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Van Loh BM, Yaw AM, Breuer JA, Jackson B, Nguyen D, Jang K, Ramos F, Ho EV, Cui LJ, Gillette DLM, Sempere LF, Gorman MR, Tonsfeldt KJ, Mellon PL, Hoffmann HM. The transcription factor VAX1 in VIP neurons of the suprachiasmatic nucleus impacts circadian rhythm generation, depressive-like behavior, and the reproductive axis in a sex-specific manner in mice. Front Endocrinol (Lausanne) 2023; 14:1269672. [PMID: 38205198 PMCID: PMC10777845 DOI: 10.3389/fendo.2023.1269672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 11/28/2023] [Indexed: 01/12/2024] Open
Abstract
Background The suprachiasmatic nucleus (SCN) within the hypothalamus is a key brain structure required to relay light information to the body and synchronize cell and tissue level rhythms and hormone release. Specific subpopulations of SCN neurons, defined by their peptide expression, regulate defined SCN output. Here we focus on the vasoactive intestinal peptide (VIP) expressing neurons of the SCN. SCN VIP neurons are known to regulate circadian rhythms and reproductive function. Methods To specifically study SCN VIP neurons, we generated a novel knock out mouse line by conditionally deleting the SCN enriched transcription factor, Ventral Anterior Homeobox 1 (Vax1), in VIP neurons (Vax1Vip; Vax1fl/fl:VipCre). Results We found that Vax1Vip females presented with lengthened estrous cycles, reduced circulating estrogen, and increased depressive-like behavior. Further, Vax1Vip males and females presented with a shortened circadian period in locomotor activity and ex vivo SCN circadian period. On a molecular level, the shortening of the SCN period was driven, at least partially, by a direct regulatory role of VAX1 on the circadian clock genes Bmal1 and Per2. Interestingly, Vax1Vip females presented with increased expression of arginine vasopressin (Avp) in the paraventricular nucleus, which resulted in increased circulating corticosterone. SCN VIP and AVP neurons regulate the reproductive gonadotropin-releasing hormone (GnRH) and kisspeptin neurons. To determine how the reproductive neuroendocrine network was impacted in Vax1Vip mice, we assessed GnRH sensitivity to a kisspeptin challenge in vivo. We found that GnRH neurons in Vax1Vip females, but not males, had an increased sensitivity to kisspeptin, leading to increased luteinizing hormone release. Interestingly, Vax1Vip males showed a small, but significant increase in total sperm and a modest delay in pubertal onset. Both male and female Vax1Vip mice were fertile and generated litters comparable in size and frequency to controls. Conclusion Together, these data identify VAX1 in SCN VIP neurons as a neurological overlap between circadian timekeeping, female reproduction, and depressive-like symptoms in mice, and provide novel insight into the role of SCN VIP neurons.
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Affiliation(s)
- Brooke M. Van Loh
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Alexandra M. Yaw
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Joseph A. Breuer
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Brooke Jackson
- Department of Radiology and Precision Health Program, Michigan State University, East Lansing, MI, United States
| | - Duong Nguyen
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Krystal Jang
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Fabiola Ramos
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
| | - Emily V. Ho
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Laura J. Cui
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Dominique L. M. Gillette
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Lorenzo F. Sempere
- Department of Radiology and Precision Health Program, Michigan State University, East Lansing, MI, United States
| | - Michael R. Gorman
- Department of Psychology, University of California, San Diego, La Jolla, CA, United States
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
| | - Karen J. Tonsfeldt
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
| | - Pamela L. Mellon
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
| | - Hanne M. Hoffmann
- Department of Animal Science and the Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, MI, United States
- Department of Obstetrics, Gynecology, and Reproductive Sciences and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA, United States
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Potential Role of the Circadian Clock in the Regulation of Cancer Stem Cells and Cancer Therapy. Int J Mol Sci 2022; 23:ijms232214181. [PMID: 36430659 PMCID: PMC9698777 DOI: 10.3390/ijms232214181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022] Open
Abstract
Circadian rhythms, including sleep/wake cycles as well as hormonal, immune, metabolic, and cell proliferation rhythms, are fundamental biological processes driven by a cellular time-keeping system called the circadian clock. Disruptions in these rhythms due to genetic alterations or irregular lifestyles cause fundamental changes in physiology, from metabolism to cellular proliferation and differentiation, resulting in pathological consequences including cancer. Cancer cells are not uniform and static but exist as different subtypes with phenotypic and functional differences in the tumor microenvironment. At the top of the heterogeneous tumor cell hierarchy, cancer stem cells (CSCs), a self-renewing and multi-potent cancer cell type, are most responsible for tumor recurrence and metastasis, chemoresistance, and mortality. Phenotypically, CSCs are associated with the epithelial-mesenchymal transition (EMT), which confers cancer cells with increased motility and invasion ability that is characteristic of malignant and drug-resistant stem cells. Recently, emerging studies of different cancer types, such as glioblastoma, leukemia, prostate cancer, and breast cancer, suggest that the circadian clock plays an important role in the maintenance of CSC/EMT characteristics. In this review, we describe recent discoveries regarding how tumor intrinsic and extrinsic circadian clock-regulating factors affect CSC evolution, highlighting the possibility of developing novel chronotherapeutic strategies that could be used against CSCs to fight cancer.
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Hartsock MJ, Strnad HK, Spencer RL. Iterative Metaplasticity Across Timescales: How Circadian, Ultradian, and Infradian Rhythms Modulate Memory Mechanisms. J Biol Rhythms 2021; 37:29-42. [PMID: 34781753 DOI: 10.1177/07487304211058256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Work in recent years has provided strong evidence for the modulation of memory function and neuroplasticity mechanisms across circadian (daily), ultradian (shorter-than-daily), and infradian (longer-than-daily) timescales. Despite rapid progress, however, the field has yet to adopt a general framework to describe the overarching role of biological rhythms in memory. To this end, Iyer and colleagues introduced the term iterative metaplasticity, which they define as the "gating of receptivity to subsequent signals that repeats on a cyclic timebase." The central concept is that the cyclic regulation of molecules involved in neuroplasticity may produce cycles in neuroplastic capacity-that is, the ability of neural cells to undergo activity-dependent change. Although Iyer and colleagues focus on the circadian timescale, we think their framework may be useful for understanding how biological rhythms influence memory more broadly. In this review, we provide examples and terminology to explain how the idea of iterative metaplasticity can be readily applied across circadian, ultradian, and infradian timescales. We suggest that iterative metaplasticity may not only support the temporal niching of neuroplasticity processes but also serve an essential role in the maintenance of memory function.
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Affiliation(s)
- Matthew J Hartsock
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado
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4
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Buijink MR, Michel S. A multi-level assessment of the bidirectional relationship between aging and the circadian clock. J Neurochem 2021; 157:73-94. [PMID: 33370457 PMCID: PMC8048448 DOI: 10.1111/jnc.15286] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022]
Abstract
The daily temporal order of physiological processes and behavior contribute to the wellbeing of many organisms including humans. The central circadian clock, which coordinates the timing within our body, is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Like in other parts of the brain, aging impairs the SCN function, which in turn promotes the development and progression of aging-related diseases. We here review the impact of aging on the different levels of the circadian clock machinery-from molecules to organs-with a focus on the role of the SCN. We find that the molecular clock is less effected by aging compared to other cellular components of the clock. Proper rhythmic regulation of intracellular signaling, ion channels and neuronal excitability of SCN neurons are greatly disturbed in aging. This suggests a disconnection between the molecular clock and the electrophysiology of these cells. The neuronal network of the SCN is able to compensate for some of these cellular deficits. However, it still results in a clear reduction in the amplitude of the SCN electrical rhythm, suggesting a weakening of the output timing signal. Consequently, other brain areas and organs not only show aging-related deficits in their own local clocks, but also receive a weaker systemic timing signal. The negative spiral completes with the weakening of positive feedback from the periphery to the SCN. Consequently, chronotherapeutic interventions should aim at strengthening overall synchrony in the circadian system using life-style and/or pharmacological approaches.
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Affiliation(s)
- M. Renate Buijink
- Department of Cellular and Chemical BiologyLaboratory for NeurophysiologyLeiden University Medical CenterLeidenthe Netherlands
| | - Stephan Michel
- Department of Cellular and Chemical BiologyLaboratory for NeurophysiologyLeiden University Medical CenterLeidenthe Netherlands
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Michel S, Nakamura TJ, Meijer JH, Colwell CS. Electrophysiological Approaches to Studying the Suprachiasmatic Nucleus. Methods Mol Biol 2021; 2130:303-324. [PMID: 33284454 DOI: 10.1007/978-1-0716-0381-9_23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In mammals, the part of the nervous system responsible for most circadian behavior can be localized to a bilaterally paired structure in the hypothalamus known as the suprachiasmatic nucleus (SCN). Understanding the mammalian circadian system will require a detailed multilevel analysis of neural SCN circuits ex vivo and in vivo. Many of the techniques and approaches that are used for the analysis of the circuitry driving circadian oscillations in the SCN are similar to those employed in other brain regions. There is, however, one fundamental difference that needs to be taken into consideration, that is, the physiological, cell, and molecular properties of SCN neurons vary with the time of day. In this chapter, we will consider the preparations and electrophysiological techniques that we have used to analyze the SCN circuit focusing on the acute brain slice and intact, freely moving animal.
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Affiliation(s)
- Stephan Michel
- Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Takahiro J Nakamura
- Laboratory of Animal Physiology, Department of Life Sciences, School of Agriculture, Meiji University, Tama-ku Kawasaki, Kanagawa, Japan
| | - Johanna H Meijer
- Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Christopher S Colwell
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA
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6
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Ma Q, Mo G, Tan Y. Micro RNAs and the biological clock: a target for diseases associated with a loss of circadian regulation. Afr Health Sci 2020; 20:1887-1894. [PMID: 34394254 PMCID: PMC8351835 DOI: 10.4314/ahs.v20i4.46] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Background Circadian clocks are self-sustaining oscillators that coordinate behavior and physiology over a 24 hour period, achieving time-dependent homeostasis with the external environment. The molecular clocks driving circadian rhythmic changes are based on intertwined transcriptional/translational feedback loops that combine with a range of environmental and metabolic stimuli to generate daily internal programing. Understanding how biological rhythms are generated throughout the body and the reasons for their dysregulation can provide avenues for temporally directed therapeutics. Summary In recent years, microRNAs have been shown to play important roles in the regulation of the circadian clock, particularly in Drosophila, but also in some small animal and human studies. This review will summarize our current understanding of the role of miRNAs during clock regulation, with a particular focus on the control of clock regulated gene expression.
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Affiliation(s)
- Qianwen Ma
- Gynecology department, Zhenjiang Hospital Affiliated to Nanjing University of Chinese Medicine (Zhenjiang Hospital of Traditional Chinese Medicine), Zhenjiang, China
- Reproductive medicine department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Genlin Mo
- Advanced manufacturing institution, Jiangsu University, Zhenjiang, China
| | - Yong Tan
- Reproductive medicine department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
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7
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Hartsock MJ, Spencer RL. Memory and the circadian system: Identifying candidate mechanisms by which local clocks in the brain may regulate synaptic plasticity. Neurosci Biobehav Rev 2020; 118:134-162. [PMID: 32712278 DOI: 10.1016/j.neubiorev.2020.07.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 07/14/2020] [Accepted: 07/18/2020] [Indexed: 12/11/2022]
Abstract
The circadian system is an endogenous biological network responsible for coordinating near-24-h cycles in behavior and physiology with daily timing cues from the external environment. In this review, we explore how the circadian system regulates memory formation, retention, and recall. Circadian rhythms in these memory processes may arise through several endogenous pathways, and recent work highlights the importance of genetic timekeepers found locally within tissues, called local clocks. We evaluate the circadian memory literature for evidence of local clock involvement in memory, identifying potential nodes for direct interactions between local clock components and mechanisms of synaptic plasticity. Our discussion illustrates how local clocks may pervasively modulate neuronal plastic capacity, a phenomenon that we designate here as circadian metaplasticity. We suggest that this function of local clocks supports the temporal optimization of memory processes, illuminating the potential for circadian therapeutic strategies in the prevention and treatment of memory impairment.
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Affiliation(s)
- Matthew J Hartsock
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado 80309, United States.
| | - Robert L Spencer
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado 80309, United States.
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8
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Harvey JRM, Plante AE, Meredith AL. Ion Channels Controlling Circadian Rhythms in Suprachiasmatic Nucleus Excitability. Physiol Rev 2020; 100:1415-1454. [PMID: 32163720 DOI: 10.1152/physrev.00027.2019] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Animals synchronize to the environmental day-night cycle by means of an internal circadian clock in the brain. In mammals, this timekeeping mechanism is housed in the suprachiasmatic nucleus (SCN) of the hypothalamus and is entrained by light input from the retina. One output of the SCN is a neural code for circadian time, which arises from the collective activity of neurons within the SCN circuit and comprises two fundamental components: 1) periodic alterations in the spontaneous excitability of individual neurons that result in higher firing rates during the day and lower firing rates at night, and 2) synchronization of these cellular oscillations throughout the SCN. In this review, we summarize current evidence for the identity of ion channels in SCN neurons and the mechanisms by which they set the rhythmic parameters of the time code. During the day, voltage-dependent and independent Na+ and Ca2+ currents, as well as several K+ currents, contribute to increased membrane excitability and therefore higher firing frequency. At night, an increase in different K+ currents, including Ca2+-activated BK currents, contribute to membrane hyperpolarization and decreased firing. Layered on top of these intrinsically regulated changes in membrane excitability, more than a dozen neuromodulators influence action potential activity and rhythmicity in SCN neurons, facilitating both synchronization and plasticity of the neural code.
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Affiliation(s)
- Jenna R M Harvey
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Amber E Plante
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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9
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El Cheikh Hussein L, Mollard P, Bonnefont X. Molecular and Cellular Networks in The Suprachiasmatic Nuclei. Int J Mol Sci 2019; 20:ijms20082052. [PMID: 31027315 PMCID: PMC6514755 DOI: 10.3390/ijms20082052] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/20/2022] Open
Abstract
Why do we experience the ailments of jetlag when we travel across time zones? Why is working night-shifts so detrimental to our health? In other words, why can’t we readily choose and stick to non-24 h rhythms? Actually, our daily behavior and physiology do not simply result from the passive reaction of our organism to the external cycle of days and nights. Instead, an internal clock drives the variations in our bodily functions with a period close to 24 h, which is supposed to enhance fitness to regular and predictable changes of our natural environment. This so-called circadian clock relies on a molecular mechanism that generates rhythmicity in virtually all of our cells. However, the robustness of the circadian clock and its resilience to phase shifts emerge from the interaction between cell-autonomous oscillators within the suprachiasmatic nuclei (SCN) of the hypothalamus. Thus, managing jetlag and other circadian disorders will undoubtedly require extensive knowledge of the functional organization of SCN cell networks. Here, we review the molecular and cellular principles of circadian timekeeping, and their integration in the multi-cellular complexity of the SCN. We propose that new, in vivo imaging techniques now enable to address these questions directly in freely moving animals.
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Affiliation(s)
- Lama El Cheikh Hussein
- Institut de Génomique Fonctionnelle (IGF), University Montpellier, CNRS, INSERM, 34094 Montpellier, France.
| | - Patrice Mollard
- Institut de Génomique Fonctionnelle (IGF), University Montpellier, CNRS, INSERM, 34094 Montpellier, France.
| | - Xavier Bonnefont
- Institut de Génomique Fonctionnelle (IGF), University Montpellier, CNRS, INSERM, 34094 Montpellier, France.
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10
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Collins B, Brown SA. Beyond the molecular clock. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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11
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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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12
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Abitbol K, Debiesse S, Molino F, Mesirca P, Bidaud I, Minami Y, Mangoni ME, Yagita K, Mollard P, Bonnefont X. Clock-dependent and system-driven oscillators interact in the suprachiasmatic nuclei to pace mammalian circadian rhythms. PLoS One 2017; 12:e0187001. [PMID: 29059248 PMCID: PMC5653358 DOI: 10.1371/journal.pone.0187001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/11/2017] [Indexed: 12/04/2022] Open
Abstract
Circadian clocks drive biological rhythms with a period of approximately 24 hours and keep in time with the outside world through daily resetting by environmental cues. While this external entrainment has been extensively investigated in the suprachiasmatic nuclei (SCN), the role of internal systemic rhythms, including daily fluctuations in core temperature or circulating hormones remains debated. Here, we show that lactating mice, which exhibit dampened systemic rhythms, possess normal molecular clockwork but impaired rhythms in both heat shock response gene expression and electrophysiological output in their SCN. This suggests that body rhythms regulate SCN activity downstream of the clock. Mathematical modeling predicts that systemic feedback upon the SCN functions as an internal oscillator that accounts for in vivo and ex vivo observations. Thus we are able to propose a new bottom-up hierarchical organization of circadian timekeeping in mammals, based on the interaction in the SCN between clock-dependent and system-driven oscillators.
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Affiliation(s)
- Karine Abitbol
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Ségolène Debiesse
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - François Molino
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
- Laboratoire Charles Coulomb, Université de Montpellier, CNRS UMR 5221, Montpellier, France
| | - Pietro Mesirca
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Isabelle Bidaud
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Yoichi Minami
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Matteo E. Mangoni
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Kazuhiro Yagita
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Patrice Mollard
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
| | - Xavier Bonnefont
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Montpellier, France
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13
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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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14
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Jones JR, McMahon DG. The core clock gene Per1 phases molecular and electrical circadian rhythms in SCN neurons. PeerJ 2016; 4:e2297. [PMID: 27602274 PMCID: PMC4991845 DOI: 10.7717/peerj.2297] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/06/2016] [Indexed: 11/20/2022] Open
Abstract
The brain’s biological clock, the suprachiasmatic nucleus (SCN), exhibits endogenous 24-hour rhythms in gene expression and spontaneous firing rate; however, the functional relationship between these neuronal rhythms is not fully understood. Here, we used a Per1::GFP transgenic mouse line that allows for the simultaneous quantification of molecular clock state and firing rate in SCN neurons to examine the relationship between these key components of the circadian clock. We find that there is a stable, phased relationship between E-box-driven clock gene expression and spontaneous firing rate in SCN neurons and that these relationships are independent of light input onto the system or of GABAA receptor-mediated synaptic activity. Importantly, the concordant phasing of gene and neural rhythms is disrupted in the absence of the homologous clock gene Per1, but persists in the absence of the core clock gene Per2. These results suggest that Per1 plays a unique, non-redundant role in phasing gene expression and firing rate rhythms in SCN neurons to increase the robustness of cellular timekeeping.
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Affiliation(s)
- Jeff R Jones
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN, United States; Current affiliation: Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
| | - Douglas G McMahon
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN, United States; Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
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