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Rodan AR. Circadian Rhythm Regulation by Pacemaker Neuron Chloride Oscillation in Flies. Physiology (Bethesda) 2024; 39:0. [PMID: 38411570 PMCID: PMC11368518 DOI: 10.1152/physiol.00006.2024] [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: 01/23/2024] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 02/28/2024] Open
Abstract
Circadian rhythms in physiology and behavior sync organisms to external environmental cycles. Here, circadian oscillation in intracellular chloride in central pacemaker neurons of the fly, Drosophila melanogaster, is reviewed. Intracellular chloride links SLC12 cation-coupled chloride transporter function with kinase signaling and the regulation of inwardly rectifying potassium channels.
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Affiliation(s)
- Aylin R Rodan
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States
- Department of Internal Medicine, Division of Nephrology and Hypertension, University of Utah, Salt Lake City, Utah, United States
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States
- Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah, United States
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2
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Stengl M, Schneider AC. Contribution of membrane-associated oscillators to biological timing at different timescales. Front Physiol 2024; 14:1243455. [PMID: 38264332 PMCID: PMC10803594 DOI: 10.3389/fphys.2023.1243455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 12/12/2023] [Indexed: 01/25/2024] Open
Abstract
Environmental rhythms such as the daily light-dark cycle selected for endogenous clocks. These clocks predict regular environmental changes and provide the basis for well-timed adaptive homeostasis in physiology and behavior of organisms. Endogenous clocks are oscillators that are based on positive feedforward and negative feedback loops. They generate stable rhythms even under constant conditions. Since even weak interactions between oscillators allow for autonomous synchronization, coupling/synchronization of oscillators provides the basis of self-organized physiological timing. Amongst the most thoroughly researched clocks are the endogenous circadian clock neurons in mammals and insects. They comprise nuclear clockworks of transcriptional/translational feedback loops (TTFL) that generate ∼24 h rhythms in clock gene expression entrained to the environmental day-night cycle. It is generally assumed that this TTFL clockwork drives all circadian oscillations within and between clock cells, being the basis of any circadian rhythm in physiology and behavior of organisms. Instead of the current gene-based hierarchical clock model we provide here a systems view of timing. We suggest that a coupled system of autonomous TTFL and posttranslational feedback loop (PTFL) oscillators/clocks that run at multiple timescales governs adaptive, dynamic homeostasis of physiology and behavior. We focus on mammalian and insect neurons as endogenous oscillators at multiple timescales. We suggest that neuronal plasma membrane-associated signalosomes constitute specific autonomous PTFL clocks that generate localized but interlinked oscillations of membrane potential and intracellular messengers with specific endogenous frequencies. In each clock neuron multiscale interactions of TTFL and PTFL oscillators/clocks form a temporally structured oscillatory network with a common complex frequency-band comprising superimposed multiscale oscillations. Coupling between oscillator/clock neurons provides the next level of complexity of an oscillatory network. This systemic dynamic network of molecular and cellular oscillators/clocks is suggested to form the basis of any physiological homeostasis that cycles through dynamic homeostatic setpoints with a characteristic frequency-band as hallmark. We propose that mechanisms of homeostatic plasticity maintain the stability of these dynamic setpoints, whereas Hebbian plasticity enables switching between setpoints via coupling factors, like biogenic amines and/or neuropeptides. They reprogram the network to a new common frequency, a new dynamic setpoint. Our novel hypothesis is up for experimental challenge.
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Affiliation(s)
- Monika Stengl
- Department of Biology, Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
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3
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Gundermann DG, Lymer S, Blau J. A rapid and dynamic role for FMRP in the plasticity of adult neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.01.555985. [PMID: 37693612 PMCID: PMC10491314 DOI: 10.1101/2023.09.01.555985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Fragile X syndrome (FXS) is a neuro-developmental disorder caused by silencing Fmr1, which encodes the RNA-binding protein FMRP. Although Fmr1 is expressed in adult neurons, it has been challenging to separate acute from chronic effects of loss of Fmr1 in models of FXS. We have used the precision of Drosophila genetics to test if Fmr1 acutely affects adult neuronal plasticity in vivo, focusing on the s-LNv circadian pacemaker neurons that show 24 hour rhythms in structural plasticity. We found that over-expressing Fmr1 for only 4 hours blocks the activity-dependent expansion of s-LNv projections without altering the circadian clock or activity-regulated gene expression. Conversely, acutely reducing Fmr1 expression prevented s-LNv projections from retracting. One FMRP target that we identified in s-LNvs is sif, which encodes a Rac1 GEF. Our data indicate that FMRP normally reduces sif mRNA translation at dusk to reduce Rac1 activity. Overall, our data reveal a previously unappreciated rapid and direct role for FMRP in acutely regulating neuronal plasticity in adult neurons, and underscore the importance of RNA-binding proteins in this process.
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Affiliation(s)
- Daniel G Gundermann
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Seana Lymer
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
- Current address: Proteintech Genomics, 11588 Sorrento Valley Rd, San Diego, CA 92121
| | - Justin Blau
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, UAE
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4
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Iyer AR, Sheeba V. A new player in circadian networks: Role of electrical synapses in regulating functions of the circadian clock. Front Physiol 2022; 13:968574. [PMID: 36406999 PMCID: PMC9669436 DOI: 10.3389/fphys.2022.968574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022] Open
Abstract
Several studies have indicated that coherent circadian rhythms in behaviour can be manifested only when the underlying circadian oscillators function as a well-coupled network. The current literature suggests that circadian pacemaker neuronal networks rely heavily on communication mediated by chemical synapses comprising neuropeptides and neurotransmitters to regulate several behaviours and physiological processes. It has become increasingly clear that chemical synapses closely interact with electrical synapses and function together in the neuronal networks of most organisms. However, there are only a few studies which have examined the role of electrical synapses in circadian networks and here, we review our current understanding of gap junction proteins in circadian networks of various model systems. We describe the general mechanisms by which electrical synapses function in neural networks, their interactions with chemical neuromodulators and their contributions to the regulation of circadian rhythms. We also discuss the various methods available to characterize functional electrical synapses in these networks and the potential directions that remain to be explored to understand the roles of this relatively understudied mechanism of communication in modulating circadian behaviour.
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Affiliation(s)
- Aishwarya Ramakrishnan Iyer
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
- Department of Neuroscience and Behavior, Barnard College of Columbia University, New York, NY, United States
| | - Vasu Sheeba
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
- *Correspondence: Vasu Sheeba,
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5
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Tang M, Cao LH, Yang T, Ma SX, Jing BY, Xiao N, Xu S, Leng KR, Yang D, Li MT, Luo DG. An extra-clock ultradian brain oscillator sustains circadian timekeeping. SCIENCE ADVANCES 2022; 8:eabo5506. [PMID: 36054358 PMCID: PMC10848952 DOI: 10.1126/sciadv.abo5506] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
The master circadian clock generates 24-hour rhythms to orchestrate daily behavior, even running freely under constant conditions. Traditionally, the master clock is considered self-sufficient in sustaining free-running timekeeping via its cell-autonomous molecular clocks and interneuronal communications within the circadian neural network. Here, we find a set of bona fide ultradian oscillators in the Drosophila brain that support free-running timekeeping, despite being located outside the master clock circuit and lacking clock gene expression. These extra-clock electrical oscillators (xCEOs) generate cell-autonomous ultradian bursts, pacing widespread burst firing and promoting rhythmic resting membrane potentials in clock neurons via parallel monosynaptic connections. Silencing xCEOs disrupts daily electrical rhythms in clock neurons and impairs cycling of neuropeptide pigment dispersing factor, leading to the loss of free-running locomotor rhythms. Together, we conclude that the master clock is not self-sufficient to sustain free-running behavior rhythms but requires additional endogenous inputs to the clock from the extra-clock ultradian brain oscillators.
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Affiliation(s)
- Min Tang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
- PTN Graduate Program, School of Life Sciences, Peking University, Beijing 100871, China
| | - Li-Hui Cao
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing 100069, China
| | - Tian Yang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Si-Xing Ma
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Bi-Yang Jing
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Na Xiao
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Shuang Xu
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Kang-Rui Leng
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Dong Yang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Meng-Tong Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Dong-Gen Luo
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
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Shafer OT, Gutierrez GJ, Li K, Mildenhall A, Spira D, Marty J, Lazar AA, Fernandez MDLP. ---Connectomic analysis of the Drosophila lateral neuron clock cells reveals the synaptic basis of functional pacemaker classes. eLife 2022; 11:79139. [PMID: 35766361 PMCID: PMC9365390 DOI: 10.7554/elife.79139] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/29/2022] [Indexed: 11/23/2022] Open
Abstract
The circadian clock orchestrates daily changes in physiology and behavior to ensure internal temporal order and optimal timing across the day. In animals, a central brain clock coordinates circadian rhythms throughout the body and is characterized by a remarkable robustness that depends on synaptic connections between constituent neurons. The clock neuron network of Drosophila, which shares network motifs with clock networks in the mammalian brain yet is built of many fewer neurons, offers a powerful model for understanding the network properties of circadian timekeeping. Here, we report an assessment of synaptic connectivity within a clock network, focusing on the critical lateral neuron (LN) clock neuron classes within the Janelia hemibrain dataset. Our results reveal that previously identified anatomical and functional subclasses of LNs represent distinct connectomic types. Moreover, we identify a small number of non-clock cell subtypes representing highly synaptically coupled nodes within the clock neuron network. This suggests that neurons lacking molecular timekeeping likely play integral roles within the circadian timekeeping network. To our knowledge, this represents the first comprehensive connectomic analysis of a circadian neuronal network. Most organisms on Earth possess an internal timekeeping system which ensures that bodily processes such as sleep, wakefulness or digestion take place at the right time. These precise daily rhythms are kept in check by a master clock in the brain. There, thousands of neurons – some of which carrying an internal ‘molecular clock’ – connect to each other through structures known as synapses. Exactly how the resulting network is organised to support circadian timekeeping remains unclear. To explore this question, Shafer, Gutierrez et al. focused on fruit flies, as recent efforts have systematically mapped every neuron and synaptic connection in the brain of this model organism. Analysing available data from the hemibrain connectome project at Janelia revealed that that the neurons with the most important timekeeping roles were in fact forming the fewest synapses within the network. In addition, neurons without internal molecular clocks mediated strong synaptic connections between those that did, suggesting that ‘clockless’ cells still play an integral role in circadian timekeeping. With this research, Shafer, Gutierrez et al. provide unexpected insights into the organisation of the master body clock. Better understanding the networks that underpin circadian rhythms will help to grasp how and why these are disrupted in obesity, depression and Alzheimer’s disease.
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Affiliation(s)
- Orie T Shafer
- Advanced Science Research Center, City University of New York, New York, United States
| | - Gabrielle J Gutierrez
- Center for Theoretical Neuroscience, Columbia University, New York City, United States
| | - Kimberly Li
- Department of Neuroscience and Behavior, Barnard College, New York, United States
| | - Amber Mildenhall
- Department of Neuroscience and Behavior, Barnard College, New York, United States
| | - Daphna Spira
- Center for Theoretical Neuroscience, Columbia University, New York City, United States
| | - Jonathan Marty
- Department of Electrical Engineering, Columbia University, New York, United States
| | - Aurel A Lazar
- Department of Electrical Engineering, Columbia University, New York, United States
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7
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Schellinger JN, Sun Q, Pleinis JM, An SW, Hu J, Mercenne G, Titos I, Huang CL, Rothenfluh A, Rodan AR. Chloride oscillation in pacemaker neurons regulates circadian rhythms through a chloride-sensing WNK kinase signaling cascade. Curr Biol 2022; 32:1429-1438.e6. [PMID: 35303418 PMCID: PMC8972083 DOI: 10.1016/j.cub.2022.03.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/02/2021] [Accepted: 03/04/2022] [Indexed: 12/21/2022]
Abstract
Central pacemaker neurons regulate circadian rhythms and undergo diurnal variation in electrical activity in mammals and flies.1,2 Circadian variation in the intracellular chloride concentration of mammalian pacemaker neurons has been proposed to influence the response to GABAergic neurotransmission through GABAA receptor chloride channels.3 However, results have been contradictory,4-9 and a recent study demonstrated circadian variation in pacemaker neuron chloride without an effect on GABA response.10 Therefore, whether and how intracellular chloride regulates circadian rhythms remains controversial. Here, we demonstrate a signaling role for intracellular chloride in the Drosophila small ventral lateral (sLNv) pacemaker neurons. In control flies, intracellular chloride increases in sLNvs over the course of the morning. Chloride transport through sodium-potassium-2-chloride (NKCC) and potassium-chloride (KCC) cotransporters is a major determinant of intracellular chloride concentrations.11Drosophila melanogaster with loss-of-function mutations in the NKCC encoded by Ncc69 have abnormally low intracellular chloride 6 h after lights on, loss of morning anticipation, and a prolonged circadian period. Loss of kcc, which is expected to increase intracellular chloride, suppresses the long-period phenotype of Ncc69 mutant flies. Activation of a chloride-inhibited kinase cascade, consisting of WNK (with no lysine [K]) kinase and its downstream substrate, Fray, is necessary and sufficient to prolong period length. Fray activation of an inwardly rectifying potassium channel, Irk1, is also required for the long-period phenotype. These results indicate that the NKCC-dependent rise in intracellular chloride in Drosophila sLNv pacemakers restrains WNK-Fray signaling and overactivation of an inwardly rectifying potassium channel to maintain normal circadian period length.
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Affiliation(s)
- Jeffrey N Schellinger
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Qifei Sun
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern, Dallas, TX 75390, USA
| | - John M Pleinis
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Sung-Wan An
- Department of Internal Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Jianrui Hu
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Gaëlle Mercenne
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Iris Titos
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Chou-Long Huang
- Department of Internal Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Adrian Rothenfluh
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA; Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT 84108, USA; Department of Neurobiology, University of Utah, Salt Lake City, UT 84112, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Aylin R Rodan
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA; Department of Internal Medicine, Division of Nephrology and Hypertension, University of Utah, Salt Lake City, UT 84132, USA; Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT 84148, USA.
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8
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Ramakrishnan A, Sheeba V. Gap junction protein Innexin2 modulates the period of free-running rhythms in Drosophila melanogaster. iScience 2021; 24:103011. [PMID: 34522854 PMCID: PMC8426565 DOI: 10.1016/j.isci.2021.103011] [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: 06/16/2021] [Revised: 07/13/2021] [Accepted: 08/17/2021] [Indexed: 10/25/2022] Open
Abstract
A neuronal circuit of ∼150 neurons modulates rhythmic activity-rest behavior of Drosophila melanogaster. While it is known that coherent ∼24-hr rhythms in locomotion are brought about when 7 distinct neuronal clusters function as a network due to chemical communication amongst them, there are no reports of communication via electrical synapses made up of gap junctions. Here, we report that gap junction proteins, Innexins play crucial roles in determining the intrinsic period of activity-rest rhythms in flies. We show the presence of Innexin2 in the ventral lateral neurons, wherein RNAi-based knockdown of its expression slows down the speed of activity-rest rhythm along with alterations in the oscillation of a core-clock protein PERIOD and the output molecule pigment dispersing factor. Specifically disrupting the channel-forming ability of Innexin2 causes period lengthening, suggesting that Innexin2 may function as hemichannels or gap junctions in the clock circuit.
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Affiliation(s)
- Aishwarya Ramakrishnan
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
| | - Vasu Sheeba
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka 560064, India
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9
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Baluška F, Reber AS. CBC-Clock Theory of Life - Integration of cellular circadian clocks and cellular sentience is essential for cognitive basis of life. Bioessays 2021; 43:e2100121. [PMID: 34382225 DOI: 10.1002/bies.202100121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/16/2021] [Accepted: 07/19/2021] [Indexed: 12/20/2022]
Abstract
Cellular circadian clocks represent ancient anticipatory systems which co-evolved with the first cells to safeguard their survival. Cyanobacteria represent one of the most ancient cells, having essentially invented photosynthesis together with redox-based cellular circadian clocks some 2.7 billion years ago. Bioelectricity phenomena, based on redox homeostasis associated electron transfers in membranes and within protein complexes inserted in excitable membranes, play important roles, not only in the cellular circadian clocks and in anesthetics-sensitive cellular sentience (awareness of environment), but also in the coupling of single cells into tissues and organs of unitary multicellular organisms. This integration of cellular circadian clocks with cellular basis of sentience is an essential feature of the cognitive CBC-Clock basis of cellular life.
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Affiliation(s)
- František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany
| | - Arthur S Reber
- Department of Psychology, University of British Columbia, Vancouver, Canada
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10
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Costa R. Frontiers in Chronobiology: Endogenous Clocks at the Core of Signaling Pathways in Physiology. Front Physiol 2021; 12:684745. [PMID: 34093241 PMCID: PMC8173170 DOI: 10.3389/fphys.2021.684745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 04/14/2021] [Indexed: 11/29/2022] Open
Affiliation(s)
- Rodolfo Costa
- Department of Biology, University of Padova, Italian National Research Council (CNR) Institute of Neuroscience, Padova, Italy
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11
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Cavieres-Lepe J, Ewer J. Reciprocal Relationship Between Calcium Signaling and Circadian Clocks: Implications for Calcium Homeostasis, Clock Function, and Therapeutics. Front Mol Neurosci 2021; 14:666673. [PMID: 34045944 PMCID: PMC8144308 DOI: 10.3389/fnmol.2021.666673] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/09/2021] [Indexed: 12/03/2022] Open
Abstract
In animals, circadian clocks impose a daily rhythmicity to many behaviors and physiological processes. At the molecular level, circadian rhythms are driven by intracellular transcriptional/translational feedback loops (TTFL). Interestingly, emerging evidence indicates that they can also be modulated by multiple signaling pathways. Among these, Ca2+ signaling plays a key role in regulating the molecular rhythms of clock genes and of the resulting circadian behavior. In addition, the application of in vivo imaging approaches has revealed that Ca2+ is fundamental to the synchronization of the neuronal networks that make up circadian pacemakers. Conversely, the activity of circadian clocks may influence Ca2+ signaling. For instance, several genes that encode Ca2+ channels and Ca2+-binding proteins display a rhythmic expression, and a disruption of this cycling affects circadian function, underscoring their reciprocal relationship. Here, we review recent advances in our understanding of how Ca2+ signaling both modulates and is modulated by circadian clocks, focusing on the regulatory mechanisms described in Drosophila and mice. In particular, we examine findings related to the oscillations in intracellular Ca2+ levels in circadian pacemakers and how they are regulated by canonical clock genes, neuropeptides, and light stimuli. In addition, we discuss how Ca2+ rhythms and their associated signaling pathways modulate clock gene expression at the transcriptional and post-translational levels. We also review evidence based on transcriptomic analyzes that suggests that mammalian Ca2+ channels and transporters (e.g., ryanodine receptor, ip3r, serca, L- and T-type Ca2+ channels) as well as Ca2+-binding proteins (e.g., camk, cask, and calcineurin) show rhythmic expression in the central brain clock and in peripheral tissues such as the heart and skeletal muscles. Finally, we discuss how the discovery that Ca2+ signaling is regulated by the circadian clock could influence the efficacy of pharmacotherapy and the outcomes of clinical interventions.
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Affiliation(s)
- Javier Cavieres-Lepe
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile.,Programa de Doctorado en Ciencias, Mención Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - John Ewer
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile
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12
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Coupling Neuropeptide Levels to Structural Plasticity in Drosophila Clock Neurons. Curr Biol 2020; 30:3154-3166.e4. [PMID: 32619484 DOI: 10.1016/j.cub.2020.06.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/05/2020] [Accepted: 06/02/2020] [Indexed: 12/24/2022]
Abstract
We have previously reported that pigment dispersing factor (PDF) neurons, which are essential in the control of rest-activity cycles in Drosophila, undergo circadian remodeling of their axonal projections, a phenomenon called circadian structural plasticity. Axonal arborizations display higher complexity during the day and become simpler at night, and this remodeling involves changes in the degree of connectivity. This phenomenon depends on the clock present within the ventrolateral neurons (LNvs) as well as in glia. In this work, we characterize in detail the contribution of the PDF neuropeptide to structural plasticity at different times across the day. Using diverse genetic strategies to temporally restrict its downregulation, we demonstrate that even subtle alterations to PDF cycling at the dorsal protocerebrum correlate with impaired remodeling, underscoring its relevance for the characteristic morning spread; PDF released from the small LNvs (sLNvs) and the large LNvs (lLNvs) contribute to the process. Moreover, forced depolarization recruits activity-dependent mechanisms to mediate growth only at night, overcoming the restriction imposed by the clock on membrane excitability. Interestingly, the active process of terminal remodeling requires PDF receptor (PDFR) signaling acting locally through the cyclic-nucleotide-gated channel ion channel subunit A (CNGA). Thus, clock-dependent PDF signaling shapes the connectivity of these essential clock neurons on daily basis.
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13
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Ogueta M, Hardie RC, Stanewsky R. Light Sampling via Throttled Visual Phototransduction Robustly Synchronizes the Drosophila Circadian Clock. Curr Biol 2020; 30:2551-2563.e3. [PMID: 32502413 DOI: 10.1016/j.cub.2020.04.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/07/2020] [Accepted: 04/24/2020] [Indexed: 01/19/2023]
Abstract
The daily changes of light and dark exemplify a prominent cue for the synchronization of circadian clocks with the environment. The match between external and internal time is crucial for the fitness of organisms, and desynchronization has been linked to numerous physical and mental health problems. Organisms therefore developed complex and not fully understood mechanisms to synchronize their circadian clock to light. In mammals and in Drosophila, both the visual system and non-image-forming photoreceptors contribute to circadian clock resetting. In Drosophila, light-dependent degradation of the clock protein TIMELESS by the blue light photoreceptor Cryptochrome is considered the main mechanism for clock synchronization, although the visual system also contributes. To better understand the visual system contribution, we generated a genetic variant exhibiting extremely slow phototransduction kinetics, yet normal sensitivity. In this variant, the visual system is able to contribute its full share to circadian clock entrainment, both with regard to behavioral and molecular light synchronization. This function depends on an alternative phospholipase C-β enzyme, encoded by PLC21C, presumably playing a dedicated role in clock resetting. We show that this pathway requires the ubiquitin ligase CULLIN-3, possibly mediating CRY-independent degradation of TIMELESS during light:dark cycles. Our results suggest that the PLC21C-mediated contribution to circadian clock entrainment operates on a drastically slower timescale compared with fast, norpA-dependent visual phototransduction. Our findings are therefore consistent with the general idea that the visual system samples light over prolonged periods of time (h) in order to reliably synchronize their internal clocks with the external time.
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Affiliation(s)
- Maite Ogueta
- Institute of Neuro and Behavioral Biology, Westfälische Wilhelms University, 48149 Münster, Germany
| | - Roger C Hardie
- Department of Physiology, Development, and Neuroscience, Cambridge University, Cambridge CB2 3EG, UK
| | - Ralf Stanewsky
- Institute of Neuro and Behavioral Biology, Westfälische Wilhelms University, 48149 Münster, Germany.
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14
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Smith P, Buhl E, Tsaneva-Atanasova K, Hodge JJL. Shaw and Shal voltage-gated potassium channels mediate circadian changes in Drosophila clock neuron excitability. J Physiol 2019; 597:5707-5722. [PMID: 31612994 DOI: 10.1113/jp278826] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 10/03/2019] [Indexed: 01/08/2023] Open
Abstract
As in mammals, Drosophila circadian clock neurons display rhythms of activity with higher action potential firing rates and more positive resting membrane potentials during the day. This rhythmic excitability has been widely observed but, critically, its regulation remains unresolved. We have characterized and modelled the changes underlying these electrical activity rhythms in the lateral ventral clock neurons (LNvs). We show that currents mediated by the voltage-gated potassium channels Shaw (Kv3) and Shal (Kv4) oscillate in a circadian manner. Disruption of these channels, by expression of dominant negative (DN) subunits, leads to changes in circadian locomotor activity and shortens lifespan. LNv whole-cell recordings then show that changes in Shaw and Shal currents drive changes in action potential firing rate and that these rhythms are abolished when the circadian molecular clock is stopped. A whole-cell biophysical model using Hodgkin-Huxley equations can recapitulate these changes in electrical activity. Based on this model and by using dynamic clamp to manipulate clock neurons directly, we can rescue the pharmacological block of Shaw and Shal, restore the firing rhythm, and thus demonstrate the critical importance of Shaw and Shal. Together, these findings point to a key role for Shaw and Shal in controlling circadian firing of clock neurons and show that changes in clock neuron currents can account for this. Moreover, with dynamic clamp we can switch the LNvs between morning-like and evening-like states of electrical activity. We conclude that changes in Shaw and Shal underlie the daily oscillation in LNv firing rate.
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Affiliation(s)
- Philip Smith
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Edgar Buhl
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Krasimira Tsaneva-Atanasova
- Department of Mathematics and Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - James J L Hodge
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, BS8 1TD, UK
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15
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Xu F, Kula-Eversole E, Iwanaszko M, Lim C, Allada R. Ataxin2 functions via CrebA to mediate Huntingtin toxicity in circadian clock neurons. PLoS Genet 2019; 15:e1008356. [PMID: 31593562 PMCID: PMC6782096 DOI: 10.1371/journal.pgen.1008356] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 08/07/2019] [Indexed: 12/12/2022] Open
Abstract
Disrupted circadian rhythms is a prominent and early feature of neurodegenerative diseases including Huntington’s disease (HD). In HD patients and animal models, striatal and hypothalamic neurons expressing molecular circadian clocks are targets of mutant Huntingtin (mHtt) pathogenicity. Yet how mHtt disrupts circadian rhythms remains unclear. In a genetic screen for modifiers of mHtt effects on circadian behavior in Drosophila, we discovered a role for the neurodegenerative disease gene Ataxin2 (Atx2). Genetic manipulations of Atx2 modify the impact of mHtt on circadian behavior as well as mHtt aggregation and demonstrate a role for Atx2 in promoting mHtt aggregation as well as mHtt-mediated neuronal dysfunction. RNAi knockdown of the Fragile X mental retardation gene, dfmr1, an Atx2 partner, also partially suppresses mHtt effects and Atx2 effects depend on dfmr1. Atx2 knockdown reduces the cAMP response binding protein A (CrebA) transcript at dawn. CrebA transcript level shows a prominent diurnal regulation in clock neurons. Loss of CrebA also partially suppresses mHtt effects on behavior and cell loss and restoration of CrebA can suppress Atx2 effects. Our results indicate a prominent role of Atx2 in mediating mHtt pathology, specifically via its regulation of CrebA, defining a novel molecular pathway in HD pathogenesis. Circadian clocks evolved to anticipate 24 h environmental rhythms driven by the earth’s daily rotation and regulate nearly all aspects of behavior, physiology and the genome. Disruptions of the circadian clock have been associated with a wide range of human diseases, including neurodegenerative diseases such as Huntington’s disease (HD). Using an HD animal model in which a mutant Huntingtin (mHtt) protein is expressed, we identify a role for the RNA binding protein and neurodegenerative disease gene Ataxin-2 (Atx2) in mediating mHtt effects on circadian behavioral rhythms. Using transcriptomics, we identify the transcription factor CrebA as a potential target of both Atx2 and the circadian clock. Finally, we demonstrate a role for CrebA in mediating mHtt effects on circadian behavior, defining a novel Atx2-CrebA pathway in a neurodegenerative disease model. These studies define the molecular mechanisms by which mHtt can disrupt circadian rhythms identifying potential novel therapeutic targets for this uniformly fatal disease.
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Affiliation(s)
- Fangke Xu
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
| | - Elzbieta Kula-Eversole
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
| | - Marta Iwanaszko
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Chunghun Lim
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
| | - Ravi Allada
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
- * E-mail:
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16
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Harbison ST, Kumar S, Huang W, McCoy LJ, Smith KR, Mackay TFC. Genome-Wide Association Study of Circadian Behavior in Drosophila melanogaster. Behav Genet 2018; 49:60-82. [PMID: 30341464 PMCID: PMC6326971 DOI: 10.1007/s10519-018-9932-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 10/04/2018] [Indexed: 12/31/2022]
Abstract
Circadian rhythms influence physiological processes from sleep–wake cycles to body temperature and are controlled by highly conserved cycling molecules. Although the mechanistic basis of the circadian clock has been known for decades, the extent to which circadian rhythms vary in nature and the underlying genetic basis for that variation is not well understood. We measured circadian period (Ʈ) and rhythmicity index in the Drosophila Genetic Reference Panel (DGRP) and observed extensive genetic variation in both. Seven DGRP lines had sexually dimorphic arrhythmicity and one line had an exceptionally long Ʈ. Genome-wide analyses identified 584 polymorphisms in 268 genes. We observed differences among transcripts for nine genes predicted to interact among themselves and canonical clock genes in the long period line and a control. Mutations/RNAi knockdown targeting these genes also affected circadian behavior. Our observations reveal that complex genetic interactions influence high levels of variation in circadian phenotypes.
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Affiliation(s)
- Susan T Harbison
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA. .,Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA. .,Laboratory of Systems Genetics, National Heart Lung and Blood Institute, Building 10, Room 7D13, 10 Center Drive, Bethesda, MD, 20892-1640, USA.
| | - Shailesh Kumar
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Wen Huang
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Genetics Program and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA.,Department of Animal Science, Michigan State University, East Lansing, MI, USA
| | - Lenovia J McCoy
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Kirklin R Smith
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Trudy F C Mackay
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Genetics Program and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA.,Center for Human Genetics and Department of Genetics and Biochemistry, Clemson University, 114 Gregor Mendel Circle, Greenwood, SC, 29646, USA
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17
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Belle MDC, Allen CN. The circadian clock: A tale of genetic-electrical interplay and synaptic integration. CURRENT OPINION IN PHYSIOLOGY 2018; 5:75-79. [PMID: 31011692 DOI: 10.1016/j.cophys.2018.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Pioneering work in Drosophila uncovered the building blocks of the molecular clock, consisting of transcription-translation feedback loops (TTFLs). Subsequent experimental work demonstrated that the mammalian TTFL is localized in cells and tissues throughout the brain and body. Further research established that neuronal activity forms an essential aspect of clock function. However, how the membrane electrical activity of clock neurons of the suprachiasmatic nucleus collaborate with the TTFL to drive circadian behaviors remains mostly unknown. Intercellular communication synchronizes the individual circadian oscillators to produce a precise and coherent circadian output. Here, we briefly review significant research that is increasing our understanding of the critical interactions between the TTFL and neuronal and glial activity in the generation of circadian timing signals.
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Affiliation(s)
- Mino D C Belle
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Exeter, EX4 4PS, UK.
| | - Charles N Allen
- Oregon Institute of Occupational Health Sciences and Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239, USA.
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18
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Affiliation(s)
- Albano C Meli
- PhyMedExp, INSERM, CNRS, University of Montpellier, CHU Arnaud de Villeneuve, 34295 Montpellier Cedex 5, France
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19
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Calcium and cAMP directly modulate the speed of the Drosophila circadian clock. PLoS Genet 2018; 14:e1007433. [PMID: 29879123 PMCID: PMC6007936 DOI: 10.1371/journal.pgen.1007433] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/19/2018] [Accepted: 05/18/2018] [Indexed: 01/08/2023] Open
Abstract
Circadian clocks impose daily periodicities to animal behavior and physiology. At their core, circadian rhythms are produced by intracellular transcriptional/translational feedback loops (TTFL). TTFLs may be altered by extracellular signals whose actions are mediated intracellularly by calcium and cAMP. In mammals these messengers act directly on TTFLs via the calcium/cAMP-dependent transcription factor, CREB. In the fruit fly, Drosophila melanogaster, calcium and cAMP also regulate the periodicity of circadian locomotor activity rhythmicity, but whether this is due to direct actions on the TTFLs themselves or are a consequence of changes induced to the complex interrelationship between different classes of central pacemaker neurons is unclear. Here we investigated this question focusing on the peripheral clock housed in the non-neuronal prothoracic gland (PG), which, together with the central pacemaker in the brain, controls the timing of adult emergence. We show that genetic manipulations that increased and decreased the levels of calcium and cAMP in the PG caused, respectively, a shortening and a lengthening of the periodicity of emergence. Importantly, knockdown of CREB in the PG caused an arrhythmic pattern of eclosion. Interestingly, the same manipulations directed at central pacemaker neurons caused arrhythmicity of eclosion and of adult locomotor activity, suggesting a common mechanism. Our results reveal that the calcium and cAMP pathways can alter the functioning of the clock itself. In the PG, these messengers, acting as outputs of the clock or as second messengers for stimuli external to the PG, could also contribute to the circadian gating of adult emergence. Circadian clocks impose daily periodicities to animal behavior and physiology. At their core, circadian rhythms are produced by intracellular transcriptional/translational feedback loops (TTFL). TTFLs may be altered by extracellular signals whose actions are mediated intracellularly by calcium and cAMP. In Drosophila, calcium and cAMP levels affect the periodicity of Drosophila circadian rhythms, but whether this is due to direct actions on the TTFLs themselves or is a consequence of changes induced to the complex interrelationship between different classes of central pacemaker neurons is unclear. Here we used the non-neuronal circadian clock located in the prothoracic gland (PG) to show that these messengers affect the speed of the circadian clock that controls the timing of adult emergence and suggest that these actions are mediated by CREB. Importantly, since calcium and cAMP are also output signals of the clock, they may contribute to the mechanism that imposes a circadian gating to the timing of adult emergence.
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20
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Belle MDC, Diekman CO. Neuronal oscillations on an ultra-slow timescale: daily rhythms in electrical activity and gene expression in the mammalian master circadian clockwork. Eur J Neurosci 2018; 48:2696-2717. [PMID: 29396876 DOI: 10.1111/ejn.13856] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/16/2018] [Accepted: 01/28/2018] [Indexed: 12/17/2022]
Abstract
Neuronal oscillations of the brain, such as those observed in the cortices and hippocampi of behaving animals and humans, span across wide frequency bands, from slow delta waves (0.1 Hz) to ultra-fast ripples (600 Hz). Here, we focus on ultra-slow neuronal oscillators in the hypothalamic suprachiasmatic nuclei (SCN), the master daily clock that operates on interlocking transcription-translation feedback loops to produce circadian rhythms in clock gene expression with a period of near 24 h (< 0.001 Hz). This intracellular molecular clock interacts with the cell's membrane through poorly understood mechanisms to drive the daily pattern in the electrical excitability of SCN neurons, exhibiting an up-state during the day and a down-state at night. In turn, the membrane activity feeds back to regulate the oscillatory activity of clock gene programs. In this review, we emphasise the circadian processes that drive daily electrical oscillations in SCN neurons, and highlight how mathematical modelling contributes to our increasing understanding of circadian rhythm generation, synchronisation and communication within this hypothalamic region and across other brain circuits.
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Affiliation(s)
- Mino D C Belle
- Institute of Clinical and Biomedical Sciences, University of Exeter Medical School, University of Exeter, Exeter, EX4 4PS, UK
| | - Casey O Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, NJ, USA.,Institute for Brain and Neuroscience Research, New Jersey Institute of Technology, Newark, NJ, USA
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21
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Hughes ME, Abruzzi KC, Allada R, Anafi R, Arpat AB, Asher G, Baldi P, de Bekker C, Bell-Pedersen D, Blau J, Brown S, Ceriani MF, Chen Z, Chiu JC, Cox J, Crowell AM, DeBruyne JP, Dijk DJ, DiTacchio L, Doyle FJ, Duffield GE, Dunlap JC, Eckel-Mahan K, Esser KA, FitzGerald GA, Forger DB, Francey LJ, Fu YH, Gachon F, Gatfield D, de Goede P, Golden SS, Green C, Harer J, Harmer S, Haspel J, Hastings MH, Herzel H, Herzog ED, Hoffmann C, Hong C, Hughey JJ, Hurley JM, de la Iglesia HO, Johnson C, Kay SA, Koike N, Kornacker K, Kramer A, Lamia K, Leise T, Lewis SA, Li J, Li X, Liu AC, Loros JJ, Martino TA, Menet JS, Merrow M, Millar AJ, Mockler T, Naef F, Nagoshi E, Nitabach MN, Olmedo M, Nusinow DA, Ptáček LJ, Rand D, Reddy AB, Robles MS, Roenneberg T, Rosbash M, Ruben MD, Rund SSC, Sancar A, Sassone-Corsi P, Sehgal A, Sherrill-Mix S, Skene DJ, Storch KF, Takahashi JS, Ueda HR, Wang H, Weitz C, Westermark PO, Wijnen H, Xu Y, Wu G, Yoo SH, Young M, Zhang EE, Zielinski T, Hogenesch JB. Guidelines for Genome-Scale Analysis of Biological Rhythms. J Biol Rhythms 2017; 32:380-393. [PMID: 29098954 PMCID: PMC5692188 DOI: 10.1177/0748730417728663] [Citation(s) in RCA: 173] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Genome biology approaches have made enormous contributions to our understanding of biological rhythms, particularly in identifying outputs of the clock, including RNAs, proteins, and metabolites, whose abundance oscillates throughout the day. These methods hold significant promise for future discovery, particularly when combined with computational modeling. However, genome-scale experiments are costly and laborious, yielding “big data” that are conceptually and statistically difficult to analyze. There is no obvious consensus regarding design or analysis. Here we discuss the relevant technical considerations to generate reproducible, statistically sound, and broadly useful genome-scale data. Rather than suggest a set of rigid rules, we aim to codify principles by which investigators, reviewers, and readers of the primary literature can evaluate the suitability of different experimental designs for measuring different aspects of biological rhythms. We introduce CircaInSilico, a web-based application for generating synthetic genome biology data to benchmark statistical methods for studying biological rhythms. Finally, we discuss several unmet analytical needs, including applications to clinical medicine, and suggest productive avenues to address them.
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Affiliation(s)
- Michael E Hughes
- 1 Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Katherine C Abruzzi
- 2 Department of Biology and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts, USA
| | - Ravi Allada
- 3 Department of Neurobiology, Northwestern University, Evanston, Illinois, USA
| | - Ron Anafi
- 4 Division of Sleep Medicine, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA
| | - Alaaddin Bulak Arpat
- 5 Center for Integrative Genomics, Génopode, University of Lausanne, Lausanne, Switzerland.,6 Vital-IT, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Gad Asher
- 7 Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Pierre Baldi
- 8 Institute for Genomics and Bioinformatics, University of California, Irvine, USA
| | | | | | - Justin Blau
- 11 Department of Biology, New York University, New York, USA
| | - Steve Brown
- 12 Institute of Pharmacology and Toxicology, University of Zürich, Switzerland
| | - M Fernanda Ceriani
- 13 Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Zheng Chen
- 14 Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, USA
| | - Joanna C Chiu
- 15 Department of Entomology and Nematology, University of California, Davis, USA
| | - Juergen Cox
- 16 Computational Systems Biochemistry, Max-Planck Institute of Biochemistry, Martinsried, Germany
| | - Alexander M Crowell
- 17 Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Jason P DeBruyne
- 18 Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, USA
| | - Derk-Jan Dijk
- 19 Surrey Sleep Research Centre, University of Surrey, Guildford, UK
| | - Luciano DiTacchio
- 20 The University of Kansas Medical Center, University of Kansas, Kansas City, USA
| | - Francis J Doyle
- 21 John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, Massachusetts, USA
| | - Giles E Duffield
- 22 Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Jay C Dunlap
- 17 Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Kristin Eckel-Mahan
- 23 Institute of Molecular Medicine, McGovern Medical School, UT Health Houston, Houston, Texas, USA
| | - Karyn A Esser
- 24 Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, USA
| | - Garret A FitzGerald
- 25 Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA
| | - Daniel B Forger
- 26 Department of Mathematics, University of Michigan, Ann Arbor, USA
| | - Lauren J Francey
- 27 Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Ying-Hui Fu
- 28 Kavli Institute for Fundamental Neuroscience, Weill Institute of Neuroscience, Department of Neurology, University of California, San Francisco, USA
| | - Frédéric Gachon
- 29 Department of Diabetes and Circadian Rhythms, Nestlé Institute of Health Sciences, Lausanne, Switzerland
| | - David Gatfield
- 5 Center for Integrative Genomics, Génopode, University of Lausanne, Lausanne, Switzerland
| | - Paul de Goede
- 30 Department of Endocrinology & Metabolism, Academic Medical Center, Amsterdam, the Netherlands
| | - Susan S Golden
- 31 Center for Circadian Biology and Division of Biological Sciences, University of California, San Diego, La Jolla, USA
| | - Carla Green
- 32 Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, USA
| | - John Harer
- 33 Department of Mathematics, Duke University, Durham, North Carolina, USA
| | - Stacey Harmer
- 34 Department of Plant Biology, University of California, Davis, USA
| | - Jeff Haspel
- 1 Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael H Hastings
- 35 Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Hanspeter Herzel
- 36 Institute for Theoretical Biology, Charité-Universitätsmedizin Berlin, Germany
| | - Erik D Herzog
- 37 Department of Biology, Washington University in St. Louis, Missouri, USA
| | - Christy Hoffmann
- 1 Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Christian Hong
- 27 Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Jacob J Hughey
- 38 Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jennifer M Hurley
- 39 Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
| | | | - Carl Johnson
- 41 Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Steve A Kay
- 42 Department of Cell and Molecular Biology, The Scripps Research Institute, University of California, San Diego, La Jolla, USA
| | - Nobuya Koike
- 43 Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Japan
| | - Karl Kornacker
- 44 Division of Sensory Biophysics, The Ohio State University, Columbus, USA
| | - Achim Kramer
- 45 Laboratory of Chronobiology, Charité Universitätsmedizin Berlin, Germany
| | - Katja Lamia
- 46 Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Tanya Leise
- 47 Department of Mathematics and Statistics, Amherst College, Amherst, Massachusetts, USA
| | - Scott A Lewis
- 1 Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jiajia Li
- 1 Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,48 Department of Biology, University of Missouri-St. Louis, USA
| | - Xiaodong Li
- 49 Department of Cell Biology, College of Life Sciences at Wuhan University, China
| | - Andrew C Liu
- 50 Department of Biological Sciences, University of Memphis, Tennessee, USA
| | - Jennifer J Loros
- 51 Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Tami A Martino
- 52 Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Jerome S Menet
- 10 Department of Biology, Texas A&M University, College Station, USA
| | - Martha Merrow
- 53 Institute of Medical Psychology, Faculty of Medicine, LMU Munich, Germany
| | - Andrew J Millar
- 54 SynthSys and School of Biological Sciences, University of Edinburgh, UK
| | - Todd Mockler
- 55 Donald Danforth Plant Science Center, St. Louis, Missouri, USA
| | - Felix Naef
- 56 The Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Switzerland
| | - Emi Nagoshi
- 57 Department of Genetics and Evolution, University of Geneva, Switzerland
| | - Michael N Nitabach
- 58 Department of Cellular and Molecular Physiology, Department of Genetics, Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut, USA
| | - Maria Olmedo
- 59 Department of Genetics, University of Seville, Spain
| | - Dmitri A Nusinow
- 55 Donald Danforth Plant Science Center, St. Louis, Missouri, USA
| | - Louis J Ptáček
- 60 Department of Neurology, University of California, San Francisco, USA
| | - David Rand
- 61 Warwick Systems Biology and Mathematics Institute, University of Warwick, Conventry, UK
| | - Akhilesh B Reddy
- 62 The Francis Crick Institute, London, UK, and UCL Institute of Neurology, Queen Square, London, UK
| | - Maria S Robles
- 53 Institute of Medical Psychology, Faculty of Medicine, LMU Munich, Germany
| | - Till Roenneberg
- 53 Institute of Medical Psychology, Faculty of Medicine, LMU Munich, Germany
| | - Michael Rosbash
- 2 Department of Biology and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts, USA
| | - Marc D Ruben
- 27 Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Samuel S C Rund
- 63 Centre for Immunity, Infection and Evolution, University of Edinburgh, UK
| | - Aziz Sancar
- 64 Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, USA
| | - Paolo Sassone-Corsi
- 65 Department of Biological Chemistry, Center for Epigenetics and Metabolism, University of California, Irvine, USA
| | - Amita Sehgal
- 66 Howard Hughes Medical Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA
| | - Scott Sherrill-Mix
- 67 Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA
| | - Debra J Skene
- 68 Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Kai-Florian Storch
- 69 Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, Canada
| | - Joseph S Takahashi
- 70 Howard Hughes Medical Institute, Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, USA
| | - Hiroki R Ueda
- 71 Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan Laboratory for Synthetic Biology, RIKEN Quantitative Biology Center, Osaka, Japan
| | - Han Wang
- 72 Center for Circadian Clocks, Soochow University, Suzhou, Jiangsu, China
| | - Charles Weitz
- 73 Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Pål O Westermark
- 74 Institute of Genetics and Biometry, Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany
| | - Herman Wijnen
- 75 Biological Sciences and Institute for Life Sciences, University of Southampton, UK
| | - Ying Xu
- 76 Cam-Su GRC, Soochow University, Suzhou, China
| | - Gang Wu
- 27 Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Seung-Hee Yoo
- 14 Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, USA
| | - Michael Young
- 77 Laboratory of Genetics, Rockefeller University, New York, New York, USA
| | | | - Tomasz Zielinski
- 54 SynthSys and School of Biological Sciences, University of Edinburgh, UK
| | - John B Hogenesch
- 27 Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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22
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Allen CN, Nitabach MN, Colwell CS. Membrane Currents, Gene Expression, and Circadian Clocks. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a027714. [PMID: 28246182 DOI: 10.1101/cshperspect.a027714] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Neuronal circadian oscillators in the mammalian and Drosophila brain express a circadian clock comprised of interlocking gene transcription feedback loops. The genetic clock regulates the membrane electrical activity by poorly understood signaling pathways to generate a circadian pattern of action potential firing. During the day, Na+ channels contribute an excitatory drive for the spontaneous activity of circadian clock neurons. Multiple types of K+ channels regulate the action potential firing pattern and the nightly reduction in neuronal activity. The membrane electrical activity possibly signaling by changes in intracellular Ca2+ and cyclic adenosine monophosphate (cAMP) regulates the activity of the gene clock. A decline in the signaling pathways that link the gene clock and neural activity during aging and disease may weaken the circadian output and generate significant impacts on human health.
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Affiliation(s)
- Charles N Allen
- Oregon Institute of Occupational Health Sciences and Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239
| | - Michael N Nitabach
- Department of Cellular and Molecular Physiology and Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520
| | - Christopher S Colwell
- Department of Psychiatry & Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California 90024
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23
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Quasimodo mediates daily and acute light effects on Drosophila clock neuron excitability. Proc Natl Acad Sci U S A 2016; 113:13486-13491. [PMID: 27821737 DOI: 10.1073/pnas.1606547113] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have characterized a light-input pathway regulating Drosophila clock neuron excitability. The molecular clock drives rhythmic electrical excitability of clock neurons, and we show that the recently discovered light-input factor Quasimodo (Qsm) regulates this variation, presumably via an Na+, K+, Cl- cotransporter (NKCC) and the Shaw K+ channel (dKV3.1). Because of light-dependent degradation of the clock protein Timeless (Tim), constant illumination (LL) leads to a breakdown of molecular and behavioral rhythms. Both overexpression (OX) and knockdown (RNAi) of qsm, NKCC, or Shaw led to robust LL rhythmicity. Whole-cell recordings of the large ventral lateral neurons (l-LNv) showed that altering Qsm levels reduced the daily variation in neuronal activity: qsmOX led to a constitutive less active, night-like state, and qsmRNAi led to a more active, day-like state. Qsm also affected daily changes in K+ currents and the GABA reversal potential, suggesting a role in modifying membrane currents and GABA responses in a daily fashion, potentially modulating light arousal and input to the clock. When directly challenged with blue light, wild-type l-LNvs responded with increased firing at night and no net response during the day, whereas altering Qsm, NKKC, or Shaw levels abolished these day/night differences. Finally, coexpression of ShawOX and NKCCRNAi in a qsm mutant background restored LL-induced behavioral arrhythmicity and wild-type neuronal activity patterns, suggesting that the three genes operate in the same pathway. We propose that Qsm affects both daily and acute light effects in l-LNvs probably acting on Shaw and NKCC.
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24
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Stengl M, Arendt A. Peptidergic circadian clock circuits in the Madeira cockroach. Curr Opin Neurobiol 2016; 41:44-52. [PMID: 27575405 DOI: 10.1016/j.conb.2016.07.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 07/16/2016] [Accepted: 07/20/2016] [Indexed: 01/29/2023]
Abstract
Circadian clocks control physiology and behavior of organisms in synchrony with external light dark cycles in changing photoperiods. The Madeira cockroach Rhyparobia maderae was the first model organism in which an endogenous circadian clock in the brain was identified. About 240 neurons constitute the cockroach circadian pacemaker network in the accessory medulla. The expression of high concentrations of neuropeptides, among them the most prominent circadian coupling factor pigment-dispersing factor, as well as their ability to generate endogenous ultradian and circadian rhythms in electrical activity and clock gene expression distinguish these pacemaker neurons. We assume that entrainment to light-dark cycles and the control of 24h rest-activity rhythms is achieved via peptidergic circuits forming autoreceptive labeled lines.
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Affiliation(s)
- Monika Stengl
- University of Kassel, Biology, Animal Physiology, Heinrich Plett Str. 40, 34132 Kassel, Germany.
| | - Andreas Arendt
- University of Kassel, Biology, Animal Physiology, Heinrich Plett Str. 40, 34132 Kassel, Germany
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25
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Eck S, Helfrich-Förster C, Rieger D. The Timed Depolarization of Morning and Evening Oscillators Phase Shifts the Circadian Clock of Drosophila. J Biol Rhythms 2016; 31:428-42. [PMID: 27269519 DOI: 10.1177/0748730416651363] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Phase response curves (PRCs) for light or temperature stimuli have been shown to be most valuable in understanding how circadian clocks are entrained to daily environmental cycles. Nowadays, PRC experiments in which clock neurons are manipulated in a temporally restricted manner by thermogenetic or optogenetic tools are also useful to comprehend clock network properties. Here, we temporally depolarized specific clock neurons of Drosophila melanogaster by activating temperature-sensitive dTrpA1 channels to unravel their role in phase shifting the flies' activity rhythm. The depolarization of all clock neurons caused a PRC resembling the flies' light PRC, with strong phase delays in the first half of the subjective night and modest phase advances in its second half. However, the activation of the flies' pigment-dispersing factor (PDF)-positive morning (M) neurons (s-LNvs) only induced phase advances, and these reached into the subjective day, where the light PRC has its dead zone. This indicates that the M neurons are very potent in accelerating the clock, which is in line with previous observations. In contrast, the evening (E) neurons together with the PDF-positive l-LNvs appear to mediate phase delays. Most interestingly, the molecular clock (Period protein cycling) of the depolarized clock neurons was shifted in parallel to the behavior, and this shift was already visible within the first cycle after the temperature pulse. We identified cAMP response element binding protein B (CREB) as a putative link between membrane depolarization and the molecular clock.
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Affiliation(s)
- Saskia Eck
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Germany
| | | | - Dirk Rieger
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Germany
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26
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Petsakou A, Sapsis TP, Blau J. Circadian Rhythms in Rho1 Activity Regulate Neuronal Plasticity and Network Hierarchy. Cell 2015; 162:823-35. [PMID: 26234154 DOI: 10.1016/j.cell.2015.07.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 03/19/2015] [Accepted: 06/13/2015] [Indexed: 01/02/2023]
Abstract
Neuronal plasticity helps animals learn from their environment. However, it is challenging to link specific changes in defined neurons to altered behavior. Here, we focus on circadian rhythms in the structure of the principal s-LNv clock neurons in Drosophila. By quantifying neuronal architecture, we observed that s-LNv structural plasticity changes the amount of axonal material in addition to cycles of fasciculation and defasciculation. We found that this is controlled by rhythmic Rho1 activity that retracts s-LNv axonal termini by increasing myosin phosphorylation and simultaneously changes the balance of pre-synaptic and dendritic markers. This plasticity is required to change clock network hierarchy and allow seasonal adaptation. Rhythms in Rho1 activity are controlled by clock-regulated transcription of Puratrophin-1-like (Pura), a Rho1 GEF. Since spinocerebellar ataxia is associated with mutations in human Puratrophin-1, our data support the idea that defective actin-related plasticity underlies this ataxia.
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Affiliation(s)
- Afroditi Petsakou
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Themistoklis P Sapsis
- Courant Institute for Applied Mathematics, New York University, New York, NY 10003, USA; Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Justin Blau
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA; Center for Genomics & Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates; Program in Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
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27
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Belle MDC. Circadian Tick-Talking Across the Neuroendocrine System and Suprachiasmatic Nuclei Circuits: The Enigmatic Communication Between the Molecular and Electrical Membrane Clocks. J Neuroendocrinol 2015; 27:567-76. [PMID: 25845396 PMCID: PMC4973835 DOI: 10.1111/jne.12279] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 03/25/2015] [Accepted: 03/26/2015] [Indexed: 12/15/2022]
Abstract
As with many processes in nature, appropriate timing in biological systems is of paramount importance. In the neuroendocrine system, the efficacy of hormonal influence on major bodily functions, such as reproduction, metabolism and growth, relies on timely communication within and across many of the brain's homeostatic systems. The activity of these circuits is tightly orchestrated with the animal's internal physiological demands and external solar cycle by a master circadian clock. In mammals, this master clock is located in the hypothalamic suprachiasmatic nucleus (SCN), where the ensemble activity of thousands of clock neurones generates and communicates circadian time cues to the rest of the brain and body. Many regions of the brain, including areas with neuroendocrine function, also contain local daily clocks that can provide feedback signals to the SCN. Although much is known about the molecular processes underpinning endogenous circadian rhythm generation in SCN neurones and, to a lesser extent, extra-SCN cells, the electrical membrane clock that acts in partnership with the molecular clockwork to communicate circadian timing across the brain is poorly understood. The present review focuses on some circadian aspects of reproductive neuroendocrinology and processes involved in circadian rhythm communication in the SCN, aiming to identify key gaps in our knowledge of cross-talk between our daily master clock and neuroendocrine function. The intention is to highlight our surprisingly limited understanding of their interaction in the hope that this will stimulate future work in these areas.
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Affiliation(s)
- M. D. C. Belle
- Faculty of Life SciencesUniversity of ManchesterManchesterUK
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28
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Flourakis M, Allada R. Patch-clamp electrophysiology in Drosophila circadian pacemaker neurons. Methods Enzymol 2014; 552:23-44. [PMID: 25707271 DOI: 10.1016/bs.mie.2014.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Circadian clocks modulate the action potential firing frequency of pacemaker neurons. This daily variation in membrane excitability has been described in multiple species: from mollusks to fruit flies and mammals. Here, we provide an overview of the Drosophila pacemaker neural network, how circadian clocks drive neuronal activity within this network and we will present electrophysiological methods that we have applied to directly measure neuronal activity and reveal signal transduction pathways.
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Affiliation(s)
- Matthieu Flourakis
- Department of Neurobiology, Northwestern University, Evanston, Illinois, USA.
| | - Ravi Allada
- Department of Neurobiology, Northwestern University, Evanston, Illinois, USA.
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29
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Abruzzi K, Chen X, Nagoshi E, Zadina A, Rosbash M. RNA-seq profiling of small numbers of Drosophila neurons. Methods Enzymol 2014; 551:369-86. [PMID: 25662465 DOI: 10.1016/bs.mie.2014.10.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Drosophila melanogaster has a robust circadian clock, which drives a rhythmic behavior pattern: locomotor activity increases in the morning shortly before lights on (M peak) and in the evening shortly before lights off (E peak). This pattern is controlled by ~75 pairs of circadian neurons in the Drosophila brain. One key group of neurons is the M-cells (PDF(+) large and small LNvs), which control the M peak. A second key group is the E-cells, consisting of four LNds and the fifth small LNv, which control the E peak. Recent studies show that the M-cells have a second role in addition to controlling the M peak; they communicate with the E-cells (as well as DN1s) to affect their timing, probably as a function of environmental conditions (Guo, Cerullo, Chen, & Rosbash, 2014). To learn about molecules within the M-cells important for their functional roles, we have adapted methods to manually sort fluorescent protein-expressing neurons of interest from dissociated Drosophila brains. We isolated mRNA and miRNA from sorted M-cells and amplified the resulting DNAs to create deep-sequencing libraries. Visual inspection of the libraries illustrates that they are specific to a particular neuronal subgroup; M-cell libraries contain timeless and dopaminergic cell libraries contain ple/TH. Using these data, it is possible to identify cycling transcripts as well as many mRNAs and miRNAs specific to or enriched in particular groups of neurons.
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Affiliation(s)
- Katharine Abruzzi
- Department of Biology, Howard Hughes Medical Institute and National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts, USA
| | - Xiao Chen
- Department of Biology, Howard Hughes Medical Institute and National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts, USA
| | - Emi Nagoshi
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | - Abby Zadina
- Department of Biology, Howard Hughes Medical Institute and National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts, USA
| | - Michael Rosbash
- Department of Biology, Howard Hughes Medical Institute and National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts, USA.
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30
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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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31
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Seluzicki A, Flourakis M, Kula-Eversole E, Zhang L, Kilman V, Allada R. Dual PDF signaling pathways reset clocks via TIMELESS and acutely excite target neurons to control circadian behavior. PLoS Biol 2014; 12:e1001810. [PMID: 24643294 PMCID: PMC3958333 DOI: 10.1371/journal.pbio.1001810] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 02/05/2014] [Indexed: 12/20/2022] Open
Abstract
Molecular circadian clocks are interconnected via neural networks. In Drosophila, PIGMENT-DISPERSING FACTOR (PDF) acts as a master network regulator with dual functions in synchronizing molecular oscillations between disparate PDF(+) and PDF(-) circadian pacemaker neurons and controlling pacemaker neuron output. Yet the mechanisms by which PDF functions are not clear. We demonstrate that genetic inhibition of protein kinase A (PKA) in PDF(-) clock neurons can phenocopy PDF mutants while activated PKA can partially rescue PDF receptor mutants. PKA subunit transcripts are also under clock control in non-PDF DN1p neurons. To address the core clock target of PDF, we rescued per in PDF neurons of arrhythmic per⁰¹ mutants. PDF neuron rescue induced high amplitude rhythms in the clock component TIMELESS (TIM) in per-less DN1p neurons. Complete loss of PDF or PKA inhibition also results in reduced TIM levels in non-PDF neurons of per⁰¹ flies. To address how PDF impacts pacemaker neuron output, we focally applied PDF to DN1p neurons and found that it acutely depolarizes and increases firing rates of DN1p neurons. Surprisingly, these effects are reduced in the presence of an adenylate cyclase inhibitor, yet persist in the presence of PKA inhibition. We have provided evidence for a signaling mechanism (PKA) and a molecular target (TIM) by which PDF resets and synchronizes clocks and demonstrates an acute direct excitatory effect of PDF on target neurons to control neuronal output. The identification of TIM as a target of PDF signaling suggests it is a multimodal integrator of cell autonomous clock, environmental light, and neural network signaling. Moreover, these data reveal a bifurcation of PKA-dependent clock effects and PKA-independent output effects. Taken together, our results provide a molecular and cellular basis for the dual functions of PDF in clock resetting and pacemaker output.
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Affiliation(s)
- Adam Seluzicki
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
| | - Matthieu Flourakis
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
| | - Elzbieta Kula-Eversole
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
| | - Luoying Zhang
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
| | - Valerie Kilman
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
| | - Ravi Allada
- Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America
- * E-mail:
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32
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Tataroglu O, Emery P. Studying circadian rhythms in Drosophila melanogaster. Methods 2014; 68:140-50. [PMID: 24412370 DOI: 10.1016/j.ymeth.2014.01.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 01/02/2014] [Indexed: 11/25/2022] Open
Abstract
Circadian rhythms have a profound influence on most bodily functions: from metabolism to complex behaviors. They ensure that all these biological processes are optimized with the time-of-day. They are generated by endogenous molecular oscillators that have a period that closely, but not exactly, matches day length. These molecular clocks are synchronized by environmental cycles such as light intensity and temperature. Drosophila melanogaster has been a model organism of choice to understand genetically, molecularly and at the level of neural circuits how circadian rhythms are generated, how they are synchronized by environmental cues, and how they drive behavioral cycles such as locomotor rhythms. This review will cover a wide range of techniques that have been instrumental to our understanding of Drosophila circadian rhythms, and that are essential for current and future research.
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Affiliation(s)
- Ozgur Tataroglu
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, United States
| | - Patrick Emery
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, United States.
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33
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Diekman CO, Belle MDC, Irwin RP, Allen CN, Piggins HD, Forger DB. Causes and consequences of hyperexcitation in central clock neurons. PLoS Comput Biol 2013; 9:e1003196. [PMID: 23990770 PMCID: PMC3749949 DOI: 10.1371/journal.pcbi.1003196] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 06/06/2013] [Indexed: 12/20/2022] Open
Abstract
Hyperexcited states, including depolarization block and depolarized low amplitude membrane oscillations (DLAMOs), have been observed in neurons of the suprachiasmatic nuclei (SCN), the site of the central mammalian circadian (~24-hour) clock. The causes and consequences of this hyperexcitation have not yet been determined. Here, we explore how individual ionic currents contribute to these hyperexcited states, and how hyperexcitation can then influence molecular circadian timekeeping within SCN neurons. We developed a mathematical model of the electrical activity of SCN neurons, and experimentally verified its prediction that DLAMOs depend on post-synaptic L-type calcium current. The model predicts that hyperexcited states cause high intracellular calcium concentrations, which could trigger transcription of clock genes. The model also predicts that circadian control of certain ionic currents can induce hyperexcited states. Putting it all together into an integrative model, we show how membrane potential and calcium concentration provide a fast feedback that can enhance rhythmicity of the intracellular circadian clock. This work puts forward a novel role for electrical activity in circadian timekeeping, and suggests that hyperexcited states provide a general mechanism for linking membrane electrical dynamics to transcription activation in the nucleus.
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Affiliation(s)
- Casey O. Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey, United States of America
| | - Mino D. C. Belle
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Robert P. Irwin
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Charles N. Allen
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Hugh D. Piggins
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Daniel B. Forger
- Department of Mathematics and Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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34
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Muraro NI, Pírez N, Ceriani MF. The circadian system: plasticity at many levels. Neuroscience 2013; 247:280-93. [PMID: 23727010 DOI: 10.1016/j.neuroscience.2013.05.036] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 05/17/2013] [Accepted: 05/20/2013] [Indexed: 11/16/2022]
Abstract
Over the years it has become crystal clear that a variety of processes encode time-of-day information, ranging from gene expression, protein stability, or subcellular localization of key proteins, to the fine tuning of network properties and modulation of input signals, ultimately ensuring that physiology and behavior are properly synchronized to a changing environment. The purpose of this review is to put forward examples (as opposed to generate a comprehensive revision of all the available literature) in which the circadian system displays a remarkable degree of plasticity, from cell autonomous to circuit-based levels. In the literature, the term circadian plasticity has been used to refer to different concepts. The obvious one, more literally, refers to any change that follows a circadian (circa=around, diem=day) pattern, i.e. a daily change of a given parameter. The discovery of daily remodeling of neuronal structures will be referred herein as structural circadian plasticity, and represents an additional and novel phenomenon modified daily. Finally, any plasticity that has to do with a circadian parameter would represent a type of circadian plasticity; as an example, adjustments that allow organisms to adapt their daily behavior to the annual changes in photoperiod is a form of circadian plasticity at a higher organizational level, which is an emergent property of the whole circadian system. Throughout this work we will revisit these types of changes by reviewing recent literature delving around circadian control of clock outputs, from the most immediate ones within pacemaker neurons to the circadian modulation of rest-activity cycles.
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Affiliation(s)
- N I Muraro
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIB-BA-CONICET, Buenos Aires, Argentina
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35
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Brancaccio M, Maywood ES, Chesham JE, Loudon ASI, Hastings MH. A Gq-Ca2+ axis controls circuit-level encoding of circadian time in the suprachiasmatic nucleus. Neuron 2013; 78:714-28. [PMID: 23623697 PMCID: PMC3666084 DOI: 10.1016/j.neuron.2013.03.011] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2013] [Indexed: 11/30/2022]
Abstract
The role of intracellular transcriptional/post-translational feedback loops (TTFL) within the circadian pacemaker of the suprachiasmatic nucleus (SCN) is well established. In contrast, contributions from G-coupled pathways and cytosolic rhythms to the intercellular control of SCN pacemaking are poorly understood. We therefore combined viral transduction of SCN slices with fluorescence/bioluminescence imaging to visualize GCaMP3-reported circadian oscillations of intracellular calcium [Ca2+]i alongside activation of Ca2+/cAMP-responsive elements. We phase-mapped them to the TTFL, in time and SCN space, and demonstrated their dependence upon G-coupled vasoactive intestinal peptide (VIP) signaling. Pharmacogenetic manipulation revealed the individual contributions of Gq, Gs, and Gi to cytosolic and TTFL circadian rhythms. Importantly, activation of Gq-dependent (but not Gs or Gi) pathways in a minority of neurons reprogrammed [Ca2+]i and TTFL rhythms across the entire SCN. This reprogramming was mediated by intrinsic VIPergic signaling, thus revealing a Gq/[Ca2+]i-VIP leitmotif and unanticipated plasticity within network encoding of SCN circadian time. SCN [Ca2+]i and TTFL circadian landscape phase-mapped by real-time imaging SCN network reprogrammed by recruitment of Gq-[Ca2+]i axis in a minority of neurons Selective Gq-mediated reprogramming mediated by intrinsic VIPergic signaling Internal structure and unanticipated plasticity of the SCN circadian network unveiled
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Affiliation(s)
- Marco Brancaccio
- Division of Neurobiology, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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36
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Aguilar-Arnal L, Sassone-Corsi P. The circadian epigenome: how metabolism talks to chromatin remodeling. Curr Opin Cell Biol 2013; 25:170-6. [PMID: 23385084 DOI: 10.1016/j.ceb.2013.01.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Accepted: 01/02/2013] [Indexed: 01/20/2023]
Abstract
Circadian rhythms occur in most of the living organisms, and with a 24 hour periodicity govern a number of physiological and metabolic functions. During the past few years, an important research effort has uncovered new trails that intersect between circadian rhythms and metabolic pathways. At a molecular level, the clock machinery is responsible for the establishment of a circadian epigenome, and this can be modulated by metabolic cues. Indeed, metabolic control by the circadian clock is manifest in the development of metabolic diseases when circadian rhythms are impaired. Thus, pharmacological modulation of circadian rhythms promises new avenues for the treatment of metabolic and sleep disorders.
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Affiliation(s)
- Lorena Aguilar-Arnal
- Center for Epigenetics and Metabolism, Unité 904 Institut National de la Santé et de la Recherche Médicale (INSERM)
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37
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