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Stevenson TJ. Defining the brain control of physiological stability. Horm Behav 2024; 164:105607. [PMID: 39059231 DOI: 10.1016/j.yhbeh.2024.105607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 06/28/2024] [Accepted: 07/18/2024] [Indexed: 07/28/2024]
Abstract
The last few decades have seen major advances in neurobiology and uncovered novel genetic and cellular substrates involved in the control of physiological set points. In this Review, I discuss the limitations in the definition of homeostatic set points established by Walter B Canon and highlight evidence that two other physiological systems, namely rheostasis and allostasis provide distinct inputs to independently modify set-point levels. Using data collected over the past decade, the hypothalamic and genetic basis of regulated changes in set-point values by rheostatic mechanisms are described. Then, the role of higher-order brain regions, such as hippocampal circuits, for experience-dependent, allostatic induced changes in set-points are outlined. I propose that these systems provide a hierarchical organization of physiological stability that exists to maintain set-point values. The hierarchical organization of physiology has direct implications for basic and medical research, and clinical practice.
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Affiliation(s)
- Tyler J Stevenson
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, United Kingdom of Great Britain and Northern Ireland.
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2
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Lakin-Thomas P. The Case for the Target of Rapamycin Pathway as a Candidate Circadian Oscillator. Int J Mol Sci 2023; 24:13307. [PMID: 37686112 PMCID: PMC10488232 DOI: 10.3390/ijms241713307] [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: 08/09/2023] [Revised: 08/23/2023] [Accepted: 08/25/2023] [Indexed: 09/10/2023] Open
Abstract
The molecular mechanisms that drive circadian (24 h) rhythmicity have been investigated for many decades, but we still do not have a complete picture of eukaryotic circadian systems. Although the transcription/translation feedback loop (TTFL) model has been the primary focus of research, there are many examples of circadian rhythms that persist when TTFLs are not functioning, and we lack any good candidates for the non-TTFL oscillators driving these rhythms. In this hypothesis-driven review, the author brings together several lines of evidence pointing towards the Target of Rapamycin (TOR) signalling pathway as a good candidate for a non-TTFL oscillator. TOR is a ubiquitous regulator of metabolism in eukaryotes and recent focus in circadian research on connections between metabolism and rhythms makes TOR an attractive candidate oscillator. In this paper, the evidence for a role for TOR in regulating rhythmicity is reviewed, and the advantages of TOR as a potential oscillator are discussed. Evidence for extensive feedback regulation of TOR provides potential mechanisms for a TOR-driven oscillator. Comparison with ultradian yeast metabolic cycles provides an example of a potential TOR-driven self-sustained oscillation. Unanswered questions and problems to be addressed by future research are discussed.
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Ono D, Wang H, Hung CJ, Wang HT, Kon N, Yamanaka A, Li Y, Sugiyama T. Network-driven intracellular cAMP coordinates circadian rhythm in the suprachiasmatic nucleus. SCIENCE ADVANCES 2023; 9:eabq7032. [PMID: 36598978 DOI: 10.1126/sciadv.abq7032] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
The mammalian central circadian clock, located in the suprachiasmatic nucleus (SCN), coordinates the timing of physiology and behavior to local time cues. In the SCN, second messengers, such as cAMP and Ca2+, are suggested to be involved in the input and/or output of the molecular circadian clock. However, the functional roles of second messengers and their dynamics in the SCN remain largely unclear. In the present study, we visualized the spatiotemporal patterns of circadian rhythms of second messengers and neurotransmitter release in the SCN. Here, we show that neuronal activity regulates the rhythmic release of vasoactive intestinal peptides from the SCN, which drives the circadian rhythms of intracellular cAMP in the SCN. Furthermore, optical manipulation of intracellular cAMP levels in the SCN shifts molecular and behavioral circadian rhythms. Together, our study demonstrates that intracellular cAMP is a key molecule in the organization of the SCN circadian neuronal network.
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Affiliation(s)
- Daisuke Ono
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Huan Wang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
| | - Chi Jung Hung
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Hsin-Tzu Wang
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Laboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Biological Sciences, School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Naohiro Kon
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Laboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Akihiro Yamanaka
- Chinese Institute for Brain Research (CIBR), Beijing, 102206, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
| | - Takashi Sugiyama
- Advanced Optics and Biological Engineering, Evident Corporation, Tokyo, Japan
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4
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Zheng Y, Pan L, Wang F, Yan J, Wang T, Xia Y, Yao L, Deng K, Zheng Y, Xia X, Su Z, Chen H, Lin J, Ding Z, Zhang K, Zhang M, Chen Y. Neural function of Bmal1: an overview. Cell Biosci 2023; 13:1. [PMID: 36593479 PMCID: PMC9806909 DOI: 10.1186/s13578-022-00947-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/19/2022] [Indexed: 01/04/2023] Open
Abstract
Bmal1 (Brain and muscle arnt-like, or Arntl) is a bHLH/PAS domain transcription factor central to the transcription/translation feedback loop of the biologic clock. Although Bmal1 is well-established as a major regulator of circadian rhythm, a growing number of studies in recent years have shown that dysfunction of Bmal1 underlies a variety of psychiatric, neurodegenerative-like, and endocrine metabolism-related disorders, as well as potential oncogenic roles. In this review, we systematically summarized Bmal1 expression in different brain regions, its neurological functions related or not to circadian rhythm and biological clock, and pathological phenotypes arising from Bmal1 knockout. This review also discusses oscillation and rhythmicity, especially in the suprachiasmatic nucleus, and provides perspective on future progress in Bmal1 research.
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Affiliation(s)
- Yuanjia Zheng
- grid.464402.00000 0000 9459 9325Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China ,grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lingyun Pan
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Feixue Wang
- grid.464402.00000 0000 9459 9325Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Jinglan Yan
- grid.464402.00000 0000 9459 9325Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Taiyi Wang
- grid.464402.00000 0000 9459 9325Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yucen Xia
- grid.464402.00000 0000 9459 9325Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Lin Yao
- grid.464402.00000 0000 9459 9325Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Kelin Deng
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yuqi Zheng
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiaoye Xia
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhikai Su
- grid.411866.c0000 0000 8848 7685The Second Clinical College, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong China
| | - Hongjie Chen
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jie Lin
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhenwei Ding
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Kaitong Zhang
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Meng Zhang
- grid.464402.00000 0000 9459 9325Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yongjun Chen
- grid.464402.00000 0000 9459 9325Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China ,grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China ,Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao Greater Bay Area, Guangzhou, China
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5
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McManus D, Polidarova L, Smyllie NJ, Patton AP, Chesham JE, Maywood ES, Chin JW, Hastings MH. Cryptochrome 1 as a state variable of the circadian clockwork of the suprachiasmatic nucleus: Evidence from translational switching. Proc Natl Acad Sci U S A 2022; 119:e2203563119. [PMID: 35976881 PMCID: PMC9407638 DOI: 10.1073/pnas.2203563119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The suprachiasmatic nucleus (SCN) of the hypothalamus is the principal clock driving circadian rhythms of physiology and behavior that adapt mammals to environmental cycles. Disruption of SCN-dependent rhythms compromises health, and so understanding SCN time keeping will inform management of diseases associated with modern lifestyles. SCN time keeping is a self-sustaining transcriptional/translational delayed feedback loop (TTFL), whereby negative regulators inhibit their own transcription. Formally, the SCN clock is viewed as a limit-cycle oscillator, the simplest being a trajectory of successive phases that progresses through two-dimensional space defined by two state variables mapped along their respective axes. The TTFL motif is readily compatible with limit-cycle models, and in Neurospora and Drosophila the negative regulators Frequency (FRQ) and Period (Per) have been identified as state variables of their respective TTFLs. The identity of state variables of the SCN oscillator is, however, less clear. Experimental identification of state variables requires reversible and temporally specific control over their abundance. Translational switching (ts) provides this, the expression of a protein of interest relying on the provision of a noncanonical amino acid. We show that the negative regulator Cryptochrome 1 (CRY1) fulfills criteria defining a state variable: ts-CRY1 dose-dependently and reversibly suppresses the baseline, amplitude, and period of SCN rhythms, and its acute withdrawal releases the TTFL to oscillate from a defined phase. Its effect also depends on its temporal pattern of expression, although constitutive ts-CRY1 sustained (albeit less stable) oscillations. We conclude that CRY1 has properties of a state variable, but may operate among several state variables within a multidimensional limit cycle.
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Affiliation(s)
- David McManus
- aNeurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Lenka Polidarova
- aNeurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Nicola J. Smyllie
- aNeurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Andrew P. Patton
- aNeurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Johanna E. Chesham
- aNeurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Elizabeth S. Maywood
- aNeurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Jason W. Chin
- bPNAC Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, United Kingdom
| | - Michael H. Hastings
- aNeurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
- 1To whom correspondence may be addressed.
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6
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A Pattern to Link Adenosine Signaling, Circadian System, and Potential Final Common Pathway in the Pathogenesis of Major Depressive Disorder. Mol Neurobiol 2022; 59:6713-6723. [PMID: 35999325 PMCID: PMC9525429 DOI: 10.1007/s12035-022-03001-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 08/07/2022] [Indexed: 11/18/2022]
Abstract
Several studies have reported separate roles of adenosine receptors and circadian clockwork in major depressive disorder. While less evidence exists for regulation of the circadian clock by adenosine signaling, a small number of studies have linked the adenosinergic system, the molecular circadian clock, and mood regulation. In this article, we review relevant advances and propose that adenosine receptor signaling, including canonical and other alternative downstream cellular pathways, regulates circadian gene expression, which in turn may underlie the pathogenesis of mood disorders. Moreover, we summarize the convergent point of these signaling pathways and put forward a pattern by which Homer1a expression, regulated by both cAMP-response element binding protein (CREB) and circadian clock genes, may be the final common pathogenetic mechanism in depression.
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7
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Feng D, Xiong Q, Zhang F, Shi X, Xu H, Wei W, Ai J, Yang L. Identification of a Novel Nomogram to Predict Progression Based on the Circadian Clock and Insights Into the Tumor Immune Microenvironment in Prostate Cancer. Front Immunol 2022; 13:777724. [PMID: 35154101 PMCID: PMC8829569 DOI: 10.3389/fimmu.2022.777724] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 01/10/2022] [Indexed: 02/05/2023] Open
Abstract
Background Currently, the impact of the circadian rhythm on the tumorigenesis and progression of prostate cancer (PCA) has yet to be understood. In this study, we first established a novel nomogram to predict PCA progression based on circadian clock (CIC)-related genes and provided insights into the tumor immune microenvironment. Methods The TCGA and Genecards databases were used to identify potential candidate genes. Lasso and Cox regression analyses were applied to develop a CIC-related gene signature. The tumor immune microenvironment was evaluated through appropriate statistical methods and the GSCALite database. Results Ten genes were identified to construct a gene signature to predict progression probability for patients with PCA. Patients with high-risk scores were more prone to progress than those with low-risk scores (hazard ratio (HR): 4.11, 95% CI: 2.66-6.37; risk score cut-off: 1.194). CLOCK, PER (1, 2, 3), CRY2, NPAS2, RORA, and ARNTL showed a higher correlation with anti-oncogenes, while CSNK1D and CSNK1E presented a greater relationship with oncogenes. Overall, patients with higher risk scores showed lower mRNA expression of PER1, PER2, and CRY2 and higher expression of CSNK1E. In general, tumor samples presented higher infiltration levels of macrophages, T cells and myeloid dendritic cells than normal samples. In addition, tumor samples had higher immune scores, lower stroma scores and lower microenvironment scores than normal samples. Notably, patients with higher risk scores were associated with significantly lower levels of neutrophils, NK cells, T helper type 1, and mast cells. There was a positive correlation between the risk score and the tumor mutation burden (TMB) score, and patients with higher TMB scores were more prone to progress than those with lower TMB scores. Likewise, we observed similar results regarding the correlation between the microsatellite instability (MSI) score and the risk score and the impact of the MSI score on the progression-free interval. We observed that anti-oncogenes presented a significantly positive correlation with PD-L1, PD-L2, TIGIT and SIGLEC15, especially PD-L2. Conclusion We identified ten prognosis-related genes as a promising tool for risk stratification in PCA patients from the fresh perspective of CIC.
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Affiliation(s)
- Dechao Feng
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Qiao Xiong
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Facai Zhang
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Xu Shi
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Hang Xu
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Wuran Wei
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Jianzhong Ai
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
| | - Lu Yang
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, China
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8
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Mogavero F, van Zwieten K, Buitelaar JK, Glennon JC, Henckens MJAG. Deviant circadian rhythmicity, corticosterone variability and trait testosterone levels in aggressive mice. Eur J Neurosci 2022; 55:1492-1503. [PMID: 35229387 PMCID: PMC9313802 DOI: 10.1111/ejn.15632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/30/2021] [Accepted: 02/17/2022] [Indexed: 11/30/2022]
Abstract
Although aggression has been linked to disturbances of circadian rhythm, insight into the neural substrate of this association is currently lacking. The suprachiasmatic nucleus (SCN) of the hypothalamus, the master circadian clock, is regulated by clock genes and known to influence the secretion of cortisosterone and testosterone, important hormones implicated in aggression. Here, we investigated deviations in the regulation of the locomotor circadian rhythm and hormonal levels in a mouse model of abnormal aggression. We tested aggressive BALB/cJ and control BALB/cByJ mice in the resident–intruder paradigm and compared them on their locomotor circadian rhythm during a 12 h light/12 h dark cycle and constant darkness. State (serum) corticosterone and trait (hair) corticosterone and testosterone levels were determined, and immunohistochemistry was performed to assess the expression of important clock proteins, PER1 and PER2, in the core and shell of the SCN at the start of their active phase. Compared with BALB/cByJ mice, aggressive BALB/cJ mice displayed: (1) a shorter free‐running period in constant darkness; (2) reduced state corticosterone variability between circadian peak and trough but no differences in corticosterone trait levels; (3) lower testosterone trait levels; (4) higher PER1 expression in the SCN shell with no changes in PER2 in either SCN subregion during the early dark phase. Together, these results suggest that aggressive BALB/cJ mice have disturbances in different components encompassing the circadian and hormonal cycle, emphasizing their value for future investigation of the causal relationship between SCN function, circadian clocks and aggression.
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Affiliation(s)
- F Mogavero
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - K van Zwieten
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - J K Buitelaar
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - J C Glennon
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - M J A G Henckens
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
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9
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Roemer RB, Irene Terry L, Booth DT, Walter GH. Insights from an ancient gymnosperm lineage: ambient temperature and light and the timing of thermogenesis in cycad cones. AMERICAN JOURNAL OF BOTANY 2022; 109:151-165. [PMID: 35025111 DOI: 10.1002/ajb2.1810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/08/2021] [Indexed: 06/14/2023]
Abstract
PREMISE Although maintaining the appropriate mid-day timing of the diel thermogenic events of cones of the dioecious cycads Macrozamia lucida and M. macleayi is central to the survival of both plant and pollinator in this obligate pollination mutualism, the nature of the underlying mechanism remains obscure. We investigated whether it is under circadian control. Circadian mechanisms control the timing of many ecologically important processes in angiosperms, yet only a few gymnosperms have been studied in this regard. METHODS We subjected cones to different ambient temperature and lighting regimens (constant temperature and darkness; stepwise cool/warm ambient temperatures in constant darkness; stepwise dark/light exposures at constant temperature) to determine whether the resulting timing of their thermogenic events was consistent with circadian control. RESULTS Cones exposed to constant ambient temperature and darkness generated multiple temperature peaks endogenously, with an average interpeak-temperature period of 20.7 (±0.20) h that is temperature-compensated (Q10 = 1.02). Exposure to 24-h ambient temperature cycles (12 h cool/12 h warm, constant darkness) yielded an interpeak-temperature period of 24.0 (±0.05) h, accurately and precisely replicating the ambient temperature period. Exposure to 24-h photo-cycles (12 h light/12 h dark, constant ambient temperature) yielded a shorter, more variable interpeak-temperature period of 23 (±0.23) h. CONCLUSIONS Our results indicate that cycad cone thermogenesis is under circadian clock control and differentially affected by ambient temperature and light cycles. Our data from cycads (an ancient gymnosperm lineage) adds to what little is known about circadian timing in gymnosperms, which have rarely been studied from the circadian perspective.
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Affiliation(s)
- Robert B Roemer
- Department of Mechanical Engineering, University of Utah, 1543 Rio Tinto Kennecott Mechanical Engineering Bldg., 1495 E., 100 S., Salt Lake City, UT, 84112, USA
| | - L Irene Terry
- School of Biological Sciences, University of Utah, 257 S. 1400 E., Salt Lake City, UT, 84112, USA
| | - David T Booth
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Gimme H Walter
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
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10
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Circadian regulation of apolipoprotein gene expression affects testosterone production in mouse testis. Theriogenology 2021; 174:9-19. [PMID: 34416563 DOI: 10.1016/j.theriogenology.2021.06.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 06/07/2021] [Accepted: 06/17/2021] [Indexed: 01/02/2023]
Abstract
The circadian clock system plays an important role in regulating testosterone synthesis in mammals. Male Bmal1-/- mice are infertile with low serum testosterone levels and decreased expression of testicular steroidogenic genes, suggesting that circadian clock genes regulate testosterone biosynthesis by activating steroidogenic gene transcription. However, whether the circadian clock regulates testosterone production via other genes remains unknown. Using Bmal1-/- mice and their wild-type (WT) siblings, we aimed to identify additional genes by which the circadian clock regulates testosterone synthesis. WT and Bmal1-/- mouse testes sections had similar normal morphologies, although there was a decrease in testicular spermatozoa in the Bmal1-/- mice. Low serum testosterone levels were detected in the Bmal1-/- mice. RNA sequencing identified 37 and 48 genes that were differentially expressed between WT and Bmal1-/- mouse testes at circadian time (CT2 and CT14), respectively. The cholesterol metabolism pathway was significantly enriched in the KEGG pathway analysis, and there was lower expression of three apolipoprotein genes (Apoa1, Apoa2, and Apoc3) at CT2 in the testes of Bmal1-/- mice than in those of WT mice. These decreases in Apoa1, Apoa2, and Apoc3 expression were verified by quantitative polymerase chain reaction analysis, which also revealed downregulation of the expression of the circadian clock (Per2, Dbp, and Nr1d1) and steroidogenic (StAR, Cyp11a1, and Hsd17b3) genes. The expression of circadian clock genes was relatively stable in WT mice over a 20-h period, whereas there was clear circadian rhythmic expression of Apoa1, Apoa2, Apoc3, StAR, Cyp11a1, Hsd3b2, and Hsd17b3. Bmal1-/- mice showed severely reduced expression of testicular circadian clock genes at three time points (CT4, CT12, and CT20), and a reduction in mRNA expression levels of Apo (Apoa1, Apoa2, and Apoc3) and steroidogenic (StAR, Cyp11a1, Hsd3b2, and Hsd17b3) genes. Oil Red O staining showed decreased lipid aggregation in the Leydig cells of Bmal1-/- mouse testes. Considering the vital role of Apo genes in high-density lipoprotein formation and cholesterol transport, the present data suggest that the circadian clock system regulates testosterone production by orchestrating the rhythmic expression of Apo genes. These data extend our understanding of the role of the circadian clock in regulating testosterone production in mammals.
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11
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Ralph MR, Shi SQ, Johnson CH, Houdek P, Shrestha TC, Crosby P, O’Neill JS, Sládek M, Stinchcombe AR, Sumová A. Targeted modification of the Per2 clock gene alters circadian function in mPer2luciferase (mPer2Luc) mice. PLoS Comput Biol 2021; 17:e1008987. [PMID: 34048425 PMCID: PMC8191895 DOI: 10.1371/journal.pcbi.1008987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 06/10/2021] [Accepted: 04/20/2021] [Indexed: 11/19/2022] Open
Abstract
Modification of the Per2 clock gene in mPer2Luc reporter mice significantly alters circadian function. Behavioral period in constant dark is lengthened, and dissociates into two distinct components in constant light. Rhythms exhibit increased bimodality, enhanced phase resetting to light pulses, and altered entrainment to scheduled feeding. Mechanistic mathematical modelling predicts that enhanced protein interactions with the modified mPER2 C-terminus, combined with differential clock regulation among SCN subregions, can account for effects on circadian behavior via increased Per2 transcript and protein stability. PER2::LUC produces greater suppression of CLOCK:BMAL1 E-box activity than PER2. mPer2Luc carries a 72 bp deletion in exon 23 of Per2, and retains a neomycin resistance cassette that affects rhythm amplitude but not period. The results show that mPer2Luc acts as a circadian clock mutation illustrating a need for detailed assessment of potential impacts of c-terminal tags in genetically modified animal models.
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Affiliation(s)
- Martin R. Ralph
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Shu-qun Shi
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Carl H. Johnson
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Pavel Houdek
- Laboratory of Biological Rhythms, Institute of Physiology, the Czech Academy of Sciences, Prague, Czech Republic
| | - Tenjin C. Shrestha
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Priya Crosby
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - John S. O’Neill
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Martin Sládek
- Laboratory of Biological Rhythms, Institute of Physiology, the Czech Academy of Sciences, Prague, Czech Republic
| | | | - Alena Sumová
- Laboratory of Biological Rhythms, Institute of Physiology, the Czech Academy of Sciences, Prague, Czech Republic
- * E-mail:
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12
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Putker M, Wong DCS, Seinkmane E, Rzechorzek NM, Zeng A, Hoyle NP, Chesham JE, Edwards MD, Feeney KA, Fischer R, Peschel N, Chen K, Vanden Oever M, Edgar RS, Selby CP, Sancar A, O’Neill JS. CRYPTOCHROMES confer robustness, not rhythmicity, to circadian timekeeping. EMBO J 2021; 40:e106745. [PMID: 33491228 PMCID: PMC8013833 DOI: 10.15252/embj.2020106745] [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: 09/09/2020] [Revised: 12/08/2020] [Accepted: 12/18/2020] [Indexed: 12/22/2022] Open
Abstract
Circadian rhythms are a pervasive property of mammalian cells, tissues and behaviour, ensuring physiological adaptation to solar time. Models of cellular timekeeping revolve around transcriptional feedback repression, whereby CLOCK and BMAL1 activate the expression of PERIOD (PER) and CRYPTOCHROME (CRY), which in turn repress CLOCK/BMAL1 activity. CRY proteins are therefore considered essential components of the cellular clock mechanism, supported by behavioural arrhythmicity of CRY-deficient (CKO) mice under constant conditions. Challenging this interpretation, we find locomotor rhythms in adult CKO mice under specific environmental conditions and circadian rhythms in cellular PER2 levels when CRY is absent. CRY-less oscillations are variable in their expression and have shorter periods than wild-type controls. Importantly, we find classic circadian hallmarks such as temperature compensation and period determination by CK1δ/ε activity to be maintained. In the absence of CRY-mediated feedback repression and rhythmic Per2 transcription, PER2 protein rhythms are sustained for several cycles, accompanied by circadian variation in protein stability. We suggest that, whereas circadian transcriptional feedback imparts robustness and functionality onto biological clocks, the core timekeeping mechanism is post-translational.
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Affiliation(s)
| | | | | | | | - Aiwei Zeng
- MRC Laboratory of Molecular BiologyCambridgeUK
| | | | | | - Mathew D Edwards
- MRC Laboratory of Molecular BiologyCambridgeUK
- Present address:
UCL Sainsbury Wellcome Centre for Neural Circuits and BehaviourLondonUK
| | | | | | | | - Ko‐Fan Chen
- Institute of NeurologyUniversity College LondonLondonUK
- Present address:
Department of Genetics and Genome BiologyUniversity of LeicesterLeicesterUK
| | | | | | - Christopher P Selby
- Department of Biochemistry and BiophysicsUniversity of North Carolina School of MedicineChapel HillNCUSA
| | - Aziz Sancar
- Department of Biochemistry and BiophysicsUniversity of North Carolina School of MedicineChapel HillNCUSA
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13
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Yan J, Kim YJ, Somers DE. Post-Translational Mechanisms of Plant Circadian Regulation. Genes (Basel) 2021; 12:325. [PMID: 33668215 PMCID: PMC7995963 DOI: 10.3390/genes12030325] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 12/15/2022] Open
Abstract
The molecular components of the circadian system possess the interesting feature of acting together to create a self-sustaining oscillator, while at the same time acting individually, and in complexes, to confer phase-specific circadian control over a wide range of physiological and developmental outputs. This means that many circadian oscillator proteins are simultaneously also part of the circadian output pathway. Most studies have focused on transcriptional control of circadian rhythms, but work in plants and metazoans has shown the importance of post-transcriptional and post-translational processes within the circadian system. Here we highlight recent work describing post-translational mechanisms that impact both the function of the oscillator and the clock-controlled outputs.
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Affiliation(s)
| | | | - David E. Somers
- Department of Molecular Genetics, The Ohio State University; Columbus, OH 43210, USA; (J.Y.); (Y.J.K.)
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14
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Cascant-Lopez E, Crosthwaite SK, Johnson LJ, Harrison RJ. No Evidence That Homologs of Key Circadian Clock Genes Direct Circadian Programs of Development or mRNA Abundance in Verticillium dahliae. Front Microbiol 2020; 11:1977. [PMID: 33013740 PMCID: PMC7493669 DOI: 10.3389/fmicb.2020.01977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 07/27/2020] [Indexed: 01/24/2023] Open
Abstract
Many organisms harbor circadian clocks that promote their adaptation to the rhythmic environment. While a broad knowledge of the molecular mechanism of circadian clocks has been gained through the fungal model Neurospora crassa, little is known about circadian clocks in other fungi. N. crassa belongs to the same class as many important plant pathogens including the vascular wilt fungus Verticillium dahliae. We identified homologs of N. crassa clock proteins in V. dahliae, which showed high conservation in key protein domains. However, no evidence for an endogenous, free-running and entrainable rhythm was observed in the daily formation of conidia and microsclerotia. In N. crassa the frequency (frq) gene encodes a central clock protein expressed rhythmically and in response to light. In contrast, expression of Vdfrq is not light-regulated. Temporal gene expression profiling over 48 h in constant darkness and temperature revealed no circadian expression of key clock genes. Furthermore, RNA-seq over a 24 h time-course revealed no robust oscillations of clock-associated transcripts in constant darkness. Comparison of gene expression between wild-type V. dahliae and a ΔVdfrq mutant showed that genes involved in metabolism, transport and redox processes are mis-regulated in the absence of Vdfrq. In addition, VdΔfrq mutants display growth defects and reduced pathogenicity in a strain dependent manner. Our data indicate that if a circadian clock exists in Verticillium, it is based on alternative mechanisms such as post-transcriptional interactions of VdFRQ and the WC proteins or the components of a FRQ-less oscillator. Alternatively, it could be that whilst the original functions of the clock proteins have been maintained, in this species the interactions that generate robust rhythmicity have been lost or are only triggered when specific environmental conditions are met. The presence of conserved clock genes in genomes should not be taken as definitive evidence of circadian function.
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Affiliation(s)
| | | | - Louise J Johnson
- The School of Biological Sciences, University of Reading, Reading, United Kingdom
| | - Richard J Harrison
- Genetics, Genomics and Breeding, NIAB EMR, East Malling, United Kingdom.,National Institute of Agricultural Botany (NIAB), Cambridge, United Kingdom
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15
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Mieda M. The central circadian clock of the suprachiasmatic nucleus as an ensemble of multiple oscillatory neurons. Neurosci Res 2020; 156:24-31. [DOI: 10.1016/j.neures.2019.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 08/09/2019] [Indexed: 10/26/2022]
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16
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Pilorz V, Astiz M, Heinen KO, Rawashdeh O, Oster H. The Concept of Coupling in the Mammalian Circadian Clock Network. J Mol Biol 2020; 432:3618-3638. [PMID: 31926953 DOI: 10.1016/j.jmb.2019.12.037] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/22/2019] [Accepted: 12/23/2019] [Indexed: 12/13/2022]
Abstract
The circadian clock network regulates daily rhythms in mammalian physiology and behavior to optimally adapt the organism to the 24-h day/night cycle. A central pacemaker, the hypothalamic suprachiasmatic nucleus (SCN), coordinates subordinate cellular oscillators in the brain, as well as in peripheral organs to align with each other and external time. Stability and coordination of this vast network of cellular oscillators is achieved through different levels of coupling. Although coupling at the molecular level and across the SCN is well established and believed to define its function as pacemaker structure, the notion of coupling in other tissues and across the whole system is less well understood. In this review, we describe the different levels of coupling in the mammalian circadian clock system - from molecules to the whole organism. We highlight recent advances in gaining knowledge of the complex organization and function of circadian network regulation and its significance for the generation of stable but plastic intrinsic 24-h rhythms.
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Affiliation(s)
- Violetta Pilorz
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Mariana Astiz
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Keno Ole Heinen
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Oliver Rawashdeh
- The University of Queensland, School of Biomedical Sciences, Faculty of Medicine, St Lucia Qld, 4071, Australia
| | - Henrik Oster
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany.
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17
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Zheleva A, Gómez-Orte E, Sáenz-Narciso B, Ezcurra B, Kassahun H, de Toro M, Miranda-Vizuete A, Schnabel R, Nilsen H, Cabello J. Reduction of mRNA export unmasks different tissue sensitivities to low mRNA levels during Caenorhabditis elegans development. PLoS Genet 2019; 15:e1008338. [PMID: 31525188 PMCID: PMC6762213 DOI: 10.1371/journal.pgen.1008338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 09/26/2019] [Accepted: 07/31/2019] [Indexed: 12/25/2022] Open
Abstract
Animal development requires the execution of specific transcriptional programs in different sets of cells to build tissues and functional organs. Transcripts are exported from the nucleus to the cytoplasm where they are translated into proteins that, ultimately, carry out the cellular functions. Here we show that in Caenorhabditis elegans, reduction of mRNA export strongly affects epithelial morphogenesis and germline proliferation while other tissues remain relatively unaffected. Epithelialization and gamete formation demand a large number of transcripts in the cytoplasm for the duration of these processes. In addition, our findings highlight the existence of a regulatory feedback mechanism that activates gene expression in response to low levels of cytoplasmic mRNA. We expand the genetic characterization of nuclear export factor NXF-1 to other members of the mRNA export pathway to model mRNA export and recycling of NXF-1 back to the nucleus. Our model explains how mutations in genes involved in general processes, such as mRNA export, may result in tissue-specific developmental phenotypes.
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Affiliation(s)
- Angelina Zheleva
- CIBIR (Center for Biomedical Research of La Rioja), Logroño, La Rioja, Spain
| | - Eva Gómez-Orte
- CIBIR (Center for Biomedical Research of La Rioja), Logroño, La Rioja, Spain
| | | | - Begoña Ezcurra
- CIBIR (Center for Biomedical Research of La Rioja), Logroño, La Rioja, Spain
| | - Henok Kassahun
- Department of Clinical Molecular Biology, Institute of Clinical Medicine, University of Oslo and Akershus University Hospital, Lørenskog, Norway
| | - María de Toro
- CIBIR (Center for Biomedical Research of La Rioja), Logroño, La Rioja, Spain
| | - Antonio Miranda-Vizuete
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Ralf Schnabel
- Institute of Genetics, Technische Universität Braunschweig, Germany
| | - Hilde Nilsen
- Department of Clinical Molecular Biology, Institute of Clinical Medicine, University of Oslo and Akershus University Hospital, Lørenskog, Norway
| | - Juan Cabello
- CIBIR (Center for Biomedical Research of La Rioja), Logroño, La Rioja, Spain
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18
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Doi M, Shimatani H, Atobe Y, Murai I, Hayashi H, Takahashi Y, Fustin JM, Yamaguchi Y, Kiyonari H, Koike N, Yagita K, Lee C, Abe M, Sakimura K, Okamura H. Non-coding cis-element of Period2 is essential for maintaining organismal circadian behaviour and body temperature rhythmicity. Nat Commun 2019; 10:2563. [PMID: 31189882 PMCID: PMC6561950 DOI: 10.1038/s41467-019-10532-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 05/16/2019] [Indexed: 12/22/2022] Open
Abstract
Non-coding cis-regulatory elements are essential determinants of development, but their exact impacts on behavior and physiology in adults remain elusive. Cis-element-based transcriptional regulation is believed to be crucial for generating circadian rhythms in behavior and physiology. However, genetic evidence supporting this model is based on mutations in the protein-coding sequences of clock genes. Here, we report generation of mutant mice carrying a mutation only at the E'-box cis-element in the promoter region of the core clock gene Per2. The Per2 E'-box mutation abolishes sustainable molecular clock oscillations and renders circadian locomotor activity and body temperature rhythms unstable. Without the E'-box, Per2 messenger RNA and protein expression remain at mid-to-high levels. Our work delineates the Per2 E'-box as a critical nodal element for keeping sustainable cell-autonomous circadian oscillation and reveals the extent of the impact of the non-coding cis-element in daily maintenance of animal locomotor activity and body temperature rhythmicity.
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Affiliation(s)
- Masao Doi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan.
| | - Hiroyuki Shimatani
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Yuta Atobe
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Iori Murai
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan.,Laboratory of Molecular Brain Science, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Hida Hayashi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Yukari Takahashi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Jean-Michel Fustin
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Yoshiaki Yamaguchi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Hiroshi Kiyonari
- Laboratories for Animal Resource Development and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, 650-0047, Japan
| | - Nobuya Koike
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Kazuhiro Yagita
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Choogon Lee
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Hitoshi Okamura
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan. .,Laboratory of Molecular Brain Science, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan.
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19
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Hastings MH, Maywood ES, Brancaccio M. The Mammalian Circadian Timing System and the Suprachiasmatic Nucleus as Its Pacemaker. BIOLOGY 2019; 8:E13. [PMID: 30862123 PMCID: PMC6466121 DOI: 10.3390/biology8010013] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 11/16/2022]
Abstract
The past twenty years have witnessed the most remarkable breakthroughs in our understanding of the molecular and cellular mechanisms that underpin circadian (approximately one day) time-keeping. Across model organisms in diverse taxa: cyanobacteria (Synechococcus), fungi (Neurospora), higher plants (Arabidopsis), insects (Drosophila) and mammals (mouse and humans), a common mechanistic motif of delayed negative feedback has emerged as the Deus ex machina for the cellular definition of ca. 24 h cycles. This review will consider, briefly, comparative circadian clock biology and will then focus on the mammalian circadian system, considering its molecular genetic basis, the properties of the suprachiasmatic nucleus (SCN) as the principal circadian clock in mammals and its role in synchronising a distributed peripheral circadian clock network. Finally, it will consider new directions in analysing the cell-autonomous and circuit-level SCN clockwork and will highlight the surprising discovery of a central role for SCN astrocytes as well as SCN neurons in controlling circadian behaviour.
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Affiliation(s)
- Michael H Hastings
- MRC Laboratory of Molecular Biology, Division of Neurobiology, CB2 0QH Cambridge, UK.
| | - Elizabeth S Maywood
- MRC Laboratory of Molecular Biology, Division of Neurobiology, CB2 0QH Cambridge, UK.
| | - Marco Brancaccio
- UK Dementia Research Institute at Imperial College London, Division of Brain Sciences, Department of Medicine, W12 0NN London, UK.
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20
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Abstract
The hypothalamus is the brain region responsible for the maintenance of energetic homeostasis. The regulation of this process arises from the ability of the hypothalamus to orchestrate complex physiological responses such as food intake and energy expenditure, circadian rhythm, stress response, and fertility. Metabolic alterations such as obesity can compromise these hypothalamic regulatory functions. Alterations in circadian rhythm, stress response, and fertility further contribute to aggravate the metabolic dysfunction of obesity and contribute to the development of chronic disorders such as depression and infertility.At cellular level, obesity caused by overnutrition can damage the hypothalamus promoting inflammation and impairing hypothalamic neurogenesis. Furthermore, hypothalamic neurons suffer apoptosis and impairment in synaptic plasticity that can compromise the proper functioning of the hypothalamus. Several factors contribute to these phenomena such as ER stress, oxidative stress, and impairments in autophagy. All these observations occur at the same time and it is still difficult to discern whether inflammatory processes are the main drivers of these cellular dysfunctions or if the hypothalamic hormone resistance (insulin, leptin, and ghrelin) can be pinpointed as the source of several of these events.Understanding the mechanisms that underlie the pathophysiology of obesity in the hypothalamus is crucial for the development of strategies that can prevent or attenuate the deleterious effects of obesity.
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21
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Hasan S, Foster RG, Vyazovskiy VV, Peirson SN. Effects of circadian misalignment on sleep in mice. Sci Rep 2018; 8:15343. [PMID: 30367119 PMCID: PMC6203841 DOI: 10.1038/s41598-018-33480-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 09/19/2018] [Indexed: 11/18/2022] Open
Abstract
Circadian rhythms and sleep-wake history determine sleep duration and intensity, and influence subsequent waking. Previous studies have shown that T cycles - light-dark (LD) cycles differing from 24 h - lead to acute changes in the daily amount and distribution of waking and sleep. However, little is known about the long-term effects of T cycles. Here we performed continuous 10 day recording of electroencephalography (EEG), locomotor activity and core body temperature in C57BL/6 mice under a T20 cycle, to investigate spontaneous sleep and waking at baseline compared with when the circadian clock was misaligned and then re-aligned with respect to the external LD cycle. We found that the rhythmic distribution of sleep was abolished during misalignment, while the time course of EEG slow wave activity (1–4 Hz) was inverted compared to baseline. Although the typical light-dark distribution of NREM sleep was re-instated when animals were re-aligned, slow wave activity during NREM sleep showed an atypical increase in the dark phase, suggesting a long-term effect of T cycles on sleep intensity. Our data show that circadian misalignment results in previously uncharacterised long-term effects on sleep, which may have important consequences for behaviour.
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Affiliation(s)
- Sibah Hasan
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, OX13RE, United Kingdom
| | - Russell G Foster
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, OX13RE, United Kingdom
| | - Vladyslav V Vyazovskiy
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, United Kingdom.
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, OX13RE, United Kingdom.
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22
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Wong DCS, O’Neill JS. Non-transcriptional processes in circadian rhythm generation. CURRENT OPINION IN PHYSIOLOGY 2018; 5:117-132. [PMID: 30596188 PMCID: PMC6302373 DOI: 10.1016/j.cophys.2018.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
'Biological clocks' orchestrate mammalian biology to a daily rhythm. Whilst 'clock gene' transcriptional circuits impart rhythmic regulation to myriad cellular systems, our picture of the biochemical mechanisms that determine their circadian (∼24 hour) period is incomplete. Here we consider the evidence supporting different models for circadian rhythm generation in mammalian cells in light of evolutionary factors. We find it plausible that the circadian timekeeping mechanism in mammalian cells is primarily protein-based, signalling biological timing information to the nucleus by the post-translational regulation of transcription factor activity, with transcriptional feedback imparting robustness to the oscillation via hysteresis. We conclude by suggesting experiments that might distinguish this model from competing paradigms.
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23
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Barbiero S, Aimo A, Castiglione V, Giannoni A, Vergaro G, Passino C, Emdin M. Healthy hearts at hectic pace: From daily life stress to abnormal cardiomyocyte function and arrhythmias. Eur J Prev Cardiol 2018; 25:1419-1430. [PMID: 30052067 DOI: 10.1177/2047487318790614] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The hectic pace of contemporary life is a major source of acute and chronic stress, which may have a deleterious impact on body health . In the field of cardiovascular disease, acute emotional stress has been associated with coronary spasm and Takotsubo cardiomyopathy, whereas the manifestations of chronic stress have been overlooked, and most underlying pathophysiology remains to be elucidated. Chronic stress affects the neuronal circuitry composed of cortico-limbic structures and the nuclei regulating autonomic function, eliciting a sympatho-vagal imbalance, characterised by adrenergic activation and vagal withdrawal. Sympathetic terminals are connected to cardiomyocytes in a quasi-synaptic way, producing the so called 'neuro-cardiac junction'. During chronic stress, norepinephrine release is increased, leading to overstimulation of cardiomyocytes via β1-adrenergic receptors, influencing mainly calcium dynamics, and β2-adrenergic receptors, which control housekeeping functions. The circadian rhythm of cardiomyocytes is then impaired, with elongation of the catabolic ('light' phase) over the anabolic ('nocturnal') phase. This leads to a depletion of cell energy storage, and a decreased turnover of cell constituents. Even cell interactions are affected, as coupling between cardiomyocytes decreases while coupling between cardiomyocytes and fibroblasts increases. The ultimate results are changes in the shape and velocity of action potential, fibroblast activation and deposition of extracellular matrix. These alterations may predispose to arrhythmias and may favour the development of a stress-related cardiomyopathy. A better comprehension of this cascade of events may allow us to identify screening protocols and treatment strategies (meditation, yoga, physical activity, psychological assistance, β-blockers) to prevent or relieve ongoing cardiac damage.
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Affiliation(s)
- Silvia Barbiero
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy
| | - Alberto Aimo
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,2 Cardiology Division, University Hospital of Pisa, Italy
| | | | - Alberto Giannoni
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,3 Cardiology Division, Fondazione Toscana Gabriele Monasterio, Italy
| | - Giuseppe Vergaro
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,3 Cardiology Division, Fondazione Toscana Gabriele Monasterio, Italy
| | - Claudio Passino
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,3 Cardiology Division, Fondazione Toscana Gabriele Monasterio, Italy
| | - Michele Emdin
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,3 Cardiology Division, Fondazione Toscana Gabriele Monasterio, Italy
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24
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Clocking In Time to Gate Memory Processes: The Circadian Clock Is Part of the Ins and Outs of Memory. Neural Plast 2018; 2018:6238989. [PMID: 29849561 PMCID: PMC5925033 DOI: 10.1155/2018/6238989] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 01/22/2018] [Accepted: 02/05/2018] [Indexed: 01/11/2023] Open
Abstract
Learning, memory consolidation, and retrieval are processes known to be modulated by the circadian (circa: about; dies: day) system. The circadian regulation of memory performance is evolutionarily conserved, independent of the type and complexity of the learning paradigm tested, and not specific to crepuscular, nocturnal, or diurnal organisms. In mammals, long-term memory (LTM) formation is tightly coupled to de novo gene expression of plasticity-related proteins and posttranslational modifications and relies on intact cAMP/protein kinase A (PKA)/protein kinase C (PKC)/mitogen-activated protein kinase (MAPK)/cyclic adenosine monophosphate response element-binding protein (CREB) signaling. These memory-essential signaling components cycle rhythmically in the hippocampus across the day and night and are clearly molded by an intricate interplay between the circadian system and memory. Important components of the circadian timing mechanism and its plasticity are members of the Period clock gene family (Per1, Per2). Interestingly, Per1 is rhythmically expressed in mouse hippocampus. Observations suggest important and largely unexplored roles of the clock gene protein PER1 in synaptic plasticity and in the daytime-dependent modulation of learning and memory. Here, we review the latest findings on the role of the clock gene Period 1 (Per1) as a candidate molecular and mechanistic blueprint for gating the daytime dependency of memory processing.
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25
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Chao HW, Doi M, Fustin JM, Chen H, Murase K, Maeda Y, Hayashi H, Tanaka R, Sugawa M, Mizukuchi N, Yamaguchi Y, Yasunaga JI, Matsuoka M, Sakai M, Matsumoto M, Hamada S, Okamura H. Circadian clock regulates hepatic polyploidy by modulating Mkp1-Erk1/2 signaling pathway. Nat Commun 2017; 8:2238. [PMID: 29269828 PMCID: PMC5740157 DOI: 10.1038/s41467-017-02207-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/13/2017] [Indexed: 01/08/2023] Open
Abstract
Liver metabolism undergoes robust circadian oscillations in gene expression and enzymatic activity essential for liver homeostasis, but whether the circadian clock controls homeostatic self-renewal of hepatocytes is unknown. Here we show that hepatocyte polyploidization is markedly accelerated around the central vein, the site of permanent cell self-renewal, in mice deficient in circadian Period genes. In these mice, a massive accumulation of hyperpolyploid mononuclear and binuclear hepatocytes occurs due to impaired mitogen-activated protein kinase phosphatase 1 (Mkp1)-mediated circadian modulation of the extracellular signal-regulated kinase (Erk1/2) activity. Time-lapse imaging of hepatocytes suggests that the reduced activity of Erk1/2 in the midbody during cytokinesis results in abscission failure, leading to polyploidization. Manipulation of Mkp1 phosphatase activity is sufficient to change the ploidy level of hepatocytes. These data provide clear evidence that the Period genes not only orchestrate dynamic changes in metabolic activity, but also regulate homeostatic self-renewal of hepatocytes through Mkp1-Erk1/2 signaling pathway. Circadian clock regulates hepatic gene expression and functions. Here Chao et al. show that alteration of circadian clock genes by Period deletion induces polyploidy in hepatocytes due to impaired regulation of Erk signaling by mitogen-activated protein kinase phosphatase 1.
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Affiliation(s)
- Hsu-Wen Chao
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan.,Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 11031, Taiwan
| | - Masao Doi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Jean-Michel Fustin
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Huatao Chen
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Kimihiko Murase
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan.,The Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Yuki Maeda
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Hida Hayashi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Rina Tanaka
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Maho Sugawa
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Naoki Mizukuchi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Yoshiaki Yamaguchi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Jun-Ichirou Yasunaga
- Laboratory of Virus Control, Institute for Virus Research, Kyoto University, Kyoto, 606-8507, Japan
| | - Masao Matsuoka
- Laboratory of Virus Control, Institute for Virus Research, Kyoto University, Kyoto, 606-8507, Japan.,Department of Hematology, Rheumatology, and Infectious Diseases, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan
| | - Mashito Sakai
- Department of Molecular Metabolic Regulation, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, 162-8655, Japan
| | - Michihiro Matsumoto
- Department of Molecular Metabolic Regulation, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, 162-8655, Japan
| | | | - Hitoshi Okamura
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan.
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26
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Stevenson TJ. Epigenetic Regulation of Biological Rhythms: An Evolutionary Ancient Molecular Timer. Trends Genet 2017; 34:90-100. [PMID: 29221677 DOI: 10.1016/j.tig.2017.11.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 11/09/2017] [Accepted: 11/15/2017] [Indexed: 01/12/2023]
Abstract
Biological rhythms are pervasive in nature, yet our understanding of the molecular mechanisms that govern timing is far from complete. The rapidly emerging research focus on epigenetic plasticity has revealed a system that is highly dynamic and reversible. In this Opinion, I propose an epigenetic clock model that outlines how molecular modifications, such as DNA methylation, are integral components for timing endogenous biological rhythms. The hypothesis proposed is that an epigenetic clock serves to maintain the period of molecular rhythms via control over the phase of gene transcription and this timing mechanism resides in all cells, from unicellular to complex organisms. The model also provides a novel framework for the timing of epigenetic modifications during the lifespan and transgenerational inheritance of an organism.
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Affiliation(s)
- Tyler J Stevenson
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK.
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27
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Weger M, Diotel N, Dorsemans AC, Dickmeis T, Weger BD. Stem cells and the circadian clock. Dev Biol 2017; 431:111-123. [DOI: 10.1016/j.ydbio.2017.09.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/11/2017] [Accepted: 09/08/2017] [Indexed: 12/20/2022]
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28
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Ono D, Honma S, Nakajima Y, Kuroda S, Enoki R, Honma KI. Dissociation of Per1 and Bmal1 circadian rhythms in the suprachiasmatic nucleus in parallel with behavioral outputs. Proc Natl Acad Sci U S A 2017; 114:E3699-E3708. [PMID: 28416676 PMCID: PMC5422828 DOI: 10.1073/pnas.1613374114] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The temporal order of physiology and behavior in mammals is primarily regulated by the circadian pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). Taking advantage of bioluminescence reporters, we monitored the circadian rhythms of the expression of clock genes Per1 and Bmal1 in the SCN of freely moving mice and found that the rate of phase shifts induced by a single light pulse was different in the two rhythms. The Per1-luc rhythm was phase-delayed instantaneously by the light presented at the subjective evening in parallel with the activity onset of behavioral rhythm, whereas the Bmal1-ELuc rhythm was phase-delayed gradually, similar to the activity offset. The dissociation was confirmed in cultured SCN slices of mice carrying both Per1-luc and Bmal1-ELuc reporters. The two rhythms in a single SCN slice showed significantly different periods in a long-term (3 wk) culture and were internally desynchronized. Regional specificity in the SCN was not detected for the period of Per1-luc and Bmal1-ELuc rhythms. Furthermore, neither is synchronized with circadian intracellular Ca2+ rhythms monitored by a calcium indicator, GCaMP6s, or with firing rhythms monitored on a multielectrode array dish, although the coupling between the circadian firing and Ca2+ rhythms persisted during culture. These findings indicate that the expressions of two key clock genes, Per1 and Bmal1, in the SCN are regulated in such a way that they may adopt different phases and free-running periods relative to each other and are respectively associated with the expression of activity onset and offset.
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Affiliation(s)
- Daisuke Ono
- Photonic Bioimaging Section, Research Center for Cooperative Projects, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan;
| | - Sato Honma
- Department of Chronomedicine, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan;
| | - Yoshihiro Nakajima
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Kagawa 761-0395, Japan
| | - Shigeru Kuroda
- Research Institute for Electronic Science, Hokkaido University, Sapporo, 001-0020, Japan
| | - Ryosuke Enoki
- Photonic Bioimaging Section, Research Center for Cooperative Projects, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan
- Department of Chronomedicine, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan
| | - Ken-Ichi Honma
- Department of Chronomedicine, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan
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29
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Jones MA. Interplay of Circadian Rhythms and Light in the Regulation of Photosynthesis-Derived Metabolism. PROGRESS IN BOTANY VOL. 79 2017:147-171. [PMID: 0 DOI: 10.1007/124_2017_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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30
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Gizowski C, Zaelzer C, Bourque CW. Clock-driven vasopressin neurotransmission mediates anticipatory thirst prior to sleep. Nature 2016; 537:685-8. [DOI: 10.1038/nature19756] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 08/15/2016] [Indexed: 11/09/2022]
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31
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Feeney KA, Hansen LL, Putker M, Olivares-Yañez C, Day J, Eades LJ, Larrondo LF, Hoyle NP, O'Neill JS, van Ooijen G. Daily magnesium fluxes regulate cellular timekeeping and energy balance. Nature 2016; 532:375-9. [PMID: 27074515 PMCID: PMC4886825 DOI: 10.1038/nature17407] [Citation(s) in RCA: 169] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/08/2016] [Indexed: 12/15/2022]
Abstract
Circadian clocks are fundamental to the biology of most eukaryotes, coordinating behaviour and physiology to resonate with the environmental cycle of day and night through complex networks of clock-controlled genes. A fundamental knowledge gap exists, however, between circadian gene expression cycles and the biochemical mechanisms that ultimately facilitate circadian regulation of cell biology. Here we report circadian rhythms in the intracellular concentration of magnesium ions, [Mg(2+)]i, which act as a cell-autonomous timekeeping component to determine key clock properties both in a human cell line and in a unicellular alga that diverged from each other more than 1 billion years ago. Given the essential role of Mg(2+) as a cofactor for ATP, a functional consequence of [Mg(2+)]i oscillations is dynamic regulation of cellular energy expenditure over the daily cycle. Mechanistically, we find that these rhythms provide bilateral feedback linking rhythmic metabolism to clock-controlled gene expression. The global regulation of nucleotide triphosphate turnover by intracellular Mg(2+) availability has potential to impact upon many of the cell's more than 600 MgATP-dependent enzymes and every cellular system where MgNTP hydrolysis becomes rate limiting. Indeed, we find that circadian control of translation by mTOR is regulated through [Mg(2+)]i oscillations. It will now be important to identify which additional biological processes are subject to this form of regulation in tissues of multicellular organisms such as plants and humans, in the context of health and disease.
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Affiliation(s)
- Kevin A. Feeney
- MRC Laboratory for Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Louise L. Hansen
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Marrit Putker
- MRC Laboratory for Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Consuelo Olivares-Yañez
- Millennium Nucleus for Fungal Integrative and Synthetic Biology, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
| | - Jason Day
- Department of Earth Sciences, University of Cambridge, Downing St, Cambridge CB2 3EQ, UK
| | - Lorna J. Eades
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Luis F. Larrondo
- Millennium Nucleus for Fungal Integrative and Synthetic Biology, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
| | - Nathaniel P. Hoyle
- MRC Laboratory for Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - John S. O'Neill
- MRC Laboratory for Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Gerben van Ooijen
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
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32
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Rhythmic expression of cryptochrome induces the circadian clock of arrhythmic suprachiasmatic nuclei through arginine vasopressin signaling. Proc Natl Acad Sci U S A 2016; 113:2732-7. [PMID: 26903624 DOI: 10.1073/pnas.1519044113] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Circadian rhythms in mammals are coordinated by the suprachiasmatic nucleus (SCN). SCN neurons define circadian time using transcriptional/posttranslational feedback loops (TTFL) in which expression of Cryptochrome (Cry) and Period (Per) genes is inhibited by their protein products. Loss of Cry1 and Cry2 stops the SCN clock, whereas individual deletions accelerate and decelerate it, respectively. At the circuit level, neuronal interactions synchronize cellular TTFLs, creating a spatiotemporal wave of gene expression across the SCN that is lost in Cry1/2-deficient SCN. To interrogate the properties of CRY proteins required for circadian function, we expressed CRY in SCN of Cry-deficient mice using adeno-associated virus (AAV). Expression of CRY1::EGFP or CRY2::EGFP under a minimal Cry1 promoter was circadian and rapidly induced PER2-dependent bioluminescence rhythms in previously arrhythmic Cry1/2-deficient SCN, with periods appropriate to each isoform. CRY1::EGFP appropriately lengthened the behavioral period in Cry1-deficient mice. Thus, determination of specific circadian periods reflects properties of the respective proteins, independently of their phase of expression. Phase of CRY1::EGFP expression was critical, however, because constitutive or phase-delayed promoters failed to sustain coherent rhythms. At the circuit level, CRY1::EGFP induced the spatiotemporal wave of PER2 expression in Cry1/2-deficient SCN. This was dependent on the neuropeptide arginine vasopressin (AVP) because it was prevented by pharmacological blockade of AVP receptors. Thus, our genetic complementation assay reveals acute, protein-specific induction of cell-autonomous and network-level circadian rhythmicity in SCN never previously exposed to CRY. Specifically, Cry expression must be circadian and appropriately phased to support rhythms, and AVP receptor signaling is required to impose circuit-level circadian function.
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33
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Diurnal Variations of Circulating Extracellular Vesicles Measured by Nano Flow Cytometry. PLoS One 2016; 11:e0144678. [PMID: 26745887 PMCID: PMC4706300 DOI: 10.1371/journal.pone.0144678] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 11/20/2015] [Indexed: 11/25/2022] Open
Abstract
The identification of extracellular vesicles (EVs) as intercellular conveyors of biological information has recently emerged as a novel paradigm in signaling, leading to the exploitation of EVs and their contents as biomarkers of various diseases. However, whether there are diurnal variations in the size, number, and tissue of origin of blood EVs is currently not known, and could have significant implications when using EVs as biomarkers for disease progression. Currently available technologies for the measurement of EV size and number are either time consuming, require specialized equipment, or lack sufficient accuracy across a range of EV sizes. Flow cytometry represents an attractive alternative to these methods; however, traditional flow cytometers are only capable of measuring particles down to 500 nm, which is significantly larger than the average and median sizes of plasma EVs. Utilizing a Beckman Coulter MoFlo XDP flow cytometer with NanoView module, we employed nanoscale flow cytometry (termed nanoFCM) to examine the relative number and scatter distribution of plasma EVs at three different time points during the day in 6 healthy adults. Analysis of liposomes and plasma EVs proved that nanoFCM is capable of detecting biologically-relevant vesicles down to 100 nm in size. With this high resolution configuration, we observed variations in the relative size (FSC/SSC distributions) and concentration (proportions) of EVs in healthy adult plasma across the course of a day, suggesting that there are diurnal variations in the number and size distribution of circulating EV populations. The use of nanoFCM provides a valuable tool for the study of EVs in both health and disease; however, additional refinement of nanoscale flow cytometric methods is needed for use of these instruments for quantitative particle counting and sizing. Furthermore, larger scale studies are necessary to more clearly define the diurnal variations in circulating EVs, and thus further inform their use as biomarkers for disease.
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Putker M, O’Neill JS. Reciprocal Control of the Circadian Clock and Cellular Redox State - a Critical Appraisal. Mol Cells 2016; 39:6-19. [PMID: 26810072 PMCID: PMC4749875 DOI: 10.14348/molcells.2016.2323] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 11/26/2015] [Indexed: 12/16/2022] Open
Abstract
Redox signalling comprises the biology of molecular signal transduction mediated by reactive oxygen (or nitrogen) species. By specific and reversible oxidation of redox-sensitive cysteines, many biological processes sense and respond to signals from the intracellular redox environment. Redox signals are therefore important regulators of cellular homeostasis. Recently, it has become apparent that the cellular redox state oscillates in vivo and in vitro, with a period of about one day (circadian). Circadian time-keeping allows cells and organisms to adapt their biology to resonate with the 24-hour cycle of day/night. The importance of this innate biological time-keeping is illustrated by the association of clock disruption with the early onset of several diseases (e.g. type II diabetes, stroke and several forms of cancer). Circadian regulation of cellular redox balance suggests potentially two distinct roles for redox signalling in relation to the cellular clock: one where it is regulated by the clock, and one where it regulates the clock. Here, we introduce the concepts of redox signalling and cellular timekeeping, and then critically appraise the evidence for the reciprocal regulation between cellular redox state and the circadian clock. We conclude there is a substantial body of evidence supporting circadian regulation of cellular redox state, but that it would be premature to conclude that the converse is also true. We therefore propose some approaches that might yield more insight into redox control of cellular timekeeping.
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Affiliation(s)
- Marrit Putker
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH,
UK
| | - John Stuart O’Neill
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH,
UK
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35
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Rey G, Reddy AB. Interplay between cellular redox oscillations and circadian clocks. Diabetes Obes Metab 2015; 17 Suppl 1:55-64. [PMID: 26332969 DOI: 10.1111/dom.12519] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 05/07/2015] [Indexed: 12/19/2022]
Abstract
The circadian clock is a cellular timekeeping mechanism that helps organisms from bacteria to humans to organize their behaviour and physiology around the solar cycle. Current models for circadian timekeeping incorporate transcriptional/translational feedback loop mechanisms in the predominant model systems. However, recent evidence suggests that non-transcriptional oscillations such as metabolic and redox cycles may play a fundamental role in circadian timekeeping. Peroxiredoxins, an antioxidant protein family, undergo rhythmic oxidation on the circadian time scale in a variety of species, including bacteria, insects and mammals, but also in red blood cells, a naturally occurring, non-transcriptional system. The profound interconnectivity between circadian and redox pathways strongly suggests that a conserved timekeeping mechanism based on redox cycles could be integral to generating circadian rhythms.
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Affiliation(s)
- G Rey
- Department of Clinical Neurosciences, University of Cambridge Metabolic Research Laboratories, NIHR Biomedical Research Centre, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - A B Reddy
- Department of Clinical Neurosciences, University of Cambridge Metabolic Research Laboratories, NIHR Biomedical Research Centre, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
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36
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Le Bihan T, Hindle M, Martin SF, Barrios-Llerena ME, Krahmer J, Kis K, Millar AJ, van Ooijen G. Label-free quantitative analysis of the casein kinase 2-responsive phosphoproteome of the marine minimal model species Ostreococcus tauri. Proteomics 2015; 15:4135-44. [PMID: 25930153 PMCID: PMC4716292 DOI: 10.1002/pmic.201500086] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 03/25/2015] [Accepted: 04/24/2015] [Indexed: 11/06/2022]
Abstract
Casein kinase 2 (CK2) is a protein kinase that phosphorylates a plethora of cellular target proteins involved in processes including DNA repair, cell cycle control, and circadian timekeeping. CK2 is functionally conserved across eukaryotes, although the substrate proteins identified in a range of complex tissues are often different. The marine alga Ostreococcus tauri is a unicellular eukaryotic model organism ideally suited to efficiently study generic roles of CK2 in the cellular circadian clock. Overexpression of CK2 leads to a slow circadian rhythm, verifying functional conservation of CK2 in timekeeping. The proteome was analysed in wild-type and CK2-overexpressing algae at dawn and dusk, revealing that differential abundance of the global proteome across the day is largely unaffected by overexpression. However, CK2 activity contributed more strongly to timekeeping at dusk than at dawn. The phosphoproteome of a CK2 overexpression line and cells treated with CK2 inhibitor was therefore analysed and compared to control cells at dusk. We report an extensive catalogue of 447 unique CK2-responsive differential phosphopeptide motifs to inform future studies into CK2 activity in the circadian clock of more complex tissues. All MS data have been deposited in the ProteomeXchange with identifier PXD000975 (http://proteomecentral.proteomexchange.org/dataset/PXD000975).
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Affiliation(s)
- Thierry Le Bihan
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Matthew Hindle
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Sarah F Martin
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | | | - Johanna Krahmer
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Katalin Kis
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Andrew J Millar
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Gerben van Ooijen
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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Metabolic Cycles in Yeast Share Features Conserved among Circadian Rhythms. Curr Biol 2015; 25:1056-62. [PMID: 25866393 PMCID: PMC4406945 DOI: 10.1016/j.cub.2015.02.035] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 12/17/2014] [Accepted: 02/09/2015] [Indexed: 01/22/2023]
Abstract
Cell-autonomous circadian rhythms allow organisms to temporally orchestrate their internal state to anticipate and/or resonate with the external environment [1, 2]. Although ∼24-hr periodicity is observed across aerobic eukaryotes, the central mechanism has been hard to dissect because few simple models exist, and known clock proteins are not conserved across phylogenetic kingdoms [1, 3, 4]. In contrast, contributions to circadian rhythmicity made by a handful of post-translational mechanisms, such as phosphorylation of clock proteins by casein kinase 1 (CK1) and glycogen synthase kinase 3 (GSK3), appear conserved among phyla [3, 5]. These kinases have many other essential cellular functions and are better conserved in their contribution to timekeeping than any of the clock proteins they phosphorylate [6]. Rhythmic oscillations in cellular redox state are another universal feature of circadian timekeeping, e.g., over-oxidation cycles of abundant peroxiredoxin proteins [7–9]. Here, we use comparative chronobiology to distinguish fundamental clock mechanisms from species and/or tissue-specific adaptations and thereby identify features shared between circadian rhythms in mammalian cells and non-circadian temperature-compensated respiratory oscillations in budding yeast [10]. We find that both types of oscillations are coupled with the cell division cycle, exhibit period determination by CK1 and GSK3, and have peroxiredoxin over-oxidation cycles. We also explore how peroxiredoxins contribute to YROs. Our data point to common mechanisms underlying both YROs and circadian rhythms and suggest two interpretations: either certain biochemical systems are simply permissive for cellular oscillations (with frequencies from hours to days) or this commonality arose via divergence from an ancestral cellular clock. Yeast respiratory oscillations (YROs) share features with circadian rhythms Changes that alter the period of circadian rhythms have the same effect on YROs Oxidation cycles of peroxiredoxins are a characteristic of both oscillations Mechanistic similarities between these cycles may reflect a common origin
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38
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Role for Protein Kinase A in the Neurospora Circadian Clock by Regulating White Collar-Independent frequency Transcription through Phosphorylation of RCM-1. Mol Cell Biol 2015; 35:2088-102. [PMID: 25848091 DOI: 10.1128/mcb.00709-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 03/30/2015] [Indexed: 01/24/2023] Open
Abstract
Rhythmic activation and repression of clock gene expression is essential for the eukaryotic circadian clock functions. In the Neurospora circadian oscillator, the transcription of the frequency (frq) gene is periodically activated by the White Collar (WC) complex and suppressed by the FRQ-FRH complex. We previously showed that there is WC-independent frq transcription and its repression is required for circadian gene expression. How WC-independent frq transcription is regulated is not known. We show here that elevated protein kinase A (PKA) activity results in WC-independent frq transcription and the loss of clock function. We identified RCM-1 as the protein partner of RCO-1 and an essential component of the clock through its role in suppressing WC-independent frq transcription. RCM-1 is a phosphoprotein and is a substrate of PKA in vivo and in vitro. Mutation of the PKA-dependent phosphorylation sites on RCM-1 results in WC-independent transcription of frq and impaired clock function. Furthermore, we showed that RCM-1 is associated with the chromatin at the frq locus, a process that is inhibited by PKA. Together, our results demonstrate that PKA regulates frq transcription by inhibiting RCM-1 activity through RCM-1 phosphorylation.
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39
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Hoyle NP, O'Neill JS. Oxidation-reduction cycles of peroxiredoxin proteins and nontranscriptional aspects of timekeeping. Biochemistry 2014; 54:184-93. [PMID: 25454580 PMCID: PMC4302831 DOI: 10.1021/bi5008386] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The circadian clock allows organisms to accurately predict the earth's rotation and modify their behavior as a result. Genetic analyses in a variety of organisms have defined a mechanism based largely on gene expression feedback loops. However, as we delve more deeply into the mechanisms of circadian timekeeping, we are discovering that post-translational mechanisms play a key role in defining the character of the clock. We are also discovering that these modifications are inextricably linked to cellular metabolism, including redox homeostasis. A robust circadian oscillation in the redox status of the peroxiredoxins (a major class of cellular antioxidants) was recently shown to be remarkably conserved from archaea and cyanobacteria all the way to plants and animals. Furthermore, recent findings indicate that cellular redox status is coupled not only to canonical circadian gene expression pathways but also to a noncanonical transcript-independent circadian clock. The redox rhythms observed in peroxiredoxins in the absence of canonical clock mechanisms may hint at the nature of this new and hitherto unknown aspect of circadian timekeeping.
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Affiliation(s)
- Nathaniel P Hoyle
- Laboratory of Molecular Biology, Medical Research Council , Francis Crick Avenue, Cambridge CB2 0QH, U.K
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40
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Maywood ES, Chesham JE, Smyllie NJ, Hastings MH. The Tau mutation of casein kinase 1ε sets the period of the mammalian pacemaker via regulation of Period1 or Period2 clock proteins. J Biol Rhythms 2014; 29:110-8. [PMID: 24682205 PMCID: PMC4131702 DOI: 10.1177/0748730414520663] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The suprachiasmatic nucleus (SCN) of the hypothalamus is the principal circadian pacemaker in mammals, coordinating daily metabolic and physiological rhythms with the cycle of sleep and wakefulness. SCN neurons define circadian time via an auto-regulatory feedback loop in which the activation of Period (Per) and Cryptochrome genes is periodically suppressed by their own protein products. Casein kinase 1 (CK1) enzymes have a critical role in circadian pacemaking because they phosphorylate PER proteins and thereby direct their proteasomal degradation. In human pedigrees, individual mutations in either hCK1 or hPER2 lead to advanced sleep phase disorders, whereas in rodents, the Tau mutation of CK1 epsilon (CK1ϵTau) accelerates rest-activity cycles and shortens the period of the SCN molecular pacemaker. Biochemical analyses of recombinant PER proteins in cultured cells and endogenous proteins in peripheral tissues have identified PER1 and PER2, but not PER3, as direct substrates of CK1ϵ. The purpose of this study, therefore, was to determine the relative contributions of endogenous PER proteins to the period-accelerating effects of CK1ϵTau, both in vivo and in vitro. CK1ϵTau mice were mated onto Per1-, Per2-, and Per1-Per2 (Per1/2) double-null backgrounds, in all cases carrying the Per1-luciferase bioluminescent circadian reporter gene. Mice lacking both PER1 and PER2 were behaviorally arrhythmic, confirming the inadequacy of PER3 as a circadian factor. Individual loss of either PER1 or PER2 had no significant effect on the circadian period or quality of wheel-running behavior, and CK1ϵTau accelerated behavioral rhythms in both Per1- and Per2-null mice. CK1ϵTau also accelerated in vitro molecular pacemaking in SCN lacking either PER1 or PER2, with a greater effect in PER2-dependent (i.e., Per1-null) SCN than in PER1-dependent slices. In double-null slices, some SCN were arrhythmic, whereas others exhibited transient rhythms, which trended nonsignificantly toward a shorter period. Both short-period and long-period rhythms could be identified in individual SCN neurons imaged by charge-coupled device camera. CK1ϵTau had no effect, however, on SCN-level or individual neuronal rhythms in the absence of PER1 and PER2. Thus, the CK1ϵTau allele has divergent actions, acting via both endogenous PER1 and PER2, but not PER3 protein, to mediate its circadian actions in vivo. Moreover, PER-independent cellular oscillations may contribute to pacemaking, but they are unstable and imprecise, and are not affected by the Tau mutation.
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Affiliation(s)
- E S Maywood
- MRC Laboratory of Molecular Biology, Cambridge, UK
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Narishige S, Kuwahara M, Shinozaki A, Okada S, Ikeda Y, Kamagata M, Tahara Y, Shibata S. Effects of caffeine on circadian phase, amplitude and period evaluated in cells in vitro and peripheral organs in vivo in PER2::LUCIFERASE mice. Br J Pharmacol 2014; 171:5858-69. [PMID: 25160990 DOI: 10.1111/bph.12890] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 06/27/2014] [Accepted: 08/16/2014] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND AND PURPOSE Caffeine is one of the most commonly used psychoactive substances. Circadian rhythms consist of the main suprachiasmatic nucleus (SCN) clocks and peripheral clocks. Although caffeine lengthens circadian rhythms and modifies phase changes in SCN-operated rhythms, the effects on caffeine on the phase, period and amplitude of peripheral organ clocks are not known. In addition, the role of cAMP/Ca(2+) signalling in effects of caffeine on rhythm has not been fully elucidated. EXPERIMENTAL APPROACH We examined whether chronic or transient application of caffeine affects circadian period/amplitude and phase by evaluating bioluminescence rhythm in PER2::LUCIFERASE knock-in mice. Circadian rhythms were monitored in vitro using fibroblasts and ex vivo and in vivo for monitoring of peripheral clocks. KEY RESULTS Chronic application of caffeine (0.1-10 mM) increased period and amplitude in vitro. Transient application of caffeine (10 mM) near the bottom of the decreasing phase of bioluminescence rhythm caused phase advance in vitro. Caffeine (0.1%) intake caused a phase delay under light-dark or constant dark conditions, suggesting a period-lengthening effect in vivo. Caffeine (20 mg·kg(-1) ) at daytime or at late night-time caused phase advance or delay in bioluminescence rhythm in the liver and kidney respectively. The complicated roles of cAMP/Ca(2+) signalling may be involved in the caffeine-induced increase of period and amplitude in vitro. CONCLUSIONS AND IMPLICATIONS Caffeine affects circadian rhythm in mice by lengthening the period and causing a phase shift of peripheral clocks. These results suggest that caffeine intake with food/drink may help with food-induced resetting of peripheral circadian clocks.
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Affiliation(s)
- Seira Narishige
- Laboratory of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo, Japan
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Temporal behaviour profiles of Mus musculus in nature are affected by population activity. Physiol Behav 2014; 139:351-60. [PMID: 25446229 DOI: 10.1016/j.physbeh.2014.11.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 11/04/2014] [Accepted: 11/05/2014] [Indexed: 01/28/2023]
Abstract
Animals have circadian clocks that govern their activity pattern, resulting in 24h rhythms in physiology and behaviour. Under laboratory conditions, light is the major external signal that affects temporal patterns in behaviour, and Mus musculus is strictly nocturnal in its behaviour. In the present study we questioned whether under natural conditions, environmental factors other than light affect the temporal profile of mice. In order to test this, we investigated the activity patterns of free-ranging M. musculus in a natural habitat, using sensors and a camera integrated into a recording unit that the mice could freely enter and leave. Our data show that mice have seasonal fluctuations in activity duration (6.7±0.82 h in summer, 11.3±1.80 h in winter). Furthermore, although primarily nocturnal, wild mice also exhibit daytime activity from spring until late autumn. A multivariate analysis revealed that the major factor correlating with increased daytime activity was population activity, defined as the number of visits to the recording site. Day length had a small but significant effect. Further analysis revealed that the relative population activity (compared to the past couple of days) is a better predictor of daytime activity than absolute population activity. Light intensity and temperature did not have a significant effect on daytime activity. The amount of variance explained by external factors is 51.9%, leaving surprisingly little unexplained variance that might be attributed to the internal clock. Our data further indicate that mice determine population activity by comparing a given night with the preceding 2-7 nights, a time frame suggesting a role for olfactory cues. We conclude that relative population activity is a major factor controlling the temporal activity patterns of M. musculus in an unrestricted natural population.
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Bmal1 is an essential regulator for circadian cytosolic Ca²⁺ rhythms in suprachiasmatic nucleus neurons. J Neurosci 2014; 34:12029-38. [PMID: 25186748 DOI: 10.1523/jneurosci.5158-13.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The hypothalamic suprachiasmatic nucleus (SCN) plays a pivotal role in the mammalian circadian clock system. Bmal1 is a clock gene that drives transcriptional-translational feedback loops (TTFLs) for itself and other genes, and is expressed in nearly all SCN neurons. Despite strong evidence that Bmal1-null mutant mice display arrhythmic behavior under constant darkness, the function of Bmal1 in neuronal activity is unknown. Recently, periodic changes in the levels of intracellular signaling messengers, such as cytosolic Ca(2+) and cAMP, were suggested to regulate TTFLs. However, the opposite aspect of how clock gene TTFLs regulate cytosolic signaling remains unclear. To investigate intracellular Ca(2+) dynamics under Bmal1 perturbations, we cotransfected some SCN neurons with yellow cameleon together with wild-type or dominant-negative Bmal1 using a gene-gun applied for mouse organotypic cultures. Immunofluorescence staining for a tag protein linked to BMAL1 showed nuclear expression of wild-type BMAL1 and its degradation within 1 week after transfection in SCN neurons. However, dominant-negative BMAL1 did not translocate into the nucleus and the cytosolic signals persisted beyond 1 week. Consistently, circadian Ca(2+) rhythms in SCN neurons were inhibited for longer periods by dominant-negative Bmal1 overexpression. Furthermore, SCN neurons transfected with a Bmal1 shRNA lengthened, whereas those overexpressing wild-type Bmal1 shortened, the periods of Ca(2+) rhythms, with a significant reduction in their amplitude. BMAL1 expression was intact in the majority of neighboring neurons in organotypic cultures. Therefore, we conclude that proper intrinsic Bmal1 expression, but not passive signaling via cell-to-cell interactions, is the determinant of circadian Ca(2+) rhythms in SCN neurons.
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Wei H, Yasar H, Funk NW, Giese M, Baz ES, Stengl M. Signaling of pigment-dispersing factor (PDF) in the Madeira cockroach Rhyparobia maderae. PLoS One 2014; 9:e108757. [PMID: 25269074 PMCID: PMC4182629 DOI: 10.1371/journal.pone.0108757] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 08/05/2014] [Indexed: 11/19/2022] Open
Abstract
The insect neuropeptide pigment-dispersing factor (PDF) is a functional ortholog of vasoactive intestinal polypeptide, the coupling factor of the mammalian circadian pacemaker. Despite of PDF's importance for synchronized circadian locomotor activity rhythms its signaling is not well understood. We studied PDF signaling in primary cell cultures of the accessory medulla, the circadian pacemaker of the Madeira cockroach. In Ca²⁺ imaging studies four types of PDF-responses were distinguished. In regularly bursting type 1 pacemakers PDF application resulted in dose-dependent long-lasting increases in Ca²⁺ baseline concentration and frequency of oscillating Ca²⁺ transients. Adenylyl cyclase antagonists prevented PDF-responses in type 1 cells, indicating that PDF signaled via elevation of intracellular cAMP levels. In contrast, in type 2 pacemakers PDF transiently raised intracellular Ca²⁺ levels even after blocking adenylyl cyclase activity. In patch clamp experiments the previously characterized types 1-4 could not be identified. Instead, PDF-responses were categorized according to ion channels affected. Application of PDF inhibited outward potassium or inward sodium currents, sometimes in the same neuron. In a comparison of Ca²⁺ imaging and patch clamp experiments we hypothesized that in type 1 cells PDF-dependent rises in cAMP concentrations block primarily outward K⁺ currents. Possibly, this PDF-dependent depolarization underlies PDF-dependent phase advances of pacemakers. Finally, we propose that PDF-dependent concomitant modulation of K⁺ and Na⁺ channels in coupled pacemakers causes ultradian membrane potential oscillations as prerequisite to efficient synchronization via resonance.
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Affiliation(s)
- Hongying Wei
- University of Kassel, FB 10, Biology, Animal Physiology, Kassel, Germany
| | - Hanzey Yasar
- University of Kassel, FB 10, Biology, Animal Physiology, Kassel, Germany
| | - Nico W. Funk
- University of Kassel, FB 10, Biology, Animal Physiology, Kassel, Germany
| | - Maria Giese
- University of Kassel, FB 10, Biology, Animal Physiology, Kassel, Germany
| | - El-Sayed Baz
- University of Kassel, FB 10, Biology, Animal Physiology, Kassel, Germany
| | - Monika Stengl
- University of Kassel, FB 10, Biology, Animal Physiology, Kassel, Germany
- * E-mail:
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Iyer R, Wang TA, Gillette MU. Circadian gating of neuronal functionality: a basis for iterative metaplasticity. Front Syst Neurosci 2014; 8:164. [PMID: 25285070 PMCID: PMC4168688 DOI: 10.3389/fnsys.2014.00164] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 08/22/2014] [Indexed: 02/06/2023] Open
Abstract
Brain plasticity, the ability of the nervous system to encode experience, is a modulatory process leading to long-lasting structural and functional changes. Salient experiences induce plastic changes in neurons of the hippocampus, the basis of memory formation and recall. In the suprachiasmatic nucleus (SCN), the central circadian (~24-h) clock, experience with light at night induces changes in neuronal state, leading to circadian plasticity. The SCN's endogenous ~24-h time-generator comprises a dynamic series of functional states, which gate plastic responses. This restricts light-induced alteration in SCN state-dynamics and outputs to the nighttime. Endogenously generated circadian oscillators coordinate the cyclic states of excitability and intracellular signaling molecules that prime SCN receptivity to plasticity signals, generating nightly windows of susceptibility. We propose that this constitutes a paradigm of ~24-h iterative metaplasticity, the repeated, patterned occurrence of susceptibility to induction of neuronal plasticity. We detail effectors permissive for the cyclic susceptibility to plasticity. We consider similarities of intracellular and membrane mechanisms underlying plasticity in SCN circadian plasticity and in hippocampal long-term potentiation (LTP). The emerging prominence of the hippocampal circadian clock points to iterative metaplasticity in that tissue as well. Exploring these links holds great promise for understanding circadian shaping of synaptic plasticity, learning, and memory.
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Affiliation(s)
- Rajashekar Iyer
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign Urbana, IL, USA
| | - Tongfei A Wang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign Urbana, IL, USA
| | - Martha U Gillette
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign Urbana, IL, USA ; Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign Urbana, IL, USA
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Schendzielorz J, Schendzielorz T, Arendt A, Stengl M. Bimodal oscillations of cyclic nucleotide concentrations in the circadian system of the Madeira cockroach Rhyparobia maderae. J Biol Rhythms 2014; 29:318-31. [PMID: 25231947 DOI: 10.1177/0748730414546133] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Pigment-dispersing factor (PDF) is the most important coupling factor of the circadian system in insects, comparable to its functional ortholog vasoactive intestinal polypeptide of the mammalian circadian clock. In Drosophila melanogaster, PDF signals via activation of adenylyl cyclases, controlling circadian locomotor activity rhythms at dusk and dawn. In addition, PDF mediates circadian rhythms of the visual system and is involved in entrainment to different photoperiods. We examined whether PDF daytime-dependently elevates cAMP levels in the Madeira cockroach Rhyparobia maderae and whether cAMP mimics PDF effects on locomotor activity rhythms. To determine time windows of PDF release, we searched for circadian rhythms in concentrations of cAMP and its functional opponent cGMP in the accessory medulla (AMe), the insect circadian pacemaker controlling locomotor activity rhythms, and in the optic lobes, as the major input and output area of the circadian clock. Enzyme-linked immunosorbent assays detected PDF-dependent increases of cAMP in optic lobes and daytime-dependent oscillations of cAMP and cGMP baseline levels in the AMe, both with maxima at dusk and dawn. Although these rhythms disappeared at the first day in constant conditions (DD1), cAMP but not cGMP oscillations returned at the second day in constant conditions (DD2). Whereas in light-dark cycles the cAMP baseline level remained constant in other optic lobe neuropils, it oscillated in phase with the AMe at DD2. To determine whether cAMP and cGMP mimic PDF-dependent control of locomotor activity rhythms, both cyclic nucleotides were injected at different times of the circadian day using running-wheel assays. Whereas cAMP injections generated delays at dusk and advances at dawn, cGMP only delayed locomotor activity at dusk. For the first time we found PDF-dependent phase advances at dawn in addition to previously described phase delays at dusk. Thus, we hypothesize that PDF release at dusk and dawn controls locomotor activity rhythms and visual system processing cAMP-dependently.
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Affiliation(s)
- Julia Schendzielorz
- Department of Biology, Animal Physiology, University of Kassel, Kassel, Germany
| | | | - Andreas Arendt
- Department of Biology, Animal Physiology, University of Kassel, Kassel, Germany
| | - Monika Stengl
- Department of Biology, Animal Physiology, University of Kassel, Kassel, Germany
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Miro-Bueno J, Sosík P. Brain clock driven by neuropeptides and second messengers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:032705. [PMID: 25314471 DOI: 10.1103/physreve.90.032705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Indexed: 06/04/2023]
Abstract
The master circadian pacemaker in mammals is localized in a small portion of the brain called the suprachiasmatic nucleus (SCN). It is unclear how the SCN produces circadian rhythms. A common interpretation is that the SCN produces oscillations through the coupling of genetic oscillators in the neurons. The coupling is effected by a network of neuropeptides and second messengers. This network is crucial for the correct function of the SCN. However, models that study a possible oscillatory behavior of the network itself have received little attention. Here we propose and analyze a model to examine this oscillatory potential. We show that an intercellular oscillator emerges in the SCN as a result of the neuropeptide and second messenger dynamics. We find that this intercellular clock can produce circadian rhythms by itself with and without genetic clocks. We also found that the model is robust to perturbation of parameters and can be entrained by light-dark cycles.
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Affiliation(s)
- Jesus Miro-Bueno
- Research Institute of the IT4Innovations Centre of Excellence, Faculty of Philosophy and Science, Silesian University in Opava, 74601 Opava, Czech Republic
| | - Petr Sosík
- Research Institute of the IT4Innovations Centre of Excellence, Faculty of Philosophy and Science, Silesian University in Opava, 74601 Opava, Czech Republic and Departamento de Inteligencia Artificial, Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid, Madrid, Spain
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Pattanayak GK, Phong C, Rust MJ. Rhythms in energy storage control the ability of the cyanobacterial circadian clock to reset. Curr Biol 2014; 24:1934-8. [PMID: 25127221 PMCID: PMC4477845 DOI: 10.1016/j.cub.2014.07.022] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 07/07/2014] [Accepted: 07/09/2014] [Indexed: 01/27/2023]
Abstract
Circadian clocks are oscillatory systems that schedule daily rhythms of organismal behavior. The ability of the clock to reset its phase in response to external signals is critical for proper synchronization with the environment. In the model clock from cyanobacteria, the KaiABC proteins that comprise the core oscillator are directly sensitive to metabolites. Reduced ATP/ADP ratio and oxidized quinones cause clock phase shifts in vitro. However, it is unclear what determines the metabolic response of the cell to darkness and thus the magnitude of clock resetting. We show that the cyanobacterial circadian clock generates a rhythm in metabolism that causes cells to accumulate glycogen in anticipation of nightfall. Mutation of the histidine kinase CikA creates an insensitive clock-input phenotype by misregulating clock output genome wide, leading to overaccumulation of glycogen and subsequently high ATP in the dark. Conversely, we show that disruption of glycogen metabolism results in low ATP in the dark and makes the clock hypersensitive to dark pulses. The observed changes in cellular energy are sufficient to recapitulate phase-shifting phenotypes in an in vitro model of the clock. Our results show that clock-input phenotypes can arise from metabolic dysregulation and illustrate a framework for circadian biology where clock outputs feed back through metabolism to control input mechanisms.
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Affiliation(s)
- Gopal K Pattanayak
- Department of Molecular Genetics and Cell Biology, Institute for Genomics and Systems Biology, University of Chicago, 900 East 57(th) Street, Chicago, IL 60637, USA
| | - Connie Phong
- Department of Molecular Genetics and Cell Biology, Institute for Genomics and Systems Biology, University of Chicago, 900 East 57(th) Street, Chicago, IL 60637, USA
| | - Michael J Rust
- Department of Molecular Genetics and Cell Biology, Institute for Genomics and Systems Biology, University of Chicago, 900 East 57(th) Street, Chicago, IL 60637, USA.
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Circadian rhythm of hyperoxidized peroxiredoxin II is determined by hemoglobin autoxidation and the 20S proteasome in red blood cells. Proc Natl Acad Sci U S A 2014; 111:12043-8. [PMID: 25092340 DOI: 10.1073/pnas.1401100111] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The catalytic cysteine of the typical 2-Cys Prx subfamily of peroxiredoxins is occasionally hyperoxidized to cysteine sulfinic acid during the peroxidase catalytic cycle. Sulfinic Prx (Prx-SO2H) is reduced back to the active form of the enzyme by sulfiredoxin. The abundance of Prx-SO2H was recently shown to oscillate with a period of ∼24 h in human red blood cells (RBCs). We have now investigated the molecular mechanism and physiological relevance of such oscillation in mouse RBCs. Poisoning of RBCs with CO abolished Prx-SO2H formation, implicating H2O2 produced from hemoglobin autoxidation in Prx hyperoxidation. RBCs express the closely related PrxI and PrxII isoforms, and analysis of RBCs deficient in either isoform identified PrxII as the hyperoxidized Prx in these cells. Unexpectedly, RBCs from sulfiredoxin-deficient mice also exhibited circadian oscillation of Prx-SO2H. Analysis of the effects of protease inhibitors together with the observation that the purified 20S proteasome degraded PrxII-SO2H selectively over nonhyperoxidized PrxII suggested that the 20S proteasome is responsible for the decay phase of PrxII-SO2H oscillation. About 1% of total PrxII undergoes daily oscillation, resulting in a gradual loss of PrxII during the life span of RBCs. PrxII-SO2H was detected in cytosolic and ghost membrane fractions of RBCs, and the amount of membrane-bound PrxII-SO2H oscillated in a phase opposite to that of total PrxII-SO2H. Our results suggest that membrane association of PrxII-SO2H is a tightly controlled process and might play a role in the tuning of RBC function to environmental changes.
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Pauls S, Foley NC, Foley DK, LeSauter J, Hastings MH, Maywood ES, Silver R. Differential contributions of intra-cellular and inter-cellular mechanisms to the spatial and temporal architecture of the suprachiasmatic nucleus circadian circuitry in wild-type, cryptochrome-null and vasoactive intestinal peptide receptor 2-null mutant mice. Eur J Neurosci 2014; 40:2528-40. [PMID: 24891292 PMCID: PMC4159586 DOI: 10.1111/ejn.12631] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 04/22/2014] [Accepted: 04/23/2014] [Indexed: 12/11/2022]
Abstract
To serve as a robust internal circadian clock, the cell-autonomous molecular and electrophysiological activities of the individual neurons of the mammalian suprachiasmatic nucleus (SCN) are coordinated in time and neuroanatomical space. Although the contributions of the chemical and electrical interconnections between neurons are essential to this circuit-level orchestration, the features upon which they operate to confer robustness to the ensemble signal are not known. To address this, we applied several methods to deconstruct the interactions between the spatial and temporal organisation of circadian oscillations in organotypic slices from mice with circadian abnormalities. We studied the SCN of mice lacking Cryptochrome genes (Cry1 and Cry2), which are essential for cell-autonomous oscillation, and the SCN of mice lacking the vasoactive intestinal peptide receptor 2 (VPAC2-null), which is necessary for circuit-level integration, in order to map biological mechanisms to the revealed oscillatory features. The SCN of wild-type mice showed a strong link between the temporal rhythm of the bioluminescence profiles of PER2::LUC and regularly repeated spatially organised oscillation. The Cry-null SCN had stable spatial organisation but lacked temporal organisation, whereas in VPAC2-null SCN some specimens exhibited temporal organisation in the absence of spatial organisation. The results indicated that spatial and temporal organisation were separable, that they may have different mechanistic origins (cell-autonomous vs. interneuronal signaling) and that both were necessary to maintain robust and organised circadian rhythms throughout the SCN. This study therefore provided evidence that the coherent emergent properties of the neuronal circuitry, revealed in the spatially organised clusters, were essential to the pacemaking function of the SCN.
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Affiliation(s)
- S. Pauls
- Department of MathematicsDartmouth College6188 Kemeny HallHanoverNH03755USA
| | - N. C. Foley
- Department of NeuroscienceColumbia UniversityNew YorkNYUSA
| | - D. K. Foley
- Department of EconomicsNew School for Social ResearchNew YorkNYUSA
| | - J. LeSauter
- Department of PsychologyColumbia UniversityNew YorkNYUSA
| | - M. H. Hastings
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUK
| | - E. S. Maywood
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUK
| | - R. Silver
- Department of PsychologyColumbia UniversityNew YorkNYUSA
- Department of PsychologyBarnard College of Columbia UniversityNew YorkNYUSA
- Department of Pathology and Cell BiologyColumbia UniversityNew YorkNYUSA
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