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Leu CL, Lam DD, Salminen AV, Wefers B, Becker L, Garrett L, Rozman J, Wurst W, Hrabě de Angelis M, Hölter SM, Winkelmann J, Williams RH. A patient-enriched MEIS1 coding variant causes a restless legs syndrome-like phenotype in mice. Sleep 2024; 47:zsae015. [PMID: 38314840 DOI: 10.1093/sleep/zsae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 12/10/2023] [Indexed: 02/07/2024] Open
Abstract
Restless legs syndrome (RLS) is a neurological disorder characterized by uncomfortable or unpleasant sensations in the legs during rest periods. To relieve these sensations, patients move their legs, causing sleep disruption. While the pathogenesis of RLS has yet to be resolved, there is a strong genetic association with the MEIS1 gene. A missense variant in MEIS1 is enriched sevenfold in people with RLS compared to non-affected individuals. We generated a mouse line carrying this mutation (p.Arg272His/c.815G>A), referred to herein as Meis1R272H/R272H (Meis1 point mutation), to determine whether it would phenotypically resemble RLS. As women are more prone to RLS, driven partly by an increased risk of developing RLS during pregnancy, we focused on female homozygous mice. We evaluated RLS-related outcomes, particularly sensorimotor behavior and sleep, in young and aged mice. Compared to noncarrier littermates, homozygous mice displayed very few differences. Significant hyperactivity occurred before the lights-on (rest) period in aged female mice, reflecting the age-dependent incidence of RLS. Sensory experiments involving tactile feedback (rotarod, wheel running, and hotplate) were only marginally different. Overall, RLS-like phenomena were not recapitulated except for the increased wake activity prior to rest. This is likely due to the focus on young mice. Nevertheless, the Meis1R272H mouse line is a potentially useful RLS model, carrying a clinically relevant variant and showing an age-dependent phenotype.
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Affiliation(s)
- Chia-Luen Leu
- Institute of Neurogenomics, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Daniel D Lam
- Institute of Neurogenomics, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Aaro V Salminen
- Institute of Neurogenomics, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Benedikt Wefers
- Institute of Developmental Genetics, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Lore Becker
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Center Munich, Neuherberg, Germany
| | - Lillian Garrett
- Institute of Developmental Genetics, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Center Munich, Neuherberg, Germany
| | - Jan Rozman
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Belvaux, Luxembourg
| | - Wolfgang Wurst
- Institute of Developmental Genetics, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Site Munich, Germany
- Chair of Developmental Genetics, TUM School of Life Sciences, Technische Universität München, Freising, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Martin Hrabě de Angelis
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Chair of Experimental Genetics, TUM School of Life Sciences, Technische Universität, München, Freising, Germany
| | - Sabine M Hölter
- Institute of Developmental Genetics, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Rhîannan H Williams
- Institute of Neurogenomics, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
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2
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Zeng P, Wang T, Zhang L, Guo F. Exploring the causes of augmentation in restless legs syndrome. Front Neurol 2023; 14:1160112. [PMID: 37840917 PMCID: PMC10571710 DOI: 10.3389/fneur.2023.1160112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 09/13/2023] [Indexed: 10/17/2023] Open
Abstract
Long-term drug treatment for Restless Legs Syndrome (RLS) patients can frequently result in augmentation, which is the deterioration of symptoms with an increased drug dose. The cause of augmentation, especially derived from dopamine therapy, remains elusive. Here, we review recent research and clinical progress on the possible mechanism underlying RLS augmentation. Dysfunction of the dopamine system highly possibly plays a role in the development of RLS augmentation, as dopamine agonists improve desensitization of dopamine receptors, disturb receptor interactions within or outside the dopamine receptor family, and interfere with the natural regulation of dopamine synthesis and release in the neural system. Iron deficiency is also indicated to contribute to RLS augmentation, as low iron levels can affect the function of the dopamine system. Furthermore, genetic risk factors, such as variations in the BTBD9 and MEIS1 genes, have been linked to an increased risk of RLS initiation and augmentation. Additionally, circadian rhythm, which controls the sleep-wake cycle, may also contribute to the worsening of RLS symptoms and the development of augmentation. Recently, Vitamin D deficiency has been suggested to be involved in RLS augmentation. Based on these findings, we propose that the progressive reduction of selective receptors, influenced by various pathological factors, reverses the overcompensation of the dopamine intensity promoted by short-term, low-dose dopaminergic therapy in the development of augmentation. More research is needed to uncover a deeper understanding of the mechanisms underlying the RLS symptom and to develop effective RLS augmentation treatments.
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Affiliation(s)
- Pengyu Zeng
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Tiantian Wang
- Department of Pharmacy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Center for Sleep Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Lisan Zhang
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Center for Sleep Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Fang Guo
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
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3
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Woods S, Basco J, Clemens S. Effects of iron-deficient diet on sleep onset and spinal reflexes in a rodent model of Restless Legs Syndrome. Front Neurol 2023; 14:1160028. [PMID: 37273717 PMCID: PMC10234126 DOI: 10.3389/fneur.2023.1160028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 05/02/2023] [Indexed: 06/06/2023] Open
Abstract
Restless Legs Syndrome (RLS) is a common sensorimotor and a sleep disorder that affects 2.5-10% of the European and North American populations. RLS is also often associated with periodic leg movements during sleep (PLMS). Despite ample evidence of genetic contributions, the underlying mechanisms that elicit the sensory and motor symptoms remain unidentified. Clinically, RLS has been correlated with an altered central iron metabolism, particularly in the brain. While several animal models have been developed to determine the outcome of an altered iron homeostasis on brain function, the potential role of an altered iron homeostasis on sleep and sensorimotor circuits has not yet been investigated. Here, we utilize a mouse model to assess the effects of an iron-deficient (ID) but non-anemic state on sleep time and episodes, and sensorimotor reflexes in male and female mice. We found that animals on the ID diet displayed an increased expression of the transferrin receptor in the spinal cord, confirming the results of previous studies that focused only on the impact of ID in the brain. We also demonstrate that the ID diet reduced hematocrit levels compared to controls but not into the anemic range, and that animals on the ID diet exhibited RLS-like symptoms with regard to sleep onset and spinal cord reflex excitability. Interestingly, the effects on the spinal cord were stronger in females than in males, and the ID diet-induced behaviors were rescued by the return of the animals to the control diet. Taken together, these results demonstrate that diet-induced ID changes to CNS function are both inducible and reversible, and that they mimic the sleep and sensorimotor RLS symptoms experienced in the clinic. We therefore propose replacing the commonly used phrase "brain iron deficiency" (BID) hypothesis in the RLS research field with the term "iron deficiency in the central nervous system" (ID-CNS), to include possible effects of altered iron levels on spinal cord function.
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4
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Silvani A, Ghorayeb I, Manconi M, Li Y, Clemens S. Putative Animal Models of Restless Legs Syndrome: A Systematic Review and Evaluation of Their Face and Construct Validity. Neurotherapeutics 2023; 20:154-178. [PMID: 36536233 PMCID: PMC10119375 DOI: 10.1007/s13311-022-01334-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2022] [Indexed: 12/24/2022] Open
Abstract
Restless legs syndrome (RLS) is a sensorimotor disorder that severely affects sleep. It is characterized by an urge to move the legs, which is often accompanied by periodic limb movements during sleep. RLS has a high prevalence in the population and is usually a life-long condition. While its origins remain unclear, RLS is initially highly responsive to treatment with dopaminergic agonists that target D2-like receptors, in particular D2 and D3, but the long-term response is often unsatisfactory. Over the years, several putative animal models for RLS have been developed, mainly based on the epidemiological and neurochemical link with iron deficiency, treatment efficacy of D2-like dopaminergic agonists, or genome-wide association studies that identified risk factors in the patient population. Here, we present the first systematic review of putative animal models of RLS, provide information about their face and construct validity, and report their role in deciphering the underlying pathophysiological mechanisms that may cause or contribute to RLS. We propose that identifying the causal links between genetic risk factors, altered organ functions, and changes to molecular pathways in neural circuitry will eventually lead to more effective new treatment options that bypass the side effects of the currently used therapeutics in RLS, especially for long-term therapy.
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Affiliation(s)
- Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum - University of Bologna, Ravenna Campus, Ravenna, Italy
| | - Imad Ghorayeb
- Département de Neurophysiologie Clinique, Pôle Neurosciences Cliniques, CHU de Bordeaux, Bordeaux, France
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, Université de Bordeaux, Bordeaux, France
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, CNRS, Bordeaux, France
| | - Mauro Manconi
- Sleep Medicine Unit, Neurocenter of Southern Switzerland, EOC, Ospedale Civico, Lugano, Switzerland
- Department of Neurology, University Hospital, Inselspital, Bern, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland
| | - Yuqing Li
- Department of Neurology, College of Medicine, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
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5
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Machado PC, Brito LF, Martins R, Pinto LFB, Silva MR, Pedrosa VB. Genome-Wide Association Analysis Reveals Novel Loci Related with Visual Score Traits in Nellore Cattle Raised in Pasture-Based Systems. Animals (Basel) 2022; 12:ani12243526. [PMID: 36552446 PMCID: PMC9774243 DOI: 10.3390/ani12243526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/06/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022] Open
Abstract
Body conformation traits assessed based on visual scores are widely used in Zebu cattle breeding programs. The aim of this study was to identify genomic regions and biological pathways associated with body conformation (CONF), finishing precocity (PREC), and muscling (MUSC) in Nellore cattle. The measurements based on visual scores were collected in 20,807 animals raised in pasture-based systems in Brazil. In addition, 2775 animals were genotyped using a 35 K SNP chip, which contained 31,737 single nucleotide polymorphisms after quality control. Single-step GWAS was performed using the BLUPF90 software while candidate genes were identified based on the Ensembl Genes 69. PANTHER and REVIGO platforms were used to identify key biological pathways and STRING to create gene networks. Novel candidate genes were revealed associated with CONF, including ALDH9A1, RXRG, RAB2A, and CYP7A1, involved in lipid metabolism. The genes associated with PREC were ELOVL5, PID1, DNER, TRIP12, and PLCB4, which are related to the synthesis of long-chain fatty acids, lipid metabolism, and muscle differentiation. For MUSC, the most important genes associated with muscle development were SEMA6A, TIAM2, UNC5A, and UIMC1. The polymorphisms identified in this study can be incorporated in commercial genotyping panels to improve the accuracy of genomic evaluations for visual scores in beef cattle.
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Affiliation(s)
- Pamela C. Machado
- Department of Animal Sciences, State University of Ponta Grossa, Ponta Grossa 84030-900, PR, Brazil
| | - Luiz F. Brito
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Rafaela Martins
- Department of Animal Sciences, State University of Ponta Grossa, Ponta Grossa 84030-900, PR, Brazil
| | - Luis Fernando B. Pinto
- Department of Animal Science, Federal University of Bahia, Av. Adhemar de Barros 500, Ondina, Salvador 40170-110, BA, Brazil
| | - Marcio R. Silva
- Melhore Animal and Katayama Agropecuaria Lda, Guararapes 16700-000, SP, Brazil
| | - Victor B. Pedrosa
- Department of Animal Sciences, State University of Ponta Grossa, Ponta Grossa 84030-900, PR, Brazil
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA
- Correspondence:
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Lyu S, Xing H, Liu Y, Girdhar P, Yokoi F, Li Y. Further Studies on the Role of BTBD9 in the Cerebellum, Sleep-like Behaviors and the Restless Legs Syndrome. Neuroscience 2022; 505:78-90. [PMID: 36244636 PMCID: PMC10367443 DOI: 10.1016/j.neuroscience.2022.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/15/2022] [Accepted: 10/09/2022] [Indexed: 11/26/2022]
Abstract
Genetic analyses have linked BTBD9 to restless legs syndrome (RLS) and sleep regulation. Btbd9 knockout mice show RLS-like motor restlessness. Previously, we found hyperactivity of cerebellar Purkinje cells (PCs) in Btbd9 knockout mice, which may contribute to the motor restlessness observed. However, underlying mechanisms for PC hyperactivity in Btbd9 knockout mice are unknown. Here, we used dissociated PC recording, brain slice recording and western blot to address this question. Our dissociated recording shows that knockout PCs had increased TEA-sensitive, Ca2+-dependent K+ currents. Applying antagonist to large conductance Ca2+-activated K+ (BK) channels further isolated the increased current as BK current. Consistently, we found increased amplitude of afterhyperpolarization and elevated BK protein levels in the knockout mice. Dissociated recording also shows a decrease in TEA-insensitive, Ca2+-dependent K+ currents. The result is consistent with reduced amplitude of tail currents, mainly composed of small conductance Ca2+-activated K+ (SK) currents, in slice recording. Our results suggest that BK and SK channels may be responsible for the hyperactivity of knockout PCs. Recently, BTBD9 protein was shown to associate with SYNGAP1 protein. We found a decreased cerebellar level of SYNGAP1 in Btbd9 knockout mice. However, Syngap1 heterozygous knockout mice showed nocturnal, instead of diurnal, motor restlessness. Our results suggest that SYNGAP1 deficiency may not contribute directly to the RLS-like motor restlessness observed in Btbd9 knockout mice. Finally, we found that PC-specific Btbd9 knockout mice exhibited deficits in motor coordination and balance similar to Btbd9 knockout mice, suggesting that the motor effect of BTBD9 in PCs is cell-autonomous.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hong Xing
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Yuning Liu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Pallavi Girdhar
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Fumiaki Yokoi
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.
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7
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Jiang J, Chen M, Huang H, Chen Y. The Aetiology of Tourette Syndrome and Chronic Tic Disorder in Children and Adolescents: A Comprehensive Systematic Review of Case-Control Studies. Brain Sci 2022; 12:brainsci12091202. [PMID: 36138938 PMCID: PMC9496979 DOI: 10.3390/brainsci12091202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/28/2022] [Accepted: 08/31/2022] [Indexed: 12/02/2022] Open
Abstract
(1) Introduction: Tourette syndrome (TS) and chronic tic disorder (CTD) are common neurodevelopmental/-psychiatric disorders. The aetiological factors that contribute to the pathogenesis of TS/CTD are still poorly understood. The possible risk factors for TS/CTD are considered to be a combination of genetic, immunological, psychological and environmental factors. A comprehensive systematic review was conducted to assess the association between aetiological factors and TS/CTD. (2) Methods: Electronic databases, including PubMed, Embase, Web of Science, Wanfang data, and CNKI, were searched to identify the etiological factors of children and adolescents (≤18 years) with TS/CTD based on a case-control study. Quality assessments were performed according to the Newcastle-Ottawa scale (NOS). (3) Results: According to sample sizes and NOS values, recent evidence may support that genetic factors (BTBD9 and AADAC), immunological factors (streptococcus and mycoplasma pneumoniae infections), environmental factors (conflict, history of perinatal diseases, and family history of neurological and psychiatric diseases and recurrent respiratory infections) and psychological factors (major life events) are associated with the pathogenesis of TS/CTD. (4) Conclusions: Some risk factors in different categories may be the etiological factors of TS/CTD, but there is a lack of studies on the interaction among the factors, which may require more attention in the future.
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Salminen AV, Clemens S, García-Borreguero D, Ghorayeb I, Li Y, Manconi M, Ondo W, Rye D, Siegel JM, Silvani A, Winkelman JW, Allen RP, Ferré S. Consensus guidelines on the construct validity of rodent models of restless legs syndrome. Dis Model Mech 2022; 15:dmm049615. [PMID: 35946581 PMCID: PMC9393041 DOI: 10.1242/dmm.049615] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/10/2022] [Indexed: 12/16/2022] Open
Abstract
Our understanding of the causes and natural course of restless legs syndrome (RLS) is incomplete. The lack of objective diagnostic biomarkers remains a challenge for clinical research and for the development of valid animal models. As a task force of preclinical and clinical scientists, we have previously defined face validity parameters for rodent models of RLS. In this article, we establish new guidelines for the construct validity of RLS rodent models. To do so, we first determined and agreed on the risk, and triggering factors and pathophysiological mechanisms that influence RLS expressivity. We then selected 20 items considered to have sufficient support in the literature, which we grouped by sex and genetic factors, iron-related mechanisms, electrophysiological mechanisms, dopaminergic mechanisms, exposure to medications active in the central nervous system, and others. These factors and biological mechanisms were then translated into rodent bioequivalents deemed to be most appropriate for a rodent model of RLS. We also identified parameters by which to assess and quantify these bioequivalents. Investigating these factors, both individually and in combination, will help to identify their specific roles in the expression of rodent RLS-like phenotypes, which should provide significant translational implications for the diagnosis and treatment of RLS.
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Affiliation(s)
- Aaro V. Salminen
- Institute of Neurogenomics, Helmholtz Zentrum München GmbH - German Research Center for Environmental Health, 85764 Neuherberg, Germany
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | | | - Imad Ghorayeb
- Département de Neurophysiologie Clinique, Pôle Neurosciences Cliniques, CHU de Bordeaux, 33076 Bordeaux, France
- Université de Bordeaux, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, 33076 Bordeaux, France
- CNRS, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, 33076 Bordeaux, France
| | - Yuqing Li
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Mauro Manconi
- Sleep Medicine Unit, Regional Hospital of Lugano, Neurocenter of Southern Switzerland, 6900 Lugano, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, 6900 Lugano, Switzerland
- Department of Neurology, University Hospital Inselspital, 3010 Bern, Switzerland
| | - William Ondo
- Houston Methodist Hospital Neurological Institute, Weill Cornell Medical School, Houston, TX 77070, USA
| | - David Rye
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jerome M. Siegel
- Neuropsychiatric Institute and Brain Research Institute, University of California, Los Angeles, CA 90095, USA
- Neurobiology Research, Veterans Administration Greater Los Angeles Healthcare System, North Hills, CA 91343, USA
| | - Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences Alma Mater Studiorum, Università di Bologna, 48121 Ravenna Campus, Ravenna, Italy
| | - John W. Winkelman
- Departments of Psychiatry and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Richard P. Allen
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21224, USA
| | - Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
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9
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Khachatryan SG, Ferri R, Fulda S, Garcia‐Borreguero D, Manconi M, Muntean M, Stefani A. Restless legs syndrome: Over 50 years of European contribution. J Sleep Res 2022; 31:e13632. [PMID: 35808955 PMCID: PMC9542244 DOI: 10.1111/jsr.13632] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 11/28/2022]
Abstract
Restless legs syndrome (RLS) is a sensorimotor neurological disorder characterised by an urge to move the limbs with a circadian pattern (occurring in the evening/at night), more prominent at rest, and relieved with movements. RLS is one of the most prevalent sleep disorders, occurring in 5%-10% of the European population. Thomas Willis first described RLS clinical cases already in the 17th century, and Karl-Axel Ekbom described the disease as a modern clinical entity in the 20th century. Despite variable severity, RLS can markedly affect sleep (partly through the presence of periodic leg movements) and quality of life, with a relevant socio-economic impact. Thus, its recognition and treatment are essential. However, screening methods present limitations and should be improved. Moreover, available RLS treatment options albeit providing sustained relief to many patients are limited in number. Additionally, the development of augmentation with dopamine agonists represents a major treatment problem. A better understanding of RLS pathomechanisms can bring to light novel treatment possibilities. With emerging new avenues of research in pharmacology, imaging, genetics, and animal models of RLS, this is an interesting and constantly growing field of research. This review will update the reader on the current state of RLS clinical practice and research, with a special focus on the contribution of European researchers.
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Affiliation(s)
- Samson G. Khachatryan
- Department of Neurology and NeurosurgeryNational Institute of HealthYerevanArmenia
- Sleep Disorders CenterSomnus Neurology ClinicYerevanArmenia
| | | | - Stephany Fulda
- Sleep Medicine UnitNeurocenter of Southern Switzerland, Ospedale CivicoLuganoSwitzerland
| | | | - Mauro Manconi
- Sleep Medicine UnitNeurocenter of Southern Switzerland, Ospedale CivicoLuganoSwitzerland
- Department of NeurologyUniversity HospitalInselspitalBernSwitzerland
| | - Maria‐Lucia Muntean
- Center for Parkinson's Disease and Movement DisordersParacelsus‐Elena KlinikKasselGermany
| | - Ambra Stefani
- Sleep Disorders Clinic, Department of NeurologyMedical University of InnsbruckInnsbruckAustria
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10
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Gao Z, Wang A, Zhao Y, Zhang X, Yuan X, Li N, Xu C, Wang S, Zhu Y, Zhu J, Guan J, Liu F, Yin S. Integrative Proteome and Ubiquitinome Analyses Reveal the Substrates of BTBD9 and Its Underlying Mechanism in Sleep Regulation. ACS OMEGA 2022; 7:11839-11852. [PMID: 35449961 PMCID: PMC9016840 DOI: 10.1021/acsomega.1c07262] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Ubiquitination is a major posttranslational modification of proteins that affects their stability, and E3 ligases play a key role in ubiquitination by specifically recognizing their substrates. BTBD9, an adaptor of the Cullin-RING ligase complex, is responsible for substrate recognition and is associated with sleep homeostasis. However, the substrates of BTBD9-mediated ubiquitination remain unknown. Here, we generated an SH-SY5Y cell line stably expressing BTBD9 and performed proteomic analysis combined with ubiquitinome analysis to identify the downstream targets of BTBD9. Through this approach, we identified four potential BTBD9-mediated ubiquitination substrates that are targeted for degradation. Among these candidate substrates, inosine monophosphate dehydrogenase (IMPDH2), a novel target of BTBD9-mediated degradation, is a potential risk gene for sleep dysregulation. In conclusion, these findings not only demonstrate that proteomic analysis can be a useful general approach for the systematic identification of E3 ligase substrates but also identify novel substrates of BTBD9, providing a resource for future studies of sleep regulation mechanisms.
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Affiliation(s)
- Zhenfei Gao
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Anzhao Wang
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Yongxu Zhao
- CAS
Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai
Institute of Nutrition and Health, Shanghai Institutes for Biological
Sciences, University of Chinese Academy of Sciences, Chinese Academy
of Sciences, Shanghai 200231, China
| | - Xiaoxu Zhang
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Xiangshan Yuan
- Department
of Anatomy and Histoembryology, School of Basic Medical Sciences,
State Key Laboratory of Medical Neurobiology and MOE Frontiers Center
for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200231, China
| | - Niannian Li
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Chong Xu
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Shenming Wang
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Yaxin Zhu
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Jingyu Zhu
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Jian Guan
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Feng Liu
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
| | - Shankai Yin
- Department
of Otolaryngology Head and Neck Surgery & Center of Sleep Medicine, Otolaryngology Institute of Shanghai Jiao Tong University,
Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Yishan Road 600, Shanghai 200233, China
- Shanghai
Key Laboratory of Sleep Disordered Breathing, Yishan Road 600, Shanghai 200233, China
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11
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Abstract
Restless legs syndrome (RLS) is a common sensorimotor disorder characterized by an urge to move that appears during rest or is exacerbated by rest, that occurs in the evening or night and that disappears during movement or is improved by movement. Symptoms vary considerably in age at onset, frequency and severity, with severe forms affecting sleep, quality of life and mood. Patients with RLS often display periodic leg movements during sleep or resting wakefulness. RLS is considered to be a complex condition in which predisposing genetic factors, environmental factors and comorbidities contribute to the expression of the disorder. RLS occurs alone or with comorbidities, for example, iron deficiency and kidney disease, but also with cardiovascular diseases, diabetes mellitus and neurological, rheumatological and respiratory disorders. The pathophysiology is still unclear, with the involvement of brain iron deficiency, dysfunction in the dopaminergic and nociceptive systems and altered adenosine and glutamatergic pathways as hypotheses being investigated. RLS is poorly recognized by physicians and it is accordingly often incorrectly diagnosed and managed. Treatment guidelines recommend initiation of therapy with low doses of dopamine agonists or α2δ ligands in severe forms. Although dopaminergic treatment is initially highly effective, its long-term use can result in a serious worsening of symptoms known as augmentation. Other treatments include opioids and iron preparations.
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12
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Franco B, Mota DS, Daubian-Nosé P, Rodrigues NDA, Simino LADP, de Fante T, Bezerra RMN, Manchado Gobatto FDB, Manconi M, Torsoni AS, Esteves AM. Iron deficiency in pregnancy: Influence on sleep, behavior, and molecular markers of adult male offspring. J Neurosci Res 2021; 99:3325-3338. [PMID: 34651324 DOI: 10.1002/jnr.24968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 08/17/2021] [Accepted: 08/31/2021] [Indexed: 12/14/2022]
Abstract
Iron restriction during pregnancy can lead to iron deficiency and changes in the dopaminergic system in the adulthood of offspring, and restless legs syndrome (RLS) is closely related to these changes. Objectives: Analyze whether iron restriction during pregnancy would cause changes in the behavior, sleep, and dopaminergic system of the male offspring. In addition, we aimed to assess whether exercise would be able to modulate these variables. The pregnant rats (Wistar) were divided into four groups with different concentrations of iron in the diet: standard (St), supplementation (Su), restriction since weaning (R1), and restriction only during pregnancy (R2). After birth, the offspring were assigned to their respective groups according to the dams diet (St, Su, R1, and R2) and distributed into sedentary (SD) and exercised (EX) (for 8 weeks of training), reaching eight groups of offspring (O): OSt SD, OSt EX, OSu SD, OSu EX, OR1 SD, OR1 EX, OR2 SD, and OR2 EX. Sleep, behavior, and analysis of key genes of dopaminergic system (D2, DAT) were performed after 8 weeks. The results for trained offspring that the mother received supplementation diet were the most expressive, with increased freezing and the OR1 SD group showed an increase in DAT protein content. These changes may have been due to the association between the dams diet during pregnancy and the practice of exercise by the offspring. The different concentrations of iron during pregnancy caused changes in the offspring, however, they were not associated with fetal programming in the context of RLS.
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Affiliation(s)
- Beatriz Franco
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Campinas, Brazil
| | - Diego Silva Mota
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | - Paulo Daubian-Nosé
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | | | | | - Thaís de Fante
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | | | - Fúlvia de Barros Manchado Gobatto
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Campinas, Brazil.,Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital of Lugano (EOC), Lugano, Switzerland
| | | | - Andrea Maculano Esteves
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Campinas, Brazil.,Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
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13
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Ferré S, Guitart X, Quiroz C, Rea W, García-Malo C, Garcia-Borreguero D, Allen RP, Earley CJ. Akathisia and Restless Legs Syndrome: Solving the Dopaminergic Paradox. Sleep Med Clin 2021; 16:249-267. [PMID: 33985651 DOI: 10.1016/j.jsmc.2021.02.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Akathisia is an urgent need to move that is associated with treatment with dopamine receptor blocking agents (DRBAs) and with restless legs syndrome (RLS). The pathogenetic mechanism of akathisia has not been resolved. This article proposes that it involves an increased presynaptic dopaminergic transmission in the ventral striatum and concomitant strong activation of postsynaptic dopamine D1 receptors, which form complexes (heteromers) with dopamine D3 and adenosine A1 receptors. It also proposes that in DRBA-induced akathisia, increased dopamine release depends on inactivation of autoreceptors, whereas in RLS it depends on a brain iron deficiency-induced down-regulation of striatal presynaptic A1 receptors.
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Affiliation(s)
- Sergi Ferré
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Building, 333 Cassell Drive, Baltimore, MD 21224, USA.
| | - Xavier Guitart
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Building, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - César Quiroz
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Building, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - William Rea
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Building, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Celia García-Malo
- Sleep Research Institute, Paseo de la Habana 151, Madrid 28036, Spain
| | | | - Richard P Allen
- Department of Neurology, Johns Hopkins University, Johns Hopkins Bayview Medical Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
| | - Christopher J Earley
- Department of Neurology, Johns Hopkins University, Johns Hopkins Bayview Medical Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
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14
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Alteration of the cholinergic system and motor deficits in cholinergic neuron-specific Dyt1 knockout mice. Neurobiol Dis 2021; 154:105342. [PMID: 33757902 DOI: 10.1016/j.nbd.2021.105342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/11/2021] [Accepted: 03/18/2021] [Indexed: 12/30/2022] Open
Abstract
Dystonia is a neurological movement disorder characterized by sustained or intermittent muscle contractions, repetitive movement, and sometimes abnormal postures. DYT1 dystonia is one of the most common genetic dystonias, and most patients carry heterozygous DYT1 ∆GAG mutations causing a loss of a glutamic acid of the protein torsinA. Patients can be treated with anticholinergics, such as trihexyphenidyl, suggesting an abnormal cholinergic state. Early work on the cell-autonomous effects of Dyt1 deletion with ChI-specific Dyt1 conditional knockout mice (Dyt1 Ch1KO) revealed abnormal electrophysiological responses of striatal ChIs to muscarine and quinpirole, motor deficits, and no changes in the number or size of the ChIs. However, the Chat-cre line that was used to derive Dyt1 Ch1KO mice contained a neomycin cassette and was reported to have ectopic cre-mediated recombination. In this study, we generated a Dyt1 Ch2KO mouse line by removing the neomycin cassette in Dyt1 Ch1KO mice. The Dyt1 Ch2KO mice showed abnormal paw clenching behavior, motor coordination and balance deficits, impaired motor learning, reduced striatal choline acetyltransferase protein level, and a reduced number of striatal ChIs. Furthermore, the mutant striatal ChIs had a normal muscarinic inhibitory function, impaired quinpirole-mediated inhibition, and altered current density. Our findings demonstrate a cell-autonomous effect of Dyt1 deletion on the striatal ChIs and a critical role for the striatal ChIs and corticostriatal pathway in the pathogenesis of DYT1 dystonia.
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15
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Salminen AV, Silvani A, Allen RP, Clemens S, Garcia-Borreguero D, Ghorayeb I, Ferré S, Li Y, Ondo W, Picchietti DL, Rye D, Siegel JM, Winkelman JW, Manconi M. Consensus Guidelines on Rodent Models of Restless Legs Syndrome. Mov Disord 2021; 36:558-569. [PMID: 33382140 PMCID: PMC8313425 DOI: 10.1002/mds.28401] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/29/2020] [Accepted: 10/26/2020] [Indexed: 01/18/2023] Open
Abstract
Restless legs syndrome (RLS) is a chronic sensorimotor disorder diagnosed by clinical symptoms. It is challenging to translate the diagnostic self-reported features of RLS to animals. To help researchers design their experiments, a task force was convened to develop consensus guidelines for experimental readouts in RLS animal models. The RLS clinical diagnostic criteria were used as a starting point. After soliciting additional important clinical features of RLS, a consensus set of methods and outcome measures intent on capturing these features-in the absence of a face-to-face interview-was generated and subsequently prioritized by the task force. These were, in turn, translated into corresponding methods and outcome measures for research on laboratory rats and mice and used to generate the final recommendations. The task force recommended activity monitoring and polysomnography as principal tools in assessing RLS-like behavior in rodents. Data derived from these methods were determined to be the preferred surrogate measures for the urge to move, the principal defining feature of RLS. The same tools may be used to objectively demonstrate sleep-state features highly associated with RLS, such as sleep disturbance and number and periodicity of limb movements. Pharmacological challenges and dietary or other manipulations that affect iron availability are desirable to aggravate or improve RLS-like behavior and lend greater confidence that the animal model being proffered replicates key clinical features of RLS. These guidelines provide the first consensus experimental framework for researchers to use when developing new rodent models of RLS. © 2020 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Aaro V. Salminen
- Institute of Neurogenomics, Helmholtz Zentrum München GmbH - German Research Center for Environmental Health, Neuherberg, Germany,Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Richard P. Allen
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | | | - Imad Ghorayeb
- Département de Neurophysiologie Clinique, Pôle Neurosciences Cliniques, CHU de Bordeaux, Bordeaux, France,Université de Bordeaux, Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, UMR 5287, Bordeaux, France,CNRS, Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, UMR 5287, Bordeaux, France
| | - Sergi Ferré
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - William Ondo
- Houston Methodist Hospital Neurological Institute, Weill Cornell Medical School, Houston, Texas, USA
| | - Daniel L. Picchietti
- University of Illinois School of Medicine, Carle Illinois College of Medicine and Carle Foundation Hospital, Urbana, Illinois, USA
| | - David Rye
- Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jerome M. Siegel
- Neuropsychiatric Institute and Brain Research Institute, University of California, Los Angeles, Los Angeles, California, USA,Neurobiology Research, Veterans Administration Greater Los Angeles Healthcare System, North Hills, California, USA
| | - John W. Winkelman
- Departments of Psychiatry and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mauro Manconi
- Sleep Medicine Unit, Regional Hospital of Lugano, Neurocenter of Southern Switzerland, Lugano, Switzerland,Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland,Department of Neurology, University Hospital Inselspital, Bern, Switzerland,Correspondence to: Dr. Mauro Manconi, Sleep Medicine, Neurocenter of Southern Switzerland, Via Tesserete 46, Regional Hospital of Lugano, 6900 Lugano, Switzerland;
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16
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Lyu S, Xing H, Liu Y, Girdhar P, Zhang K, Yokoi F, Xiao R, Li Y. Deficiency of Meis1, a transcriptional regulator, in mice and worms: Neurochemical and behavioral characterizations with implications in the restless legs syndrome. J Neurochem 2020; 155:522-537. [PMID: 32910473 PMCID: PMC7894994 DOI: 10.1111/jnc.15177] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/04/2020] [Accepted: 08/28/2020] [Indexed: 12/21/2022]
Abstract
Restless legs syndrome is a sleep-related sensorimotor neurological disease affecting up to 10% of the population. Genetic analyses have identified Myeloid Ecotropic viral Integration Site 1 (MEIS1), a transcriptional regulator, to be associated with not only the restless legs syndrome but also self-reported symptoms of insomnia and sleep. This study is to determine if Meis1 deficiency in mice can lead to restless legs syndrome-like phenotypes, and if it is the case, what the underlying mechanisms are. We used two genetic model systems, Caenorhabditis elegans and mice. Egg retention assay and fluorescent reporters were used with C. elegans. For mice, we performed behavioral tests, serum and brain iron detection, qRT-PCR, western blot, immunohistochemistry, and in vitro brain-slice recording. Our results showed that with C. elegans, the function of dop-3, an orthologue of DRD2, was diminished after the knockdown of unc-62, an ortholog of MEIS1. Additionally, unc-62 knockdown led to enhanced transcription of the orthologue of tyrosine hydroxylase, cat-2. Meis1 knockout mice were hyperactive and had a rest-phase-specific increased probability of waking. Moreover, Meis1 knockout mice had increased serum ferritin and altered striatal dopaminergic and cholinergic systems. Specifically, Meis1 knockout mice showed an increased mRNA level but decreased protein level of tyrosine hydroxylase in the striatum. Furthermore, Meis1 knockout mice had increased striatal dopamine turnover and decreased spontaneous firing regularity of striatal cholinergic interneurons. Our data suggest that Meis1 knockout mice have restless legs syndrome-like motor restlessness and changes in serum ferritin levels. The symptoms may be related to dysfunctional dopaminergic and cholinergic systems.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Hong Xing
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Yuning Liu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Pallavi Girdhar
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Keer Zhang
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Fumiaki Yokoi
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Rui Xiao
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
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17
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Memon MD, Faiz S, Zaveri MP, Perry JC, Schuetz TM, Cancarevic I. Unraveling the Mysteries of Restless Leg Syndrome. Cureus 2020; 12:e10951. [PMID: 33083159 PMCID: PMC7567326 DOI: 10.7759/cureus.10951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Restless leg syndrome (RLS) or Willis-Ekbom disease (WED) is an under-diagnosed, chronic, and progressive primary sensory-motor disorder. It is characterized by an uncontrollable urge to move the legs due to uncomfortable and sometimes painful sensations, with a diurnal variation. RLS can lead to severe sleep disturbances, a usual cause of consultation. The pathophysiology is known partially, and it is believed that there is an association between the different variants of genetic mutations combined with dopaminergic and brain iron dysregulation, which plays an important role. The data used for this study were extracted from the articles found in the PubMed database that discuss different gene variants, pathophysiology, and various methods of treatment. They also highlight the role of iron in the pathogenesis of RLS as it is required for the synthesis of tyrosine hydroxylase, which is the rate-limiting step for dopamine synthesis. This review article provides a clinically useful overview of RLS in terms of pathophysiological findings, its genetic associations, and therapeutic options by using the currently available literature. Because RLS presents with vague symptoms and shares similarities with many other diseases, it might be overlooked by many physicians resulting in underdiagnosis and under-treatment. While these discoveries provide a breakthrough in understanding the details of RLS, further studies are recommended as these studies are limited to animal models and provide a limited representation of the general population.
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Affiliation(s)
- Mohammad D Memon
- Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Sadaf Faiz
- Research, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Mitul P Zaveri
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Jamal C Perry
- Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Tayná M Schuetz
- Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Ivan Cancarevic
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
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18
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Van Someren EJW. Brain mechanisms of insomnia: new perspectives on causes and consequences. Physiol Rev 2020; 101:995-1046. [PMID: 32790576 DOI: 10.1152/physrev.00046.2019] [Citation(s) in RCA: 169] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
While insomnia is the second most common mental disorder, progress in our understanding of underlying neurobiological mechanisms has been limited. The present review addresses the definition and prevalence of insomnia and explores its subjective and objective characteristics across the 24-hour day. Subsequently, the review extensively addresses how the vulnerability to develop insomnia is affected by genetic variants, early life stress, major life events, and brain structure and function. Further supported by the clear mental health risks conveyed by insomnia, the integrated findings suggest that the vulnerability to develop insomnia could rather be found in brain circuits regulating emotion and arousal than in circuits involved in circadian and homeostatic sleep regulation. Finally, a testable model is presented. The model proposes that in people with a vulnerability to develop insomnia, the locus coeruleus is more sensitive to-or receives more input from-the salience network and related circuits, even during rapid eye movement sleep, when it should normally be sound asleep. This vulnerability may ignite a downward spiral of insufficient overnight adaptation to distress, resulting in accumulating hyperarousal, which, in turn, impedes restful sleep and moreover increases the risk of other mental health adversity. Sensitized brain circuits are likely to be subjectively experienced as "sleeping with one eye open". The proposed model opens up the possibility for novel intervention studies and animal studies, thus accelerating the ignition of a neuroscience of insomnia, which is direly needed for better treatment.
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Affiliation(s)
- Eus J W Van Someren
- Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands; Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit University Amsterdam, Amsterdam, The Netherlands; and Amsterdam UMC, Vrije Universiteit, Psychiatry, Amsterdam Neuroscience, Amsterdam, The Netherlands
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19
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Lyu S, Doroodchi A, Xing H, Sheng Y, DeAndrade MP, Yang Y, Johnson TL, Clemens S, Yokoi F, Miller MA, Xiao R, Li Y. BTBD9 and dopaminergic dysfunction in the pathogenesis of restless legs syndrome. Brain Struct Funct 2020; 225:1743-1760. [PMID: 32468214 DOI: 10.1007/s00429-020-02090-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 05/13/2020] [Indexed: 01/17/2023]
Abstract
Restless legs syndrome (RLS) is characterized by an urge to move legs, usually accompanied by uncomfortable sensations. RLS symptoms generally happen at night and can be relieved by movements. Genetic studies have linked polymorphisms in BTBD9 to a higher risk of RLS. Knockout of BTBD9 homolog in mice (Btbd9) and fly results in RLS-like phenotypes. A dysfunctional dopaminergic system is associated with RLS. However, the function of BTBD9 in the dopaminergic system and RLS is not clear. Here, we made use of the simple Caenorhabditis elegans nervous system. Loss of hpo-9, the worm homolog of BTBD9, resulted in hyperactive egg-laying behavior. Analysis of genetic interactions between hpo-9 and genes for dopamine receptors (dop-1, dop-3) indicated that hpo-9 and dop-1 worked similarly. Reporter assays of dop-1 and dop-3 revealed that hpo-9 knockout led to a significant increase of DOP-3 expression. This appears to be evolutionarily conserved in mice with an increased D2 receptor (D2R) mRNA in the striatum of the Btbd9 knockout mice. Furthermore, the striatal D2R protein was significantly decreased and Dynamin I was increased. Overall, activities of DA neurons in the substantia nigra were not altered, but the peripheral D1R pathway was potentiated in the Btbd9 knockout mice. Finally, we generated and characterized the dopamine neuron-specific Btbd9 knockout mice and detected an active-phase sleepiness, suggesting that dopamine neuron-specific loss of Btbd9 is sufficient to disturb the sleep. Our results suggest that increased activities in the D1R pathway, decreased activities in the D2R pathway, or both may contribute to RLS.
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Affiliation(s)
- Shangru Lyu
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Atbin Doroodchi
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Hong Xing
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Yi Sheng
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Mark P DeAndrade
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Youfeng Yang
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Tracy L Johnson
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Fumiaki Yokoi
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Michael A Miller
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Rui Xiao
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Yuqing Li
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA.
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20
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Lyu S, Xing H, DeAndrade MP, Perez PD, Yokoi F, Febo M, Walters AS, Li Y. The Role of BTBD9 in the Cerebellum, Sleep-like Behaviors and the Restless Legs Syndrome. Neuroscience 2020; 440:85-96. [PMID: 32446853 DOI: 10.1016/j.neuroscience.2020.05.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 04/27/2020] [Accepted: 05/14/2020] [Indexed: 12/28/2022]
Abstract
Recent genome-wide association studies (GWAS) have found cerebellum as a top hit for sleep regulation. Restless legs syndrome (RLS) is a sleep-related sensorimotor disorder characterized by uncomfortable sensations in the extremities, generally at night, which are often relieved by movements. Clinical studies have found that RLS patients have structural and functional abnormalities in the cerebellum. However, whether and how cerebellar pathology contributes to sleep regulation and RLS is not known. GWAS identified polymorphisms in BTBD9 conferring a higher risk of sleep disruption and RLS. Knockout of the BTBD9 homolog in mice (Btbd9) and fly results in motor restlessness and sleep disruption. We performed manganese-enhanced magnetic resonance imaging on the Btbd9 knockout mice and found decreased neural activities in the cerebellum, especially in lobules VIII, X, and the deep cerebellar nuclei. Electrophysiological recording of Purkinje cells (PCs) from Btbd9 knockout mice revealed an increased number of non-tonic PCs. Tonic PCs showed increased spontaneous activity and intrinsic excitability. To further investigate the cerebellar contribution to RLS and sleep-like behaviors, we generated PC-specific Btbd9 knockout mice (Btbd9 pKO) and performed behavioral studies. Btbd9 pKO mice showed significant motor restlessness during the rest phase but not in the active phase. Btbd9 pKO mice also had an increased probability of waking at rest. Unlike the Btbd9 knockout mice, there was no increased thermal sensation in the Btbd9 pKO. Our results indicate that the Btbd9 knockout influences the PC activity; dysfunction in the cerebellum may contribute to the motor restlessness found in the Btbd9 knockout mice.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hong Xing
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Pablo D Perez
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Fumiaki Yokoi
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Marcelo Febo
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Arthur S Walters
- Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.
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21
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Lyu S, DeAndrade MP, Unger EL, Mueller S, Oksche A, Walters AS, Li Y. Mu opioid receptor knockout mouse: Phenotypes with implications on restless legs syndrome. J Neurosci Res 2020; 98:1532-1548. [PMID: 32424971 DOI: 10.1002/jnr.24637] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 04/12/2020] [Accepted: 04/17/2020] [Indexed: 12/19/2022]
Abstract
Restless legs syndrome (RLS) is characterized by an irresistible need to move the legs while sitting or lying at night with insomnia as a frequent consequence. Human RLS has been associated with abnormalities in the endogenous opioid system, the dopaminergic system, the iron regulatory system, anemia, and inflammatory and auto-immune disorders. Our previous work indicates that mice lacking all three subtypes of opioid receptors have a phenotype similar to that of human RLS. To study the roles of each opioid receptor subtype in RLS, we first used mu opioid receptor knockout (MOR KO) mice based on our earlier studies using postmortem brain and cell culture. The KO mice showed decreased hemoglobin, hematocrit, and red blood cells (RBCs), with an appearance of microcytic RBCs indicating anemia. Together with decreased serum iron and transferrin, but increased ferritin levels, the anemia is similar to that seen with chronic inflammation in humans. A decreased serum iron level was also observed in the wildtype mice treated with an MOR antagonist. Iron was increased in the liver and spleen of the KO mice. Normal circadian variations in the dopaminergic and serotoninergic systems were absent in the KO mice. The KO mice showed hyperactivity and increased thermal sensitivity in wakefulness primarily during what would normally be the sleep phase similar to that seen in human RLS. Deficits in endogenous opioid system transmission could predispose to anemia of inflammation and loss of circadian variations in dopaminergic or serotonergic systems, thereby contributing to an RLS-like phenotype.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Erica L Unger
- Department of Biology, Lebanon Valley College, Annville, PA, USA
| | | | - Alexander Oksche
- Mundipharma Research Limited, Cambridge, UK.,Rudolf-Buchheim-Institut für Pharmakologie, University of Giessen, Giessen, Germany
| | - Arthur S Walters
- Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
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22
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Abstract
Restless legs syndrome (RLS) is a neurological disorder characterized by an urge to move and uncomfortable sensations. Genetic studies have identified polymorphisms in up to 19 risk loci, including MEIS1 and BTBD9. Rodents deficient in either homolog show RLS-like phenotypes. However, whether MEIS1 and BTBD9 interact in vivo is unclear. Here, with C. elegans, we observed that the hyperactive egg-laying behavior caused by loss of BTBD9 homolog was counteracted by knockdown of MEIS1 homolog. This was further investigated in mutant mice with Btbd9, Meis1, or both knocked out. The double knockout mice showed an earlier onset of the motor deficit in the wheel running test but did not have increased sensitivity to the heat stimuli as observed in single KOs. Meis1 protein level was not influenced by Btbd9 deficiency, and Btbd9 transcription was not affected by Meis1 haploinsufficiency. Our results demonstrate that MEIS1 and BTBD9 do not regulate each other.
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Lyu S, Xing H, DeAndrade MP, Perez PD, Zhang K, Liu Y, Yokoi F, Febo M, Li Y. The role of BTBD9 in the cerebral cortex and the pathogenesis of restless legs syndrome. Exp Neurol 2019; 323:113111. [PMID: 31715135 DOI: 10.1016/j.expneurol.2019.113111] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/09/2019] [Accepted: 11/07/2019] [Indexed: 01/18/2023]
Abstract
Restless legs syndrome (RLS) is a nocturnal neurological disorder affecting up to 10% of the population. It is characterized by an urge to move and uncomfortable sensations in the legs which can be relieved by movements. Mutations in BTBD9 may confer a higher risk of RLS. We developed Btbd9 knockout mice as an animal model. Functional alterations in the cerebral cortex, especially the sensorimotor cortex, have been found in RLS patients in several imaging studies. However, the role of cerebral cortex in the pathogenesis of RLS remains unclear. To explore this, we used in vivo manganese-enhanced MRI and found that the Btbd9 knockout mice had significantly increased neural activities in the primary somatosensory cortex (S1) and the rostral piriform cortex. Morphometry study revealed a decreased thickness in a part of S1 representing the hindlimb (S1HL) and M1. The electrophysiological recording showed Btbd9 knockout mice had enhanced short-term plasticity at the corticostriatal terminals to D1 medium spiny neurons (MSNs). Furthermore, we specifically knocked out Btbd9 in the cerebral cortex of mice (Btbd9 cKO). The Btbd9 cKO mice showed a rest-phase specific motor restlessness, decreased thermal sensation, and a thinner S1HL and M1. Both Btbd9 knockout and Btbd9 cKO exhibited motor deficits. Our results indicate that systematic BTBD9 deficiency leads to both functional and morphometrical changes of the cerebral cortex, and an alteration in the corticostriatal pathway to D1 MSNs. Loss of BTBD9 only in the cerebral cortex is sufficient to cause similar phenotypes as observed in the Btbd9 complete knockout mice.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Hong Xing
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Pablo D Perez
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Keer Zhang
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Yuning Liu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Fumiaki Yokoi
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Marcelo Febo
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA.
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Muramatsu K, Chikahisa S, Shimizu N, Séi H, Inoue Y. Rotigotine suppresses sleep-related muscle activity augmented by injection of dialysis patients' sera in a mouse model of restless legs syndrome. Sci Rep 2019; 9:16344. [PMID: 31704978 PMCID: PMC6841937 DOI: 10.1038/s41598-019-52735-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 07/31/2019] [Indexed: 12/27/2022] Open
Abstract
Idiopathic restless legs syndrome (RLS) has a genetic basis wherein BTBD9 is associated with a higher risk of RLS. Hemodialysis patients also exhibit higher rates of RLS compared with the healthy population. However, little is known about the relationship of BTBD9 and end-stage renal disease to RLS pathophysiology. Here we evaluated sleep and leg muscle activity of Btbd9 mutant (MT) mice after administration of serum from patients with either idiopathic or RLS due to end-stage renal disease (renal RLS) and investigated the efficacy of treatment with the dopamine agonist rotigotine. At baseline, the amount of rapid eye movement (REM) sleep was decreased and leg muscle activity during non-REM (NREM) sleep was increased in MT mice compared to wild-type (WT) mice. Wake-promoting effects of rotigotine were attenuated by injection of serum from RLS patients in both WT and MT mice. Leg muscle activity during NREM sleep was increased only in MT mice injected with serum from RLS patients of ideiopatic and renal RLS. Subsequent treatment with rotigotine ameliorated this altered leg muscle activity. Together these results support previous reports showing a relationship between the Btbd9/dopamine system and RLS, and elucidate in part the pathophysiology of RLS.
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Affiliation(s)
- Kazuhiro Muramatsu
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan.,Department of Pediatrics, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Sachiko Chikahisa
- Department of Integrative Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Noriyuki Shimizu
- Department of Integrative Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Hiroyoshi Séi
- Department of Integrative Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Yuichi Inoue
- Department of Somnology, Tokyo Medical University, Tokyo, Japan.
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25
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The Role of BTBD9 in Striatum and Restless Legs Syndrome. eNeuro 2019; 6:ENEURO.0277-19.2019. [PMID: 31444227 PMCID: PMC6787346 DOI: 10.1523/eneuro.0277-19.2019] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 07/22/2019] [Accepted: 08/02/2019] [Indexed: 12/23/2022] Open
Abstract
Restless legs syndrome (RLS) is a sensory-motor neurological disorder characterized by uncomfortable sensations in the extremities, generally at night, which is often relieved by movements. Genome-wide association studies (GWAS) have identified mutations in BTBD9 conferring a higher risk of RLS. Knockout of the BTBD9 homolog in mice (Btbd9) and fly results in motor restlessness and sleep disruption. Clinical studies have found RLS patients have structural and functional abnormalities in the striatum; however, whether and how striatal pathology contributes to the pathogenesis of RLS is not known. Here, we used fMRI to map regions of altered synaptic activity in basal ganglia of systematic Btbd9 knock-out (KO) mice. We further dissected striatal circuits using patch-clamp electrophysiological recordings in brain slices. Two different mouse models were generated to test the effect of specific knockout of Btbd9 in either striatal medium spiny neurons (MSNs) or cholinergic interneurons (ChIs) using the electrophysiological recording, motor and sensory behavioral tests. We found that Btbd9 KO mice showed enhanced neural activity in the striatum, increased postsynaptic currents in the MSNs, and decreased excitability of the striatal ChIs. Knocking out Btbd9 specifically in the striatal MSNs, but not the ChIs, led to rest-phase specific motor restlessness, sleep disturbance, and increased thermal sensation in mice, which are consistent with results obtained from the Btbd9 KO mice. Our data establish the role of Btbd9 in regulating the activity of striatal neurons. Increased activity of the striatal MSNs, possibly through modulation by the striatal ChIs, contributes to the pathogenesis of RLS.
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26
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Hopfner F, Hobert MA, Maetzler C, Hansen C, Pham MH, Moreau C, Berg D, Devos D, Maetzler W. Mobility Deficits Assessed With Mobile Technology: What Can We Learn From Brain Iron-Altered Animal Models? Front Neurol 2019; 10:833. [PMID: 31440200 PMCID: PMC6694697 DOI: 10.3389/fneur.2019.00833] [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: 04/10/2019] [Accepted: 07/18/2019] [Indexed: 12/02/2022] Open
Abstract
Background: Recent developments in mobile technology have enabled the investigation of human movements and mobility under natural conditions, i.e., in the home environment. Iron accumulation in the basal ganglia is deleterious in Parkinson's disease (i.e., iron accumulation with lower striatal level of dopamine). The effect of iron chelation (i.e., re-deployment of iron) in Parkinson's disease patients is currently tested in a large investigator-initiated multicenter study. Conversely, restless legs syndrome (RLS) is associated with iron depletion and higher striatal level of dopamine. To determine from animal models which movement and mobility parameters might be associated with iron content modulation and the potential effect of therapeutic chelation inhuman. Methods: We recapitulated pathophysiological aspects of the association between iron, dopamine, and neuronal dysfunction and deterioration in the basal ganglia, and systematically searched PubMed to identify original articles reporting about quantitatively assessed mobility deficits in animal models of brain iron dyshomeostasis. Results: We found six original studies using murine and fly models fulfilling the inclusion criteria. Especially postural and trunk stability were altered in animal models with iron overload. Animal models with lowered basal ganglia iron suffered from alterations in physical activity, mobility, and sleep fragmentation. Conclusion: From preclinical investigations in the animal model, we can deduce that possibly also in humans with iron accumulation in the basal ganglia undergoing therapeutic chelation may primarily show changes in physical activity (such as daily “motor activity”), postural and trunk stability and sleep fragmentation. These changes can readily be monitored with currently available mobile technology.
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Affiliation(s)
- Franziska Hopfner
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany.,Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Markus A Hobert
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Corina Maetzler
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Clint Hansen
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Minh Hoang Pham
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Caroline Moreau
- Department of Movement Disorders and Neurology, Faculty of Medicine, Lille University Hospital, Lille University, INSERM U1171, Lille, France
| | - Daniela Berg
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - David Devos
- Departments of Medical Pharmacology and Movement Disorders, Lille University Hospital, Lille University, INSERM U1171, Lille, France
| | - Walter Maetzler
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
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27
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Lyu S, DeAndrade MP, Mueller S, Oksche A, Walters AS, Li Y. Hyperactivity, dopaminergic abnormalities, iron deficiency and anemia in an in vivo opioid receptors knockout mouse: Implications for the restless legs syndrome. Behav Brain Res 2019; 374:112123. [PMID: 31376441 DOI: 10.1016/j.bbr.2019.112123] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/24/2019] [Accepted: 07/30/2019] [Indexed: 12/13/2022]
Abstract
Previous studies have uncovered a potential role of the opioid system in iron hemostasis and dopamine metabolism. Abnormalities in both of these systems have been noted in human RLS. Autopsy studies of human RLS have shown an endogenous opioid deficiency in the thalamus. Opioids, particularly prolonged-release oxycodone/naloxone, have been approved in Europe to be a second-line therapy for severe restless legs syndrome (RLS). To study the role of opioid receptors in the pathogenesis of RLS, we used a triple knockout (KO) mouse strain that lack mu, delta, and kappa opioid receptors and explored the behavioral and biochemical parameters relevant to RLS. The triple KO mice showed hyperactivity and a trend of increased probability of waking during the rest period (day) akin to that in human RLS (night). Surprisingly, triple KO mice also exhibit decreased serum iron concentration, evidence of anemia, a significant dysfunction in dopamine metabolism akin to that noted in human RLS, as well as an increased latency in response to thermal stimuli. To our knowledge, this is the first study to demonstrate that the endogenous opioid system may play a role in iron metabolism and subsequently in the pathogenesis of anemia. It is also the first study showing that opioid receptors are involved in the production of motor restlessness with a circadian predominance. Our findings support the role of endogenous opioids in the pathogenesis of RLS, and the triple KO mice can be used to understand the relationship between iron deficiency, anemia, dopaminergic dysfunction, and RLS.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Stefan Mueller
- Mundipharma Research GmbH & Co. KG, Höhenstraße 10, Limburg, Germany
| | - Alexander Oksche
- Mundipharma Research Limited, Cambridge, UK; Rudolf-Buchheim-Institut für Pharmakologie, University of Giessen, Giessen, Germany
| | - Arthur S Walters
- Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.
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28
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29
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Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Agúndez JA. Neurochemical features of idiopathic restless legs syndrome. Sleep Med Rev 2019; 45:70-87. [DOI: 10.1016/j.smrv.2019.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 03/08/2019] [Accepted: 03/15/2019] [Indexed: 11/26/2022]
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30
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Chen P, Ijomone OM, Lee KH, Aschner M. Caenorhabditis elegans and its applicability to studies on restless legs syndrome. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2019; 84:147-174. [PMID: 31229169 DOI: 10.1016/bs.apha.2018.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Restless legs syndrome (RLS) is a common neurological disorder in the United States. This disorder is characterized by an irresistible urge to move the legs, although the symptoms vary in a wide range. The pathobiology of RLS has been linked to iron (Fe) deficiency and dopaminergic (DAergic) dysfunction. Several genetic factors have been reported to increase the risk of RLS. Caenorhabditis elegans (C. elegans) is a well-established animal model with a fully sequenced genome, which is highly conserved with mammals. Given the detailed knowledge of its genomic architecture, ease of genetic manipulation and conserved biosynthetic and metabolic pathways, as well as its small size, ease of maintenance, speedy generation time and large brood size, C. elegans provides numerous advantages in studying RLS-associated gene-environment interactions. Here we will review current knowledge about RLS symptoms, pathology and treatments, and discuss the application of C. elegans in RLS study, including the worm homologous genes and methods that could be performed to advance the pathophysiology RLS.
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Affiliation(s)
- Pan Chen
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Omamuyovwi Meashack Ijomone
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States; Department of Human Anatomy, Federal University of Technology, Akure, Nigeria
| | - Kun He Lee
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States.
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31
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Genome-wide analysis of insomnia in 1,331,010 individuals identifies new risk loci and functional pathways. Nat Genet 2019; 51:394-403. [PMID: 30804565 DOI: 10.1038/s41588-018-0333-3] [Citation(s) in RCA: 428] [Impact Index Per Article: 85.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 12/13/2018] [Indexed: 01/18/2023]
Abstract
Insomnia is the second most prevalent mental disorder, with no sufficient treatment available. Despite substantial heritability, insight into the associated genes and neurobiological pathways remains limited. Here, we use a large genetic association sample (n = 1,331,010) to detect novel loci and gain insight into the pathways, tissue and cell types involved in insomnia complaints. We identify 202 loci implicating 956 genes through positional, expression quantitative trait loci, and chromatin mapping. The meta-analysis explained 2.6% of the variance. We show gene set enrichments for the axonal part of neurons, cortical and subcortical tissues, and specific cell types, including striatal, hypothalamic, and claustrum neurons. We found considerable genetic correlations with psychiatric traits and sleep duration, and modest correlations with other sleep-related traits. Mendelian randomization identified the causal effects of insomnia on depression, diabetes, and cardiovascular disease, and the protective effects of educational attainment and intracranial volume. Our findings highlight key brain areas and cell types implicated in insomnia, and provide new treatment targets.
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32
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Uhl GR, Martinez MJ. PTPRD: neurobiology, genetics, and initial pharmacology of a pleiotropic contributor to brain phenotypes. Ann N Y Acad Sci 2019; 1451:112-129. [PMID: 30648269 PMCID: PMC6629525 DOI: 10.1111/nyas.14002] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 11/12/2018] [Accepted: 12/19/2018] [Indexed: 12/12/2022]
Abstract
Receptor-type protein tyrosine phosphatase, receptor type D (PTPRD) has likely roles as a neuronal cell adhesion molecule and synaptic specifier. Interest in its neurobiology and genomics has been stimulated by results from human genetics and mouse models for phenotypes related to addiction, restless leg syndrome, neurofibrillary pathology in Alzheimer's disease, cognitive impairment/intellectual disability, mood lability, and obsessive-compulsive disorder. We review PTPRD's discovery, gene family, candidate homomeric and heteromeric binding partners, phosphatase activities, brain distribution, human genetic associations with nervous system phenotypes, and mouse model data relevant to these phenotypes. We discuss the recently reported discovery of the first small molecule inhibitor of PTPRD phosphatase, the identification of its addiction-related effects, and the implications of these findings for the PTPRD-associated brain phenotypes. In assembling PTPRD neurobiology, human genetics, and mouse genetic and pharmacological datasets, we provide a compelling picture of the roles played by PTPRD, its variation, and its potential as a target for novel therapeutics.
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Affiliation(s)
- George R Uhl
- Neurology and Research Services, New Mexico VA Healthcare System, Albuquerque, New Mexico.,Departments of Neurology, Neuroscience, Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, New Mexico.,Biomedical Research Institute of New Mexico, Albuquerque, New Mexico.,Departments of Neurology, Neuroscience and Mental Health, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Maria J Martinez
- Neurology and Research Services, New Mexico VA Healthcare System, Albuquerque, New Mexico.,Biomedical Research Institute of New Mexico, Albuquerque, New Mexico
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33
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Lo Martire V, Alvente S, Bastianini S, Berteotti C, Valli A, Manconi M, Zoccoli G, Silvani A. Sleep and Tibialis Anterior Muscle Activity in Mice With Mild Hypoxia and Iron Deficiency: Implications for the Restless Legs Syndrome. Front Physiol 2018; 9:1818. [PMID: 30618828 PMCID: PMC6304696 DOI: 10.3389/fphys.2018.01818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/05/2018] [Indexed: 12/14/2022] Open
Abstract
Restless legs syndrome (RLS) is a neurological disorder that entails an urge to move with a circadian pattern during the evening/night. RLS may be accompanied by decreased sleep time and increased occurrence of periodic leg movements during sleep (PLMS), which involve bursts of tibialis anterior (TA) muscle electromyogram (EMG). Mild hypoxia and non-anemic iron deficiency, a highly prevalent nutritional deficiency, are relatively unexplored factors in RLS pathophysiology. We tested whether mice exposed to mild hypoxia, alone or in combination with non-anemic iron deficiency, show decreased sleep time particularly in the light (rest) period and increased occurrence of TA EMG phasic events similar to human PLMS. Female C57BL/6J mice were fed diets with low or normal iron for 6 months from weaning and instrumented with electrodes to record the electroencephalogram and the EMG of both TA muscles. Mice were recorded in a whole-body plethysmograph while breathing a normoxic or mildly hypoxic (15% O2) gas mixture for 48 h. Hypoxia increased minute ventilation during sleep. The low-iron diet decreased liver and serum iron, leaving blood hemoglobin and brainstem iron levels unaffected. Hypoxia, either alone or in combination with non-anemic iron deficiency, decreased non-rapid-eye-movement (non-REM) sleep time, but this occurred irrespective of the light/dark period and was not associated with increased occurrence of TA EMG events during non-REM sleep. These results do not support the hypothesis that mild hypoxia is sufficient to cause signs of RLS, either alone or in combination with non-anemic iron deficiency, pointing to the necessity of further susceptibility factors.
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Affiliation(s)
- Viviana Lo Martire
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Sara Alvente
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Stefano Bastianini
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Chiara Berteotti
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Alice Valli
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital (EOC) of Lugano, Lugano, Switzerland.,Department of Neurology, Bern University Hospital, Bern, Switzerland
| | - Giovanna Zoccoli
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Alessandro Silvani
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
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Zhang L, Fu YH. The molecular genetics of human sleep. Eur J Neurosci 2018; 51:422-428. [PMID: 30144347 DOI: 10.1111/ejn.14132] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 01/01/2023]
Abstract
It has been known for many years that genetic influences account for some of the individual differences in human sleep parameters, but the underlying molecular mechanisms remain unclear. With major advances of molecular biology and the recognition of heritable sleep behaviors in humans over the past 30 years, a number of genetic variants have been identified to be associated with human sleep timing, duration and quality, both in healthy individuals and under pathological conditions. Some of these variants were further validated and characterized in animal models, shedding light on the mechanism of how these variants likely alter sleep in humans, which may provide new insights into developing more effective treatments to improve human sleep.
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Affiliation(s)
- Luoying Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology and Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ying-Hui Fu
- Department of Neurology, University of California, San Francisco, California
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35
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Ferré S, García-Borreguero D, Allen RP, Earley CJ. New Insights into the Neurobiology of Restless Legs Syndrome. Neuroscientist 2018; 25:113-125. [PMID: 30047288 DOI: 10.1177/1073858418791763] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Restless legs syndrome (RLS) is a common sensorimotor disorder, whose basic components include a sensory experience, akathisia, and a sleep-related motor sign, periodic leg movements during sleep (PLMS), both associated with an enhancement of the individual's arousal state. The present review attempts to integrate the major clinical and experimental neurobiological findings into a heuristic pathogenetic model. The model also integrates the recent findings on RLS genetics indicating that RLS has aspects of a genetically moderated neurodevelopmental disorder involving mainly the cortico-striatal-thalamic-cortical circuits. Brain iron deficiency (BID) remains the key initial pathobiological factor and relates to alterations of iron acquisition by the brain, also moderated by genetic factors. Experimental evidence indicates that BID leads to a hyperdopaminergic and hyperglutamatergic states that determine the dysfunction of cortico-striatal-thalamic-cortical circuits in genetically vulnerable individuals. However, the enhanced arousal mechanisms critical to RLS are better explained by functional changes of the ascending arousal systems. Recent experimental and clinical studies suggest that a BID-induced hypoadenosinergic state provides the link for a putative unified pathophysiological mechanism for sensorimotor signs of RLS and the enhanced arousal state.
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Affiliation(s)
- Sergi Ferré
- 1 National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | | | - Richard P Allen
- 3 Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
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Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Agúndez JA. Genetics of restless legs syndrome: An update. Sleep Med Rev 2018; 39:108-121. [DOI: 10.1016/j.smrv.2017.08.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 10/19/2022]
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37
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Hermesdorf M, Sundermann B, Rawal R, Szentkirályi A, Dannlowski U, Berger K. Lack of Association Between Shape and Volume of Subcortical Brain Structures and Restless Legs Syndrome. Front Neurol 2018; 9:355. [PMID: 29867753 PMCID: PMC5968110 DOI: 10.3389/fneur.2018.00355] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/01/2018] [Indexed: 11/24/2022] Open
Abstract
Objective Previous studies on patients with restless legs syndrome (RLS) yielded inconclusive results in the magnetic resonance imaging (MRI)-based analyses of alterations of subcortical structures in the brain. The aim of this study was to compare volumes as well as shapes of subcortical structures and the hippocampus between RLS cases and controls. Additionally, the associations between the genetic risks for RLS and subcortical volumes were investigated. Methods We compared volumetric as well as shape differences assessed by 3 T MRI in the caudate nucleus, hippocampus, globus pallidus, putamen, and thalamus in 39 RLS cases versus 117 controls, nested within a population-based sample. In a subsample, we explored associations between known genetic risk markers for RLS and the volumes of the subcortical structures and the hippocampus. Results No significant differences between RLS cases and controls in subcortical and hippocampal shapes and volumes were observed. Furthermore, the genetic risk for RLS was unrelated to any alterations of subcortical and hippocampal gray matter volume. Interpretation We conclude that neither RLS nor the genetic risk for the disease give rise to changes in hippocampal and subcortical shapes and gray matter volumes.
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Affiliation(s)
- Marco Hermesdorf
- Institute of Epidemiology and Social Medicine, University of Münster, Münster, Germany
| | - Benedikt Sundermann
- Department of Clinical Radiology, University Hospital Münster, Münster, Germany
| | - Rajesh Rawal
- Institute of Epidemiology and Social Medicine, University of Münster, Münster, Germany
| | - András Szentkirályi
- Institute of Epidemiology and Social Medicine, University of Münster, Münster, Germany
| | - Udo Dannlowski
- Department of Psychiatry, University of Münster, Münster, Germany
| | - Klaus Berger
- Institute of Epidemiology and Social Medicine, University of Münster, Münster, Germany
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38
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Schnytzer Y, Simon-Blecher N, Li J, Waldman Ben-Asher H, Salmon-Divon M, Achituv Y, Hughes ME, Levy O. Tidal and diel orchestration of behaviour and gene expression in an intertidal mollusc. Sci Rep 2018; 8:4917. [PMID: 29559663 PMCID: PMC5861051 DOI: 10.1038/s41598-018-23167-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 03/07/2018] [Indexed: 12/17/2022] Open
Abstract
Intertidal inhabitants are exposed to the 24-hour solar day, and the 12.4 hour rising and falling of the tides. One or both of these cycles govern intertidal organisms' behaviour and physiology, yet little is known about the molecular clockworks of tidal rhythmicity. Here, we show that the limpet Cellana rota exhibits robust tidally rhythmic behaviour and gene expression. We assembled a de-novo transcriptome, identifying novel tidal, along with known circadian clock genes. Surprisingly, most of the putative circadian clock genes, lack a typical rhythmicity. We identified numerous tidally rhythmic genes and pathways commonly associated with the circadian clock. We show that not only is the behaviour of an intertidal organism in tune with the tides, but so too are many of its genes and pathways. These findings highlight the plasticity of biological timekeeping in nature, strengthening the growing notion that the role of 'canonical' circadian clock genes may be more fluid than previously thought, as exhibited in an organism which has evolved in an environment where tidal oscillations are the dominant driving force.
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Affiliation(s)
- Y Schnytzer
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, USA.
| | - N Simon-Blecher
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - J Li
- Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - H Waldman Ben-Asher
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - M Salmon-Divon
- Department of Molecular Biology, Ariel University, Ariel, Israel
| | - Y Achituv
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - M E Hughes
- Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - O Levy
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
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39
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Li G, Tang H, Wang C, Qi X, Chen J, Chen S, Ma J. Association of BTBD9 and MAP2K5/SKOR1 With Restless Legs Syndrome in Chinese Population. Sleep 2017; 40:3045871. [PMID: 28329290 DOI: 10.1093/sleep/zsx028] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Study Objectives The aim of the study was to investigate the relationship between genetic factors and primary restless legs syndrome (RLS) in Chinese population. Methods A total of 116 RLS patients and 200 controls were recruited and the diagnosis of RLS was based on the criteria of International RLS Study Group. Polymer chain reaction (PCR) and sequencing were used to detect 19 single nucleotide polymorphisms (SNPs) in six genetic loci (MEIS1, BTBD9, PTPRD, MAP2K5/SKOR1, TOX3, and Intergenic region of 2p14). Results Our study found that one SNP increased the risk of RLS in Chinese population: rs6494696 of MAP2K5/SKOR1 (odds ratio [OR] = 0.09, p < .0001, recessive model). A further meta-analysis of RLS in Asian population found that two SNPs of BTBD9 increased the risk of RLS: rs9296249 of BTBD9 (OR = 1.44, p = .000, T allele), rs9357271 of BTBD9 (OR = 1.38, p = .021, dominant model). Conclusion Our results confirmed the association of BTBD9 and MAP2K5/SKOR1 with primary RLS in Chinese population.
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Affiliation(s)
- Gen Li
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Huidong Tang
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Cheng Wang
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xuemei Qi
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jie Chen
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Shengdi Chen
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jianfang Ma
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
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40
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Salminen AV, Schormair B, Flachskamm C, Torres M, Müller-Myhsok B, Kimura M, Winkelmann J. Sleep disturbance by pramipexole is modified by Meis1 in mice. J Sleep Res 2017; 27:e12557. [DOI: 10.1111/jsr.12557] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/07/2017] [Indexed: 10/19/2022]
Affiliation(s)
- Aaro V. Salminen
- Institute of Neurogenomics; Helmholtz Zentrum München; Munich Germany
| | - Barbara Schormair
- Institute of Neurogenomics; Helmholtz Zentrum München; Munich Germany
| | | | - Miguel Torres
- Department of Cardiovascular Development and Repair; Centro Nacional de Investigaciones Cardiovasculares (CNIC); Madrid Spain
| | - Bertram Müller-Myhsok
- Max Planck Institute of Psychiatry; Munich Germany
- Institute of Translational Medicine; University of Liverpool; Liverpool UK
- Munich Cluster for Systems Neurology (SyNergy); Munich Germany
| | | | - Juliane Winkelmann
- Institute of Neurogenomics; Helmholtz Zentrum München; Munich Germany
- Munich Cluster for Systems Neurology (SyNergy); Munich Germany
- Institute of Human Genetics; Klinikum Rechts der Isar; Technische Universität München; Munich Germany
- Neurologic Clinic; Klinikum rechts der Isar; Technische Universität München; Munich Germany
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41
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Salminen AV, Garrett L, Schormair B, Rozman J, Giesert F, Niedermeier KM, Becker L, Rathkolb B, Rácz I, Klingenspor M, Klopstock T, Wolf E, Zimmer A, Gailus-Durner V, Torres M, Fuchs H, Hrabě de Angelis M, Wurst W, Hölter SM, Winkelmann J. Meis1: effects on motor phenotypes and the sensorimotor system in mice. Dis Model Mech 2017. [PMID: 28645892 PMCID: PMC5560065 DOI: 10.1242/dmm.030080] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
MEIS1 encodes a developmental transcription factor and has been linked to restless legs syndrome (RLS) in genome-wide association studies. RLS is a movement disorder leading to severe sleep reduction and has a substantial impact on the quality of life of patients. In genome-wide association studies, MEIS1 has consistently been the gene with the highest effect size and functional studies suggest a disease-relevant downregulation. Therefore, haploinsufficiency of Meis1 could be the system with the most potential for modeling RLS in animals. We used heterozygous Meis1-knockout mice to study the effects of Meis1 haploinsufficiency on mouse behavioral and neurological phenotypes, and to relate the findings to human RLS. We exposed the Meis1-deficient mice to assays of motor, sensorimotor and cognitive ability, and assessed the effect of a dopaminergic receptor 2/3 agonist commonly used in the treatment of RLS. The mutant mice showed a pattern of circadian hyperactivity, which is compatible with human RLS. Moreover, we discovered a replicable prepulse inhibition (PPI) deficit in the Meis1-deficient animals. In addition, these mice were hyposensitive to the PPI-reducing effect of the dopaminergic receptor agonist, highlighting a role of Meis1 in the dopaminergic system. Other reported phenotypes include enhanced social recognition at an older age that was not related to alterations in adult olfactory bulb neurogenesis previously shown to be implicated in this behavior. In conclusion, the Meis1-deficient mice fulfill some of the hallmarks of an RLS animal model, and revealed the role of Meis1 in sensorimotor gating and in the dopaminergic systems modulating it. Summary: Loss of Meis1 results in motor restlessness in mice, a phenotype resembling human restless legs syndrome, as well as altered sensorimotor gating and improved social discrimination memory.
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Affiliation(s)
- Aaro V Salminen
- Institute of Neurogenomics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Lillian Garrett
- Institute of Developmental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.,German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Barbara Schormair
- Institute of Neurogenomics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Jan Rozman
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.,German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Florian Giesert
- Institute of Developmental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Kristina M Niedermeier
- Institute of Developmental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Lore Becker
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Birgit Rathkolb
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.,German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.,Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-University München, 81377 Munich, Germany
| | - Ildikó Rácz
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.,Institute of Molecular Psychiatry, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | | | - Martin Klingenspor
- Chair of Molecular Nutritional Medicine, Technical University Munich, EKFZ - Else Kröner Fresenius Center for Nutritional Medicine, Gregor-Mendel-Str. 2, 85350 Freising-Weihenstephan, Germany
| | - Thomas Klopstock
- Department of Neurology, Friedrich-Baur-Institute, Klinikum der Ludwig-Maximilians-Universität München, Ziemssenstr. 1a, 80336 Munich, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen e. V. (DZNE), 81377 Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Adolf-Butenandt-Institut, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Eckhard Wolf
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-University München, 81377 Munich, Germany
| | - Andreas Zimmer
- Institute of Molecular Psychiatry, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Valérie Gailus-Durner
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Miguel Torres
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Helmut Fuchs
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Martin Hrabě de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.,German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.,Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität 85354 Freising, Germany
| | - Wolfgang Wurst
- Institute of Developmental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen e. V. (DZNE), 81377 Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Adolf-Butenandt-Institut, Ludwig-Maximilians-Universität München, 81377 Munich, Germany.,Chair of Developmental Genetics, Faculty of Life and Food Sciences Weihenstephan, Technische Universität München, 85354 Freising, Germany
| | - Sabine M Hölter
- Institute of Developmental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.,German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Zentrum München, 85764 Neuherberg, Germany .,Munich Cluster for Systems Neurology (SyNergy), Adolf-Butenandt-Institut, Ludwig-Maximilians-Universität München, 81377 Munich, Germany.,Institute of Human Genetics, Klinikum Rechts der Isar, Technische Universität München, 81675 Munich, Germany.,Neurologic Clinic, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany
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Winkelmann J, Schormair B, Xiong L, Dion PA, Rye DB, Rouleau GA. Genetics of restless legs syndrome. Sleep Med 2017; 31:18-22. [DOI: 10.1016/j.sleep.2016.10.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/19/2016] [Accepted: 10/22/2016] [Indexed: 11/25/2022]
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Khan FH, Ahlberg CD, Chow CA, Shah DR, Koo BB. Iron, dopamine, genetics, and hormones in the pathophysiology of restless legs syndrome. J Neurol 2017; 264:1634-1641. [PMID: 28236139 DOI: 10.1007/s00415-017-8431-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/16/2017] [Accepted: 02/18/2017] [Indexed: 12/16/2022]
Abstract
Restless legs syndrome (RLS) is a common, chronic neurologic condition, which causes a persistent urge to move the legs in the evening that interferes with sleep. Human and animal studies have been used to study the pathophysiologic state of RLS and much has been learned about the iron and dopamine systems in relation to RLS. Human neuropathologic and imaging studies have consistently shown decreased iron in different brain regions including substantia nigra and thalamus. These same areas also demonstrate a state of relative dopamine excess. While it is not known how these changes in dopamine or iron produce the symptoms of RLS, genetic and hormone studies of RLS have identified other biologic systems or genes, such as the endogenous opioid and melanocortin systems and BTBD9 and MEIS1, that may explain some of the iron or dopamine changes in relation to RLS. This manuscript will review what is known about the pathophysiology of RLS, especially as it relates to changes in iron, dopamine, genetics, and hormonal systems.
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Affiliation(s)
- Farhan H Khan
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Caitlyn D Ahlberg
- Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Christopher A Chow
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Divya R Shah
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Brian B Koo
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA.
- Connecticut Veterans Affairs Medical Center, 950 Campbell Avenue, West Haven, CT, 06516, USA.
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44
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Lucariello M, Vidal E, Vidal S, Saez M, Roa L, Huertas D, Pineda M, Dalfó E, Dopazo J, Jurado P, Armstrong J, Esteller M. Whole exome sequencing of Rett syndrome-like patients reveals the mutational diversity of the clinical phenotype. Hum Genet 2016; 135:1343-1354. [PMID: 27541642 PMCID: PMC5065581 DOI: 10.1007/s00439-016-1721-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 07/31/2016] [Indexed: 12/15/2022]
Abstract
Classical Rett syndrome (RTT) is a neurodevelopmental disorder where most of cases carry MECP2 mutations. Atypical RTT variants involve mutations in CDKL5 and FOXG1. However, a subset of RTT patients remains that do not carry any mutation in the described genes. Whole exome sequencing was carried out in a cohort of 21 female probands with clinical features overlapping with those of RTT, but without mutations in the customarily studied genes. Candidates were functionally validated by assessing the appearance of a neurological phenotype in Caenorhabditis elegans upon disruption of the corresponding ortholog gene. We detected pathogenic variants that accounted for the RTT-like phenotype in 14 (66.6 %) patients. Five patients were carriers of mutations in genes already known to be associated with other syndromic neurodevelopmental disorders. We determined that the other patients harbored mutations in genes that have not previously been linked to RTT or other neurodevelopmental syndromes, such as the ankyrin repeat containing protein ANKRD31 or the neuronal acetylcholine receptor subunit alpha-5 (CHRNA5). Furthermore, worm assays demonstrated that mutations in the studied candidate genes caused locomotion defects. Our findings indicate that mutations in a variety of genes contribute to the development of RTT-like phenotypes.
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Affiliation(s)
- Mario Lucariello
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet, 08908, Barcelona, Catalonia, Spain
| | - Enrique Vidal
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet, 08908, Barcelona, Catalonia, Spain
| | - Silvia Vidal
- Servei de Medicina Genètica i Molecular, Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Esplugues De Llobregat, Catalonia, Spain
| | - Mauricio Saez
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet, 08908, Barcelona, Catalonia, Spain
| | - Laura Roa
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet, 08908, Barcelona, Catalonia, Spain
| | - Dori Huertas
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet, 08908, Barcelona, Catalonia, Spain
| | - Mercè Pineda
- Fundació Hospital Sant Joan de Déu (HSJD), Barcelona, Catalonia, Spain
| | - Esther Dalfó
- Genetics Department, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Joaquin Dopazo
- Computational Genomics Department, Centro de Investigación Príncipe Felipe (CIPF), 46012, Valencia, Spain
- Bioinformatics of Rare Diseases (BIER), CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
- Functional Genomics Node (INB) at CIPF, 46012, Valencia, Spain
| | - Paola Jurado
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet, 08908, Barcelona, Catalonia, Spain.
| | - Judith Armstrong
- Servei de Medicina Genètica i Molecular, Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Esplugues De Llobregat, Catalonia, Spain.
- CIBER Enfermedades Raras, Barcelona, Catalonia, Spain.
- Department of Neurology, Hospital Sant Joan de Déu (HSJD), Barcelona, Catalonia, Spain.
| | - Manel Esteller
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet, 08908, Barcelona, Catalonia, Spain.
- Department of Physiological Sciences, School of Medicine and Health Sciences, University of Barcelona, Barcelona, Catalonia, Spain.
- Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain.
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45
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Connor JR, Patton SM, Oexle K, Allen RP. Iron and restless legs syndrome: treatment, genetics and pathophysiology. Sleep Med 2016; 31:61-70. [PMID: 28057495 DOI: 10.1016/j.sleep.2016.07.028] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 07/22/2016] [Accepted: 07/29/2016] [Indexed: 12/13/2022]
Abstract
In this article, we review the original findings from MRI and autopsy studies that demonstrated brain iron status is insufficient in individuals with restless legs syndrome (RLS). The concept of deficient brain iron status is supported by proteomic studies from cerebrospinal fluid (CSF) and from the clinical findings where intervention with iron, either dietary or intravenous, can improve RLS symptoms. Therefore, we include a section on peripheral iron status and how peripheral status may influence both the RLS symptoms and treatment strategy. Given the impact of iron in RLS, we have evaluated genetic data to determine if genes are directly involved in iron regulatory pathways. The result was negative. In fact, even the HFE mutation C282Y could not be shown to have a protective effect. Lastly, a consistent finding in conditions of low iron is increased expression of proteins in the hypoxia pathway. Although there is lack of clinical data that RLS patients are hypoxic, there are intriguing observations that environmental hypoxic conditions worsen RLS symptoms; in this chapter we review very compelling data for activation of hypoxic pathways in the brain in RLS patients. In general, the data in RLS point to a pathophysiology that involves decreased acquisition of iron by cells in the brain. Whether the decreased ability is genetically driven, activation of pathways (eg, hypoxia) that are designed to limit cellular uptake is unknown at this time; however, the data strongly support a functional rather than structural defect in RLS, suggesting that an effective treatment is possible.
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Affiliation(s)
- James R Connor
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, PA, USA.
| | - Stephanie M Patton
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, PA, USA
| | - Konrad Oexle
- Institut für Humangenetik, Technische Universität, Munich, Germany
| | - Richard P Allen
- The Johns Hopkins University, Dep of neuroloy, Baltimore, MD USA
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Abstract
Restless legs syndrome (RLS) is a complex disorder that involves sensory and motor systems. The major pathophysiology of RLS is low iron concentration in the substantia nigra containing the cell bodies of dopamine neurons that project to the striatum, an area that is crucial for modulating movement. People who have RLS often present with normal iron values outside the brain; recent studies implicate several genes are involved in the syndrome. Like most complex diseases, animal models usually do not faithfully capture the full phenotypic spectrum of "disease," which is a uniquely human construct. Nonetheless, animal models have proven useful in helping to unravel the complex pathophysiology of diseases such as RLS and suggesting novel treatment paradigms. For example, hypothesis-independent genome-wide association studies (GWAS) have identified several genes as increasing the risk for RLS, including BTBD9. Independently, the murine homolog Btbd9 was identified as a candidate gene for iron regulation in the midbrain in mice. The relevance of the phenotype of another of the GWAS identified genes, MEIS1, has also been explored. The role of Btbd9 in iron regulation and RLS-like behaviors has been further evaluated in mice carrying a null mutation of the gene and in fruit flies when the BTBD9 protein is degraded. The BTBD9 and MEIS1 stories originate from human GWAS research, supported by work in a genetic reference population of mice (forward genetics) and further verified in mice, fish flies, and worms. Finally, the role of genetics is further supported by an inbred mouse strain that displays many of the phenotypic characteristics of RLS. The role of animal models of RLS phenotypes is also extended to include periodic limb movements.
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Gan-Or Z, Zhou S, Johnson A, Montplaisir JY, Allen RP, Earley CJ, Desautels A, Dion PA, Xiong L, Rouleau GA. Case-Control and Family-Based Association Study of Specific PTPRD
Variants in Restless Legs Syndrome. Mov Disord Clin Pract 2016; 3:460-464. [DOI: 10.1002/mdc3.12306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 11/03/2015] [Accepted: 11/06/2015] [Indexed: 11/12/2022] Open
Affiliation(s)
- Ziv Gan-Or
- Montreal Neurological Institute and McGill University; Montréal Québec Canada
- Department of Human Genetics; McGill University; Montréal Québec Canada
| | - Sirui Zhou
- Département de Médicine; Université de Montréal; Montréal Québec Canada
| | - Amelie Johnson
- Département de Médicine; Université de Montréal; Montréal Québec Canada
- Laboratoire de Neurogénétique; Centre de Recherche; Institut Universitaire en Santé Mentale de Montréal; Montréal Québec Canada
| | - Jacques Y. Montplaisir
- Centre d'Études Avancées en Médecine du Sommeil; Hôpital du Sacré-Cœur de Montréal; Montréal Québec Canada
- Département de Psychiatrie; Université de Montréal; Montréal Québec Canada
| | - Richard P. Allen
- Department of Neurology; The Johns Hopkins Bayview Medical Center; Baltimore MD USA
| | | | - Alex Desautels
- Centre d'Études Avancées en Médecine du Sommeil; Hôpital du Sacré-Cœur de Montréal; Montréal Québec Canada
- Department of Neurosciences; Université de Montréal; Montréal Québec Canada
| | - Patrick A. Dion
- Montreal Neurological Institute and McGill University; Montréal Québec Canada
- Department of Neurology and Neurosurgery; McGill University; Montréal Québec Canada
| | - Lan Xiong
- Laboratoire de Neurogénétique; Centre de Recherche; Institut Universitaire en Santé Mentale de Montréal; Montréal Québec Canada
- Département de Psychiatrie; Université de Montréal; Montréal Québec Canada
- Department of Neurology and Neurosurgery; McGill University; Montréal Québec Canada
| | - Guy A. Rouleau
- Montreal Neurological Institute and McGill University; Montréal Québec Canada
- Department of Human Genetics; McGill University; Montréal Québec Canada
- Department of Neurology and Neurosurgery; McGill University; Montréal Québec Canada
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Koo BB, Bagai K, Walters AS. Restless Legs Syndrome: Current Concepts about Disease Pathophysiology. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2016; 6:401. [PMID: 27536462 PMCID: PMC4961894 DOI: 10.7916/d83j3d2g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/07/2016] [Indexed: 01/31/2023]
Abstract
Background In the past few decades, much has been learned about the pathophysiology of restless legs syndrome (RLS). Investigators have studied neuropathology, imaging, electrophysiology, and genetics of RLS, identifying brain regions and biological systems affected in RLS. This manuscript will review RLS pathophysiology literature, examining the RLS state through consideration of the neuroanatomy, then the biological, organ, and genetic systems. Methods Pubmed (1966 to April 2016) was searched for the term “restless legs syndrome” cross-referenced with “pathophysiology,” “pathogenesis,” “pathology,” or “imaging.” English language papers were reviewed. Studies that focused on RLS in relation to another disease were not reviewed. Results Although there are no gross structural brain abnormalities in RLS, widespread brain areas are activated, including the pre- and post-central gyri, cingulate cortex, thalamus, and cerebellum. Pathologically, the most consistent finding is striatal iron deficiency in RLS patients. A host of other biological systems are also altered in RLS, including the dopaminergic, oxygen-sensing, opioid, glutamatergic, and serotonergic systems. Polymorphisms in genes including BTBD9 and MEIS1 are associated with RLS. Discussion RLS is a neurologic sensorimotor disorder that involves pathology, most notably iron deficiency, in motor and sensory brain areas. Brain areas not subserving movement or sensation such as the cingulate cortex and cerebellum are also involved. Other biological systems including the dopaminergic, oxygen-sensing, opioid, glutamatergic, and serotonergic systems are involved. Further research is needed to determine which of these anatomic locations or biological systems are affected primarily, and which are affected in a secondary response.
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Affiliation(s)
- Brian B Koo
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA; Department of Neurology, Connecticut Veterans Affairs Health System, West Haven, CT, USA; Yale Center for Neuroepidemiology & Clinical Neurological Research, New Haven, CT, USA
| | - Kanika Bagai
- Department of Neurology, Vanderbilt University, Nashville, TN, USA
| | - Arthur S Walters
- Department of Neurology, Vanderbilt University, Nashville, TN, USA
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DeAndrade MP, Trongnetrpunya A, Yokoi F, Cheetham CC, Peng N, Wyss JM, Ding M, Li Y. Electromyographic evidence in support of a knock-in mouse model of DYT1 Dystonia. Mov Disord 2016; 31:1633-1639. [PMID: 27241685 DOI: 10.1002/mds.26677] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/29/2016] [Accepted: 04/18/2016] [Indexed: 12/29/2022] Open
Abstract
INTRODUCTION DYT1 dystonia is an autosomal-dominant movement disorder characterized by abnormal, often repetitive, movements and postures. Its hallmark feature is sustained or intermittent contractions of muscles involving co-contractions of antagonist muscle pairs. The symptoms are relieved with the anticholinergic drug trihexyphenidyl. The primary mutation is a trinucleotide deletion (ΔGAG) in DYT1/TOR1A, which codes for torsinA. Previous studies showed that (1) heterozygous Dyt1 ΔGAG knock-in mice, which have an analogous mutation in the endogenous gene, exhibit motor deficits and altered corticostriatal synaptic plasticity in the brain and (2) these deficits can be rescued by trihexyphenidyl. However, brain imaging studies suggest that the Dyt1 knock-in mouse models nonmanifesting mutation carriers of DYT1 dystonia. The aim of this work was to examine the hallmark features of DYT1 dystonia in the Dyt1 knock-in mice by analyzing muscular activities. METHODS Wireless telemetry devices with biopotential channels were implanted to the bicep and the rectus femori muscles in Dyt1 knock-in mice, and muscular activities were recorded before and after trihexyphenidyl administration. RESULTS (1) Consistent with DYT1 dystonia patients, Dyt1 knock-in mice showed sustained contractions and co-contractions of the antagonistic bicep femoris and rectus femoris. (2) The abnormal muscle contractions were normalized by trihexyphenidyl. CONCLUSION The results suggest that the motor deficits in Dyt1 knock-in mice are likely produced by abnormal muscle contractions, and Dyt1 knock-in mice can potentially be used as a manifesting disease model to study pathophysiology and develop novel therapeutics. © 2016 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Mark P DeAndrade
- Department of Neurology, College of Medicine,, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Amy Trongnetrpunya
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, Florida, USA
| | - Fumiaki Yokoi
- Department of Neurology, College of Medicine,, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Chad C Cheetham
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Ning Peng
- Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - J Michael Wyss
- Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Mingzhou Ding
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, Florida, USA
| | - Yuqing Li
- Department of Neurology, College of Medicine,, College of Medicine, University of Florida, Gainesville, Florida, USA
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Winkelman JW, Blackwell T, Stone K, Ancoli-Israel S, Tranah GJ, Redline S. Genetic associations of periodic limb movements of sleep in the elderly for the MrOS sleep study. Sleep Med 2015; 16:1360-1365. [PMID: 26498236 DOI: 10.1016/j.sleep.2015.07.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 07/28/2015] [Accepted: 07/31/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The objective of this study was to assess the relationship between single-nucleotide polymorphisms associated with restless legs syndrome and periodic limb movements of sleep in a population cohort of elderly individuals. METHODS Single-nucleotide polymorphisms previously associated with periodic limb movements of sleep or restless legs syndrome were analyzed in 2356 white male participants in the Osteoporotic Fractures in Men Sleep Study cohort. The associations between single-nucleotide polymorphisms and polysomnographically measured periodic limb movement index ≥15 were examined with logistic regression adjusted for age, ancestry markers, and periodic limb movements of sleep risk factors. RESULTS Of the men in this cohort, 61% had a periodic limb movement index ≥15. Significant associations were observed between a periodic limb movement index ≥15 and the number of risk alleles for the two BTBD9 single-nucleotide polymorphisms (rs9357271[T], odds ratio [OR] = 1.38, 95% confidence interval [CI] 1.20-1.58; and rs3923809[A], OR = 1.43, 95% CI 1.26-1.63), one of the MEIS1 single-nucleotide polymorphisms (rs2300478[G], OR = 1.31, 95% CI 1.14-1.51) and the mitogen-activated protein kinase kinase 5 (MAP2K5)/Ski family transcriptional corepressor 1 (SKOR1) single-nucleotide polymorphism (rs1026732[G], OR = 1.16, 95% CI 1.02-1.31). In a multivariable model controlling for each of the two MEIS1 single-nucleotide polymorphisms, the rs6710341[A] single-nucleotide polymorphism became a significant risk allele (OR = 1.59, 95% CI 1.26-2.00). CONCLUSIONS Our findings confirm an association between the BTBD9, MEIS1, and MAP2K5/SKOR1 single-nucleotide polymorphisms and periodic limb movements of sleep in an elderly cohort not selected for the presence of restless legs syndrome.
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Affiliation(s)
- John W Winkelman
- Departments of Psychiatry and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Terri Blackwell
- Research Institute, California Pacific Medical Center, San Francisco, CA, USA
| | - Katie Stone
- Research Institute, California Pacific Medical Center, San Francisco, CA, USA
| | - Sonia Ancoli-Israel
- Departments of Psychiatry and Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Gregory J Tranah
- Research Institute, California Pacific Medical Center, San Francisco, CA, USA
| | - Susan Redline
- Departments of Medicine, Brigham and Women's Hospital and Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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