vas Narasimhan
- Development, Novartis Vaccines, Cambridge, MA 02139, USA
| | - Ilkka Julkunen
- National Institute for Health and Welfare (THL), Helsinki 00300, Finland. Virology, University of Turku, Turku 20520, Finland
| | - Arja Vuorela
- National Institute for Health and Welfare (THL), Helsinki 00300, Finland
| | - Outi Vaarala
- National Institute for Health and Welfare (THL), Helsinki 00300, Finland
| | - Hanna Nohynek
- National Institute for Health and Welfare (THL), Helsinki 00300, Finland
| | - Franco Laghi Pasini
- Internal Medicine, Policlinico Santa Maria alle Scotte, Azienda Ospedaliera Universitaria Senese, Siena 53100, Italy. Medical Science, Surgery, and Neuroscience, University of Siena, Siena 53100, Italy
| | - Emanuele Montomoli
- Molecular and Developmental Medicine, University of Siena, Siena 53100, Italy. VisMederi Srl, Siena 53100, Italy
| | - Claudia Trombetta
- Molecular and Developmental Medicine, University of Siena, Siena 53100, Italy
| | - Christopher M Adams
- Stanford University Mass Spectrometry, Stanford University School of Medicine, Palo Alto, CA 94305 USA
| | - Jonathan Rothbard
- Immunology, Stanford University School of Medicine, Palo Alto, CA 94305, USA
| | - Lawrence Steinman
- Neurology and Neuroscience, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Amador A, Wang Y, Banerjee S, Kameneka TM, Solt LA, Burris TP. Pharmacological and Genetic Modulation of REV-ERB Activity and Expression Affects Orexigenic Gene Expression. PLoS One 2016; 11:e0151014. [PMID: 26963516 PMCID: PMC4786293 DOI: 10.1371/journal.pone.0151014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/23/2016] [Indexed: 12/21/2022] Open
Abstract
The nuclear receptors REV-ERBα and REV-ERBβ are transcription factors that play pivotal roles in the regulation of the circadian rhythm and various metabolic processes. The circadian rhythm is an endogenous mechanism, which generates entrainable biological changes that follow a 24-hour period. It regulates a number of physiological processes, including sleep/wakeful cycles and feeding behaviors. We recently demonstrated that REV-ERB-specific small molecules affect sleep and anxiety. The orexinergic system also plays a significant role in mammalian physiology and behavior, including the regulation of sleep and food intake. Importantly, orexin genes are expressed in a circadian manner. Given these overlaps in function and circadian expression, we wanted to determine whether the REV-ERBs might regulate orexin. We found that acute in vivo modulation of REV-ERB activity, with the REV-ERB-specific synthetic ligand SR9009, affects the circadian expression of orexinergic genes in mice. Long term dosing with SR9009 also suppresses orexinergic gene expression in mice. Finally, REV-ERBβ-deficient mice present with increased orexinergic transcripts. These data suggest that the REV-ERBs may be involved in the repression of orexinergic gene expression.
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Affiliation(s)
- Ariadna Amador
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Yongjun Wang
- Department of Pharmacology and Physiology, Saint Louis University, Saint Louis, Missouri, United States of America
| | - Subhashis Banerjee
- Department of Pharmacology and Physiology, Saint Louis University, Saint Louis, Missouri, United States of America
| | - Theodore M. Kameneka
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Laura A. Solt
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Thomas P. Burris
- Department of Pharmacology and Physiology, Saint Louis University, Saint Louis, Missouri, United States of America
- * E-mail:
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Black SW, Yamanaka A, Kilduff TS. Challenges in the development of therapeutics for narcolepsy. Prog Neurobiol 2015; 152:89-113. [PMID: 26721620 DOI: 10.1016/j.pneurobio.2015.12.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 11/14/2015] [Accepted: 12/04/2015] [Indexed: 01/19/2023]
Abstract
Narcolepsy is a neurological disorder that afflicts 1 in 2000 individuals and is characterized by excessive daytime sleepiness and cataplexy-a sudden loss of muscle tone triggered by positive emotions. Features of narcolepsy include dysregulation of arousal state boundaries as well as autonomic and metabolic disturbances. Disruption of neurotransmission through the hypocretin/orexin (Hcrt) system, usually by degeneration of the HCRT-producing neurons in the posterior hypothalamus, results in narcolepsy. The cause of Hcrt neurodegeneration is unknown but thought to be related to autoimmune processes. Current treatments for narcolepsy are symptomatic, including wake-promoting therapeutics that increase presynaptic dopamine release and anticataplectic agents that activate monoaminergic neurotransmission. Sodium oxybate is the only medication approved by the US Food and Drug Administration that alleviates both sleep/wake disturbances and cataplexy. Development of therapeutics for narcolepsy has been challenged by historical misunderstanding of the disease, its many disparate symptoms and, until recently, its unknown etiology. Animal models have been essential to elucidating the neuropathology underlying narcolepsy. These models have also aided understanding the neurobiology of the Hcrt system, mechanisms of cataplexy, and the pharmacology of narcolepsy medications. Transgenic rodent models will be critical in the development of novel therapeutics for the treatment of narcolepsy, particularly efforts directed to overcome challenges in the development of hypocretin replacement therapy.
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Affiliation(s)
- Sarah Wurts Black
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, CA 94025, USA
| | - Akihiro Yamanaka
- Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Thomas S Kilduff
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, CA 94025, USA.
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18
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Maruyama T, Matsumura M, Sakai N, Nishino S. The pathogenesis of narcolepsy, current treatments and prospective therapeutic targets. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2016.1117973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
Initially implicated in the regulation of feeding, orexins/hypocretins are now acknowledged to play a major role in the control of a wide variety of biological processes, such as sleep, energy expenditure, pain, cardiovascular function and neuroendocrine regulation, a feature that makes them one of the most pleiotropic families of hypothalamic neuropeptides. While the orexigenic effect of orexins is well described, their central effects on energy expenditure and particularly on brown adipose tissue (BAT) thermogenesis are not totally unraveled. Better understanding of these actions and their possible interrelationship with other hypothalamic systems controlling thermogenesis, such as AMP-activated protein kinase (AMPK) and endoplasmic reticulum (ER) stress, will help to clarify the exact role and pathophysiological relevance of these neuropeptides have on energy balance.
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Affiliation(s)
- Johan Fernø
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; Department of Clinical Science, K. G. Jebsen Center for Diabetes Research, University of Bergen, N-5021 Bergen, Norway.
| | - Rosa Señarís
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
| | - Carlos Diéguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn) 15706, Spain
| | - Manuel Tena-Sempere
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn) 15706, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Instituto Maimónides de Investigación Biomédica (IMIBIC)/Hospital Reina Sofía, 14004 Córdoba, Spain; FiDiPro Program, Department of Physiology, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn) 15706, Spain.
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20
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Parker HG, Gilbert SF. From caveman companion to medical innovator: genomic insights into the origin and evolution of domestic dogs. ACTA ACUST UNITED AC 2015; 5:239-255. [PMID: 28490917 DOI: 10.2147/agg.s57678] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The phenotypic and behavioral diversity of the domestic dog has yet to be matched by any other mammalian species. In their current form, which comprises more than 350 populations known as breeds, there is a size range of two orders of magnitude and morphological features reminiscent of not only different species but also different phylogenetic families. The range of both appearance and behavior found in the dog is the product of millennia of human interference, and though humans created the diversity it remains a point of fascination to both lay and scientific communities. In this review we summarize the current understanding of the history of dog domestication based on molecular data. We will examine the ways that canine genetic and genomic studies have evolved and look at examples of dog genetics in the light of human disease.
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Affiliation(s)
- Heidi G Parker
- National Human Genome Research Institute, National Institutes of Health, Bethesda MD, 20892 USA
| | - Samuel F Gilbert
- National Human Genome Research Institute, National Institutes of Health, Bethesda MD, 20892 USA
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21
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O'Brien DP, Leeb T. DNA testing in neurologic diseases. J Vet Intern Med 2014; 28:1186-98. [PMID: 24962505 PMCID: PMC4857950 DOI: 10.1111/jvim.12383] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/03/2014] [Accepted: 04/23/2014] [Indexed: 12/24/2022] Open
Abstract
DNA testing is available for a growing number of hereditary diseases in neurology and other specialties. In addition to guiding breeding decisions, DNA tests are important tools in the diagnosis of diseases, particularly in conditions for which clinical signs are relatively nonspecific. DNA testing also can provide valuable insight into the risk of hereditary disease when decisions about treating comorbidities are being made. Advances in technology and bioinformatics will make broad screening for potential disease-causing mutations available soon. As DNA tests come into more common use, it is critical that clinicians understand the proper application and interpretation of these test results.
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Affiliation(s)
- D P O'Brien
- Department Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO
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22
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Thompson MD, Xhaard H, Sakurai T, Rainero I, Kukkonen JP. OX1 and OX2 orexin/hypocretin receptor pharmacogenetics. Front Neurosci 2014; 8:57. [PMID: 24834023 PMCID: PMC4018553 DOI: 10.3389/fnins.2014.00057] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 03/12/2014] [Indexed: 01/01/2023] Open
Abstract
Orexin/hypocretin peptide mutations are rare in humans. Even though human narcolepsy is associated with orexin deficiency, this is only extremely rarely due to mutations in the gene coding prepro-orexin, the precursor for both orexin peptides. In contrast, coding and non-coding variants of the OX1 and OX2 orexin receptors have been identified in many human populations; sometimes, these have been associated with disease phenotype, although most confer a relatively low risk. In most cases, these studies have been based on a candidate gene hypothesis that predicts the involvement of orexins in the relevant pathophysiological processes. In the current review, the known human OX1/HCRTR1 and OX2/HCRTR2 genetic variants/polymorphisms as well as studies concerning their involvement in disorders such as narcolepsy, excessive daytime sleepiness, cluster headache, polydipsia-hyponatremia in schizophrenia, and affective disorders are discussed. In most cases, the functional cellular or pharmacological correlates of orexin variants have not been investigated—with the exception of the possible impact of an amino acid 10 Pro/Ser variant of OX2 on orexin potency—leaving conclusions on the nature of the receptor variant effects speculative. Nevertheless, we present perspectives that could shape the basis for further studies. The pharmacology and other properties of the orexin receptor variants are discussed in the context of GPCR signaling. Since orexinergic therapeutics are emerging, the impact of receptor variants on the affinity or potency of ligands deserves consideration. This perspective (pharmacogenetics) is also discussed in the review.
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Affiliation(s)
- Miles D Thompson
- University of Toronto Epilepsy Research Program, Department of Pharmacology, University of Toronto Toronto, ON, Canada
| | - Henri Xhaard
- Faculty of Pharmacy, Centre for Drug Research, University of Helsinki Helsinki, Finland
| | - Takeshi Sakurai
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University Kanazawa, Japan
| | | | - Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki Helsinki, Finland
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Rainero I, Martino PD, Pinessi L. Hypocretins and primary headaches: neurobiology and clinical implications. Expert Rev Neurother 2014; 8:409-16. [DOI: 10.1586/14737175.8.3.409] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Adeno-associated virus serotypes 9 and rh10 mediate strong neuronal transduction of the dog brain. Gene Ther 2013; 21:28-36. [PMID: 24131981 PMCID: PMC3881028 DOI: 10.1038/gt.2013.54] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 08/23/2013] [Accepted: 08/28/2013] [Indexed: 12/20/2022]
Abstract
Canine models have many advantages for evaluating therapy of human central nervous system (CNS) diseases. In contrast to nonhuman primate models, naturally occurring canine CNS diseases are common. In contrast to murine models, the dog's lifespan is long, its brain is large and the diseases affecting it commonly have the same molecular, pathological and clinical phenotype as the human diseases. We compared the ability of four intracerebrally injected adeno-associated virus vector (AAV) serotypes to transduce the dog brain with green fluorescent protein as the first step in using these vectors to evaluate both delivery and efficacy in naturally occurring canine homologs of human diseases. Quantitative measures of transduction, maximum diameter and area, identified both AAV2/9 and AAV2/rh10 as significantly more efficient than either AAV2/1 or AAV2/5 at transducing cerebral cortex, caudate nucleus, thalamus and internal capsule. Fluorescence co-labeling with cell-type-specific antibodies demonstrated that AAV2/9 and AAV2/rh10 were capable of primarily transducing neurons, although glial transduction was also identified and found to be more efficient with the AAV2/9 vector. These data are a prerequisite to evaluating the efficacy of recombinant AAV vectors carrying disease-modifying transgenes to treat naturally occurring canine models in preclinical studies of human CNS disease therapy.
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Burgess C, Peever J. A Noradrenergic Mechanism Functions to Couple Motor Behavior with Arousal State. Curr Biol 2013; 23:1719-25. [DOI: 10.1016/j.cub.2013.07.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/03/2013] [Accepted: 07/03/2013] [Indexed: 10/26/2022]
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Dong XS, Ma SF, Cao CW, Li J, An P, Zhao L, Liu NY, Yan H, Hu QT, Mignot E, Strohl KP, Gao ZC, Zeng C, Han F. Hypocretin (orexin) neuropeptide precursor gene, HCRT, polymorphisms in early-onset narcolepsy with cataplexy. Sleep Med 2013; 14:482-7. [PMID: 23643651 DOI: 10.1016/j.sleep.2013.01.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/18/2013] [Accepted: 01/25/2013] [Indexed: 01/21/2023]
Abstract
BACKGROUND To test if the hypocretin (orexin) neuropeptide precursor (HCRT) gene, HCRT, mutations are implicated in the development of narcolepsy with cataplexy deficiency in young children. METHODS The entire HCRT gene and ~2000 bp promoter region was first sequenced in 181 patients and 153 controls, and rare polymorphisms including three nonsynonymous amino acid changes were identified. Next the 557 bp region of exon 2 harboring the three nonsynonymous changes was sequenced in an additional 298 early-onset subjects and in 148 control samples. RESULTS A previously known common polymorphism (rs760282) and nine rare novel polymorphisms were identified in subjects and controls without significant differences. Two nonsynonymous exon 2 substitutions (+977 H54A, +979 G55R) were detected in two subjects with early onset at 7 and 6 years, respectively, but were not found in any controls. These substitutions are not likely to vastly change peptide binding to hypocretin receptors. One additional exon 2 substitution (+1019, K68R) was found in two patients and one control. Additional sequencing that focused on exon 2 showed additional subjects and controls with the +1019 K68R polymorphism and without significant differences between the subjects and the control. Segregation of two of these three nonsynonymous single nucleotide polymorphisms (SNPs) were observed from unaffected parents to offspring. CONCLUSIONS Sequencing of a large number of early-onset narcolepsy subjects revealed three novel nonsynonymous substitutions within the preprohypocretin protein, two of which were only found in patients with early-onset narcolepsy but are not likely to be functionally significant, especially in heterozygote subjects.
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Affiliation(s)
- Xiao Song Dong
- Department of Pulmonary Medicine, Beijing University People's Hospital, Beijing, China
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27
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Kukkonen JP. Physiology of the orexinergic/hypocretinergic system: a revisit in 2012. Am J Physiol Cell Physiol 2012; 304:C2-32. [PMID: 23034387 DOI: 10.1152/ajpcell.00227.2012] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The neuropeptides orexins and their G protein-coupled receptors, OX(1) and OX(2), were discovered in 1998, and since then, their role has been investigated in many functions mediated by the central nervous system, including sleep and wakefulness, appetite/metabolism, stress response, reward/addiction, and analgesia. Orexins also have peripheral actions of less clear physiological significance still. Cellular responses to the orexin receptor activity are highly diverse. The receptors couple to at least three families of heterotrimeric G proteins and other proteins that ultimately regulate entities such as phospholipases and kinases, which impact on neuronal excitation, synaptic plasticity, and cell death. This article is a 10-year update of my previous review on the physiology of the orexinergic/hypocretinergic system. I seek to provide a comprehensive update of orexin physiology that spans from the molecular players in orexin receptor signaling to the systemic responses yet emphasizing the cellular physiological aspects of this system.
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Affiliation(s)
- Jyrki P Kukkonen
- Dept. of Veterinary Biosciences, University of Helsinki, Finland.
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28
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Gotter AL, Webber AL, Coleman PJ, Renger JJ, Winrow CJ. International Union of Basic and Clinical Pharmacology. LXXXVI. Orexin Receptor Function, Nomenclature and Pharmacology. Pharmacol Rev 2012; 64:389-420. [DOI: 10.1124/pr.111.005546] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Winrow CJ, Gotter AL, Cox CD, Tannenbaum PL, Garson SL, Doran SM, Breslin MJ, Schreier JD, Fox SV, Harrell CM, Stevens J, Reiss DR, Cui D, Coleman PJ, Renger JJ. Pharmacological characterization of MK-6096 – A dual orexin receptor antagonist for insomnia. Neuropharmacology 2012; 62:978-87. [DOI: 10.1016/j.neuropharm.2011.10.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 08/26/2011] [Accepted: 10/04/2011] [Indexed: 01/02/2023]
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De la Herrán-Arita AK, Drucker-Colín R. Models for narcolepsy with cataplexy drug discovery. Expert Opin Drug Discov 2012; 7:155-64. [DOI: 10.1517/17460441.2012.651454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Shahid IZ, Rahman AA, Pilowsky PM. Orexin and Central Regulation of Cardiorespiratory System. SLEEP HORMONES 2012; 89:159-84. [DOI: 10.1016/b978-0-12-394623-2.00009-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Nixon JP, Kotz CM, Novak CM, Billington CJ, Teske JA. Neuropeptides controlling energy balance: orexins and neuromedins. Handb Exp Pharmacol 2012:77-109. [PMID: 22249811 DOI: 10.1007/978-3-642-24716-3_4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In this chapter, we review the feeding and energy expenditure effects of orexin (also known as hypocretin) and neuromedin. Orexins are multifunctional neuropeptides that affect energy balance by participating in regulation of appetite, arousal, and spontaneous physical activity. Central orexin signaling for all functions originates in the lateral hypothalamus-perifornical area and is likely functionally differentiated based on site of action and on interacting neural influences. The effect of orexin on feeding is likely related to arousal in some ways but is nonetheless a separate neural process that depends on interactions with other feeding-related neuropeptides. In a pattern distinct from other neuropeptides, orexin stimulates both feeding and energy expenditure. Orexin increases in energy expenditure are mainly by increasing spontaneous physical activity, and this energy expenditure effect is more potent than the effect on feeding. Global orexin manipulations, such as in transgenic models, produce energy balance changes consistent with a dominant energy expenditure effect of orexin. Neuromedins are gut-brain peptides that reduce appetite. There are gut sources of neuromedin, but likely the key appetite-related neuromedin-producing neurons are in the hypothalamus and parallel other key anorectic neuropeptide expression in the arcuate to paraventricular hypothalamic projection. As with other hypothalamic feeding-related peptides, hindbrain sites are likely also important sources and targets of neuromedin anorectic action. Neuromedin increases physical activity in addition to reducing appetite, thus producing a consistent negative energy balance effect. Together with the other various neuropeptides, neurotransmitters, neuromodulators, and neurohormones, neuromedin and orexin act in the appetite network to produce changes in food intake and energy expenditure, which ultimately influences the regulation of body weight.
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Affiliation(s)
- Joshua P Nixon
- Veterans Affairs Medical Center, Research Service (151), Minneapolis, MN, USA
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Putula J, Turunen PM, Johansson L, Näsman J, Ra R, Korhonen L, Kukkonen JP. Orexin/hypocretin receptor chimaeras reveal structural features important for orexin peptide distinction. FEBS Lett 2011; 585:1368-74. [DOI: 10.1016/j.febslet.2011.04.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 04/07/2011] [Indexed: 01/04/2023]
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Wong KKY, Ng SYL, Lee LTO, Ng HKH, Chow BKC. Orexins and their receptors from fish to mammals: a comparative approach. Gen Comp Endocrinol 2011; 171:124-30. [PMID: 21216246 DOI: 10.1016/j.ygcen.2011.01.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 12/28/2010] [Accepted: 01/01/2011] [Indexed: 12/12/2022]
Abstract
Although recently discovered, orexins have been rapidly established as important neuropeptides in regulating physiological processes including food intake, sleep/wake cycles and reproduction through binding to two class B G protein-coupled receptors (OX1R and OX2R). To date, a handful of sequences for orexins and their receptors ranging from fish to mammalian species have been identified, allowing a glimpse into their evolution. Structurally, the genetic and molecular organization of the peptides and receptors amongst vertebrates are highly similar, underlining the strong evolutionary pressure that has been exerted to preserve structure and ultimately function. Furthermore, the absence of invertebrate orexin-like sequences suggests early vertebrates as the origin from which orexins evolved. With respect to the receptors, OX2R is probably evolutionary more ancient whilst OX1R is specific to mammalian species and evolved only during this later lineage. In common to all vertebrates studied, the hypothalamus remains to be the key brain region in which orexinergic neurons and fibers are localized in, establishing orexin to be an important player in regulating physiological processes especially those related to food intake and energy metabolism. To allow better understanding of the evolution of orexins and their receptors, this review will provide a comparative approach to their structures and functions in vertebrates.
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Affiliation(s)
- Kari K Y Wong
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
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Parker HG, Shearin AL, Ostrander EA. Man's best friend becomes biology's best in show: genome analyses in the domestic dog. Annu Rev Genet 2011; 44:309-36. [PMID: 21047261 DOI: 10.1146/annurev-genet-102808-115200] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In the last five years, canine genetics has gone from map construction to complex disease deconstruction. The availability of a draft canine genome sequence, dense marker chips, and an understanding of the genome architecture has changed the types of studies canine geneticists can undertake. There is now a clear recognition that the dog system offers the opportunity to understand the genetics of both simple and complex traits, including those associated with morphology, disease susceptibility, and behavior. In this review, we summarize recent findings regarding canine domestication and review new information on the organization of the canine genome. We discuss studies aimed at finding genes controlling morphological phenotypes and provide examples of the way such paradigms may be applied to studies of behavior. We also discuss the many ways in which the dog has illuminated our understanding of human disease and conclude with a discussion on where the field is likely headed in the next five years.
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Affiliation(s)
- Heidi G Parker
- Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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Bhagwandin A, Fuxe K, Bennett NC, Manger PR. Distribution of orexinergic neurons and their terminal networks in the brains of two species of African mole rats. J Chem Neuroanat 2011; 41:32-42. [DOI: 10.1016/j.jchemneu.2010.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 11/01/2010] [Accepted: 11/03/2010] [Indexed: 10/18/2022]
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Affiliation(s)
- Seiji Nishino
- Stanford University School of Medicine, Stanford Sleep Research Center, Palo Alto, CA, USA.
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Shearin AL, Ostrander EA. Leading the way: canine models of genomics and disease. Dis Model Mech 2010; 3:27-34. [PMID: 20075379 DOI: 10.1242/dmm.004358] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In recent years Canis familiaris, the domestic dog, has drawn considerable attention as a system in which to investigate the genetics of disease susceptibility, morphology and behavior. Because dogs show remarkable intrabreed homogeneity, coupled with striking interbreed heterogeneity, the dog offers unique opportunities to understand the genetic underpinnings of natural variation in mammals, a portion of which is disease susceptibility. In this review, we highlight the unique features of the dog, such as population diversity and breed structure, that make it particularly amenable to genetic studies. We highlight recent advances in understanding the architecture of the dog genome, which propel the system to the forefront of consideration when selecting a system for disease gene studies. The most notable benefit of using the dog for genetic studies is that dogs get many of the same diseases as humans, with a similar frequency, and the same genetic factors are often involved. We discuss two approaches for localizing disease genes in the dog and provide examples of ongoing studies.
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Affiliation(s)
- Abigail L Shearin
- Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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DeMartinis NA, Kamath J, Winokur A. New approaches for the treatment of sleep disorders. ADVANCES IN PHARMACOLOGY 2009; 57:187-235. [PMID: 20230762 DOI: 10.1016/s1054-3589(08)57005-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Epidemiological studies have established that sleep disorders are common and often untreated. Besides having a negative impact on overall health, these conditions can significantly disrupt normal daily functions. While a number of drugs are employed in the treatment of sleep disorders, safety, tolerability, and variable efficacy limit their utility. Clinical developments in the area have been facilitated especially by advances in neurobiology and neuropharmacology. In this regard, a wide array of neuroactive substances has been found to be responsible for regulating sleep and wakefulness. Advances in the understanding of neurotransmitter and hormone receptor mechanisms and classifications have led to new opportunities for developing novel therapeutics for treating sleep disorders. Provided in this report is an overview of some of the more prevalent sleep disorders, including narcolepsy, insomnia, obstructive sleep apnea syndrome, and restless legs syndrome, with a summary and critique of medications used to treat these conditions. For each disorder, information is provided on recent approaches taken to develop novel therapeutics based on laboratory findings relating to the underlying biological abnormalities associated with the condition, in addition to approaches that leverage existing therapeutics to develop new treatment options for patients. Significant advances in the future await a better understanding of the underlying pathophysiology of these conditions and of the neurobiological alterations associated with these disorders. It is hoped that some of the research directions described herein will stimulate additional research in this area and thereby help foster the discovery of novel agents for treating major sleep disorders.
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Affiliation(s)
- Nicholas A DeMartinis
- Neuroscience Research Unit, Pfizer, Inc., Eastern Point Rd., Groton, Connecticut 06340, USA
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40
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Chen L, Brown RE, McKenna JT, McCarley RW. Animal models of narcolepsy. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2009; 8:296-308. [PMID: 19689311 DOI: 10.2174/187152709788921717] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Narcolepsy is a debilitating sleep disorder with excessive daytime sleepiness and cataplexy as its two major symptoms. Although this disease was first described about one century ago, an animal model was not available until the 1970s. With the establishment of the Stanford canine narcolepsy colony, researchers were able to conduct multiple neurochemical studies to explore the pathophysiology of this disease. It was concluded that there was an imbalance between monoaminergic and cholinergic systems in canine narcolepsy. In 1999, two independent studies revealed that orexin neurotransmission deficiency was pivotal to the development of narcolepsy with cataplexy. This scientific leap fueled the generation of several genetically engineered mouse and rat models of narcolepsy. To facilitate further research, it is imperative that researchers reach a consensus concerning the evaluation of narcoleptic behavioral and EEG phenomenology in these models.
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Affiliation(s)
- Lichao Chen
- Research Service, VA Boston Healthcare System, Department of Psychiatry, Harvard Medical School, Brockton, MA 02301, USA.
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41
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Cole AG, Stroke IL, Qin LY, Hussain Z, Simhadri S, Brescia MR, Waksmunski FS, Strohl B, Tellew JE, Williams JP, Saunders J, Appell KC, Henderson I, Webb ML. Synthesis of (3,4-dimethoxyphenoxy)alkylamino acetamides as orexin-2 receptor antagonists. Bioorg Med Chem Lett 2008; 18:5420-3. [DOI: 10.1016/j.bmcl.2008.09.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 09/05/2008] [Accepted: 09/09/2008] [Indexed: 11/17/2022]
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Patterson EE, Minor KM, Tchernatynskaia AV, Taylor SM, Shelton GD, Ekenstedt KJ, Mickelson JR. A canine DNM1 mutation is highly associated with the syndrome of exercise-induced collapse. Nat Genet 2008; 40:1235-9. [PMID: 18806795 DOI: 10.1038/ng.224] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Accepted: 07/01/2008] [Indexed: 11/09/2022]
Abstract
Labrador retrievers are the most common dog breed in the world, with over 200,000 new kennel club registrations per year. The syndrome of exercise-induced collapse (EIC) in this breed is manifested by muscle weakness, incoordination and life-threatening collapse after intense exercise. Using a genome-wide microsatellite marker scan for linkage in pedigrees, we mapped the EIC locus to canine chromosome 9. We then used SNP association and haplotype analysis to fine map the locus, and identified a mutation in the dynamin 1 gene (DNM1) that causes an R256L substitution in a highly conserved region of the protein. This first documented mammalian DNM1 mutation is present at a high frequency in the breed and is a compelling candidate causal mutation for EIC, as the dynamin 1 protein has an essential role in neurotransmission and synaptic vesicle endocytosis.
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Affiliation(s)
- Edward E Patterson
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, Minnesota 55108, USA.
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Abstract
Narcolepsy with cataplexy is a debilitating sleep disorder with an estimated prevalence of about 0.05%. Narcolepsy is caused by a selective loss of hypocretin (orexin) producing neurons in the perifornical hypothalamus. Based on the very strong association with the HLA subtype DQB1*0602, it is currently hypothesized narcolepsy is caused by an autoimmune-mediated process directed at the hypocretin neurons. So far however, studies focusing on general markers of (auto)immune activation, as well as humoral immunity against the hypocretin system have not yielded consistent results supporting this hypothesis.
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Affiliation(s)
- Sebastiaan Overeem
- Department of Neurology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
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44
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Teske JA, Billington CJ, Kotz CM. Neuropeptidergic mediators of spontaneous physical activity and non-exercise activity thermogenesis. Neuroendocrinology 2008; 87:71-90. [PMID: 17984627 DOI: 10.1159/000110802] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 09/20/2007] [Indexed: 01/29/2023]
Abstract
Lean individuals have high levels of spontaneous physical activity (SPA) and the energy expenditure derived from that activity, termed non-exercise activity thermogenesis or NEAT, appears to protect them from obesity. Conversely, obesity in different human populations is characterized by low levels of SPA and NEAT. Like in humans, elevated SPA in rats appears to protect against obesity: obesity-resistant rats have significantly greater SPA and NEAT than obesity-prone rats. We review the literature on brain mechanisms important in mediating SPA and NEAT. The focus is on neuropeptides, including cholecystokinin, corticotropin-releasing hormone (also known as corticotropin-releasing factor), neuromedin U, neuropeptide Y, leptin, agouti-related protein, orexin-A (also known as hypocretin-1), and ghrelin. We also review information regarding interactions between these neuropeptides and dopamine, a neurotransmitter important in mediating motor function. Finally, we present evidence that elevated signaling of pathways mediating SPA and NEAT may protect against weight gain and obesity.
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Affiliation(s)
- J A Teske
- VA Medical Center, University of Minnesota, Minneapolis, MN 55417, USA
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Quinnell TG, Farooqi IS, Smith IE, Shneerson JM. Screening the human prepro-orexin gene in a single-centre narcolepsy cohort. Sleep Med 2007; 8:498-502. [PMID: 17576097 DOI: 10.1016/j.sleep.2006.11.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 11/13/2006] [Accepted: 11/25/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND AND PURPOSE Although the orexin system has an established role in narcolepsy, the mechanism of orexin deficiency in human cases is unknown. The strong association with human leukocyte antigen (HLA) DQB1*0602 suggests an autoimmune basis, but supporting evidence is lacking. Although data indicate that HLA status is not the sole genetic factor, only a single case of a functional orexin system mutation has been discovered, in a study with a selection bias designed to increase yield. In this study, we examined the prepro-orexin gene for mutations in a cohort of unrelated patients with narcolepsy from a national UK referral centre. PATIENTS AND METHODS Subjects with a diagnosis of narcolepsy were recruited from a patient database. DNA samples were obtained using buccal smear kits. The prepro-orexin gene was amplified using polymerase chain reactions and screened for polymorphisms and mutations. RESULTS Eighty-one patients were recruited, of whom 69 provided DNA samples. A previously described intronic single nucleotide polymorphism, of unlikely significance, was identified in one subject who had typical clinical and electrophysiological features of narcolepsy. It was located 16 base pairs downstream from exon 1. No other mutations were found. CONCLUSION This result supports existing evidence which indicates that mutations of the prepro-orexin gene are rare and that the genetic contribution to the aetiology of human narcolepsy is likely to be complex.
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Affiliation(s)
- Timothy G Quinnell
- Respiratory Support and Sleep Centre, Papworth Hospital, Papworth Everard, Cambridgeshire, UK.
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46
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Tsai KL, Clark LA, Murphy KE. Understanding hereditary diseases using the dog and human as companion model systems. Mamm Genome 2007; 18:444-51. [PMID: 17653794 PMCID: PMC1998873 DOI: 10.1007/s00335-007-9037-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Accepted: 05/15/2007] [Indexed: 12/22/2022]
Abstract
Animal models are requisite for genetic dissection of, and improved treatment regimens for, human hereditary diseases. While several animals have been used in academic and industrial research, the primary model for dissection of hereditary diseases has been the many strains of the laboratory mouse. However, given its greater (than the mouse) genetic similarity to the human, high number of naturally occurring hereditary diseases, unique population structure, and the availability of the complete genome sequence, the purebred dog has emerged as a powerful model for study of diseases. The major advantage the dog provides is that it is afflicted with approximately 450 hereditary diseases, about half of which have remarkable clinical similarities to corresponding diseases of the human. In addition, humankind has a strong desire to cure diseases of the dog so these two facts make the dog an ideal clinical and genetic model. This review highlights several of these shared hereditary diseases. Specifically, the canine models discussed herein have played important roles in identification of causative genes and/or have been utilized in novel therapeutic approaches of interest to the dog and human.
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Affiliation(s)
- Kate L. Tsai
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843-4467 USA
| | - Leigh Anne Clark
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843-4467 USA
| | - Keith E. Murphy
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843-4467 USA
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Nixon JP, Smale L. A comparative analysis of the distribution of immunoreactive orexin A and B in the brains of nocturnal and diurnal rodents. Behav Brain Funct 2007; 3:28. [PMID: 17567902 PMCID: PMC1913054 DOI: 10.1186/1744-9081-3-28] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2006] [Accepted: 06/13/2007] [Indexed: 12/02/2022] Open
Abstract
Background The orexins (hypocretins) are a family of peptides found primarily in neurons in the lateral hypothalamus. Although the orexinergic system is generally thought to be the same across species, the orexins are involved in behaviors which show considerable interspecific variability. There are few direct cross-species comparisons of the distributions of cells and fibers containing these peptides. Here, we addressed the possibility that there might be important species differences by systematically examining and directly comparing the distribution of orexinergic neurons and fibers within the forebrains of species with very different patterns of sleep-wake behavior. Methods We compared the distribution of orexin-immunoreactive cell bodies and fibers in two nocturnal species (the lab rat, Rattus norvegicus and the golden hamster, Mesocricetus auratus) and two diurnal species (the Nile grass rat, Arvicanthis niloticus and the degu, Octodon degus). For each species, tissue from the olfactory bulbs through the brainstem was processed for immunoreactivity for orexin A and orexin B (hypocretin-1 and -2). The distribution of orexin-positive cells was noted for each species. Orexin fiber distribution and density was recorded and analyzed using a principal components factor analysis to aid in evaluating potential species differences. Results Orexin-positive cells were observed in the lateral hypothalamic area of each species, though there were differences with respect to distribution within this region. In addition, cells positive for orexin A but not orexin B were observed in the paraventricular nucleus of the lab rat and grass rat, and in the supraoptic nucleus of the lab rat, grass rat and hamster. Although the overall distributions of orexin A and B fibers were similar in the four species, some striking differences were noted, especially in the lateral mammillary nucleus, ventromedial hypothalamic nucleus and flocculus. Conclusion The orexin cell and fiber distributions observed in this study were largely consistent with those described in previous studies. However, the present study shows significant species differences in the distribution of orexin cell bodies and in the density of orexin-IR fibers in some regions. Finally, we note previously undescribed populations of orexin-positive neurons outside the lateral hypothalamus in three of the four species examined.
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Affiliation(s)
- Joshua P Nixon
- Department of Zoology, Michigan State University, 203 Natural Science Building, East Lansing, MI 48824-1115 USA
- Department of Food Science and Nutrition and Minnesota Craniofacial Research Training Program (MinnCResT), 17-164 Moos Tower, 515 Delaware St. SE, Minneapolis, MN 55455-0357 USA
| | - Laura Smale
- Department of Zoology, Michigan State University, 203 Natural Science Building, East Lansing, MI 48824-1115 USA
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Abstract
Narcolepsy is characterized by excessive daytime sleepiness (EDS), cataplexy and/or other dissociated manifestations of rapid eye movement (REM) sleep (hypnagogic hallucinations and sleep paralysis). Narcolepsy is currently treated with amphetamine-like central nervous system (CNS) stimulants (for EDS) and antidepressants (for cataplexy). Some other classes of compounds such as modafinil (a non-amphetamine wake-promoting compound for EDS) and gamma-hydroxybutyrate (GHB, a short-acting sedative for EDS/fragmented nighttime sleep and cataplexy) given at night are also employed. The major pathophysiology of human narcolepsy has been recently elucidated based on the discovery of narcolepsy genes in animals. Using forward (i.e., positional cloning in canine narcolepsy) and reverse (i.e., mouse gene knockout) genetics, the genes involved in the pathogenesis of narcolepsy (hypocretin/orexin ligand and its receptor) in animals have been identified. Hypocretins/orexins are novel hypothalamic neuropeptides also involved in various hypothalamic functions such as energy homeostasis and neuroendocrine functions. Mutations in hypocretin-related genes are rare in humans, but hypocretin-ligand deficiency is found in many narcolepsy-cataplexy cases. In this review, the clinical, pathophysiological and pharmacological aspects of narcolepsy are discussed.
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Affiliation(s)
- Seiji Nishino
- Stanford University School of Medicine, Department of Psychiatry and Behavioral Sciences, Sleep and Circadian, Neurobiology Laboratory, Center for Narcolepsy, 1201 Welch Road, P213, Palo Alto, CA 94304, USA.
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Abstract
Cataplexy is one of the most pathognomonic symptoms in narcolepsy. This study was designed to investigate the frequency of the HLA-DQB1 allele and cerebrospinal fluid (CSF) hypocretin levels in Korean narcoleptics with cataplexy as compared with those who do not have cataplexy. Seventy-two narcoleptics were selected based on polysomnography and multiple sleep latency test as well as their history and clinical symptoms at Sleep Disorders Clinic. The patients were divided into a narcolepsy with cataplexy group (n=56) and a narcolepsy without cataplexy group (n=16). All patients were subjected to HLA typing to determine the frequency of DQB1 allele and to spinal tapping to measure the level of CSF hypocretin. In cataplexy-positive patients, as compared with cataplexy-negative patients, the frequency of HLA-DQB1*0602 was found to be significantly high (89.3% vs. 50.0%) (p=0.003). On the other hand, the frequency of HLA-DQB1*0601 was found to be significantly low (0% vs. 43.8%) (p<0.001). In 48 of 56 cataplexy-positive patients (85.7 %), hypocretin levels were decreased (<or=110 pg/mL). However, only 6 of 16 cataplexy-negative patients (37.5%) exhibited a decreased hyopcretin level (p<0.001). The high frequency of HLA-DQB1*0602, low frequency of HLA-DQB1*0601 and low hypocretin levels in cataplexy-positive groups suggest that cataplexy-positive narcolepsy might be an etiologically different disease entity from the cataplexy-negative.
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Affiliation(s)
- Jong-Hyun Jeong
- Department of Neuropsychiatry, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea
| | - Seung-Chul Hong
- Department of Neuropsychiatry, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea
| | - Yoon-Kyung Shin
- Department of Neuropsychiatry, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea
| | - Jin-Hee Han
- Department of Neuropsychiatry, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea
| | - Sung-Pil Lee
- Department of Neuropsychiatry, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea
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Chung S, Civelli O. Orphan neuropeptides. Novel neuropeptides modulating sleep or feeding. Neuropeptides 2006; 40:233-43. [PMID: 16814380 DOI: 10.1016/j.npep.2006.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Revised: 04/12/2006] [Accepted: 04/14/2006] [Indexed: 10/24/2022]
Abstract
Neuropeptides form the largest family of modulators of synaptic transmission. Until 1995 some 60 different neuropeptides had been found. With the recognition that all neuropeptides act by binding to G protein coupled receptors (GPCRs), a new approach relying on the use of orphan GPCRs as targets was designed to identify novel neuropeptides. Thirteen new neuropeptide families have since been discovered. In this review we will describe the orphan GPCR-based approach that led to these discoveries and present its impact on two specific physiological responses, feeding and sleep. In particular, we will discuss the modulatory roles of the hypocretins/orexins and of neuropeptide S in sleep and awakening and those of ghrelin and melanin concentrating hormone in food intake.
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Affiliation(s)
- Shinjae Chung
- Department of Pharmacology, University of California Irvine, Irvine, CA 92697, USA
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