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Tamir S, Dye TJ, Witt RM. Sleep and Circadian Disturbances in Children With Neurodevelopmental Disorders. Semin Pediatr Neurol 2023; 48:101090. [PMID: 38065637 DOI: 10.1016/j.spen.2023.101090] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 12/18/2023]
Abstract
Sleep problems are highly prevalent in those with neurodevelopmental disorders (NDDs). We propose this is secondary to multiple factors that directly and indirectly negatively impact sleep and circadian processes in those with NDDs, which in turn, further perturbs development, resulting in a "developmental and sleep/circadian-related encephalopathy." In this review, we discuss select NDDs with known or suspected sleep and circadian phenotypes. We also highlight important considerations when evaluating and treating sleep and circadian disorders in these populations.
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Affiliation(s)
- Sharon Tamir
- University of Cincinnati College of Medicine, Cincinnati, OH; Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Thomas J Dye
- Division of Child Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Division of Pulmonary Medicine and the Sleep Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Center for Circadian Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Rochelle M Witt
- Division of Child Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Division of Pulmonary Medicine and the Sleep Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Center for Circadian Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH.
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2
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Byiers BJ, Merbler AM, Burkitt CC, Beisang A, Symons FJ. Preliminary assessment of the reliability and validity of infrared skin temperature measurements in Rett syndrome. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2023; 67:387-395. [PMID: 36744445 PMCID: PMC10251747 DOI: 10.1111/jir.13010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 12/02/2022] [Accepted: 01/04/2023] [Indexed: 06/11/2023]
Abstract
BACKGROUND As clinical trials for Rett syndrome are underway, there is a need to validate potential supplemental outcome measures that reflect important signs and symptoms. Autonomic dysfunction, particularly vasomotor dysfunction, is one potential area for which biomarkers could be developed. METHODS In the current study, infrared thermal images of hands and feet from 26 females with Rett syndrome (aged 62 months to 39 years), and 17 females without known intellectual, genetic or neurological disorders (aged 55 months to 39 years) were collected. Between-group differences in skin temperature, and temporal stability of skin temperature measures in the Rett syndrome group, and relationships between skin temperature measures and parent-reported and researcher-evaluated indicators of autonomic dysfunction were evaluated. RESULTS Between-group differences showed lower hand and foot temperatures in the Rett syndrome group. Hand temperature measurements were stable over time and were moderately correlated with parent-reported autonomic symptoms. Foot temperature measurements were more variable than hand temperatures but showed stronger correlations with parent-reported autonomic symptoms. CONCLUSIONS The results provide preliminary support for the reliability and validity of hand and foot skin temperature measures in Rett syndrome. Additional research is needed to replicate these results and evaluate the temporal stability of these measures over shorter time scales.
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Affiliation(s)
- B J Byiers
- Department of Educational Psychology, University of Minnesota, Minneapolis, MN, USA
| | - A M Merbler
- Department of Educational Psychology, University of Minnesota, Minneapolis, MN, USA
| | - C C Burkitt
- Gillette Children's Specialty Healthcare, St. Paul, MN, USA
| | - A Beisang
- Gillette Children's Specialty Healthcare, St. Paul, MN, USA
| | - F J Symons
- Department of Educational Psychology, University of Minnesota, Minneapolis, MN, USA
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3
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Zhang XY, Spruyt K. A meta-review of standard polysomnography parameters in Rett Syndrome. Front Neurol 2022; 13:963626. [PMID: 36203990 PMCID: PMC9530595 DOI: 10.3389/fneur.2022.963626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/01/2022] [Indexed: 11/26/2022] Open
Abstract
Rett Syndrome (RTT, OMIM 312750), a unique rare neurodevelopmental disorder, mostly affects females and causes severe multi-disabilities including poor sleep. This meta-analysis systematically reviewed the polysomnographic (PSG) data of individuals with RTT on both sleep macrostructure and sleep respiratory indexes and compared them to literature normative values. Studies were collected from PubMed, Web of Science, PsycINFO, Ebsco, Scopus, and Cochrane Library till 26 April 2022. Across 13 included studies, the 134 selected RTT cases were mostly females being MECP2 (n = 41) and CDKL5 (n = 4) positive. They were further stratified by gene, age, and clinical features. Findings of comparison with literature normative values suggested shorter total sleep time (TST) and sleep onset latency (SOL), twice as long wake after sleep onset (WASO) with lower sleep efficiency (SEI) in RTT, as well as increased non-rapid eye movement stage 3 (stage N3) and decreased rapid eye movement sleep. Based on limited data per stratifications, we found in RTT cases <5 years old lower stage N3, and in RTT cases >5 years old less WASO and more WASO in the epileptic strata. However, meta-results generated from studies designed with comparison groups only showed lower stage N1 in RTT than in healthy comparison, together with similar SEI and stage N3 to primary snoring subjects. For sleep respiratory indexes, severe disordered sleep breathing was confirmed across roughly all RTT strata. We are the first study to meta-analyze PSG data of subjects with RTT, illustrating shorter TST and aberrant sleep staging in RTT that may vary with age or the presence of epilepsy. Severe nocturnal hypoxemia with apneic events was also demonstrated. More studies are needed to explore and elucidate the pathophysiological mechanisms of these sleep findings in the future.
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Reviewing Evidence for the Relationship of EEG Abnormalities and RTT Phenotype Paralleled by Insights from Animal Studies. Int J Mol Sci 2021; 22:ijms22105308. [PMID: 34069993 PMCID: PMC8157853 DOI: 10.3390/ijms22105308] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/09/2021] [Accepted: 05/12/2021] [Indexed: 12/29/2022] Open
Abstract
Rett syndrome (RTT) is a rare neurodevelopmental disorder that is usually caused by mutations of the MECP2 gene. Patients with RTT suffer from severe deficits in motor, perceptual and cognitive domains. Electroencephalogram (EEG) has provided useful information to clinicians and scientists, from the very first descriptions of RTT, and yet no reliable neurophysiological biomarkers related to the pathophysiology of the disorder or symptom severity have been identified to date. To identify consistently observed and potentially informative EEG characteristics of RTT pathophysiology, and ascertain areas most worthy of further systematic investigation, here we review the literature for EEG abnormalities reported in patients with RTT and in its disease models. While pointing to some promising potential EEG biomarkers of RTT, our review identify areas of need to realize the potential of EEG including (1) quantitative investigation of promising clinical-EEG observations in RTT, e.g., shift of mu rhythm frequency and EEG during sleep; (2) closer alignment of approaches between patients with RTT and its animal models to strengthen the translational significance of the work (e.g., EEG measurements and behavioral states); (3) establishment of large-scale consortium research, to provide adequate Ns to investigate age and genotype effects.
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5
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Zhang X, Lin JS, Spruyt K. Sleep problems in Rett syndrome animal models: A systematic review. J Neurosci Res 2020; 99:529-544. [PMID: 32985711 DOI: 10.1002/jnr.24730] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/27/2020] [Accepted: 08/30/2020] [Indexed: 02/01/2023]
Abstract
Due to the discovery of Rett Syndrome (RTT) genetic mutations, animal models have been developed. Sleep research in RTT animal models may unravel novel neural mechanisms for this severe neurodevelopmental heritable rare disease. In this systematic literature review we summarize the findings on sleep research of 13 studies in animal models of RTT. We found disturbed efficacy and continuity of sleep in all genetically mutated models of mice, cynomolgus monkeys, and Drosophila. Models presented highly fragmented sleep with distinct differences in 24-hr sleep/wake cyclicity and circadian arrhythmicity. Overall, animal models mimic sleep complaints reported in individuals with RTT. However, contrary to human studies, in mutant mice, attenuated sleep delta waves, and sleep apneas in non-rapid eye movement sleep were reported. Future studies may focus on sleep structure and EEG alterations, potential central mechanisms involved in sleep fragmentation and the occurrence of sleep apnea across different sleep stages. Given that locomotor dysfunction is characteristic of individuals with RTT, studies may consider to integrate its potential impact on the behavioral analysis of sleep.
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Affiliation(s)
- Xinyan Zhang
- INSERM - School of Medicine, University Claude Bernard, Lyon, France
| | - Jian-Sheng Lin
- INSERM - School of Medicine, University Claude Bernard, Lyon, France
| | - Karen Spruyt
- INSERM - School of Medicine, University Claude Bernard, Lyon, France
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Dong HW, Erickson K, Lee JR, Merritt J, Fu C, Neul JL. Detection of neurophysiological features in female R255X MeCP2 mutation mice. Neurobiol Dis 2020; 145:105083. [PMID: 32927061 PMCID: PMC7572861 DOI: 10.1016/j.nbd.2020.105083] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 08/11/2020] [Accepted: 09/08/2020] [Indexed: 02/07/2023] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder (NDD) that is nearly always caused by loss of function mutations in Methyl-CpG-binding Protein 2 (MECP2) and shares many clinical features with other NDD. Genetic restoration of Mecp2 in symptomatic mice lacking MeCP2 expression can reverse symptoms, providing hope that disease modifying therapies can be identified for RTT. Effective and rapid clinical trial completion relies on well-defined clinical outcome measures and robust biomarkers of treatment responses. Studies on other NDD have found evidence of differences in neurophysiological measures that correlate with disease severity. However, currently there are no well-validated biomarkers in RTT to predict disease prognosis or treatment responses. To address this, we characterized neurophysiological features in a mouse model of RTT containing a knock-in nonsense mutation (p.R255X) in the Mecp2 locus. We found a variety of changes in heterozygous female Mecp2R255X/X mice including age-related changes in sleep/wake architecture, alterations in baseline EEG power, increased incidence of spontaneous epileptiform discharges, and changes in auditory evoked potentials. Furthermore, we identified association of some neurophysiological features with disease severity. These findings provide a set of potential non-invasive and translatable biomarkers that can be utilized in preclinical therapy trials in animal models of RTT and eventually within the context of clinical trials.
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Affiliation(s)
- Hong-Wei Dong
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Kirsty Erickson
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Jessica R Lee
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Jonathan Merritt
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Cary Fu
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Jeffrey L Neul
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
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Wintler T, Schoch H, Frank M, Peixoto L. Sleep, brain development, and autism spectrum disorders: Insights from animal models. J Neurosci Res 2020; 98:1137-1149. [PMID: 32215963 PMCID: PMC7199437 DOI: 10.1002/jnr.24619] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/07/2020] [Accepted: 02/29/2020] [Indexed: 01/28/2023]
Abstract
Sleep is an evolutionarily conserved and powerful drive, although its complete functions are still unknown. One possible function of sleep is that it promotes brain development. The amount of sleep is greatest during ages when the brain is rapidly developing, and sleep has been shown to influence critical period plasticity. This supports a role for sleep in brain development and suggests that abnormal sleep in early life may lead to abnormal development. Autism spectrum disorder (ASD) is the most prevalent neurodevelopmental disorder in the United States. It is estimated that insomnia affects 44%-86% of the ASD population, predicting the severity of ASD core symptoms and associated behavioral problems. Sleep problems impact the quality of life of both ASD individuals and their caregivers, thus it is important to understand why they are so prevalent. In this review, we explore the role of sleep in early life as a causal factor in ASD. First, we review fundamental steps in mammalian sleep ontogeny and regulation and how sleep influences brain development. Next, we summarize current knowledge gained from studying sleep in animal models of ASD. Ultimately, our goal is to highlight the importance of understanding the role of sleep in brain development and the use of animal models to provide mechanistic insight into the origin of sleep problems in ASD.
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Affiliation(s)
- Taylor Wintler
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
| | - Hannah Schoch
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
| | - Marcos Frank
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
| | - Lucia Peixoto
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
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8
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Fallah MS, Eubanks JH. Seizures in Mouse Models of Rare Neurodevelopmental Disorders. Neuroscience 2020; 445:50-68. [PMID: 32059984 DOI: 10.1016/j.neuroscience.2020.01.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/28/2020] [Accepted: 01/29/2020] [Indexed: 02/07/2023]
Abstract
Genetic neurodevelopmental disorders - that often include epilepsy as part of their phenotype - are a heterogeneous and clinically challenging spectrum of disorders in children. Although seizures often contribute significantly to morbidity in these affected populations, the mechanisms of epileptogenesis in these conditions remain poorly understood. Different model systems have been developed to aid in unraveling these mechanisms, which include a number of specific mutant mouse lines which genocopy specific general types of mutations present in patients. These mouse models have not only allowed for assessments of behavioral and electrographic seizure phenotypes to be ascertained, but also have allowed effects on the neurodevelopmental alterations and cognitive impairments associated with these disorders to be examined. In addition, these models play a role in advancing our understanding of these epileptic processes and developing preclinical therapeutics. The concordance of seizure phenotypes - in a select group of rare, genetic, neurodevelopmental disorders and epileptic encephalopathies - found between human patients and their model counterparts will be summarized. This review aims to assess whether models of Rett syndrome, CDKL5 deficiency disorder, Fragile-X syndrome, Dravet syndrome, and Ohtahara syndrome phenocopy the seizures seen in human patients.
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Affiliation(s)
- Merrick S Fallah
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, 399 Bathurst Street, Toronto, Ontario M5T 0S8, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - James H Eubanks
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, 399 Bathurst Street, Toronto, Ontario M5T 0S8, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Surgery (Neurosurgery), University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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9
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Missig G, McDougle CJ, Carlezon WA. Sleep as a translationally-relevant endpoint in studies of autism spectrum disorder (ASD). Neuropsychopharmacology 2020; 45:90-103. [PMID: 31060044 PMCID: PMC6879602 DOI: 10.1038/s41386-019-0409-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 04/16/2019] [Accepted: 04/19/2019] [Indexed: 02/07/2023]
Abstract
Sleep has numerous advantages for aligning clinical and preclinical (basic neuroscience) studies of neuropsychiatric illness. Sleep has high translational relevance, because the same endpoints can be studied in humans and laboratory animals. In addition, sleep experiments are conducive to continuous data collection over long periods (hours/days/weeks) and can be based on highly objective neurophysiological measures. Here, we provide a translationally-oriented review on what is currently known about sleep in the context of autism spectrum disorder (ASD), including ASD-related conditions, thought to have genetic, environmental, or mixed etiologies. In humans, ASD is frequently associated with comorbid medical conditions including sleep disorders. Animal models used in the study of ASD frequently recapitulate dysregulation of sleep and biological (diurnal, circadian) rhythms, suggesting common pathophysiologies across species. As our understanding of the neurobiology of ASD and sleep each become more refined, it is conceivable that sleep-derived metrics may offer more powerful biomarkers of altered neurophysiology in ASD than the behavioral tests currently used in humans or lab animals. As such, the study of sleep in animal models for ASD may enable fundamentally new insights on the condition and represent a basis for strategies that enable the development of more effective therapeutics.
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Affiliation(s)
- Galen Missig
- 0000 0000 8795 072Xgrid.240206.2Basic Neuroscience Division, Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA USA
| | - Christopher J. McDougle
- 0000 0004 0386 9924grid.32224.35Lurie Center for Autism, Massachusetts General Hospital, Lexington, MA USA ,000000041936754Xgrid.38142.3cDepartment of Psychiatry, Harvard Medical School, Boston, MA USA
| | - William A. Carlezon
- 0000 0000 8795 072Xgrid.240206.2Basic Neuroscience Division, Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA USA
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10
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Wither RG, Colic S, Bardakjian BL, Snead OC, Zhang L, Eubanks JH. Electrographic and pharmacological characterization of a progressive epilepsy phenotype in female MeCP2-deficient mice. Epilepsy Res 2018; 140:177-183. [PMID: 29414525 DOI: 10.1016/j.eplepsyres.2018.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 01/05/2018] [Accepted: 01/11/2018] [Indexed: 11/27/2022]
Abstract
Rett Syndrome is a neurodevelopmental disorder caused primarily by mutations in the gene encoding Methyl-CpG-binding protein 2 (MECP2). Spontaneous epileptiform activity is a common co-morbidity present in Rett syndrome, and hyper-excitable neural networks are present in MeCP2-deficient mouse models of Rett syndrome. In this study we conducted a longitudinal assessment of spontaneous cortical electrographic discharges in female MeCP2-deficient mice and defined the pharmacological responsiveness of these discharges to anti-convulsant drugs. Our data show that cortical discharge activity in female MeCP2-deficient mice progressively increases in severity as the mice age, with discharges being more frequent and of longer durations at 19-24 months of age compared to 3 months of age. Semiologically and pharmacologically, this basal discharge activity in female MeCP2-deficient mice displayed electroclinical properties consistent with absence epilepsy. Only rarely were convulsive seizures observed in these mice at any age. Since absence epilepsy is infrequently observed in Rett syndrome patients, these results indicate that the predominant spontaneous electroclinical phenotype of MeCP2-deficient mice we examined does not faithfully recapitulate the most prevalent seizure types observed in affected patients.
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Affiliation(s)
- Robert G Wither
- Division of Genetics and Development, Krembil Research Institute, University Health Network, 399 Bathurst Street, Toronto, Ontario, M5T 2S8, Canada; Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Sinisa Colic
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Berj L Bardakjian
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - O Carter Snead
- Department of Medicine (Neurology), University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Liang Zhang
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, 399 Bathurst Street, Toronto, Ontario, M5T 2S8, Canada; University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - James H Eubanks
- Division of Genetics and Development, Krembil Research Institute, University Health Network, 399 Bathurst Street, Toronto, Ontario, M5T 2S8, Canada; University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Surgery (Neurosurgery), University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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11
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O'Callaghan EK, Green EW, Franken P, Mongrain V. Omics Approaches in Sleep-Wake Regulation. Handb Exp Pharmacol 2018; 253:59-81. [PMID: 29796779 DOI: 10.1007/164_2018_125] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Although sleep seems an obvious and simple behaviour, it is extremely complex involving numerous interactions both at the neuronal and the molecular levels. While we have gained detailed insight into the molecules and neuronal networks responsible for the circadian organization of sleep and wakefulness, the molecular underpinnings of the homeostatic aspect of sleep regulation are still unknown and the focus of a considerable research effort. In the last 20 years, the development of techniques allowing the simultaneous measurement of hundreds to thousands of molecular targets (i.e. 'omics' approaches) has enabled the unbiased study of the molecular pathways regulated by and regulating sleep. In this chapter, we will review how the different omics approaches, including transcriptomics, epigenomics, proteomics, and metabolomics, have advanced sleep research. We present relevant data in the framework of the two-process model in which circadian and homeostatic processes interact to regulate sleep. The integration of the different omics levels, known as 'systems genetics', will eventually lead to a better understanding of how information flows from the genome, to molecules, to networks, and finally to sleep both in health and disease.
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Affiliation(s)
- Emma K O'Callaghan
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada.,Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
| | - Edward W Green
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Paul Franken
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Valérie Mongrain
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada. .,Department of Neuroscience, Université de Montréal, Montreal, QC, Canada.
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12
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Thomas AM, Schwartz MD, Saxe MD, Kilduff TS. Cntnap2 Knockout Rats and Mice Exhibit Epileptiform Activity and Abnormal Sleep-Wake Physiology. Sleep 2017; 40:2661545. [PMID: 28364455 DOI: 10.1093/sleep/zsw026] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2016] [Indexed: 11/12/2022] Open
Abstract
Study Objectives Although recent innovations have enabled modification of the rat genome, it is unclear whether enhanced utility of rodents as human disease models will result. We compared electroencephalogram (EEG) and behavioral phenotypes of rats and mice with homozygous deletion of Cntnap2, a gene associated with cortical dysplasia-focal epilepsy (CDFE) and autism spectrum disorders (ASD). Methods Male contactin-associated protein-like 2 (Cntnap2) knockout (KO) and wild-type (WT) rats and male Cntnap2 KO and WT mice were implanted with telemeters to record EEG, electromyogram, body temperature, and locomotor activity. Animals were subjected to a test battery for ASD-related behaviors, followed by 24-hr EEG recordings that were analyzed for sleep-wake parameters and subjected to spectral analysis. Results Cntnap2 KO rats exhibited severe motor seizures, hyperactivity, and increased consolidation of wakefulness and REM sleep. By contrast, Cntnap2 KO mice demonstrated absence seizure-like events, hypoactivity, and wake fragmentation. Although seizures observed in Cntnap2 KO rats were more similar to those in CDFE patients than in KO mice, neither model fully recapitulated the full spectrum of disease symptoms. However, KOs in both species had reduced spectral power in the alpha (9-12 Hz) range during wake, suggesting a conserved EEG biomarker. Conclusions Deletion of Cntnap2 impacts similar behaviors and EEG measures in rats and mice, but with profound differences in nature and phenotypic severity. These observations highlight the importance of cross-species comparisons to understand conserved gene functions and the limitations of single- species models to provide translational insights relevant to human diseases.
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Affiliation(s)
- Alexia M Thomas
- Biosciences Division, Center for Neuroscience, SRI International, Menlo Park, CA
| | - Michael D Schwartz
- Biosciences Division, Center for Neuroscience, SRI International, Menlo Park, CA
| | - Michael D Saxe
- Pharma Research and Early Development, Neuroscience, Ophthalmology and Rare Disease DTA, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Thomas S Kilduff
- Biosciences Division, Center for Neuroscience, SRI International, Menlo Park, CA
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13
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Bin NR, Song H, Wu C, Lau M, Sugita S, Eubanks JH, Zhang L. Continuous Monitoring via Tethered Electroencephalography of Spontaneous Recurrent Seizures in Mice. Front Behav Neurosci 2017; 11:172. [PMID: 28959196 PMCID: PMC5603658 DOI: 10.3389/fnbeh.2017.00172] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 08/31/2017] [Indexed: 12/16/2022] Open
Abstract
We describe here a simple, cost-effective apparatus for continuous tethered electroencephalographic (EEG) monitoring of spontaneous recurrent seizures in mice. We used a small, low torque slip ring as an EEG commutator, mounted the slip ring onto a standard mouse cage and connected rotary wires of the slip ring directly to animal's implanted headset. Modifications were made in the cage to allow for a convenient installation of the slip ring and accommodation of animal ambient activity. We tested the apparatus for hippocampal EEG recordings in adult C57 black mice. Spontaneous recurrent seizures were induced using extended hippocampal kindling (≥95 daily stimulation). Control animals underwent similar hippocampal electrode implantations but no stimulations were given. Combined EEG and webcam monitoring were performed for 24 h daily for 5–9 consecutive days. During the monitoring periods, the animals moved and accessed water and food freely and showed no apparent restriction in ambient cage activities. Ictal-like hippocampal EEG discharges and concurrent convulsive behaviors that are characteristics of spontaneous recurrent seizures were reliably recorded in a majority of the monitoring experiments in extendedly kindled but not in control animals. However, 1–2 rotary wires were disconnected from the implanted headset in some animals after continuous recordings for ≥5 days. The key features and main limitations of our recording apparatus are discussed.
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Affiliation(s)
- Na-Ryum Bin
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Physiology, University of TorontoToronto, ON, Canada
| | - Hongmei Song
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Neurosurgery, The First Hospital of Jilin UniversityJilin, China
| | - Chiping Wu
- Krembil Research Institute, University Health NetworkToronto, ON, Canada
| | - Marcus Lau
- Krembil Research Institute, University Health NetworkToronto, ON, Canada
| | - Shuzo Sugita
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Physiology, University of TorontoToronto, ON, Canada
| | - James H Eubanks
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Physiology, University of TorontoToronto, ON, Canada.,Division of Neurosurgery, Department of Surgery, University of TorontoToronto, ON, Canada.,The Epilepsy Research Program of Ontario Brain InstituteToronto, ON, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,The Epilepsy Research Program of Ontario Brain InstituteToronto, ON, Canada.,Division of Neurology, Department of Medicine, University of TorontoToronto, ON, Canada
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Meyer CW, Ootsuka Y, Romanovsky AA. Body Temperature Measurements for Metabolic Phenotyping in Mice. Front Physiol 2017; 8:520. [PMID: 28824441 PMCID: PMC5534453 DOI: 10.3389/fphys.2017.00520] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 07/06/2017] [Indexed: 01/01/2023] Open
Abstract
Key Points Rectal probing is subject to procedural bias. This method is suitable for first-line phenotyping, provided probe depth and measurement duration are standardized. It is also useful for detecting individuals with out-of-range body temperatures (during hypothermia, torpor).The colonic temperature attained by inserting the probe >2 cm deep is a measure of deep (core) body temperature.IR imaging of the skin is useful for detecting heat leaks and autonomous thermoregulatory alterations, but it does not measure body temperature.Temperature of the hairy or shaved skin covering the inter-scapular brown adipose tissue can be used as a measure of BAT thermogenesis. However, obtaining such measurements of sufficient quality is very difficult, and interpreting them can be tricky. Temperature differences between the inter-scapular and lumbar areas can be a better measure of the thermogenic activity of inter-scapular brown adipose tissue.Implanted probes for precise determination of BAT temperature (changes) should be fixed close to the Sulzer's vein. For measurement of BAT thermogenesis, core body temperature and BAT temperature should be recorded simultaneously.Tail temperature is suitable to compare the presence or absence of vasoconstriction or vasodilation.Continuous, longitudinal monitoring of core body temperature is preferred over single probing, as the readings are taken in a non-invasive, physiological context.Combining core body temperature measurements with metabolic rate measurements yields insights into the interplay between heat production and heat loss (thermal conductance), potentially revealing novel thermoregulatory phenotypes. Endothermic organisms rely on tightly balanced energy budgets to maintain a regulated body temperature and body mass. Metabolic phenotyping of mice, therefore, often includes the recording of body temperature. Thermometry in mice is conducted at various sites, using various devices and measurement practices, ranging from single-time probing to continuous temperature imaging. Whilst there is broad agreement that body temperature data is of value, procedural considerations of body temperature measurements in the context of metabolic phenotyping are missing. Here, we provide an overview of the various methods currently available for gathering body temperature data from mice. We explore the scope and limitations of thermometry in mice, with the hope of assisting researchers in the selection of appropriate approaches, and conditions, for comprehensive mouse phenotypic analyses.
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Affiliation(s)
- Carola W Meyer
- Department of Pharmacology, Max-Planck Institute for Heart and Lung ResearchBad Nauheim, Germany
| | - Youichirou Ootsuka
- Centre for Neuroscience, School of Medicine, Flinders University of South AustraliaAdelaide, SA, Australia
| | - Andrej A Romanovsky
- FeverLab, St. Joseph's Hospital and Medical CenterPhoenix, AZ, United States
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15
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Colic S, Wither RG, Lang M, Zhang L, Eubanks JH, Bardakjian BL. Prediction of antiepileptic drug treatment outcomes using machine learning. J Neural Eng 2016; 14:016002. [PMID: 27900948 DOI: 10.1088/1741-2560/14/1/016002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Antiepileptic drug (AED) treatments produce inconsistent outcomes, often necessitating patients to go through several drug trials until a successful treatment can be found. This study proposes the use of machine learning techniques to predict epilepsy treatment outcomes of commonly used AEDs. APPROACH Machine learning algorithms were trained and evaluated using features obtained from intracranial electroencephalogram (iEEG) recordings of the epileptiform discharges observed in Mecp2-deficient mouse model of the Rett Syndrome. Previous work have linked the presence of cross-frequency coupling (I CFC) of the delta (2-5 Hz) rhythm with the fast ripple (400-600 Hz) rhythm in epileptiform discharges. Using the I CFC to label post-treatment outcomes we compared support vector machines (SVMs) and random forest (RF) machine learning classifiers for providing likelihood scores of successful treatment outcomes. MAIN RESULTS (a) There was heterogeneity in AED treatment outcomes, (b) machine learning techniques could be used to rank the efficacy of AEDs by estimating likelihood scores for successful treatment outcome, (c) I CFC features yielded the most effective a priori identification of appropriate AED treatment, and (d) both classifiers performed comparably. SIGNIFICANCE Machine learning approaches yielded predictions of successful drug treatment outcomes which in turn could reduce the burdens of drug trials and lead to substantial improvements in patient quality of life.
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Affiliation(s)
- Sinisa Colic
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S-3G4, Canada
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16
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Herrera JA, Ward CS, Wehrens XH, Neul JL. Methyl-CpG binding-protein 2 function in cholinergic neurons mediates cardiac arrhythmogenesis. Hum Mol Genet 2016; 25:4983-4995. [PMID: 28159985 PMCID: PMC6078594 DOI: 10.1093/hmg/ddw326] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/20/2016] [Accepted: 09/21/2016] [Indexed: 01/22/2023] Open
Abstract
Sudden unexpected death occurs in one quarter of deaths in Rett Syndrome (RTT), a neurodevelopmental disorder caused by mutations in Methyl-CpG-binding protein 2 (MECP2). People with RTT show a variety of autonomic nervous system (ANS) abnormalities and mouse models show similar problems including QTc interval prolongation and hypothermia. To explore the role of cardiac problems in sudden death in RTT, we characterized cardiac rhythm in mice lacking Mecp2 function. Male and female mutant mice exhibited spontaneous cardiac rhythm abnormalities including bradycardic events, sinus pauses, atrioventricular block, premature ventricular contractions, non-sustained ventricular arrhythmias, and increased heart rate variability. Death was associated with spontaneous cardiac arrhythmias and complete conduction block. Atropine treatment reduced cardiac arrhythmias in mutant mice, implicating overactive parasympathetic tone. To explore the role of MeCP2 within the parasympathetic neurons, we selectively removed MeCP2 function from cholinergic neurons (MeCP2 ChAT KO), which recapitulated the cardiac rhythm abnormalities, hypothermia, and early death seen in RTT male mice. Conversely, restoring MeCP2 only in cholinergic neurons rescued these phenotypes. Thus, MeCP2 in cholinergic neurons is necessary and sufficient for autonomic cardiac control, thermoregulation, and survival, and targeting the overactive parasympathetic system may be a useful therapeutic strategy to prevent sudden unexpected death in RTT.
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Affiliation(s)
- José A. Herrera
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA
- Jan and Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, USA
| | - Christopher S. Ward
- Jan and Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, USA
| | - Xander H.T. Wehrens
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA
- Cardiovascular Research Institute
- Departments of Medicine
- Molecular Physiology and Biophysics
- Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Jeffrey L. Neul
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA
- Jan and Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, USA
- Molecular Physiology and Biophysics
- Neuroscience
- Human and Molecular Genetics
- Pediatrics, Baylor College of Medicine, Houston, TX, USA
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17
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Veeraragavan S, Wan YW, Connolly DR, Hamilton SM, Ward CS, Soriano S, Pitcher MR, McGraw CM, Huang SG, Green JR, Yuva LA, Liang AJ, Neul JL, Yasui DH, LaSalle JM, Liu Z, Paylor R, Samaco RC. Loss of MeCP2 in the rat models regression, impaired sociability and transcriptional deficits of Rett syndrome. Hum Mol Genet 2016; 25:3284-3302. [PMID: 27365498 PMCID: PMC5179927 DOI: 10.1093/hmg/ddw178] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/18/2016] [Accepted: 06/08/2016] [Indexed: 01/31/2023] Open
Abstract
Mouse models of the transcriptional modulator Methyl-CpG-Binding Protein 2 (MeCP2) have advanced our understanding of Rett syndrome (RTT). RTT is a 'prototypical' neurodevelopmental disorder with many clinical features overlapping with other intellectual and developmental disabilities (IDD). Therapeutic interventions for RTT may therefore have broader applications. However, the reliance on the laboratory mouse to identify viable therapies for the human condition may present challenges in translating findings from the bench to the clinic. In addition, the need to identify outcome measures in well-chosen animal models is critical for preclinical trials. Here, we report that a novel Mecp2 rat model displays high face validity for modelling psychomotor regression of a learned skill, a deficit that has not been shown in Mecp2 mice. Juvenile play, a behavioural feature that is uniquely present in rats and not mice, is also impaired in female Mecp2 rats. Finally, we demonstrate that evaluating the molecular consequences of the loss of MeCP2 in both mouse and rat may result in higher predictive validity with respect to transcriptional changes in the human RTT brain. These data underscore the similarities and differences caused by the loss of MeCP2 among divergent rodent species which may have important implications for the treatment of individuals with disease-causing MECP2 mutations. Taken together, these findings demonstrate that the Mecp2 rat model is a complementary tool with unique features for the study of RTT and highlight the potential benefit of cross-species analyses in identifying potential disease-relevant preclinical outcome measures.
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Affiliation(s)
- Surabi Veeraragavan
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Ying-Wooi Wan
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Daniel R Connolly
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Christopher S Ward
- Department of Pediatrics, Section of Neurology
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Sirena Soriano
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Meagan R Pitcher
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Christopher M McGraw
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Sharon G Huang
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Lisa A Yuva
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Agnes J Liang
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Jeffrey L Neul
- Department of Pediatrics, Section of Neurology
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Dag H Yasui
- Rowe Program in Human Genetics, University of California Davis, Davis, CA, USA
| | - Janine M LaSalle
- Rowe Program in Human Genetics, University of California Davis, Davis, CA, USA
| | - Zhandong Liu
- Department of Pediatrics, Section of Neurology
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Rodney C Samaco
- Department of Molecular and Human Genetics
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
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18
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Zhang L, Wither RG, Lang M, Wu C, Sidorova-Darmos E, Netchev H, Matolcsy CB, Snead OC, Eubanks JH. A Role for Diminished GABA Transporter Activity in the Cortical Discharge Phenotype of MeCP2-Deficient Mice. Neuropsychopharmacology 2016; 41:1467-76. [PMID: 26499511 PMCID: PMC4832024 DOI: 10.1038/npp.2015.323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 09/13/2015] [Accepted: 10/01/2015] [Indexed: 12/14/2022]
Abstract
Cortical network hyper-excitability is a common phenotype in mouse models lacking the transcriptional regulator methyl-CPG-binding protein 2 (MeCP2). Here, we implicate enhanced GABAB receptor activity stemming from diminished cortical expression of the GABA transporter GAT-1 in the genesis of this network hyper-excitability. We found that administering the activity-dependent GABAB receptor allosteric modulator GS-39783 to female Mecp2(+/-) mice at doses producing no effect in wild-type mice strongly potentiated their basal rates of spontaneous cortical discharge activity. Consistently, administering the GABAB receptor antagonist CGP-35348 significantly decreased basal discharge activity in these mice. Expression analysis revealed that while GABAB or extra-synaptic GABAA receptor prevalence is preserved in the MeCP2-deficient cortex, the expression of GAT-1 is significantly reduced from wild-type levels. This decrease in GAT-1 expression is consequential, as low doses of the GAT-1 inhibitor NO-711 that had no effects in wild-type mice strongly exacerbated cortical discharge activity in female Mecp2(+/-) mice. Taken together, these data indicate that the absence of MeCP2 leads to decreased cortical levels of the GAT-1 GABA transporter, which facilitates cortical network hyper-excitability in MeCP2-deficient mice by increasing the activity of cortical GABAB receptors.
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Affiliation(s)
- Liang Zhang
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Robert G Wither
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Min Lang
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Chiping Wu
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
| | - Elena Sidorova-Darmos
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Hristo Netchev
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
| | - Catherine B Matolcsy
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
| | - Orlando Carter Snead
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - James H Eubanks
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada,Department of Surgery (Neurosurgery), University of Toronto, Toronto, ON, Canada,Toronto Western Hospital, 8KD-417, 60 Leonard Avenue, Toronto, ON M5T 2S8, Canada, Tel: +1 416 603 5800, ext. 2933, Fax: +1 416 603 5745, E-mail:
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19
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Colic S, Wither RG, Eubanks JH, Bardakjian BL. Support vector machines using EEG features of cross-frequency coupling can predict treatment outcome in Mecp2-deficient mice. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:5606-9. [PMID: 26737563 DOI: 10.1109/embc.2015.7319663] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Anti-convulsive drug treatments of epilepsy typically produce varied outcomes from one patient to the next, often necessitating patients to go through several anticonvulsive drug trials until an appropriate treatment is found. The focus of this study is to predict treatment outcome using a priori electroencephalogram (EEG) features for a rare genetic model of epilepsy seen in patients with Rett Syndrome. Previous work on Mecp2-deficient mice, exhibiting the symptoms of Rett syndrome, have revealed EEG-based biomarkers that track the pathology well. Specifically the presence of cross-frequency coupling of the delta-like (3-6 Hz) frequency range phase with the fast ripple (400 - 600 Hz) frequency range amplitude in long duration discharges was found to track seizure pathology. Support Vector Machines (SVM) were trained with features generated from phase-amplitude comodulograms and tested on (n=6) Mecp2-deficient mice to predict treatment outcome to Midazolam, a commonly used anti-convulsive drug. Using SVMs it was shown that it is possible to generate a likelihood score to predict treatment outcomes on all of the animal subjects. Identifying the most appropriate treatment a priori would potentially lead to improved treatment outcomes.
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20
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Wang J, Wu C, Peng J, Patel N, Huang Y, Gao X, Aljarallah S, Eubanks JH, McDonald R, Zhang L. Early-Onset Convulsive Seizures Induced by Brain Hypoxia-Ischemia in Aging Mice: Effects of Anticonvulsive Treatments. PLoS One 2015; 10:e0144113. [PMID: 26630670 PMCID: PMC4668036 DOI: 10.1371/journal.pone.0144113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 11/15/2015] [Indexed: 12/27/2022] Open
Abstract
Aging is associated with an increased risk of seizures/epilepsy. Stroke (ischemic or hemorrhagic) and cardiac arrest related brain injury are two major causative factors for seizure development in this patient population. With either etiology, seizures are a poor prognostic factor. In spite of this, the underlying pathophysiology of seizure development is not well understood. In addition, a standardized treatment regimen with anticonvulsants and outcome assessments following treatment has yet to be established for these post-ischemic seizures. Previous studies have modeled post-ischemic seizures in adult rodents, but similar studies in aging/aged animals, a group that mirrors a higher risk elderly population, remain sparse. Our study therefore aimed to investigate early-onset seizures in aging animals using a hypoxia-ischemia (HI) model. Male C57 black mice 18-20-month-old underwent a unilateral occlusion of the common carotid artery followed by a systemic hypoxic episode (8% O2 for 30 min). Early-onset seizures were detected using combined behavioral and electroencephalographic (EEG) monitoring. Brain injury was assessed histologically at different times post HI. Convulsive seizures were observed in 65% of aging mice post-HI but not in control aging mice following either sham surgery or hypoxia alone. These seizures typically occurred within hours of HI and behaviorally consisted of jumping, fast running, barrel-rolling, and/or falling (loss of the righting reflex) with limb spasms. No evident discharges during any convulsive seizures were seen on cortical-hippocampal EEG recordings. Seizure development was closely associated with acute mortality and severe brain injury on brain histological analysis. Intra-peritoneal injections of lorazepam and fosphenytoin suppressed seizures and improved survival but only when applied prior to seizure onset and not after. These findings together suggest that seizures are a major contributing factor to acute mortality in aging mice following severe brain ischemia and that early anticonvulsive treatment may prevent seizure genesis and improve overall outcomes.
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Affiliation(s)
- Justin Wang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Chiping Wu
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jessie Peng
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Nisarg Patel
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Yayi Huang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Xiaoxing Gao
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Salman Aljarallah
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Neurology Unit, Department of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - James H. Eubanks
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Surgery (Neurosurgery), University of Toronto, Toronto, Ontario, Canada
| | - Robert McDonald
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Liang Zhang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Departments of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
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21
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Infarinato F, Rahman A, Del Percio C, Lamberty Y, Bordet R, Richardson JC, Forloni G, Drinkenburg W, Lopez S, Aujard F, Babiloni C, Pifferi F. On-Going Frontal Alpha Rhythms Are Dominant in Passive State and Desynchronize in Active State in Adult Gray Mouse Lemurs. PLoS One 2015; 10:e0143719. [PMID: 26618512 PMCID: PMC4664384 DOI: 10.1371/journal.pone.0143719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 11/09/2015] [Indexed: 11/18/2022] Open
Abstract
The gray mouse lemur (Microcebus murinus) is considered a useful primate model for translational research. In the framework of IMI PharmaCog project (Grant Agreement n°115009, www.pharmacog.org), we tested the hypothesis that spectral electroencephalographic (EEG) markers of motor and locomotor activity in gray mouse lemurs reflect typical movement-related desynchronization of alpha rhythms (about 8–12 Hz) in humans. To this aim, EEG (bipolar electrodes in frontal cortex) and electromyographic (EMG; bipolar electrodes sutured in neck muscles) data were recorded in 13 male adult (about 3 years) lemurs. Artifact-free EEG segments during active state (gross movements, exploratory movements or locomotor activity) and awake passive state (no sleep) were selected on the basis of instrumental measures of animal behavior, and were used as an input for EEG power density analysis. Results showed a clear peak of EEG power density at alpha range (7–9 Hz) during passive state. During active state, there was a reduction in alpha power density (8–12 Hz) and an increase of power density at slow frequencies (1–4 Hz). Relative EMG activity was related to EEG power density at 2–4 Hz (positive correlation) and at 8–12 Hz (negative correlation). These results suggest for the first time that the primate gray mouse lemurs and humans may share basic neurophysiologic mechanisms of synchronization of frontal alpha rhythms in awake passive state and their desynchronization during motor and locomotor activity. These EEG markers may be an ideal experimental model for translational basic (motor science) and applied (pharmacological and non-pharmacological interventions) research in Neurophysiology.
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Affiliation(s)
| | - Anisur Rahman
- UMR 7179 Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle, Brunoy, France
| | | | - Yves Lamberty
- UCB Pharma s.a., Neuroscience Therapeutic Area, Braine l'Alleud, Belgium
| | - Regis Bordet
- L'Université Lille 2 Droit et Santé, Lille, France
| | - Jill C. Richardson
- Neurosciences Therapeutic Area Unit, GlaxoSmithKline R&D, Gunnels Wood Road, Stevenage, United Kingdom
| | - Gianluigi Forloni
- Department of Neurodegeneration, Mario Negri Institute, Milan, Italy
| | | | - Susanna Lopez
- Department of Physiology and Pharmacology, University of Rome "La Sapienza", Rome, Italy
| | - Fabienne Aujard
- UMR 7179 Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle, Brunoy, France
| | - Claudio Babiloni
- IRCCS San Raffaele Pisana, Rome, Italy
- Department of Physiology and Pharmacology, University of Rome "La Sapienza", Rome, Italy
- * E-mail:
| | - Fabien Pifferi
- UMR 7179 Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle, Brunoy, France
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22
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Tsuchiya Y, Minami Y, Umemura Y, Watanabe H, Ono D, Nakamura W, Takahashi T, Honma S, Kondoh G, Matsuishi T, Yagita K. Disruption of MeCP2 attenuates circadian rhythm in CRISPR/Cas9-based Rett syndrome model mouse. Genes Cells 2015; 20:992-1005. [DOI: 10.1111/gtc.12305] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 08/23/2015] [Indexed: 02/01/2023]
Affiliation(s)
- Yoshiki Tsuchiya
- Department of Physiology and Systems Bioscience; Kyoto Prefectural University of Medicine; Kyoto 602-8566 Japan
| | - Yoichi Minami
- Department of Physiology and Systems Bioscience; Kyoto Prefectural University of Medicine; Kyoto 602-8566 Japan
| | - Yasuhiro Umemura
- Department of Physiology and Systems Bioscience; Kyoto Prefectural University of Medicine; Kyoto 602-8566 Japan
| | - Hitomi Watanabe
- Laboratory of Animal Experiments for Regeneration; Institute for Frontier Medical Sciences; Kyoto University; Kyoto 606-8507 Japan
| | - Daisuke Ono
- Department of Chronomedicine; Hokkaido University Graduate School of Medicine; Sapporo 060-8638 Japan
| | - Wataru Nakamura
- Laboratory of Oral Chronobiology; Graduate School of Dentistry; Osaka University; Suita Osaka 565-0871 Japan
| | - Tomoyuki Takahashi
- Department of Pediatrics and Child Health; Kurume University School of Medicine; Kurume 830-0011 Japan
| | - Sato Honma
- Department of Chronomedicine; Hokkaido University Graduate School of Medicine; Sapporo 060-8638 Japan
| | - Gen Kondoh
- Laboratory of Animal Experiments for Regeneration; Institute for Frontier Medical Sciences; Kyoto University; Kyoto 606-8507 Japan
| | - Toyojiro Matsuishi
- Department of Pediatrics and Child Health; Kurume University School of Medicine; Kurume 830-0011 Japan
| | - Kazuhiro Yagita
- Department of Physiology and Systems Bioscience; Kyoto Prefectural University of Medicine; Kyoto 602-8566 Japan
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23
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Ammanuel S, Chan WC, Adler DA, Lakshamanan BM, Gupta SS, Ewen JB, Johnston MV, Marcus CL, Naidu S, Kadam SD. Heightened Delta Power during Slow-Wave-Sleep in Patients with Rett Syndrome Associated with Poor Sleep Efficiency. PLoS One 2015; 10:e0138113. [PMID: 26444000 PMCID: PMC4596813 DOI: 10.1371/journal.pone.0138113] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 08/25/2015] [Indexed: 12/31/2022] Open
Abstract
Sleep problems are commonly reported in Rett syndrome (RTT); however the electroencephalographic (EEG) biomarkers underlying sleep dysfunction are poorly understood. The aim of this study was to analyze the temporal evolution of quantitative EEG (qEEG) biomarkers in overnight EEGs recorded from girls (2–9 yrs. old) diagnosed with RTT using a non-traditional automated protocol. In this study, EEG spectral analysis identified high delta power cycles representing slow wave sleep (SWS) in 8–9h overnight sleep EEGs from the frontal, central and occipital leads (AP axis), comparing age-matched girls with and without RTT. Automated algorithms quantitated the area under the curve (AUC) within identified SWS cycles for each spectral frequency wave form. Both age-matched RTT and control EEGs showed similar increasing trends for recorded delta wave power in the EEG leads along the antero-posterior (AP). RTT EEGs had significantly fewer numbers of SWS sleep cycles; therefore, the overall time spent in SWS was also significantly lower in RTT. In contrast, the AUC for delta power within each SWS cycle was significantly heightened in RTT and remained heightened over consecutive cycles unlike control EEGs that showed an overnight decrement of delta power in consecutive cycles. Gamma wave power associated with these SWS cycles was similar to controls. However, the negative correlation of gamma power with age (r = -.59; p<0.01) detected in controls (2–5 yrs. vs. 6–9 yrs.) was lost in RTT. Poor % SWS (i.e., time spent in SWS overnight) in RTT was also driven by the younger age-group. Incidence of seizures in RTT was associated with significantly lower number of SWS cycles. Therefore, qEEG biomarkers of SWS in RTT evolved temporally and correlated significantly with clinical severity.
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Affiliation(s)
- Simon Ammanuel
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America; Department of Biomedical Engineering, Whiting School of Engineering,Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Wesley C Chan
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America; Department of Biomedical Engineering, Whiting School of Engineering,Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Daniel A Adler
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America; Department of Biomedical Engineering, Whiting School of Engineering,Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Balaji M Lakshamanan
- Department of Neurology and Developmental Medicine, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America
| | - Siddharth S Gupta
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Joshua B Ewen
- Department of Neurology and Developmental Medicine, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Michael V Johnston
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Carole L Marcus
- Sleep Center, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Sakkubai Naidu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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24
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Li Q, Loh DH, Kudo T, Truong D, Derakhshesh M, Kaswan ZM, Ghiani CA, Tsoa R, Cheng Y, Sun YE, Colwell CS. Circadian rhythm disruption in a mouse model of Rett syndrome circadian disruption in RTT. Neurobiol Dis 2015; 77:155-64. [PMID: 25779967 DOI: 10.1016/j.nbd.2015.03.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 03/08/2015] [Accepted: 03/09/2015] [Indexed: 12/14/2022] Open
Abstract
Disturbances in the sleep/wake cycle are prevalent in patients with Rett syndrome (RTT). We sought to determine whether the circadian system is disrupted in a RTT model, Mecp2(-/y) mice. We found that MeCP2 mutants showed decreased strength and precision of daily rhythms of activity coupled with extremely fragmented sleep. The central circadian clock (suprachiasmatic nucleus) exhibited significant reduction in the number of neurons expressing vasoactive intestinal peptide (VIP) as well as compromised spontaneous neural activity. The molecular clockwork was disrupted both centrally in the SCN and in peripheral organs, indicating a general disorganization of the circadian system. Disruption of the molecular clockwork was observed in fibroblasts of RTT patients. Finally, MeCP2 mutant mice were vulnerable to circadian disruption as chronic jet lag accelerated mortality. Our finds suggest an integral role of MeCP2 in the circadian timing system and provides a possible mechanistic explanation for the sleep/wake distrubances observed in RTT patients. The work raises the possibility that RTT patients may benefit from a temporally structured environment.
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Affiliation(s)
- Quan Li
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA; Department of Psychiatry, University of California, Los Angeles, Box 957332, 635 S. Charles E. Young Dr, Los Angeles, CA 90095-7332, USA; Molecular, Cellular and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Dawn H Loh
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Takashi Kudo
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Danny Truong
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Matthew Derakhshesh
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Zoë MacDowell Kaswan
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Cristina A Ghiani
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Rosemarie Tsoa
- Department of Psychiatry, University of California, Los Angeles, Box 957332, 635 S. Charles E. Young Dr, Los Angeles, CA 90095-7332, USA
| | - Yin Cheng
- Department of Psychiatry, University of California, Los Angeles, Box 957332, 635 S. Charles E. Young Dr, Los Angeles, CA 90095-7332, USA
| | - Yi E Sun
- Department of Psychiatry, University of California, Los Angeles, Box 957332, 635 S. Charles E. Young Dr, Los Angeles, CA 90095-7332, USA.
| | - Christopher S Colwell
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA.
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25
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Colic S, Lang M, Wither RG, Liang Z, Eubanks JH, Bardakjian BL. Characterization of HFOs in short and long duration discharges recorded from in-vivo MeCP2-deficient mice. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:4603-6. [PMID: 25571017 DOI: 10.1109/embc.2014.6944649] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Mutations in the X-linked gene encoding methyl CpG-binding protein 2 (MeCP2) have been linked to a neurodevelopmental disorder known as Rett syndrome. The disorder is associated with a number of symptoms, of which epileptic seizures are common. In this study we examined the presence of high frequency oscillations (HFOs) and their interactions with low frequency oscillations (LFOs) during epileptiform-like discharges using intracranial electroencephalogram (iEEG) recordings from male and female Mecp2-deficient mice. The study compared differences in mean HFO power levels normalized to baseline along with LFO-HFO modulation observed in short and long duration discharges. Short duration discharges, common to both male and female Mecp2-deficient mice, showed a decrease in mean HFO power levels compared to baseline levels. During the short duration discharges the theta (7-9 Hz) LFOs were found to modulate fast ripple (350-500 Hz) HFOs predominantly in the female Mecp2-deficient mice. Long duration discharges, predominantly observed in male Mecp2-deficient mice, were found to have elevated mean power levels in the ripple (80-200 Hz) and fast ripple (350-500 Hz) frequency ranges when compared to baseline. During the long duration discharges a lower frequency range theta LFO (4-6 Hz) modulated both the ripple (80-200 Hz) and fast ripple (350-500 Hz) HFOs. These findings suggest that the long duration discharges observed in male Mecp2-deficient mice share biomarkers indicative of seizure-like activity.
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26
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Johnston MV, Ammanuel S, O'Driscoll C, Wozniak A, Naidu S, Kadam SD. Twenty-four hour quantitative-EEG and in-vivo glutamate biosensor detects activity and circadian rhythm dependent biomarkers of pathogenesis in Mecp2 null mice. Front Syst Neurosci 2014; 8:118. [PMID: 25018705 PMCID: PMC4072927 DOI: 10.3389/fnsys.2014.00118] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/02/2014] [Indexed: 11/13/2022] Open
Abstract
Mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (Mecp2) cause most cases of Rett syndrome (RTT). Currently there is no cure for RTT. Abnormal EEGs are found in 100% of RTT cases and are associated with severe sleep dysfunction, the cause of which is not well understood. Mice deficient in MeCP2 protein have been studied and characterized for their neuropathological and behavioral deficits to better understand RTT. With the goal to study the non-ictal EEG correlates in symptomatic Mecp2 KO mice (Mecp2(tm1.1Bird/y)), and determine novel EEG biomarkers of their reported progressive neurodegeneration, we used 24 h video-EEG/EMG with synchronous in-vivo cortical glutamate biosensor in the frontal cortex. We scored the EEG for activity states and spectral analysis was performed to evaluate correlations to the synchronous extracellular glutamate fluctuations underlying Mecp2 inactivation as compared to WT. Significant alterations in sleep structure due to dark cycle-specific long wake states and poor quality of slow-wave sleep were associated with a significant increase in glutamate loads per activity cycle. The dynamics of the activity-state-dependent physiological rise and fall of glutamate indicative of glutamate homeostasis were significantly altered in the KO mice. Colorimetric quantitation of absolute glutamate levels in frontal cortex also indicated the presence of significantly higher levels in KO. This study for the first time found evidence of uncompensated sleep deprivation-like EEG biomarkers that were associated with glutamate homeostatic dysfunction in the Mecp2 KO mice.
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Affiliation(s)
- Michael V Johnston
- Neuroscience Laboratory, Departments of Neurology and Pediatrics, Hugo Moser Research Institute at Kennedy Krieger, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Simon Ammanuel
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger Baltimore, MD, USA
| | - Cliona O'Driscoll
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Hugo Moser Research Institute at Kennedy Krieger, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Amy Wozniak
- Biostatistics Center, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Sakkubai Naidu
- Departments of Neurology and Pediatrics, Hugo Moser Research Institute at Kennedy Krieger Baltimore, MD, USA
| | - Shilpa D Kadam
- Neuroscience Laboratory, Departments of Neurology, Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins University School of Medicine Baltimore, MD, USA
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27
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Abstract
The circadian clock choreographs fundamental biological rhythms. This system is comprised of the master circadian pacemaker in the suprachiasmatic nucleus and associated pacemakers in other tissues that coordinate complex physiological processes and behaviors, such as sleep, feeding, and metabolism. The molecular circuitry that underlies these clocks and orchestrates circadian gene expression has been the focus of intensive investigation, and it is becoming clear that epigenetic factors are highly integrated into these networks. In this review, we draw attention to the fundamental roles played by epigenetic mechanisms in transcriptional and post-transcriptional regulation within the circadian clock system. We also highlight how alterations in epigenetic factors and mechanisms are being linked with sleep-wake disorders. These observations provide important insights into the pathogenesis and potential treatment of these disorders and implicate epigenetic deregulation in the significant but poorly understood interconnections now emerging between circadian processes and neurodegeneration, metabolic diseases, cancer, and aging.
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Affiliation(s)
- Irfan A. Qureshi
- Roslyn and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Rose F. Kennedy Center for Research on Intellectual and Developmental Disabilities, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Mark F. Mehler
- Roslyn and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Rose F. Kennedy Center for Research on Intellectual and Developmental Disabilities, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Ruth S. and David L. Gottesman Stem Cell Institute, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Center for Epigenomics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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28
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Lang M, Wither RG, Colic S, Wu C, Monnier PP, Bardakjian BL, Zhang L, Eubanks JH. Rescue of behavioral and EEG deficits in male and female Mecp2-deficient mice by delayed Mecp2 gene reactivation. Hum Mol Genet 2013; 23:303-18. [PMID: 24009314 PMCID: PMC3869352 DOI: 10.1093/hmg/ddt421] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mutations of the X-linked gene encoding methyl CpG binding protein type 2 (MECP2) are the predominant cause of Rett syndrome, a severe neurodevelopmental condition that affects primarily females. Previous studies have shown that major phenotypic deficits arising from MeCP2-deficiency may be reversible, as the delayed reactivation of the Mecp2 gene in Mecp2-deficient mice improved aspects of their Rett-like phenotype. While encouraging for prospective gene replacement treatments, it remains unclear whether additional Rett syndrome co-morbidities recapitulated in Mecp2-deficient mice will be similarly responsive to the delayed reintroduction of functional Mecp2. Here, we show that the delayed reactivation of Mecp2 in both male and female Mecp2-deficient mice rescues established deficits in motor and anxiety-like behavior, epileptiform activity, cortical and hippocampal electroencephalogram patterning and thermoregulation. These findings indicate that neural circuitry deficits arising from the deficiency in Mecp2 are not engrained, and provide further evidence that delayed restoration of Mecp2 function can improve a wide spectrum of the Rett-like deficits recapitulated by Mecp2-deficient mice.
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Affiliation(s)
- Min Lang
- Division of Genetics and Development and
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29
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Colic S, Wither RG, Zhang L, Eubanks JH, Bardakjian BL. Characterization of seizure-like events recorded in vivo in a mouse model of Rett syndrome. Neural Netw 2013; 46:109-15. [PMID: 23727441 DOI: 10.1016/j.neunet.2013.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 05/01/2013] [Accepted: 05/05/2013] [Indexed: 10/26/2022]
Abstract
Rett syndrome is a neurodevelopmental disorder caused by mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MECP2). Spontaneous recurrent discharge episodes are displayed in Rett-related seizures as in other types of epilepsies. The aim of this paper is to investigate the seizure-like event (SLE) and inter-SLE states in a female MeCP2-deficient mouse model of Rett syndrome and compare them to those found in other spontaneous recurrent epilepsy models. The study was performed on a small population of female MeCP2-deficient mice using telemetric local field potential (LFP) recordings over a 24 h period. Durations of SLEs and inter-SLEs were extracted using a rule-based automated SLE detection system for both daytime and nighttime, as well as high and low power levels of the delta frequency range (0.5-4 Hz) of the recorded LFPs. The results suggest SLE occurrences are not influenced by circadian rhythms, but had a significantly greater association with delta power. Investigating inter-SLE and SLE states by fitting duration histograms to the gamma distribution showed that SLE initiation and termination were associated with random and deterministic mechanisms, respectively. These findings when compared to reported studies on epilepsy suggest that Rett-related seizures share many similarities with absence epilepsy.
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Affiliation(s)
- Sinisa Colic
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada.
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30
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Katz DM, Berger-Sweeney JE, Eubanks JH, Justice MJ, Neul JL, Pozzo-Miller L, Blue ME, Christian D, Crawley JN, Giustetto M, Guy J, Howell CJ, Kron M, Nelson SB, Samaco RC, Schaevitz LR, St Hillaire-Clarke C, Young JL, Zoghbi HY, Mamounas LA. Preclinical research in Rett syndrome: setting the foundation for translational success. Dis Model Mech 2013; 5:733-45. [PMID: 23115203 PMCID: PMC3484856 DOI: 10.1242/dmm.011007] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In September of 2011, the National Institute of Neurological Disorders and Stroke (NINDS), the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the International Rett Syndrome Foundation (IRSF) and the Rett Syndrome Research Trust (RSRT) convened a workshop involving a broad cross-section of basic scientists, clinicians and representatives from the National Institutes of Health (NIH), the US Food and Drug Administration (FDA), the pharmaceutical industry and private foundations to assess the state of the art in animal studies of Rett syndrome (RTT). The aim of the workshop was to identify crucial knowledge gaps and to suggest scientific priorities and best practices for the use of animal models in preclinical evaluation of potential new RTT therapeutics. This review summarizes outcomes from the workshop and extensive follow-up discussions among participants, and includes: (1) a comprehensive summary of the physiological and behavioral phenotypes of RTT mouse models to date, and areas in which further phenotypic analyses are required to enhance the utility of these models for translational studies; (2) discussion of the impact of genetic differences among mouse models, and methodological differences among laboratories, on the expression and analysis, respectively, of phenotypic traits; and (3) definitions of the standards that the community of RTT researchers can implement for rigorous preclinical study design and transparent reporting to ensure that decisions to initiate costly clinical trials are grounded in reliable preclinical data.
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Affiliation(s)
- David M Katz
- Department of Neurosciences, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44120, USA.
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31
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Hippocampal excitability is increased in aged mice. Exp Neurol 2013; 247:710-9. [PMID: 23510762 DOI: 10.1016/j.expneurol.2013.03.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 03/05/2013] [Accepted: 03/08/2013] [Indexed: 12/22/2022]
Abstract
Aging is known to be associated with a high risk of developing seizure disorders. Currently, the mechanisms underlying this increased seizure susceptibility are not fully understood. Several previous studies have shown a loss of subgroups of GABAergic inhibitory interneurons in the hippocampus of aged rodents, yet the network excitability intrinsic to the aged hippocampus remains to be elucidated. The aim of this study is to examine age-dependent changes of hippocampal network activities in young adult (3-5 months), aging (16-18 months), and aged (24-28 months) mice. We conducted intracranial electroencephalographic (EEG) recordings in free-moving animals and extracellular recordings in hippocampal slices in vitro. EEG recordings revealed frequent spikes in aging and aged mice but only occasionally in young adults. These EEG spikes were suppressed following diazepam administration. Spontaneous field potentials with large amplitudes were frequently observed in hippocampal slices of aged mice but rarely in slices from young adults. These spontaneous field potentials originated from the CA3 area and their generation was dependent upon the excitatory glutamatergic activity. We therefore postulate that hippocampal network excitability is increased in aged mice and that such hyperactivity may be relevant to the increased seizure susceptibility observed in aged subjects.
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32
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Colic S, Lang M, Wither RG, Eubanks JH, Liang Z, Bardakjian BL. Low frequency-modulated high frequency oscillations in seizure-like events recorded from in-vivo MeCP2-deficient mice. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:985-988. [PMID: 24109855 DOI: 10.1109/embc.2013.6609668] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Rett syndrome is a neurodevelopmental condition caused by mutations in the gene encoding methyl CpG-binding protein 2 (MeCP2). Seizures are often associated with Rett syndrome and can be observed in intracranial electroencephalogram (iEEG) recordings. To date most studies have focused on the low frequencies oscillations (LFOs), however recent findings in epilepsy studies link high frequency oscillations (HFOs) with epileptogenesis. In this study, we examine the presence of HFOs in the male and female MeCP2-deficient mouse models of Rett syndrome and their interaction with the LFOs present during seizure-like events (SLEs). Our findings indicate that HFOs (200-600 Hz) are present during the SLEs and in addition, we reveal strong phase-amplitude coupling between LFOs (6-10 Hz) and HFOs (200-600 Hz) during female SLEs in the MeCP2-deficient mouse model.
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33
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Wither RG, Lang M, Zhang L, Eubanks JH. Regional MeCP2 expression levels in the female MeCP2-deficient mouse brain correlate with specific behavioral impairments. Exp Neurol 2013; 239:49-59. [DOI: 10.1016/j.expneurol.2012.09.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 09/13/2012] [Accepted: 09/20/2012] [Indexed: 11/25/2022]
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34
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Lang M, Wither RG, Brotchie JM, Wu C, Zhang L, Eubanks JH. Selective preservation of MeCP2 in catecholaminergic cells is sufficient to improve the behavioral phenotype of male and female Mecp2-deficient mice. Hum Mol Genet 2012; 22:358-71. [PMID: 23077217 DOI: 10.1093/hmg/dds433] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused primarily by mutations of the X-linked MECP2 gene. Although the loss of MeCP2 function affects many neural systems, impairments of catecholaminergic function have been hypothesized to underlie several of the cardinal behavioral deficits of RTT patients and Mecp2-deficient mice. Although recent Mecp2 reactivation studies indicate that RTT may be a reversible condition, it remains unclear whether specifically preserving Mecp2 function within a specific system will be sufficient to convey beneficial effects. Here, we test whether the selective preservation of Mecp2 within catecholaminergic cells will improve the phenotype of Mecp2-deficient mice. Our results show that this targeted preservation of Mecp2 significantly improves the lifespan, phenotypic severity and cortical epileptiform discharge activity of both male and female Mecp2-deficient mice. Further, we found that the catecholaminergic preservation of Mecp2 also improves the ambulatory rate, rearing activity, motor coordination, anxiety and nest-building performances of Mecp2-deficient mice of each gender. Interestingly, our results also revealed a gender-specific improvement, as specific cortical and hippocampal electroencephalographic abnormalities were significantly improved in male, but not female, rescue mice. Collectively, these results support the role of the catecholaminergic system in the pathogenesis of RTT and provide proof-of-principle that restoring MeCP2 function within this specific system could represent a treatment strategy for RTT.
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Affiliation(s)
- Min Lang
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, 399 Bathurst Street, Toronto, ON, Canada M5T 2S8
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