101
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Shanmugapriya S, Bhavani P, Subramanian P. Effect of geraniol on temporal patterns of clock gene products during endometrial carcinogenesis in rats. BIOL RHYTHM RES 2016. [DOI: 10.1080/09291016.2016.1144500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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102
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Sleep-Wake Regulation and Its Impact on Working Memory Performance: The Role of Adenosine. BIOLOGY 2016; 5:biology5010011. [PMID: 26861410 PMCID: PMC4810168 DOI: 10.3390/biology5010011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 01/15/2016] [Accepted: 01/19/2016] [Indexed: 11/28/2022]
Abstract
The sleep-wake cycle is regulated by a fine-tuned interplay between sleep-homeostatic and circadian mechanisms. Compelling evidence suggests that adenosine plays an important role in mediating the increase of homeostatic sleep pressure during time spent awake and its decrease during sleep. Here, we summarize evidence that adenosinergic mechanisms regulate not only the dynamic of sleep pressure, but are also implicated in the interaction of homeostatic and circadian processes. We review how this interaction becomes evident at several levels, including electrophysiological data, neuroimaging studies and behavioral observations. Regarding complex human behavior, we particularly focus on sleep-wake regulatory influences on working memory performance and underlying brain activity, with a specific emphasis on the role of adenosine in this interplay. We conclude that a change in adenosinergic mechanisms, whether exogenous or endogenous, does not only impact on sleep-homeostatic processes, but also interferes with the circadian timing system.
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103
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Sunagawa G, Sumiyama K, Ukai-Tadenuma M, Perrin D, Fujishima H, Ukai H, Nishimura O, Shi S, Ohno RI, Narumi R, Shimizu Y, Tone D, Ode K, Kuraku S, Ueda H. Mammalian Reverse Genetics without Crossing Reveals Nr3a as a Short-Sleeper Gene. Cell Rep 2016; 14:662-677. [DOI: 10.1016/j.celrep.2015.12.052] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 10/29/2015] [Accepted: 12/08/2015] [Indexed: 11/24/2022] Open
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104
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Abstract
Cortical electroencephalographic activity arises from corticothalamocortical interactions, modulated by wake-promoting monoaminergic and cholinergic input. These wake-promoting systems are regulated by hypothalamic hypocretin/orexins, while GABAergic sleep-promoting nuclei are found in the preoptic area, brainstem and lateral hypothalamus. Although pontine acetylcholine is critical for REM sleep, hypothalamic melanin-concentrating hormone/GABAergic cells may "gate" REM sleep. Daily sleep-wake rhythms arise from interactions between a hypothalamic circadian pacemaker and a sleep homeostat whose anatomical locus has yet to be conclusively defined. Control of sleep and wakefulness involves multiple systems, each of which presents vulnerability to sleep/wake dysfunction that may predispose to physical and/or neuropsychiatric disorders.
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Affiliation(s)
- Michael D Schwartz
- Biosciences Division, Center for Neuroscience, SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA
| | - Thomas S Kilduff
- Biosciences Division, Center for Neuroscience, SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA.
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105
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The bipolarity of light and dark: A review on Bipolar Disorder and circadian cycles. J Affect Disord 2015; 185:219-29. [PMID: 26241867 DOI: 10.1016/j.jad.2015.07.017] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/06/2015] [Accepted: 07/08/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND Bipolar Disorder is characterized by episodes running the full mood spectrum, from mania to depression. Between mood episodes, residual symptoms remain, as sleep alterations, circadian cycle disturbances, emotional deregulation, cognitive impairment and increased risk for comorbidities. The present review intends to reflect about the most recent and relevant information concerning the biunivocal relation between bipolar disorder and circadian cycles. METHODS It was conducted a literature search on PubMed database using the search terms "bipolar", "circadian", "melatonin", "cortisol", "body temperature", "Clock gene", "Bmal1 gene", "Per gene", "Cry gene", "GSK3β", "chronotype", "light therapy", "dark therapy", "sleep deprivation", "lithum" and "agomelatine". Search results were manually reviewed, and pertinent studies were selected for inclusion as appropriate. RESULTS Several studies support the relationship between bipolar disorder and circadian cycles, discussing alterations in melatonin, body temperature and cortisol rhythms; disruption of sleep/wake cycle; variations of clock genes; and chronotype. Some therapeutics for bipolar disorder directed to the circadian cycles disturbances are also discussed, including lithium carbonate, agomelatine, light therapy, dark therapy, sleep deprivation and interpersonal and social rhythm therapy. LIMITATIONS This review provides a summary of an extensive research for the relevant literature on this theme, not a patient-wise meta-analysis. CONCLUSIONS In the future, it is essential to achieve a better understanding of the relation between bipolar disorder and the circadian system. It is required to establish new treatment protocols, combining psychotherapy, therapies targeting the circadian rhythms and the latest drugs, in order to reduce the risk of relapse and improve affective behaviour.
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106
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Curie T, Maret S, Emmenegger Y, Franken P. In Vivo Imaging of the Central and Peripheral Effects of Sleep Deprivation and Suprachiasmatic Nuclei Lesion on PERIOD-2 Protein in Mice. Sleep 2015; 38:1381-94. [PMID: 25581923 DOI: 10.5665/sleep.4974] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/09/2014] [Indexed: 01/20/2023] Open
Abstract
STUDY OBJECTIVES That sleep deprivation increases the brain expression of various clock genes has been well documented. Based on these and other findings we hypothesized that clock genes not only underlie circadian rhythm generation but are also implicated in sleep homeostasis. However, long time lags have been reported between the changes in the clock gene messenger RNA levels and their encoded proteins. It is therefore crucial to establish whether also protein levels increase within the time frame known to activate a homeostatic sleep response. We report on the central and peripheral effects of sleep deprivation on PERIOD-2 (PER2) protein both in intact and suprachiasmatic nuclei-lesioned mice. DESIGN In vivo and in situ PER2 imaging during baseline, sleep deprivation, and recovery. SETTINGS Mouse sleep-recording facility. PARTICIPANTS Per2::Luciferase knock-in mice. INTERVENTIONS N/A. MEASUREMENTS AND RESULTS Six-hour sleep deprivation increased PER2 not only in the brain but also in liver and kidney. Remarkably, the effects in the liver outlasted those observed in the brain. Within the brain the increase in PER2 concerned the cerebral cortex mainly, while leaving suprachiasmatic nuclei (SCN) levels unaffected. Against expectation, sleep deprivation did not increase PER2 in the brain of arrhythmic SCN-lesioned mice because of higher PER2 levels in baseline. In contrast, liver PER2 levels did increase in these mice similar to the sham and partially lesioned controls. CONCLUSIONS Our results stress the importance of considering both sleep-wake dependent and circadian processes when quantifying clock-gene levels. Because sleep deprivation alters PERIOD-2 in the brain as well as in the periphery, it is tempting to speculate that clock genes constitute a common pathway mediating the shared and well-known adverse effects of both chronic sleep loss and disrupted circadian rhythmicity on metabolic health.
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Affiliation(s)
- Thomas Curie
- Center for Integrative Genomics, University of Lausanne, Switzerland
| | - Stephanie Maret
- Center for Integrative Genomics, University of Lausanne, Switzerland
| | - Yann Emmenegger
- Center for Integrative Genomics, University of Lausanne, Switzerland
| | - Paul Franken
- Center for Integrative Genomics, University of Lausanne, Switzerland
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107
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Takeda N, Maemura K. The role of clock genes and circadian rhythm in the development of cardiovascular diseases. Cell Mol Life Sci 2015; 72:3225-34. [PMID: 25972277 PMCID: PMC11113935 DOI: 10.1007/s00018-015-1923-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 05/04/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
Abstract
The time of onset of cardiovascular disorders such as myocardial infarctions or ventricular arrhythmias exhibits a circadian rhythm. Diurnal variations in autonomic nervous activity, plasma cortisol level or renin-angiotensin activity underlie the pathogenesis of cardiovascular diseases. Transcriptional-translational feedback loop of the clock genes constitute a molecular clock system. In addition to the central clock in the suprachiasmatic nucleus, clock genes are also expressed in a circadian fashion in each organ to make up the peripheral clock. The peripheral clock seems to be beneficial for anticipating external stimuli and thus contributes to the maintenance of organ homeostasis. Loss of synchronization between the central and peripheral clocks also augments disease progression. Moreover, accumulating evidence shows that clock genes affect inflammatory and intracellular metabolic signaling. Elucidating the roles of the molecular clock in cardiovascular pathology through the identification of clock controlled genes will help to establish a novel therapeutic approach for cardiovascular disorders.
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Affiliation(s)
- Norihiko Takeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Koji Maemura
- Department of Cardiovascular Medicine, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501 Japan
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108
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Phillips DJ, Savenkova MI, Karatsoreos IN. Environmental disruption of the circadian clock leads to altered sleep and immune responses in mouse. Brain Behav Immun 2015; 47:14-23. [PMID: 25542734 DOI: 10.1016/j.bbi.2014.12.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/26/2014] [Accepted: 12/05/2014] [Indexed: 12/29/2022] Open
Abstract
In mammals, one of the most salient outputs of the circadian (daily) clock is the timing of the sleep-wake cycle. Modern industrialized society has led to a fundamental breakdown in the relationship between our endogenous timekeeping systems and the solar day, disrupting normal circadian rhythms. We have argued that disrupted circadian rhythms could lead to changes in allostatic load, and the capacity of organisms to respond to other environmental challenges. In this set of studies, we apply a model of circadian disruption characterized in our lab in which mice are housed in a 20h long day, with 10h of light and 10h of darkness. We explored the effects of this environmental disruption on sleep patterns, to establish if this model results in marked sleep deprivation. Given the interaction between circadian, sleep, and immune systems, we further probed if our model of circadian disruption also alters the innate immune response to peripheral bacterial endotoxin challenge. Our results demonstrate that this model of circadian disruption does not lead to marked sleep deprivation, but instead affects the timing and quality of sleep. We also show that while circadian disruption does not lead to basal changes in the immune markers we explored, the immune response is affected, both in the brain and the periphery. Together, our findings further strengthen the important role of the circadian timing system in sleep regulation and immune responses, and provide evidence that disrupting the circadian clock increases vulnerability to further environmental stressors, including immunological challenges.
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Affiliation(s)
- Derrick J Phillips
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA
| | - Marina I Savenkova
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA
| | - Ilia N Karatsoreos
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA.
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109
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Zordan MA, Sandrelli F. Circadian Clock Dysfunction and Psychiatric Disease: Could Fruit Flies have a Say? Front Neurol 2015; 6:80. [PMID: 25941512 PMCID: PMC4403521 DOI: 10.3389/fneur.2015.00080] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/24/2015] [Indexed: 12/15/2022] Open
Abstract
There is evidence of a link between the circadian system and psychiatric diseases. Studies in humans and mammals suggest that environmental and/or genetic disruption of the circadian system leads to an increased liability to psychiatric disease. Disruption of clock genes and/or the clock network might be related to the etiology of these pathologies; also, some genes, known for their circadian clock functions, might be associated to mental illnesses through clock-independent pleiotropy. Here, we examine the features which we believe make Drosophila melanogaster a model apt to study the role of the circadian clock in psychiatric disease. Despite differences in the organization of the clock system, the molecular architecture of the Drosophila and mammalian circadian oscillators are comparable and many components are evolutionarily related. In addition, Drosophila has a rather complex nervous system, which shares much at the cell and neurobiological level with humans, i.e., a tripartite brain, the main neurotransmitter systems, and behavioral traits: circadian behavior, learning and memory, motivation, addiction, social behavior. There is evidence that the Drosophila brain shares some homologies with the vertebrate cerebellum, basal ganglia, and hypothalamus-pituitary-adrenal axis, the dysfunctions of which have been tied to mental illness. We discuss Drosophila in comparison to mammals with reference to the: organization of the brain and neurotransmitter systems; architecture of the circadian clock; clock-controlled behaviors. We sum up current knowledge on behavioral endophenotypes, which are amenable to modeling in flies, such as defects involving sleep, cognition, or social interactions, and discuss the relationship of the circadian system to these traits. Finally, we consider if Drosophila could be a valuable asset to understand the relationship between circadian clock malfunction and psychiatric disease.
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Affiliation(s)
- Mauro Agostino Zordan
- Department of Biology, University of Padova, Padova, Italy
- Cognitive Neuroscience Center, University of Padova, Padova, Italy
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110
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Tasaki H, Zhao L, Isayama K, Chen H, Yamauchi N, Shigeyoshi Y, Hashimoto S, Hattori MA. Inhibitory role of REV-ERBα in the expression of bone morphogenetic protein gene family in rat uterus endometrium stromal cells. Am J Physiol Cell Physiol 2015; 308:C528-38. [DOI: 10.1152/ajpcell.00220.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 01/05/2015] [Indexed: 11/22/2022]
Abstract
Uterus circadian rhythms have been implicated in the gestation processes of mammals through entraining of the clock proteins to numerous downstream genes. Bone morphogenetic proteins (BMPs), having clock-controlled regulatory sites in their gene promoters, are expressed in the uterus during decidualization, but the regulation of the Bmp gene expression is poorly understood. The present study was designed to dissect the physiological roles of the uterus oscillators in the Bmp expression using the uterus endometrial stromal cells (UESCs) isolated from Per2-dLuc transgenic rats on day 4.5 of gestation. The in vitro decidualization of UESCs was induced by medroxyprogesterone acetate and 2-O-dibutyryl cAMP. A significant decline of Per2-dLuc bioluminescence activity was induced in decidual cells, and concomitantly, the expression of canonical clock genes was downregulated. Conversely, the expression of the core Bmp genes Bmp2, Bmp4, Bmp6, and Bmp7 was upregulated. In UESCs transfected with Bmal1-specific siRNA, in which Rev-erbα expression was downregulated, Bmp genes, such as Bmp2, Bmp4, and Bmp6 were upregulated. However, Bmp1, Bmp7, and Bmp8a were not significantly affected by Bmal1 silencing. The expression of all Bmp genes was enhanced after treatment with the REV-ERBα antagonist (SR8278), although their rhythmic profiles were differed from each other. The binding of REV-ERBα to the proximal regions of the Bmp2 and Bmp4 promoters was revealed by chromatin immunoprecipitation-PCR analysis. Collectively, these results indicate that the Bmp genes are upregulated by the attenuation of the cellular circadian clock; in particular, its core component REV-ERBα functions as a transcriptional silencer in the Bmp gene family.
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Affiliation(s)
- Hirotaka Tasaki
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Lijia Zhao
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Keishiro Isayama
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Huatao Chen
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Nobuhiko Yamauchi
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Yasufumi Shigeyoshi
- Department of Anatomy and Neurobiology, Kinki University School of Medicine, Osaka, Japan; and
| | | | - Masa-aki Hattori
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
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111
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Sleep, circadian rhythms, and the pathogenesis of Alzheimer disease. Exp Mol Med 2015; 47:e148. [PMID: 25766617 PMCID: PMC4351409 DOI: 10.1038/emm.2014.121] [Citation(s) in RCA: 326] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 11/19/2014] [Indexed: 01/16/2023] Open
Abstract
Disturbances in the sleep–wake cycle and circadian rhythms are common symptoms of Alzheimer Disease (AD), and they have generally been considered as late consequences of the neurodegenerative processes. Recent evidence demonstrates that sleep–wake and circadian disruption often occur early in the course of the disease and may even precede the development of cognitive symptoms. Furthermore, the sleep–wake cycle appears to regulate levels of the pathogenic amyloid-beta peptide in the brain, and manipulating sleep can influence AD-related pathology in mouse models via multiple mechanisms. Finally, the circadian clock system, which controls the sleep–wake cycle and other diurnal oscillations in mice and humans, may also have a role in the neurodegenerative process. In this review, we examine the current literature related to the mechanisms by which sleep and circadian rhythms might impact AD pathogenesis, and we discuss potential therapeutic strategies targeting these systems for the prevention of AD.
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112
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Glutamate-Dependent BMAL1 Regulation in Cultured Bergmann Glia Cells. Neurochem Res 2015; 40:961-70. [PMID: 25749891 DOI: 10.1007/s11064-015-1551-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/25/2015] [Accepted: 03/02/2015] [Indexed: 10/23/2022]
Abstract
Glutamate, the major excitatory amino acid, activates a wide variety of signal transduction cascades. This neurotransmitter is involved in photic entrainment of circadian rhythms, which regulate physiological and behavioral functions. The circadian clock in vertebrates is based on a transcription-translation feedback loop in which Brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like protein 1 (BMAL1) acts as transcriptional activator of others clock genes. This protein is expressed in nearly all suprachiasmatic nucleus neurons, as well as in the granular layer of the cerebellum. In this context, we decided to investigate the role of glutamate in the molecular mechanisms involved in the processes of transcription/translation of BMAL1 protein. To this end, primary cultures of chick cerebellar Bergmann glial cells were stimulated with glutamatergic ligands and we found that BMAL1 levels increased in a dose- and time dependent manner. Additionally, we studied the phosphorylation of serine residues in BMAL1 under glutamate stimulation and we were able to detect an increase in the phosphorylation of this protein. The increased expression of BMAL1 is most probably the result of a stabilization of the protein after it has been phosphorylated by the cyclic AMP-dependent protein kinase and/or the Ca(2+)/diacylglycerol dependent protein kinase. The present results strongly suggest that glutamate participates in regulating BMAL1 in glial cells and that these cells might prove to be important in the control of circadian rhythms in the cerebellum.
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113
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Musiek ES. Circadian clock disruption in neurodegenerative diseases: cause and effect? Front Pharmacol 2015; 6:29. [PMID: 25774133 PMCID: PMC4343016 DOI: 10.3389/fphar.2015.00029] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 02/03/2015] [Indexed: 12/19/2022] Open
Abstract
Disturbance of the circadian system, manifested as disrupted daily rhythms of physiologic parameters such as sleep, activity, and hormone secretion, has long been observed as a symptom of several neurodegenerative diseases, including Alzheimer disease. Circadian abnormalities have generally been considered consequences of the neurodegeneration. Recent evidence suggests, however, that circadian disruption might actually contribute to the neurodegenerative process, and thus might be a modifiable cause of neural injury. Herein we will review the evidence implicating circadian rhythms disturbances and clock gene dysfunction in neurodegeneration, with an emphasis on future research directions and potential therapeutic implications for neurodegenerative diseases.
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Affiliation(s)
- Erik S Musiek
- Hope Center for Neurological Disorders and Charles F. and Joanne Knight Alzheimer's Disease Research Center, Department of Neurology, Washington University School of Medicine in St. Louis , Saint Louis, MO, USA
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114
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Abstract
Sleep is a complex behavior both in its manifestation and regulation, that is common to almost all animal species studied thus far. Sleep is not a unitary behavior and has many different aspects, each of which is tightly regulated and influenced by both genetic and environmental factors. Despite its essential role for performance, health, and well-being, genetic mechanisms underlying this complex behavior remain poorly understood. One important aspect of sleep concerns its homeostatic regulation, which ensures that levels of sleep need are kept within a range still allowing optimal functioning during wakefulness. Uncovering the genetic pathways underlying the homeostatic aspect of sleep is of particular importance because it could lead to insights concerning sleep's still elusive function and is therefore a main focus of current sleep research. In this chapter, we first give a definition of sleep homeostasis and describe the molecular genetics techniques that are used to examine it. We then provide a conceptual discussion on the problem of assessing a sleep homeostatic phenotype in various animal models. We finally highlight some of the studies with a focus on clock genes and adenosine signaling molecules.
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Affiliation(s)
- Géraldine M Mang
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015, Lausanne-Dorigny, Switzerland,
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115
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Banerjee S, Wang Y, Solt LA, Griffett K, Kazantzis M, Amador A, El-Gendy BM, Huitron-Resendiz S, Roberts AJ, Shin Y, Kamenecka TM, Burris TP. Pharmacological targeting of the mammalian clock regulates sleep architecture and emotional behaviour. Nat Commun 2014; 5:5759. [PMID: 25536025 PMCID: PMC4495958 DOI: 10.1038/ncomms6759] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 11/04/2014] [Indexed: 12/20/2022] Open
Abstract
Synthetic drug-like molecules that directly modulate the activity of key clock proteins offer the potential to directly modulate the endogenous circadian rhythm and treat diseases associated with clock dysfunction. Here we demonstrate that synthetic ligands targeting a key component of the mammalian clock, the nuclear receptors REV-ERBα and β, regulate sleep architecture and emotional behaviour in mice. REV-ERB agonists induce wakefulness and reduce REM and slow-wave sleep. Interestingly, REV-ERB agonists also reduce anxiety-like behaviour. These data are consistent with increased anxiety-like behaviour of REV-ERBβ-null mice, in which REV-ERB agonists have no effect. These results indicate that pharmacological targeting of REV-ERB may lead to the development of novel therapeutics to treat sleep disorders and anxiety.
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MESH Headings
- ARNTL Transcription Factors/genetics
- ARNTL Transcription Factors/metabolism
- Animals
- Anxiety/drug therapy
- Anxiety/genetics
- Anxiety/metabolism
- Anxiety/physiopathology
- Behavior, Animal/drug effects
- CLOCK Proteins/genetics
- CLOCK Proteins/metabolism
- Circadian Clocks/drug effects
- Circadian Clocks/genetics
- Circadian Rhythm/genetics
- Cryptochromes/genetics
- Cryptochromes/metabolism
- Feedback, Physiological
- Gene Expression Regulation
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Nuclear Receptor Subfamily 1, Group D, Member 1/genetics
- Nuclear Receptor Subfamily 1, Group D, Member 1/metabolism
- Period Circadian Proteins/genetics
- Period Circadian Proteins/metabolism
- Pyrrolidines/pharmacology
- Receptors, Cytoplasmic and Nuclear/agonists
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Repressor Proteins/agonists
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Reward
- Signal Transduction
- Sleep, REM/drug effects
- Thiophenes/pharmacology
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Affiliation(s)
- Subhashis Banerjee
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter FL 33458
| | - Yongjun Wang
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104
| | - Laura A. Solt
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter FL 33458
| | - Kristine Griffett
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104
| | - Melissa Kazantzis
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter FL 33458
| | - Ariadna Amador
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter FL 33458
| | - Bahaa M. El-Gendy
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter FL 33458
| | - Salvador Huitron-Resendiz
- Department of Molecular and Integrative Neurosciences, The Scripps Research Institute, La Jolla, CA 92037
| | - Amanda J. Roberts
- Department of Molecular and Integrative Neurosciences, The Scripps Research Institute, La Jolla, CA 92037
| | - Youseung Shin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter FL 33458
| | - Theodore M. Kamenecka
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter FL 33458
| | - Thomas P. Burris
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104
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116
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Yu X, Zecharia A, Zhang Z, Yang Q, Yustos R, Jager P, Vyssotski AL, Maywood ES, Chesham JE, Ma Y, Brickley SG, Hastings MH, Franks NP, Wisden W. Circadian factor BMAL1 in histaminergic neurons regulates sleep architecture. Curr Biol 2014; 24:2838-44. [PMID: 25454592 PMCID: PMC4252164 DOI: 10.1016/j.cub.2014.10.019] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 08/29/2014] [Accepted: 10/08/2014] [Indexed: 12/24/2022]
Abstract
Circadian clocks allow anticipation of daily environmental changes. The suprachiasmatic nucleus (SCN) houses the master clock, but clocks are also widely expressed elsewhere in the body. Although some peripheral clocks have established roles, it is unclear what local brain clocks do. We tested the contribution of one putative local clock in mouse histaminergic neurons in the tuberomamillary nucleus to the regulation of the sleep-wake cycle. Histaminergic neurons are silent during sleep, and start firing after wake onset; the released histamine, made by the enzyme histidine decarboxylase (HDC), enhances wakefulness. We found that hdc gene expression varies with time of day. Selectively deleting the Bmal1 (also known as Arntl or Mop3) clock gene from histaminergic cells removes this variation, producing higher HDC expression and brain histamine levels during the day. The consequences include more fragmented sleep, prolonged wake at night, shallower sleep depth (lower nonrapid eye movement [NREM] δ power), increased NREM-to-REM transitions, hindered recovery sleep after sleep deprivation, and impaired memory. Removing BMAL1 from histaminergic neurons does not, however, affect circadian rhythms. We propose that for mammals with polyphasic/nonwake consolidating sleep, the local BMAL1-dependent clock directs appropriately timed declines and increases in histamine biosynthesis to produce an appropriate balance of wake and sleep within the overall daily cycle of rest and activity specified by the SCN.
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Affiliation(s)
- Xiao Yu
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK
| | - Anna Zecharia
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK
| | - Zhe Zhang
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK
| | - Qianzi Yang
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK
| | - Raquel Yustos
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK
| | - Polona Jager
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Winterhurerstrasse 190, Zurich 8057, Switzerland
| | - Elizabeth S Maywood
- Neurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Johanna E Chesham
- Neurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Ying Ma
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK
| | - Stephen G Brickley
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK
| | - Michael H Hastings
- Neurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Nicholas P Franks
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK.
| | - William Wisden
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, Exhibition Road, London SW7 2AZ, UK.
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117
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Leu HB, Chung CM, Lin SJ, Chiang KM, Yang HC, Ho HY, Ting CT, Lin TH, Sheu SH, Tsai WC, Chen JH, Yin WH, Chiu TY, Chen CI, Fann CS, Chen YT, Pan WH, Chen JW. Association of circadian genes with diurnal blood pressure changes and non-dipper essential hypertension: a genetic association with young-onset hypertension. Hypertens Res 2014; 38:155-62. [PMID: 25410879 DOI: 10.1038/hr.2014.152] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Revised: 08/01/2014] [Accepted: 08/27/2014] [Indexed: 01/17/2023]
Abstract
Recent studies have suggested that circadian genes have important roles in maintaining the circadian rhythm of the cardiovascular system. However, the associations between diurnal BP changes and circadian genes remain undetermined. We conducted a genetic association study of young-onset hypertension, in which 24-h ambulatory blood pressure (BP) monitoring was performed. A total of 23 tag single-nucleotide polymorphisms (SNPs) on 11 genes involved in circadian rhythms were genotyped for correlations with diurnal BP variation phenotypes. A permutation test was used to correct for multiple testing. Five tag SNPs within five loci, including rs3888170 in NPAS2, rs6431590 in PER2, rs1410225 in RORββ, rs3816358 in BMAL1 and rs10519096 in RORα, were significantly associated with the non-dipper phenotype in 372 young hypertensive patients. A genetic risk score was generated by counting the risk alleles and effects for each individual. Genotyping was performed in an additional independent set of 619 young-onset hypertensive subjects. Altogether, non-dippers had a higher weighted genetic risk score than dippers (1.67±0.56 vs. 1.54±0.55, P<0.001), and the additive genetic risk score also indicated a graded association with decreased diurnal BP changes (P=0.006), as well as a non-dipper phenotype (P=0.031). After multivariable logistic analysis, only the circadian genetic risk score (odds ratio (OR), 1550; 95% confidence interval (CI), 1.225-1.961, P<0.001) and the use of β-blockers (OR, 1.519; 95% CI, 1.164-1.982, P=0.003) were independently associated with the presence of non-dippers among subjects with young-onset hypertension. Genetic variants in circadian genes were associated with the diurnal phenotype of hypertension, suggesting a genetic association with diurnal BP changes in essential hypertension.
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Affiliation(s)
- Hsin-Bang Leu
- 1] Institute of Clinical Medicine and Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan [2] Heath Care and Management Center, Taipei Veterans General Hospital, Taipei, Taiwan [3] Divison of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chia-Min Chung
- 1] Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan [2] Environment-Omics-Disease Research Center, China Medical University Hospital, Taichung, Taiwan [3] Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
| | - Shing-Jong Lin
- 1] Institute of Clinical Medicine and Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan [2] Divison of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Kuang-Mao Chiang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hsin-Chou Yang
- Institute of Statistical Science, Academia Sinica, Taipei, Taiwan
| | - Hung-Yun Ho
- Taichung Veterans General Hospital, Taichung, Taiwan
| | - Chih-Tai Ting
- Taichung Veterans General Hospital, Taichung, Taiwan
| | - Tsung-Hsien Lin
- Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan
| | - Sheng-Hsiung Sheu
- Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan
| | | | - Jyh-Hong Chen
- National Cheng Kung University Hospital, Tainan, Taiwan
| | - Wei-Hsian Yin
- Cheng Hsin Rehabilitation Medical Center, Taipei, Taiwan
| | | | | | - Cathy Sj Fann
- Institute of Statistical Science, Academia Sinica, Taipei, Taiwan
| | - Yuan-Tsong Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Wen-Harn Pan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Jaw-Wen Chen
- 1] Institute of Clinical Medicine and Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan [2] Divison of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan [3] Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
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118
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Gotoh T, Vila-Caballer M, Liu J, Schiffhauer S, Finkielstein CV. Association of the circadian factor Period 2 to p53 influences p53's function in DNA-damage signaling. Mol Biol Cell 2014; 26:359-72. [PMID: 25411341 PMCID: PMC4294682 DOI: 10.1091/mbc.e14-05-0994] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Association of the circadian Per2 factor to p53 results in cytosol–nuclear shuttling of the complex and further association to Mdm2. The trimeric complex remains in the nucleus until a genotoxic signal frees p53, allowing for a transcriptional checkpoint response. Circadian period proteins influence cell division and death by associating with checkpoint components, although their mode of regulation has not been firmly established. hPer2 forms a trimeric complex with hp53 and its negative regulator Mdm2. In unstressed cells, this association leads to increased hp53 stability by blocking Mdm2-dependent ubiquitination and transcription of hp53 target genes. Because of the relevance of hp53 in checkpoint signaling, we hypothesize that hPer2 association with hp53 acts as a regulatory module that influences hp53's downstream response to genotoxic stress. Unlike the trimeric complex, whose distribution was confined to the nuclear compartment, hPer2/hp53 was identified in both cytosol and nucleus. At the transcriptional level, a reporter containing the hp21WAF1/CIP1 promoter, a target of hp53, remained inactive in cells expressing a stable form of the hPer2/hp53 complex even when treated with γ-radiation. Finally, we established that hPer2 directly acts on the hp53 node, as checkpoint components upstream of hp53 remained active in response to DNA damage. Quantitative transcriptional analyses of hp53 target genes demonstrated that unbound hp53 was absolutely required for activation of the DNA-damage response. Our results provide evidence of the mode by which the circadian tumor suppressor hPer2 modulates hp53 signaling in response to genotoxic stress.
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Affiliation(s)
- Tetsuya Gotoh
- Integrated Cellular Responses Laboratory, Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Marian Vila-Caballer
- Integrated Cellular Responses Laboratory, Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Jingjing Liu
- Integrated Cellular Responses Laboratory, Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Samuel Schiffhauer
- Integrated Cellular Responses Laboratory, Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Carla V Finkielstein
- Integrated Cellular Responses Laboratory, Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
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119
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Wardlaw SM, Phan TX, Saraf A, Chen X, Storm DR. Genetic disruption of the core circadian clock impairs hippocampus-dependent memory. Learn Mem 2014; 21:417-23. [PMID: 25034823 PMCID: PMC4105720 DOI: 10.1101/lm.035451.114] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 06/11/2014] [Indexed: 11/25/2022]
Abstract
Perturbing the circadian system by electrolytically lesioning the suprachiasmatic nucleus (SCN) or varying the environmental light:dark schedule impairs memory, suggesting that memory depends on the circadian system. We used a genetic approach to evaluate the role of the molecular clock in memory. Bmal1-/- mice, which are arrhythmic under constant conditions, were examined for hippocampus-dependent memory, LTP at the Schaffer-collateral synapse, and signal transduction activity in the hippocampus. Bmal1-/- mice exhibit impaired contextual fear and spatial memory. Furthermore, LTP in hippocampal slices from Bmal1-/- mice is also significantly decreased relative to that from wild-type mice. Activation of Erk1,2 MAP kinase (MAPK) during training for contextual fear memory and diurnal oscillation of MAPK activity and cAMP in the hippocampus is also lost in Bmal1-/- mice, suggesting that the memory defects are due to reduction of the memory consolidation pathway in the hippocampus. We conclude that critical signaling events in the hippocampus required for memory depend on BMAL1.
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Affiliation(s)
- Sarah M Wardlaw
- Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington 98195-7750, USA
| | - Trongha X Phan
- Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington 98195-7750, USA
| | - Amit Saraf
- Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington 98195-7750, USA
| | - Xuanmao Chen
- Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington 98195-7750, USA
| | - Daniel R Storm
- Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington 98195-7750, USA
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120
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Gerstner JR, Smith GG, Lenz O, Perron IJ, Buono RJ, Ferraro TN. BMAL1 controls the diurnal rhythm and set point for electrical seizure threshold in mice. Front Syst Neurosci 2014; 8:121. [PMID: 25018707 PMCID: PMC4071977 DOI: 10.3389/fnsys.2014.00121] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 06/09/2014] [Indexed: 11/21/2022] Open
Abstract
The epilepsies are a heterogeneous group of neurological diseases defined by the occurrence of unprovoked seizures which, in many cases, are correlated with diurnal rhythms. In order to gain insight into the biological mechanisms controlling this phenomenon, we characterized time-of-day effects on electrical seizure threshold in mice. Male C57BL/6J wild-type mice were maintained on a 14/10 h light/dark cycle, from birth until 6 weeks of age for seizure testing. Seizure thresholds were measured using a step-wise paradigm involving a single daily electrical stimulus. Results showed that the current required to elicit both generalized and maximal seizures was significantly higher in mice tested during the dark phase of the diurnal cycle compared to mice tested during the light phase. This rhythm was absent in BMAL1 knockout (KO) mice. BMAL1 KO also exhibited significantly reduced seizure thresholds at all times tested, compared to C57BL/6J mice. Results document a significant influence of time-of-day on electrical seizure threshold in mice and suggest that this effect is under the control of genes that are known to regulate circadian behaviors. Furthermore, low seizure thresholds in BMAL1 KO mice suggest that BMAL1 itself is directly involved in controlling neuronal excitability.
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Affiliation(s)
- Jason R Gerstner
- Department of Neuroscience, University of Pennsylvania Philadelphia, PA, USA ; Center for Sleep and Circadian Neurobiology, University of Pennsylvania Philadelphia, PA, USA
| | - George G Smith
- Department of Psychiatry, University of Pennsylvania Philadelphia, PA, USA ; Research Service, Department of Veterans Affairs Medical Center Coatesville, PA, USA
| | - Olivia Lenz
- Center for Sleep and Circadian Neurobiology, University of Pennsylvania Philadelphia, PA, USA
| | - Isaac J Perron
- Department of Neuroscience, University of Pennsylvania Philadelphia, PA, USA ; Center for Sleep and Circadian Neurobiology, University of Pennsylvania Philadelphia, PA, USA
| | - Russell J Buono
- Department of Biomedical Sciences, Cooper Medical School of Rowan University Camden, NJ, USA
| | - Thomas N Ferraro
- Department of Psychiatry, University of Pennsylvania Philadelphia, PA, USA ; Research Service, Department of Veterans Affairs Medical Center Coatesville, PA, USA ; Department of Biomedical Sciences, Cooper Medical School of Rowan University Camden, NJ, USA
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121
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Zhou L, Bryant CD, Loudon A, Palmer AA, Vitaterna MH, Turek FW. The circadian clock gene Csnk1e regulates rapid eye movement sleep amount, and nonrapid eye movement sleep architecture in mice. Sleep 2014; 37:785-93, 793A-793C. [PMID: 24744456 DOI: 10.5665/sleep.3590] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Efforts to identify the genetic basis of mammalian sleep have included quantitative trait locus (QTL) mapping and gene targeting of known core circadian clock genes. We combined three different genetic approaches to identify and test a positional candidate sleep gene - the circadian gene casein kinase 1 epsilon (Csnk1e), which is located in a QTL we identified for rapid eye movement (REM) sleep on chromosome 15. MEASUREMENTS AND RESULTS Using electroencephalographic (EEG) and electromyographic (EMG) recordings, baseline sleep was examined in a 12-h light:12-h dark (LD 12:12) cycle in mice of seven genotypes, including Csnk1e(tau/tau) and Csnk1e(-/-) mutant mice, Csnk1e (B6.D2) and Csnk1e (D2.B6) congenic mice, and their respective wild-type littermate control mice. Additionally, Csnk1e(tau/tau) and wild-type mice were examined in constant darkness (DD). Csnk1e(tau/tau) mutant mice and both Csnk1e (B6.D2) and Csnk1e (D2.B6) congenic mice showed significantly higher proportion of sleep time spent in REM sleep during the dark period than wild-type controls - the original phenotype for which the QTL on chromosome 15 was identified. This phenotype persisted in Csnk1e(tau/tau) mice while under free-running DD conditions. Other sleep phenotypes observed in Csnk1e(tau/tau) mice and congenics included a decreased number of bouts of nonrapid eye movement (NREM) sleep and an increased average NREM sleep bout duration. CONCLUSIONS These results demonstrate a role for Csnk1e in regulating not only the timing of sleep, but also the REM sleep amount and NREM sleep architecture, and support Csnk1e as a causal gene in the sleep QTL on chromosome 15.
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Affiliation(s)
- Lili Zhou
- Center for Sleep and Circadian Biology, Northwestern University, Evanston, IL ; Department of Neurobiology, Northwestern University, Evanston, IL
| | - Camron D Bryant
- Departments of Pharmacology and Experimental Therapeutics and Psychiatry, Boston University School of Medicine, Boston, MA
| | - Andrew Loudon
- Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Abraham A Palmer
- Department of Human Genetics, University of Chicago, Chicago, IL ; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL
| | - Martha Hotz Vitaterna
- Center for Sleep and Circadian Biology, Northwestern University, Evanston, IL ; Department of Neurobiology, Northwestern University, Evanston, IL
| | - Fred W Turek
- Center for Sleep and Circadian Biology, Northwestern University, Evanston, IL ; Department of Neurobiology, Northwestern University, Evanston, IL
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122
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Anafi RC, Lee Y, Sato TK, Venkataraman A, Ramanathan C, Kavakli IH, Hughes ME, Baggs JE, Growe J, Liu AC, Kim J, Hogenesch JB. Machine learning helps identify CHRONO as a circadian clock component. PLoS Biol 2014; 12:e1001840. [PMID: 24737000 PMCID: PMC3988006 DOI: 10.1371/journal.pbio.1001840] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 03/07/2014] [Indexed: 12/03/2022] Open
Abstract
Over the last decades, researchers have characterized a set of "clock genes" that drive daily rhythms in physiology and behavior. This arduous work has yielded results with far-reaching consequences in metabolic, psychiatric, and neoplastic disorders. Recent attempts to expand our understanding of circadian regulation have moved beyond the mutagenesis screens that identified the first clock components, employing higher throughput genomic and proteomic techniques. In order to further accelerate clock gene discovery, we utilized a computer-assisted approach to identify and prioritize candidate clock components. We used a simple form of probabilistic machine learning to integrate biologically relevant, genome-scale data and ranked genes on their similarity to known clock components. We then used a secondary experimental screen to characterize the top candidates. We found that several physically interact with known clock components in a mammalian two-hybrid screen and modulate in vitro cellular rhythms in an immortalized mouse fibroblast line (NIH 3T3). One candidate, Gene Model 129, interacts with BMAL1 and functionally represses the key driver of molecular rhythms, the BMAL1/CLOCK transcriptional complex. Given these results, we have renamed the gene CHRONO (computationally highlighted repressor of the network oscillator). Bi-molecular fluorescence complementation and co-immunoprecipitation demonstrate that CHRONO represses by abrogating the binding of BMAL1 to its transcriptional co-activator CBP. Most importantly, CHRONO knockout mice display a prolonged free-running circadian period similar to, or more drastic than, six other clock components. We conclude that CHRONO is a functional clock component providing a new layer of control on circadian molecular dynamics.
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Affiliation(s)
- Ron C. Anafi
- Division of Sleep Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- Center for Sleep and Circadian Neurobiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Yool Lee
- Department of Pharmacology and the Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Trey K. Sato
- Department of Pharmacology and the Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Anand Venkataraman
- Department of Pharmacology and the Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Chidambaram Ramanathan
- Department of Biological Sciences, University of Memphis, Memphis, Tennessee, United States of America
| | - Ibrahim H. Kavakli
- Department of Chemical and Biological Engineering, Koc University, Istanbul, Turkey
| | - Michael E. Hughes
- Department of Biology, University of Missouri–St. Louis, St. Louis, Missouri, United States of America
| | - Julie E. Baggs
- Department of Pharmacology, Morehouse School of Medicine, Atlanta, Georgia, United States of America
| | - Jacqueline Growe
- Division of Sleep Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- Center for Sleep and Circadian Neurobiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Andrew C. Liu
- Department of Biological Sciences, University of Memphis, Memphis, Tennessee, United States of America
| | - Junhyong Kim
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - John B. Hogenesch
- Center for Sleep and Circadian Neurobiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pharmacology and the Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
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123
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Rachalski A, Freyburger M, Mongrain V. Contribution of transcriptional and translational mechanisms to the recovery aspect of sleep regulation. Ann Med 2014; 46:62-72. [PMID: 24428734 DOI: 10.3109/07853890.2013.866439] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sleep parallels brain functioning and mental health. Neuronal activity during wakefulness leads to a subsequent increase in sleep intensity as measured using electroencephalographic slow-wave activity (SWA; index of neuronal synchrony in the low-frequency range). Wakefulness, and particularly prolonged wakefulness, also drives important changes in brain gene expression and changes in protein regulation. The role of these two cellular mechanisms in sleep-wake regulation has typically been studied independently, and their exact contribution to SWA remains poorly defined. In this review, we highlight that many transcriptional pathways driven by sleep deprivation are associated to protein regulation. We first describe the relationship between cytokines, clock genes, and markers of sleep need with an emphasis on transcriptional processes. Observations regarding the role of protein metabolism in sleep-wake regulation are then depicted while presenting interconnections between transcriptional and translational responses driven by sleep loss. Lastly, a manner by which this integrated response can feed back on neuronal network activity to determine sleep intensity is proposed. Overall, the literature supports that a complex cross-talk between transcriptional and translational regulation during prolonged wakefulness drives the changes in sleep intensity as a function of the sleep/wake history.
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Affiliation(s)
- Adeline Rachalski
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal , Montréal, QC , Canada
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124
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Tinarelli F, Garcia-Garcia C, Nicassio F, Tucci V. Parent-of-origin genetic background affects the transcriptional levels of circadian and neuronal plasticity genes following sleep loss. Philos Trans R Soc Lond B Biol Sci 2014; 369:20120471. [PMID: 24446504 DOI: 10.1098/rstb.2012.0471] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sleep homoeostasis refers to a process in which the propensity to sleep increases as wakefulness progresses and decreases as sleep progresses. Sleep is tightly organized around the circadian clock and is regulated by genetic and epigenetic mechanisms. The homoeostatic response of sleep, which is classically triggered by sleep deprivation, is generally measured as a rebound effect of electrophysiological measures, for example delta sleep. However, more recently, gene expression changes following sleep loss have been investigated as biomarkers of sleep homoeostasis. The genetic background of an individual may affect this sleep-dependent gene expression phenotype. In this study, we investigated whether parental genetic background differentially modulates the expression of genes following sleep loss. We tested the progeny of reciprocal crosses of AKR/J and DBA/2J mouse strains and we show a parent-of-origin effect on the expression of circadian, sleep and neuronal plasticity genes following sleep deprivation. Thus, we further explored, by in silico, specific functions or upstream mechanisms of regulation and we observed that several upstream mechanisms involving signalling pathways (i.e. DICER1, PKA), growth factors (CSF3 and BDNF) and transcriptional regulators (EGR2 and ELK4) may be differentially modulated by parental effects. This is the first report showing that a behavioural manipulation (e.g. sleep deprivation) in adult animals triggers specific gene expression responses according to parent-of-origin genomic mechanisms. Our study suggests that the same mechanism may be extended to other behavioural domains and that the investigation of gene expression following experimental manipulations should take seriously into account parent-of-origin effects.
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Affiliation(s)
- Federico Tinarelli
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, , via Morego, 30, 16163 Genova, Italy
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125
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Altered dynamics in the circadian oscillation of clock genes in dermal fibroblasts of patients suffering from idiopathic hypersomnia. PLoS One 2014; 9:e85255. [PMID: 24454829 PMCID: PMC3891749 DOI: 10.1371/journal.pone.0085255] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 11/25/2013] [Indexed: 12/27/2022] Open
Abstract
From single cell organisms to the most complex life forms, the 24-hour circadian rhythm is important for numerous aspects of physiology and behavior such as daily periodic fluctuations in body temperature and sleep-wake cycles. Influenced by environmental cues - mainly by light input -, the central pacemaker in the thalamic suprachiasmatic nuclei (SCN) controls and regulates the internal clock mechanisms which are present in peripheral tissues. In order to correlate modifications in the molecular mechanisms of circadian rhythm with the pathophysiology of idiopathic hypersomnia, this study aimed to investigate the dynamics of the expression of circadian clock genes in dermal fibroblasts of idiopathic hypersomniacs (IH) in comparison to those of healthy controls (HC). Ten clinically and polysomnographically proven IH patients were recruited from the department of sleep medicine of the University Hospital of Muenster. Clinical diagnosis was done by two consecutive polysomnographies (PSG) and Multiple Sleep Latency Test (MSLT). Fourteen clinical healthy volunteers served as control group. Dermal fibroblasts were obtained via punch biopsy and grown in cell culture. The expression of circadian clock genes was investigated by semiquantitative Reverse Transcriptase-PCR qRT-PCR analysis, confirming periodical oscillation of expression of the core circadian clock genes BMAL1, PER1/2 and CRY1/2. The amplitude of the rhythmically expressed BMAL1, PER1 and PER2 was significantly dampened in dermal fibroblasts of IH compared to HC over two circadian periods whereas the overall expression of only the key transcriptional factor BMAL1 was significantly reduced in IH. Our study suggests for the first time an aberrant dynamics in the circadian clock in IH. These findings may serve to better understand some clinical features of the pathophysiology in sleep - wake rhythms in IH.
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126
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Bailey M, Silver R. Sex differences in circadian timing systems: implications for disease. Front Neuroendocrinol 2014; 35:111-39. [PMID: 24287074 PMCID: PMC4041593 DOI: 10.1016/j.yfrne.2013.11.003] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 11/13/2013] [Accepted: 11/17/2013] [Indexed: 12/22/2022]
Abstract
Virtually every eukaryotic cell has an endogenous circadian clock and a biological sex. These cell-based clocks have been conceptualized as oscillators whose phase can be reset by internal signals such as hormones, and external cues such as light. The present review highlights the inter-relationship between circadian clocks and sex differences. In mammals, the suprachiasmatic nucleus (SCN) serves as a master clock synchronizing the phase of clocks throughout the body. Gonadal steroid receptors are expressed in almost every site that receives direct SCN input. Here we review sex differences in the circadian timing system in the hypothalamic-pituitary-gonadal axis (HPG), the hypothalamic-adrenal-pituitary (HPA) axis, and sleep-arousal systems. We also point to ways in which disruption of circadian rhythms within these systems differs in the sexes and is associated with dysfunction and disease. Understanding sex differentiated circadian timing systems can lead to improved treatment strategies for these conditions.
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Affiliation(s)
- Matthew Bailey
- Department of Psychology, Columbia University, United States.
| | - Rae Silver
- Department of Psychology, Columbia University, United States; Department of Psychology, Barnard College, United States; Department of Pathology and Cell Biology, Columbia University Medical Center, United States.
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127
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Musiek ES, Lim MM, Yang G, Bauer AQ, Qi L, Lee Y, Roh JH, Ortiz-Gonzalez X, Dearborn JT, Culver JP, Herzog ED, Hogenesch JB, Wozniak DF, Dikranian K, Giasson BI, Weaver DR, Holtzman DM, Fitzgerald GA. Circadian clock proteins regulate neuronal redox homeostasis and neurodegeneration. J Clin Invest 2013; 123:5389-400. [PMID: 24270424 PMCID: PMC3859381 DOI: 10.1172/jci70317] [Citation(s) in RCA: 359] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 08/22/2013] [Indexed: 02/05/2023] Open
Abstract
Brain aging is associated with diminished circadian clock output and decreased expression of the core clock proteins, which regulate many aspects of cellular biochemistry and metabolism. The genes encoding clock proteins are expressed throughout the brain, though it is unknown whether these proteins modulate brain homeostasis. We observed that deletion of circadian clock transcriptional activators aryl hydrocarbon receptor nuclear translocator-like (Bmal1) alone, or circadian locomotor output cycles kaput (Clock) in combination with neuronal PAS domain protein 2 (Npas2), induced severe age-dependent astrogliosis in the cortex and hippocampus. Mice lacking the clock gene repressors period circadian clock 1 (Per1) and period circadian clock 2 (Per2) had no observed astrogliosis. Bmal1 deletion caused the degeneration of synaptic terminals and impaired cortical functional connectivity, as well as neuronal oxidative damage and impaired expression of several redox defense genes. Targeted deletion of Bmal1 in neurons and glia caused similar neuropathology, despite the retention of intact circadian behavioral and sleep-wake rhythms. Reduction of Bmal1 expression promoted neuronal death in primary cultures and in mice treated with a chemical inducer of oxidative injury and striatal neurodegeneration. Our findings indicate that BMAL1 in a complex with CLOCK or NPAS2 regulates cerebral redox homeostasis and connects impaired clock gene function to neurodegeneration.
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128
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Tong X, Yin L. Circadian rhythms in liver physiology and liver diseases. Compr Physiol 2013; 3:917-40. [PMID: 23720334 DOI: 10.1002/cphy.c120017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In mammals, circadian rhythms function to coordinate a diverse panel of physiological processes with environmental conditions such as food and light. As the driving force for circadian rhythmicity, the molecular clock is a self-sustained transcription-translational feedback loop system consisting of transcription factors, epigenetic modulators, kinases/phosphatases, and ubiquitin E3 ligases. The molecular clock exists not only in the suprachiasmatic nuclei of the hypothalamus but also in the peripheral tissues to regulate cellular and physiological function in a tissue-specific manner. The circadian clock system in the liver plays important roles in regulating metabolism and energy homeostasis. Clock gene mutant animals display impaired glucose and lipid metabolism and are susceptible to diet-induced obesity and metabolic dysfunction, providing strong evidence for the connection between the circadian clock and metabolic homeostasis. Circadian-controlled hepatic metabolism is partially achieved by controlling the expression and/or activity of key metabolic enzymes, transcription factors, signaling molecules, and transporters. Reciprocally, intracellular metabolites modulate the molecular clock activity in response to the energy status. Although still at the early stage, circadian clock dysfunction has been implicated in common chronic liver diseases. Circadian dysregulation of lipid metabolism, detoxification, reactive oxygen species (ROS) production, and cell-cycle control might contribute to the onset and progression of liver steatosis, fibrosis, and even carcinogenesis. In summary, these findings call for a comprehensive study of the function and mechanisms of hepatic circadian clock to gain better understanding of liver physiology and diseases.
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Affiliation(s)
- Xin Tong
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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129
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Franken P. A role for clock genes in sleep homeostasis. Curr Opin Neurobiol 2013; 23:864-72. [DOI: 10.1016/j.conb.2013.05.002] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/01/2013] [Accepted: 05/11/2013] [Indexed: 11/27/2022]
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130
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Affiliation(s)
- Philip R. Gehrman
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, 3535 Market Street, Suite 670, Philadelphia PA 19104, 215-746-3578
| | - Cory Pfeiffenberger
- Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of Pennsylvania, Translational Research Laboratories, Suite 2100, 125 South 31st Street, Philadelphia, PA 19104-3403, (215) 746-4801
| | - Enda Byrne
- Queensland Brain Institute, Upland Road, University of Queensland, St.Lucia, QLD 4072, +61 7 3346 6300
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131
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Byrne EM, Gehrman PR, Medland SE, Nyholt DR, Heath AC, Madden PAF, Hickie IB, Van Duijn CM, Henders AK, Montgomery GW, Martin NG, Wray NR. A genome-wide association study of sleep habits and insomnia. Am J Med Genet B Neuropsychiatr Genet 2013; 162B:439-51. [PMID: 23728906 PMCID: PMC4083458 DOI: 10.1002/ajmg.b.32168] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 04/11/2013] [Indexed: 01/15/2023]
Abstract
Several aspects of sleep behavior such as timing, duration and quality have been demonstrated to be heritable. To identify common variants that influence sleep traits in the population, we conducted a genome-wide association study of six sleep phenotypes assessed by questionnaire in a sample of 2,323 individuals from the Australian Twin Registry. Genotyping was performed on the Illumina 317, 370, and 610K arrays and the SNPs in common between platforms were used to impute non-genotyped SNPs. We tested for association with more than 2,000,000 common polymorphisms across the genome. While no SNPs reached the genome-wide significance threshold, we identified a number of associations in plausible candidate genes. Most notably, a group of SNPs in the third intron of the CACNA1C gene ranked as most significant in the analysis of sleep latency (P = 1.3 × 10⁻⁶). We attempted to replicate this association in an independent sample from the Chronogen Consortium (n = 2,034), but found no evidence of association (P = 0.73). We have identified several other suggestive associations that await replication in an independent sample. We did not replicate the results from previous genome-wide analyses of self-reported sleep phenotypes after correction for multiple testing.
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Affiliation(s)
- Enda M Byrne
- Queensland Institute of Medical Research, Brisbane, Queensland, Australia.
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132
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Bunney BG, Bunney WE. Mechanisms of rapid antidepressant effects of sleep deprivation therapy: clock genes and circadian rhythms. Biol Psychiatry 2013; 73:1164-71. [PMID: 22906517 DOI: 10.1016/j.biopsych.2012.07.020] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 07/18/2012] [Accepted: 07/18/2012] [Indexed: 11/16/2022]
Abstract
A significant subset of both major depressive disorder and bipolar disorder patients rapidly (within 24 hours) and robustly improves with the chronotherapeutic intervention of sleep deprivation therapy (SDT). Major mood disorder patients are reported to have abnormal circadian rhythms including temperature, hormonal secretion, mood, and particularly sleep. These rhythms are modulated by the clock gene machinery and its products. It is hypothesized that SDT resets abnormal clock gene machinery, that relapse of depressive symptoms during recovery night sleep reactivates abnormal clock gene machinery, and that supplemental chronotherapies and medications can block relapse and help stabilize circadian-related improvement. The central circadian clock genes, BMAL1/CLOCK (NPAS2), bind to Enhancer Boxes to initiate the transcription of circadian genes, including the period genes (per1, per2, per3). It is suggested that a defect in BMAL1/CLOCK (NPAS2) or in the Enhancer Box binding contributes to altered circadian function associated, in part, with the period genes. The fact that chronotherapies, including SDT and sleep phase advance, are dramatically effective suggests that altered clock gene machinery may represent a core pathophysiological defect in a subset of mood disorder patients.
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Affiliation(s)
- Blynn G Bunney
- Department of Psychiatry, School of Medicine, University of California, Irvine, California, USA
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133
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Chen H, Zhao L, Kumazawa M, Yamauchi N, Shigeyoshi Y, Hashimoto S, Hattori MA. Downregulation of core clock gene Bmal1 attenuates expression of progesterone and prostaglandin biosynthesis-related genes in rat luteinizing granulosa cells. Am J Physiol Cell Physiol 2013; 304:C1131-40. [DOI: 10.1152/ajpcell.00008.2013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Ovarian circadian oscillators have been implicated in the reproductive processes of mammals. However, there are few reports regarding the detection of ovarian clock-controlled genes (CCGs). The present study was designed to unravel the mechanisms through which CCG ovarian circadian oscillators regulate fertility, primarily using quantitative RT-PCR and RNA interference against Bmal1 in rat granulosa cells. Mature granulosa cells were prepared from mouse Per2-destabilized luciferase ( dLuc) reporter gene transgenic rats. A real-time monitoring system of Per2 promoter activity was employed to detect Per2-dLuc oscillations. The cells exposed to luteinizing hormone (LH) displayed clear Per2-dLuc oscillations and a rhythmic expression of clock genes ( Bmal1, Per1, Per2, Rev-erbα, and Dbp). Meanwhile, the examined ovarian genes ( Star, Cyp19a1, Cyp11a1, Ptgs2, Lhcgr, and p53) showed rhythmic transcript profiles except for Hsd3b2, indicating that these rhythmic expression genes may be CCGs. Notably, Bmal1 small interfering (si)RNA treatment significantly decreased both the amplitude of Per2-dLuc oscillations and Bmal1 mRNA levels compared with nonsilencing RNA treatment in luteinizing granulosa cells. Depletion of Bmal1 by siRNA decreased the transcript levels of clock genes ( Per1, Per2, Rev-erbα, and Dbp) and examined ovarian genes ( Star, Cyp19a1, Cyp11a1, Ptgs2, Hsd3b2, and Lhcgr). Accordingly, knockdown of Bmal1 also inhibited the synthesis of progesterone and prostaglandin E2, which are associated with crucial reproductive processes. Collectively, these data suggest that ovarian circadian oscillators regulate the synthesis of steroid hormones and prostaglandins through ovarian-specific CCGs in response to LH stimuli. The present study provides new insights into the physiologic significance of Bmal1 related to fertility in ovarian circadian oscillators.
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Affiliation(s)
- Huatao Chen
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Lijia Zhao
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Makoto Kumazawa
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Nobuhiko Yamauchi
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Yasufumi Shigeyoshi
- Department of Anatomy and Neurobiology, Kinki University School of Medicine, Osaka, Japan; and
| | | | - Masa-aki Hattori
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
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134
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Sunagawa GA, Séi H, Shimba S, Urade Y, Ueda HR. FASTER: an unsupervised fully automated sleep staging method for mice. Genes Cells 2013; 18:502-18. [PMID: 23621645 PMCID: PMC3712478 DOI: 10.1111/gtc.12053] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 03/03/2013] [Indexed: 11/30/2022]
Abstract
Identifying the stages of sleep, or sleep staging, is an unavoidable step in sleep research and typically requires visual inspection of electroencephalography (EEG) and electromyography (EMG) data. Currently, scoring is slow, biased and prone to error by humans and thus is the most important bottleneck for large-scale sleep research in animals. We have developed an unsupervised, fully automated sleep staging method for mice that allows less subjective and high-throughput evaluation of sleep. Fully Automated Sleep sTaging method via EEG/EMG Recordings (FASTER) is based on nonparametric density estimation clustering of comprehensive EEG/EMG power spectra. FASTER can accurately identify sleep patterns in mice that have been perturbed by drugs or by genetic modification of a clock gene. The overall accuracy is over 90% in every group. 24-h data are staged by a laptop computer in 10 min, which is faster than an experienced human rater. Dramatically improving the sleep staging process in both quality and throughput FASTER will open the door to quantitative and comprehensive animal sleep research.
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Affiliation(s)
- Genshiro A Sunagawa
- Laboratory for Systems Biology, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
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135
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Abstract
Over more than a century of research has established the fact that sleep benefits the retention of memory. In this review we aim to comprehensively cover the field of "sleep and memory" research by providing a historical perspective on concepts and a discussion of more recent key findings. Whereas initial theories posed a passive role for sleep enhancing memories by protecting them from interfering stimuli, current theories highlight an active role for sleep in which memories undergo a process of system consolidation during sleep. Whereas older research concentrated on the role of rapid-eye-movement (REM) sleep, recent work has revealed the importance of slow-wave sleep (SWS) for memory consolidation and also enlightened some of the underlying electrophysiological, neurochemical, and genetic mechanisms, as well as developmental aspects in these processes. Specifically, newer findings characterize sleep as a brain state optimizing memory consolidation, in opposition to the waking brain being optimized for encoding of memories. Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during SWS and transform respective representations for integration into long-term memory. Ensuing REM sleep may stabilize transformed memories. While elaborated with respect to hippocampus-dependent memories, the concept of an active redistribution of memory representations from networks serving as temporary store into long-term stores might hold also for non-hippocampus-dependent memory, and even for nonneuronal, i.e., immunological memories, giving rise to the idea that the offline consolidation of memory during sleep represents a principle of long-term memory formation established in quite different physiological systems.
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Affiliation(s)
- Björn Rasch
- Division of Biopsychology, Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland.
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136
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Curie T, Mongrain V, Dorsaz S, Mang GM, Emmenegger Y, Franken P. Homeostatic and circadian contribution to EEG and molecular state variables of sleep regulation. Sleep 2013; 36:311-23. [PMID: 23450268 DOI: 10.5665/sleep.2440] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
STUDY OBJECTIVES Besides their well-established role in circadian rhythms, our findings that the forebrain expression of the clock-genes Per2 and Dbp increases and decreases, respectively, in relation to time spent awake suggest they also play a role in the homeostatic aspect of sleep regulation. Here, we determined whether time of day modulates the effects of elevated sleep pressure on clock-gene expression. Time of day effects were assessed also for recognized electrophysiological (EEG delta power) and molecular (Homer1a) markers of sleep homeostasis. DESIGN EEG and qPCR data were obtained for baseline and recovery from 6-h sleep deprivation starting at ZT0, -6, -12, or -18. SETTING Mouse sleep laboratory. PARTICIPANTS Male mice. INTERVENTIONS Sleep deprivation. RESULTS The sleep-deprivation induced changes in Per2 and Dbp expression importantly varied with time of day, such that Per2 could even decrease during sleep deprivations occurring at the decreasing phase in baseline. Dbp showed similar, albeit opposite dynamics. These unexpected results could be reliably predicted assuming that these transcripts behave according to a driven damped harmonic oscillator. As expected, the sleep-wake distribution accounted for a large degree of the changes in EEG delta power and Homer1a. Nevertheless, the sleep deprivation-induced increase in delta power varied also with time of day with higher than expected levels when recovery sleep started at dark onset. CONCLUSIONS Per2 and delta power are widely used as exclusive state variables of the circadian and homeostatic process, respectively. Our findings demonstrate a considerable cross-talk between these two processes. As Per2 in the brain responds to both sleep loss and time of day, this molecule is well positioned to keep track of and to anticipate homeostatic sleep need. CITATION Curie T; Mongrain V; Dorsaz S; Mang GM; Emmenegger Y; Franken P. Homeostatic and circadian contribution to EEG and molecular state variables of sleep regulation. SLEEP 2013;36(3):311-323.
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Affiliation(s)
- Thomas Curie
- Center for Integrative Genomics, University of Lausanne, Switzerland
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137
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Babiloni C, Infarinato F, Aujard F, Bastlund JF, Bentivoglio M, Bertini G, Del Percio C, Fabene PF, Forloni G, Herrero Ezquerro MT, Noè FM, Pifferi F, Ros-Bernal F, Christensen DZ, Dix S, Richardson JC, Lamberty Y, Drinkenburg W, Rossini PM. Effects of pharmacological agents, sleep deprivation, hypoxia and transcranial magnetic stimulation on electroencephalographic rhythms in rodents: Towards translational challenge models for drug discovery in Alzheimer’s disease. Clin Neurophysiol 2013; 124:437-51. [DOI: 10.1016/j.clinph.2012.07.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 07/05/2012] [Accepted: 07/21/2012] [Indexed: 10/27/2022]
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138
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Partonen T. Sleep needs a MOP, or two MOPs! Sleep 2013; 36:309-10. [PMID: 23450902 PMCID: PMC3571745 DOI: 10.5665/sleep.2438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- Timo Partonen
- Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki, Finland
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139
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Abstract
The sleep/wake cycle is arguably the most familiar output of the circadian system, however, sleep is a complex biological process that arises from multiple brain regions and neurotransmitters, which is regulated by numerous physiological and environmental factors. These include a circadian drive for wakefulness as well as an increase in the requirement for sleep with prolonged waking (the sleep homeostat). In this chapter, we describe the regulation of sleep, with a particular emphasis on the contribution of the circadian system. Since their identification, the role of clock genes in the regulation of sleep has attracted considerable interest, and here, we provide an overview of the interplay between specific elements of the molecular clock with the sleep regulatory system. Finally, we summarise the role of the light environment, melatonin and social cues in the modulation of sleep, with a focus on the role of melanopsin ganglion cells.
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Affiliation(s)
- Simon P Fisher
- Biosciences Division, SRI International, Centre for Neuroscience, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA
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140
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Gast H, Müller A, Lopez M, Meier D, Huber R, Dechent F, Prinz M, Emmenegger Y, Franken P, Birchler T, Fontana A. CD40 activation induces NREM sleep and modulates genes associated with sleep homeostasis. Brain Behav Immun 2013; 27:133-44. [PMID: 23072727 DOI: 10.1016/j.bbi.2012.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 10/02/2012] [Accepted: 10/02/2012] [Indexed: 01/26/2023] Open
Abstract
The T-cell derived cytokine CD40 ligand is overexpressed in patients with autoimmune diseases. Through activation of its receptor, CD40 ligand leads to a tumor necrosis factor (TNF) receptor 1 (TNFR1) dependent impairment of locomotor activity in mice. Here we report that this effect is explained through a promotion of sleep, which was specific to non-rapid eye movement (NREM) sleep while REM sleep was suppressed. The increase in NREM sleep was accompanied by a decrease in EEG delta power during NREM sleep and by a decrease in the expression of transcripts in the cerebral cortex known to be associated with homeostatic sleep drive, such as Homer1a, Early growth response 2, Neuronal pentraxin 2, and Fos-like antigen 2. The effect of CD40 activation was mimicked by peripheral TNF injection and prevented by the TNF blocker etanercept. Our study indicates that sleep-wake dysregulation in autoimmune diseases may result from CD40 induced TNF:TNFR1 mediated alterations of molecular pathways, which regulate sleep-wake behavior.
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Affiliation(s)
- Heidemarie Gast
- Department of Neurology, Inselspital, University Hospital Berne, University of Bern, Bern, Switzerland
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141
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Husse J, Hintze SC, Eichele G, Lehnert H, Oster H. Circadian clock genes Per1 and Per2 regulate the response of metabolism-associated transcripts to sleep disruption. PLoS One 2012; 7:e52983. [PMID: 23285241 PMCID: PMC3532432 DOI: 10.1371/journal.pone.0052983] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/22/2012] [Indexed: 01/23/2023] Open
Abstract
Human and animal studies demonstrate that short sleep or poor sleep quality, e.g. in night shift workers, promote the development of obesity and diabetes. Effects of sleep disruption on glucose homeostasis and liver physiology are well documented. However, changes in adipokine levels after sleep disruption suggest that adipocytes might be another important peripheral target of sleep. Circadian clocks regulate metabolic homeostasis and clock disruption can result in obesity and the metabolic syndrome. The finding that sleep and clock disruption have very similar metabolic effects prompted us to ask whether the circadian clock machinery may mediate the metabolic consequences of sleep disruption. To test this we analyzed energy homeostasis and adipocyte transcriptome regulation in a mouse model of shift work, in which we prevented mice from sleeping during the first six hours of their normal inactive phase for five consecutive days (timed sleep restriction--TSR). We compared the effects of TSR between wild-type and Per1/2 double mutant mice with the prediction that the absence of a circadian clock in Per1/2 mutants would result in a blunted metabolic response to TSR. In wild-types, TSR induces significant transcriptional reprogramming of white adipose tissue, suggestive of increased lipogenesis, together with increased secretion of the adipokine leptin and increased food intake, hallmarks of obesity and associated leptin resistance. Some of these changes persist for at least one week after the end of TSR, indicating that even short episodes of sleep disruption can induce prolonged physiological impairments. In contrast, Per1/2 deficient mice show blunted effects of TSR on food intake, leptin levels and adipose transcription. We conclude that the absence of a functional clock in Per1/2 double mutants protects these mice from TSR-induced metabolic reprogramming, suggesting a role of the circadian timing system in regulating the physiological effects of sleep disruption.
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Affiliation(s)
- Jana Husse
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | | | - Gregor Eichele
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | | | - Henrik Oster
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Medical Department I, University of Lübeck, Lübeck, Germany
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142
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Kelly JM, Bianchi MT. Mammalian sleep genetics. Neurogenetics 2012; 13:287-326. [DOI: 10.1007/s10048-012-0341-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 08/10/2012] [Indexed: 10/27/2022]
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143
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Naylor E, Aillon DV, Barrett BS, Wilson GS, Johnson DA, Johnson DA, Harmon HP, Gabbert S, Petillo PA. Lactate as a biomarker for sleep. Sleep 2012; 35:1209-22. [PMID: 22942499 DOI: 10.5665/sleep.2072] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES An ideal biomarker for sleep should change rapidly with sleep onset, remain at a detectably differential level throughout the sleep period, and exhibit a rapid change with waking. Currently, no molecular marker has been identified that exhibits all three properties. This study examined three substances (lactate, glucose, and glutamate) for suitability as a sleep biomarker. DESIGN Using amperometric biosensor technology in conjunction with electroencephalograph (EEG) and electromyograph (EMG) monitoring, extracellular concentrations of lactate and glucose (Cohort 1) as well as lactate and glutamate (Cohort 2) were recorded over multiple sleep/wake cycles. PATIENTS OR PARTICIPANTS There were 12 C57Bl/6J male mice (3-5 mo old). INTERVENTIONS Sleep and waking transitions were identified using EEG recordings. Extracellular concentrations of lactate, glucose, and glutamate were evaluated before and during transition events as well as during extended sleep and during a 6-h sleep deprivation period. MEASUREMENTS AND RESULTS Rapid and sustained increases in cortical lactate concentration (approximately 15 μM/min) were immediately observed upon waking and during rapid eye movement sleep. Elevated lactate concentration was also maintained throughout a 6-h period of continuous waking. A persistent and sustained decline in lactate concentration was measured during nonrapid eye movement sleep. Glutamate exhibited similar patterns, but with a much slower rise and decline (approximately 0.03 μM/min). Glucose concentration changes did not demonstrate a clear correlation with either sleep or wake. CONCLUSIONS These findings indicate that extracellular lactate concentration is a reliable sleep/wake biomarker and can be used independently of the EEG signal.
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Affiliation(s)
- Erik Naylor
- Pinnacle Technology, Inc., Lawrence, KS 66046, USA.
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144
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Lefta M, Campbell KS, Feng HZ, Jin JP, Esser KA. Development of dilated cardiomyopathy in Bmal1-deficient mice. Am J Physiol Heart Circ Physiol 2012; 303:H475-85. [PMID: 22707558 PMCID: PMC3423146 DOI: 10.1152/ajpheart.00238.2012] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 06/09/2012] [Indexed: 12/21/2022]
Abstract
Circadian rhythms are approximate 24-h oscillations in physiology and behavior. Circadian rhythm disruption has been associated with increased incidence of hypertension, coronary artery disease, dyslipidemia, and other cardiovascular pathologies in both humans and animal models. Mice lacking the core circadian clock gene, brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like protein (Bmal1), are behaviorally arrhythmic, die prematurely, and display a wide range of organ pathologies. However, data are lacking on the role of Bmal1 on the structural and functional integrity of cardiac muscle. In the present study, we demonstrate that Bmal1(-/-) mice develop dilated cardiomyopathy with age, characterized by thinning of the myocardial walls, dilation of the left ventricle, and decreased cardiac performance. Shortly after birth the Bmal1(-/-) mice exhibit a transient increase in myocardial weight, followed by regression and later onset of dilation and failure. Ex vivo working heart preparations revealed systolic ventricular dysfunction at the onset of dilation and failure, preceded by downregulation of both myosin heavy chain isoform mRNAs. We observed structural disorganization at the level of the sarcomere with a shift in titin isoform composition toward the stiffer N2B isoform. However, passive tension generation in single cardiomyocytes was not increased. Collectively, these findings suggest that the loss of the circadian clock gene, Bmal1, gives rise to the development of an age-associated dilated cardiomyopathy, which is associated with shifts in titin isoform composition, altered myosin heavy chain gene expression, and disruption of sarcomere structure.
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MESH Headings
- ARNTL Transcription Factors/deficiency
- ARNTL Transcription Factors/genetics
- Age Factors
- Aging
- Animals
- Cardiomyopathy, Dilated/diagnostic imaging
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/metabolism
- Cardiomyopathy, Dilated/physiopathology
- Connectin
- Disease Progression
- Gene Expression Regulation
- Heart Failure/metabolism
- Heart Failure/physiopathology
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/physiopathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle Proteins/metabolism
- Myocardial Contraction
- Myocardium/metabolism
- Myocardium/pathology
- Myosin Heavy Chains/genetics
- Myosin Heavy Chains/metabolism
- Protein Kinases/metabolism
- RNA, Messenger/metabolism
- Sarcomeres/metabolism
- Sarcomeres/pathology
- Stroke Volume
- Ultrasonography
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Function, Left
- Ventricular Pressure
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Affiliation(s)
- Mellani Lefta
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky 40536, USA
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145
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Jones CR, Huang AL, Ptáček LJ, Fu YH. Genetic basis of human circadian rhythm disorders. Exp Neurol 2012; 243:28-33. [PMID: 22849821 DOI: 10.1016/j.expneurol.2012.07.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 07/06/2012] [Accepted: 07/21/2012] [Indexed: 12/19/2022]
Abstract
Circadian rhythm disorders constitute a group of phenotypes that usually present as altered sleep-wake schedules. Until a human genetics approach was applied to investigate these traits, the genetic components regulating human circadian rhythm and sleep behaviors remained mysterious. Steady advances in the last decade have dramatically improved our understanding of the genes involved in circadian rhythmicity and sleep regulation. Finding these genes presents new opportunities to use a wide range of approaches, including in vitro molecular studies and in vivo animal modeling, to elevate our understanding of how sleep and circadian rhythms are regulated and maintained. Ultimately, this knowledge will reveal how circadian and sleep disruption contribute to various ailments and shed light on how best to maintain and recover good health.
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146
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Mavanji V, Billington CJ, Kotz CM, Teske JA. Sleep and obesity: a focus on animal models. Neurosci Biobehav Rev 2012; 36:1015-29. [PMID: 22266350 DOI: 10.1016/j.neubiorev.2012.01.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 11/25/2011] [Accepted: 01/07/2012] [Indexed: 12/19/2022]
Abstract
The rapid rise in obesity prevalence in the modern world parallels a significant reduction in restorative sleep (Agras et al., 2004; Dixon et al., 2007, 2001; Gangwisch and Heymsfield, 2004; Gupta et al., 2002; Sekine et al., 2002; Vioque et al., 2000; Wolk et al., 2003). Reduced sleep time and quality increases the risk for obesity, but the underlying mechanisms remain unclear (Gangwisch et al., 2005; Hicks et al., 1986; Imaki et al., 2002; Jennings et al., 2007; Moreno et al., 2006). A majority of the theories linking human sleep disturbances and obesity rely on self-reported sleep. However, studies with objective measurements of sleep/wake parameters suggest a U-shaped relationship between sleep and obesity. Studies in animal models are needed to improve our understanding of the association between sleep disturbances and obesity. Genetic and experimenter-induced models mimicking characteristics of human obesity are now available and these animal models will be useful in understanding whether sleep disturbances determine propensity for obesity, or result from obesity. These models exhibit weight gain profiles consistently different from control animals. Thus a careful evaluation of animal models will provide insight into the relationship between sleep disturbances and obesity in humans. In this review we first briefly consider the fundamentals of sleep and key sleep disturbances, such as sleep fragmentation and excessive daytime sleepiness (EDS), observed in obese individuals. Then we consider sleep deprivation studies and the role of circadian alterations in obesity. We describe sleep/wake changes in various rodent models of obesity and obesity resistance. Finally, we discuss possible mechanisms linking sleep disturbances with obesity.
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Affiliation(s)
- Vijayakumar Mavanji
- Minnesota Obesity Prevention Training Program, School of Public Health, University of Minnesota, Minneapolis, MN, USA.
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147
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Yasenkov R, Deboer T. Circadian modulation of sleep in rodents. PROGRESS IN BRAIN RESEARCH 2012; 199:203-218. [DOI: 10.1016/b978-0-444-59427-3.00012-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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148
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Son GH, Chung S, Kim K. The adrenal peripheral clock: glucocorticoid and the circadian timing system. Front Neuroendocrinol 2011; 32:451-65. [PMID: 21802440 DOI: 10.1016/j.yfrne.2011.07.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 04/25/2011] [Accepted: 07/06/2011] [Indexed: 12/27/2022]
Abstract
The mammalian circadian timing system is organized in a hierarchy, with the master clock residing in the suprachiasmatic nucleus (SCN) of the hypothalamus and subsidiary peripheral clocks in other brain regions as well as peripheral tissues. Since the local oscillators in most cells contain a similar molecular makeup to that in the central pacemaker, determining the role of the peripheral clocks in the regulation of rhythmic physiology and behavior is an important issue. Glucocorticoids (GCs) are a class of multi-functional adrenal steroid hormones, which exhibit a robust circadian rhythm, with a peak linked with the onset of the daily activity phase. It has long been believed that the production and secretion of GC is primarily governed through the hypothalamus-pituitary-adrenal (HPA) neuroendocrine axis in mammals. Growing evidence, however, strongly supports the notion that the periodicity of GC involves the integrated activity of multiple regulatory mechanisms related to circadian timing system along with the classical HPA neuroendocrine regulation. The adrenal-intrinsic oscillator as well as the central pacemaker plays a pivotal role in its rhythmicity. GC influences numerous biological processes, such as metabolic, cardiovascular, immune and even higher brain functions, and also acts as a resetting signal for the ubiquitous peripheral clocks, suggesting its importance in harmonizing circadian physiology and behavior. In this review, we will therefore focus on the recent advances in our understanding of the circadian regulation of adrenal GC and its functional relevance.
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Affiliation(s)
- Gi Hoon Son
- Department of Biological Sciences, Seoul National University, Brain Research Center for the 21st Century Frontier Program in Neuroscience, Seoul 151-742, Republic of Korea
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149
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Abstract
Sleep remains one of the least understood phenomena in biology--even its role in synaptic plasticity remains debatable. Since sleep was recognized to be regulated genetically, intense research has launched on two fronts: the development of model organisms for deciphering the molecular mechanisms of sleep and attempts to identify genetic underpinnings of human sleep disorders. In this Review, we describe how unbiased, high-throughput screens in model organisms are uncovering sleep regulatory mechanisms and how pathways, such as the circadian clock network and specific neurotransmitter signals, have conserved effects on sleep from Drosophila to humans. At the same time, genome-wide association studies (GWAS) have uncovered ∼14 loci increasing susceptibility to sleep disorders, such as narcolepsy and restless leg syndrome. To conclude, we discuss how these different strategies will be critical to unambiguously defining the function of sleep.
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Affiliation(s)
- Amita Sehgal
- Howard Hughes Medical institute, Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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150
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Clock genes and sleep. Pflugers Arch 2011; 463:3-14. [DOI: 10.1007/s00424-011-1003-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 07/08/2011] [Accepted: 07/22/2011] [Indexed: 11/26/2022]
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