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Perea-Rodríguez JP, Corley MK, de la Iglesia H, Fernandez-Duque E. Thermoenergetic challenges and daytime behavioural patterns of a wild cathemeral mammal. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2021.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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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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Abitbol K, Debiesse S, Molino F, Mesirca P, Bidaud I, Minami Y, Mangoni ME, Yagita K, Mollard P, Bonnefont X. Clock-dependent and system-driven oscillators interact in the suprachiasmatic nuclei to pace mammalian circadian rhythms. PLoS One 2017; 12:e0187001. [PMID: 29059248 PMCID: PMC5653358 DOI: 10.1371/journal.pone.0187001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/11/2017] [Indexed: 12/04/2022] Open
Abstract
Circadian clocks drive biological rhythms with a period of approximately 24 hours and keep in time with the outside world through daily resetting by environmental cues. While this external entrainment has been extensively investigated in the suprachiasmatic nuclei (SCN), the role of internal systemic rhythms, including daily fluctuations in core temperature or circulating hormones remains debated. Here, we show that lactating mice, which exhibit dampened systemic rhythms, possess normal molecular clockwork but impaired rhythms in both heat shock response gene expression and electrophysiological output in their SCN. This suggests that body rhythms regulate SCN activity downstream of the clock. Mathematical modeling predicts that systemic feedback upon the SCN functions as an internal oscillator that accounts for in vivo and ex vivo observations. Thus we are able to propose a new bottom-up hierarchical organization of circadian timekeeping in mammals, based on the interaction in the SCN between clock-dependent and system-driven oscillators.
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Affiliation(s)
- Karine Abitbol
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Ségolène Debiesse
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - François Molino
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
- Laboratoire Charles Coulomb, Université de Montpellier, CNRS UMR 5221, Montpellier, France
| | - Pietro Mesirca
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Isabelle Bidaud
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Yoichi Minami
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Matteo E. Mangoni
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Kazuhiro Yagita
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Patrice Mollard
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Xavier Bonnefont
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
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Jeong B, Hong JH, Kim H, Choe HK, Kim K, Lee KJ. Multi-stability of circadian phase wave within early postnatal suprachiasmatic nucleus. Sci Rep 2016; 6:21463. [PMID: 26891917 PMCID: PMC4759822 DOI: 10.1038/srep21463] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/20/2016] [Indexed: 11/09/2022] Open
Abstract
The suprachiasmatic nucleus (SCN) is a group of cells that functions as a biological master clock. In different SCN cells, oscillations of biochemical markers such as the expression-level of clock genes, are not synchronized but instead form slow circadian phase waves propagating over the whole cell population spatio-temporal struc- ture is a fixed property set by the anatomy of a given SCN. Here, we show that this is not the case in early postnatal SCN. Earlier studies presumed that their Based on bioluminescence imaging experiments with Per2-Luciferase mice SCN cultures which guided computer simulations of a realistic model of the SCN, we demonstrate that the wave is not unique but can be in various modes including phase- coherent oscillation, crescent-shaped wave, and most notably, a rotating pinwheel wave that conceptually resembles a wall clock with a rotating hand. Furthermore, mode transitions can be induced by a pulse of 38.5 °C temperature perturbation. Importantly, the waves support a significantly different period, suggesting that neither a spatially-fixed phase ordering nor a specialized pacemaker having a fixed period exist in these studied SCNs. These results lead to new important questions of what the observed multi-stability means for the proper function of an SCN and its arrhythmia.
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Affiliation(s)
- Byeongha Jeong
- Department of Physics, Korea University, Seoul, 136-713, Korea
| | - Jin Hee Hong
- Department of Physics, Korea University, Seoul, 136-713, Korea
| | - Hyun Kim
- Department of Physics, Korea University, Seoul, 136-713, Korea
| | - Han Kyoung Choe
- School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
| | - Kyungjin Kim
- School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
| | - Kyoung J Lee
- Department of Physics, Korea University, Seoul, 136-713, Korea
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Sládek M, Sumová A. Entrainment of spontaneously hypertensive rat fibroblasts by temperature cycles. PLoS One 2013; 8:e77010. [PMID: 24116198 PMCID: PMC3792033 DOI: 10.1371/journal.pone.0077010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 08/27/2013] [Indexed: 01/23/2023] Open
Abstract
The functional state of the circadian system of spontaneously hypertensive rats (SHR) differs in several characteristics from the functional state of normotensive Wistar rats. Some of these changes might be due to the compromised ability of the central pacemaker to entrain the peripheral clocks. Daily body temperature cycles represent one of the important cues responsible for the integrity of the circadian system, because these cycles are driven by the central pacemaker and are able to entrain the peripheral clocks. This study tested the hypothesis that the aberrant peripheral clock entrainment of SHR results from a compromised peripheral clock sensitivity to the daily temperature cycle resetting. Using cultured Wistar rat and SHR fibroblasts transfected with the circadian luminescence reporter Bmal1-dLuc, we demonstrated that two consecutive square-wave temperature cycles with amplitudes of 2.5°C are necessary and sufficient to restart the dampened oscillations and entrain the circadian clocks in both Wistar rat and SHR fibroblasts. We also generated a phase response curve to temperature cycles for fibroblasts of both rat strains. Although some of the data suggested a slight resistance of SHR fibroblasts to temperature entrainment, we concluded that the overall effect it too weak to be responsible for the differences between the SHR and Wistar in vivo circadian phenotype.
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Affiliation(s)
- Martin Sládek
- Department of Neurohumoral Regulations, Institute of Physiology Academy of Sciences of the Czech Republic v.v.i., Prague, Czech Republic
- * E-mail:
| | - Alena Sumová
- Department of Neurohumoral Regulations, Institute of Physiology Academy of Sciences of the Czech Republic v.v.i., Prague, Czech Republic
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Saini C, Morf J, Stratmann M, Gos P, Schibler U. Simulated body temperature rhythms reveal the phase-shifting behavior and plasticity of mammalian circadian oscillators. Genes Dev 2012; 26:567-80. [PMID: 22379191 DOI: 10.1101/gad.183251.111] [Citation(s) in RCA: 182] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The circadian pacemaker in the suprachiasmatic nuclei (SCN) of the hypothalamus maintains phase coherence in peripheral cells through metabolic, neuronal, and humoral signaling pathways. Here, we investigated the role of daily body temperature fluctuations as possible systemic cues in the resetting of peripheral oscillators. Using precise temperature devices in conjunction with real-time monitoring of the bioluminescence produced by circadian luciferase reporter genes, we showed that simulated body temperature cycles of mice and even humans, with daily temperature differences of only 3°C and 1°C, respectively, could gradually synchronize circadian gene expression in cultured fibroblasts. The time required for establishing the new steady-state phase depended on the reporter gene, but after a few days, the expression of each gene oscillated with a precise phase relative to that of the temperature cycles. Smooth temperature oscillations with a very small amplitude could synchronize fibroblast clocks over a wide temperature range, and such temperature rhythms were also capable of entraining gene expression cycles to periods significantly longer or shorter than 24 h. As revealed by genetic loss-of-function experiments, heat-shock factor 1 (HSF1), but not HSF2, was required for the efficient synchronization of fibroblast oscillators to simulated body temperature cycles.
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Affiliation(s)
- Camille Saini
- Department of Molecular Biology, National Centers of Competence in Research Frontiers in Genetics, Sciences III, University of Geneva, CH-1211 Geneva-4, Switzerland
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Buhr ED, Yoo SH, Takahashi JS. Phase-Resetting Sensitivity of the Suprachiasmatic Nucleus and Oscillator Amplitude. J Biol Rhythms 2011. [DOI: 10.1177/0748730411411679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The amplitude of a circadian oscillator influences its response to a phase-resetting stimulus. The suprachiasmatic nucleus (SCN) is unique among circadian clocks in mammals in that the network connections among its neurons confer robustness both in amplitude and in resilience to perturbations. With reduced coupling among SCN neurons, the SCN becomes more susceptible to external phase-shifting stimuli. Thus, stimuli of the same strength will elicit different responses from the same tissue under different states of internal coupling. In his letter, Ruby (2011 [this issue]) discusses potential causes for discrepancies in studies that report dissimilar responses of the SCN to temperature changes. Here, we propose that the differences are likely due to a species difference and a difference in oscillator amplitude. These differences more likely result from inherent differences between mice and rats than from experimental procedures.
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Affiliation(s)
- Ethan D. Buhr
- Department of Neurobiology and Physiology, Northwestern University, Evanston, IL
- Department of Ophthalmology, University of Washington, Seattle, WA
| | - Seung-Hee Yoo
- Department of Neurobiology and Physiology, Northwestern University, Evanston, IL
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX
| | - Joseph S. Takahashi
- Department of Neurobiology and Physiology, Northwestern University, Evanston, IL
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX
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