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Calligaro H, Shoghi A, Chen X, Kim KY, Yu HL, Khov B, Finander B, Le H, Ellisman MH, Panda S. Ultrastructure of Synaptic Connectivity within Subregions of the Suprachiasmatic Nucleus Revealed by a Genetically Encoded Tag and Serial Blockface Electron Microscopy. eNeuro 2023; 10:ENEURO.0227-23.2023. [PMID: 37500494 PMCID: PMC10449486 DOI: 10.1523/eneuro.0227-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 07/01/2023] [Indexed: 07/29/2023] Open
Abstract
The hypothalamic suprachiasmatic nucleus (SCN) is the central circadian pacemaker in vertebrates. The SCN receives photic information exclusively through melanopsin-expressing retinal ganglion cells (mRGCs) to synchronize circadian rhythms with the environmental light cycles. The SCN is composed of two major peptidergic neuron types in the core and shell regions of the SCN. Determining how mRGCs interact with the network of synaptic connections onto and between SCN neurons is key to understand how light regulates the circadian clock and to elucidate the relevant local circuits within the SCN. To map these connections, we used a newly developed Cre-dependent electron microscopy (EM) reporter, APEX2, to label the mitochondria of mRGC axons. Serial blockface scanning electron microscopy was then used to resolve the fine 3D structure of mRGC axons and synaptic boutons in the SCN of a male mouse. The resulting maps reveal patterns of connectomic organization in the core and shell of the SCN. We show that these regions are composed of different neuronal subtypes and differ with regard to the pattern of mRGC input, as the shell receives denser mRGC synaptic input compared with the core. This finding challenges the present view that photic information coming directly from the retina is received primarily by the core region of the SCN.
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Affiliation(s)
- Hugo Calligaro
- Salk Institute for Biological Studies, La Jolla, CA 92037
| | - Azarin Shoghi
- Salk Institute for Biological Studies, La Jolla, CA 92037
| | - Xinyue Chen
- Salk Institute for Biological Studies, La Jolla, CA 92037
| | - Keun-Young Kim
- Department of Neurosciences, University of California at San Diego School of Medicine, La Jolla, CA 92161
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA 92161
| | - Hsin Liu Yu
- Salk Institute for Biological Studies, La Jolla, CA 92037
| | - Brian Khov
- Salk Institute for Biological Studies, La Jolla, CA 92037
| | | | - Hiep Le
- Salk Institute for Biological Studies, La Jolla, CA 92037
| | - Mark H. Ellisman
- Department of Neurosciences, University of California at San Diego School of Medicine, La Jolla, CA 92161
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA 92161
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2
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Birnie M, Claydon M, Troy O, Flynn B, Yoshimura M, Kershaw Y, Zhao Z, Demski-Allen R, Barker G, Warburton E, Bortolotto Z, Lightman S, Conway-Campbell B. Circadian regulation of hippocampal function is disrupted with corticosteroid treatment. Proc Natl Acad Sci U S A 2023; 120:e2211996120. [PMID: 37023133 PMCID: PMC10104554 DOI: 10.1073/pnas.2211996120] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 02/24/2023] [Indexed: 04/07/2023] Open
Abstract
Disrupted circadian activity is associated with many neuropsychiatric disorders. A major coordinator of circadian biological systems is adrenal glucocorticoid secretion which exhibits a pronounced preawakening peak that regulates metabolic, immune, and cardiovascular processes, as well as mood and cognitive function. Loss of this circadian rhythm during corticosteroid therapy is often associated with memory impairment. Surprisingly, the mechanisms that underlie this deficit are not understood. In this study, in rats, we report that circadian regulation of the hippocampal transcriptome integrates crucial functional networks that link corticosteroid-inducible gene regulation to synaptic plasticity processes via an intrahippocampal circadian transcriptional clock. Further, these circadian hippocampal functions were significantly impacted by corticosteroid treatment delivered in a 5-d oral dosing treatment protocol. Rhythmic expression of the hippocampal transcriptome, as well as the circadian regulation of synaptic plasticity, was misaligned with the natural light/dark circadian-entraining cues, resulting in memory impairment in hippocampal-dependent behavior. These findings provide mechanistic insights into how the transcriptional clock machinery within the hippocampus is influenced by corticosteroid exposure, leading to adverse effects on critical hippocampal functions, as well as identifying a molecular basis for memory deficits in patients treated with long-acting synthetic corticosteroids.
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Affiliation(s)
- Matthew T. Birnie
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
| | - Matthew D. B. Claydon
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Oliver Troy
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
| | - Benjamin P. Flynn
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
| | - Mitsuhiro Yoshimura
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
| | - Yvonne M. Kershaw
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
| | - Zidong Zhao
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
| | - Rebecca C. R. Demski-Allen
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Gareth R. I. Barker
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - E. Clea Warburton
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Zuner A. Bortolotto
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Stafford L. Lightman
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
| | - Becky L. Conway-Campbell
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Faculty of Health Sciences, School of Medicine, University of Bristol, BristolBS1 3NY, United Kingdom
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3
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Schwartz MD, Cambras T, Díez-Noguera A, Campuzano A, Oda GA, Yamazaki S, de la Iglesia HO. Coupling Between Subregional Oscillators Within the Suprachiasmatic Nucleus Determines Free-Running Period in the Rat. J Biol Rhythms 2022; 37:620-630. [PMID: 36181312 PMCID: PMC10001112 DOI: 10.1177/07487304221126074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Rats housed in a 22-h light-dark cycle (11:11, T22) exhibit 2 distinct circadian locomotor activity (LMA) bouts simultaneously: one is entrained to the LD cycle and a second dissociated bout maintains a period greater than 24 h. These 2 activity bouts are associated with independent clock gene oscillations in the ventrolateral (vl-) and dorsomedial (dm-) suprachiasmatic nucleus (SCN), respectively. Previous results in our laboratory have shown that the vl- and dm-SCN oscillators are weakly coupled under T22 and that the period of the dissociated bout depends on coupling between the 2 subdivisions. Here, we sought to study the behavior of the T22 SCN pacemaker upon release into free-running conditions and compare it to the behavior of the system upon release from typical 24-h (12:12, T24) entrainment. T22-desynchronized rats or T24-entrained rats were released into constant darkness (DD). Activity rhythms in T22 rats rapidly resynchronized upon release into DD, and the free-running period (FRP) of the fused rhythm was longer than the FRP of T24 rats. We then asked whether the in vivo period changes were also present in the ex vivo SCN. Per1-luc rats were desynchronized in T22 for assessment of SCN Per1-luc ex vivo. Similar to behavioral FRP, the period of ex vivo SCN explanted from T22 rats was longer than that for T24 animals. Mathematical models supported the observed behavior of the dual oscillator system as the result of mutual coupling between the vl- and dm-SCN oscillators. This bidirectionally coupled model predicted both the FRP of the T22 system and its phase-shifting response to light. Together, these data support a model of pacemaker organization in which a light-sensitive vl-SCN oscillator is mutually coupled with a light-insensitive dm-SCN oscillator, and together they determine the period of the coupled system as a whole and its response to light pulses.
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Affiliation(s)
- Michael D Schwartz
- Department of Biology and Graduate Program in Neuroscience, University of Washington, Seattle, Washington, USA
| | - Trinitat Cambras
- Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
| | - Antoni Díez-Noguera
- Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
| | - Ana Campuzano
- Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
| | - Gisele A Oda
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Shin Yamazaki
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Horacio O de la Iglesia
- Department of Biology and Graduate Program in Neuroscience, University of Washington, Seattle, Washington, USA
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Galinde AAS, Al-Mughales F, Oster H, Heyde I. Different levels of circadian (de)synchrony -- where does it hurt? F1000Res 2022; 11:1323. [PMID: 37125019 PMCID: PMC10130703 DOI: 10.12688/f1000research.127234.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
A network of cellular timers ensures the maintenance of homeostasis by temporal modulation of physiological processes across the day. These so-called circadian clocks are synchronized to geophysical time by external time cues (or zeitgebers). In modern societies, natural environmental cycles are disrupted by artificial lighting, around-the-clock availability of food or shiftwork. Such contradictory zeitgeber input promotes chronodisruption, i.e., the perturbation of internal circadian rhythms, resulting in adverse health outcomes. While this phenomenon is well described, it is still poorly understood at which level of organization perturbed rhythms impact on health and wellbeing. In this review, we discuss different levels of chronodisruption and what is known about their health effects. We summarize the results of disrupted phase coherence between external and internal time vs. misalignment of tissue clocks amongst each other, i.e., internal desynchrony. Last, phase incoherence can also occur at the tissue level itself. Here, alterations in phase coordination can emerge between cellular clocks of the same tissue or between different clock genes within the single cell. A better understanding of the mechanisms of circadian misalignment and its effects on physiology will help to find effective tools to prevent or treat disorders arising from modern-day chronodisruptive environments.
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Affiliation(s)
- Ankita AS. Galinde
- Institute of Neurobiology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, 23562, Germany
| | - Faheem Al-Mughales
- Institute of Neurobiology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, 23562, Germany
- Biochemistry Department, Faculty of Medicine and Health Sciences, Taiz University, Taiz, Yemen
| | - Henrik Oster
- Institute of Neurobiology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, 23562, Germany
| | - Isabel Heyde
- Institute of Neurobiology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, 23562, Germany
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5
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Galinde AAS, Al-Mughales F, Oster H, Heyde I. Different levels of circadian (de)synchrony -- where does it hurt? F1000Res 2022; 11:1323. [PMID: 37125019 PMCID: PMC10130703 DOI: 10.12688/f1000research.127234.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/15/2023] [Indexed: 04/05/2023] Open
Abstract
A network of cellular timers ensures the maintenance of homeostasis by temporal modulation of physiological processes across the day. These so-called circadian clocks are synchronized to geophysical time by external time cues (or zeitgebers). In modern societies, natural environmental cycles are disrupted by artificial lighting, around-the-clock availability of food or shift work. Such contradictory zeitgeber input promotes chronodisruption, i.e., the perturbation of internal circadian rhythms, resulting in adverse health outcomes. While this phenomenon is well described, it is still poorly understood at which level of organization perturbed rhythms impact on health and wellbeing. In this review, we discuss different levels of chronodisruption and what is known about their health effects. We summarize the results of disrupted phase coherence between external and internal time vs. misalignment of tissue clocks amongst each other, i.e., internal desynchrony. Last, phase incoherence can also occur at the tissue level itself. Here, alterations in phase coordination can emerge between cellular clocks of the same tissue or between different clock genes within the single cell. A better understanding of the mechanisms of circadian misalignment and its effects on physiology will help to find effective tools to prevent or treat disorders arising from modern-day chronodisruptive environments.
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Affiliation(s)
- Ankita AS. Galinde
- Institute of Neurobiology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, 23562, Germany
| | - Faheem Al-Mughales
- Institute of Neurobiology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, 23562, Germany
- Biochemistry Department, Faculty of Medicine and Health Sciences, Taiz University, Taiz, Yemen
| | - Henrik Oster
- Institute of Neurobiology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, 23562, Germany
| | - Isabel Heyde
- Institute of Neurobiology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, 23562, Germany
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6
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van Beurden AW, Schoonderwoerd RA, Tersteeg MMH, de Torres Gutiérrez P, Michel S, Blommers R, Rohling JHT, Meijer JH. Single cell model for re-entrainment to a shifted light cycle. FASEB J 2022; 36:e22518. [PMID: 36057093 PMCID: PMC9543151 DOI: 10.1096/fj.202200478r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 07/25/2022] [Accepted: 08/15/2022] [Indexed: 11/11/2022]
Abstract
Our daily 24-h rhythm is synchronized to the external light-dark cycle resulting from the Earth's daily rotation. In the mammalian brain, the suprachiasmatic nucleus (SCN) serves as the master clock and receives light-mediated input via the retinohypothalamic tract. Abrupt changes in the timing of the light-dark cycle (e.g., due to jet lag) cause a phase shift in the circadian rhythms in the SCN. Here, we investigated the effects of a 6-h delay in the light-dark cycle on PERIOD2::LUCIFERASE expression at the single-cell level in mouse SCN organotypic explants. The ensemble pattern in phase shift response obtained from individual neurons in the anterior and central SCN revealed a bimodal distribution; specifically, neurons in the ventrolateral SCN responded with a rapid phase shift, while neurons in the dorsal SCN generally did not respond to the shift in the light-dark cycle. We also stimulated the hypothalamic tract in acute SCN slices to simulate light-mediated input to the SCN; interestingly, we found similarities between the distribution and fraction of rapid shifting neurons (in response to the delay) and neurons that were excited in response to electrical stimulation. These results suggest that a subpopulation of neurons in the ventral SCN that have an excitatory response to light input, shift their clock more readily than dorsal located neurons, and initiate the SCN's entrainment to the new light-dark cycle. Thus, we propose that light-excited neurons in the anterior and central SCN play an important role in the organism's ability to adjust to changes in the external light-dark cycle.
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Affiliation(s)
- Anouk W van Beurden
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Robin A Schoonderwoerd
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Mayke M H Tersteeg
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Stephan Michel
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ruben Blommers
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jos H T Rohling
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Johanna H Meijer
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
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7
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Smith CB, van der Vinne V, McCartney E, Stowie AC, Leise TL, Martin-Burgos B, Molyneux PC, Garbutt LA, Brodsky MH, Davidson AJ, Harrington ME, Dallmann R, Weaver DR. Cell-Type-Specific Circadian Bioluminescence Rhythms in Dbp Reporter Mice. J Biol Rhythms 2022; 37:53-77. [PMID: 35023384 DOI: 10.1177/07487304211069452] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Circadian rhythms are endogenously generated physiological and molecular rhythms with a cycle length of about 24 h. Bioluminescent reporters have been exceptionally useful for studying circadian rhythms in numerous species. Here, we report development of a reporter mouse generated by modification of a widely expressed and highly rhythmic gene encoding D-site albumin promoter binding protein (Dbp). In this line of mice, firefly luciferase is expressed from the Dbp locus in a Cre recombinase-dependent manner, allowing assessment of bioluminescence rhythms in specific cellular populations. A mouse line in which luciferase expression was Cre-independent was also generated. The Dbp reporter alleles do not alter Dbp gene expression rhythms in liver or circadian locomotor activity rhythms. In vivo and ex vivo studies show the utility of the reporter alleles for monitoring rhythmicity. Our studies reveal cell-type-specific characteristics of rhythms among neuronal populations within the suprachiasmatic nuclei ex vivo. In vivo studies show Dbp-driven bioluminescence rhythms in the liver of Albumin-Cre;DbpKI/+ "liver reporter" mice. After a shift of the lighting schedule, locomotor activity achieved the proper phase relationship with the new lighting cycle more rapidly than hepatic bioluminescence did. As previously shown, restricting food access to the daytime altered the phase of hepatic rhythmicity. Our model allowed assessment of the rate of recovery from misalignment once animals were provided with food ad libitum. These studies confirm the previously demonstrated circadian misalignment following environmental perturbations and reveal the utility of this model for minimally invasive, longitudinal monitoring of rhythmicity from specific mouse tissues.
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Affiliation(s)
- Ciearra B Smith
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts.,Graduate Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, Massachusetts
| | - Vincent van der Vinne
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts.,Department of Biology, Williams College, Williamstown, Massachusetts
| | | | - Adam C Stowie
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia
| | - Tanya L Leise
- Department of Mathematics & Statistics, Amherst College, Amherst, Massachusetts
| | | | | | - Lauren A Garbutt
- Division of Biomedical Sciences, Warwick Medical School, The University of Warwick, Coventry, UK
| | - Michael H Brodsky
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, Massachusetts
| | - Alec J Davidson
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia
| | | | - Robert Dallmann
- Division of Biomedical Sciences, Warwick Medical School, The University of Warwick, Coventry, UK
| | - David R Weaver
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts.,Graduate Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, Massachusetts.,NeuroNexus Institute, University of Massachusetts Chan Medical School, Worcester, Massachusetts
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8
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Cheng AH, Fung SW, Hegazi S, Abdalla OHMH, Cheng HYM. SOX2 Regulates Neuronal Differentiation of the Suprachiasmatic Nucleus. Int J Mol Sci 2021; 23:ijms23010229. [PMID: 35008655 PMCID: PMC8745319 DOI: 10.3390/ijms23010229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/24/2022] Open
Abstract
In mammals, the hypothalamic suprachiasmatic nucleus (SCN) functions as the central circadian pacemaker, orchestrating behavioral and physiological rhythms in alignment to the environmental light/dark cycle. The neurons that comprise the SCN are anatomically and functionally heterogeneous, but despite their physiological importance, little is known about the pathways that guide their specification and differentiation. Here, we report that the stem/progenitor cell transcription factor, Sex determining region Y-box 2 (Sox2), is required in the embryonic SCN to control the expression of SCN-enriched neuropeptides and transcription factors. Ablation of Sox2 in the developing SCN leads to downregulation of circadian neuropeptides as early as embryonic day (E) 15.5, followed by a decrease in the expression of two transcription factors involved in SCN development, Lhx1 and Six6, in neonates. Thymidine analog-retention assays revealed that Sox2 deficiency contributed to reduced survival of SCN neurons during the postnatal period of cell clearance, but did not affect progenitor cell proliferation or SCN specification. Our results identify SOX2 as an essential transcription factor for the proper differentiation and survival of neurons within the developing SCN.
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Affiliation(s)
- Arthur H. Cheng
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (A.H.C.); (S.W.F.); (S.H.); (O.H.M.H.A.)
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Samuel W. Fung
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (A.H.C.); (S.W.F.); (S.H.); (O.H.M.H.A.)
| | - Sara Hegazi
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (A.H.C.); (S.W.F.); (S.H.); (O.H.M.H.A.)
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Osama Hasan Mustafa Hasan Abdalla
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (A.H.C.); (S.W.F.); (S.H.); (O.H.M.H.A.)
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Hai-Ying Mary Cheng
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (A.H.C.); (S.W.F.); (S.H.); (O.H.M.H.A.)
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
- Correspondence:
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9
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Cheng AH, Cheng HYM. Genesis of the Master Circadian Pacemaker in Mice. Front Neurosci 2021; 15:659974. [PMID: 33833665 PMCID: PMC8021851 DOI: 10.3389/fnins.2021.659974] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/04/2021] [Indexed: 12/13/2022] Open
Abstract
The suprachiasmatic nucleus (SCN) of the hypothalamus is the central circadian clock of mammals. It is responsible for communicating temporal information to peripheral oscillators via humoral and endocrine signaling, ultimately controlling overt rhythms such as sleep-wake cycles, body temperature, and locomotor activity. Given the heterogeneity and complexity of the SCN, its genesis is tightly regulated by countless intrinsic and extrinsic factors. Here, we provide a brief overview of the development of the SCN, with special emphasis on the murine system.
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Affiliation(s)
- Arthur H. Cheng
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Hai-Ying Mary Cheng
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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10
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Martin T, Bonargent T, Besnard S, Quarck G, Mauvieux B, Pigeon E, Denise P, Davenne D. Vestibular stimulation by 2G hypergravity modifies resynchronization in temperature rhythm in rats. Sci Rep 2020; 10:9216. [PMID: 32514078 PMCID: PMC7280278 DOI: 10.1038/s41598-020-65496-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 04/21/2020] [Indexed: 11/09/2022] Open
Abstract
Input from the light/dark (LD) cycle constitutes the primary synchronizing stimulus for the suprachiasmatic nucleus (SCN) circadian clock. However, the SCN can also be synchronized by non-photic inputs. Here, we hypothesized that the vestibular system, which detects head motion and orientation relative to gravity, may provide sensory inputs to synchronize circadian rhythmicity. We investigated the resynchronization of core temperature (Tc) circadian rhythm to a six-hour phase advance of the LD cycle (LD + 6) using hypergravity (2 G) as a vestibular stimulation in control and bilateral vestibular loss (BVL) rats. Three conditions were tested: an LD + 6 exposure alone, a series of seven 2 G pulses without LD + 6, and a series of seven one-hour 2 G pulses (once a day) following LD + 6. First, following LD + 6, sham rats exposed to 2 G pulses resynchronized earlier than BVL rats (p = 0.01), and earlier than sham rats exposed to LD + 6 alone (p = 0.002). Each 2 G pulse caused an acute drop of Tc in sham rats (-2.8 ± 0.3 °C; p < 0.001), while BVL rats remained unaffected. This confirms that the vestibular system influences chronobiological regulation and supports the hypothesis that vestibular input, like physical activity, should be considered as a potent time cue for biological rhythm synchronization, acting in synergy with the visual system.
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Affiliation(s)
- Tristan Martin
- UMR-S 1075 COMETE: MOBILITES "Vieillissement, Pathologies, Santé", INSERM-Normandy University, Caen, France
| | | | - Stéphane Besnard
- UMR-S 1075 COMETE: MOBILITES "Vieillissement, Pathologies, Santé", INSERM-Normandy University, Caen, France
| | - Gaëlle Quarck
- UMR-S 1075 COMETE: MOBILITES "Vieillissement, Pathologies, Santé", INSERM-Normandy University, Caen, France
| | - Benoit Mauvieux
- UMR-S 1075 COMETE: MOBILITES "Vieillissement, Pathologies, Santé", INSERM-Normandy University, Caen, France
| | - Eric Pigeon
- University, UNICAEN, ENSICAEN, LAC, 14000, Caen, France
| | - Pierre Denise
- UMR-S 1075 COMETE: MOBILITES "Vieillissement, Pathologies, Santé", INSERM-Normandy University, Caen, France
| | - Damien Davenne
- UMR-S 1075 COMETE: MOBILITES "Vieillissement, Pathologies, Santé", INSERM-Normandy University, Caen, France.
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11
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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: 40] [Impact Index Per Article: 10.0] [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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12
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Fontana JM, Tserga E, Sarlus H, Canlon B, Cederroth C. Impact of noise exposure on the circadian clock in the auditory system. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3960. [PMID: 31795664 PMCID: PMC7341678 DOI: 10.1121/1.5132290] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Circadian rhythms control the timing of all bodily functions, and misalignment in the rhythms can cause various diseases. Moreover, circadian rhythms are highly conserved and are regulated by a transcriptional-translational feedback loop of circadian genes that has a periodicity of approximately 24 h. The cochlea and the inferior colliculus (IC) have been shown to possess an autonomous and self-sustained circadian system as demonstrated by recording, in real time, the bioluminescence from PERIOD2::LUCIFERASE (PER2::LUC) mice. The cochlea and IC both express the core clock genes, Per1, Per2, Bmal1, and Rev-Erbα, where RNA abundance is rhythmically distributed with a 24 h cycle. Noise exposure alters clock gene expression in the cochlea and the IC after noise stimulation, although in different ways. These findings highlight the importance of circadian responses in the cochlea and the IC and emphasize the importance of circadian mechanisms for understanding the differences in central and peripheral auditory function and the subsequent molecular changes that occur after daytime (inactive phase) or nighttime (active phase) noise trauma.
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Affiliation(s)
- Jacopo M Fontana
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
| | - Evangelia Tserga
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
| | - Heela Sarlus
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
| | - Barbara Canlon
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
| | - Christopher Cederroth
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
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13
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Zhao J, Warman GR, Cheeseman JF. The functional changes of the circadian system organization in aging. Ageing Res Rev 2019; 52:64-71. [PMID: 31048031 DOI: 10.1016/j.arr.2019.04.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 04/14/2019] [Accepted: 04/24/2019] [Indexed: 01/12/2023]
Abstract
The circadian clock drives periodic oscillations at different levels of an organism from genes to behavior. This timing system is highly conserved across species from insects to mammals and human beings. The question of how the circadian clock is involved in the aging process continues to attract more attention. We aim to characterize the detrimental impact of aging on the circadian clock organization. We review studies on different components of the circadian clock at the central and periperal levels, and their changes in aged rodents and humans, and the fruit fly Drosophila. Intracellular signaling, cellular activity and intercellular coupling in the central pacemaker have been found to decline with advancing age. Evidence of degradation of the molecular clockwork reflected by clock gene expression in both central and peripheral oscillators due to aging is inadequate. The findings on age-associated molecular and functional changes of peripheral clocks are mixed. We conclude that aging can affect the circadian clock organization at various levels, and the impairment of the central network may be a fundamental mechanism of circadian disruption seen in aged species.
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14
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Slow shift of dead zone after an abrupt shift of the light-dark cycle. Brain Res 2019; 1714:73-80. [DOI: 10.1016/j.brainres.2019.02.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 01/24/2019] [Accepted: 02/12/2019] [Indexed: 12/27/2022]
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15
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Nicholls SK, Casiraghi LP, Wang W, Weber ET, Harrington ME. Evidence for Internal Desynchrony Caused by Circadian Clock Resetting. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2019; 92:259-270. [PMID: 31249487 PMCID: PMC6585527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Circadian disruption has been linked to markers for poor health outcomes in humans and animal models. What is it about circadian disruption that is problematic? One hypothesis is that phase resetting of the circadian system, which occurs in response to changes in environmental timing cues, leads to internal desynchrony within the organism. Internal desynchrony is understood as acute changes in phase relationships between biological rhythms from different cell groups, tissues, or organs within the body. Do we have strong evidence for internal desynchrony associated with or caused by circadian clock resetting? Here we review the literature, highlighting several key studies from measures of gene expression in laboratory rodents. We conclude that current evidence offers strong support for the premise that some protocols for light-induced resetting are associated with internal desynchrony. It is important to continue research to test whether internal desynchrony is necessary and/or sufficient for negative health impact of circadian disruption.
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Affiliation(s)
| | | | - Wanqi Wang
- Department of Genetics and Development, Columbia University Medical Center, New York, NY
| | - E. Todd Weber
- Department of Biology, Behavioral Neuroscience and Health Sciences, Rider University, Lawrenceville, NJ
| | - Mary E. Harrington
- Neuroscience Program, Smith College, Northampton, MA,To whom all correspondence should be addressed: Mary Harrington, Neuroscience Program, Clark Science Center, 44 College Lane, Smith College, Northampton, MA 01060; Tel: (413) 585-3925; Fax: (413) 585-3786;
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16
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Musashi‐2 and related stem cell proteins in the mouse suprachiasmatic nucleus and their potential role in circadian rhythms. Int J Dev Neurosci 2019; 75:44-58. [DOI: 10.1016/j.ijdevneu.2019.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 04/17/2019] [Accepted: 04/30/2019] [Indexed: 01/14/2023] Open
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17
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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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18
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Off the Clock: From Circadian Disruption to Metabolic Disease. Int J Mol Sci 2019; 20:ijms20071597. [PMID: 30935034 PMCID: PMC6480015 DOI: 10.3390/ijms20071597] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/20/2019] [Accepted: 03/27/2019] [Indexed: 12/18/2022] Open
Abstract
Circadian timekeeping allows appropriate temporal regulation of an organism’s internal metabolism to anticipate and respond to recurrent daily changes in the environment. Evidence from animal genetic models and from humans under circadian misalignment (such as shift work or jet lag) shows that disruption of circadian rhythms contributes to the development of obesity and metabolic disease. Inappropriate timing of food intake and high-fat feeding also lead to disruptions of the temporal coordination of metabolism and physiology and subsequently promote its pathogenesis. This review illustrates the impact of genetically or environmentally induced molecular clock disruption (at the level of the brain and peripheral tissues) and the interplay between the circadian system and metabolic processes. Here, we discuss some mechanisms responsible for diet-induced circadian desynchrony and consider the impact of nutritional cues in inter-organ communication, with a particular focus on the communication between peripheral organs and brain. Finally, we discuss the relay of environmental information by signal-dependent transcription factors to adjust the timing of gene oscillations. Collectively, a better knowledge of the mechanisms by which the circadian clock function can be compromised will lead to novel preventive and therapeutic strategies for obesity and other metabolic disorders arising from circadian desynchrony.
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19
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Asgari-Targhi A, Klerman EB. Mathematical modeling of circadian rhythms. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2019; 11:e1439. [PMID: 30328684 PMCID: PMC6375788 DOI: 10.1002/wsbm.1439] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 09/05/2018] [Accepted: 09/12/2018] [Indexed: 12/22/2022]
Abstract
Circadian rhythms are endogenous ~24-hr oscillations usually entrained to daily environmental cycles of light/dark. Many biological processes and physiological functions including mammalian body temperature, the cell cycle, sleep/wake cycles, neurobehavioral performance, and a wide range of diseases including metabolic, cardiovascular, and psychiatric disorders are impacted by these rhythms. Circadian clocks are present within individual cells and at tissue and organismal levels as emergent properties from the interaction of cellular oscillators. Mathematical models of circadian rhythms have been proposed to provide a better understanding of and to predict aspects of this complex physiological system. These models can be used to: (a) manipulate the system in silico with specificity that cannot be easily achieved using in vivo and in vitro experimental methods and at lower cost, (b) resolve apparently contradictory empirical results, (c) generate hypotheses, (d) design new experiments, and (e) to design interventions for altering circadian rhythms. Mathematical models differ in structure, the underlying assumptions, the number of parameters and variables, and constraints on variables. Models representing circadian rhythms at different physiologic scales and in different species are reviewed to promote understanding of these models and facilitate their use. This article is categorized under: Physiology > Mammalian Physiology in Health and Disease Models of Systems Properties and Processes > Organ, Tissue, and Physiological Models.
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20
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Vasoactive intestinal peptide controls the suprachiasmatic circadian clock network via ERK1/2 and DUSP4 signalling. Nat Commun 2019; 10:542. [PMID: 30710088 PMCID: PMC6358603 DOI: 10.1038/s41467-019-08427-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 12/21/2018] [Indexed: 01/02/2023] Open
Abstract
The suprachiasmatic nucleus (SCN) co-ordinates circadian behaviour and physiology in mammals. Its cell-autonomous circadian oscillations pivot around a well characterised transcriptional/translational feedback loop (TTFL), whilst the SCN circuit as a whole is synchronised to solar time by its retinorecipient cells that express and release vasoactive intestinal peptide (VIP). The cell-autonomous and circuit-level mechanisms whereby VIP synchronises the SCN are poorly understood. We show that SCN slices in organotypic culture demonstrate rapid and sustained circuit-level circadian responses to VIP that are mediated at a cell-autonomous level. This is accompanied by changes across a broad transcriptional network and by significant VIP-directed plasticity in the internal phasing of the cell-autonomous TTFL. Signalling via ERK1/2 and tuning by its negative regulator DUSP4 are critical elements of the VIP-directed circadian re-programming. In summary, we provide detailed mechanistic insight into VIP signal transduction in the SCN at the level of genes, cells and neural circuit. The suprachiasmatic nucleus (SCN) synchronises daily rhythms of behaviour and physiology to the light-dark cycle. Vasoactive intestinal peptide (VIP) is important for mediating SCN entrainment; however, the underlying mechanisms are incompletely understood. Here, the authors show that the effects of VIP on the SCN are mediated by ERK1/2 and DUSP4.
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21
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Power SC, Michalik MJ, Couture-Nowak S, Kent BA, Mistlberger RE. Midday meals do not impair mouse memory. Sci Rep 2018; 8:17013. [PMID: 30451946 PMCID: PMC6242856 DOI: 10.1038/s41598-018-35427-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/02/2018] [Indexed: 11/20/2022] Open
Abstract
Nocturnal mice fed in the middle of the light period exhibit food anticipatory rhythms of behavior and physiology under control of food-entrainable circadian clocks in the brain and body. This is presumed to be adaptive by aligning behavior and physiology with predictable mealtimes. This assumption is challenged by a report that daytime feeding schedules impair cognitive processes important for survival, including object memory and contextual fear conditioning assessed at two times of day. To further evaluate these effects, mice were restricted to a 6 h daily meal in the middle of the light or dark period and object memory was tested at four times of day. Object memory was not impaired by daytime feeding, and did not exhibit circadian variation in either group. To determine whether impairment might depend on methodology, experimental procedures used previously to detect impairment were followed. Daytime feeding induced food anticipatory rhythms and shifted hippocampal clock genes, but again did not impair object memory. Spontaneous alternation and contextual fear conditioning were also not impaired. Hippocampal memory function appears more robust to time of day and daytime feeding schedules than previously reported; day-fed mice can remember what they have seen, where they have been, and where it is dangerous.
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Affiliation(s)
- Sarah C Power
- Department of Psychology, Simon Fraser University, Burnaby, Canada
| | | | | | - Brianne A Kent
- Djavad Mowafaghian Centre for Brain Health, Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, Canada
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22
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Uchida H, Nakamura TJ, Takasu NN, Obana-Koshino A, Ono H, Todo T, Sakai T, Nakamura W. The central clock controls the daily rhythm of Aqp5 expression in salivary glands. J Physiol Sci 2018; 68:377-385. [PMID: 28484984 PMCID: PMC10717580 DOI: 10.1007/s12576-017-0540-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Accepted: 04/20/2017] [Indexed: 01/20/2023]
Abstract
Salivary secretion displays day-night variations that are controlled by the circadian clock. The central clock in the suprachiasmatic nucleus (SCN) regulates daily physiological rhythms by prompting peripheral oscillators to adjust to changing environments. Aquaporin 5 (Aqp5) is known to play a key role in salivary secretion, but the association between Aqp5 and the circadian rhythm is poorly understood. The aim of our study was to evaluate whether Aqp5 expression in submandibular glands (SMGs) is driven by the central clock in the SCN or by autonomous oscillations. We observed circadian oscillations in the activity of period circadian protein homolog 2 and luciferase fusion protein (PER2::LUC) in cultured SMGs with periodicity depending on core clock genes. A daily rhythm was detected in the expression profiles of Aqp5 in SMGs in vivo. In cultured SMGs ex vivo, clock genes showed distinct circadian rhythms, whereas Aqp5 expression did not. These data indicate that daily Aqp5 expression in the mouse SMG is driven by the central clock in the SCN.
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Affiliation(s)
- Hitoshi Uchida
- Department of Oral-Chrono Physiology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, Nagasaki, 852-8588, Japan
- Department of Oral-Facial Disorders, Graduate School of Dentistry, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Takahiro J Nakamura
- Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki, Kanagawa, 214-8571, Japan
- Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Tokyo, 164-8530, Japan
| | - Nana N Takasu
- Department of Oral-Chrono Physiology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, Nagasaki, 852-8588, Japan
| | - Aya Obana-Koshino
- Department of Oral-Facial Disorders, Graduate School of Dentistry, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Hitomi Ono
- Department of Oral-Facial Disorders, Graduate School of Dentistry, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Takeshi Todo
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Takayoshi Sakai
- Department of Oral-Facial Disorders, Graduate School of Dentistry, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Wataru Nakamura
- Department of Oral-Chrono Physiology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, Nagasaki, 852-8588, Japan.
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23
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Khan S, Nabi G, Yao L, Siddique R, Sajjad W, Kumar S, Duan P, Hou H. Health risks associated with genetic alterations in internal clock system by external factors. Int J Biol Sci 2018; 14:791-798. [PMID: 29910689 PMCID: PMC6001675 DOI: 10.7150/ijbs.23744] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 03/28/2018] [Indexed: 12/20/2022] Open
Abstract
The circadian system maintains the main aspects of physiological and behavioral processes. Both circadian rhythm and sleep impact an organism's health through interaction with environmental factors. Variations in external factors influence the functionality of clock genes and disrupt 24-hour rhythmic cycle. The disrupted circadian rhythm and disregulated sleep affect an organism's health, thereby causing several disorders including cancer, depression and cardiac disorders. Considering the role of clock genes and environmental factors, extensive investigation is required focusing on pathways involved in development of life-threatening disorders. This review identifies the major risks and associated factors related with disruption in circadian system and sleep.
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Affiliation(s)
- Suliman Khan
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, P.R China
- Henan Key Laboratory of Ecological Security for Water Source Region of Mid-line of South-to-North Diversion Project, Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University
- University of Chinese Academy of Sciences, Beijing 100049
| | - Ghulam Nabi
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, P.R China
- University of Chinese Academy of Sciences, Beijing 100049
| | - Lunguang Yao
- Henan Key Laboratory of Ecological Security for Water Source Region of Mid-line of South-to-North Diversion Project, Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University
| | - Rabeea Siddique
- Advanced Biomaterials and Tissue Engineering Center and Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wasim Sajjad
- University of Chinese Academy of Sciences, Beijing 100049
- Key Laboratory of Petroleum Resources, Gansu Province / Key Laboratory of Petroleum Resources Research, Institute of Geology and geophysics, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Sunjeet Kumar
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, P.R China
| | - Pengfei Duan
- Henan Key Laboratory of Ecological Security for Water Source Region of Mid-line of South-to-North Diversion Project, Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University
| | - Hongwei Hou
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, P.R China
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24
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Honma S. The mammalian circadian system: a hierarchical multi-oscillator structure for generating circadian rhythm. J Physiol Sci 2018; 68:207-219. [PMID: 29460036 PMCID: PMC10717972 DOI: 10.1007/s12576-018-0597-5] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/25/2018] [Indexed: 10/18/2022]
Abstract
The circadian nature of physiology and behavior is regulated by a circadian clock that generates intrinsic rhythms with a periodicity of approximately 24 h. The mammalian circadian system is composed of a hierarchical multi-oscillator structure, with the central clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus regulating the peripheral clocks found throughout the body. In the past two decades, key clock genes have been discovered in mammals and shown to be interlocked in transcriptional and translational feedback loops. At the cellular level, each cell is governed by its own independent clock; and yet, these cellular circadian clocks in the SCN form regional oscillators that are further coupled to one another to generate a single rhythm for the tissue. The oscillatory coupling within and between the regional oscillators appears to be critical for the extraordinary stability and the wide range of adaptability of the circadian clock, the mechanism of which is now being elucidated with newly advanced molecular tools.
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Affiliation(s)
- Sato Honma
- Research and Education Center for Brain Science, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, 060-8638, Japan.
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25
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Mendoza-Viveros L, Obrietan K, Cheng HYM. Commentary: miR-132/212 Modulates Seasonal Adaptation and Dendritic Morphology of the Central Circadian Clock. JOURNAL OF NEUROLOGY & NEUROMEDICINE 2018; 3:21-25. [PMID: 29682634 PMCID: PMC5906796 DOI: 10.29245/2572.942x/2017/1.1169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Daily rhythms in behavior and physiology are coordinated by an endogenous clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. This central pacemaker also relays day length information to allow for seasonal adaptation, a process for which melatonin signaling is essential. How the SCN encodes day length is not fully understood. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression by directing target mRNAs for degradation or translational repression. The miR-132/212 cluster plays a key role in facilitating neuronal plasticity, and miR-132 has been shown previously to modulate resetting of the central clock. A recent study from our group showed that miR-132/212 in mice is required for optimal adaptation to seasons and non-24-hour light/dark cycles through regulation of its target gene, methyl CpG-binding protein (MeCP2), in the SCN and dendritic spine density of SCN neurons. Furthermore, in the seasonal rodent Mesocricetus auratus (Syrian hamster), adaptation to short photoperiods is accompanied by structural plasticity in the SCN independently of melatonin signaling, thus further supporting a key role for SCN structural and, in turn, functional plasticity in the coding of day length. In this commentary, we discuss our recent findings in context of what is known about day length encoding by the SCN, and propose future directions.
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Affiliation(s)
- Lucia Mendoza-Viveros
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G3, Canada
| | - Karl Obrietan
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | - Hai-Ying M. Cheng
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G3, Canada
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26
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Belle MDC, Diekman CO. Neuronal oscillations on an ultra-slow timescale: daily rhythms in electrical activity and gene expression in the mammalian master circadian clockwork. Eur J Neurosci 2018; 48:2696-2717. [PMID: 29396876 DOI: 10.1111/ejn.13856] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/16/2018] [Accepted: 01/28/2018] [Indexed: 12/17/2022]
Abstract
Neuronal oscillations of the brain, such as those observed in the cortices and hippocampi of behaving animals and humans, span across wide frequency bands, from slow delta waves (0.1 Hz) to ultra-fast ripples (600 Hz). Here, we focus on ultra-slow neuronal oscillators in the hypothalamic suprachiasmatic nuclei (SCN), the master daily clock that operates on interlocking transcription-translation feedback loops to produce circadian rhythms in clock gene expression with a period of near 24 h (< 0.001 Hz). This intracellular molecular clock interacts with the cell's membrane through poorly understood mechanisms to drive the daily pattern in the electrical excitability of SCN neurons, exhibiting an up-state during the day and a down-state at night. In turn, the membrane activity feeds back to regulate the oscillatory activity of clock gene programs. In this review, we emphasise the circadian processes that drive daily electrical oscillations in SCN neurons, and highlight how mathematical modelling contributes to our increasing understanding of circadian rhythm generation, synchronisation and communication within this hypothalamic region and across other brain circuits.
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Affiliation(s)
- Mino D C Belle
- Institute of Clinical and Biomedical Sciences, University of Exeter Medical School, University of Exeter, Exeter, EX4 4PS, UK
| | - Casey O Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, NJ, USA.,Institute for Brain and Neuroscience Research, New Jersey Institute of Technology, Newark, NJ, USA
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27
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Shiftwork-Mediated Disruptions of Circadian Rhythms and Sleep Homeostasis Cause Serious Health Problems. Int J Genomics 2018; 2018:8576890. [PMID: 29607311 PMCID: PMC5828540 DOI: 10.1155/2018/8576890] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/12/2017] [Indexed: 12/12/2022] Open
Abstract
Shiftwork became common during the last few decades with the growing demands of human life. Despite the social inactivity and irregularity in habits, working in continuous irregular shifts causes serious health issues including sleep disorders, psychiatric disorders, cancer, and metabolic disorders. These health problems arise due to the disruption in circadian clock system, which is associated with alterations in genetic expressions. Alteration in clock controlling genes further affects genes linked with disorders including major depression disorder, bipolar disorder, phase delay and phase advance sleep syndromes, breast cancer, and colon cancer. A diverse research work is needed focusing on broad spectrum changes caused by jet lag in brain and neuronal system. This review is an attempt to motivate the researchers to conduct advanced studies in this area to identify the risk factors and mechanisms. Its goal is extended to make the shift workers aware about the risks associated with shiftwork.
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28
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Tackenberg MC, McMahon DG. Photoperiodic Programming of the SCN and Its Role in Photoperiodic Output. Neural Plast 2018; 2018:8217345. [PMID: 29552032 PMCID: PMC5818903 DOI: 10.1155/2018/8217345] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/22/2017] [Indexed: 11/18/2022] Open
Abstract
Though the seasonal response of organisms to changing day lengths is a phenomenon that has been scientifically reported for nearly a century, significant questions remain about how photoperiod is encoded and effected neurobiologically. In mammals, early work identified the master circadian clock, the suprachiasmatic nuclei (SCN), as a tentative encoder of photoperiodic information. Here, we provide an overview of research on the SCN as a coordinator of photoperiodic responses, the intercellular coupling changes that accompany that coordination, as well as the SCN's role in a putative brain network controlling photoperiodic input and output. Lastly, we discuss the importance of photoperiodic research in the context of tangible benefits to human health that have been realized through this research as well as challenges that remain.
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Affiliation(s)
| | - Douglas G. McMahon
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
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29
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Park JS, Cederroth CR, Basinou V, Sweetapple L, Buijink R, Lundkvist GB, Michel S, Canlon B. Differential Phase Arrangement of Cellular Clocks along the Tonotopic Axis of the Mouse Cochlea Ex Vivo. Curr Biol 2017; 27:2623-2629.e2. [PMID: 28823676 PMCID: PMC6899219 DOI: 10.1016/j.cub.2017.07.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/15/2017] [Accepted: 07/07/2017] [Indexed: 12/18/2022]
Abstract
Topological distributions of individual cellular clocks have not been demonstrated in peripheral organs. The cochlea displays circadian patterns of core clock gene expression [1, 2]. PER2 protein is expressed in the hair cells and spiral ganglion neurons of the cochlea in the spiral ganglion neurons [1]. To investigate the topological organization of cellular oscillators in the cochlea, we recorded circadian rhythms from mouse cochlear explants using highly sensitive real-time tracking of PER2::LUC bioluminescence. Here, we show cell-autonomous and self-sustained oscillations originating from hair cells and spiral ganglion neurons. Multi-phased cellular clocks were arranged along the length of the cochlea with oscillations initiating at the apex (low-frequency region) and traveling toward the base (high-frequency region). Phase differences of 3 hr were found between cellular oscillators in the apical and middle regions and from isolated individual cochlear regions, indicating that cellular networks organize the rhythms along the tonotopic axis. This is the first demonstration of a spatiotemporal arrangement of circadian clocks at the cellular level in a peripheral organ. Cochlear rhythms were disrupted in the presence of either voltage-gated potassium channel blocker (TEA) or extracellular calcium chelator (BAPTA), demonstrating that multiple types of ion channels contribute to the maintenance of coherent rhythms. In contrast, preventing action potentials with tetrodotoxin (TTX) or interfering with cell-to-cell communication the broad-spectrum gap junction blocker (CBX [carbenoxolone]) had no influence on cochlear rhythms. These findings highlight a dynamic regulation and longitudinal distribution of cellular clocks in the cochlea.
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Affiliation(s)
- Jung-Sub Park
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Otolaryngology, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon 16499, Korea
| | | | - Vasiliki Basinou
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Lara Sweetapple
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Renate Buijink
- Department of Molecular Cell Biology, Leiden University Medical Center, 2333 Leiden, the Netherlands
| | - Gabriella B Lundkvist
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden; Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Stephan Michel
- Department of Molecular Cell Biology, Leiden University Medical Center, 2333 Leiden, the Netherlands
| | - Barbara Canlon
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden.
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30
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Ubaldo-Reyes L, Buijs R, Escobar C, Ángeles-Castellanos M. Scheduled meal accelerates entrainment to a 6-h phase advance by shifting central and peripheral oscillations in rats. Eur J Neurosci 2017; 46:1875-1886. [DOI: 10.1111/ejn.13633] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 04/24/2017] [Accepted: 06/20/2017] [Indexed: 12/11/2022]
Affiliation(s)
- L.M. Ubaldo-Reyes
- Departamento de Anatomía; Facultad de Medicina; Universidad Nacional Autónoma de México; México DF 04510 Mexico
| | - R.M. Buijs
- Laboratorio Mecanismos de Integración Hipotalámica; Instituto de Investigaciones Biomédicas; Universidad Nacional Autónoma de México; México DF Mexico
| | - C. Escobar
- Departamento de Anatomía; Facultad de Medicina; Universidad Nacional Autónoma de México; México DF 04510 Mexico
| | - M. Ángeles-Castellanos
- Departamento de Anatomía; Facultad de Medicina; Universidad Nacional Autónoma de México; México DF 04510 Mexico
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31
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Mendoza-Viveros L, Chiang CK, Ong JLK, Hegazi S, Cheng AH, Bouchard-Cannon P, Fana M, Lowden C, Zhang P, Bothorel B, Michniewicz MG, Magill ST, Holmes MM, Goodman RH, Simonneaux V, Figeys D, Cheng HYM. miR-132/212 Modulates Seasonal Adaptation and Dendritic Morphology of the Central Circadian Clock. Cell Rep 2017; 19:505-520. [PMID: 28423315 PMCID: PMC5864111 DOI: 10.1016/j.celrep.2017.03.057] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 01/11/2017] [Accepted: 03/17/2017] [Indexed: 02/04/2023] Open
Abstract
The central circadian pacemaker, the suprachiasmatic nucleus (SCN), encodes day length information by mechanisms that are not well understood. Here, we report that genetic ablation of miR-132/212 alters entrainment to different day lengths and non-24 hr day-night cycles, as well as photoperiodic regulation of Period2 expression in the SCN. SCN neurons from miR-132/212-deficient mice have significantly reduced dendritic spine density, along with altered methyl CpG-binding protein (MeCP2) rhythms. In Syrian hamsters, a model seasonal rodent, day length regulates spine density on SCN neurons in a melatonin-independent manner, as well as expression of miR-132, miR-212, and their direct target, MeCP2. Genetic disruption of Mecp2 fully restores the level of dendritic spines of miR-132/212-deficient SCN neurons. Our results reveal that, by regulating the dendritic structure of SCN neurons through a MeCP2-dependent mechanism, miR-132/212 affects the capacity of the SCN to encode seasonal time.
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Affiliation(s)
- Lucia Mendoza-Viveros
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Cheng-Kang Chiang
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Jonathan L K Ong
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Sara Hegazi
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Arthur H Cheng
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Pascale Bouchard-Cannon
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Michael Fana
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Christopher Lowden
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Peng Zhang
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Béatrice Bothorel
- Institut des Neurosciences Cellulaires et Intégratives, UPR CNRS 3212, Université de Strasbourg, 5 rue Blaise Pascal, 67084 Strasbourg, France
| | - Matthew G Michniewicz
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Stephen T Magill
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Melissa M Holmes
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada; Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Richard H Goodman
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Valérie Simonneaux
- Institut des Neurosciences Cellulaires et Intégratives, UPR CNRS 3212, Université de Strasbourg, 5 rue Blaise Pascal, 67084 Strasbourg, France
| | - Daniel Figeys
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada; Canadian Institute for Advanced Research, 180 Dundas Street West, Toronto, ON M5G 1Z8, Canada
| | - Hai-Ying M Cheng
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada.
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32
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Taylor SR, Wang TJ, Granados-Fuentes D, Herzog ED. Resynchronization Dynamics Reveal that the Ventral Entrains the Dorsal Suprachiasmatic Nucleus. J Biol Rhythms 2017; 32:35-47. [PMID: 28326909 PMCID: PMC5483321 DOI: 10.1177/0748730416680904] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Although the suprachiasmatic nucleus (SCN) has long been considered the master circadian clock in mammals, the topology of the connections that synchronize daily rhythms among SCN cells is not well understood. We combined experimental and computational methods to infer the directed interactions that mediate circadian synchrony between regions of the SCN. We analyzed PERIOD2 (PER2) expression from SCN slices during and after treatment with tetrodotoxin, allowing us to map connections as cells resynchronized their daily cycling following blockade and restoration of cell-cell communication. Using automated analyses, we found that cells in the dorsal SCN stabilized their periods slower than those in the ventral SCN. A phase-amplitude computational model of the SCN revealed that, to reproduce the experimental results: (1) the ventral SCN had to be more densely connected than the dorsal SCN and (2) the ventral SCN needed strong connections to the dorsal SCN. Taken together, these results provide direct evidence that the ventral SCN entrains the dorsal SCN in constant conditions.
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Affiliation(s)
| | - Thomas J. Wang
- Department of Biology, Washington University, St. Louis, Missouri, USA
| | | | - Erik D. Herzog
- Department of Biology, Washington University, St. Louis, Missouri, USA
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33
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Liu F, Chang HC. Physiological links of circadian clock and biological clock of aging. Protein Cell 2017; 8:477-488. [PMID: 28108951 PMCID: PMC5498335 DOI: 10.1007/s13238-016-0366-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 12/20/2016] [Indexed: 12/20/2022] Open
Abstract
Circadian rhythms orchestrate biochemical and physiological processes in living organisms to respond the day/night cycle. In mammals, nearly all cells hold self-sustained circadian clocks meanwhile couple the intrinsic rhythms to systemic changes in a hierarchical manner. The suprachiasmatic nucleus (SCN) of the hypothalamus functions as the master pacemaker to initiate daily synchronization according to the photoperiod, in turn determines the phase of peripheral cellular clocks through a variety of signaling relays, including endocrine rhythms and metabolic cycles. With aging, circadian desynchrony occurs at the expense of peripheral metabolic pathologies and central neurodegenerative disorders with sleep symptoms, and genetic ablation of circadian genes in model organisms resembled the aging-related features. Notably, a number of studies have linked longevity nutrient sensing pathways in modulating circadian clocks. Therapeutic strategies that bridge the nutrient sensing pathways and circadian clock might be rational designs to defy aging.
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Affiliation(s)
- Fang Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China.,University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Hung-Chun Chang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China.
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34
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Azzi A, Evans JA, Leise T, Myung J, Takumi T, Davidson AJ, Brown SA. Network Dynamics Mediate Circadian Clock Plasticity. Neuron 2017; 93:441-450. [PMID: 28065650 DOI: 10.1016/j.neuron.2016.12.022] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 09/01/2016] [Accepted: 12/09/2016] [Indexed: 11/19/2022]
Abstract
A circadian clock governs most aspects of mammalian behavior. Although its properties are in part genetically determined, altered light-dark environment can change circadian period length through a mechanism requiring de novo DNA methylation. We show here that this mechanism is mediated not via cell-autonomous clock properties, but rather through altered networking within the suprachiasmatic nuclei (SCN), the circadian "master clock," which is DNA methylated in region-specific manner. DNA methylation is necessary to temporally reorganize circadian phasing among SCN neurons, which in turn changes the period length of the network as a whole. Interruption of neural communication by inhibiting neuronal firing or by physical cutting suppresses both SCN reorganization and period changes. Mathematical modeling suggests, and experiments confirm, that this SCN reorganization depends upon GABAergic signaling. Our results therefore show that basic circadian clock properties are governed by dynamic interactions among SCN neurons, with neuroadaptations in network function driven by the environment.
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Affiliation(s)
- Abdelhalim Azzi
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Jennifer A Evans
- Department of Biomedical Sciences, College of Health Sciences, Marquette University, 1250 W. Wisconsin Ave., Milwaukee, WI 53233, USA
| | - Tanya Leise
- Department of Mathematics and Statistics, Amherst College, 220 S. Pleasant St., Amherst, MA 01002, USA
| | - Jihwan Myung
- RIKEN Brain Science Institute (BSI), 2-1 Hirosawa Wako City, Saitama 351-0198, Japan
| | - Toru Takumi
- RIKEN Brain Science Institute (BSI), 2-1 Hirosawa Wako City, Saitama 351-0198, Japan
| | - Alec J Davidson
- Department of Neurobiology, Morehouse School of Medicine, 720 Westview Dr., Atlanta, GA 30310, USA
| | - Steven A Brown
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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35
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van Ee R, Van de Cruys S, Schlangen LJ, Vlaskamp BN. Circadian-Time Sickness: Time-of-Day Cue-Conflicts Directly Affect Health. Trends Neurosci 2016; 39:738-749. [DOI: 10.1016/j.tins.2016.09.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/06/2016] [Accepted: 09/13/2016] [Indexed: 10/20/2022]
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36
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Rozov SV, Zant JC, Gurevicius K, Porkka-Heiskanen T, Panula P. Altered Electroencephalographic Activity Associated with Changes in the Sleep-Wakefulness Cycle of C57BL/6J Mice in Response to a Photoperiod Shortening. Front Behav Neurosci 2016; 10:168. [PMID: 27630549 PMCID: PMC5005378 DOI: 10.3389/fnbeh.2016.00168] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/17/2016] [Indexed: 11/13/2022] Open
Abstract
AIM Under natural conditions diurnal rhythms of biological processes of the organism are synchronized with each other and to the environmental changes by means of the circadian system. Disturbances of the latter affect hormonal levels, sleep-wakefulness cycle and cognitive performance. To study mechanisms of such perturbations animal models subjected to artificial photoperiods are often used. The goal of current study was to understand the effects of circadian rhythm disruption, caused by a short light-dark cycle regime, on activity of the cerebral cortex in rodents. METHODS We used electroencephalogram to assess the distribution of vigilance states, perform spectral analysis, and estimate the homeostatic sleep drive. In addition, we analyzed spontaneous locomotion of C57BL/6J mice under symmetric, 22-, 21-, and 20-h-long light-dark cycles using video recording and tracking methods. RESULTS AND CONCLUSIONS We found that shortening of photoperiod caused a significant increase of slow wave activity during non-rapid eye movement sleep suggesting an elevation of sleep pressure under such conditions. While the rhythm of spontaneous locomotion was completely entrained by all light-dark cycles tested, periodic changes in the power of the θ- and γ-frequency ranges during wakefulness gradually disappeared under 22- and 21-h-long light-dark cycles. This was associated with a significant increase in the θ-γ phase-amplitude coupling during wakefulness. Our results thus provide deeper understanding of the mechanisms underlying the impairment of learning and memory retention, which is associated with disturbed circadian regulation.
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Affiliation(s)
- Stanislav V Rozov
- Department of Anatomy, Faculty of Medicine, Neuroscience Center, University of Helsinki Helsinki, Finland
| | - Janneke C Zant
- Department of Physiology, Faculty of Medicine, University of Helsinki Helsinki, Finland
| | - Kestutis Gurevicius
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | | | - Pertti Panula
- Department of Anatomy, Faculty of Medicine, Neuroscience Center, University of Helsinki Helsinki, Finland
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37
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Evans JA. Collective timekeeping among cells of the master circadian clock. J Endocrinol 2016; 230:R27-49. [PMID: 27154335 PMCID: PMC4938744 DOI: 10.1530/joe-16-0054] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/06/2016] [Indexed: 01/09/2023]
Abstract
The suprachiasmatic nucleus (SCN) of the anterior hypothalamus is the master circadian clock that coordinates daily rhythms in behavior and physiology in mammals. Like other hypothalamic nuclei, the SCN displays an impressive array of distinct cell types characterized by differences in neurotransmitter and neuropeptide expression. Individual SCN neurons and glia are able to display self-sustained circadian rhythms in cellular function that are regulated at the molecular level by a 24h transcriptional-translational feedback loop. Remarkably, SCN cells are able to harmonize with one another to sustain coherent rhythms at the tissue level. Mechanisms of cellular communication in the SCN network are not completely understood, but recent progress has provided insight into the functional roles of several SCN signaling factors. This review discusses SCN organization, how intercellular communication is critical for maintaining network function, and the signaling mechanisms that play a role in this process. Despite recent progress, our understanding of SCN circuitry and coupling is far from complete. Further work is needed to map SCN circuitry fully and define the signaling mechanisms that allow for collective timekeeping in the SCN network.
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Affiliation(s)
- Jennifer A Evans
- Department of Biomedical SciencesMarquette University, Milwaukee, WI, USA
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38
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Abstract
Breast cancer is already the most common malignancy affecting women worldwide, and evidence is mounting that breast cancer induced by circadian disruption (CD) is a warranted concern. Numerous studies have investigated various aspects of the circadian clock in relation to breast cancer, and evidence from these studies indicates that melatonin and the core clock genes can play a crucial role in breast cancer development. Even though epigenetics has been increasingly recognized as a key player in the etiology of breast cancer and linked to circadian rhythms, and there is evidence of overlap between epigenetic deregulation and breast cancer induced by circadian disruption, only a handful of studies have directly investigated the role of epigenetics in CD-induced breast cancer. This review explores the circadian clock and breast cancer, and the growing role of epigenetics in breast cancer development and circadian rhythms. We also summarize the current knowledge and next steps for the investigation of the epigenetic link in CD-induced breast cancer.
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Affiliation(s)
- David Z Kochan
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
| | - Olga Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
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39
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Evans JA, Gorman MR. In synch but not in step: Circadian clock circuits regulating plasticity in daily rhythms. Neuroscience 2016; 320:259-80. [PMID: 26861419 DOI: 10.1016/j.neuroscience.2016.01.072] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 01/26/2016] [Accepted: 01/27/2016] [Indexed: 11/16/2022]
Abstract
The suprachiasmatic nucleus (SCN) is a network of neural oscillators that program daily rhythms in mammalian behavior and physiology. Over the last decade much has been learned about how SCN clock neurons coordinate together in time and space to form a cohesive population. Despite this insight, much remains unknown about how SCN neurons communicate with one another to produce emergent properties of the network. Here we review the current understanding of communication among SCN clock cells and highlight a collection of formal assays where changes in SCN interactions provide for plasticity in the waveform of circadian rhythms in behavior. Future studies that pair analytical behavioral assays with modern neuroscience techniques have the potential to provide deeper insight into SCN circuit mechanisms.
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Affiliation(s)
- J A Evans
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA.
| | - M R Gorman
- Department of Psychology, University of San Diego, La Jolla, CA, USA
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40
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41
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Cryptochrome-dependent circadian periods in the arcuate nucleus. Neurosci Lett 2015; 610:123-8. [PMID: 26542738 DOI: 10.1016/j.neulet.2015.10.071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/19/2015] [Accepted: 10/28/2015] [Indexed: 11/21/2022]
Abstract
The circadian pacemaker in the suprachiasmatic nucleus (SCN) of the hypothalamus is responsible for controlling behavioral activity rhythms, such as a free running rhythm in constant darkness. Rodents have several circadian oscillators in other brain regions including the arcuate nucleus (ARC). In specific conditions such as food anticipatory activity rhythms in the context of timed restricted feeding, an alternative circadian pace-making system has been assumed by means of circadian oscillators like the SCN. Despite extensive lesion studies, the anatomic locations of extra-SCN circadian pacemakers responsible for regulating behavioral rhythms have not been found. In the present study, we investigated circadian rhythms in the SCN and extra-SCN region of the arcuate nucleus (ARC) by analyzing PER2::LUCIFERASE expression in specific regions from wild-type C57BL/6, Cry1(-/-), and Cry2(-/-) mice. Compared to wild-type animals, we observed period shortening in both the SCN and ARC of Cry1(-/-) mice and period lengthening in Cry2(-/-) mice. Interestingly, the periods in the ARC of both genotypes were identical to those in the SCN. Moreover, the amplitudes of PER2::LUC rhythms in the ARC of all animals were decreased compared to those in the SCN. These data suggest that the ARC is a candidate circadian pacemaker outside the SCN.
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42
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Evans JA, Suen TC, Callif BL, Mitchell AS, Castanon-Cervantes O, Baker KM, Kloehn I, Baba K, Teubner BJW, Ehlen JC, Paul KN, Bartness TJ, Tosini G, Leise T, Davidson AJ. Shell neurons of the master circadian clock coordinate the phase of tissue clocks throughout the brain and body. BMC Biol 2015; 13:43. [PMID: 26099272 PMCID: PMC4489020 DOI: 10.1186/s12915-015-0157-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 06/16/2015] [Indexed: 11/18/2022] Open
Abstract
Background Daily rhythms in mammals are programmed by a master clock in the suprachiasmatic nucleus (SCN). The SCN contains two main compartments (shell and core), but the role of each region in system-level coordination remains ill defined. Herein, we use a functional assay to investigate how downstream tissues interpret region-specific outputs by using in vivo exposure to long day photoperiods to temporally dissociate the SCN. We then analyze resulting changes in the rhythms of clocks located throughout the brain and body to examine whether they maintain phase synchrony with the SCN shell or core. Results Nearly all of the 17 tissues examined in the brain and body maintain phase synchrony with the SCN shell, but not the SCN core, which indicates that downstream oscillators are set by cues controlled specifically by the SCN shell. Interestingly, we also found that SCN dissociation diminished the amplitude of rhythms in core clock gene and protein expression in brain tissues by 50–75 %, which suggests that light-driven changes in the functional organization of the SCN markedly influence the strength of rhythms in downstream tissues. Conclusions Overall, our results reveal that body clocks receive time-of-day cues specifically from the SCN shell, which may be an adaptive design principle that serves to maintain system-level phase relationships in a changing environment. Further, we demonstrate that lighting conditions alter the amplitude of the molecular clock in downstream tissues, which uncovers a new form of plasticity that may contribute to seasonal changes in physiology and behavior. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0157-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jennifer A Evans
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53233, USA.
| | - Ting-Chung Suen
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Ben L Callif
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53233, USA
| | - Andrew S Mitchell
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | | | - Kimberly M Baker
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53233, USA
| | - Ian Kloehn
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53233, USA
| | - Kenkichi Baba
- Department of Pharmacology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Brett J W Teubner
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA, 30302, USA.,Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - J Christopher Ehlen
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Ketema N Paul
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Timothy J Bartness
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA, 30302, USA
| | - Gianluca Tosini
- Department of Pharmacology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Tanya Leise
- Department of Mathematics and Statistics, Amherst College, Amherst, MA, 01002, USA
| | - Alec J Davidson
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
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43
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Ramkisoensing A, Meijer JH. Synchronization of Biological Clock Neurons by Light and Peripheral Feedback Systems Promotes Circadian Rhythms and Health. Front Neurol 2015; 6:128. [PMID: 26097465 PMCID: PMC4456861 DOI: 10.3389/fneur.2015.00128] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 05/19/2015] [Indexed: 12/16/2022] Open
Abstract
In mammals, the suprachiasmatic nucleus (SCN) functions as a circadian clock that drives 24-h rhythms in both physiology and behavior. The SCN is a multicellular oscillator in which individual neurons function as cell-autonomous oscillators. The production of a coherent output rhythm is dependent upon mutual synchronization among single cells and requires both synaptic communication and gap junctions. Changes in phase-synchronization between individual cells have consequences on the amplitude of the SCN’s electrical activity rhythm, and these changes play a major role in the ability to adapt to seasonal changes. Both aging and sleep deprivation negatively affect the circadian amplitude of the SCN, whereas behavioral activity (i.e., exercise) has a positive effect on amplitude. Given that the amplitude of the SCN’s electrical activity rhythm is essential for achieving robust rhythmicity in physiology and behavior, the mechanisms that underlie neuronal synchronization warrant further study. A growing body of evidence suggests that the functional integrity of the SCN contributes to health, well-being, cognitive performance, and alertness; in contrast, deterioration of the 24-h rhythm is a risk factor for neurodegenerative disease, cancer, depression, and sleep disorders.
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Affiliation(s)
- Ashna Ramkisoensing
- Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center , Leiden , Netherlands
| | - Johanna H Meijer
- Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center , Leiden , Netherlands
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44
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Vosko A, van Diepen HC, Kuljis D, Chiu AM, Heyer D, Terra H, Carpenter E, Michel S, Meijer JH, Colwell CS. Role of vasoactive intestinal peptide in the light input to the circadian system. Eur J Neurosci 2015; 42:1839-48. [PMID: 25885685 DOI: 10.1111/ejn.12919] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 04/11/2015] [Accepted: 04/13/2015] [Indexed: 12/11/2022]
Abstract
The neuropeptide vasoactive intestinal peptide (VIP) is expressed at high levels in a subset of neurons in the ventral region of the suprachiasmatic nucleus (SCN). While VIP is known to be important for the synchronization of the SCN network, the role of VIP in photic regulation of the circadian system has received less attention. In the present study, we found that the light-evoked increase in electrical activity in vivo was unaltered by the loss of VIP. In the absence of VIP, the ventral SCN still exhibited N-methyl-d-aspartate-evoked responses in a brain slice preparation, although the absolute levels of neural activity before and after treatment were significantly reduced. Next, we used calcium imaging techniques to determine if the loss of VIP altered the calcium influx due to retinohypothalamic tract stimulation. The magnitude of the evoked calcium influx was not reduced in the ventral SCN, but did decline in the dorsal SCN regions. We examined the time course of the photic induction of Period1 in the SCN using in situ hybridization in VIP-mutant mice. We found that the initial induction of Period1 was not reduced by the loss of this signaling peptide. However, the sustained increase in Period1 expression (after 30 min) was significantly reduced. Similar results were found by measuring the light induction of cFOS in the SCN. These findings suggest that VIP is critical for longer-term changes within the SCN circuit, but does not play a role in the acute light response.
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Affiliation(s)
- Andrew Vosko
- Department of Structural Medicine, Rocky Vista University, Parker, CO, USA
| | - Hester C van Diepen
- Laboratory of Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Dika Kuljis
- Department of Psychiatry & Biobehavioral Sciences, University of California - Los Angeles, Los Angeles, CA, 90024, USA
| | - Andrew M Chiu
- Medical Scientist Training Program, Northwestern University, Evanston, IL, USA
| | - Djai Heyer
- Laboratory of Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Huub Terra
- Laboratory of Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Ellen Carpenter
- Department of Psychiatry & Biobehavioral Sciences, University of California - Los Angeles, Los Angeles, CA, 90024, USA
| | - Stephan Michel
- Laboratory of Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Johanna H Meijer
- Laboratory of Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Christopher S Colwell
- Department of Psychiatry & Biobehavioral Sciences, University of California - Los Angeles, Los Angeles, CA, 90024, USA
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45
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Meijer JH, Michel S. Neurophysiological Analysis of the Suprachiasmatic Nucleus. Methods Enzymol 2015; 552:75-102. [DOI: 10.1016/bs.mie.2014.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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46
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Elvira AL, Caldelas I, De Ita-Pérez D, Díaz-Muñoz M. The circadian timing system: a recent addition in the physiological mechanisms underlying pathological and aging processes. Aging Dis 2014; 5:406-18. [PMID: 25489492 DOI: 10.14336/ad.2014.0500406] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Revised: 12/09/2013] [Accepted: 01/05/2014] [Indexed: 11/01/2022] Open
Abstract
Experimental findings and clinical observations have strengthened the association between physio-pathologic aspects of several diseases, as well as aging process, with the occurrence and control of circadian rhythms. The circadian system is composed by a principal pacemaker in the suprachiasmatic nucleus (SNC) which is in coordination with a number of peripheral circadian oscillators. Many pathological entities such as metabolic syndrome, cancer and cardiovascular events are strongly connected with a disruptive condition of the circadian cycle. Inadequate circadian physiology can be elicited by genetic defects (mutations in clock genes or circadian control genes) or physiological deficiencies (desynchronization between SCN and peripheral oscillators). In this review, we focus on the most recent experimental findings regarding molecular defects in the molecular circadian clock and the altered coordination in the circadian system that are related with clinical conditions such as metabolic diseases, cancer predisposition and physiological deficiencies associated to jet-lag and shiftwork schedules. Implications in the aging process will be also reviewed.
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Affiliation(s)
| | - Ivette Caldelas
- Instituto de Investigaciones Biomédicas, UNAM, Ciudad de México 04510, D.F., MÉXICO
| | - Dalia De Ita-Pérez
- Instituto de Investigaciones Biomédicas, UNAM, Ciudad de México 04510, D.F., MÉXICO
| | - Mauricio Díaz-Muñoz
- Instituto de Investigaciones Biomédicas, UNAM, Ciudad de México 04510, D.F., MÉXICO
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47
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Leise TL, Harrington ME, Molyneux PC, Song I, Queenan H, Zimmerman E, Lall GS, Biello SM. Voluntary exercise can strengthen the circadian system in aged mice. AGE (DORDRECHT, NETHERLANDS) 2013; 35:2137-2152. [PMID: 23340916 PMCID: PMC3825002 DOI: 10.1007/s11357-012-9502-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 12/05/2012] [Indexed: 06/01/2023]
Abstract
Consistent daily rhythms are important to healthy aging according to studies linking disrupted circadian rhythms with negative health impacts. We studied the effects of age and exercise on baseline circadian rhythms and on the circadian system's ability to respond to the perturbation induced by an 8 h advance of the light:dark (LD) cycle as a test of the system's robustness. Mice (male, mPer2(luc)/C57BL/6) were studied at one of two ages: 3.5 months (n = 39) and >18 months (n = 72). We examined activity records of these mice under entrained and shifted conditions as well as mPER2::LUC measures ex vivo to assess circadian function in the suprachiasmatic nuclei (SCN) and important target organs. Age was associated with reduced running wheel use, fragmentation of activity, and slowed resetting in both behavioral and molecular measures. Furthermore, we observed that for aged mice, the presence of a running wheel altered the amplitude of the spontaneous firing rate rhythm in the SCN in vitro. Following a shift of the LD cycle, both young and aged mice showed a change in rhythmicity properties of the mPER2::LUC oscillation of the SCN in vitro, and aged mice exhibited longer lasting internal desynchrony. Access to a running wheel alleviated some age-related changes in the circadian system. In an additional experiment, we replicated the effect of the running wheel, comparing behavioral and in vitro results from aged mice housed with or without a running wheel (>21 months, n = 8 per group, all examined 4 days after the shift). The impact of voluntary exercise on circadian rhythm properties in an aged animal is a novel finding and has implications for the health of older people living with environmentally induced circadian disruption.
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Affiliation(s)
- T. L. Leise
- Mathematics Department, Amherst College, Amherst, MA 01002 USA
| | | | - P. C. Molyneux
- Neuroscience Program, Smith College, Northampton, MA 01063 USA
| | - I. Song
- Neuroscience Program, Smith College, Northampton, MA 01063 USA
| | - H. Queenan
- Neuroscience Program, Smith College, Northampton, MA 01063 USA
| | - E. Zimmerman
- Neuroscience Program, Smith College, Northampton, MA 01063 USA
| | - G. S. Lall
- Medway School of Pharmacy, University of Kent, Central Avenue, Chatham, Kent, ME4 4TB UK
| | - S. M. Biello
- School of Psychology, University of Glasgow, Glasgow, G12 8QB Scotland UK
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48
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Cao R, Robinson B, Xu H, Gkogkas C, Khoutorsky A, Alain T, Yanagiya A, Nevarko T, Liu AC, Amir S, Sonenberg N. Translational control of entrainment and synchrony of the suprachiasmatic circadian clock by mTOR/4E-BP1 signaling. Neuron 2013; 79:712-24. [PMID: 23972597 DOI: 10.1016/j.neuron.2013.06.026] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2013] [Indexed: 11/28/2022]
Abstract
Protein synthesis is critical for circadian clock function, but little is known of how translational regulation controls the master pacemaker in mammals, the suprachiasmatic nucleus (SCN). Here we demonstrate that the pivotal translational repressor, the eukaryotic translational initiation factor 4E binding protein 1 (4E-BP1), is rhythmically regulated via the mechanistic target of rapamycin (mTOR) signaling in the SCN and preferentially represses vasoactive intestinal peptide (Vip) mRNA translation. Knockout (KO) of Eif4ebp1 (gene encoding 4E-BP1) leads to upregulation of VIP and higher amplitude of molecular rhythms in the SCN. Consequently, the 4E-BP1 null mice exhibit accelerated re-entrainment to a shifted light/dark cycle and are more resistant to the rhythm-disruptive effects of constant light. Conversely, in Mtor(+/-) mice VIP expression is decreased and susceptibility to the effects of constant light is increased. These results reveal a key role for mTOR/4E-BP1-mediated translational control in regulating entrainment and synchrony of the master clock.
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Affiliation(s)
- Ruifeng Cao
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montreal, QC H3A 1A3, Canada
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Koinuma S, Asakawa T, Nagano M, Furukawa K, Sujino M, Masumoto KH, Nakajima Y, Hashimoto S, Yagita K, Shigeyoshi Y. Regional circadian period difference in the suprachiasmatic nucleus of the mammalian circadian center. Eur J Neurosci 2013; 38:2832-41. [PMID: 23869693 DOI: 10.1111/ejn.12308] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 06/12/2013] [Indexed: 01/15/2023]
Abstract
The suprachiasmatic nucleus (SCN) is the mammalian circadian rhythm center. Individual oscillating neurons have different endogenous circadian periods, but they are usually synchronized by an intercellular coupling mechanism. The differences in the period of each oscillating neuron have been extensively studied; however, the clustering of oscillators with similar periods has not been reported. In the present study, we artificially disrupted the intercellular coupling among oscillating neurons in the SCN and observed regional differences in the periods of the oscillating small-latticed regions of the SCN using a transgenic rat carrying a luciferase reporter gene driven by regulatory elements from a per2 clock gene (Per2::dluc rat). The analysis divided the SCN into two regions--aregion with periods shorter than 24 h (short-period region, SPR) and another with periods longer than 24 h (long-period region, LPR). The SPR was located in the smaller medial region of the dorsal SCN, whereas the LPR occupied the remaining larger region. We also found that slices containing the medial region of the SCN generated shorter circadian periods than slices that contained the lateral region of the SCN. Interestingly, the SPR corresponded well with the region where the SCN phase wave is generated. We numerically simulated the relationship between the SPR and a large LPR. A mathematical model of the SCN based on our findings faithfully reproduced the kinetics of the oscillators in the SCN in synchronized conditions, assuming the existence of clustered short-period oscillators.
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Affiliation(s)
- Satoshi Koinuma
- Department of Anatomy and Neurobiology, Faculty of Medicine, Kinki University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
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50
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Golombek DA, Casiraghi LP, Agostino PV, Paladino N, Duhart JM, Plano SA, Chiesa JJ. The times they're a-changing: effects of circadian desynchronization on physiology and disease. ACTA ACUST UNITED AC 2013; 107:310-22. [PMID: 23545147 DOI: 10.1016/j.jphysparis.2013.03.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Circadian rhythms are endogenous and need to be continuously entrained (synchronized) with the environment. Entrainment includes both coupling internal oscillators to external periodic changes as well as synchrony between the central clock and peripheral oscillators, which have been shown to exhibit different phases and resynchronization speed. Temporal desynchronization induces diverse physiological alterations that ultimately decrease quality of life and induces pathological situations. Indeed, there is a considerable amount of evidence regarding the deleterious effect of circadian dysfunction on overall health or on disease onset and progression, both in human studies and in animal models. In this review we discuss the general features of circadian entrainment and introduce diverse experimental models of desynchronization. In addition, we focus on metabolic, immune and cognitive alterations under situations of acute or chronic circadian desynchronization, as exemplified by jet-lag and shiftwork schedules. Moreover, such situations might lead to an enhanced susceptibility to diverse cancer types. Possible interventions (including light exposure, scheduled timing for meals and use of chronobiotics) are also discussed.
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Affiliation(s)
- Diego A Golombek
- Laboratory of Chronobiology, National University of Quilmes/CONICET, Buenos Aires, Argentina.
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