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Stengl M, Schneider AC. Contribution of membrane-associated oscillators to biological timing at different timescales. Front Physiol 2024; 14:1243455. [PMID: 38264332 PMCID: PMC10803594 DOI: 10.3389/fphys.2023.1243455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 12/12/2023] [Indexed: 01/25/2024] Open
Abstract
Environmental rhythms such as the daily light-dark cycle selected for endogenous clocks. These clocks predict regular environmental changes and provide the basis for well-timed adaptive homeostasis in physiology and behavior of organisms. Endogenous clocks are oscillators that are based on positive feedforward and negative feedback loops. They generate stable rhythms even under constant conditions. Since even weak interactions between oscillators allow for autonomous synchronization, coupling/synchronization of oscillators provides the basis of self-organized physiological timing. Amongst the most thoroughly researched clocks are the endogenous circadian clock neurons in mammals and insects. They comprise nuclear clockworks of transcriptional/translational feedback loops (TTFL) that generate ∼24 h rhythms in clock gene expression entrained to the environmental day-night cycle. It is generally assumed that this TTFL clockwork drives all circadian oscillations within and between clock cells, being the basis of any circadian rhythm in physiology and behavior of organisms. Instead of the current gene-based hierarchical clock model we provide here a systems view of timing. We suggest that a coupled system of autonomous TTFL and posttranslational feedback loop (PTFL) oscillators/clocks that run at multiple timescales governs adaptive, dynamic homeostasis of physiology and behavior. We focus on mammalian and insect neurons as endogenous oscillators at multiple timescales. We suggest that neuronal plasma membrane-associated signalosomes constitute specific autonomous PTFL clocks that generate localized but interlinked oscillations of membrane potential and intracellular messengers with specific endogenous frequencies. In each clock neuron multiscale interactions of TTFL and PTFL oscillators/clocks form a temporally structured oscillatory network with a common complex frequency-band comprising superimposed multiscale oscillations. Coupling between oscillator/clock neurons provides the next level of complexity of an oscillatory network. This systemic dynamic network of molecular and cellular oscillators/clocks is suggested to form the basis of any physiological homeostasis that cycles through dynamic homeostatic setpoints with a characteristic frequency-band as hallmark. We propose that mechanisms of homeostatic plasticity maintain the stability of these dynamic setpoints, whereas Hebbian plasticity enables switching between setpoints via coupling factors, like biogenic amines and/or neuropeptides. They reprogram the network to a new common frequency, a new dynamic setpoint. Our novel hypothesis is up for experimental challenge.
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Affiliation(s)
- Monika Stengl
- Department of Biology, Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
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2
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van Beurden AW, Tersteeg MMH, Michel S, van Veldhoven JPD, IJzerman AP, Rohling JHT, Meijer JH. Small-molecule CEM3 strengthens single-cell oscillators in the suprachiasmatic nucleus. FASEB J 2024; 38:e23348. [PMID: 38084798 DOI: 10.1096/fj.202300597rr] [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: 03/28/2023] [Revised: 10/25/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023]
Abstract
A robust endogenous clock is required for proper function of many physiological processes. The suprachiasmatic nucleus (SCN) constitutes our central circadian clock and allows us to adapt to daily changes in the environment. Aging can cause a decline in the amplitude of circadian rhythms in SCN and peripheral clocks, which contributes to increased risk of several chronic diseases. Strengthening clock function would therefore be an effective strategy to improve health. A high-throughput chemical screening has identified clock-enhancing molecule 3 (CEM3) as small molecule that increases circadian rhythm amplitude in cell lines and SCN explants. It is, however, currently not known whether CEM3 acts by enhancing the amplitude of individual single-cell oscillators or by enhancing synchrony among neurons. In view of CEM3's potential, it is of evident importance to clarify the mode of action of CEM3. Here, we investigated the effects of CEM3 on single-cell PERIOD2::LUCIFERASE rhythms in mouse SCN explants. CEM3 increased the amplitude in approximately 80%-90% of the individual cells in the SCN without disrupting the phase and/or period of their rhythms. Noticeably, CEM3's effect on amplitude is independent of the cell's initial amplitude. These findings make CEM3 a potential therapeutic candidate to restore compromised amplitude in circadian rhythms and will boost the development of other molecular approaches to improve health.
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Affiliation(s)
- Anouk W van Beurden
- 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
| | - Jaco P D van Veldhoven
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Adriaan P IJzerman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, 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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3
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Hermanstyne TO, Yang ND, Granados-Fuentes D, Li X, Mellor RL, Jegla T, Herzog ED, Nerbonne JM. Kv12-encoded K+ channels drive the day-night switch in the repetitive firing rates of SCN neurons. J Gen Physiol 2023; 155:e202213310. [PMID: 37516908 PMCID: PMC10373311 DOI: 10.1085/jgp.202213310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 05/11/2023] [Accepted: 07/06/2023] [Indexed: 07/31/2023] Open
Abstract
Considerable evidence suggests that day-night rhythms in the functional expression of subthreshold potassium (K+) channels regulate daily oscillations in the spontaneous firing rates of neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in mammals. The K+ conductance(s) driving these daily rhythms in the repetitive firing rates of SCN neurons, however, have not been identified. To test the hypothesis that subthreshold Kv12.1/Kv12.2-encoded K+ channels play a role, we obtained current-clamp recordings from SCN neurons in slices prepared from adult mice harboring targeted disruptions in the Kcnh8 (Kv12.1-/-) or Kcnh3 (Kv12.2-/-) locus. We found that mean nighttime repetitive firing rates were higher in Kv12.1-/- and Kv12.2-/- than in wild type (WT), SCN neurons. In marked contrast, mean daytime repetitive firing rates were similar in Kv12.1-/-, Kv12.2-/-, and WT SCN neurons, and the day-night difference in mean repetitive firing rates, a hallmark feature of WT SCN neurons, was eliminated in Kv12.1-/- and Kv12.2-/- SCN neurons. Similar results were obtained with in vivo shRNA-mediated acute knockdown of Kv12.1 or Kv12.2 in adult SCN neurons. Voltage-clamp experiments revealed that Kv12-encoded current densities in WT SCN neurons are higher at night than during the day. In addition, the pharmacological block of Kv12-encoded currents increased the mean repetitive firing rate of nighttime, but not daytime, in WT SCN neurons. Dynamic clamp-mediated subtraction of modeled Kv12-encoded currents also selectively increased the mean repetitive firing rates of nighttime WT SCN neurons. Despite the elimination of the nighttime decrease in the mean repetitive firing rates of SCN neurons, however, locomotor (wheel-running) activity remained rhythmic in Kv12.1-/-, Kv12.2-/-, and Kv12.1-targeted shRNA-expressing, and Kv12.2-targeted shRNA-expressing animals.
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Affiliation(s)
- Tracey O. Hermanstyne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Nien-Du Yang
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | | | - Xiaofan Li
- Department of Biology, The Pennsylvania State University, University Park, State College, PA, USA
| | - Rebecca L. Mellor
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Timothy Jegla
- Department of Biology, The Pennsylvania State University, University Park, State College, PA, USA
| | - Erik D. Herzog
- Department of Biology, Washington University, St. Louis, MO, USA
| | - Jeanne M. Nerbonne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
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4
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Hermanstyne TO, Yang ND, Granados-Fuentes D, Li X, Mellor RL, Jegla T, Herzog ED, Nerbonne JM. Kv12-Encoded K + Channels Drive the Day-Night Switch in the Repetitive Firing Rates of SCN Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526323. [PMID: 36778242 PMCID: PMC9915524 DOI: 10.1101/2023.01.30.526323] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Considerable evidence suggests that day-night rhythms in the functional expression of subthreshold potassium (K + ) channels regulate daily oscillations in the rates of spontaneous action potential firing of neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in mammals. The K + conductance(s) driving these daily rhythms in repetitive firing rates, however, have not been identified. To test the hypothesis that subthreshold Kv12.1/Kv12.2-encoded K + channels play a role, we obtained current-clamp recordings from SCN neurons in slices prepared from adult mice harboring targeted disruptions in the Kcnh8 (Kv12.1 -/- ) or Kcnh3 (Kv12.2 -/- ) locus. We found that mean nighttime repetitive firing rates were higher in Kv12.1 -/- and Kv12.2 -/- , than in wild type (WT), SCN neurons. In marked contrast, mean daytime repetitive firing rates were similar in Kv12.1 -/- , Kv12.2 -/- and WT SCN neurons, and the day-night difference in mean repetitive firing rates, a hallmark feature of WT SCN neurons, was eliminated in Kv12.1 -/- and Kv12.2 -/- SCN neurons. Similar results were obtained with in vivo shRNA-mediated acute knockdown of Kv12.1 or Kv12.2 in adult SCN neurons. Voltage-clamp experiments revealed that Kv12-encoded current densities in WT SCN neurons are higher at night than during the day. In addition, pharmacological block of Kv12-encoded currents increased the mean repetitive firing rate of nighttime, but not daytime, in WT SCN neurons. Dynamic clamp-mediated subtraction of modeled Kv12-encoded currents also selectively increased the mean repetitive firing rates of nighttime WT SCN neurons. Despite the elimination of nighttime decrease in the mean repetitive firing rates of SCN neurons, however, locomotor (wheel-running) activity remained rhythmic in Kv12.1 -/- , Kv12.2 -/- , Kv12.1-targeted shRNA-expressing, and Kv12.2-targeted shRNA-expressing animals.
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Affiliation(s)
- Tracey O. Hermanstyne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | - Nien-Du Yang
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO
| | | | - Xiaofan Li
- Department of Biology, The Pennsylvania State University, University Park, PA
| | - Rebecca L. Mellor
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO
| | - Timothy Jegla
- Department of Biology, The Pennsylvania State University, University Park, PA
| | - Erik D. Herzog
- Department of Biology, Washington University, St. Louis, MO
| | - Jeanne M. Nerbonne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO
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5
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Morphofunctional State and Circadian Rhythms of the Liver of Female Rats under the Influence of Chronic Alcohol Intoxication and Constant Lighting. Int J Mol Sci 2022; 23:ijms231810744. [PMID: 36142658 PMCID: PMC9502101 DOI: 10.3390/ijms231810744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
A separate and combined effect of constant illumination and chronic alcohol intoxication (CAI) on diurnal dynamics of micromorphometric parameters of hepatocytes in female Wistar rats and p53, Ki-67, PER2, BMAL1, and ADH5 expression in these cells were studied. The increase in apoptotic activity and proliferation in all animals under the action of chronodestructors is shown. All experimental animals showed a decrease in BMAL1 expression and increase in PER2 expression; ADH5 is overexpressed under the influence of ethanol. Circadian rhythms (CRs) of BMAL1, PER2, p53, and Ki-67 expression persist in all groups, except combined action of chronodestructors, and ADH5 CRs persist in all groups—thus, these rhythms in females are quite stable. CRs of the hepatocyte nuclei area are preserved in all the studied groups, although they undergo a significant shift. At the same time, the CRs of the hepatocyte area are destroyed under the action of light, both independently and in combination with CAI, and the CR of the nuclear-cytoplasmic ratio (NCR) is destroyed by exposure to CAI. It can be assumed that CRs of the hepatocyte area are significantly affected by dark deprivation and NCR rhythm is sensitive to ethanol consumption, while the stability of studied genes’ expression rhythms at separate influences of studied chronodestructors is maintained by yet unknown adaptation mechanisms. It is necessary to note that, according to our previous studies of male rats, rat females show significantly greater stability of the studied CRs.
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Goltsev AV, Wright EAP, Mendes JFF, Yoon S. Generation and Disruption of Circadian Rhythms in the Suprachiasmatic Nucleus: A Core-Shell Model. J Biol Rhythms 2022; 37:545-561. [PMID: 35848398 PMCID: PMC9452856 DOI: 10.1177/07487304221107834] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We focus our research on how the core-shell organization controls behavior of the
suprachiasmatic nucleus (SCN), how the core and shell are synchronized to the
environment, what impact they have on the behavior of the SCN under different
lighting conditions, and what mechanisms disrupt synchronization. To this end,
we use a reduced Kuramoto model, with parameters inferred from experimental
observations and calibrated for mice, and perform a detailed comparison between
the model and experimental data under light-dark (LD), dark-dark (DD), and
light-light (LL) conditions. The operating limits of free-running and entrained
SCN activity under symmetric LD cycles are analyzed, with particular focus on
the phenomena of anticipation and dissociation. Results reveal that the
core-shell organization of the SCN enables anticipation of future events over
circadian cycles. The model predicts the emergence of a second (dissociated)
rhythm for large and small LD periods. Our results are in good qualitative and
quantitative agreement with experimental observations of circadian dissociation.
We further describe SCN activity under LL conditions and show that our model
satisfies Aschoff’s first rule, according to which the endogenous free-running
circadian period observed under complete darkness will shorten in diurnal
animals and lengthen in nocturnal animals under constant light. Our results
strongly suggest that the Kuramoto model captures essential features of
synchronization and entrainment in the SCN. Moreover, our approach is easily
extendible to an arbitrary number of groups, with dynamics described by explicit
equations for the group phase and synchronization index. Viewed together, the
reduced Kuramoto model presents itself as a useful tool for exploring open
problems in the study of circadian rhythms, one that can account for evolving
views of the circadian system’s organization, including peripheral clocks and
inter-hemispheric interaction, and can be translated to other nocturnal and
diurnal animals, including humans.
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Affiliation(s)
| | - Edgar A P Wright
- Department of Physics & I3N, University of Aveiro, Aveiro, Portugal
| | - José F F Mendes
- Department of Physics & I3N, University of Aveiro, Aveiro, Portugal
| | - Sooyeon Yoon
- Department of Physics & I3N, University of Aveiro, Aveiro, Portugal
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Schroder EA, Ono M, Johnson SR, Rozmus ER, Burgess DE, Esser KA, Delisle BP. The role of the cardiomyocyte circadian clocks in ion channel regulation and cardiac electrophysiology. J Physiol 2022; 600:2037-2048. [PMID: 35301719 PMCID: PMC9980729 DOI: 10.1113/jp282402] [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] [Received: 11/19/2021] [Accepted: 03/04/2022] [Indexed: 11/08/2022] Open
Abstract
Daily variations in cardiac electrophysiology and the incidence for different types of arrhythmias reflect ≈24 h changes in the environment, behaviour and internal circadian rhythms. This article focuses on studies that use animal models to separate the impact that circadian rhythms, as well as changes in the environment and behaviour, have on 24 h rhythms in heart rate and ventricular repolarization. Circadian rhythms are initiated at the cellular level by circadian clocks, transcription-translation feedback loops that cycle with a periodicity of 24 h. Several studies now show that the circadian clock in cardiomyocytes regulates the expression of cardiac ion channels by multiple mechanisms; underlies time-of-day changes in sinoatrial node excitability/intrinsic heart rate; and limits the duration of the ventricular action potential waveform. However, the 24 h rhythms in heart rate and ventricular repolarization are primarily driven by autonomic signalling. A functional role for the cardiomyocyte circadian clock appears to buffer the heart against perturbations. For example, the cardiomyocyte circadian clock limits QT-interval prolongation (especially at slower heart rates), and it may facilitate the realignment of the 24 h rhythm in heart rate to abrupt changes in the light cycle. Additional studies show that modifying rhythmic behaviours (including feeding behaviour) can dramatically impact the 24 h rhythms in heart rate and ventricular repolarization. If these mechanisms are conserved, these studies suggest that targeting endogenous circadian mechanisms in the heart, as well as modifying the timing of certain rhythmic behaviours, could emerge as therapeutic strategies to support heart function against perturbations and regulate 24 h rhythms in cardiac electrophysiology.
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Affiliation(s)
- Elizabeth A. Schroder
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298,Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, University of Kentucky, 740 S. Limestone Street, L543, Lexington, KY 40536-0284
| | - Makoto Ono
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
| | - Sidney R. Johnson
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
| | - Ezekiel R. Rozmus
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
| | - Don E. Burgess
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
| | - Karyn A. Esser
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA
| | - Brian P. Delisle
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
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Reinhard N, Schubert FK, Bertolini E, Hagedorn N, Manoli G, Sekiguchi M, Yoshii T, Rieger D, Helfrich-Förster C. The Neuronal Circuit of the Dorsal Circadian Clock Neurons in Drosophila melanogaster. Front Physiol 2022; 13:886432. [PMID: 35574472 PMCID: PMC9100938 DOI: 10.3389/fphys.2022.886432] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 03/28/2022] [Indexed: 11/30/2022] Open
Abstract
Drosophila’s dorsal clock neurons (DNs) consist of four clusters (DN1as, DN1ps, DN2s, and DN3s) that largely differ in size. While the DN1as and the DN2s encompass only two neurons, the DN1ps consist of ∼15 neurons, and the DN3s comprise ∼40 neurons per brain hemisphere. In comparison to the well-characterized lateral clock neurons (LNs), the neuroanatomy and function of the DNs are still not clear. Over the past decade, numerous studies have addressed their role in the fly’s circadian system, leading to several sometimes divergent results. Nonetheless, these studies agreed that the DNs are important to fine-tune activity under light and temperature cycles and play essential roles in linking the output from the LNs to downstream neurons that control sleep and metabolism. Here, we used the Flybow system, specific split-GAL4 lines, trans-Tango, and the recently published fly connectome (called hemibrain) to describe the morphology of the DNs in greater detail, including their synaptic connections to other clock and non-clock neurons. We show that some DN groups are largely heterogenous. While certain DNs are strongly connected with the LNs, others are mainly output neurons that signal to circuits downstream of the clock. Among the latter are mushroom body neurons, central complex neurons, tubercle bulb neurons, neurosecretory cells in the pars intercerebralis, and other still unidentified partners. This heterogeneity of the DNs may explain some of the conflicting results previously found about their functionality. Most importantly, we identify two putative novel communication centers of the clock network: one fiber bundle in the superior lateral protocerebrum running toward the anterior optic tubercle and one fiber hub in the posterior lateral protocerebrum. Both are invaded by several DNs and LNs and might play an instrumental role in the clock network.
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Affiliation(s)
- Nils Reinhard
- Julius Maximilian University of Würzburg, Würzburg, Germany
| | | | - Enrico Bertolini
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Würzburg, Germany
| | | | - Giulia Manoli
- Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Manabu Sekiguchi
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Dirk Rieger
- Julius Maximilian University of Würzburg, Würzburg, Germany
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9
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Rosi-Andersen A, Meister L, Graham B, Brown S, Bryant R, Ehlers A, Kleim B. Circadian influence on intrusive re-experiencing in trauma survivors' daily lives. Eur J Psychotraumatol 2022; 13:1899617. [PMID: 35295874 PMCID: PMC8920362 DOI: 10.1080/20008198.2021.1899617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The core clinical feature of posttraumatic stress disorder (PTSD) is recurrent re-experiencing in form of intrusive memories. While a great number of biological processes are regulated by sleep and internal biological clocks, the effect of 24-hour biological cycles, named circadian rhythm, has not been investigated in the context of intrusive memories. OBJECTIVE Here we examined effects of time of day on frequency and characteristics of intrusive re-experiencing. METHODS Fifty trauma survivors reported intrusive memories for 7 consecutive days using ecological momentary assessment in their daily life. We investigated (i) time-of-day dependent effects on frequency and distribution of intrusive re-experiencing in the overall sample as well as in PTSD versus non-PTSD and (ii) time-of-day dependent effects on the memory characteristics intrusiveness, vividness, nowness and fear. RESULTS Intrusive memories showed a curvilinear pattern that peaked at 2pm. Intrusive memories in the PTSD group showed a constant level of intrusive re-experiencing in the afternoon and evening, whereas a descending slope was present in the non-PTSD group. In PTSD, intrusive memories might thus be experienced in a more time-scattered fashion throughout the day, indicating chronodisruption. Intrusion characteristics did not follow this pattern. CONCLUSION Although preliminary and based on a small sample size, these findings contribute to a better understanding of the everyday occurrence and characteristics of intrusive memories, and point to the added value of examining time-dependent effects, which can directly inform prevention and intervention science.
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Affiliation(s)
- Alex Rosi-Andersen
- Department of Psychology, University of Zurich, Zurich, Switzerland.,Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland.,Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Laura Meister
- Department of Psychology, University of Zurich, Zurich, Switzerland.,Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Belinda Graham
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Steven Brown
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Richard Bryant
- School of Psychology, University of New South Wales, Sydney, Australia
| | - Anke Ehlers
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Birgit Kleim
- Department of Psychology, University of Zurich, Zurich, Switzerland.,Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
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10
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Zheng W, Gu C, Yang H, Rohling JHT. Motif structure for the four subgroups within the suprachiasmatic nuclei affects its entrainment ability. Phys Rev E 2022; 105:014314. [PMID: 35193260 DOI: 10.1103/physreve.105.014314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Circadian rhythms of physiological and behavioral activities are regulated by a central clock. This clock is located in the bilaterally symmetrical suprachiasmatic nucleus (SCN) of mammals. Each nucleus contains a light-sensitive group of neurons, named the ventrolateral (VL) part, with the rest of the neurons being insensitive to light, named the dorsomedial (DM) group. While the coupling between the VL and DM subgroups have been investigated quite well, the communication among the four subgroups across the nuclei did not get a lot of attention. In this article, we theoretically analyzed seven motiflike connection patterns to investigate the network of the two nuclei of the SCN as a whole in relation to the function of the SCN. We investigated the entrainment ability of the SCN and found that the entrainment range is larger in the motifs containing a link between the two VL parts across the nuclei, but it is smaller in the motifs that contain a link between the two DM parts across the nuclei. The SCN may strengthen or weaken connections between the left and right nucleus to accomodate changes in external conditions, such as resynchronization after a jet lag, adjustment to photoperiod or for the aging SCN.
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Affiliation(s)
- Wenxin Zheng
- Business School, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Changgui Gu
- Business School, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
- Department of Molecular Cell Biology, Laboratory for Neurophysiology, Leiden University Medical Center, Leiden 2300RC, The Netherlands
| | - Huijie Yang
- Business School, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Jos H T Rohling
- Department of Molecular Cell Biology, Laboratory for Neurophysiology, Leiden University Medical Center, Leiden 2300RC, The Netherlands
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11
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Reinhard N, Bertolini E, Saito A, Sekiguchi M, Yoshii T, Rieger D, Helfrich-Förster C. The lateral posterior clock neurons (LPN) of Drosophila melanogaster express three neuropeptides and have multiple connections within the circadian clock network and beyond. J Comp Neurol 2021; 530:1507-1529. [PMID: 34961936 DOI: 10.1002/cne.25294] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 11/12/2022]
Abstract
Drosophila's lateral posterior neurons (LPNs) belong to a small group of circadian clock neurons that is so far not characterized in detail. Thanks to a new highly specific split-Gal4 line, here we describe LPNs' morphology in fine detail, their synaptic connections, daily bimodal expression of neuropeptides, and propose a putative role of this cluster in controlling daily activity and sleep patterns. We found that the three LPNs are heterogeneous. Two of the neurons with similar morphology arborize in the superior medial and lateral protocerebrum and most likely promote sleep. One unique, possibly wakefulness-promoting, neuron with wider arborizations extends from the superior lateral protocerebrum toward the anterior optic tubercle. Both LPN types exhibit manifold connections with the other circadian clock neurons, especially with those that control the flies' morning and evening activity (M- and E-neurons, respectively). In addition, they form synaptic connections with neurons of the mushroom bodies, the fan-shaped body, and with many additional still unidentified neurons. We found that both LPN types rhythmically express three neuropeptides, Allostatin A, Allostatin C, and Diuretic Hormone 31 with maxima in the morning and the evening. The three LPN neuropeptides may, furthermore, signal to the insect hormonal center in the pars intercerebralis and contribute to rhythmic modulation of metabolism, feeding, and reproduction. We discuss our findings in the light of anatomical details gained by the recently published hemibrain of a single female fly on the electron microscopic level and of previous functional studies concerning the LPN. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Nils Reinhard
- Neurobiology and Genetics, Biocenter, University of Würzburg, Germany
| | - Enrico Bertolini
- Neurobiology and Genetics, Biocenter, University of Würzburg, Germany
| | - Aika Saito
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Manabu Sekiguchi
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Dirk Rieger
- Neurobiology and Genetics, Biocenter, University of Würzburg, Germany
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12
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Kozlova MA, Kirillov YA, Makartseva LA, Chernov I, Areshidze DA. Morphofunctional State and Circadian Rhythms of the Liver under the Influence of Chronic Alcohol Intoxication and Constant Lighting. Int J Mol Sci 2021; 22:ijms222313007. [PMID: 34884810 PMCID: PMC8657715 DOI: 10.3390/ijms222313007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/25/2021] [Accepted: 11/29/2021] [Indexed: 01/10/2023] Open
Abstract
A study of the influence of chronic alcohol intoxication, constant illumination and their combined effects on the morphofunctional state of the rat liver and the circadian rhythms (CR) of the studied parameters of the organism was carried out. It was found that both alcohol and constant illumination caused significant changes in the structure of the liver, as well as in the circadian rhythmicity of micromorphometric parameters of hepatocytes, ALT, and total and direct bilirubin rhythms; however, the combined effects of ethanol and constant illumination had the most significant effect on the studied parameters of the organism. These two factors caused disturbances in the circadian rhythms of the micromorphometric parameters of hepatocytes, disruption of the circadian rhythms of total protein, albumin, AST, ALT, and direct and total bilirubin, as well as disturbances in the expression and rhythmicity of the studied clock genes against a background of the development of an inflammatory process in the liver.
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Affiliation(s)
- Maria A. Kozlova
- Laboratory of Cell Pathology, A.P. Avtsyn Research Institute of Human Morphology, 117218 Moscow, Russia; (M.A.K.); (Y.A.K.); (L.A.M.)
| | - Yuri A. Kirillov
- Laboratory of Cell Pathology, A.P. Avtsyn Research Institute of Human Morphology, 117218 Moscow, Russia; (M.A.K.); (Y.A.K.); (L.A.M.)
| | - Lyudmila A. Makartseva
- Laboratory of Cell Pathology, A.P. Avtsyn Research Institute of Human Morphology, 117218 Moscow, Russia; (M.A.K.); (Y.A.K.); (L.A.M.)
| | - Igor Chernov
- Department of Pathological Anatomy, Tyumen State Medical University, 625023 Tyumen, Russia;
| | - David A. Areshidze
- Laboratory of Cell Pathology, A.P. Avtsyn Research Institute of Human Morphology, 117218 Moscow, Russia; (M.A.K.); (Y.A.K.); (L.A.M.)
- Experimental Tumor Chemotherapy Group, Center for Screening and Preclinical Testing, Institute of Problems of Chemical Physics of the Russian Academy of Science, 142432 Chernogolovka, Russia
- Correspondence: ; Tel.: +7-909-643-37-56
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13
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Bano-Otalora B, Moye MJ, Brown T, Lucas RJ, Diekman CO, Belle MD. Daily electrical activity in the master circadian clock of a diurnal mammal. eLife 2021; 10:68179. [PMID: 34845984 PMCID: PMC8631794 DOI: 10.7554/elife.68179] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 10/09/2021] [Indexed: 11/13/2022] Open
Abstract
Circadian rhythms in mammals are orchestrated by a central clock within the suprachiasmatic nuclei (SCN). Our understanding of the electrophysiological basis of SCN activity comes overwhelmingly from a small number of nocturnal rodent species, and the extent to which these are retained in day-active animals remains unclear. Here, we recorded the spontaneous and evoked electrical activity of single SCN neurons in the diurnal rodent Rhabdomys pumilio, and developed cutting-edge data assimilation and mathematical modeling approaches to uncover the underlying ionic mechanisms. As in nocturnal rodents, R. pumilio SCN neurons were more excited during daytime hours. By contrast, the evoked activity of R. pumilio neurons included a prominent suppressive response that is not present in the SCN of nocturnal rodents. Our modeling revealed and subsequent experiments confirmed transient subthreshold A-type potassium channels as the primary determinant of this response, and suggest a key role for this ionic mechanism in optimizing SCN function to accommodate R. pumilio's diurnal niche.
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Affiliation(s)
- Beatriz Bano-Otalora
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom.,Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Matthew J Moye
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, United States.,Department of Quantitative Pharmacology and Pharmacometrics (QP2), Kenilworth, United States
| | - Timothy Brown
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom.,Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Robert J Lucas
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom.,Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Casey O Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, United States.,EPSRC Centre for Predictive Modelling in Healthcare, Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - Mino Dc Belle
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
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14
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Brain Clocks, Sleep, and Mood. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 34773227 DOI: 10.1007/978-3-030-81147-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
The suprachiasmatic nucleus houses the master clock, but the genes which encode the circadian clock components are also expressed throughout the brain. Here, we review how circadian clock transcription factors regulate neuromodulator systems such as histamine, dopamine, and orexin that promote arousal. These circadian transcription factors all lead to repression of the histamine, dopamine, and orexin systems during the sleep period, so ensuring integration with the ecology of the animal. If these transcription factors are deleted or mutated, in addition to the global disturbances in circadian rhythms, this causes a chronic up-regulation of neuromodulators leading to hyperactivity, elevated mood, and reduced sleep, which have been suggested to be states resembling mania.
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15
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Delisle BP, George AL, Nerbonne JM, Bass JT, Ripplinger CM, Jain MK, Hermanstyne TO, Young ME, Kannankeril PJ, Duffy JF, Goldhaber JI, Hall MH, Somers VK, Smolensky MH, Garnett CE, Anafi RC, Scheer FAJL, Shivkumar K, Shea SA, Balijepalli RC. Understanding Circadian Mechanisms of Sudden Cardiac Death: A Report From the National Heart, Lung, and Blood Institute Workshop, Part 2: Population and Clinical Considerations. Circ Arrhythm Electrophysiol 2021; 14:e010190. [PMID: 34719257 DOI: 10.1161/circep.121.010190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Sudden cardiac death (SCD) is the sudden, unexpected death due to abrupt loss of heart function secondary to cardiovascular disease. In certain populations living with cardiovascular disease, SCD follows a distinct 24-hour pattern in occurrence, suggesting day/night rhythms in behavior, the environment, and endogenous circadian rhythms result in daily spans of increased vulnerability. The National Heart, Lung, and Blood Institute convened a workshop, Understanding Circadian Mechanisms of Sudden Cardiac Death to identify fundamental questions regarding the role of the circadian rhythms in SCD. Part 2 summarizes research gaps and opportunities in the areas of population and clinical research identified in the workshop. Established research supports a complex interaction between circadian rhythms and physiological responses that increase the risk for SCD. Moreover, these physiological responses themselves are influenced by several biological variables, including the type of cardiovascular disease, sex, age, and genetics, as well as environmental factors. The emergence of new noninvasive biotechnological tools that continuously measure key cardiovascular variables, as well as the identification of biomarkers to assess circadian rhythms, hold promise for generating large-scale human data sets that will delineate which subsets of individuals are most vulnerable to SCD. Additionally, these data will improve our understanding of how people who suffer from circadian disruptions develop cardiovascular diseases that increase the risk for SCD. Emerging strategies to identify new biomarkers that can quantify circadian health (eg, environmental, behavioral, and internal misalignment) may lead to new interventions and therapeutic targets to prevent the progression of cardiovascular diseases that cause SCD.
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Affiliation(s)
- Brian P Delisle
- Department of Physiology, University of Kentucky, Lexington (B.P.D.)
| | - Alfred L George
- Department of Pharmacology (A.L.G.), Northwestern University, Feinberg School of Medicine, Chicago, IL
| | - Jeanne M Nerbonne
- Cardiovascular Division, and Developmental Biology, Departments of Medicine (J.M.N.), Washington University School of Medicine, St Louis, MO
| | - Joseph T Bass
- Department of Medicine (J.T.B.), Northwestern University, Feinberg School of Medicine, Chicago, IL
| | | | - Mukesh K Jain
- Department of Medicine, Case Western Reserve University, Cleveland, OH (M.K.J.)
| | - Tracey O Hermanstyne
- Department of Developmental Biology (T.O.H.), Washington University School of Medicine, St Louis, MO
| | - Martin E Young
- Department of Medicine, University of Alabama, Birmingham (M.E.Y.)
| | - Prince J Kannankeril
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN (P.J.K.)
| | - Jeanne F Duffy
- Department of Medicine (J.F.D.), Harvard Medical School, Boston, MA
| | - Joshua I Goldhaber
- Department of Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA (J.I.G.)
| | - Martica H Hall
- Department of Psychiatry, University of Pittsburgh, PA (M.H.H.)
| | | | | | | | - Ron C Anafi
- Department of Medicine and Center for Sleep and Circadian Neurobiology, University of Pennsylvania Perelman School of Medicine, Philadelphia (R.C.A.)
| | - Frank A J L Scheer
- Division of Sleep Medicine (F.A.J.L.S.), Harvard Medical School, Boston, MA
| | - Kalyanam Shivkumar
- Departement of Medicine, David Greffen School of Medicine, University of California, Los Angeles (K.S.)
| | - Steven A Shea
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland (S.A.S.)
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16
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Delisle BP, George AL, Nerbonne JM, Bass JT, Ripplinger CM, Jain MK, Hermanstyne TO, Young ME, Kannankeril PJ, Duffy JF, Goldhaber JI, Hall MH, Somers VK, Smolensky MH, Garnett CE, Anafi RC, Scheer FA, Shivkumar K, Shea SA, Balijepalli RC. Understanding Circadian Mechanisms of Sudden Cardiac Death: A Report From the National Heart, Lung, and Blood Institute Workshop, Part 1: Basic and Translational Aspects. Circ Arrhythm Electrophysiol 2021; 14:e010181. [PMID: 34719240 PMCID: PMC8815462 DOI: 10.1161/circep.121.010181] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Sudden cardiac death (SCD), the unexpected death due to acquired or genetic cardiovascular disease, follows distinct 24-hour patterns in occurrence. These 24-hour patterns likely reflect daily changes in arrhythmogenic triggers and the myocardial substrate caused by day/night rhythms in behavior, the environment, and endogenous circadian mechanisms. To better address fundamental questions regarding the circadian mechanisms, the National Heart, Lung, and Blood Institute convened a workshop, Understanding Circadian Mechanisms of Sudden Cardiac Death. We present a 2-part report of findings from this workshop. Part 1 summarizes the workshop and serves to identify research gaps and opportunities in the areas of basic and translational research. Among the gaps was the lack of standardization in animal studies for reporting environmental conditions (eg, timing of experiments relative to the light dark cycle or animal housing temperatures) that can impair rigor and reproducibility. Workshop participants also pointed to uncertainty regarding the importance of maintaining normal circadian rhythmic synchrony and the potential pathological impact of desynchrony on SCD risk. One related question raised was whether circadian mechanisms can be targeted to reduce SCD risk. Finally, the experts underscored the need for studies aimed at determining the physiological importance of circadian clocks in the many different cell types important to normal heart function and SCD. Addressing these gaps could lead to new therapeutic approaches/molecular targets that can mitigate the risk of SCD not only at certain times but over the entire 24-hour period.
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Affiliation(s)
| | - Alfred L. George
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL
| | - Jeanne M. Nerbonne
- Departments of Medicine, Cardiovascular Division, and Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | - Joseph T. Bass
- Department of Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL
| | | | - Mukesh K. Jain
- Department of Medicine, Case Western Reserve University, Cleveland, OH
| | - Tracey O. Hermanstyne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | - Martin E. Young
- Department of Medicine, University of Alabama, Birmingham, AL
| | | | | | | | - Martica H. Hall
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | | | | | | | - Ron C. Anafi
- Department of Medicine and Center for Sleep and Circadian Neurobiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | | | - Kalyanam Shivkumar
- Departement of Medicine, David Greffen School of Medicine at UCLA, Los Angeles, CA
| | - Steven A. Shea
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR
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17
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Yoon S, Wright EAP, Mendes JFF, Goltsev AV. Impact of field heterogeneity on the dynamics of the forced Kuramoto model. Phys Rev E 2021; 104:024313. [PMID: 34525638 DOI: 10.1103/physreve.104.024313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/20/2021] [Indexed: 11/07/2022]
Abstract
We studied the impact of field heterogeneity on entrainment in a system of uniformly interacting phase oscillators. Field heterogeneity is shown to induce dynamical heterogeneity in the system. In effect, the heterogeneous field partitions the system into interacting groups of oscillators that feel the same local field strength and phase. Based on numerical and analytical analysis of the explicit dynamical equations derived from the periodically forced Kuramoto model, we found that the heterogeneous field can disrupt entrainment at different field frequencies when compared to the homogeneous field. This transition occurs when the phase- and frequency-locked synchronization between groups of oscillators is broken at a critical field frequency, causing each group to enter a new dynamical state (disrupted state). Strikingly, it is shown that disrupted dynamics can differ between groups.
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Affiliation(s)
- S Yoon
- Department of Physics & I3N, University of Aveiro, 3810-193 Aveiro, Portugal
| | - E A P Wright
- Department of Physics & I3N, University of Aveiro, 3810-193 Aveiro, Portugal
| | - J F F Mendes
- Department of Physics & I3N, University of Aveiro, 3810-193 Aveiro, Portugal
| | - A V Goltsev
- Department of Physics & I3N, University of Aveiro, 3810-193 Aveiro, Portugal.,A.F. Ioffe Physico-Technical Institute, 194021 St. Petersburg, Russia
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18
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Gu C, Li J, Zhou J, Yang H, Rohling J. Network Structure of the Master Clock Is Important for Its Primary Function. Front Physiol 2021; 12:678391. [PMID: 34483953 PMCID: PMC8415478 DOI: 10.3389/fphys.2021.678391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
A master clock located in the suprachiasmatic nucleus (SCN) regulates the circadian rhythm of physiological and behavioral activities in mammals. The SCN has two main functions in the regulation: an endogenous clock produces the endogenous rhythmic signal in body rhythms, and a calibrator synchronizes the body rhythms to the external light-dark cycle. These two functions have been determined to depend on either the dynamic behaviors of individual neurons or the whole SCN neuronal network. In this review, we first introduce possible network structures for the SCN, as revealed by time series analysis from real experimental data. It was found that the SCN network is heterogeneous and sparse, that is, the average shortest path length is very short, some nodes are hubs with large node degrees but most nodes have small node degrees, and the average node degree of the network is small. Secondly, the effects of the SCN network structure on the SCN function are reviewed based on mathematical models of the SCN network. It was found that robust rhythms with large amplitudes, a high synchronization between SCN neurons and a large entrainment ability exists mainly in small-world and scale-free type networks, but not other types. We conclude that the SCN most probably is an efficient small-world type or scale-free type network, which drives SCN function.
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Affiliation(s)
- Changgui Gu
- Business School, University of Shanghai for Science and Technology, Shanghai, China
| | - Jiahui Li
- Business School, University of Shanghai for Science and Technology, Shanghai, China
| | - Jian Zhou
- Business School, University of Shanghai for Science and Technology, Shanghai, China
| | - Huijie Yang
- Business School, University of Shanghai for Science and Technology, Shanghai, China
| | - Jos Rohling
- Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
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19
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Schroder EA, Wayland JL, Samuels KM, Shah SF, Burgess DE, Seward T, Elayi CS, Esser KA, Delisle BP. Cardiomyocyte Deletion of Bmal1 Exacerbates QT- and RR-Interval Prolongation in Scn5a +/ΔKPQ Mice. Front Physiol 2021; 12:681011. [PMID: 34248669 PMCID: PMC8265216 DOI: 10.3389/fphys.2021.681011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/18/2021] [Indexed: 11/21/2022] Open
Abstract
Circadian rhythms are generated by cell autonomous circadian clocks that perform a ubiquitous cellular time-keeping function and cell type-specific functions important for normal physiology. Studies show inducing the deletion of the core circadian clock transcription factor Bmal1 in adult mouse cardiomyocytes disrupts cardiac circadian clock function, cardiac ion channel expression, slows heart rate, and prolongs the QT-interval at slow heart rates. This study determined how inducing the deletion of Bmal1 in adult cardiomyocytes impacted the in vivo electrophysiological phenotype of a knock-in mouse model for the arrhythmogenic long QT syndrome (Scn5a+/ΔKPQ). Electrocardiographic telemetry showed inducing the deletion of Bmal1 in the cardiomyocytes of mice with or without the ΔKPQ-Scn5a mutation increased the QT-interval at RR-intervals that were ≥130 ms. Inducing the deletion of Bmal1 in the cardiomyocytes of mice with or without the ΔKPQ-Scn5a mutation also increased the day/night rhythm-adjusted mean in the RR-interval, but it did not change the period, phase or amplitude. Compared to mice without the ΔKPQ-Scn5a mutation, mice with the ΔKPQ-Scn5a mutation had reduced heart rate variability (HRV) during the peak of the day/night rhythm in the RR-interval. Inducing the deletion of Bmal1 in cardiomyocytes did not affect HRV in mice without the ΔKPQ-Scn5a mutation, but it did increase HRV in mice with the ΔKPQ-Scn5a mutation. The data demonstrate that deleting Bmal1 in cardiomyocytes exacerbates QT- and RR-interval prolongation in mice with the ΔKPQ-Scn5a mutation.
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Affiliation(s)
- Elizabeth A Schroder
- Department of Physiology, University of Kentucky, Lexington, KY, United States.,Internal Medicine and Pulmonary, University of Kentucky, Lexington, KY, United States
| | - Jennifer L Wayland
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Kaitlyn M Samuels
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Syed F Shah
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Don E Burgess
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Tanya Seward
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | | | - Karyn A Esser
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, United States
| | - Brian P Delisle
- Department of Physiology, University of Kentucky, Lexington, KY, United States
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20
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Gumarova L, Farah Z, Tyutenova A, Gumarova Z, Sackett-Lundeen L, Kazlausky T, Cornelissen Guillaume G. Comparative analysis of circadian rhythms of hemodynamics and physical activity. BIOL RHYTHM RES 2021. [DOI: 10.1080/09291016.2021.1922827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Lyazzat Gumarova
- Department of Biophysics, Biomedicine and Neuroscience, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Zainab Farah
- Department of Integrative Biology and Physiology, Halberg Chronobiology Center, University of Minnesota, Minneapolis, MN, USA
| | - Alima Tyutenova
- Department of Biophysics, Biomedicine and Neuroscience, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Zhanna Gumarova
- Department of chemical disciplines, West Kazakhstan Marat Ospanov State Medical University, Aktobe, Kazakhstan
| | - Linda Sackett-Lundeen
- Department of Integrative Biology and Physiology, Halberg Chronobiology Center, University of Minnesota, Minneapolis, MN, USA
| | | | - Germaine Cornelissen Guillaume
- Department of Integrative Biology and Physiology, Halberg Chronobiology Center, University of Minnesota, Minneapolis, MN, USA
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21
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Buijink MR, Michel S. A multi-level assessment of the bidirectional relationship between aging and the circadian clock. J Neurochem 2021; 157:73-94. [PMID: 33370457 PMCID: PMC8048448 DOI: 10.1111/jnc.15286] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022]
Abstract
The daily temporal order of physiological processes and behavior contribute to the wellbeing of many organisms including humans. The central circadian clock, which coordinates the timing within our body, is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Like in other parts of the brain, aging impairs the SCN function, which in turn promotes the development and progression of aging-related diseases. We here review the impact of aging on the different levels of the circadian clock machinery-from molecules to organs-with a focus on the role of the SCN. We find that the molecular clock is less effected by aging compared to other cellular components of the clock. Proper rhythmic regulation of intracellular signaling, ion channels and neuronal excitability of SCN neurons are greatly disturbed in aging. This suggests a disconnection between the molecular clock and the electrophysiology of these cells. The neuronal network of the SCN is able to compensate for some of these cellular deficits. However, it still results in a clear reduction in the amplitude of the SCN electrical rhythm, suggesting a weakening of the output timing signal. Consequently, other brain areas and organs not only show aging-related deficits in their own local clocks, but also receive a weaker systemic timing signal. The negative spiral completes with the weakening of positive feedback from the periphery to the SCN. Consequently, chronotherapeutic interventions should aim at strengthening overall synchrony in the circadian system using life-style and/or pharmacological approaches.
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Affiliation(s)
- M. Renate Buijink
- Department of Cellular and Chemical BiologyLaboratory for NeurophysiologyLeiden University Medical CenterLeidenthe Netherlands
| | - Stephan Michel
- Department of Cellular and Chemical BiologyLaboratory for NeurophysiologyLeiden University Medical CenterLeidenthe Netherlands
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22
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Dere D, Zlomuzica A, Dere E. Channels to consciousness: a possible role of gap junctions in consciousness. Rev Neurosci 2020; 32:/j/revneuro.ahead-of-print/revneuro-2020-0012/revneuro-2020-0012.xml. [PMID: 32853172 DOI: 10.1515/revneuro-2020-0012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 06/26/2020] [Indexed: 12/20/2022]
Abstract
The neurophysiological basis of consciousness is still unknown and one of the most challenging questions in the field of neuroscience and related disciplines. We propose that consciousness is characterized by the maintenance of mental representations of internal and external stimuli for the execution of cognitive operations. Consciousness cannot exist without working memory, and it is likely that consciousness and working memory share the same neural substrates. Here, we present a novel psychological and neurophysiological framework that explains the role of consciousness for cognition, adaptive behavior, and everyday life. A hypothetical architecture of consciousness is presented that is organized as a system of operation and storage units named platforms that are controlled by a consciousness center (central executive/online platform). Platforms maintain mental representations or contents, are entrusted with different executive functions, and operate at different levels of consciousness. The model includes conscious-mode central executive/online and mental time travel platforms and semiconscious steady-state and preconscious standby platforms. Mental representations or contents are represented by neural circuits and their support cells (astrocytes, oligodendrocytes, etc.) and become conscious when neural circuits reverberate, that is, fire sequentially and continuously with relative synchronicity. Reverberatory activity in neural circuits may be initiated and maintained by pacemaker cells/neural circuit pulsars, enhanced electronic coupling via gap junctions, and unapposed hemichannel opening. The central executive/online platform controls which mental representations or contents should become conscious by recruiting pacemaker cells/neural network pulsars, the opening of hemichannels, and promoting enhanced neural circuit coupling via gap junctions.
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Affiliation(s)
- Dorothea Dere
- Département UMR 8256 Adaptation Biologique et Vieillissement, Sorbonne Université, Institut de Biologie Paris-Seine, (IBPS), UFR des Sciences de la Vie, Campus Pierre et Marie Curie, Bâtiment B, 9 quai Saint Bernard, F-75005 Paris Cedex, France
| | - Armin Zlomuzica
- Faculty of Psychology, Behavioral and Clinical Neuroscience, University of Bochum, Massenbergstraße 9-13, D-44787 Bochum, Germany
| | - Ekrem Dere
- Département UMR 8256 Adaptation Biologique et Vieillissement, Sorbonne Université, Institut de Biologie Paris-Seine, (IBPS), UFR des Sciences de la Vie, Campus Pierre et Marie Curie, Bâtiment B, 9 quai Saint Bernard, F-75005 Paris Cedex, France
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23
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Werckenthin A, Huber J, Arnold T, Koziarek S, Plath MJA, Plath JA, Stursberg O, Herzel H, Stengl M. Neither per, nor tim1, nor cry2 alone are essential components of the molecular circadian clockwork in the Madeira cockroach. PLoS One 2020; 15:e0235930. [PMID: 32750054 PMCID: PMC7402517 DOI: 10.1371/journal.pone.0235930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/25/2020] [Indexed: 12/30/2022] Open
Abstract
Circadian clocks control rhythms in physiology and behavior entrained to 24 h light-dark cycles. Despite of conserved general schemes, molecular circadian clockworks differ between insect species. With RNA interference (RNAi) we examined an ancient circadian clockwork in a basic insect, the hemimetabolous Madeira cockroach Rhyparobia maderae. With injections of double-stranded RNA (dsRNA) of cockroach period (Rm´per), timeless 1 (Rm´tim1), or cryptochrome 2 (Rm´cry2) we searched for essential components of the clock´s core negative feedback loop. Single injections of dsRNA of each clock gene into adult cockroaches successfully and permanently knocked down respective mRNA levels within ~two weeks deleting daytime-dependent mRNA rhythms for Rm´per and Rm´cry2. Rm´perRNAi or Rm´cry2RNAi affected total mRNA levels of both genes, while Rm´tim1 transcription was independent of both, also keeping rhythmic expression. Unexpectedly, circadian locomotor activity of most cockroaches remained rhythmic for each clock gene knockdown employed. It expressed weakened rhythms and unchanged periods for Rm´perRNAi and shorter periods for Rm´tim1RNAi and Rm´cry2RNAi.As a hypothesis of the cockroach´s molecular clockwork, a basic network of switched differential equations was developed to model the oscillatory behavior of clock cells expressing respective clock genes. Data were consistent with two synchronized main groups of coupled oscillator cells, a leading (morning) oscillator, or a lagging (evening) oscillator that couple via mutual inhibition. The morning oscillators express shorter, the evening oscillators longer endogenous periods based on core feedback loops with either PER, TIM1, or CRY2/PER complexes as dominant negative feedback of the clockwork. We hypothesize that dominant morning oscillator cells with shorter periods express PER, but not CRY2, or TIM1 as suppressor of clock gene expression, while two groups of evening oscillator cells with longer periods either comprise TIM1 or CRY2/PER suppressing complexes. Modelling suggests that there is an additional negative feedback next to Rm´PER in cockroach morning oscillator cells.
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Affiliation(s)
- Achim Werckenthin
- Department of Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
| | - Jannik Huber
- Department of Control and System Theory, University of Kassel, Kassel, Germany
| | - Thordis Arnold
- Department of Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
| | - Susanne Koziarek
- Department of Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
| | - Marcus J. A. Plath
- Department of Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
| | - Jenny A. Plath
- Department of Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
| | - Olaf Stursberg
- Department of Control and System Theory, University of Kassel, Kassel, Germany
| | - Hanspeter Herzel
- Department of Theoretical Biology, Charité Berlin, Berlin, Germany
| | - Monika Stengl
- Department of Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
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24
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Gamble KL, Silver R. Circadian rhythmicity and the community of clockworkers. Eur J Neurosci 2019; 51:2314-2328. [PMID: 31814204 DOI: 10.1111/ejn.14626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/17/2019] [Accepted: 11/26/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rae Silver
- Department of Neuroscience, Barnard College, New York, NY, USA.,Department of Psychology, Columbia University, New York, NY, USA.,Department of Pathology and Cell Biology, Columbia University Health Sciences, New York, NY, USA
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25
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Komarzynski S, Bolborea M, Huang Q, Finkenstädt B, Lévi F. Predictability of individual circadian phase during daily routine for medical applications of circadian clocks. JCI Insight 2019; 4:130423. [PMID: 31430260 PMCID: PMC6795290 DOI: 10.1172/jci.insight.130423] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/13/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUNDCircadian timing of treatments can largely improve tolerability and efficacy in patients. Thus, drug metabolism and cell cycle are controlled by molecular clocks in each cell and coordinated by the core body temperature 24-hour rhythm, which is generated by the hypothalamic pacemaker. Individual circadian phase is currently estimated with questionnaire-based chronotype, center-of-rest time, dim light melatonin onset (DLMO), or timing of core body temperature (CBT) maximum (acrophase) or minimum (bathyphase).METHODSWe aimed at circadian phase determination and readout during daily routines in volunteers stratified by sex and age. We measured (a) chronotype, (b) every minute (q1min) CBT using 2 electronic pills swallowed 24 hours apart, (c) DLMO through hourly salivary samples from 1800 hours to bedtime, and (d) q1min accelerations and surface temperature at anterior chest level for 7 days, using a teletransmitting sensor. Circadian phases were computed using cosinor and hidden Markov modeling. Multivariate regression identified the combination of biomarkers that best predicted core temperature circadian bathyphase.RESULTSAmong the 33 participants, individual circadian phases were spread over 5 hours, 10 minutes (DLMO); 7 hours (CBT bathyphase); and 9 hours, 10 minutes (surface temperature acrophase). CBT bathyphase was accurately predicted, i.e., with an error less than 1 hour for 78.8% of the subjects, using a new digital health algorithm (INTime), combining time-invariant sex and chronotype score with computed center-of-rest time and surface temperature bathyphase (adjusted R2 = 0.637).CONCLUSIONINTime provided a continuous and reliable circadian phase estimate in real time. This model helps integrate circadian clocks into precision medicine and will enable treatment timing personalization following further validation.FUNDINGMedical Research Council, United Kingdom; AP-HP Foundation; and INSERM.
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Affiliation(s)
- Sandra Komarzynski
- Medical School, Warwick University, Coventry, United Kingdom.,INSERM-Warwick European Associated Laboratory, INSERM U935, Villejuif, France
| | - Matei Bolborea
- Medical School, Warwick University, Coventry, United Kingdom.,School of Life Sciences and
| | - Qi Huang
- Medical School, Warwick University, Coventry, United Kingdom.,Department of Statistics, Warwick University, Coventry, United Kingdom
| | - Bärbel Finkenstädt
- INSERM-Warwick European Associated Laboratory, INSERM U935, Villejuif, France.,Department of Statistics, Warwick University, Coventry, United Kingdom
| | - Francis Lévi
- Medical School, Warwick University, Coventry, United Kingdom.,INSERM-Warwick European Associated Laboratory, INSERM U935, Villejuif, France
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26
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Michel S, Meijer JH. From clock to functional pacemaker. Eur J Neurosci 2019; 51:482-493. [PMID: 30793396 PMCID: PMC7027845 DOI: 10.1111/ejn.14388] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/23/2019] [Accepted: 02/11/2019] [Indexed: 12/17/2022]
Abstract
In mammals, the central pacemaker that coordinates 24‐hr rhythms is located in the suprachiasmatic nucleus (SCN). Individual neurons of the SCN have a molecular basis for rhythm generation and hence, they function as cell autonomous oscillators. Communication and synchronization among these neurons are crucial for obtaining a coherent rhythm at the population level, that can serve as a pace making signal for brain and body. Hence, the ability of single SCN neurons to produce circadian rhythms is equally important as the ability of these neurons to synchronize one another, to obtain a bona fide pacemaker at the SCN tissue level. In this chapter we will discuss the mechanisms underlying synchronization, and plasticity herein, which allows adaptation to changes in day length. Furthermore, we will discuss deterioration in synchronization among SCN neurons in aging, and gain in synchronization by voluntary physical activity or exercise.
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Affiliation(s)
- Stephan Michel
- Group Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Johanna H Meijer
- Group Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
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27
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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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