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Li M, Liu X, Li J, Guo H, Xue S, Zhu L, Ma C, Chen D, Wang H, Cai Y, Shen J. Brain glycogen: A key to revealing the pathology of mental diseases. Brain Res 2024; 1844:149194. [PMID: 39182899 DOI: 10.1016/j.brainres.2024.149194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 08/16/2024] [Accepted: 08/21/2024] [Indexed: 08/27/2024]
Abstract
Brain glycogen, which is distinct from muscle glycogen and liver glycogen, has become a crucial node linking metabolism, epigenetics, and autophagy. Recent studies have suggested that brain glycogen governs multiple neurobehavioral processes, such as memory formation and consolidation. However, the changes in brain glycogen levels in mental diseases and the associations of these changes with the disease prognosis are unknown. Here, we review the psychological functions of brain glycogen and the different characteristics of astrocytic glycogen and neuronal glycogen. In addition, we summarize the alterations in brain glycogen levels in depression, schizophrenia and sleep disorders, highlighting that brain glycogen functions as an important metabolite responsible for the development of mental diseases. In summary, brain glycogen is a key to understanding the pathology of mental diseases and deserves more attention in future research.
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Affiliation(s)
- Mingyu Li
- Graduate School, Xi׳an Medical University, Xi'an, Shaanxi, China
| | - Xiaohui Liu
- Department of Psychiatry, Xijing 986 Hospital Department, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jing Li
- Department of Psychiatry, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Haiyun Guo
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Shanshan Xue
- Department of Psychiatry, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Lei Zhu
- Graduate School, Xi׳an Medical University, Xi'an, Shaanxi, China
| | - Cuicui Ma
- Department of Psychiatry, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Dongyu Chen
- Department of Psychiatry, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Huaning Wang
- Department of Psychiatry, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yanhui Cai
- Department of Psychiatry, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
| | - Jiangpei Shen
- Department of Psychiatry, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
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2
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Rodrigues NR, Macedo GE, Martins IK, Vieira PDB, Kich KG, Posser T, Franco JL. Sleep disturbance induces a modulation of clock gene expression and alters metabolism regulation in drosophila. Physiol Behav 2023; 271:114334. [PMID: 37595818 DOI: 10.1016/j.physbeh.2023.114334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/20/2023]
Abstract
Sleep disorders are catching attention worldwide as they can induce dyshomeostasis and health issues in all animals, including humans. Circadian rhythms are biological 24-hour cycles that influence physiology and behavior in all living organisms. Sleep is a crucial resting state for survival and is under the control of circadian rhythms. Studies have shown the influence of sleep on various pathological conditions, including metabolic diseases; however, the biological mechanisms involving the circadian clock, sleep, and metabolism regulation are not well understood. In previous work, we standardized a sleep disturbance protocol and, observed that short-time sleep deprivation and sleep-pattern alteration induce homeostatic sleep regulation, locomotor deficits, and increase oxidative stress. Now, we investigated the relationship between these alterations with the circadian clock and energetic metabolism. In this study, we evaluated the expression of the circadian clock and drosophila insulin-like peptides (DILPs) genes and metabolic markers glucose, triglycerides, and glycogen in fruit flies subjected to short-term sleep disruption protocols. The sleep disturbance altered the expression of clock genes and DILPs genes expression, and modulated glucose, triglycerides, and glycogen levels. Moreover, we demonstrated changes in mTor/dFoxo genes, AKT phosphorylation, and dopamine levels in nocturnal light-exposed flies. Thus, our results suggest a connection between clock genes and metabolism disruption as a consequence of sleep disruption, demonstrating the importance of sleep quality in health maintenance.
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Affiliation(s)
- Nathane Rosa Rodrigues
- Grupo de Pesquisa Estresse Oxidativo e Sinalização Celular, Centro Interdisciplinar de Pesquisas em Biotecnologia, Universidade Federal do Pampa (UNIPAMPA), São Gabriel, RS, 97307-020, Brazil; Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria Santa Maria, RS, 97105-900, Brazil.
| | - Giulianna Echeverria Macedo
- Grupo de Pesquisa Estresse Oxidativo e Sinalização Celular, Centro Interdisciplinar de Pesquisas em Biotecnologia, Universidade Federal do Pampa (UNIPAMPA), São Gabriel, RS, 97307-020, Brazil
| | - Illana Kemmerich Martins
- Grupo de Pesquisa Estresse Oxidativo e Sinalização Celular, Centro Interdisciplinar de Pesquisas em Biotecnologia, Universidade Federal do Pampa (UNIPAMPA), São Gabriel, RS, 97307-020, Brazil
| | - Patrícia de Brum Vieira
- Grupo de Pesquisa Estresse Oxidativo e Sinalização Celular, Centro Interdisciplinar de Pesquisas em Biotecnologia, Universidade Federal do Pampa (UNIPAMPA), São Gabriel, RS, 97307-020, Brazil
| | - Karen Gomes Kich
- Grupo de Pesquisa Estresse Oxidativo e Sinalização Celular, Centro Interdisciplinar de Pesquisas em Biotecnologia, Universidade Federal do Pampa (UNIPAMPA), São Gabriel, RS, 97307-020, Brazil
| | - Thaís Posser
- Grupo de Pesquisa Estresse Oxidativo e Sinalização Celular, Centro Interdisciplinar de Pesquisas em Biotecnologia, Universidade Federal do Pampa (UNIPAMPA), São Gabriel, RS, 97307-020, Brazil
| | - Jeferson Luis Franco
- Grupo de Pesquisa Estresse Oxidativo e Sinalização Celular, Centro Interdisciplinar de Pesquisas em Biotecnologia, Universidade Federal do Pampa (UNIPAMPA), São Gabriel, RS, 97307-020, Brazil; Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria Santa Maria, RS, 97105-900, Brazil
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3
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Lai ML, Li AQ, Senior AM, Neely GG, Simpson SJ, Wang QP. Nutritional geometry framework of sleep. Life Sci 2023; 316:121381. [PMID: 36640899 DOI: 10.1016/j.lfs.2023.121381] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 12/30/2022] [Accepted: 01/07/2023] [Indexed: 01/13/2023]
Abstract
AIMS Sleep is a fundamental physiological function and is essential for all animals. Sleep is affected by diet compositions including protein (P) and carbohydrates (C), but there has not been a systematic investigation on the effect of dietary macronutrient balance on sleep. MAIN METHODS We used the nutritional geometry framework (NGF) to explore the interactive effects on sleep of protein (P) and carbohydrates (C) in the model organism Drosophila. Both female and male flies were fed various diets containing seven ratios of protein-to-carbohydrates at different energetic levels for 5 days and sleep was monitored by the Drosophila Activity Monitor (DAM) system. KEY FINDINGS Our results showed that the combination of low protein and high carbohydrates (LPHC) prolonged sleep time and sleep quality, with fewer sleep episodes and longer sleep duration. We further found that the effects of macronutrients on sleep mirrored levels of hemolymph glucose and whole-body glycogen. Moreover, transcriptomic analyses revealed that a high-protein, low-carbohydrate (HPLC) diet significantly elevated the gene expression of metabolic pathways when compared to the LPHC diet, with the glycine, serine, and threonine metabolism pathway being most strongly elevated. Further studies confirmed that the contents of glycine, serine, and threonine affected sleep. SIGNIFICANCE Our results demonstrate that sleep is affected by the dietary balance of protein and carbohydrates possibly mediated by the change in glucose, glycogen, glycine, serine, and threonine.
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Affiliation(s)
- Mei-Ling Lai
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen 518107, China
| | - An-Qi Li
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen 518107, China
| | - Alistair M Senior
- Charles Perkins Centre and School of Life & Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - G Gregory Neely
- The Dr. John and Anne Chong Laboratory for Functional Genomics, Charles Perkins Centre and School of Life & Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Stephen J Simpson
- Charles Perkins Centre and School of Life & Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Qiao-Ping Wang
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen 518107, China.
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Contreras EG, Sierralta J. The Fly Blood-Brain Barrier Fights Against Nutritional Stress. Neurosci Insights 2022; 17:26331055221120252. [PMID: 36225749 PMCID: PMC9549514 DOI: 10.1177/26331055221120252] [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: 05/25/2022] [Accepted: 08/01/2022] [Indexed: 11/17/2022] Open
Abstract
In the wild, animals face different challenges including multiple events of food
scarcity. How they overcome these conditions is essential for survival. Thus,
adaptation mechanisms evolved to allow the development and survival of an
organism during nutrient restriction periods. Given the high energy demand of
the nervous system, the molecular mechanisms of adaptation to malnutrition are
of great relevance to fuel the brain. The blood-brain barrier (BBB) is the
interface between the central nervous system (CNS) and the circulatory system.
The BBB mediates the transport of macromolecules in and out of the CNS, and
therefore, it can buffer changes in nutrient availability. In this review, we
collect the current evidence using the fruit fly, Drosophila
melanogaster, as a model of the role of the BBB in the adaptation
to starvation. We discuss the role of the Drosophila BBB during
nutrient deprivation as a potential sensor for circulating nutrients, and
transient nutrient storage as a regulator of the CNS neurogenic niche.
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Affiliation(s)
- Esteban G Contreras
- Institute of Neuro- and Behavioral Biology, University of Münster, Münster, Germany
| | - Jimena Sierralta
- Biomedical Neuroscience Institute and Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
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5
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Epiney DG, Salameh C, Cassidy D, Zhou LT, Kruithof J, Milutinović R, Andreani TS, Schirmer AE, Bolterstein E. Characterization of Stress Responses in a Drosophila Model of Werner Syndrome. Biomolecules 2021; 11:1868. [PMID: 34944512 PMCID: PMC8699552 DOI: 10.3390/biom11121868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/04/2021] [Accepted: 12/07/2021] [Indexed: 11/16/2022] Open
Abstract
As organisms age, their resistance to stress decreases while their risk of disease increases. This can be shown in patients with Werner syndrome (WS), which is a genetic disease characterized by accelerated aging along with increased risk of cancer and metabolic disease. WS is caused by mutations in WRN, a gene involved in DNA replication and repair. Recent research has shown that WRN mutations contribute to multiple hallmarks of aging including genomic instability, telomere attrition, and mitochondrial dysfunction. However, questions remain regarding the onset and effect of stress on early aging. We used a fly model of WS (WRNexoΔ) to investigate stress response during different life stages and found that stress sensitivity varies according to age and stressor. While larvae and young WRNexoΔ adults are not sensitive to exogenous oxidative stress, high antioxidant activity suggests high levels of endogenous oxidative stress. WRNexoΔ adults are sensitive to stress caused by elevated temperature and starvation suggesting abnormalities in energy storage and a possible link to metabolic dysfunction in WS patients. We also observed higher levels of sleep in aged WRNexoΔ adults suggesting an additional adaptive mechanism to protect against age-related stress. We suggest that stress response in WRNexoΔ is multifaceted and evokes a systemic physiological response to protect against cellular damage. These data further validate WRNexoΔ flies as a WS model with which to study mechanisms of early aging and provide a foundation for development of treatments for WS and similar diseases.
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Affiliation(s)
- Derek G. Epiney
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Charlotte Salameh
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Deirdre Cassidy
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Luhan T. Zhou
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Joshua Kruithof
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Rolan Milutinović
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Tomas S. Andreani
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA;
| | - Aaron E. Schirmer
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Elyse Bolterstein
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
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6
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Petit JM, Eren-Koçak E, Karatas H, Magistretti P, Dalkara T. Brain glycogen metabolism: A possible link between sleep disturbances, headache and depression. Sleep Med Rev 2021; 59:101449. [PMID: 33618186 DOI: 10.1016/j.smrv.2021.101449] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 12/27/2022]
Abstract
The functions of sleep and its links with neuropsychiatric diseases have long been questioned. Among the numerous hypotheses on sleep function, early studies proposed that sleep helps to replenish glycogen stores consumed during waking. Later studies found increased brain glycogen after sleep deprivation, leading to "glycogenetic" hypothesis, which states that there is a parallel increase in synthesis and utilization of glycogen during wakefulness, whereas decrease in the excitatory transmission creates an imbalance causing accumulation of glycogen during sleep. Glycogen is a vital energy reservoir to match the synaptic demand particularly for re-uptake of potassium and glutamate during intense glutamatergic transmission. Therefore, sleep deprivation-induced transcriptional changes may trigger migraine by reducing glycogen availability, which slows clearance of extracellular potassium and glutamate, hence, creates susceptibility to cortical spreading depolarization, the electrophysiological correlate of migraine aura. Interestingly, chronic stress accompanied by increased glucocorticoid levels and locus coeruleus activity and leading to mood disorders in which sleep disturbances are prevalent, also affects brain glycogen turnover via glucocorticoids, noradrenaline, serotonin and adenosine. These observations altogether suggest that inadequate astrocytic glycogen turnover may be one of the mechanisms linking migraine, mood disorders and sleep.
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Affiliation(s)
- J-M Petit
- Lausanne University Hospital, Center for Psychiatric Neuroscience, Prilly, Switzerland.
| | - E Eren-Koçak
- Hacettepe University, Institute of Neurological Sciences and Psychiatry, and Faculty of Medicine, Department of Psychiatry, Ankara, Turkey.
| | - H Karatas
- Hacettepe University, Institute of Neurological Sciences and Psychiatry, Ankara, Turkey.
| | - P Magistretti
- King Abdullah University of Science and Technology, Saudi Arabia.
| | - T Dalkara
- Hacettepe University, Institute of Neurological Sciences and Psychiatry, Ankara, Turkey.
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7
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Koyama T, Texada MJ, Halberg KA, Rewitz K. Metabolism and growth adaptation to environmental conditions in Drosophila. Cell Mol Life Sci 2020; 77:4523-4551. [PMID: 32448994 PMCID: PMC7599194 DOI: 10.1007/s00018-020-03547-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 04/19/2020] [Accepted: 05/11/2020] [Indexed: 02/07/2023]
Abstract
Organisms adapt to changing environments by adjusting their development, metabolism, and behavior to improve their chances of survival and reproduction. To achieve such flexibility, organisms must be able to sense and respond to changes in external environmental conditions and their internal state. Metabolic adaptation in response to altered nutrient availability is key to maintaining energy homeostasis and sustaining developmental growth. Furthermore, environmental variables exert major influences on growth and final adult body size in animals. This developmental plasticity depends on adaptive responses to internal state and external cues that are essential for developmental processes. Genetic studies have shown that the fruit fly Drosophila, similarly to mammals, regulates its metabolism, growth, and behavior in response to the environment through several key hormones including insulin, peptides with glucagon-like function, and steroid hormones. Here we review emerging evidence showing that various environmental cues and internal conditions are sensed in different organs that, via inter-organ communication, relay information to neuroendocrine centers that control insulin and steroid signaling. This review focuses on endocrine regulation of development, metabolism, and behavior in Drosophila, highlighting recent advances in the role of the neuroendocrine system as a signaling hub that integrates environmental inputs and drives adaptive responses.
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Affiliation(s)
- Takashi Koyama
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Michael J Texada
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kenneth A Halberg
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kim Rewitz
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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8
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Maurer GW, Malita A, Nagy S, Koyama T, Werge TM, Halberg KA, Texada MJ, Rewitz K. Analysis of genes within the schizophrenia-linked 22q11.2 deletion identifies interaction of night owl/LZTR1 and NF1 in GABAergic sleep control. PLoS Genet 2020; 16:e1008727. [PMID: 32339168 PMCID: PMC7205319 DOI: 10.1371/journal.pgen.1008727] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 05/07/2020] [Accepted: 03/20/2020] [Indexed: 12/14/2022] Open
Abstract
The human 22q11.2 chromosomal deletion is one of the strongest identified genetic risk factors for schizophrenia. Although the deletion spans a number of known genes, the contribution of each of these to the 22q11.2 deletion syndrome (DS) is not known. To investigate the effect of individual genes within this interval on the pathophysiology associated with the deletion, we analyzed their role in sleep, a behavior affected in virtually all psychiatric disorders, including the 22q11.2 DS. We identified the gene LZTR1 (night owl, nowl) as a regulator of night-time sleep in Drosophila. In humans, LZTR1 has been associated with Ras-dependent neurological diseases also caused by Neurofibromin-1 (Nf1) deficiency. We show that Nf1 loss leads to a night-time sleep phenotype nearly identical to that of nowl loss and that nowl negatively regulates Ras and interacts with Nf1 in sleep regulation. Furthermore, nowl is required for metabolic homeostasis, suggesting that LZTR1 may contribute to the genetic susceptibility to obesity associated with the 22q11.2 DS. Knockdown of nowl or Nf1 in GABA-responsive sleep-promoting neurons elicits the sleep phenotype, and this defect can be rescued by increased GABAA receptor signaling, indicating that Nowl regulates sleep through modulation of GABA signaling. Our results suggest that nowl/LZTR1 may be a conserved regulator of GABA signaling important for normal sleep that contributes to the 22q11.2 DS. Schizophrenia is a devastating mental disorder with a large genetic component to disease predisposition. One of the strongest genetic risk factors for this disorder is a relatively small genetic deletion of 43 genes on the 22nd chromosome, called 22q11.2, which confers about a 25% risk of schizophrenia development. However, it is likely that only some of these deleted genes affect disease risk, so we tested most of them individually. One of the main symptoms of schizophrenia is disturbed sleep. Sleep is an evolutionarily conserved behavior that can be easily studied in the fruit fly Drosophila melanogaster, so we investigated the effect on sleep of blocking expression of the fly homologs of most of the 22q11.2 genes and identified the gene LZTR1 (night owl, nowl) as an important sleep regulator. We found that Nowl/LZTR1 is required for inhibition of the Ras pathway and interacts genetically with the Ras inhibitor NF1. Nowl/LZTR1 appears to function in sleep by modulating inhibitory GABA signaling, which is affected in schizophrenia. Thus, this gene may underlie some of the phenotypes of the human schizophrenia-risk deletion.
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Affiliation(s)
- Gianna W. Maurer
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Alina Malita
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Stanislav Nagy
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Takashi Koyama
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas M. Werge
- Institute for Biological Psychiatry, Mental Health Centre Sct. Hans, Roskilde, Denmark
| | | | - Michael J. Texada
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kim Rewitz
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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Hill VM, O’Connor RM, Shirasu-Hiza M. Tired and stressed: Examining the need for sleep. Eur J Neurosci 2020; 51:494-508. [PMID: 30295966 PMCID: PMC6453762 DOI: 10.1111/ejn.14197] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 09/04/2018] [Accepted: 09/18/2018] [Indexed: 12/31/2022]
Abstract
A key feature of circadian rhythms is the sleep/wake cycle. Sleep causes reduced responsiveness to the environment, which puts animals in a particularly vulnerable state; yet sleep has been conserved throughout evolution, indicating that it fulfils a vital purpose. A core function of sleep across species has not been identified, but substantial advances in sleep research have been made in recent years using the genetically tractable model organism, Drosophila melanogaster. This review describes the universality of sleep, the regulation of sleep, and current theories on the function of sleep, highlighting a historical and often overlooked theory called the Free Radical Flux Theory of Sleep. Additionally, we summarize our recent work with short-sleeping Drosophila mutants and other genetic and pharmacological tools for manipulating sleep which supports an antioxidant theory of sleep and demonstrates a bi-directional relationship between sleep and oxidative stress.
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Affiliation(s)
- Vanessa M. Hill
- Department of Genetics and Development; Columbia University Medical Center; NY, NY, 10032; USA
| | - Reed M. O’Connor
- Department of Genetics and Development; Columbia University Medical Center; NY, NY, 10032; USA
| | - Mimi Shirasu-Hiza
- Department of Genetics and Development; Columbia University Medical Center; NY, NY, 10032; USA
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10
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González-Gutiérrez A, Ibacache A, Esparza A, Barros LF, Sierralta J. Neuronal lactate levels depend on glia-derived lactate during high brain activity in Drosophila. Glia 2019; 68:1213-1227. [PMID: 31876077 DOI: 10.1002/glia.23772] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/10/2019] [Accepted: 12/10/2019] [Indexed: 01/13/2023]
Abstract
Lactate/pyruvate transport between glial cells and neurons is thought to play an important role in how brain cells sustain the high-energy demand that neuronal activity requires. However, the in vivo mechanisms and characteristics that underlie the transport of monocarboxylates are poorly described. Here, we use Drosophila expressing genetically encoded FRET sensors to provide an ex vivo characterization of the transport of monocarboxylates in motor neurons and glial cells from the larval ventral nerve cord. We show that lactate/pyruvate transport in glial cells is coupled to protons and is more efficient than in neurons. Glial cells maintain higher levels of intracellular lactate generating a positive gradient toward neurons. Interestingly, during high neuronal activity, raised lactate in motor neurons is dependent on transfer from glial cells mediated in part by the previously described monocarboxylate transporter Chaski, providing support for in vivo glia-to-neuron lactate shuttling during neuronal activity.
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Affiliation(s)
- Andrés González-Gutiérrez
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Andrés Ibacache
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Andrés Esparza
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | | | - Jimena Sierralta
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
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11
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Abstract
The cellular mechanisms governing the expression, regulation, and function of sleep are not entirely understood. The traditional view is that these mechanisms are neuronal. An alternative view is that glial brain cells may play important roles in these processes. Their ubiquity in the central nervous system makes them well positioned to modulate neuronal circuits that gate sleep and wake. Their ability to respond to chemical neuronal signals suggests that they form feedback loops with neurons that may globally regulate neuronal activity. Their potential role in detoxifying the brain, regulating neuronal metabolism, and promoting synaptic plasticity raises the intriguing possibility that glia mediate important functions ascribed to sleep.
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Affiliation(s)
- Marcos G Frank
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University Spokane, Spokane, WA, USA.
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12
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Abstract
Sleep is a highly conserved phenomenon in endotherms, and therefore it must serve at least one basic function across this wide range of species. What that function is remains one of the biggest mysteries in neurobiology. By using the word neurobiology, we do not mean to exclude possible non-neural functions of sleep, but it is difficult to imagine why the brain must be taken offline if the basic function of sleep did not involve the nervous system. In this chapter we discuss several current hypotheses about sleep function. We divide these hypotheses into two categories: ones that propose higher-order cognitive functions and ones that focus on housekeeping or restorative processes. We also pose four aspects of sleep that any successful functional hypothesis has to account for: why do the properties of sleep change across the life span? Why and how is sleep homeostatically regulated? Why must the brain be taken offline to accomplish the proposed function? And, why are there two radically different stages of sleep?The higher-order cognitive function hypotheses we discuss are essential mechanisms of learning and memory and synaptic plasticity. These are not mutually exclusive hypotheses. Each focuses on specific mechanistic aspects of sleep, and higher-order cognitive processes are likely to involve components of all of these mechanisms. The restorative hypotheses are maintenance of brain energy metabolism, macromolecular biosynthesis, and removal of metabolic waste. Although these three hypotheses seem more different than those related to higher cognitive function, they may each contribute important components to a basic sleep function. Any sleep function will involve specific gene expression and macromolecular biosynthesis, and as we explain there may be important connections between brain energy metabolism and the need to remove metabolic wastes.A deeper understanding of sleep functions in endotherms will enable us to answer whether or not rest behaviors in species other than endotherms are homologous with mammalian and avian sleep. Currently comparisons across the animal kingdom depend on superficial and phenomenological features of rest states and sleep, but investigations of sleep functions would provide more insight into the evolutionary relationships between EEG-defined sleep in endotherms and rest states in ectotherms.
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Affiliation(s)
- Marcos G Frank
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University Spokane, Spokane, WA, USA
| | - H Craig Heller
- Department of Biology, Stanford University, Stanford, CA, USA.
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13
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Nagy S, Maurer GW, Hentze JL, Rose M, Werge TM, Rewitz K. AMPK signaling linked to the schizophrenia-associated 1q21.1 deletion is required for neuronal and sleep maintenance. PLoS Genet 2018; 14:e1007623. [PMID: 30566533 PMCID: PMC6317821 DOI: 10.1371/journal.pgen.1007623] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 01/03/2019] [Accepted: 11/20/2018] [Indexed: 12/31/2022] Open
Abstract
The human 1q21.1 deletion of ten genes is associated with increased risk of schizophrenia. This deletion involves the β-subunit of the AMP-activated protein kinase (AMPK) complex, a key energy sensor in the cell. Although neurons have a high demand for energy and low capacity to store nutrients, the role of AMPK in neuronal physiology is poorly defined. Here we show that AMPK is important in the nervous system for maintaining neuronal integrity and for stress survival and longevity in Drosophila. To understand the impact of this signaling system on behavior and its potential contribution to the 1q21.1 deletion syndrome, we focused on sleep, an important role of which is proposed to be the reestablishment of neuronal energy levels that are diminished during energy-demanding wakefulness. Sleep disturbances are one of the most common problems affecting individuals with psychiatric disorders. We show that AMPK is required for maintenance of proper sleep architecture and for sleep recovery following sleep deprivation. Neuronal AMPKβ loss specifically leads to sleep fragmentation and causes dysregulation of genes believed to play a role in sleep homeostasis. Our data also suggest that AMPKβ loss may contribute to the increased risk of developing mental disorders and sleep disturbances associated with the human 1q21.1 deletion. The human 1q21.1 chromosomal deletion is associated with increased risk of schizophrenia. Because this deletion affects only a small number of genes, it provides a unique opportunity to identify the specific disease-causing gene(s) using animal models. Here, we report the use of a Drosophila model to identify the potential contribution of one gene affected by the 1q21.1 deletion–PRKAB2 –to the pathology of the 1q21.1 deletion syndrome. PRKAB2 encodes a subunit of the AMP-activated protein kinase (AMPK) complex, the main cellular energy sensor. We show that AMPK deficiency reduces lifespan and causes structural abnormalities in neuronal dendritic structures, a phenotype which has been linked to schizophrenia. Furthermore, cognitive impairment and altered sleep patterning are some of the most common symptoms of schizophrenia. Therefore, to understand the potential contribution of PRKAB2 to the 1q21.1 syndrome, we tested whether AMPK alterations might cause defects in learning and sleep. Our studies show that lack of PRKAB2 and AMPK-complex activity in the nervous system leads to reduced learning and to dramatic sleep disturbances. Thus, our data links a single 1q21.1-related gene with phenotypes that resemble common symptoms of neuropsychiatric disorders, suggesting that this gene, PRKAB2, may contribute to the risk of developing schizophrenia.
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Affiliation(s)
- Stanislav Nagy
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Gianna W Maurer
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Julie L Hentze
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Institute for Biological Psychiatry, Mental Health Centre Sct. Hans, Roskilde, Denmark.,Department of Pathology, Herlev Hospital, Herlev, Denmark
| | - Morten Rose
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas M Werge
- Institute for Biological Psychiatry, Mental Health Centre Sct. Hans, Roskilde, Denmark
| | - Kim Rewitz
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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14
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Bellesi M, de Vivo L, Koebe S, Tononi G, Cirelli C. Sleep and Wake Affect Glycogen Content and Turnover at Perisynaptic Astrocytic Processes. Front Cell Neurosci 2018; 12:308. [PMID: 30254569 PMCID: PMC6141665 DOI: 10.3389/fncel.2018.00308] [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: 06/08/2018] [Accepted: 08/23/2018] [Indexed: 12/26/2022] Open
Abstract
Astrocytic glycogen represents the only form of glucose storage in the brain, and one of the outcomes of its breakdown is the production of lactate that can be used by neurons as an alternative energetic substrate. Since brain metabolism is higher in wake than in sleep, it was hypothesized that glycogen stores are depleted during wake and replenished during sleep. Furthermore, it was proposed that glycogen depletion leads to the progressive increase in adenosine levels during wake, providing a homeostatic signal that reflects the buildup of sleep pressure. However, previous studies that measured glycogen dynamics across the sleep/wake cycle obtained inconsistent results, and only measured glycogen in whole tissue. Since most energy in the brain is used to sustain synaptic activity, here we employed tridimensional electron microscopy to quantify glycogen content in the astrocytic processes surrounding the synapse. We studied axon-spine synapses in the frontal cortex of young mice after ~7 h of sleep, 7–8 h of spontaneous or forced wake, or 4.5 days of sleep restriction. Relative to sleep, all wake conditions increased the number of glycogen granules around the synapses to a similar extent. However, progressively longer periods of wake were associated with progressively smaller glycogen granules, suggesting increased turnover. Despite the increased number of granules, in all wake conditions the estimated amount of glucose within the granules was lower than in sleep, indicating that sleep may favor glucose storage. Finally, chronic sleep restriction moved glycogen granules closer to the synaptic cleft. Thus, both short and long wake lead to increased glycogen turnover around cortical synapses, whereas sleep promotes glycogen accumulation.
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Affiliation(s)
- Michele Bellesi
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, United States.,Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Università Politecnica delle Marche, Ancona, Italy
| | - Luisa de Vivo
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, United States
| | - Samuel Koebe
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, United States
| | - Giulio Tononi
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, United States
| | - Chiara Cirelli
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, United States
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15
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Shah AK, Kreibich CD, Amdam GV, Münch D. Metabolic enzymes in glial cells of the honeybee brain and their associations with aging, starvation and food response. PLoS One 2018; 13:e0198322. [PMID: 29927967 PMCID: PMC6013123 DOI: 10.1371/journal.pone.0198322] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 05/17/2018] [Indexed: 12/03/2022] Open
Abstract
The honey bee has been extensively studied as a model for neuronal circuit and memory function and more recently has emerged as an unconventional model in biogerontology. Yet, the detailed knowledge of neuronal processing in the honey bee brain contrasts with the very sparse information available on glial cells. In other systems glial cells are involved in nutritional homeostasis, detoxification, and aging. These glial functions have been linked to metabolic enzymes, such as glutamine synthetase and glycogen phosphorylase. As a step in identifying functional roles and potential differences among honey bee glial types, we examined the spatial distribution of these enzymes and asked if enzyme abundance is associated with aging and other processes essential for survival. Using immunohistochemistry and confocal laser microscopy we demonstrate that glutamine synthetase and glycogen phosphorylase are abundant in glia but appear to co-localize with different glial sub-types. The overall spatial distribution of both enzymes was not homogenous and differed markedly between different neuropiles and also within each neuropil. Using semi-quantitative Western blotting we found that rapid aging, typically observed in shortest-lived worker bees (foragers), was associated with declining enzyme levels. Further, we found enzyme abundance changes after severe starvation stress, and that glutamine synthetase is associated with food response. Together, our data indicate that aging and nutritional physiology in bees are linked to glial specific metabolic enzymes. Enzyme specific localization patterns suggest a functional differentiation among identified glial types.
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Affiliation(s)
- Ashish K. Shah
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Claus D. Kreibich
- Faculty of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Aas, Norway
| | - Gro V. Amdam
- Faculty of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Aas, Norway
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Daniel Münch
- Faculty of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Aas, Norway
- * E-mail:
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16
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Yamada T, Habara O, Kubo H, Nishimura T. Fat body glycogen serves as a metabolic safeguard for the maintenance of sugar levels in Drosophila. Development 2018; 145:dev.158865. [DOI: 10.1242/dev.158865] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 02/09/2018] [Indexed: 12/26/2022]
Abstract
Adapting to changes in food availability is a central challenge for survival. Glucose is an important resource for energy production, and therefore, many organisms synthesize and retain sugar storage molecules. In insects, glucose is stored in two different forms: the disaccharide trehalose and the branched polymer glycogen. Glycogen is synthesized and stored in several tissues, including in muscle and the fat body. Despite the important role of the fat body as a center for energy metabolism, the importance of its glycogen content remains unclear. Here, we show that glycogen metabolism is regulated in a tissue-specific manner under starvation conditions in the fruit fly Drosophila. The mobilization of fat body glycogen in larvae is independent of adipokinetic hormone (Akh, the glucagon homolog) but is regulated by sugar availability in a tissue-autonomous manner. Fat body glycogen plays a critical role in the maintenance of circulating sugars, including trehalose, under fasting conditions. These results demonstrate the importance of fat body glycogen as a metabolic safeguard in Drosophila.
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Affiliation(s)
- Takayuki Yamada
- Laboratory for Growth Control Signaling, RIKEN Center for Developmental Biology (CDB), 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Okiko Habara
- Laboratory for Growth Control Signaling, RIKEN Center for Developmental Biology (CDB), 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Hitomi Kubo
- Laboratory for Growth Control Signaling, RIKEN Center for Developmental Biology (CDB), 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Takashi Nishimura
- Laboratory for Growth Control Signaling, RIKEN Center for Developmental Biology (CDB), 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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17
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Rittschof CC, Schirmeier S. Insect models of central nervous system energy metabolism and its links to behavior. Glia 2017; 66:1160-1175. [DOI: 10.1002/glia.23235] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/30/2017] [Accepted: 09/08/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Clare C. Rittschof
- Department of Entomology; College of Agriculture, Food, and the Environment, University of Kentucky; Lexington Kentucky
| | - Stefanie Schirmeier
- Institut für Neuro-und Verhaltensbiologie, University of Münster; Münster Germany
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18
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Winwood-Smith HS, Franklin CE, White CR. Low-carbohydrate diet induces metabolic depression: a possible mechanism to conserve glycogen. Am J Physiol Regul Integr Comp Physiol 2017; 313:R347-R356. [PMID: 28701319 DOI: 10.1152/ajpregu.00067.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/05/2017] [Accepted: 07/05/2017] [Indexed: 01/14/2023]
Abstract
Long-term studies have found that low-carbohydrate diets are more effective for weight loss than calorie-restricted diets in the short term but equally or only marginally more effective in the long term. Low-carbohydrate diets have been linked to reduced glycogen stores and increased feelings of fatigue. We propose that reduced physical activity in response to lowered glycogen explains the diminishing weight loss advantage of low-carbohydrate compared with low-calorie diets over longer time periods. We explored this possibility by feeding adult Drosophila melanogaster a standard or a low-carbohydrate diet for 9 days and measured changes in metabolic rate, glycogen stores, activity, and body mass. We hypothesized that a low-carbohydrate diet would cause a reduction in glycogen stores, which recover over time, a reduction in physical activity, and an increase in resting metabolic rate. The low-carbohydrate diet reduced glycogen stores, which recovered over time. Activity was unaffected by diet, but metabolic rate was reduced, in the low-carbohydrate group. We conclude that metabolic depression could explain the decreased effectiveness of low-carbohydrate diets over time and recommend further investigation of long-term metabolic effects of dietary interventions and a greater focus on physiological plasticity within the study of human nutrition.
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Affiliation(s)
- Hugh S Winwood-Smith
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia; and
| | - Craig E Franklin
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia; and
| | - Craig R White
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
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19
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Krueger JM, Frank MG, Wisor JP, Roy S. Sleep function: Toward elucidating an enigma. Sleep Med Rev 2016; 28:46-54. [PMID: 26447948 PMCID: PMC4769986 DOI: 10.1016/j.smrv.2015.08.005] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 07/16/2015] [Accepted: 08/19/2015] [Indexed: 01/11/2023]
Abstract
Sleep function remains controversial. Individual perspectives frame the issue of sleep function differently. We briefly illustrate how sleep measurement and the evolution, tissue organization levels, molecular mechanisms, and regulation of sleep could influence one's view of sleep function. Then we discuss six viable theories of sleep function. Sleep serves host-defense mechanisms and conserves caloric expenditures, but these functions likely are opportunistic functions evolving later in evolution. That sleep replenishes brain energy stores and that sleep serves a glymphatic function by removing toxic byproducts of waking activity are attractive ideas, but lack extensive supporting experimental evidence. That sleep restores performance is experimentally demonstrated and has obvious evolutionary value. However, this hypothesis lacks experimentally verified mechanisms although ideas relating to this issue are presented. Finally, the ideas surrounding the broad hypothesis that sleep serves a connectivity/plasticity function are many and attractive. There is experimental evidence that connectivity changes with sleep, sleep loss, and with changing afferent input, and that those changes are linked to sleep regulatory mechanisms. In our view, this is the leading contender for the primordial function of sleep. However, much refinement of ideas and innovative experimental approaches are needed to clarify the sleep-connectivity relationship.
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Affiliation(s)
- James M Krueger
- College of Medical Sciences, Washington State University-Spokane, WA, USA.
| | - Marcos G Frank
- College of Medical Sciences, Washington State University-Spokane, WA, USA
| | - Jonathan P Wisor
- College of Medical Sciences, Washington State University-Spokane, WA, USA
| | - Sandip Roy
- Department of Electrical Engineering, Washington State University-Pullman, WA, USA
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20
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Petit JM, Burlet-Godinot S, Magistretti PJ, Allaman I. Glycogen metabolism and the homeostatic regulation of sleep. Metab Brain Dis 2015; 30:263-79. [PMID: 25399336 PMCID: PMC4544655 DOI: 10.1007/s11011-014-9629-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 11/04/2014] [Indexed: 12/19/2022]
Abstract
In 1995 Benington and Heller formulated an energy hypothesis of sleep centered on a key role of glycogen. It was postulated that a major function of sleep is to replenish glycogen stores in the brain that have been depleted during wakefulness which is associated to an increased energy demand. Astrocytic glycogen depletion participates to an increase of extracellular adenosine release which influences sleep homeostasis. Here, we will review some evidence obtained by studies addressing the question of a key role played by glycogen metabolism in sleep regulation as proposed by this hypothesis or by an alternative hypothesis named "glycogenetic" hypothesis as well as the importance of the confounding effect of glucocorticoïds. Even though actual collected data argue in favor of a role of sleep in brain energy balance-homeostasis, they do not support a critical and direct involvement of glycogen metabolism on sleep regulation. For instance, glycogen levels during the sleep-wake cycle are driven by different physiological signals and therefore appear more as a marker-integrator of brain energy status than a direct regulator of sleep homeostasis. In support of this we provide evidence that blockade of glycogen mobilization does not induce more sleep episodes during the active period while locomotor activity is reduced. These observations do not invalidate the energy hypothesis of sleep but indicate that underlying cellular mechanisms are more complex than postulated by Benington and Heller.
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Affiliation(s)
- Jean-Marie Petit
- Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland,
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21
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Volgin DV, Lu JW, Stettner GM, Mann GL, Ross RJ, Morrison AR, Kubin L. Time- and behavioral state-dependent changes in posterior hypothalamic GABAA receptors contribute to the regulation of sleep. PLoS One 2014; 9:e86545. [PMID: 24466145 PMCID: PMC3897747 DOI: 10.1371/journal.pone.0086545] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/11/2013] [Indexed: 12/17/2022] Open
Abstract
Sleep-wake behavior is regulated by a circadian rhythm, homeostatically and by additional mechanisms that determine the timing of slow-wave sleep and rapid eye movement sleep (REMS) episodes. The posterior hypothalamus coordinates the neural and humoral signals with the rest-activity cycle. It contains wake-active neurons, and is a site where stimulation of inhibitory GABAA receptors promotes sleep, whereas their antagonism enhances wakefulness. We explored whether GABAergic mechanisms present in the posterior hypothalamus contribute to the homeostatic and other aspects of sleep-wake regulation. Using micropunches of tissue extracted from either the perifornical (PF) or dorsomedial (DM) regions of the posterior hypothalamus of rats, we determined that mRNA levels for selected subunits of GABAA receptors (β1, β3 and ε) were higher at the end of the active period or following sleep deprivation, when the need for sleep is high, than after several hours of sleep, when sleep need is partially fulfilled. Such a pattern was present in the PF region only, and was consistent with changes in β1 subunit and GABA synthesizing enzyme (GAD) protein levels. In contrast, in the DM region, the levels of GABAA receptor subunit mRNAs and proteins (α1, α2, β1) and GAD varied with circadian time, but were not responsive to sleep deprivation. Separate experiments with sleep-wake monitoring and local perfusion of the PF region with the GABAA receptor antagonist bicuculline revealed that the antagonist had a weaker sleep-reducing effect when sleep need was enhanced by sleep deprivation and that the increased amount of REMS characteristic of the late sleep period was dependent on endogenous GABAergic inhibition. These results support the concept that a varying magnitude of GABAergic inhibition exerted within the PF region contributes to the homeostatic regulation of sleep and shapes its temporal pattern, whereas GABAergic mechanisms in the DM region contribute to circadian regulation.
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Affiliation(s)
- Denys V. Volgin
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jackie W. Lu
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Georg M. Stettner
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Graziella L. Mann
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Richard J. Ross
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Psychiatry, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Behavioral Health Service, Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania, United States of America
| | - Adrian R. Morrison
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Leszek Kubin
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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22
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Potdar S, Sheeba V. Lessons From Sleeping Flies: Insights fromDrosophila melanogasteron the Neuronal Circuitry and Importance of Sleep. J Neurogenet 2013; 27:23-42. [DOI: 10.3109/01677063.2013.791692] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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23
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Frank MG. Astroglial regulation of sleep homeostasis. Curr Opin Neurobiol 2013; 23:812-8. [PMID: 23518138 DOI: 10.1016/j.conb.2013.02.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 02/20/2013] [Accepted: 02/21/2013] [Indexed: 12/12/2022]
Abstract
Mammalian sleep is regulated by two distinct mechanisms. A circadian oscillator provides timing signals that organize sleep and wake across the 24 hour day. A homeostatic mechanism increases sleep drive and sleep amounts (or intensity) as a function of prior time awake. The cellular mechanisms of sleep homeostasis are poorly defined, but are thought to be primarily neuronal. According to one view, sleep homeostasis arises from interactions between subcortical neurons that register sleep pressure and other neurons that promote either sleep or wakefulness. Alternatively, sleep drive may arise independently among neurons throughout the brain in a use-dependent fashion. Implicit in both views is the idea that sleep homeostasis is solely the product of neurons. In this article, I discuss an emerging view that glial astrocytes may play an essential role in sleep homeostasis.
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Affiliation(s)
- Marcos G Frank
- University of Pennsylvania, Perelman School of Medicine, Department of Neuroscience, 215 Stemmler Hall, 35th & Hamilton Walk, Philadelphia, PA 19104-6074, United States.
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24
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Affiliation(s)
- David M Raizen
- Department of Neurology, University of Pennsylvania School of Medicine
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25
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Energy stores are not altered by long-term partial sleep deprivation in Drosophila melanogaster. PLoS One 2009; 4:e6211. [PMID: 19593430 PMCID: PMC2703806 DOI: 10.1371/journal.pone.0006211] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Accepted: 06/13/2009] [Indexed: 11/19/2022] Open
Abstract
Recent human studies reveal a widespread association between short sleep and obesity. Two hypotheses, which are not mutually exclusive, might explain this association. First, genetic factors that reduce endogenous sleep times might also impact energy stores, an assertion that we confirmed in a previous study. Second, metabolism may be altered by chronic partial sleep deprivation. Here we address the second assertion by measuring the impact of long-term partial sleep deprivation on energy stores using Drosophila as a model. We subjected flies to long-term partial sleep deprivation via two different methods: a mechanical stimulus and a light stimulus. We then measured whole-body triglycerides and glycogen, two important sources of energy for the fly, and compared them to un-stimulated controls. We also measured changes in energy stores in response to a random circadian clock shift. Sex and line-dependent alterations in glycogen and/or triglyceride levels occurred in response to the circadian clock shift and in flies subjected to a single night of sleep deprivation using light. Thus, consistent with previous studies, our findings suggest that acute sleep loss and changes to the circadian clock can alter metabolism. Significant changes in energy stores were also observed when flies were subjected to chronic sleep loss via the mechanical stimulus, although not the light stimulus. Interestingly, mechanical stimulation resulted in the same change in energy stores even when it was not associated with sleep deprivation, suggesting that the changes are caused by stress rather than sleep loss. These findings emphasize the importance of taking stress into account when evaluating the relationship between sleep loss and metabolism.
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26
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Scharf MT, Naidoo N, Zimmerman JE, Pack AI. The energy hypothesis of sleep revisited. Prog Neurobiol 2008; 86:264-80. [PMID: 18809461 DOI: 10.1016/j.pneurobio.2008.08.003] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 06/08/2008] [Accepted: 08/27/2008] [Indexed: 01/09/2023]
Abstract
One of the proposed functions of sleep is to replenish energy stores in the brain that have been depleted during wakefulness. Benington and Heller formulated a version of the energy hypothesis of sleep in terms of the metabolites adenosine and glycogen. They postulated that during wakefulness, adenosine increases and astrocytic glycogen decreases reflecting the increased energetic demand of wakefulness. We review recent studies on adenosine and glycogen stimulated by this hypothesis. We also discuss other evidence that wakefulness is an energetic challenge to the brain including the unfolded protein response, the electron transport chain, NPAS2, AMP-activated protein kinase, the astrocyte-neuron lactate shuttle, production of reactive oxygen species and uncoupling proteins. We believe the available evidence supports the notion that wakefulness is an energetic challenge to the brain, and that sleep restores energy balance in the brain, although the mechanisms by which this is accomplished are considerably more complex than envisaged by Benington and Heller.
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Affiliation(s)
- Matthew T Scharf
- Center for Sleep and Respiratory Neurobiology, University of Pennsylvania School of Medicine, Translational Research Building, Suite 2100, 125 S. 31st Street, Philadelphia, PA 19104-3403, USA.
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27
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Gailliot MT. Unlocking the Energy Dynamics of Executive Functioning: Linking Executive Functioning to Brain Glycogen. PERSPECTIVES ON PSYCHOLOGICAL SCIENCE 2008; 3:245-63. [DOI: 10.1111/j.1745-6924.2008.00077.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Past work suggests that executive functioning relies on glucose as a depletable energy, such that executive functioning uses a relatively large amount of glucose and is impaired when glucose is low. Glucose from the bloodstream is one energy source for the brain, and glucose stored in the brain as glycogen is another. A review of the literature on glycogen suggests that executive functioning uses it in much the same way as glucose, such that executive functioning uses glycogen and is impaired when glycogen is low. Findings on stress, physical persistence, glucose tolerance, diabetes, sleep, heat, and other topics provide general support for this view.
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28
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Abstract
Although intensively studied, the biological purpose of sleep is not known. To identify candidate genes affecting sleep, we assayed 136 isogenic P-element insertion lines of Drosophila melanogaster. Since sleep has been negatively correlated with energy reserves across taxa, we measured energy stores (whole-body protein, glycogen, and triglycerides) in these lines as well. Twenty-one insertions with known effects on physiology, development, and behavior affect 24-hr sleep time. Thirty-two candidate insertions significantly impact energy stores. Mutational genetic correlations among sleep parameters revealed that the genetic basis of the transition between sleep and waking states in males and females may be different. Furthermore, sleep bout number can be decoupled from waking activity in males, but not in females. Significant genetic correlations are present between sleep phenotypes and glycogen stores in males, while sleep phenotypes are correlated with triglycerides in females. Differences observed in male and female sleep behavior in flies may therefore be related to sex-specific differences in metabolic needs. Sleep thus emerges as a complex trait that exhibits extensive pleiotropy and sex specificity. The large mutational target that we observed implicates genes functioning in a variety of biological processes, suggesting that sleep may serve a number of different functions rather than a single purpose.
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29
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Tu BP, McKnight SL. Metabolic cycles as an underlying basis of biological oscillations. Nat Rev Mol Cell Biol 2006; 7:696-701. [PMID: 16823381 DOI: 10.1038/nrm1980] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The evolutionary origins of periodic phenomena in biology, such as the circadian cycle, the hibernation cycle and the sleep-wake cycle, remain a mystery. We discuss the concept of temporal compartmentalization of metabolism that takes place during such cycles, and suggest that cyclic changes in a cell's metabolic state might be a fundamental driving force for such biological oscillations.
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Affiliation(s)
- Benjamin P Tu
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390, USA.
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30
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Franken P, Gip P, Hagiwara G, Ruby NF, Heller HC. Glycogen content in the cerebral cortex increases with sleep loss in C57BL/6J mice. Neurosci Lett 2006; 402:176-9. [PMID: 16644123 DOI: 10.1016/j.neulet.2006.03.072] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Accepted: 03/31/2006] [Indexed: 11/29/2022]
Abstract
We hypothesized that a function of sleep is to replenish brain glycogen stores that become depleted while awake. We have previously tested this hypothesis in three inbred strains of mice by measuring brain glycogen after a 6h sleep deprivation (SD). Unexpectedly, glycogen content in the cerebral cortex did not decrease with SD in two of the strains and was even found to increase in mice of the C57BL/6J (B6) strain. Manipulations that initially induce glycogenolysis can also induce subsequent glycogen synthesis thereby elevating glycogen content beyond baseline. It is thus possible that in B6 mice, cortical glycogen content decreased early during SD and became elevated later in SD. In the present study, we therefore measured changes in brain glycogen over the course of a 6 h SD and during recovery sleep in B6 mice. We found no evidence of a decrease at any time during the SD, instead, cortical glycogen content monotonically increased with time-spent-awake and, when sleep was allowed, started to revert to control levels. Such a time-course is opposite to the one predicted by our initial hypothesis. These results demonstrate that glycogen synthesis can be achieved during prolonged wakefulness to the extent that it outweighs glycogenolysis. Maintaining this energy store seems thus not to be functionally related to sleep in this strain.
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Affiliation(s)
- Paul Franken
- Department of Biological Sciences, Stanford University, Stanford, CA, USA.
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Abstract
The functions of mammalian sleep remain unclear. Most theories suggest a role for non-rapid eye movement (NREM) sleep in energy conservation and in nervous system recuperation. Theories of REM sleep have suggested a role for this state in periodic brain activation during sleep, in localized recuperative processes and in emotional regulation. Across mammals, the amount and nature of sleep are correlated with age, body size and ecological variables, such as whether the animals live in a terrestrial or an aquatic environment, their diet and the safety of their sleeping site. Sleep may be an efficient time for the completion of a number of functions, but variations in sleep expression indicate that these functions may differ across species.
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Affiliation(s)
- Jerome M Siegel
- Neurobiology Research 151A3, VA GLAHS Sepulveda, Department of Psychiatry and Brain Research Institute, UCLA School of Medicine, North Hills, California 91343, USA.
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