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Inyushkin AN, Poletaev VS, Inyushkina EM, Kalberdin IS, Inyushkin AA. Irisin/BDNF signaling in the muscle-brain axis and circadian system: A review. J Biomed Res 2023; 38:1-16. [PMID: 38164079 PMCID: PMC10818175 DOI: 10.7555/jbr.37.20230133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 09/19/2023] [Accepted: 09/25/2023] [Indexed: 01/03/2024] Open
Abstract
In mammals, the timing of physiological, biochemical and behavioral processes over a 24-h period is controlled by circadian rhythms. To entrain the master clock located in the suprachiasmatic nucleus of the hypothalamus to a precise 24-h rhythm, environmental zeitgebers are used by the circadian system. This is done primarily by signals from the retina via the retinohypothalamic tract, but other cues like exercise, feeding, temperature, anxiety, and social events have also been shown to act as non-photic zeitgebers. The recently identified myokine irisin is proposed to serve as an entraining non-photic signal of exercise. Irisin is a product of cleavage and modification from its precursor membrane fibronectin type Ⅲ domain-containing protein 5 (FNDC5) in response to exercise. Apart from well-known peripheral effects, such as inducing the "browning" of white adipocytes, irisin can penetrate the blood-brain barrier and display the effects on the brain. Experimental data suggest that FNDC5/irisin mediates the positive effects of physical activity on brain functions. In several brain areas, irisin induces the production of brain-derived neurotrophic factor (BDNF). In the master clock, a significant role in gating photic stimuli in the retinohypothalamic synapse for BDNF is suggested. However, the brain receptor for irisin remains unknown. In the current review, the interactions of physical activity and the irisin/BDNF axis with the circadian system are reconceptualized.
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Affiliation(s)
- Alexey N. Inyushkin
- Department of Human & Animal Physiology, Samara National Research University, Samara 443011, Russia
| | - Vitalii S. Poletaev
- Department of Human & Animal Physiology, Samara National Research University, Samara 443011, Russia
| | - Elena M. Inyushkina
- Department of Human & Animal Physiology, Samara National Research University, Samara 443011, Russia
| | - Igor S. Kalberdin
- Department of Human & Animal Physiology, Samara National Research University, Samara 443011, Russia
| | - Andrey A. Inyushkin
- Department of Human & Animal Physiology, Samara National Research University, Samara 443011, Russia
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A Symphony of Signals: Intercellular and Intracellular Signaling Mechanisms Underlying Circadian Timekeeping in Mice and Flies. Int J Mol Sci 2019; 20:ijms20092363. [PMID: 31086044 PMCID: PMC6540063 DOI: 10.3390/ijms20092363] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/10/2019] [Accepted: 05/10/2019] [Indexed: 12/11/2022] Open
Abstract
The central pacemakers of circadian timekeeping systems are highly robust yet adaptable, providing the temporal coordination of rhythms in behavior and physiological processes in accordance with the demands imposed by environmental cycles. These features of the central pacemaker are achieved by a multi-oscillator network in which individual cellular oscillators are tightly coupled to the environmental day-night cycle, and to one another via intercellular coupling. In this review, we will summarize the roles of various neurotransmitters and neuropeptides in the regulation of circadian entrainment and synchrony within the mammalian and Drosophila central pacemakers. We will also describe the diverse functions of protein kinases in the relay of input signals to the core oscillator or the direct regulation of the molecular clock machinery.
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Moon E, Choe BM, Park JM, Chung YI, Lee BD, Park JH, Lee YM, Jeong HJ, Cheon Y, Choi Y, Park J. Protein Kinase C Activity and Delayed Recovery of Sleep-Wake Cycle in Mouse Model of Bipolar Disorder. Psychiatry Investig 2018; 15:907-913. [PMID: 30235919 PMCID: PMC6166033 DOI: 10.30773/pi.2018.05.23] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 05/23/2018] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Previous studies reported the delayed recovery group after circadian rhythm disruption in mice showed higher quinpiroleinduced locomotor activity. This study aimed to compare not only Protein Kinase C (PKC) activities in frontal, striatal, hippocampus and cerebellum, but also relative PKC activity ratios among brain regions according to recovery of circadian rhythm. METHODS The circadian rhythm disruption protocol was applied to eight-week-old twenty male Institute Cancer Research mice. The circadian rhythm recovery patterns were collected through motor activities measured by Mlog system. Depressive and manic proneness were examined by forced swim test and quinpirole-induced open field test respectively. Enzyme-linked immunosorbent assay was employed to measure PKC activities. RESULTS The delayed recovery group presented greater locomotor activities than the early recovery group (p=0.033). The delayed recovery group had significantly lower frontal PKC activity than the other (p=0.041). The former showed lower frontal/cerebellar PKC activity ratio (p=0.047) but higher striatal/frontal (p=0.038) and hippocampal/frontal (p=0.007) PKC activities ratios than the latter. CONCLUSION These findings support potential mechanism of delayed recovery after circadian disruption in bipolar animal model could be an alteration of relative PKC activities among mood regulation related brain regions. It is required to investigate the PKC downstream signaling related to the delayed recovery pattern.
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Affiliation(s)
- Eunsoo Moon
- Department of Psychiatry and Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Psychiatry, Pusan National University School of Medicine, Yangsan, Republic of Korea
| | - Byeong-Moo Choe
- Department of Psychiatry, Dong-A University School of Medicine, Busan, Republic of Korea
| | - Je-Min Park
- Department of Psychiatry and Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Psychiatry, Pusan National University School of Medicine, Yangsan, Republic of Korea
| | - Young In Chung
- Department of Psychiatry, Pusan National University School of Medicine, Yangsan, Republic of Korea
| | - Byung Dae Lee
- Department of Psychiatry and Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Psychiatry, Pusan National University School of Medicine, Yangsan, Republic of Korea
| | - Jae-Hong Park
- Department of Psychiatry, Dong-A University School of Medicine, Busan, Republic of Korea
| | - Young Min Lee
- Department of Psychiatry and Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Psychiatry, Pusan National University School of Medicine, Yangsan, Republic of Korea
| | - Hee Jeong Jeong
- Department of Psychiatry and Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - YongJun Cheon
- Department of Psychiatry, Dongrae Hospital, Busan, Republic of Korea
| | - Yoonmi Choi
- Department of Psychiatry and Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Jeonghyun Park
- Department of Psychiatry and Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
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Wheaton K, Aten S, Queiroz LS, Sullivan K, Oberdick J, Hoyt KR, Obrietan K. Circadian expression and functional characterization of PEA-15 within the mouse suprachiasmatic nucleus. Eur J Neurosci 2018; 47:845-857. [PMID: 29383758 DOI: 10.1111/ejn.13850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/15/2017] [Accepted: 01/15/2018] [Indexed: 12/14/2022]
Abstract
The circadian timing system influences the functional properties of most, if not all, physiological processes. Central to the mammalian timing system is the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN functions as a 'master clock' that sets the phasing of ancillary circadian oscillator populations found throughout the body. Further, via an entraining input from the retina, the SCN ensures that the clock oscillators are synchronized to the daily light/dark cycle. A critical component of the SCN timing and entrainment systems is the p44/42 mitogen-activated protein kinase (ERK/MAPK) pathway. Here, we examined the expression and function of phosphoprotein-enriched in astrocytes (PEA-15), an ERK scaffold protein that serves as a key regulator of MAPK signaling. A combination of immunolabeling and Western blotting approaches revealed high levels of PEA-15 within the SCN. PEA-15 expression was enriched in distinct subpopulations of SCN neurons, including arginine vasopressin (AVP)-positive neurons of the SCN shell region. Further, expression profiling detected a significant circadian oscillation in PEA-15 expression within the SCN. Brief photic stimulation during the early subjective night led to a significant increase in PEA-15 phosphorylation, an event that can trigger ERK/PEA-15 dissociation. Consistent with this, co-immunoprecipitation assays revealed that PEA-15 is directly bound to ERK in the SCN and that photic stimulation leads to their dissociation. Finally, we show that PEA-15 regulates ERK/MAPK-dependent activation of the core clock gene period1. Together, these data raise the prospect that PEA-15 functions as a key regulator of the SCN timing system.
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Affiliation(s)
- Kelin Wheaton
- Division of Pharmacology, Ohio State University, Columbus, OH, 43210, USA
| | - Sydney Aten
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | | | - Kyle Sullivan
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | - John Oberdick
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | - Kari R Hoyt
- Division of Pharmacology, Ohio State University, Columbus, OH, 43210, USA
| | - Karl Obrietan
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
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Mendoza-Viveros L, Bouchard-Cannon P, Hegazi S, Cheng AH, Pastore S, Cheng HYM. Molecular modulators of the circadian clock: lessons from flies and mice. Cell Mol Life Sci 2017; 74:1035-1059. [PMID: 27689221 PMCID: PMC11107503 DOI: 10.1007/s00018-016-2378-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 09/03/2016] [Accepted: 09/22/2016] [Indexed: 12/16/2022]
Abstract
Circadian timekeeping is a ubiquitous mechanism that enables organisms to maintain temporal coordination between internal biological processes and time of the local environment. The molecular basis of circadian rhythms lies in a set of transcription-translation feedback loops (TTFLs) that drives the rhythmic transcription of core clock genes, whose level and phase of expression serve as the marker of circadian time. However, it has become increasingly evident that additional regulatory mechanisms impinge upon the TTFLs to govern the properties and behavior of the circadian clock. Such mechanisms include changes in chromatin architecture, interactions with other transcription factor networks, post-transcriptional control by RNA modifications, alternative splicing and microRNAs, and post-translational regulation of subcellular trafficking and protein degradation. In this review, we will summarize the current knowledge of circadian clock regulation-from transcriptional to post-translational-drawing from literature pertaining to the Drosophila and murine circadian systems.
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Affiliation(s)
- Lucia Mendoza-Viveros
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Pascale Bouchard-Cannon
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Sara Hegazi
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Arthur H Cheng
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Stephen Pastore
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Hai-Ying Mary Cheng
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada.
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada.
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Sánchez-Bretaño A, Blanco AM, Alonso-Gómez ÁL, Delgado MJ, Kah O, Isorna E. Ghrelin induces clock gene expression in the liver of goldfish in vitro via protein kinase C and protein kinase A pathways. ACTA ACUST UNITED AC 2017; 220:1295-1306. [PMID: 28126833 DOI: 10.1242/jeb.144253] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 01/23/2017] [Indexed: 01/02/2023]
Abstract
The liver is the most important link between the circadian system and metabolism. As a food-entrainable oscillator, the hepatic clock needs to be entrained by food-related signals. The objective of the present study was to investigate the possible role of ghrelin (an orexigenic peptide mainly synthesized in the gastrointestinal tract) as an endogenous synchronizer of the liver oscillator in teleosts. To achieve this aim, we first examined the presence of ghrelin receptors in the liver of goldfish. Then, the ghrelin regulation of clock gene expression in the goldfish liver was studied. Finally, the possible involvement of the phospholipase C/protein kinase C (PLC/PKC) and adenylate cyclase/protein kinase A (AC/PKA) intracellular signalling pathways was investigated. Ghrelin receptor transcripts, ghs-r1a, are present in the majority of goldfish hepatic cells. Ghrelin induced the mRNA expression of the positive (gbmal1a, gclock1a) and negative (gper genes) elements of the main loop of the molecular clock machinery, as well as grev-erbα (auxiliary loop) in cultured liver. These effects were blocked, at least in part, by a ghrelin antagonist. Incubation of liver with a PLC inhibitor (U73122), a PKC activator (phorbol 12-myristate 13-acetate) and a PKC inhibitor (chelerythrine chloride) demonstrated that the PLC/PKC pathway mediates such ghrelin actions. Experiments with an AC activator (forskolin) and a PKA inhibitor (H89) showed that grev-erbα regulation could be due to activation of PKA. Taken together, the present results show for the first time in vertebrates a direct action of ghrelin on hepatic clock genes and support a role for this hormone as a temporal messenger in the entrainment of liver circadian functions.
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Affiliation(s)
- Aída Sánchez-Bretaño
- Animal Physiology Department, Faculty of Biology, Complutense University of Madrid, Madrid 28040, Spain
| | - Ayelén M Blanco
- Animal Physiology Department, Faculty of Biology, Complutense University of Madrid, Madrid 28040, Spain
| | - Ángel L Alonso-Gómez
- Animal Physiology Department, Faculty of Biology, Complutense University of Madrid, Madrid 28040, Spain
| | - María J Delgado
- Animal Physiology Department, Faculty of Biology, Complutense University of Madrid, Madrid 28040, Spain
| | - Olivier Kah
- Neuroendocrine Effects of Endocrine Disruptors, Inserm (Research Institute for Health, Environment and Occupation, IRSET, INSERM U1085), SFR Biosit Université de Rennes 1, 35000 Rennes, France
| | - Esther Isorna
- Animal Physiology Department, Faculty of Biology, Complutense University of Madrid, Madrid 28040, Spain
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Yu J, Chen J, Hu T, Guo S, Wang X, Guo Y, Chen X, Zhao C. Effect of Electro-Acupuncture on Expression of Circadian Clock Gene Per2 and Bmal1 in Sleep Deprivation Rat. Chin Med 2016. [DOI: 10.4236/cm.2016.71003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Ling HH, Mendoza-Viveros L, Mehta N, Cheng HYM. Raf kinase inhibitory protein (RKIP): functional pleiotropy in the mammalian brain. Crit Rev Oncog 2015; 19:505-16. [PMID: 25597360 DOI: 10.1615/critrevoncog.2014011899] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In 1984, a cytosolic protein was isolated from bovine brain and coined phosphatidylethanolamine binding protein (PEBP) to describe its phospholipid-binding potential. Its cellular function remained elusive for more than a decade until it was discovered that PEBP had the ability to suppress the Raf1-mitogen activated protein kinase (MAPK) pathway, earning it the new name of Raf1 kinase inhibitory protein (RKIP). This milestone discovery has paved the way for numerous studies that have now extended the reach of RKIP's function to other signaling cascades, within the context of various physiological and pathophysiological systems. This review will summarize our current knowledge of the neurophysiological roles of RKIP in the mammalian brain, including its function in the circadian clock and synaptic plasticity. It will also discuss evidence for an involvement of RKIP and its derived neuropeptide, hippocampal cholinergic neurostimulating peptide (HCNP), in neural development and differentiation. Implications in certain pathologies such as Alzheimer's disease and brain cancer will be highlighted. By chronicling the diverse functions of RKIP in the brain, we hope that this review will serve as a timely resource that ignites future studies on this versatile, multifaceted protein in the nervous system.
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Affiliation(s)
- Harrod H Ling
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Lucia Mendoza-Viveros
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Neel Mehta
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Hai-Ying M Cheng
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
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Paydar A, Lee B, Gangadharan G, Lee S, Hwang EM, Shin HS. Extrasynaptic GABAA receptors in mediodorsal thalamic nucleus modulate fear extinction learning. Mol Brain 2014; 7:39. [PMID: 24886120 PMCID: PMC4066285 DOI: 10.1186/1756-6606-7-39] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 05/23/2014] [Indexed: 11/14/2022] Open
Abstract
Background The gamma-amino-butyric acid (GABA) system is a critical mediator of fear extinction process. GABA can induce “phasic” or “tonic” inhibition in neurons through synaptic or extrasynaptic GABAA receptors, respectively. However, role of the thalamic “tonic GABA inhibition” in cognition has not been explored. We addressed this issue in extinction of conditioned fear in mice. Results Here, we show that GABAA receptors in the mediodorsal thalamic nucleus (MD) modulate fear extinction. Microinjection of gabazine, a GABAA receptor antagonist, into the MD decreased freezing behavior in response to the conditioned stimulus and thus facilitated fear extinction. Interestingly, microinjection of THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol), a preferential agonist for the δ-subunit of extrasynaptic GABAA receptors, into the MD attenuated fear extinction. In the opposite direction, an MD-specific knock-out of the extrasynaptic GABAA receptors facilitated fear extinction. Conclusions Our results suggest that “tonic GABA inhibition” mediated by extrasynaptic GABAA receptors in MD neurons, suppresses fear extinction learning. These results raise a possibility that pharmacological control of tonic mode of GABAA receptor activation may be a target for treatment of anxiety disorders like post-traumatic stress disorder.
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Affiliation(s)
| | | | | | | | | | - Hee-Sup Shin
- Center for Cognition and Sociality, Institute for Basic Science (IBS), 70, Yusung-daero 1689-gil, Yusung-gu, Daejeon 305-811, Republic of Korea.
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Bonsall DR, Lall GS. Protein Kinase C Differentially Regulates Entrainment of the Mammalian Circadian Clock. Chronobiol Int 2013; 30:460-9. [DOI: 10.3109/07420528.2012.741170] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Regulation of MAPK/ERK signaling and photic entrainment of the suprachiasmatic nucleus circadian clock by Raf kinase inhibitor protein. J Neurosci 2012; 32:4867-77. [PMID: 22492043 DOI: 10.1523/jneurosci.5650-11.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Activation of the MAPK/ERK signaling cascade in the suprachiasmatic nucleus (SCN) is a key event that couples light to circadian clock entrainment. However, we do not fully understand the mechanisms that shape the properties of MAPK/ERK signaling in the SCN, and how these mechanisms may influence overt circadian rhythms. Here we show that Raf kinase inhibitor protein (RKIP) controls the kinetics of light-induced MAPK/ERK activity in the SCN and photic entrainment of behavioral rhythms. Light triggers robust phosphorylation of RKIP in the murine SCN and dissociation of RKIP and c-Raf. Overexpression of a nonphosphorylatable form of RKIP in the SCN of transgenic mice blocks light-induced ERK1/2 activation in the SCN and severely dampens light-induced phase delays in behavioral rhythms. Conversely, in RKIP knock-out (RKIP(-/-)) mice, light-induced ERK1/2 activity in the SCN is prolonged in the early and late subjective night, resulting in augmentation of the phase-delaying and -advancing effects of light. Reentrainment to an advancing light cycle was also accelerated in RKIP(-/-) mice. In relation to the molecular clockwork, genetic deletion of RKIP potentiated light-evoked PER1 and PER2 protein expression in the SCN in the early night. Additionally, RKIP(-/-) mice displayed enhanced transcriptional activation of mPeriod1 and the immediate early gene c-Fos in the SCN in response to a phase-delaying light pulse. Collectively, our data reveal an important role of RKIP in the regulation of MAPK/ERK signaling in the SCN and photic entrainment of the SCN clock.
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Epigenetic Control of Circadian Clock Operation during Development. GENETICS RESEARCH INTERNATIONAL 2012; 2012:845429. [PMID: 22567402 PMCID: PMC3335631 DOI: 10.1155/2012/845429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 12/22/2011] [Accepted: 01/13/2012] [Indexed: 11/17/2022]
Abstract
The molecular players of circadian clock oscillation have been identified and extensively characterized. The epigenetic mechanisms behind the circadian gene expression control has also been recently studied, although there are still details to be illucidated. In this review, we briefly summarize the current understanding of the mammalian clock. We also provide evidence for the lack of circadian oscillation in particular cell types. As the circadian clock has intimate interaction with the various cellular functions in different type of cells, it must have plasticity and specicity in its operation within different epigenetic environments. The lack of circadian oscillation in certain cells provide an unique opportunity to study the required epigenetic environment in the cell that permit circadian oscillation and to idenfify key influencing factors for proper clock function. How epigenetic mechansims, including DNA methylaiton and chromatin modifications, participate in control of clock oscillation still awaits future studies at the genomic scale.
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O'Neill AK, Niederst MJ, Newton AC. Suppression of survival signalling pathways by the phosphatase PHLPP. FEBS J 2012; 280:572-83. [PMID: 22340730 DOI: 10.1111/j.1742-4658.2012.08537.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The recently discovered pleckstrin homology (PH) domain leucine-rich repeat protein phosphatase (PHLPP) family is emerging as a central component in suppressing cell survival pathways. Originally discovered in a rational search for a phosphatase that directly dephosphorylates and inactivates Akt, PHLPP is now known to potently suppress cell survival both by inhibiting proliferative pathways and by promoting apoptotic pathways. In the first instance, PHLPP directly dephosphorylates a conserved regulatory site (termed the hydrophobic motif) on Akt, protein kinase C and S6 kinase, thereby terminating signalling by these pro-survival kinases. In the second instance, PHLPP dephosphorylates and thus activates the pro-apoptotic kinase Mst1, thereby promoting apoptosis. PHLPP is deleted in a large number of cancers and the genetic deletion of one isozyme in a PTEN (phosphatase and tensin homologue located on chromosome 1) +/- (or heterozygous) prostate cancer model results in increased tumourigenesis, underscoring the role of PHLPP as a tumour suppressor. This review summarizes the targets and cellular actions of PHLPP, with emphasis on its role as a tumour suppressor in the oncogenic phosphoinositide 3-kinase (PI3K)/Akt signalling cascade.
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Affiliation(s)
- Audrey K O'Neill
- Biomedical Sciences Graduate Program, University of California, San Diego, CA 92093-0721, USA
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14
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The cholinergic system, circadian rhythmicity, and time memory. Behav Brain Res 2011; 221:466-80. [DOI: 10.1016/j.bbr.2010.11.039] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 11/19/2010] [Accepted: 11/22/2010] [Indexed: 01/23/2023]
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15
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Lee B, Li A, Hansen KF, Cao R, Yoon JH, Obrietan K. CREB influences timing and entrainment of the SCN circadian clock. J Biol Rhythms 2011; 25:410-20. [PMID: 21135157 DOI: 10.1177/0748730410381229] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The transcriptional feedback circuit, which is at the core of the suprachiasmatic nucleus (SCN) circadian (i.e., 24 h) clock, is tightly coupled to both external entrainment cues, such as light, as well as rhythmic cues that arise on a system-wide level within the SCN. One potential signaling pathway by which these cues are conveyed to the molecular clock is the CREB/CRE transcriptional cascade. In this study, we employed a tetracycline-inducible CREB repressor mouse strain, in which approximately 60% of the SCN neurons express the transgene, to test CREB functionality in the clock and its effects on overt rhythmicity. We show that attenuated CREB signaling in the SCN led to a significant reduction in light-evoked clock entrainment. An examination of circadian timing revealed that CREB repressor mice exhibited normal free-running rhythms in the absence of external lighting cues. However, under conditions of constant light, which typically leads to a lengthening of the circadian period, CREB repressor mice exhibited a dramatic arrhythmic phenotype, which could be reversed with doxycycline. At a cellular level, the repression of CREB led to a significant reduction in both the expression of the circadian clock proteins PERIOD1 and PERIOD2 and the clock output hormones AVP and VIP. Together, these data support the idea that the CRE transcriptional pathway orchestrates transcriptional events that are essential for both the maintenance of SCN timing and light entrainment of the circadian clock.
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Affiliation(s)
- Boyoung Lee
- Department of Neuroscience, Ohio State University, Columbus, OH, USA
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Gamble KL, Kudo T, Colwell CS, McMahon DG. Gastrin-releasing peptide modulates fast delayed rectifier potassium current in Per1-expressing SCN neurons. J Biol Rhythms 2011; 26:99-106. [PMID: 21454290 PMCID: PMC3148520 DOI: 10.1177/0748730410396678] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The mammalian circadian clock in the suprachiasmatic nucleus (SCN) drives and maintains 24-h physiological rhythms, the phases of which are set by the local environmental light-dark cycle. Gastrin-releasing peptide (GRP) communicates photic phase setting signals in the SCN by increasing neurophysiological activity of SCN neurons. Here, the ionic basis for persistent GRP-induced changes in neuronal activity was investigated in SCN slice cultures from Per1::GFP reporter mice during the early night. Recordings from Per1 -fluorescent neurons in SCN slices several hours after GRP treatment revealed a significantly greater action potential frequency, a significant increase in voltage-activated outward current at depolarized potentials, and a significant increase in 4-aminopyridine-sensitive fast delayed rectifier (fDR) potassium currents when compared to vehicle-treated slices. In addition, the persistent increase in spike rate following early-night GRP application was blocked in SCN neurons from mice deficient in Kv3 channel proteins. Because fDR currents are regulated by the clock and are elevated in amplitude during the day, the present results support the model that GRP delays the phase of the clock during the early night by prolonging day-like membrane properties of SCN cells. Furthermore, these findings implicate fDR currents in the ionic basis for GRP-mediated entrainment of the primary mammalian circadian pacemaker.
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Affiliation(s)
- Karen L. Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL
| | - Takashi Kudo
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA
| | - Christopher S. Colwell
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA
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Khatun R, Lakin-Thomas P. Activation and localization of protein kinase C in Neurospora crassa. Fungal Genet Biol 2011; 48:465-73. [DOI: 10.1016/j.fgb.2010.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 11/01/2010] [Accepted: 11/02/2010] [Indexed: 11/28/2022]
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18
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Kim SH, Kim MK, Yu HS, Kim HS, Park IS, Park HG, Kang UG, Kim YS. Electroconvulsive seizure increases phosphorylation of PKC substrates, including GAP-43, MARCKS, and neurogranin, in rat brain. Prog Neuropsychopharmacol Biol Psychiatry 2010; 34:115-21. [PMID: 19837121 DOI: 10.1016/j.pnpbp.2009.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 10/08/2009] [Accepted: 10/08/2009] [Indexed: 01/06/2023]
Abstract
Protein kinase C (PKC) has been suggested as a molecular target related to the pathogenetic and therapeutic mechanisms of mood disorders in which electroconvulsive seizure (ECS) is effective. However, the reports concerning the effects of ECS on PKC are anecdotal and need further clarification. In this study, we examined the effects of ECS treatment on the phosphorylation of PKC substrates, including GAP-43, MARCKS, and neurogranin. Immunoblot using anti-p-PKC substrate antibodies revealed that a single ECS treatment induced temporal changes in the phosphorylation level of PKC substrates in rat brain, reflecting the effects on PKC activity. Phosphorylation of GAP-43 and MARCKS, representative PKC substrates related to synaptic remodeling, increased from 5 to 30 min, after a transient decrease at 0 min immediately after ECS, and returned to basal levels at 60 min in rat frontal cortex, hippocampus, and cerebellum. Phosphorylation of neurogranin, another PKC substrate, showed a similar pattern of temporal changes in the frontal cortex and hippocampus. Immunohistochemical analysis revealed that p-GAP-43 and p-MARCKS were densely stained throughout the neuronal cells of the prefrontal cortex and hippocampus, and the Purkinje cells of cerebellum, after ECS treatment. Brief and transient activation of PKC may be translated into long-term biochemical changes, resulting in synaptic plasticity. Taken together, the acute effects of ECS on PKC activity, which could be an underpinning of long-term biochemical changes induced by ECS, may contribute to understand the molecular mechanism of ECS.
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Affiliation(s)
- Se Hyun Kim
- Department of Psychiatry and Behavioral Science and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
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19
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Robles MS, Boyault C, Knutti D, Padmanabhan K, Weitz CJ. Identification of RACK1 and protein kinase Calpha as integral components of the mammalian circadian clock. Science 2010; 327:463-6. [PMID: 20093473 DOI: 10.1126/science.1180067] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
At the core of the mammalian circadian clock is a negative feedback loop in which the dimeric transcription factor CLOCK-BMAL1 drives processes that in turn suppress its transcriptional activity. To gain insight into the mechanisms of circadian feedback, we analyzed mouse protein complexes containing BMAL1. Receptor for activated C kinase-1 (RACK1) and protein kinase C-alpha (PKCalpha) were recruited in a circadian manner into a nuclear BMAL1 complex during the negative feedback phase of the cycle. Overexpression of RACK1 and PKCalpha suppressed CLOCK-BMAL1 transcriptional activity, and RACK1 stimulated phosphorylation of BMAL1 by PKCalpha in vitro. Depletion of endogenous RACK1 or PKCalpha from fibroblasts shortened the circadian period, demonstrating that both molecules function in the clock oscillatory mechanism. Thus, the classical PKC signaling pathway is not limited to relaying external stimuli but is rhythmically activated by internal processes, forming an integral part of the circadian feedback loop.
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Affiliation(s)
- Maria S Robles
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
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20
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Antle MC, Smith VM, Sterniczuk R, Yamakawa GR, Rakai BD. Physiological responses of the circadian clock to acute light exposure at night. Rev Endocr Metab Disord 2009; 10:279-91. [PMID: 19768549 DOI: 10.1007/s11154-009-9116-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Circadian rhythms in physiological, endocrine and metabolic functioning are controlled by a neural clock located in the suprachiasmatic nucleus (SCN). This structure is endogenously rhythmic and the phase of this rhythm can be reset by light information from the eye. A key feature of the SCN is that while it is a small structure containing on the order of about 20,000 cells, it is amazingly heterogeneous. It is likely that anatomical heterogeneity reflects an underlying functional heterogeneity. In this review, we examine the physiological responses of cells in the SCN to light stimuli that reset the phase of the circadian clock, highlighting where possible the spatial pattern of such responses. Increases in intracellular calcium are an important signal in response to light, and this increase triggers many biochemical cascades that mediate responses to light. Furthermore, only some cells in the SCN are actually endogenously rhythmic, and these cells likely do not receive strong direct input from the retina. Therefore, this review also considers how light information is conveyed from the retinorecipient cells to the endogenously rhythmic cells that track circadian phase. A number of neuropeptides, including vasoactive intestinal polypeptide, gastrin-releasing peptide and substance P, may be particularly important in relaying such signals, but other neurochemicals such as GABA and nitric oxide may participate as well. A thorough understanding of the intracellular and intercellular responses to light, as well as the spatial arrangements of such responses may help identify important pharmacological targets for therapeutic interventions to treat sleep and circadian disorders.
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Affiliation(s)
- Michael C Antle
- Department of Psychology, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
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21
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Shimizu K, Mackenzie SM, Storm DR. SCOP/PHLPP and its functional role in the brain. MOLECULAR BIOSYSTEMS 2009; 6:38-43. [PMID: 20024065 DOI: 10.1039/b911410f] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
SCOP (suprachiasmatic nucleus (SCN) circadian oscillatory protein) was originally identified in 1999 in a differential display screen of the rat SCN for genes whose expression were regulated in a circadian manner (K. Shimizu, M. Okada, A. Takano and K. Nagai, FEBS Lett., 1999, 458, 363-369). The SCN is the principle pacemaker of the circadian clock, and expression of SCOP protein in the SCN was found to oscillate, increasing during the subjective night, even when animals were housed in constant darkness. SCOP interacts with and inhibits multiple proteins important for intracellular signaling, either by directly binding to K-Ras or by dephosphorylating p-Akt and p-PKC. Since the functions of K-Ras, Akt, and PKC are considerably divergent, SCOP may have several roles. We recently discovered that SCOP participates in the formation of long-term hippocampus-dependent memories, and other investigators have examined its role in cell proliferation and survival. In this review, we introduce SCOP from its molecular structure to its physiological functions, focusing mainly on its role in ERK1/2 activation and memory consolidation.
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Affiliation(s)
- Kimiko Shimizu
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
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Toh KL. Basic Science Review on Circadian Rhythm Biology and Circadian Sleep Disorders. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2008. [DOI: 10.47102/annals-acadmedsg.v37n8p662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The sleep-wake cycle displays a characteristic 24-hour periodicity, providing an opportunity to dissect the endogenous circadian clock through the study of aberrant behaviour. This article surveys the properties of circadian clocks, with emphasis on mammals. Information was obtained from searches of peer-reviewed literature in the PUBMED database. Features that are highlighted include the known molecular components of clocks, their entrainment by external time cues and the output pathways used by clocks to regulate metabolism and behaviour. A review of human circadian rhythm sleep disorders follows, including recent discoveries of their genetic basis. The article concludes with a discussion of future approaches to the study of human circadian biology and sleep-wake behaviour.
Key words: Circadian clocks, Entrainment, Human circadian sleep-wake disorders
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Kessler EJ, Sprouse J, Harrington ME. NAN-190 potentiates the circadian response to light and speeds re-entrainment to advanced light cycles. Neuroscience 2008; 154:1187-94. [PMID: 18538936 DOI: 10.1016/j.neuroscience.2008.04.054] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 04/01/2008] [Accepted: 04/18/2008] [Indexed: 11/30/2022]
Abstract
Health problems can arise from de-synchrony between the external environment and the endogenous circadian rhythm, yet the circadian system is not able to quickly adjust to large, abrupt changes in the external daily cycle. In this study, we investigated the ability of NAN-190 to potentiate the circadian rhythm response to light as measured by phase of behavioral activity rhythms. NAN-190 (5 mg/kg, i.p.) was able to significantly potentiate the response to light both in dark-adapted and entrained hamsters. Furthermore, NAN-190 was effective even when administered up to 6 h after light onset. Response to a light pulse was both greater in magnitude and involved fewer unstable transient cycles. Finally, NAN-190 was able to speed re-entrainment to a 6 h advance of the light/dark cycle by an average of 6 days when compared with vehicle-treated animals. This work suggests that compounds like NAN-190 may hold great potential as a pharmaceutical treatment for jetlag, shift work, and other circadian disorders.
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Affiliation(s)
- E J Kessler
- Neuroscience Program, Smith College, Northampton, MA 01063, USA
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Cao R, Lee B, Cho HY, Saklayen S, Obrietan K. Photic regulation of the mTOR signaling pathway in the suprachiasmatic circadian clock. Mol Cell Neurosci 2008; 38:312-24. [PMID: 18468454 DOI: 10.1016/j.mcn.2008.03.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 02/18/2008] [Accepted: 03/13/2008] [Indexed: 01/02/2023] Open
Abstract
Here we analyzed the light-responsiveness of the mammalian target of rapamycin (mTOR) cascade, a key regulator of inducible translation, in the suprachiasmatic nuclei (SCN), the locus of the master circadian clock. Brief light exposure during the subjective night, but not during the subjective day, triggered rapid phosphorylation (a marker of catalytic activity) of the mTOR translation effectors p70 S6K, ribosomal S6 protein (S6) and 4E-BP1. In the absence of photic stimulation, marked S6 and 4E-BP1 phosphorylation was detected, indicating tonic mTOR activity in the SCN. Light stimulated the colocalized activation of p70 S6K and extracellular signal-regulated protein kinase (ERK), and pharmacological disruption of ERK signaling abolished light-induced mTOR activity, revealing that the MAPK cascade is an essential intermediate that couples light to mTOR. Together these data identify a light-responsive mTOR cascade in the SCN, and thus, raise the possibility that inducible translation contributes to the clock entrainment process.
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Affiliation(s)
- Ruifeng Cao
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA
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