451
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Wen S, Ma D, Zhao M, Xie L, Wu Q, Gou L, Zhu C, Fan Y, Wang H, Yan J. Spatiotemporal single-cell analysis of gene expression in the mouse suprachiasmatic nucleus. Nat Neurosci 2020; 23:456-467. [DOI: 10.1038/s41593-020-0586-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 01/03/2020] [Indexed: 12/11/2022]
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452
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Interplay of chronotype and school timing predicts school performance. Nat Hum Behav 2020; 4:387-396. [PMID: 32042108 DOI: 10.1038/s41562-020-0820-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 01/05/2020] [Indexed: 12/21/2022]
Abstract
Most adolescents exhibit very late chronotypes and attend school early in the morning, a misalignment that can affect their health and psychological well-being. Here we examine how the interaction between the chronotype and school timing of an individual influences academic performance, studying a unique sample of 753 Argentinian students who were randomly assigned to start school in the morning (07:45), afternoon (12:40) or evening (17:20). Although chronotypes tend to align partially with class time, this effect is insufficient to fully account for the differences with school start time. We show that (1) for morning-attending students, early chronotypes perform better than late chronotypes in all school subjects, an effect that is largest for maths; (2) this effect vanishes for students who attend school in the afternoon; and (3) late chronotypes benefit from evening classes. Together, these results demonstrate that academic performance is improved when school times are better aligned with the biological rhythms of adolescents.
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453
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Immune cell regulation of glia during CNS injury and disease. Nat Rev Neurosci 2020; 21:139-152. [DOI: 10.1038/s41583-020-0263-9] [Citation(s) in RCA: 146] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2020] [Indexed: 12/13/2022]
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454
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Aguilar-López BA, Moreno-Altamirano MMB, Dockrell HM, Duchen MR, Sánchez-García FJ. Mitochondria: An Integrative Hub Coordinating Circadian Rhythms, Metabolism, the Microbiome, and Immunity. Front Cell Dev Biol 2020; 8:51. [PMID: 32117978 PMCID: PMC7025554 DOI: 10.3389/fcell.2020.00051] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/20/2020] [Indexed: 12/25/2022] Open
Abstract
There is currently some understanding of the mechanisms that underpin the interactions between circadian rhythmicity and immunity, metabolism and immune response, and circadian rhythmicity and metabolism. In addition, a wealth of studies have led to the conclusion that the commensal microbiota (mainly bacteria) within the intestine contributes to host homeostasis by regulating circadian rhythmicity, metabolism, and the immune system. Experimental studies on how these four biological domains interact with each other have mainly focused on any two of those domains at a time and only occasionally on three. However, a systematic analysis of how these four domains concurrently interact with each other seems to be missing. We have analyzed current evidence that signposts a role for mitochondria as a key hub that supports and integrates activity across all four domains, circadian clocks, metabolic pathways, the intestinal microbiota, and the immune system, coordinating their integration and crosstalk. This work will hopefully provide a new perspective for both hypothesis-building and more systematic experimental approaches.
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Affiliation(s)
- Bruno A Aguilar-López
- Laboratorio de Inmunorregulación, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - Hazel M Dockrell
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Francisco Javier Sánchez-García
- Laboratorio de Inmunorregulación, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
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455
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Hastings MH, Smyllie NJ, Patton AP. Molecular-genetic Manipulation of the Suprachiasmatic Nucleus Circadian Clock. J Mol Biol 2020; 432:3639-3660. [PMID: 31996314 DOI: 10.1016/j.jmb.2020.01.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 01/08/2023]
Abstract
Circadian (approximately daily) rhythms of physiology and behaviour adapt organisms to the alternating environments of day and night. The suprachiasmatic nucleus (SCN) of the hypothalamus is the principal circadian timekeeper of mammals. The mammalian cell-autonomous circadian clock is built around a self-sustaining transcriptional-translational negative feedback loop (TTFL) in which the negative regulators Per and Cry suppress their own expression, which is driven by the positive regulators Clock and Bmal1. Importantly, such TTFL-based clocks are present in all major tissues across the organism, and the SCN is their central co-ordinator. First, we analyse SCN timekeeping at the cell-autonomous and the circuit-based levels of organisation. We consider how molecular-genetic manipulations have been used to probe cell-autonomous timing in the SCN, identifying the integral components of the clock. Second, we consider new approaches that enable real-time monitoring of the activity of these clock components and clock-driven cellular outputs. Finally, we review how intersectional genetic manipulations of the cell-autonomous clockwork can be used to determine how SCN cells interact to generate an ensemble circadian signal. Critically, it is these network-level interactions that confer on the SCN its emergent properties of robustness, light-entrained phase and precision- properties that are essential for its role as the central co-ordinator. Remaining gaps in knowledge include an understanding of how the TTFL proteins behave individually and in complexes: whether particular SCN neuronal populations act as pacemakers, and if so, by which signalling mechanisms, and finally the nature of the recently discovered role of astrocytes within the SCN network.
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Affiliation(s)
- Michael H Hastings
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK.
| | - Nicola J Smyllie
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - Andrew P Patton
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
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456
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Sleep Quality of Hospitalized Patients, Contributing Factors, and Prevalence of Associated Disorders. SLEEP DISORDERS 2020; 2020:8518396. [PMID: 32308998 PMCID: PMC7157800 DOI: 10.1155/2020/8518396] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 01/04/2020] [Indexed: 11/18/2022]
Abstract
Background Data in the literature has shown poor sleep quality to be frequently observed in hospitalized patients and known to be associated with poor treatment outcome. Many factors may impact poor sleep quality, and there is currently limited available data. We aim to determine the prevalence of poor sleep quality and associated factors in patients admitted to internal medicine wards as well as the change of sleep quality over time after admission. Methods An analytic observational study was conducted at the internal medicine wards at the King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Patients were personally interviewed to evaluate the history of sleep quality at home, sleep quality after the first and the third days of admission, and potential associated factors. The Pittsburgh Sleep Quality Index and screening questionnaires for the common diseases associated with poor sleep quality were also utilized. The logistic regression analysis was used to determine the independent factors which led to poor sleep quality. Results Data were collected from 96 patients during the period of June 2015 to February 2016. The mean age of the patients was 50.8 ± 16.7 years, and 51% were male. Infectious disease was the most common principal diagnosis accounted for 29.2%. The results show high prevalence of poor sleep quality after the first night of admission compared to baseline sleep quality at home (50% vs. 18.8%; p < 0.001). After 3 days of admission, the prevalence of poor sleep quality was reduced to the level close to baseline sleep quality at home (28.1% vs. 18.8%; p = 0.13). Multivariate analysis demonstrated that light exposure and pain were the main independent factors for poor sleep quality on the first day (odds ratio 6.68; 95% CI 2.25-19.84) and on the third day (odds ratio 3.47; 95% CI 1.24-9.71), respectively. Conclusions This is the first study conducted on the sleep quality of hospitalized patients that included the follow-up period during hospital admission. Our study demonstrated high prevalence of poor sleep quality in hospitalized patients on the first day. Interestingly, the sleep quality was partly improved during hospitalization. Light exposure and pain were demonstrated to be the factors associated with poor sleep quality.
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457
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Plangsangmas T, Brown JL, Thitaram C, Silva-Fletcher A, Edwards KL, Punyapornwithaya V, Towiboon P, Somgird C. Circadian Rhythm of Salivary Immunoglobulin A and Associations with Cortisol as A Stress Biomarker in Captive Asian Elephants ( Elephas maximus). Animals (Basel) 2020; 10:ani10010157. [PMID: 31963391 PMCID: PMC7023042 DOI: 10.3390/ani10010157] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/12/2020] [Accepted: 01/13/2020] [Indexed: 01/24/2023] Open
Abstract
Salivary immunoglobulin A (sIgA) has been proposed as a potential indicator of welfare for various species, including Asian elephants, and may be related to adrenal cortisol responses. This study aimed to distinguish circadian rhythm effects on sIgA in male and female Asian elephants and compare patterns to those of salivary cortisol, information that could potentially have welfare implications. Subjects were captive elephants at an elephant camp in Chiang Mai province, Thailand (n = 5 males, 5 females). Salivette® kits were used to collect saliva from each elephant every 4 h from 06:00 to 22:00 h for 3 consecutive days (n = 15 samples/elephant). Enzyme immunoassays were used to quantify concentrations of IgA and cortisol in unextracted saliva. Circadian rhythm patterns were determined using a generalized least-squares method. Both sIgA and cortisol followed a circadian rhythm, although the patterns differed. sIgA displayed a daily quartic trend, whereas cortisol concentrations demonstrated a decreasing linear trend in concentrations throughout the day. There was no clear relationship between patterns of sIgA and salivary cortisol, implying that mechanisms of control and secretion differ. Results demonstrate for the first time that circadian rhythms affect sIgA, and concentrations follow a daily quartic pattern in Asian elephants, so standardizing time of collection is necessary.
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Affiliation(s)
- Tithipong Plangsangmas
- Master’s Degree Program in Veterinary Science, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
- Center of Elephant and Wildlife Research, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Janine L. Brown
- Center for Species Survival, Smithsonian Conservation Biology Institute, Front Royal, VA 22630, USA
| | - Chatchote Thitaram
- Center of Elephant and Wildlife Research, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
- Department of Companion Animal and Wildlife Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Mae Hia, Chiang Mai 50100, Thailand
| | - Ayona Silva-Fletcher
- Department of Clinical Sciences and Services, The Royal Veterinary College, Hawkshead Lane, Hertfordshire AL9 7TA, UK
| | - Katie L. Edwards
- Center for Species Survival, Smithsonian Conservation Biology Institute, Front Royal, VA 22630, USA
- North of England Zoological Society, Chester Zoo, Upton-by-Chester, CH2 1LH, UK
| | - Veerasak Punyapornwithaya
- Veterinary Public Health and Food Safety Centre for Asia Pacific (VPHCAP), Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Patcharapa Towiboon
- Center of Elephant and Wildlife Research, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Chaleamchat Somgird
- Center of Elephant and Wildlife Research, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
- Department of Companion Animal and Wildlife Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Mae Hia, Chiang Mai 50100, Thailand
- Correspondence: ; Tel.: +66-53948-015
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Abstract
PURPOSE OF REVIEW This review is focused on the existing evidence for circadian control of innate and adaptive immune responses to provide a framework for evaluating the contributions of diurnal rhythms to control of infections and pathogenesis of disease. RECENT FINDINGS Circadian rhythms driven by cell-autonomous biological clocks are central to innate and adaptive immune responses against microbial pathogens. Research during the past few years has uncovered circadian circuits governing leukocyte migration between tissues, the magnitude of mucosal inflammation, the types of cytokines produced, and the severity of immune diseases. Other studies revealed how disruption of the circadian clock impairs immune function or how microbial products alter clock machinery. Revelations concerning the widespread impact of the circadian clock on immunity and homeostasis highlight how the timing of inflammatory challenges can dictate pathological outcomes and how the timing of therapeutic interventions likely determines clinical efficacy. An improved understanding of circadian circuits controlling immune function will facilitate advances in circadian immunotherapy.
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Affiliation(s)
- Stephen N Waggoner
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, 45244, USA.
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, MLC 15012, Cincinnati, OH, 45244, USA.
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459
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Pilorz V, Astiz M, Heinen KO, Rawashdeh O, Oster H. The Concept of Coupling in the Mammalian Circadian Clock Network. J Mol Biol 2020; 432:3618-3638. [PMID: 31926953 DOI: 10.1016/j.jmb.2019.12.037] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/22/2019] [Accepted: 12/23/2019] [Indexed: 12/13/2022]
Abstract
The circadian clock network regulates daily rhythms in mammalian physiology and behavior to optimally adapt the organism to the 24-h day/night cycle. A central pacemaker, the hypothalamic suprachiasmatic nucleus (SCN), coordinates subordinate cellular oscillators in the brain, as well as in peripheral organs to align with each other and external time. Stability and coordination of this vast network of cellular oscillators is achieved through different levels of coupling. Although coupling at the molecular level and across the SCN is well established and believed to define its function as pacemaker structure, the notion of coupling in other tissues and across the whole system is less well understood. In this review, we describe the different levels of coupling in the mammalian circadian clock system - from molecules to the whole organism. We highlight recent advances in gaining knowledge of the complex organization and function of circadian network regulation and its significance for the generation of stable but plastic intrinsic 24-h rhythms.
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Affiliation(s)
- Violetta Pilorz
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Mariana Astiz
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Keno Ole Heinen
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Oliver Rawashdeh
- The University of Queensland, School of Biomedical Sciences, Faculty of Medicine, St Lucia Qld, 4071, Australia
| | - Henrik Oster
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany.
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460
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Mauvoisin D, Gachon F. Proteomics in Circadian Biology. J Mol Biol 2019; 432:3565-3577. [PMID: 31843517 DOI: 10.1016/j.jmb.2019.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/09/2019] [Accepted: 12/09/2019] [Indexed: 02/06/2023]
Abstract
The circadian clock is an endogenous molecular timekeeping system that allows organisms to adjust their physiology and behavior to the time of day in an anticipatory fashion. In different organisms, the circadian clock coordinates physiology and metabolism through regulation of gene expression at the transcriptional and post-transcriptional levels. Until now, circadian gene expression studies have mostly focused primarily on transcriptomics approaches. This type of analyses revealed that many protein-encoding genes show circadian expression in a tissue-specific manner. During the last three decades, a long way has been traveled since the pioneering work on dinoflagellates, and new advances in mass spectrometry offered new perspectives in the characterization of the circadian dynamics of the proteome. Altogether, these efforts highlighted that rhythmic protein oscillation is driven equally by gene transcription, post-transcriptional and post-translational regulations. The determination of the role of the circadian clock in these three levels of regulation appears to be the next major challenge in the field.
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Affiliation(s)
- Daniel Mauvoisin
- L'institut Du Thorax, INSERM, CNRS, UNIV Nantes, Nantes, France.
| | - Frédéric Gachon
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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461
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Circadian rhythms in Per1, PER2 and Ca 2+ of a solitary SCN neuron cultured on a microisland. Sci Rep 2019; 9:18271. [PMID: 31797953 PMCID: PMC6892917 DOI: 10.1038/s41598-019-54654-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/01/2019] [Indexed: 01/08/2023] Open
Abstract
Circadian rhythms in Per1, PER2 expression and intracellular Ca2+ were measured from a solitary SCN neuron or glial cell which was physically isolated from other cells. Dispersed cells were cultured on a platform of microisland (100–200 μm in diameter) in a culture dish. Significant circadian rhythms were detected in 57.1% for Per1 and 70.0% for PER2 expression. When two neurons were located on the same island, the circadian rhythms showed desynchronization, indicating a lack of oscillatory coupling. Circadian rhythms were also detected in intracellular Ca2+ of solitary SCN neurons. The ratio of circadian positive neurons was significantly larger without co-habitant of glial cells (84.4%) than with it (25.0%). A relatively large fraction of SCN neurons generates the intrinsic circadian oscillation without neural or humoral networks. In addition, glial cells seem to interrupt the expression of the circadian rhythmicity of intracellular Ca2+ under these conditions.
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462
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Sládek M, Houdek P, Sumová A. Circadian profiling reveals distinct regulation of endocannabinoid system in the rat plasma, liver and adrenal glands by light-dark and feeding cycles. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:158533. [DOI: 10.1016/j.bbalip.2019.158533] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 09/19/2019] [Accepted: 09/25/2019] [Indexed: 12/17/2022]
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463
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Northeast RC, Chrobok L, Hughes ATL, Petit C, Piggins HD. Keeping time in the lamina terminalis: Novel oscillator properties of forebrain sensory circumventricular organs. FASEB J 2019; 34:974-987. [PMID: 31914667 PMCID: PMC6972491 DOI: 10.1096/fj.201901111r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 09/19/2019] [Accepted: 10/15/2019] [Indexed: 12/11/2022]
Abstract
Drinking behavior and osmotic regulatory mechanisms exhibit clear daily variation which is necessary for achieving the homeostatic osmolality. In mammals, the master clock in the brain's suprachiasmatic nuclei has long been held as the main driver of circadian (24 h) rhythms in physiology and behavior. However, rhythmic clock gene expression in other brain sites raises the possibility of local circadian control of neural activity and function. The subfornical organ (SFO) and the organum vasculosum laminae terminalis (OVLT) are two sensory circumventricular organs (sCVOs) that play key roles in the central control of thirst and water homeostasis, but the extent to which they are subject to intrinsic circadian control remains undefined. Using a combination of ex vivo bioluminescence and in vivo gene expression, we report for the first time that the SFO contains an unexpectedly robust autonomous clock with unusual spatiotemporal characteristics in core and noncore clock gene expression. Furthermore, putative single-cell oscillators in the SFO and OVLT are strongly rhythmic and require action potential-dependent communication to maintain synchrony. Our results reveal that these thirst-controlling sCVOs possess intrinsic circadian timekeeping properties and raise the possibility that these contribute to daily regulation of drinking behavior.
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Affiliation(s)
- Rebecca C Northeast
- Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, UK
| | - Lukasz Chrobok
- Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, UK
| | - Alun T L Hughes
- Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, UK
| | - Cheryl Petit
- Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, UK
| | - Hugh D Piggins
- Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, UK
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464
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Molecular mechanisms and physiological importance of circadian rhythms. Nat Rev Mol Cell Biol 2019; 21:67-84. [PMID: 31768006 DOI: 10.1038/s41580-019-0179-2] [Citation(s) in RCA: 577] [Impact Index Per Article: 115.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2019] [Indexed: 12/12/2022]
Abstract
To accommodate daily recurring environmental changes, animals show cyclic variations in behaviour and physiology, which include prominent behavioural states such as sleep-wake cycles but also a host of less conspicuous oscillations in neurological, metabolic, endocrine, cardiovascular and immune functions. Circadian rhythmicity is created endogenously by genetically encoded molecular clocks, whose components cooperate to generate cyclic changes in their own abundance and activity, with a periodicity of about a day. Throughout the body, such molecular clocks convey temporal control to the function of organs and tissues by regulating pertinent downstream programmes. Synchrony between the different circadian oscillators and resonance with the solar day is largely enabled by a neural pacemaker, which is directly responsive to certain environmental cues and able to transmit internal time-of-day representations to the entire body. In this Review, we discuss aspects of the circadian clock in Drosophila melanogaster and mammals, including the components of these molecular oscillators, the function and mechanisms of action of central and peripheral clocks, their synchronization and their relevance to human health.
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465
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Rohr KE, Pancholi H, Haider S, Karow C, Modert D, Raddatz NJ, Evans J. Seasonal plasticity in GABA A signaling is necessary for restoring phase synchrony in the master circadian clock network. eLife 2019; 8:49578. [PMID: 31746738 PMCID: PMC6867713 DOI: 10.7554/elife.49578] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 10/15/2019] [Indexed: 12/14/2022] Open
Abstract
Annual changes in the environment threaten survival, and numerous biological processes in mammals adjust to this challenge via seasonal encoding by the suprachiasmatic nucleus (SCN). To tune behavior according to day length, SCN neurons display unified rhythms with synchronous phasing when days are short, but will divide into two sub-clusters when days are long. The transition between SCN states is critical for maintaining behavioral responses to seasonal change, but the mechanisms regulating this form of neuroplasticity remain unclear. Here we identify that a switch in chloride transport and GABAA signaling is critical for maintaining state plasticity in the SCN network. Further, we reveal that blocking excitatory GABAA signaling locks the SCN into its long day state. Collectively, these data demonstrate that plasticity in GABAA signaling dictates how clock neurons interact to maintain environmental encoding. Further, this work highlights factors that may influence susceptibility to seasonal disorders in humans. In winter, as the days become shorter, millions of people find that their mood and energy levels start to drop. They crave carbohydrates, struggle with their weight, and find it harder to get out of bed in the mornings. These individuals are suffering from the ‘winter blues’ or seasonal affective disorder (SAD), and most find that their symptoms spontaneously improve in the spring when the days become longer again. Many also benefit from bright light therapy during the winter months, but not everyone responds fully to this treatment, so additional options are needed. The winter blues occur when the brain adjusts to changes in day length with the onset of winter. The brain region responsible for making this adjustment is the suprachiasmatic nucleus (SCN). The SCN is the master clock of the brain that coordinates the body’s circadian rhythms – the daily fluctuations in things like appetite, body temperature, sleep and wakefulness. But as well as being the brain’s clock, the SCN is also the brain’s calendar. In winter, when the days are short, SCN neurons coordinate their activity and fire in synchrony. But in summer, when the days are long, SCN neurons divide into two clusters, which fire at different times. By transitioning between these two states, the SCN helps the body adjust to seasonal changes in day length. Rohr, Pancholi et al. now provide new insight into the mechanism behind this process by showing that light alters the neurochemistry of the SCN. Exposing mice to long days causes a brain chemical called GABA to switch from inhibiting neurons in the SCN to activating them. Blocking this switch from inhibition to activation locks the SCN into its 'summer state'. Rohr, Pancholi et al. propose that this failure to transition to the winter state may be an interesting way to prevent the winter blues. While much remains to be learned about this process, these findings pave the way for better understanding the neurobiology of winter depression and how best to treat it.
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Affiliation(s)
- Kayla E Rohr
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Harshida Pancholi
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Shabi Haider
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Christopher Karow
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - David Modert
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Nicholas J Raddatz
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Jennifer Evans
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
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466
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Mishra I, Knerr RM, Stewart AA, Payette WI, Richter MM, Ashley NT. Light at night disrupts diel patterns of cytokine gene expression and endocrine profiles in zebra finch (Taeniopygia guttata). Sci Rep 2019; 9:15833. [PMID: 31676761 PMCID: PMC6825233 DOI: 10.1038/s41598-019-51791-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 10/08/2019] [Indexed: 11/22/2022] Open
Abstract
Increased exposure to light pollution perturbs physiological processes through misalignment of daily rhythms at the cellular and tissue levels. Effects of artificial light-at-night (ALAN) on diel properties of immunity are currently unknown. We therefore tested the effects of ALAN on diel patterns of cytokine gene expression, as well as key hormones involved with the regulation of immunity, in zebra finches (Taeniopygia guttata). Circulating melatonin and corticosterone, and mRNA expression levels of pro- (IL-1β, IL-6) and anti-inflammatory (IL-10) cytokines were measured at six time points across 24-h day in brain (nidopallium, hippocampus, and hypothalamus) and peripheral tissues (liver, spleen, and fat) of zebra finches exposed to 12 h light:12 h darkness (LD), dim light-at-night (DLAN) or constant bright light (LLbright). Melatonin and corticosterone concentrations were significantly rhythmic under LD, but not under LLbright and DLAN. Genes coding for cytokines showed tissue-specific diurnal rhythms under LD and were lost with exposure to LLbright, except IL-6 in hypothalamus and liver. In comparison to LLbright, effects of DLAN were less adverse with persistence of some diurnal rhythms, albeit with significant waveform alterations. These results underscore the circadian regulation of biosynthesis of immune effectors and imply the susceptibility of daily immune and endocrine patterns to ALAN.
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Affiliation(s)
- Ila Mishra
- Department of Biology, Western Kentucky University, Bowling Green, KY, USA
| | - Reinhard M Knerr
- Department of Biology, Western Kentucky University, Bowling Green, KY, USA
| | | | - Wesley I Payette
- Department of Biology, Western Kentucky University, Bowling Green, KY, USA
| | - Melanie M Richter
- Department of Biology, Western Kentucky University, Bowling Green, KY, USA
| | - Noah T Ashley
- Department of Biology, Western Kentucky University, Bowling Green, KY, USA.
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467
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Cox KH, Takahashi JS. Circadian clock genes and the transcriptional architecture of the clock mechanism. J Mol Endocrinol 2019; 63:R93-R102. [PMID: 31557726 PMCID: PMC6872945 DOI: 10.1530/jme-19-0153] [Citation(s) in RCA: 228] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 09/26/2019] [Indexed: 12/12/2022]
Abstract
The mammalian circadian clock has evolved as an adaptation to the 24-h light/darkness cycle on earth. Maintaining cellular activities in synchrony with the activities of the organism (such as eating and sleeping) helps different tissue and organ systems coordinate and optimize their performance. The full extent of the mechanisms by which cells maintain the clock are still under investigation, but involve a core set of clock genes that regulate large networks of gene transcription both by direct transcriptional activation/repression as well as the recruitment of proteins that modify chromatin states more broadly.
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Affiliation(s)
- Kimberly H. Cox
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Joseph S. Takahashi
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
- To whom correspondence should be addressed:
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468
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Hilbert DA, Memmert S, Marciniak J, Jäger A. Molecular biology of periodontal ligament fibroblasts and orthodontic tooth movement : Evidence and possible role of the circadian rhythm. J Orofac Orthop 2019; 80:336-347. [PMID: 31650205 DOI: 10.1007/s00056-019-00195-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 08/03/2019] [Indexed: 12/26/2022]
Abstract
PURPOSE The circadian clock plays an important role in many physiological states and pathologies. The significance of its core genes in bone formation and tooth development has already been demonstrated. However, regulation of these genes and their influence on periodontal and bone remodeling in periodontal ligament (PDL) fibroblasts remains to be elucidated. Our hypothesis was that the circadian clock influences markers for periodontal and bone remodeling and therefore orthodontic tooth movement itself. MATERIALS AND METHODS Human PDL fibroblasts were cultured and synchronized in circadian rhythms with the help of a dexamethasone shock. Cells were harvested at 4 h intervals. Reverse transcription and quantitative RT PCR (real time polymerase chain reaction) were performed to assess the mRNA levels of the clock genes ARNTL, CLOCK1, PER1, and PER2. Subsequently, mRNA expression of important marker genes for periodontal and bone remodeling, OPG, RANKL, OCN, OPN, RUNX2, COL1A1, IL1β, KI67, and POSTN, were examined at time points of ARNTL amplitude expression. RESULTS Gene expression of core clock genes varied over 48 h in accordance with the circadian rhythm. Functional markers, except KI67, showed significant differences at time points of maximum fluctuation especially of ARNTL. CONCLUSIONS PDL fibroblasts express circadian clock genes. Our results suggest that genes associated with bone and periodontal remodeling are influenced by the circadian rhythm. Further research will have to refine the understanding of this influence for orthodontic treatment.
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Affiliation(s)
- David Andreas Hilbert
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany.
| | - Svenja Memmert
- Department of Orthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany.,Section of Experimental Dento-Maxillo-Facial Medicine, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany
| | - Jana Marciniak
- Department of Orthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany
| | - Andreas Jäger
- Department of Orthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany
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469
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Abstract
Like it or not, your two suprachiasmatic nuclei (SCN) govern your life: from when you wake up and fall asleep, to when you feel hungry or can best concentrate. Each is composed of approximately 10,000 tightly interconnected neurons, and the pair sit astride the mid-line third ventricle of the hypothalamus, immediately dorsal to the optic chiasm (Figure 1A). Together, they constitute the master circadian clock of the mammalian brain. They generate an internal representation of solar time that is conveyed to every cell in our body and in this way they co-ordinate the daily cycles of physiology and behaviour that adapt us to the twenty-four hour world. The temporary discomfort associated with jetlag is a reminder of the importance of this daily programme, but there is growing recognition that its chronic disruption carries a cost for health of far greater scale. In this primer, we shall briefly review the historical identification of the SCN as the master circadian clock, and then discuss it on three different levels: the cell-autonomous SCN, the SCN as a cellular network and, finally, the SCN as circadian orchestrator. We shall focus on the intrinsic electrical and transcriptional properties of the SCN and how these properties are thought to form an input to, and an output from, its intrinsic cellular clockwork. Second, we shall describe the anatomical arrangement of the SCN, how its sub-regions are delineated by different neuropeptides, and how SCN neurons communicate with each other via these neuropeptides and the neurotransmitter γ-aminobutyric acid (GABA). Finally, we shall discuss how the SCN functions as a circadian oscillator that dictates behaviour, and how intersectional genetic approaches are being used to try to unravel the specific contributions to pacemaking of specific SCN cell populations.
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Affiliation(s)
- Andrew P Patton
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Michael H Hastings
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
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470
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Spulber S, Conti M, Elberling F, Raciti M, Borroto-Escuela DO, Fuxe K, Ceccatelli S. Desipramine restores the alterations in circadian entrainment induced by prenatal exposure to glucocorticoids. Transl Psychiatry 2019; 9:263. [PMID: 31624238 PMCID: PMC6797805 DOI: 10.1038/s41398-019-0594-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 09/09/2019] [Accepted: 09/24/2019] [Indexed: 11/16/2022] Open
Abstract
Alterations in circadian rhythms are closely linked to depression, and we have shown earlier that progressive alterations in circadian entrainment precede the onset of depression in mice exposed in utero to excess glucocorticoids. The aim of this study was to investigate whether treatment with the noradrenaline reuptake inhibitor desipramine (DMI) could restore the alterations in circadian entrainment and prevent the onset of depression-like behavior. C57Bl/6 mice were exposed to dexamethasone (DEX-synthetic glucocorticoid analog, 0.05 mg/kg/day) between gestational day 14 and delivery. Male offspring aged 6 months (mo) were treated with DMI (10 mg/kg/day in drinking water) for at least 21 days before behavioral testing. We recorded spontaneous activity using the TraffiCage™ system and found that DEX mice re-entrained faster than controls after an abrupt advance in light-dark cycle by 6 h, while DMI treatment significantly delayed re-entrainment. Next we assessed the synchronization of peripheral oscillators with the central clock (located in the suprachiasmatic nucleus-SCN), as well as the mechanisms required for entrainment. We found that photic entrainment of the SCN was apparently preserved in DEX mice, but the expression of clock genes in the hippocampus was not synchronized with the light-dark cycle. This was associated with downregulated mRNA expression for arginine vasopressin (AVP; the main molecular output entraining peripheral clocks) in the SCN, and for glucocorticoid receptor (GR; required for the negative feedback loop regulating glucocorticoid secretion) in the hippocampus. DMI treatment restored the mRNA expression of AVP in the SCN and enhanced GR-mediated signaling by upregulating GR expression and nuclear translocation in the hippocampus. Furthermore, DMI treatment at 6 mo prevented the onset of depression-like behavior and the associated alterations in neurogenesis in 12-mo-old DEX mice. Taken together, our data indicate that DMI treatment enhances GR-mediated signaling and restores the synchronization of peripheral clocks with the SCN and support the hypothesis that altered circadian entrainment is a modifiable risk factor for depression.
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Affiliation(s)
- Stefan Spulber
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | - Mirko Conti
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | | | - Marilena Raciti
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | | | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Sandra Ceccatelli
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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471
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Brunet A, Forsberg F, Fan Q, Sæther T, Collas P. Nuclear Lamin B1 Interactions With Chromatin During the Circadian Cycle Are Uncoupled From Periodic Gene Expression. Front Genet 2019; 10:917. [PMID: 31632442 PMCID: PMC6785633 DOI: 10.3389/fgene.2019.00917] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/30/2019] [Indexed: 12/17/2022] Open
Abstract
Many mammalian genes exhibit circadian expression patterns concordant with periodic binding of transcription factors, chromatin modifications, and chromosomal interactions. Here we investigate whether chromatin periodically associates with nuclear lamins. Entrainment of the circadian clock is accompanied, in mouse liver, by a net gain of lamin B1–chromatin interactions genome-wide, after which the majority of lamina-associated domains (LADs) are conserved during the circadian cycle. By tailoring a bioinformatics pipeline designed to identify periodic gene expression patterns, we also observe hundreds of variable lamin B1–chromatin interactions among which oscillations occur at 64 LADs, affecting one or both LAD extremities or entire LADs. Only a small subset of these oscillations however exhibit highly significant 12, 18, 24, or 30 h periodicity. These periodic LADs display oscillation asynchrony between their 5′ and 3′ borders, and are uncoupled from periodic gene expression within or in the vicinity of these LADs. Periodic gene expression is also unrelated to variations in gene-to-nearest LAD distances detected during the circadian cycle. Accordingly, periodic genes, including central clock-control genes, are located megabases away from LADs throughout circadian time, suggesting stable residence in a transcriptionally permissive chromatin environment. We conclude that periodic LADs are not a dominant feature of variable lamin B1–chromatin interactions during the circadian cycle in mouse liver. Our results also suggest that periodic hepatic gene expression is not regulated by rhythmic chromatin associations with the nuclear lamina.
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Affiliation(s)
- Annaël Brunet
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Frida Forsberg
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Qiong Fan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Thomas Sæther
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
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472
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Droin C, Paquet ER, Naef F. Low-dimensional Dynamics of Two Coupled Biological Oscillators. NATURE PHYSICS 2019; 15:1086-1094. [PMID: 32528550 PMCID: PMC7289635 DOI: 10.1038/s41567-019-0598-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 06/18/2019] [Indexed: 06/11/2023]
Abstract
The circadian clock and the cell cycle are two biological oscillatory processes that coexist within individual cells. These two oscillators were found to interact, which can lead to their synchronization. Here, we develop a method to identify a low-dimensional stochastic model of the coupled system directly from time-lapse imaging in single cells. In particular, we infer the coupling and non-linear dynamics of the two oscillators from thousands of mouse and human single-cell fluorescence microscopy traces. This coupling predicts multiple phase-locked states showing different degrees of robustness against molecular fluctuations inherent to cellular-scale biological oscillators. For the 1:1 state, the predicted phase-shifts upon period perturbations were validated experimentally. Moreover, the phase-locked states are temperature-independent and evolutionarily conserved from mouse to human, hinting at a common underlying dynamical mechanism. Finally, we detect a signature of the coupled dynamics in a physiological context, explaining why tissues with different proliferation states exhibited shifted circadian clock phases.
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473
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474
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Mendoza J. Circadian insights into the biology of depression: Symptoms, treatments and animal models. Behav Brain Res 2019; 376:112186. [PMID: 31473283 DOI: 10.1016/j.bbr.2019.112186] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 12/22/2022]
Abstract
In depression, symptoms range from loss of motivation and energy to suicidal thoughts. Moreover, in depression alterations might be also observed in the sleep-wake cycle and in the daily rhythms of hormonal (e.g., cortisol, melatonin) secretion. Both, the sleep-wake cycle and hormonal rhythms, are regulated by the internal biological clock within the hypothalamic suprachiasmatic nucleus (SCN). Therefore, a dysregulation of the internal mechanism of the SCN might lead in the disturbance of temporal physiology and depression. Hence, circadian symptoms in mood disorders can be used as important biomarkers for the prevention and treatment of depression. Disruptions of daily rhythms in physiology and behavior are also observed in animal models of depression, giving thus an important tool of research for the understanding of the circadian mechanisms implicated in mood disorders. This review discusses the alterations of daily rhythms in depression, and how circadian perturbations might lead in mood changes and depressive-like behavior in humans and rodents respectively. The use of animal models with circadian disturbances and depressive-like behaviors will help to understand the central timing mechanisms underlying depression, and how treating the biological clock(s) it may be possible to improve mood.
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Affiliation(s)
- Jorge Mendoza
- Institute of Cellular and Integrative Neurosciences, CNRS UPR-3212 University of Strasbourg, 8 allée du Général Rouvillois, 67000, Strasbourg, France.
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475
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Webler FS, Spitschan M, Foster RG, Andersen M, Peirson SN. What is the 'spectral diet' of humans? Curr Opin Behav Sci 2019; 30:80-86. [PMID: 31431907 PMCID: PMC6701986 DOI: 10.1016/j.cobeha.2019.06.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Our visual perception of the world — seeing form and colour or navigating the environment — depends on the interaction of light and matter in the environment. Light also has a more fundamental role in regulating rhythms in physiology and behaviour, as well as in the acute secretion of hormones such as melatonin and changes in alertness, where light exposure at short-time, medium-time and long-time scales has different effects on these visual and non-visual functions. Yet patterns of light exposure in the real world are inherently messy: we move in and out of buildings and are therefore exposed to mixtures of artificial and natural light, and the physical makeup of our environment can also drastically alter the spectral composition and spatial distribution of the emitted light. In spatial vision, the examination of natural image statistics has proven to be an important driver in research. Here, we expand this concept to the spectral domain and develop the concept of the ‘spectral diet’ of humans.
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Affiliation(s)
- Forrest S Webler
- Laboratory of Integrated Performance In Design (LIPID), School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Manuel Spitschan
- Department of Experimental Psychology, University of Oxford, United Kingdom.,Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Switzerland.,Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Switzerland
| | - Russell G Foster
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom
| | - Marilyne Andersen
- Laboratory of Integrated Performance In Design (LIPID), School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom
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476
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Cederroth CR, Albrecht U, Bass J, Brown SA, Dyhrfjeld-Johnsen J, Gachon F, Green CB, Hastings MH, Helfrich-Förster C, Hogenesch JB, Lévi F, Loudon A, Lundkvist GB, Meijer JH, Rosbash M, Takahashi JS, Young M, Canlon B. Medicine in the Fourth Dimension. Cell Metab 2019; 30:238-250. [PMID: 31390550 PMCID: PMC6881776 DOI: 10.1016/j.cmet.2019.06.019] [Citation(s) in RCA: 230] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/08/2019] [Accepted: 06/27/2019] [Indexed: 12/21/2022]
Abstract
The importance of circadian biology has rarely been considered in pre-clinical studies, and even more when translating to the bedside. Circadian biology is becoming a critical factor for improving drug efficacy and diminishing drug toxicity. Indeed, there is emerging evidence showing that some drugs are more effective at nighttime than daytime, whereas for others it is the opposite. This suggests that the biology of the target cell will determine how an organ will respond to a drug at a specific time of the day, thus modulating pharmacodynamics. Thus, it is now time that circadian factors become an integral part of translational research.
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Affiliation(s)
- Christopher R Cederroth
- Experimental Audiology, Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Urs Albrecht
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg, Switzerland
| | - Joseph Bass
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Steven A Brown
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | | | - Frederic Gachon
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Carla B Green
- Department of Neuroscience, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Michael H Hastings
- Medical Research Council (MRC) Laboratory of Molecular Biology, Cambridge, UK
| | - Charlotte Helfrich-Förster
- Neurobiology and Genetics, Biocenter, Theodor-Boveri Institute, University of Würzburg, Würzburg, Germany
| | - John B Hogenesch
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Francis Lévi
- Cancer Chronotherapy Team, School of Medicine, University of Warwick, Coventry, UK; Warwick University on "Personalized Cancer Chronotherapeutics through System Medicine" (C2SysMed), European Associated Laboratory of the Unité Mixte de Recherche Scientifique 935, Institut National de la Santé et de la Recherche Médicale and Paris-Sud University, Villejuif, France; Department of Medical Oncology, Paul Brousse Hospital, Assistance Publique-Hopitaux de Paris, 94800 Villejuif, France
| | - Andrew Loudon
- School of Medicine, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | | | - Johanna H Meijer
- Department of Neurophysiology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands
| | - Michael Rosbash
- Department of Biology, Howard Hughes Medical Institute and National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02453, USA
| | - Joseph S Takahashi
- Howard Hughes Medical Institute, Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Michael Young
- Laboratory of Genetics, The Rockefeller University, New York, NY 10065, USA
| | - Barbara Canlon
- Experimental Audiology, Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden.
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477
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Sulli G, Lam MTY, Panda S. Interplay between Circadian Clock and Cancer: New Frontiers for Cancer Treatment. Trends Cancer 2019; 5:475-494. [PMID: 31421905 DOI: 10.1016/j.trecan.2019.07.002] [Citation(s) in RCA: 255] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 07/07/2019] [Accepted: 07/08/2019] [Indexed: 12/23/2022]
Abstract
Circadian clocks constitute the evolutionary molecular machinery that dictates the temporal regulation of physiology to maintain homeostasis. Disruption of the circadian rhythm plays a key role in tumorigenesis and facilitates the establishment of cancer hallmarks. Conversely, oncogenic processes directly weaken circadian rhythms. Pharmacological modulation of core clock genes is a new approach in cancer therapy. The integration of circadian biology into cancer research offers new options for making cancer treatment more effective, encompassing the prevention, diagnosis, and treatment of this devastating disease. This review highlights the role of the circadian clock in tumorigenesis and cancer hallmarks, and discusses how pharmacological modulation of circadian clock genes can lead to new therapeutic options.
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Affiliation(s)
- Gabriele Sulli
- The Salk Institute for Biological Studies, La Jolla, CA, USA; Department of Medicine, Division of Regenerative Medicine, Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA; Scintillon Institute, San Diego, CA 92121, USA.
| | - Michael Tun Yin Lam
- The Salk Institute for Biological Studies, La Jolla, CA, USA; Division of Pulmonary, Critical Care and Sleep Medicine, University of California San Diego, 9300 Campus Point Drive, La Jolla, CA 92037, USA
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478
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Kim YB, Colwell CS, Kim YI. Long-term ionic plasticity of GABAergic signalling in the hypothalamus. J Neuroendocrinol 2019; 31:e12753. [PMID: 31166034 DOI: 10.1111/jne.12753] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 05/24/2019] [Accepted: 06/03/2019] [Indexed: 12/23/2022]
Abstract
The hypothalamus contains a number of nuclei that subserve a variety of functions, including generation of circadian rhythms, regulation of hormone secretion and maintenance of homeostatic levels for a variety of physiological parameters. Within the hypothalamus, γ-amino-butyric acid (GABA) is one of the major neurotransmitters responsible for cellular communication. Although GABA most commonly serves as an inhibitory neurotransmitter, a growing body of evidence indicates that it can evoke post-synaptic excitation as a result of the active regulation of intracellular chloride concentration. In this review, we consider the evidence for this ionic plasticity of GABAergic synaptic transmission in five distinct cases in hypothalamic cell populations. We argue that this plasticity serves as part of the functional response to or is at least associated with dehydration, lactation, hypertension and stress. As such, GABA excitation should be considered as part of the core homeostatic mechanisms of the hypothalamus.
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Affiliation(s)
- Young-Beom Kim
- Department of Physiology, Korea University College of Medicine, Seoul, Korea
- Neuroscience Research Institute, Korea University, Seoul, Korea
| | - Christopher S Colwell
- Department of Psychiatry and Biobehavioral Sciences, UCLA School of Medicine, Los Angeles, CA, USA
| | - Yang In Kim
- Department of Physiology, Korea University College of Medicine, Seoul, Korea
- Neuroscience Research Institute, Korea University, Seoul, Korea
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479
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Brancaccio M, Edwards MD, Patton AP, Smyllie NJ, Chesham JE, Maywood ES, Hastings MH. Cell-autonomous clock of astrocytes drives circadian behavior in mammals. Science 2019; 363:187-192. [PMID: 30630934 DOI: 10.1126/science.aat4104] [Citation(s) in RCA: 219] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 11/02/2018] [Indexed: 12/16/2022]
Abstract
Circadian (~24-hour) rhythms depend on intracellular transcription-translation negative feedback loops (TTFLs). How these self-sustained cellular clocks achieve multicellular integration and thereby direct daily rhythms of behavior in animals is largely obscure. The suprachiasmatic nucleus (SCN) is the fulcrum of this pathway from gene to cell to circuit to behavior in mammals. We describe cell type-specific, functionally distinct TTFLs in neurons and astrocytes of the SCN and show that, in the absence of other cellular clocks, the cell-autonomous astrocytic TTFL alone can drive molecular oscillations in the SCN and circadian behavior in mice. Astrocytic clocks achieve this by reinstating clock gene expression and circadian function of SCN neurons via glutamatergic signals. Our results demonstrate that astrocytes can autonomously initiate and sustain complex mammalian behavior.
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Affiliation(s)
- Marco Brancaccio
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
| | - Mathew D Edwards
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Andrew P Patton
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Nicola J Smyllie
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Johanna E Chesham
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Elizabeth S Maywood
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Michael H Hastings
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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480
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Lugena AB, Zhang Y, Menet JS, Merlin C. Genome-wide discovery of the daily transcriptome, DNA regulatory elements and transcription factor occupancy in the monarch butterfly brain. PLoS Genet 2019; 15:e1008265. [PMID: 31335862 PMCID: PMC6677324 DOI: 10.1371/journal.pgen.1008265] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 08/02/2019] [Accepted: 06/21/2019] [Indexed: 12/20/2022] Open
Abstract
The Eastern North American monarch butterfly, Danaus plexippus, is famous for its spectacular seasonal long-distance migration. In recent years, it has also emerged as a novel system to study how animal circadian clocks keep track of time and regulate ecologically relevant daily rhythmic activities and seasonal behavioral outputs. However, unlike in Drosophila and the mouse, little work has been undertaken in the monarch to identify rhythmic genes at the genome-wide level and elucidate the regulation of their diurnal expression. Here, we used RNA-sequencing and Assay for Transposase-Accessible Chromatin (ATAC)-sequencing to profile the diurnal transcriptome, open chromatin regions, and transcription factor (TF) footprints in the brain of wild-type monarchs and of monarchs with impaired clock function, including Cryptochrome 2 (Cry2), Clock (Clk), and Cycle-like loss-of-function mutants. We identified 217 rhythmically expressed genes in the monarch brain; many of them were involved in the regulation of biological processes key to brain function, such as glucose metabolism and neurotransmission. Surprisingly, we found no significant time-of-day and genotype-dependent changes in chromatin accessibility in the brain. Instead, we found the existence of a temporal regulation of TF occupancy within open chromatin regions in the vicinity of rhythmic genes in the brains of wild-type monarchs, which is disrupted in clock deficient mutants. Together, this work identifies for the first time the rhythmic genes and modes of regulation by which diurnal transcription rhythms are regulated in the monarch brain. It also illustrates the power of ATAC-sequencing to profile genome-wide regulatory elements and TF binding in a non-model organism for which TF-specific antibodies are not yet available. With a rich biology that includes a clock-regulated migratory behavior and a circadian clock possessing mammalian clock orthologues, the monarch butterfly is an unconventional system with broad appeal to study circadian and seasonal rhythms. While clockwork mechanisms and rhythmic behavioral outputs have been studied in this species, the rhythmic genes that regulate rhythmic daily and seasonal activities remain largely unknown. Likewise, the mechanisms regulating rhythmic gene expression have not been explored in the monarch. Here, we applied genome-wide sequencing approaches to identify genes with rhythmic diurnal expression in the monarch brain, revealing the coordination of key pathways for brain function. We also identified the monarch brain open chromatin regions and provide evidence that regulation of rhythmic gene expression does not occur through temporal regulation of chromatin opening but rather by the time-of-day dependent binding of transcription factors in cis-regulatory elements. Together, our data extend our knowledge of the molecular rhythmic pathways, which may prove important in understanding the mechanisms underlying the daily and seasonal biology of the migratory monarch butterflies.
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Affiliation(s)
- Aldrin B. Lugena
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
| | - Ying Zhang
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
| | - Jerome S. Menet
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
| | - Christine Merlin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
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481
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Ikeda R, Tsuchiya Y, Koike N, Umemura Y, Inokawa H, Ono R, Inoue M, Sasawaki Y, Grieten T, Okubo N, Ikoma K, Fujiwara H, Kubo T, Yagita K. REV-ERBα and REV-ERBβ function as key factors regulating Mammalian Circadian Output. Sci Rep 2019; 9:10171. [PMID: 31308426 PMCID: PMC6629614 DOI: 10.1038/s41598-019-46656-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 06/28/2019] [Indexed: 01/27/2023] Open
Abstract
The circadian clock regulates behavioural and physiological processes in a 24-h cycle. The nuclear receptors REV-ERBα and REV-ERBβ are involved in the cell-autonomous circadian transcriptional/translational feedback loops as transcriptional repressors. A number of studies have also demonstrated a pivotal role of REV-ERBs in regulation of metabolic, neuronal, and inflammatory functions including bile acid metabolism, lipid metabolism, and production of inflammatory cytokines. Given the multifunctional role of REV-ERBs, it is important to elucidate the mechanism through which REV-ERBs exert their functions. To this end, we established a Rev-erbα/Rev-erbβ double-knockout mouse embryonic stem (ES) cell model and analyzed the circadian clock and clock-controlled output gene expressions. A comprehensive mRNA-seq analysis revealed that the double knockout of both Rev-erbα and Rev-erbβ does not abrogate expression rhythms of E-box-regulated core clock genes but drastically changes a diverse set of other rhythmically-expressed output genes. Of note, REV-ERBα/β deficiency does not compromise circadian expression rhythms of PER2, while REV-ERB target genes, Bmal1 and Npas2, are significantly upregulated. This study highlight the relevance of REV-ERBs as pivotal output mediators of the mammalian circadian clock.
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Affiliation(s)
- Ryosuke Ikeda
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.,Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yoshiki Tsuchiya
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
| | - Nobuya Koike
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yasuhiro Umemura
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Hitoshi Inokawa
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Ryutaro Ono
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Maho Inoue
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yuh Sasawaki
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Tess Grieten
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Naoki Okubo
- Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Kazuya Ikoma
- Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Hiroyoshi Fujiwara
- Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Toshikazu Kubo
- Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Kazuhiro Yagita
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
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482
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Sato S, Basse AL, Schönke M, Chen S, Samad M, Altıntaş A, Laker RC, Dalbram E, Barrès R, Baldi P, Treebak JT, Zierath JR, Sassone-Corsi P. Time of Exercise Specifies the Impact on Muscle Metabolic Pathways and Systemic Energy Homeostasis. Cell Metab 2019; 30:92-110.e4. [PMID: 31006592 DOI: 10.1016/j.cmet.2019.03.013] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/06/2019] [Accepted: 03/26/2019] [Indexed: 12/11/2022]
Abstract
While the timing of food intake is important, it is unclear whether the effects of exercise on energy metabolism are restricted to unique time windows. As circadian regulation is key to controlling metabolism, understanding the impact of exercise performed at different times of the day is relevant for physiology and homeostasis. Using high-throughput transcriptomic and metabolomic approaches, we identify distinct responses of metabolic oscillations that characterize exercise in either the early rest phase or the early active phase in mice. Notably, glycolytic activation is specific to exercise at the active phase. At the molecular level, HIF1α, a central regulator of glycolysis during hypoxia, is selectively activated in a time-dependent manner upon exercise, resulting in carbohydrate exhaustion, usage of alternative energy sources, and adaptation of systemic energy expenditure. Our findings demonstrate that the time of day is a critical factor to amplify the beneficial impact of exercise on both metabolic pathways within skeletal muscle and systemic energy homeostasis.
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Affiliation(s)
- Shogo Sato
- Center for Epigenetics and Metabolism, INSERM U1233, Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Astrid Linde Basse
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Milena Schönke
- Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Siwei Chen
- Institute for Genomics and Bioinformatics, University of California, Irvine, Irvine, CA, USA
| | - Muntaha Samad
- Institute for Genomics and Bioinformatics, University of California, Irvine, Irvine, CA, USA
| | - Ali Altıntaş
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Rhianna C Laker
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Emilie Dalbram
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Romain Barrès
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Pierre Baldi
- Institute for Genomics and Bioinformatics, University of California, Irvine, Irvine, CA, USA
| | - Jonas T Treebak
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Juleen R Zierath
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark; Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden; Department of Physiology and Pharmacology, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Paolo Sassone-Corsi
- Center for Epigenetics and Metabolism, INSERM U1233, Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA.
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483
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Daut RA, Fonken LK. Circadian regulation of depression: A role for serotonin. Front Neuroendocrinol 2019; 54:100746. [PMID: 31002895 PMCID: PMC9826732 DOI: 10.1016/j.yfrne.2019.04.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/13/2019] [Accepted: 04/15/2019] [Indexed: 01/11/2023]
Abstract
Synchronizing circadian (24 h) rhythms in physiology and behavior with the environmental light-dark cycle is critical for maintaining optimal health. Dysregulation of the circadian system increases susceptibility to numerous pathological conditions including major depressive disorder. Stress is a common etiological factor in the development of depression and the circadian system is highly interconnected to stress-sensitive neurotransmitter systems such as the serotonin (5-hydroxytryptamine, 5-HT) system. Thus, here we propose that stress-induced perturbation of the 5-HT system disrupts circadian processes and increases susceptibility to depression. In this review, we first provide an overview of the basic components of the circadian system. Next, we discuss evidence that circadian dysfunction is associated with changes in mood in humans and rodent models. Finally, we provide evidence that 5-HT is a critical factor linking dysregulation of the circadian system and mood. Determining how these two systems interact may provide novel therapeutic targets for depression.
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Affiliation(s)
- Rachel A Daut
- Department of Psychology and Neuroscience, Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Laura K Fonken
- University of Texas at Austin, Division of Pharmacology and Toxicology, Austin, TX 78712, USA.
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484
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Jiao X, Wu M, Lu D, Gu J, Li Z. Transcriptional Profiling of Daily Patterns of mRNA Expression in the C57BL/6J Mouse Cornea. Curr Eye Res 2019; 44:1054-1066. [PMID: 31136724 DOI: 10.1080/02713683.2019.1625408] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Purpose: The purpose of this study was to determine how the transcriptome of the murine cornea adapts to diurnal changes in physiology. Methods: C57BL/6J mice were maintained under a 12-h light/12-h dark (LD) cycle for two weeks. Corneas were collected from euthanized mice at Zeitgeber time (ZT) 0, 3, 6, 9, 12, 15, 18, and 21. Total RNA was extracted and subjected to RNA sequencing (RNA-Seq). A JTK_CYCLE algoithm and other software tools were used to analyze the transcriptional data to determine the periodicity, rhythmicity, and amplitude of the transcripts. Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyze the enrichment of cycling transcripts. Results: Approximately 24% of the total transcripts from the murine corneal genome were rhythmically expressed over an LD cycle. GO analysis showed that these cycling genes are primarily involved in cellular and metabolic processes. A KEGG pathway analysis identified 6 branches and 44 pathways that encode the gene outputs necessary for basic cellular functions and processes. More importantly, most of the rhythmic genes between the day and night are enriched in their own unique pathways in addition to some common pathways. Furthermore, most of the rhythmic gene expression was concentrated in the 12-h and 24-h periods. A comparative analysis of GO and KEGG showed large differences in metabolic processes, but not cellular processes. Finally, the murine cornea also rhythmically expressed 11 canonical components of circadian clock genes over an LD cycle at the transcriptional level. Conclusions: One fourth of the corneal transcriptome follows a rhythmic expression pattern involved in basic molecular and cellular mechanisms. This implies that the time of day contributes significantly to the overall temporal organization of the corneal transcriptome.
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Affiliation(s)
- Xinwei Jiao
- Henan Provincial People's Hospital and People's Hospital of Henan University, Henan Eye Institute, Henan Eye Hospital , Zhengzhou , China
| | - Mingjuan Wu
- International Ocular Surface Research Center and Institute of Ophthalmology, Key Laboratory for Regenerative Medicine, Jinan University Medical School , Guangzhou , China
| | - Dingli Lu
- Henan Provincial People's Hospital and People's Hospital of Henan University, Henan Eye Institute, Henan Eye Hospital , Zhengzhou , China
| | - Jianqin Gu
- Henan Provincial People's Hospital and People's Hospital of Henan University, Henan Eye Institute, Henan Eye Hospital , Zhengzhou , China
| | - Zhijie Li
- Henan Provincial People's Hospital and People's Hospital of Henan University, Henan Eye Institute, Henan Eye Hospital , Zhengzhou , China.,International Ocular Surface Research Center and Institute of Ophthalmology, Key Laboratory for Regenerative Medicine, Jinan University Medical School , Guangzhou , China
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485
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Filipovská E, Červená K, Moravcová S, Novotný J, Kyclerová H, Spišská V, Pačesová D, Bendová Z. The effect of the cannabinoid receptor agonist and antagonist on the light-induced changes in the suprachiasmatic nucleus of rats. Neurosci Lett 2019; 703:49-52. [PMID: 30885633 DOI: 10.1016/j.neulet.2019.03.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/28/2019] [Accepted: 03/13/2019] [Indexed: 11/20/2022]
Abstract
The CB1 cannabinoid receptors have been found in the rodent suprachiasmatic nucleus, and their activation suppresses the light-induced phase shift in locomotor rhythmicity of mice and hamsters. Here, we show that the CB1 receptor agonist CP55940 significantly attenuates the light-induced phase delay in rats as well. Furthermore, it blocks the light induction of c-Fos and light-induced downregulation of pERK1/2 in the SCN, and the CB1 antagonist AM251 prevents the photic induction of pERK1/2 and reduces pGSK3β after photic stimulation. Our data suggest that the modulation of the cannabinoid receptor activity may affect the photic entrainment via the setting of the SCN sensitivity to light.
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Affiliation(s)
- Eva Filipovská
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Kateřina Červená
- Faculty of Science, Charles University, Prague, Czech Republic; National Institute of Mental Health, Klecany, Czech Republic
| | - Simona Moravcová
- Faculty of Science, Charles University, Prague, Czech Republic; National Institute of Mental Health, Klecany, Czech Republic
| | - Jiří Novotný
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Hana Kyclerová
- Faculty of Science, Charles University, Prague, Czech Republic
| | | | - Dominika Pačesová
- Faculty of Science, Charles University, Prague, Czech Republic; National Institute of Mental Health, Klecany, Czech Republic
| | - Zdeňka Bendová
- Faculty of Science, Charles University, Prague, Czech Republic; National Institute of Mental Health, Klecany, Czech Republic.
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486
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Calcium Signaling Pathways: Key Pathways in the Regulation of Obesity. Int J Mol Sci 2019; 20:ijms20112768. [PMID: 31195699 PMCID: PMC6600289 DOI: 10.3390/ijms20112768] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 05/29/2019] [Accepted: 05/31/2019] [Indexed: 02/07/2023] Open
Abstract
Nowadays, high epidemic obesity-triggered hypertension and diabetes seriously damage social public health. There is now a general consensus that the body's fat content exceeding a certain threshold can lead to obesity. Calcium ion is one of the most abundant ions in the human body. A large number of studies have shown that calcium signaling could play a major role in increasing energy consumption by enhancing the metabolism and the differentiation of adipocytes and reducing food intake through regulating neuronal excitability, thereby effectively decreasing the occurrence of obesity. In this paper, we review multiple calcium signaling pathways, including the IP3 (inositol 1,4,5-trisphosphate)-Ca2+ (calcium ion) pathway, the p38-MAPK (mitogen-activated protein kinase) pathway, and the calmodulin binding pathway, which are involved in biological clock, intestinal microbial activity, and nerve excitability to regulate food intake, metabolism, and differentiation of adipocytes in mammals, resulting in the improvement of obesity.
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487
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Chok KC, Ng CH, Koh RY, Ng KY, Chye SM. The potential therapeutic actions of melatonin in colorectal cancer. Horm Mol Biol Clin Investig 2019; 39:hmbci-2019-0001. [DOI: 10.1515/hmbci-2019-0001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 04/01/2019] [Indexed: 12/24/2022]
Abstract
Abstract
Colorectal cancer (CRC) is the third most common cancer and lethal disease worldwide. Melatonin, an indoleamine produced in pineal gland, shows anticancer effects on a variety of cancers, especially CRC. After clarifying the pathophysiology of CRC, the association of circadian rhythm with CRC, and the relationship between shift work and the incidence of CRC is reviewed. Next, we review the role of melatonin receptors in CRC and the relationship between inflammation and CRC. Also included is a discussion of the mechanism of gene regulation, control of cell proliferation, apoptosis, autophagy, antiangiogenesis and immunomodulation in CRC by melatonin. A review of the drug synergy of melatonin with other anticancer drugs suggests its usefulness in combination therapy. In summary, the information compiled may serve as comprehensive reference for the various mechanisms of action of melatonin against CRC, and as a guide for the design of future experimental research and for advancing melatonin as a therapeutic agent for CRC.
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Affiliation(s)
- Kian Chung Chok
- School of Health Sciences, International Medical University , Kuala Lumpur , Malaysia
| | - Chew Hee Ng
- School of Pharmacy, International Medical University , Kuala Lumpur , Malaysia
| | - Rhun Yian Koh
- School of Health Sciences, International Medical University , Kuala Lumpur , Malaysia
| | - Khuen Yen Ng
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia , Selangor , Malaysia
| | - Soi Moi Chye
- School of Health Sciences, International Medical University , Kuala Lumpur , Malaysia , Phone: +6032731 7220; Fax: +60386567229
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488
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Pacheco-Bernal I, Becerril-Pérez F, Aguilar-Arnal L. Circadian rhythms in the three-dimensional genome: implications of chromatin interactions for cyclic transcription. Clin Epigenetics 2019; 11:79. [PMID: 31092281 PMCID: PMC6521413 DOI: 10.1186/s13148-019-0677-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 04/29/2019] [Indexed: 12/20/2022] Open
Abstract
Circadian rhythms orchestrate crucial physiological functions and behavioral aspects around a day in almost all living forms. The circadian clock is a time tracking system that permits organisms to predict and anticipate periodic environmental fluctuations. The circadian system is hierarchically organized, and a master pacemaker located in the brain synchronizes subsidiary clocks in the rest of the organism. Adequate synchrony between central and peripheral clocks ensures fitness and potentiates a healthy state. Conversely, disruption of circadian rhythmicity is associated with metabolic diseases, psychiatric disorders, or cancer, amongst other pathologies. Remarkably, the molecular machinery directing circadian rhythms consists of an intricate network of feedback loops in transcription and translation which impose 24-h cycles in gene expression across all tissues. Interestingly, the molecular clock collaborates with multitude of epigenetic remodelers to fine tune transcriptional rhythms in a tissue-specific manner. Very exciting research demonstrate that three-dimensional properties of the genome have a regulatory role on circadian transcriptional rhythmicity, from bacteria to mammals. Unexpectedly, highly dynamic long-range chromatin interactions have been revealed during the circadian cycle in mammalian cells, where thousands of regulatory elements physically interact with promoter regions every 24 h. Molecular mechanisms directing circadian dynamics on chromatin folding are emerging, and the coordinated action between the core clock and epigenetic remodelers appears to be essential for these movements. These evidences reveal a critical epigenetic regulatory layer for circadian rhythms and pave the way to uncover molecular mechanisms triggering pathological states associated to circadian misalignment.
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Affiliation(s)
- Ignacio Pacheco-Bernal
- Instituto de Investigaciones Biomédicas, Departamento de Biología Celular y Fisiología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Fernando Becerril-Pérez
- Instituto de Investigaciones Biomédicas, Departamento de Biología Celular y Fisiología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Lorena Aguilar-Arnal
- Instituto de Investigaciones Biomédicas, Departamento de Biología Celular y Fisiología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
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489
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Circadian neurogenetics of mood disorders. Cell Tissue Res 2019; 377:81-94. [DOI: 10.1007/s00441-019-03033-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 04/09/2019] [Indexed: 02/07/2023]
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490
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Abstract
Endogenous central and peripheral circadian oscillators are key to organizing multiple aspects of mammalian physiology; this clock tracks the day-night cycle and governs behavioral and physiologic rhythmicity. Flexibility in the timing and duration of sleep and wakefulness, critical to the survival of species, is the result of a complex, dynamic interaction between 2 regulatory processes: the clock and a homeostatic drive that increases with wake duration and decreases during sleep. When circadian rhythmicity and sleep homeostasis are misaligned-as in shifted schedules, time zone transitions, aging, or disease-sleep, metabolic, and other disorders may ensue.
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491
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Kolbe I, Brehm N, Oster H. Interplay of central and peripheral circadian clocks in energy metabolism regulation. J Neuroendocrinol 2019; 31:e12659. [PMID: 30415480 DOI: 10.1111/jne.12659] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/01/2018] [Accepted: 11/05/2018] [Indexed: 12/11/2022]
Abstract
Metabolic health founds on a homeostatic balance that has to integrate the daily changes of rest/activity and feeding/fasting cycles. A network of endogenous 24-hour circadian clocks helps to anticipate daily recurring events and adjust physiology and behavioural functions accordingly. Circadian clocks are self-sustained cellular oscillators based on a set of clock genes/proteins organised in interlocked transcriptional-translational feedback loops. The body's clocks need to be regularly reset and synchronised with each other to achieve coherent rhythmic output signals. This synchronisation is achieved by interplay of a master clock, which resides in the suprachiasmatic nucleus, and peripheral tissue clocks. This clock network is reset by time signals such as the light/dark cycle, food intake and activity. The balanced interplay of clocks is easily disturbed in modern society by shiftwork or high-energy diets, which may further promote the development of metabolic disorders. In this review, we summarise the current model of central-peripheral clock interaction in metabolic health. Different established mouse models for central or peripheral clock disruption and their metabolic phenotypes are compared and the possible relevance of clock network interaction for the development of therapeutic approaches in humans is discussed.
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Affiliation(s)
- Isa Kolbe
- Institute of Neurobiology, University of Lubeck, Lubeck, Germany
| | - Niklas Brehm
- Institute of Neurobiology, University of Lubeck, Lubeck, Germany
| | - Henrik Oster
- Institute of Neurobiology, University of Lubeck, Lubeck, Germany
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492
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El Cheikh Hussein L, Mollard P, Bonnefont X. Molecular and Cellular Networks in The Suprachiasmatic Nuclei. Int J Mol Sci 2019; 20:ijms20082052. [PMID: 31027315 PMCID: PMC6514755 DOI: 10.3390/ijms20082052] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/20/2022] Open
Abstract
Why do we experience the ailments of jetlag when we travel across time zones? Why is working night-shifts so detrimental to our health? In other words, why can’t we readily choose and stick to non-24 h rhythms? Actually, our daily behavior and physiology do not simply result from the passive reaction of our organism to the external cycle of days and nights. Instead, an internal clock drives the variations in our bodily functions with a period close to 24 h, which is supposed to enhance fitness to regular and predictable changes of our natural environment. This so-called circadian clock relies on a molecular mechanism that generates rhythmicity in virtually all of our cells. However, the robustness of the circadian clock and its resilience to phase shifts emerge from the interaction between cell-autonomous oscillators within the suprachiasmatic nuclei (SCN) of the hypothalamus. Thus, managing jetlag and other circadian disorders will undoubtedly require extensive knowledge of the functional organization of SCN cell networks. Here, we review the molecular and cellular principles of circadian timekeeping, and their integration in the multi-cellular complexity of the SCN. We propose that new, in vivo imaging techniques now enable to address these questions directly in freely moving animals.
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Affiliation(s)
- Lama El Cheikh Hussein
- Institut de Génomique Fonctionnelle (IGF), University Montpellier, CNRS, INSERM, 34094 Montpellier, France.
| | - Patrice Mollard
- Institut de Génomique Fonctionnelle (IGF), University Montpellier, CNRS, INSERM, 34094 Montpellier, France.
| | - Xavier Bonnefont
- Institut de Génomique Fonctionnelle (IGF), University Montpellier, CNRS, INSERM, 34094 Montpellier, France.
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493
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2,3,7,8-Tetrachlorodibenzo-p-dioxin abolishes circadian regulation of hepatic metabolic activity in mice. Sci Rep 2019; 9:6514. [PMID: 31015483 PMCID: PMC6478849 DOI: 10.1038/s41598-019-42760-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 04/05/2019] [Indexed: 12/19/2022] Open
Abstract
Aryl hydrocarbon receptor (AhR) activation is reported to alter the hepatic expression of circadian clock regulators, however the impact on clock-controlled metabolism has not been thoroughly investigated. This study examines the effects of AhR activation on hepatic transcriptome and metabolome rhythmicity in male C57BL/6 mice orally gavaged with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) every 4 days for 28 days. TCDD diminished the rhythmicity of several core clock regulators (e.g. Arntl, Clock, Nr1d1, Per1, Cry1, Nfil3) in a dose-dependent manner, involving either a ≥ 3.3-fold suppression in amplitude or complete loss of oscillation. Accordingly, protein levels (ARNTL, REV-ERBα, NFIL3) and genomic binding (ARNTL) of select regulators were reduced and arrhythmic following treatment. As a result, the oscillating expression of 99.6% of 5,636 clock-controlled hepatic genes was abolished including genes associated with the metabolism of lipids, glucose/glycogen, and heme. For example, TCDD flattened expression of the rate-limiting enzymes in both gluconeogenesis (Pck1) and glycogenesis (Gys2), consistent with the depletion and loss of rhythmicity in hepatic glycogen levels. Examination of polar hepatic extracts by untargeted mass spectrometry revealed that virtually all oscillating metabolites lost rhythmicity following treatment. Collectively, these results suggest TCDD disrupted circadian regulation of hepatic metabolism, altering metabolic efficiency and energy storage.
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494
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Bulthuis N, Spontak KR, Kleeman B, Cavanaugh DJ. Neuronal Activity in Non-LNv Clock Cells Is Required to Produce Free-Running Rest:Activity Rhythms in Drosophila. J Biol Rhythms 2019; 34:249-271. [PMID: 30994046 DOI: 10.1177/0748730419841468] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Circadian rhythms in behavior and physiology are produced by central brain clock neurons that can be divided into subpopulations based on molecular and functional characteristics. It has become clear that coherent behavioral rhythms result from the coordinated action of these clock neuron populations, but many questions remain regarding the organizational logic of the clock network. Here we used targeted genetic tools in Drosophila to eliminate either molecular clock function or neuronal activity in discrete clock neuron subsets. We find that neuronal firing is necessary across multiple clock cell populations to produce free-running rhythms of rest and activity. In contrast, such rhythms are much more subtly affected by molecular clock suppression in the same cells. These findings demonstrate that network connectivity can compensate for a lack of molecular oscillations within subsets of clock cells. We further show that small ventrolateral (sLNv) clock neurons, which have been characterized as master pacemakers under free-running conditions, cannot drive rhythms independent of communication between other cells of the clock network. In particular, we pinpoint an essential contribution of the dorsolateral (LNd) clock neurons, and show that manipulations that affect LNd function reduce circadian rhythm strength without affecting molecular cycling in sLNv cells. These results suggest a hierarchical organization in which circadian information is first consolidated among one or more clock cell populations before accessing output pathways that control locomotor activity.
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495
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Gachon F. [Circadian proteomics]. Biol Aujourdhui 2019; 212:55-59. [PMID: 30973132 DOI: 10.1051/jbio/2018025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Indexed: 06/09/2023]
Abstract
Recent development in the proteomic technologies offers new perspectives in circadian biology and in particular the possibility to study post-translational modifications such as phosphorylation and acetylation. Applying in vivo proteomics on whole liver or on nuclear extracts, we were able to characterize the rhythmic liver proteome with unprecedented coverage. It allows the characterization of new rhythmic processes such as protein secretion, ribosome biogenesis, DNA repair, and polyploidy. In addition, the analysis of rhythmic post-translational modifications helps to understand the signal pathways involved and their consequences on hepatic metabolism.
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Affiliation(s)
- Frédéric Gachon
- Institut de Bioingénierie, Faculté des Sciences de la Vie, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Suisse - Département de Pharmacologie et Toxicologie, Université de Lausanne, 1005 Lausanne, Suisse
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496
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Song SO, He K, Narla RR, Kang HG, Ryu HU, Boyko EJ. Metabolic Consequences of Obstructive Sleep Apnea Especially Pertaining to Diabetes Mellitus and Insulin Sensitivity. Diabetes Metab J 2019; 43:144-155. [PMID: 30993938 PMCID: PMC6470104 DOI: 10.4093/dmj.2018.0256] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 02/19/2019] [Indexed: 01/25/2023] Open
Abstract
Obstructive sleep apnea (OSA) and diabetes has been known to be closely related to each other and both diseases impact highly on the public health. There are many evidence of reports that OSA is associated with diabetes with a bidirectional correlation. A possible causal mechanism of OSA to diabetes is intermittent hypoxemia and diabetes to OSA is microvascular complication. However, OSA and diabetes have a high prevalence rate in public and shares the common overlap characteristic and risk factors such as age, obesity, and metabolic syndrome that make it difficult to establish the exact pathophysiologic mechanism between them. In addition, studies demonstrating that treatment of OSA may help prevent diabetes or improve glycemic control have not shown convincing result but have become a great field of interest research. This review outlines the bidirectional correlation between OSA and diabetes and explore the pathophysiologic mechanisms by approaching their basic etiologies.
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Affiliation(s)
- Sun Ok Song
- Epidemiologic Research and Information Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
- Department of Endocrinology and Metabolism, National Health Insurance Service Ilsan Hospital, Goyang, Korea
| | - Ken He
- Sleep Medicine Section, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - Radhika R Narla
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Hyun Goo Kang
- Department of Neurology, Chonbuk National University Medical School, Jeonju, Korea
| | - Han Uk Ryu
- Department of Neurology, Chonbuk National University Medical School, Jeonju, Korea.
| | - Edward J Boyko
- Epidemiologic Research and Information Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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497
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Hodges EL, Ashpole NM. Aging circadian rhythms and cannabinoids. Neurobiol Aging 2019; 79:110-118. [PMID: 31035036 DOI: 10.1016/j.neurobiolaging.2019.03.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/11/2019] [Accepted: 03/17/2019] [Indexed: 01/04/2023]
Abstract
Numerous aspects of mammalian physiology exhibit cyclic daily patterns known as circadian rhythms. However, studies in aged humans and animals indicate that these physiological rhythms are not consistent throughout the life span. The simultaneous development of disrupted circadian rhythms and age-related impairments suggests a shared mechanism, which may be amenable to therapeutic intervention. Recently, the endocannabinoid system has emerged as a complex signaling network, which regulates numerous aspects of circadian physiology relevant to the neurobiology of aging. Agonists of cannabinoid receptor-1 (CB1) have consistently been shown to decrease neuronal activity, core body temperature, locomotion, and cognitive function. Paradoxically, several lines of evidence now suggest that very low doses of cannabinoids are beneficial in advanced age. One potential explanation for this phenomenon is that these drugs exhibit hormesis-a biphasic dose-response wherein low doses produce the opposite effects of higher doses. Therefore, it is important to determine the dose-, age-, and time-dependent effects of these substances on the regulation of circadian rhythms and other processes dysregulated in aging. This review highlights 3 fields-biological aging, circadian rhythms, and endocannabinoid signaling-to critically assess the therapeutic potential of endocannabinoid modulation in aged individuals. If the hormetic properties of exogenous cannabinoids are confirmed, we conclude that precise administration of these compounds may bidirectionally entrain central and peripheral circadian clocks and benefit multiple aspects of aging physiology.
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Affiliation(s)
- Erik L Hodges
- Pharmacology Division, Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, Oxford, MS, USA
| | - Nicole M Ashpole
- Pharmacology Division, Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, Oxford, MS, USA.
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498
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Hastings MH, Maywood ES, Brancaccio M. The Mammalian Circadian Timing System and the Suprachiasmatic Nucleus as Its Pacemaker. BIOLOGY 2019; 8:E13. [PMID: 30862123 PMCID: PMC6466121 DOI: 10.3390/biology8010013] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 11/16/2022]
Abstract
The past twenty years have witnessed the most remarkable breakthroughs in our understanding of the molecular and cellular mechanisms that underpin circadian (approximately one day) time-keeping. Across model organisms in diverse taxa: cyanobacteria (Synechococcus), fungi (Neurospora), higher plants (Arabidopsis), insects (Drosophila) and mammals (mouse and humans), a common mechanistic motif of delayed negative feedback has emerged as the Deus ex machina for the cellular definition of ca. 24 h cycles. This review will consider, briefly, comparative circadian clock biology and will then focus on the mammalian circadian system, considering its molecular genetic basis, the properties of the suprachiasmatic nucleus (SCN) as the principal circadian clock in mammals and its role in synchronising a distributed peripheral circadian clock network. Finally, it will consider new directions in analysing the cell-autonomous and circuit-level SCN clockwork and will highlight the surprising discovery of a central role for SCN astrocytes as well as SCN neurons in controlling circadian behaviour.
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Affiliation(s)
- Michael H Hastings
- MRC Laboratory of Molecular Biology, Division of Neurobiology, CB2 0QH Cambridge, UK.
| | - Elizabeth S Maywood
- MRC Laboratory of Molecular Biology, Division of Neurobiology, CB2 0QH Cambridge, UK.
| | - Marco Brancaccio
- UK Dementia Research Institute at Imperial College London, Division of Brain Sciences, Department of Medicine, W12 0NN London, UK.
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499
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Baschieri F, Cortelli P. Circadian rhythms of cardiovascular autonomic function: Physiology and clinical implications in neurodegenerative diseases. Auton Neurosci 2019; 217:91-101. [DOI: 10.1016/j.autneu.2019.01.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/31/2019] [Accepted: 01/31/2019] [Indexed: 12/11/2022]
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500
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A saturated reaction in repressor synthesis creates a daytime dead zone in circadian clocks. PLoS Comput Biol 2019; 15:e1006787. [PMID: 30779745 PMCID: PMC6396941 DOI: 10.1371/journal.pcbi.1006787] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 03/01/2019] [Accepted: 01/14/2019] [Indexed: 11/19/2022] Open
Abstract
Negative feedback loops (NFLs) for circadian clocks include light-responsive reactions that allow the clocks to shift their phase depending on the timing of light signals. Phase response curves (PRCs) for light signals in various organisms include a time interval called a dead zone where light signals cause no phase shift during daytime. Although the importance of the dead zone for robust light entrainment is known, how the dead zone arises from the biochemical reactions in an NFL underlying circadian gene expression rhythms remains unclear. In addition, the observation that the light-responsive reactions in the NFL vary between organisms raises the question as to whether the mechanism for dead zone formation is common or distinct between different organisms. Here we reveal by mathematical modeling that the saturation of a biochemical reaction in repressor synthesis in an NFL is a common mechanism of daytime dead zone generation. If light signals increase the degradation of a repressor protein, as in Drosophila, the saturation of repressor mRNA transcription nullifies the effect of light signals, generating a dead zone. In contrast, if light signals induce the transcription of repressor mRNA, as in mammals, the saturation of repressor translation can generate a dead zone by cancelling the influence of excess amount of mRNA induced by light signals. Each of these saturated reactions is located next to the light-responsive reaction in the NFL, suggesting a design principle for daytime dead zone generation. Light-entrainable circadian clocks form behavioral and physiological rhythms in organisms. The light-entrainment properties of these clocks have been studied by measuring phase shifts caused by light pulses administered at different times. The phase response curves of various organisms include a time window called the dead zone where the phase of the clock does not respond to light pulses. However, the mechanism underlying the dead zone generation remains unclear. We show that the saturation of biochemical reactions in feedback loops for circadian oscillations generates a dead zone. The proposed mechanism is generic, as it functions in different models of the circadian clocks and biochemical oscillators. Our analysis indicates that light-entrainment properties are determined by biochemical reactions at the single-cell level.
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