1
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Meyerhof GT, Easwaran S, Bontempo AE, Montell C, Montell DJ. Altered circadian rhythm, sleep, and rhodopsin 7-dependent shade preference during diapause in Drosophila melanogaster. Proc Natl Acad Sci U S A 2024; 121:e2400964121. [PMID: 38917005 PMCID: PMC11228485 DOI: 10.1073/pnas.2400964121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 05/22/2024] [Indexed: 06/27/2024] Open
Abstract
To survive adverse environments, many animals enter a dormant state such as hibernation, dauer, or diapause. Various Drosophila species undergo adult reproductive diapause in response to cool temperatures and/or short day-length. While flies are less active during diapause, it is unclear how adverse environmental conditions affect circadian rhythms and sleep. Here we show that in diapause-inducing cool temperatures, Drosophila melanogaster exhibit altered circadian activity profiles, including severely reduced morning activity and an advanced evening activity peak. Consequently, the flies have a single activity peak at a time similar to when nondiapausing flies take a siesta. Temperatures ≤15 °C, rather than photoperiod, primarily drive this behavior. At cool temperatures, flies rapidly enter a deep-sleep state that lacks the sleep cycles of flies at higher temperatures and require high levels of stimulation for arousal. Furthermore, we show that at 25 °C, flies prefer to siesta in the shade, a preference that is virtually eliminated at 10 °C. Resting in the shade is driven by an aversion to blue light that is sensed by Rhodopsin 7 outside of the eyes. Flies at 10 °C show neuronal markers of elevated sleep pressure, including increased expression of Bruchpilot and elevated Ca2+ in the R5 ellipsoid body neurons. Therefore, sleep pressure might overcome blue light aversion. Thus, at the same temperatures that cause reproductive arrest, preserve germline stem cells, and extend lifespan, D. melanogaster are prone to deep sleep and exhibit dramatically altered, yet rhythmic, daily activity patterns.
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Affiliation(s)
- Geoff T. Meyerhof
- Department of Molecular, Cellular, and Developmental Biology, Santa Barbara, CA93106
- Neuroscience Research Institute, University of California, Santa Barbara, CA93106
| | - Sreesankar Easwaran
- Department of Molecular, Cellular, and Developmental Biology, Santa Barbara, CA93106
- Neuroscience Research Institute, University of California, Santa Barbara, CA93106
| | - Angela E. Bontempo
- Department of Molecular, Cellular, and Developmental Biology, Santa Barbara, CA93106
- Neuroscience Research Institute, University of California, Santa Barbara, CA93106
| | - Craig Montell
- Department of Molecular, Cellular, and Developmental Biology, Santa Barbara, CA93106
- Neuroscience Research Institute, University of California, Santa Barbara, CA93106
| | - Denise J. Montell
- Department of Molecular, Cellular, and Developmental Biology, Santa Barbara, CA93106
- Neuroscience Research Institute, University of California, Santa Barbara, CA93106
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2
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Joyce M, Falconio FA, Blackhurst L, Prieto-Godino L, French AS, Gilestro GF. Divergent evolution of sleep in Drosophila species. Nat Commun 2024; 15:5091. [PMID: 38876988 PMCID: PMC11178934 DOI: 10.1038/s41467-024-49501-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 06/05/2024] [Indexed: 06/16/2024] Open
Abstract
Living organisms synchronize their biological activities with the earth's rotation through the circadian clock, a molecular mechanism that regulates biology and behavior daily. This synchronization factually maximizes positive activities (e.g., social interactions, feeding) during safe periods, and minimizes exposure to dangers (e.g., predation, darkness) typically at night. Beyond basic circadian regulation, some behaviors like sleep have an additional layer of homeostatic control, ensuring those essential activities are fulfilled. While sleep is predominantly governed by the circadian clock, a secondary homeostatic regulator, though not well-understood, ensures adherence to necessary sleep amounts and hints at a fundamental biological function of sleep beyond simple energy conservation and safety. Here we explore sleep regulation across seven Drosophila species with diverse ecological niches, revealing that while circadian-driven sleep aspects are consistent, homeostatic regulation varies significantly. The findings suggest that in Drosophilids, sleep evolved primarily for circadian purposes. The more complex, homeostatically regulated functions of sleep appear to have evolved independently in a species-specific manner, and are not universally conserved. This laboratory model may reproduce and recapitulate primordial sleep evolution.
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Affiliation(s)
- Michaela Joyce
- Department of Life Sciences, Imperial College London, London, UK
- The Francis Crick Research Institute, London, UK
| | | | | | | | - Alice S French
- Department of Life Sciences, Imperial College London, London, UK.
- The Francis Crick Research Institute, London, UK.
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK.
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3
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Yano J, Nave C, Larratt K, Honey P, Roberts M, Jingco C, Fung ML, Trotter D, He X, Elezi G, Whitelegge JP, Wasserman S, Donlea JM. Elevated sleep quota in a stress-resilient Drosophila species. Curr Biol 2024; 34:2487-2501.e3. [PMID: 38772361 PMCID: PMC11163955 DOI: 10.1016/j.cub.2024.04.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/09/2024] [Accepted: 04/25/2024] [Indexed: 05/23/2024]
Abstract
Sleep is broadly conserved across the animal kingdom but can vary widely between species. It is currently unclear which selective pressures and regulatory mechanisms influence differences in sleep between species. The fruit fly Drosophila melanogaster has become a successful model system for examining sleep regulation and function, but little is known about the sleep patterns in many related fly species. Here, we find that fly species with adaptations to extreme desert environments, including D. mojavensis, exhibit strong increases in baseline sleep compared with D. melanogaster. Long-sleeping D. mojavensis show intact homeostasis, indicating that desert flies carry an elevated drive for sleep. In addition, D. mojavensis exhibit altered abundance or distribution of several sleep/wake-related neuromodulators and neuropeptides that are consistent with their reduced locomotor activity and increased sleep. Finally, we find that in a nutrient-deprived environment, the sleep patterns of individual D. mojavensis are strongly correlated with their survival time and that disrupting sleep via constant light stimulation renders D. mojavensis more sensitive to starvation. Our results demonstrate that D. mojavensis is a novel model for studying organisms with high sleep drive and for exploring sleep strategies that provide resilience in extreme environments.
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Affiliation(s)
- Jessica Yano
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Molecular, Cellular & Integrative Physiology Interdepartmental PhD Program, UCLA, Los Angeles, CA 90095, USA
| | - Ceazar Nave
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Katherine Larratt
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Phia Honey
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Department of Neuroscience, Wellesley College, Wellesley, MA 02481, USA
| | - Makayla Roberts
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Cassandra Jingco
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Melanie L Fung
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Damion Trotter
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Molecular, Cellular & Integrative Physiology Interdepartmental PhD Program, UCLA, Los Angeles, CA 90095, USA
| | - Xin He
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Gazmend Elezi
- Pasarow Mass Spectrometry Laboratory, Jane & Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Cotsen Institute of Archaeology, UCLA, Los Angeles, CA 90095, USA
| | - Julian P Whitelegge
- Pasarow Mass Spectrometry Laboratory, Jane & Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Sara Wasserman
- Department of Neuroscience, Wellesley College, Wellesley, MA 02481, USA
| | - Jeffrey M Donlea
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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4
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Turrel O, Gao L, Sigrist SJ. Presynaptic regulators in memory formation. Learn Mem 2024; 31:a054013. [PMID: 38862173 PMCID: PMC11199941 DOI: 10.1101/lm.054013.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 04/17/2024] [Indexed: 06/13/2024]
Abstract
The intricate molecular and structural sequences guiding the formation and consolidation of memories within neuronal circuits remain largely elusive. In this study, we investigate the roles of two pivotal presynaptic regulators, the small GTPase Rab3, enriched at synaptic vesicles, and the cell adhesion protein Neurexin-1, in the formation of distinct memory phases within the Drosophila mushroom body Kenyon cells. Our findings suggest that both proteins play crucial roles in memory-supporting processes within the presynaptic terminal, operating within distinct plasticity modules. These modules likely encompass remodeling and maturation of existing active zones (AZs), as well as the formation of new AZs.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology, Genetics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Lili Gao
- Institute for Biology, Genetics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology, Genetics, Freie Universität Berlin, 14195 Berlin, Germany
- Cluster of Excellence NeuroCure, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
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5
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Suárez-Grimalt R, Grunwald Kadow IC, Scheunemann L. An integrative sensor of body states: how the mushroom body modulates behavior depending on physiological context. Learn Mem 2024; 31:a053918. [PMID: 38876486 PMCID: PMC11199956 DOI: 10.1101/lm.053918.124] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/08/2024] [Indexed: 06/16/2024]
Abstract
The brain constantly compares past and present experiences to predict the future, thereby enabling instantaneous and future behavioral adjustments. Integration of external information with the animal's current internal needs and behavioral state represents a key challenge of the nervous system. Recent advancements in dissecting the function of the Drosophila mushroom body (MB) at the single-cell level have uncovered its three-layered logic and parallel systems conveying positive and negative values during associative learning. This review explores a lesser-known role of the MB in detecting and integrating body states such as hunger, thirst, and sleep, ultimately modulating motivation and sensory-driven decisions based on the physiological state of the fly. State-dependent signals predominantly affect the activity of modulatory MB input neurons (dopaminergic, serotoninergic, and octopaminergic), but also induce plastic changes directly at the level of the MB intrinsic and output neurons. Thus, the MB emerges as a tightly regulated relay station in the insect brain, orchestrating neuroadaptations due to current internal and behavioral states leading to short- but also long-lasting changes in behavior. While these adaptations are crucial to ensure fitness and survival, recent findings also underscore how circuit motifs in the MB may reflect fundamental design principles that contribute to maladaptive behaviors such as addiction or depression-like symptoms.
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Affiliation(s)
- Raquel Suárez-Grimalt
- Institute for Biology/Genetics, Freie Universität Berlin, 14195 Berlin, Germany
- Institut für Neurophysiologie and NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | | | - Lisa Scheunemann
- Institute for Biology/Genetics, Freie Universität Berlin, 14195 Berlin, Germany
- Institut für Neurophysiologie and NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
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6
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Weiss JT, Blundell MZ, Singh P, Donlea JM. Sleep deprivation drives brain-wide changes in cholinergic presynapse abundance in Drosophila melanogaster. Proc Natl Acad Sci U S A 2024; 121:e2312664121. [PMID: 38498719 PMCID: PMC10990117 DOI: 10.1073/pnas.2312664121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 02/19/2024] [Indexed: 03/20/2024] Open
Abstract
Sleep is an evolutionarily conserved state that supports brain functions, including synaptic plasticity, in species across the animal kingdom. Here, we examine the neuroanatomical and cell-type distribution of presynaptic scaling in the fly brain after sleep loss. We previously found that sleep loss drives accumulation of the active zone scaffolding protein Bruchpilot (BRP) within cholinergic Kenyon cells of the Drosophila melanogaster mushroom body (MB), but not in other classes of MB neurons. To test whether similar cell type-specific trends in plasticity occur broadly across the brain, we used a flp-based genetic reporter to label presynaptic BRP in cholinergic, dopaminergic, GABAergic, or glutamatergic neurons. We then collected whole-brain confocal image stacks of BRP intensity to systematically quantify BRP, a marker of presynapse abundance, across 37 neuropil regions of the central fly brain. Our results indicate that sleep loss, either by overnight (12-h) mechanical stimulation or chronic sleep disruption in insomniac mutants, broadly elevates cholinergic synapse abundance across the brain, while synapse abundance in neurons that produce other neurotransmitters undergoes weaker, if any, changes. Extending sleep deprivation to 24 h drives brain-wide upscaling in glutamatergic, but not other, synapses. Finally, overnight male-male social pairings induce increased BRP in excitatory synapses despite male-female pairings eliciting more waking activity, suggesting experience-specific plasticity. Within neurotransmitter class and waking context, BRP changes are similar across the 37 neuropil domains, indicating that similar synaptic scaling rules may apply across the brain during acute sleep loss and that sleep need may broadly alter excitatory-inhibitory balance in the central brain.
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Affiliation(s)
- Jacqueline T. Weiss
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, CA90095
- Neuroscience Interdepartmental Program, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Mei Z. Blundell
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, CA90095
| | - Prabhjit Singh
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, CA90095
| | - Jeffrey M. Donlea
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, CA90095
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7
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Eiman MN, Kumar S, Serrano Negron YL, Tansey TR, Harbison ST. Genome-wide association in Drosophila identifies a role for Piezo and Proc-R in sleep latency. Sci Rep 2024; 14:260. [PMID: 38168575 PMCID: PMC10761942 DOI: 10.1038/s41598-023-50552-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 12/21/2023] [Indexed: 01/05/2024] Open
Abstract
Sleep latency, the amount of time that it takes an individual to fall asleep, is a key indicator of sleep need. Sleep latency varies considerably both among and within species and is heritable, but lacks a comprehensive description of its underlying genetic network. Here we conduct a genome-wide association study of sleep latency. Using previously collected sleep and activity data on a wild-derived population of flies, we calculate sleep latency, confirming significant, heritable genetic variation for this complex trait. We identify 520 polymorphisms in 248 genes contributing to variability in sleep latency. Tests of mutations in 23 candidate genes and additional putative pan-neuronal knockdown of 9 of them implicated CG44153, Piezo, Proc-R and Rbp6 in sleep latency. Two large-effect mutations in the genes Proc-R and Piezo were further confirmed via genetic rescue. This work greatly enhances our understanding of the genetic factors that influence variation in sleep latency.
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Affiliation(s)
- Matthew N Eiman
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
- Drexel University College of Medicine, Philadelphia, PA, USA
| | - Shailesh Kumar
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
- Division of Neuroscience and Behavior, National Institute On Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Yazmin L Serrano Negron
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Terry R Tansey
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Susan T Harbison
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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8
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McMullen E, Hertenstein H, Strassburger K, Deharde L, Brankatschk M, Schirmeier S. Glycolytically impaired Drosophila glial cells fuel neural metabolism via β-oxidation. Nat Commun 2023; 14:2996. [PMID: 37225684 DOI: 10.1038/s41467-023-38813-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 05/17/2023] [Indexed: 05/26/2023] Open
Abstract
Neuronal function is highly energy demanding and thus requires efficient and constant metabolite delivery by glia. Drosophila glia are highly glycolytic and provide lactate to fuel neuronal metabolism. Flies are able to survive for several weeks in the absence of glial glycolysis. Here, we study how Drosophila glial cells maintain sufficient nutrient supply to neurons under conditions of impaired glycolysis. We show that glycolytically impaired glia rely on mitochondrial fatty acid breakdown and ketone body production to nourish neurons, suggesting that ketone bodies serve as an alternate neuronal fuel to prevent neurodegeneration. We show that in times of long-term starvation, glial degradation of absorbed fatty acids is essential to ensure survival of the fly. Further, we show that Drosophila glial cells act as a metabolic sensor and can induce mobilization of peripheral lipid stores to preserve brain metabolic homeostasis. Our study gives evidence of the importance of glial fatty acid degradation for brain function, and survival, under adverse conditions in Drosophila.
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Affiliation(s)
- Ellen McMullen
- Department of Molecular Biology and Genetics, University of South Bohemia, České Budějovice, Czech Republic
| | - Helen Hertenstein
- Zoology and Animal Physiology, Faculty of Biology, Technische Universität Dresden, Dresden, Germany
| | - Katrin Strassburger
- Zoology and Animal Physiology, Faculty of Biology, Technische Universität Dresden, Dresden, Germany
| | - Leon Deharde
- Zoology and Animal Physiology, Faculty of Biology, Technische Universität Dresden, Dresden, Germany
| | - Marko Brankatschk
- Biotechnologisches Zentrum, Technische Universität Dresden, Dresden, Germany.
| | - Stefanie Schirmeier
- Zoology and Animal Physiology, Faculty of Biology, Technische Universität Dresden, Dresden, Germany.
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9
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Dutta SB, Linneweber GA, Andriatsilavo M, Hiesinger PR, Hassan BA. EGFR-dependent suppression of synaptic autophagy is required for neuronal circuit development. Curr Biol 2023; 33:517-532.e5. [PMID: 36640763 DOI: 10.1016/j.cub.2022.12.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 10/31/2022] [Accepted: 12/14/2022] [Indexed: 01/15/2023]
Abstract
The development of neuronal connectivity requires stabilization of dynamic axonal branches at sites of synapse formation. Models that explain how axonal branching is coupled to synaptogenesis postulate molecular regulators acting in a spatiotemporally restricted fashion to ensure branching toward future synaptic partners while also stabilizing the emerging synaptic contacts between such partners. We investigated this question using neuronal circuit development in the Drosophila brain as a model system. We report that epidermal growth factor receptor (EGFR) activity is required in presynaptic axonal branches during two distinct temporal intervals to regulate circuit wiring in the developing Drosophila visual system. EGFR is required early to regulate primary axonal branching. EGFR activity is then independently required at a later stage to prevent degradation of the synaptic active zone protein Bruchpilot (Brp). Inactivation of EGFR results in a local increase of autophagy in presynaptic branches and the translocation of active zone proteins into autophagic vesicles. The protection of synaptic material during this later interval of wiring ensures the stabilization of terminal branches, circuit connectivity, and appropriate visual behavior. Phenotypes of EGFR inactivation can be rescued by increasing Brp levels or downregulating autophagy. In summary, we identify a temporally restricted molecular mechanism required for coupling axonal branching and synaptic stabilization that contributes to the emergence of neuronal wiring specificity.
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Affiliation(s)
- Suchetana B Dutta
- Institut du Cerveau-Paris Brain Institute (ICM), Sorbonne Université, Inserm, CNRS, Hôpital Pitié Salpêtrière, 75013 Paris, France; Division of Neurobiology, Free University of Berlin, 14195 Berlin, Germany; Einstein-BIH, Charité Universitätsmedizin, 10117 Berlin, Germany
| | | | - Maheva Andriatsilavo
- Institut du Cerveau-Paris Brain Institute (ICM), Sorbonne Université, Inserm, CNRS, Hôpital Pitié Salpêtrière, 75013 Paris, France; Division of Neurobiology, Free University of Berlin, 14195 Berlin, Germany; Einstein-BIH, Charité Universitätsmedizin, 10117 Berlin, Germany
| | | | - Bassem A Hassan
- Institut du Cerveau-Paris Brain Institute (ICM), Sorbonne Université, Inserm, CNRS, Hôpital Pitié Salpêtrière, 75013 Paris, France; Division of Neurobiology, Free University of Berlin, 14195 Berlin, Germany; Einstein-BIH, Charité Universitätsmedizin, 10117 Berlin, Germany.
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10
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Zhang W, Geng X, Dong Q, Li X, Ye P, Lin M, Xu B, Jiang H. Crosstalk between autophagy and the Keap1-Nrf2-ARE pathway regulates realgar-induced neurotoxicity. JOURNAL OF ETHNOPHARMACOLOGY 2023; 301:115776. [PMID: 36191662 DOI: 10.1016/j.jep.2022.115776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/22/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Realgar, the main component of which is As2S2 or As4S4 (≥90%), is a traditional Chinese natural medicine that has been used to treat carbuncles, furuncles, snake and insect bites, abdominal pain caused by parasitic worms, and epilepsy in China for many years. Because realgar contains arsenic, chronic or excessive use of single-flavor realgar and realgar-containing Chinese patent medicine can lead to drug-induced arsenic poisoning, but the exact mechanism underlying its toxicity to the central nervous system is unclear. AIM OF THE STUDY The aim of this study was to clarify the mechanism of realgar-induced neurotoxicity and to investigate the effects of realgar on autophagy and the Keap1-Nrf2-ARE pathway. MATERIALS AND METHODS We used rats treated with the autophagy inhibitor 3-methyladenine (3-MA) or adeno-associated virus (AAV2/9-r-shRNA-Sqstm1, sh-p62) to investigate realgar-induced neurotoxicity and explore the specific relationship between autophagy and the Keap1-Nrf2-ARE pathway (the Nrf2 pathway) in the cerebral cortex. Molecular docking analysis was used to assess the interactions among the Nrf2, p62 and Keap1 proteins. RESULTS Our results showed that arsenic from realgar accumulated in the brain and blood to cause neuronal and synaptic damage, decrease exploratory behavior and spontaneous movement, and impair memory ability in rats. The mechanism may have involved realgar-mediated autophagy impairment and continuous activation of the Nrf2 pathway via the LC3-p62-Keap1-Nrf2 axis. However, because this activation of the Nrf2 pathway was not sufficient to counteract oxidative damage, apoptosis was aggravated in the cerebral cortex. CONCLUSIONS This study revealed that autophagy, the Nrf2 pathway, and apoptosis are involved in realgar-induced central nervous system toxicity and identified p62 as the hub of the LC3-p62-Keap1-Nrf2 axis in the regulation of autophagy, the Nrf2 pathway, and apoptosis.
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Affiliation(s)
- Weiwei Zhang
- School of Public Health, China Medical University, Shenyang, Liaoning, 110122, PR China; The Key Laboratory of Liaoning Province on Toxic and Biological Effects of Arsenic, Liaoning, PR China.
| | - Xu Geng
- School of Public Health, China Medical University, Shenyang, Liaoning, 110122, PR China.
| | - Qing Dong
- School of Public Health, China Medical University, Shenyang, Liaoning, 110122, PR China.
| | - Xiuhan Li
- School of Public Health, China Medical University, Shenyang, Liaoning, 110122, PR China.
| | - Ping Ye
- School of Public Health, China Medical University, Shenyang, Liaoning, 110122, PR China.
| | - Mengyuan Lin
- School of Public Health, China Medical University, Shenyang, Liaoning, 110122, PR China.
| | - Bin Xu
- School of Public Health, China Medical University, Shenyang, Liaoning, 110122, PR China.
| | - Hong Jiang
- School of Public Health, China Medical University, Shenyang, Liaoning, 110122, PR China; The Key Laboratory of Liaoning Province on Toxic and Biological Effects of Arsenic, Liaoning, PR China.
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11
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Symonenko AV, Roshina NV, Krementsova AV, Rybina OY, Pasyukova EG. Shuttle craft Gene Affects Lifespan of Drosophila melanogaster by Controlling Early Development and Modifying Aging Program. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:1611-1621. [PMID: 36717450 DOI: 10.1134/s0006297922120161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Fundamental mechanisms underlying genetic control of lifespan are intensively studied and discussed due to the increasing importance of extending healthy human life. The stc gene of the model organism Drosophila melanogaster encodes a transcription factor, homolog of the human transcription factor NF-X1, involved in regulation of neuronal development and other processes, as well as in control of lifespan. In this work, we demonstrate that the stc knockdown in embryonic and nerve cells leads to changes in lifespan, with the nature of changes depending on the cell type and sex of individuals. Based on our results, we suggest that stc gene is involved in transcription regulation throughout life, and, as a result, also affects a complex integral trait, lifespan. At the same time, we show that the reduction of stc expression in neurons can alleviate the negative effect of glutamate on longevity, possibly preventing development of glutamate excitotoxicity, thus modifying the cell death program and preventing death of individuals due to phenoptosis.
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Affiliation(s)
- Alexander V Symonenko
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Natalia V Roshina
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Moscow, 123182, Russia.,Vavilov Institute of General Genetics, Russian Academy of Sciences, 11999 Moscow, Russia
| | - Anna V Krementsova
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Moscow, 123182, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Olga Y Rybina
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Moscow, 123182, Russia.,Moscow Pedagogical State University, Moscow, 119991, Russia
| | - Elena G Pasyukova
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
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12
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Turrel O, Ramesh N, Escher MJF, Pooryasin A, Sigrist SJ. Transient active zone remodeling in the Drosophila mushroom body supports memory. Curr Biol 2022; 32:4900-4913.e4. [PMID: 36327980 DOI: 10.1016/j.cub.2022.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 08/15/2022] [Accepted: 10/06/2022] [Indexed: 11/22/2022]
Abstract
Elucidating how the distinct components of synaptic plasticity dynamically orchestrate the distinct stages of memory acquisition and maintenance within neuronal networks remains a major challenge. Specifically, plasticity processes tuning the functional and also structural state of presynaptic active zone (AZ) release sites are widely observed in vertebrates and invertebrates, but their behavioral relevance remains mostly unclear. We here provide evidence that a transient upregulation of presynaptic AZ release site proteins supports aversive olfactory mid-term memory in the Drosophila mushroom body (MB). Upon paired aversive olfactory conditioning, AZ protein levels (ELKS-family BRP/(m)unc13-family release factor Unc13A) increased for a few hours with MB-lobe-specific dynamics. Kenyon cell (KC, intrinsic MB neurons)-specific knockdown (KD) of BRP did not affect aversive olfactory short-term memory (STM) but strongly suppressed aversive mid-term memory (MTM). Different proteins crucial for the transport of AZ biosynthetic precursors (transport adaptor Aplip1/Jip-1; kinesin motor IMAC/Unc104; small GTPase Arl8) were also specifically required for the formation of aversive olfactory MTM. Consistent with the merely transitory increase of AZ proteins, BRP KD did not interfere with the formation of aversive olfactory long-term memory (LTM; i.e., 1 day). Our data suggest that the remodeling of presynaptic AZ refines the MB circuitry after paired aversive conditioning, over a time window of a few hours, to display aversive olfactory memories.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Niraja Ramesh
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Marc J F Escher
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Atefeh Pooryasin
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
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13
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Ho MCW, Tabuchi M, Xie X, Brown MP, Luu S, Wang S, Kolodkin AL, Liu S, Wu MN. Sleep need-dependent changes in functional connectivity facilitate transmission of homeostatic sleep drive. Curr Biol 2022; 32:4957-4966.e5. [PMID: 36240772 PMCID: PMC9691613 DOI: 10.1016/j.cub.2022.09.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/28/2022] [Accepted: 09/23/2022] [Indexed: 11/05/2022]
Abstract
How the homeostatic drive for sleep accumulates over time and is released remains poorly understood. In Drosophila, we previously identified the R5 ellipsoid body (EB) neurons as putative sleep drive neurons1 and recently described a mechanism by which astrocytes signal to these cells to convey sleep need.2 Here, we examine the mechanisms acting downstream of the R5 neurons to promote sleep. EM connectome data demonstrate that R5 neurons project to EPG neurons.3 Broad thermogenetic activation of EPG neurons promotes sleep, whereas inhibiting these cells reduces homeostatic sleep rebound. Perforated patch-clamp recordings reveal that EPG neurons exhibit elevated spontaneous firing following sleep deprivation, which likely depends on an increase in extrinsic excitatory inputs. Our data suggest that cholinergic R5 neurons participate in the homeostatic regulation of sleep, and epistasis experiments indicate that the R5 neurons act upstream of EPG neurons to promote sleep. Finally, we show that the physical and functional connectivity between the R5 and EPG neurons increases with greater sleep need. Importantly, dual patch-clamp recordings demonstrate that activating R5 neurons induces cholinergic-dependent excitatory postsynaptic responses in EPG neurons. Moreover, sleep loss triggers an increase in the amplitude of these responses, as well as in the proportion of EPG neurons that respond. Together, our data support a model whereby sleep drive strengthens the functional connectivity between R5 and EPG neurons, triggering sleep when a sufficient number of EPG neurons are activated. This process could enable the proper timing of the accumulation and release of sleep drive.
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Affiliation(s)
- Margaret C W Ho
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Masashi Tabuchi
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xiaojun Xie
- The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China
| | - Matthew P Brown
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Skylar Luu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Serena Wang
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Alex L Kolodkin
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Sha Liu
- VIB Center for Brain & Disease Research and Department of Neurosciences, KU Leuven, Leuven 3000, Belgium
| | - Mark N Wu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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14
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Andreani T, Rosensweig C, Sisobhan S, Ogunlana E, Kath W, Allada R. Circadian programming of the ellipsoid body sleep homeostat in Drosophila. eLife 2022; 11:e74327. [PMID: 35735904 PMCID: PMC9270026 DOI: 10.7554/elife.74327] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 06/23/2022] [Indexed: 11/18/2022] Open
Abstract
Homeostatic and circadian processes collaborate to appropriately time and consolidate sleep and wake. To understand how these processes are integrated, we scheduled brief sleep deprivation at different times of day in Drosophila and find elevated morning rebound compared to evening. These effects depend on discrete morning and evening clock neurons, independent of their roles in circadian locomotor activity. In the R5 ellipsoid body sleep homeostat, we identified elevated morning expression of activity dependent and presynaptic gene expression as well as the presynaptic protein BRUCHPILOT consistent with regulation by clock circuits. These neurons also display elevated calcium levels in response to sleep loss in the morning, but not the evening consistent with the observed time-dependent sleep rebound. These studies reveal the circuit and molecular mechanisms by which discrete circadian clock neurons program a homeostatic sleep center.
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Affiliation(s)
- Tomas Andreani
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
| | - Clark Rosensweig
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
| | - Shiju Sisobhan
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
| | - Emmanuel Ogunlana
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
| | - William Kath
- Department of Engineering Sciences and Applied Mathematics, Northwestern UniversityEvanstonUnited States
| | - Ravi Allada
- Department of Neurobiology, Northwestern UniversityChicagoUnited States
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15
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Duhart JC, Mosca TJ. Genetic regulation of central synapse formation and organization in Drosophila melanogaster. Genetics 2022; 221:6597078. [PMID: 35652253 DOI: 10.1093/genetics/iyac078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/29/2022] [Indexed: 01/04/2023] Open
Abstract
A goal of modern neuroscience involves understanding how connections in the brain form and function. Such a knowledge is essential to inform how defects in the exquisite complexity of nervous system growth influence neurological disease. Studies of the nervous system in the fruit fly Drosophila melanogaster enabled the discovery of a wealth of molecular and genetic mechanisms underlying development of synapses-the specialized cell-to-cell connections that comprise the essential substrate for information flow and processing in the nervous system. For years, the major driver of knowledge was the neuromuscular junction due to its ease of examination. Analogous studies in the central nervous system lagged due to a lack of genetic accessibility of specific neuron classes, synaptic labels compatible with cell-type-specific access, and high resolution, quantitative imaging strategies. However, understanding how central synapses form remains a prerequisite to understanding brain development. In the last decade, a host of new tools and techniques extended genetic studies of synapse organization into central circuits to enhance our understanding of synapse formation, organization, and maturation. In this review, we consider the current state-of-the-field. We first discuss the tools, technologies, and strategies developed to visualize and quantify synapses in vivo in genetically identifiable neurons of the Drosophila central nervous system. Second, we explore how these tools enabled a clearer understanding of synaptic development and organization in the fly brain and the underlying molecular mechanisms of synapse formation. These studies establish the fly as a powerful in vivo genetic model that offers novel insights into neural development.
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Affiliation(s)
- Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Timothy J Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
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16
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Ukita Y, Okumura M, Chihara T. Ubiquitin proteasome system in circadian rhythm and sleep homeostasis: Lessons from Drosophila. Genes Cells 2022; 27:381-391. [PMID: 35438236 PMCID: PMC9322287 DOI: 10.1111/gtc.12935] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 11/30/2022]
Abstract
Sleep is regulated by two main processes: the circadian clock and sleep homeostasis. Circadian rhythms have been well studied at the molecular level. In the Drosophila circadian clock neurons, the core clock proteins are precisely regulated by post-translational modifications and degraded via the ubiquitin-proteasome system (UPS). Sleep homeostasis, however, is less understood; nevertheless, recent reports suggest that proteasome-mediated degradation of core clock proteins or synaptic proteins contributes to the regulation of sleep amount. Here, we review the molecular mechanism of the UPS and summarize the role of protein degradation in the regulation of circadian clock and homeostatic sleep in Drosophila. Moreover, we discuss the potential interaction between circadian clock and homeostatic sleep regulation with a prime focus on E3 ubiquitin ligases.
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Affiliation(s)
- Yumiko Ukita
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Misako Okumura
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan.,Program of Basic Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Takahiro Chihara
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan.,Program of Basic Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
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17
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Weiss JT, Donlea JM. Roles for Sleep in Neural and Behavioral Plasticity: Reviewing Variation in the Consequences of Sleep Loss. Front Behav Neurosci 2022; 15:777799. [PMID: 35126067 PMCID: PMC8810646 DOI: 10.3389/fnbeh.2021.777799] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/16/2021] [Indexed: 12/13/2022] Open
Abstract
Sleep is a vital physiological state that has been broadly conserved across the evolution of animal species. While the precise functions of sleep remain poorly understood, a large body of research has examined the negative consequences of sleep loss on neural and behavioral plasticity. While sleep disruption generally results in degraded neural plasticity and cognitive function, the impact of sleep loss can vary widely with age, between individuals, and across physiological contexts. Additionally, several recent studies indicate that sleep loss differentially impacts distinct neuronal populations within memory-encoding circuitry. These findings indicate that the negative consequences of sleep loss are not universally shared, and that identifying conditions that influence the resilience of an organism (or neuron type) to sleep loss might open future opportunities to examine sleep's core functions in the brain. Here, we discuss the functional roles for sleep in adaptive plasticity and review factors that can contribute to individual variations in sleep behavior and responses to sleep loss.
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Affiliation(s)
- Jacqueline T. Weiss
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, United States
| | - Jeffrey M. Donlea
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
- *Correspondence: Jeffrey M. Donlea
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18
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Piao C, Sigrist SJ. (M)Unc13s in Active Zone Diversity: A Drosophila Perspective. Front Synaptic Neurosci 2022; 13:798204. [PMID: 35046788 PMCID: PMC8762327 DOI: 10.3389/fnsyn.2021.798204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/29/2021] [Indexed: 12/03/2022] Open
Abstract
The so-called active zones at pre-synaptic terminals are the ultimate filtering devices, which couple between action potential frequency and shape, and the information transferred to the post-synaptic neurons, finally tuning behaviors. Within active zones, the release of the synaptic vesicle operates from specialized “release sites.” The (M)Unc13 class of proteins is meant to define release sites topologically and biochemically, and diversity between Unc13-type release factor isoforms is suspected to steer diversity at active zones. The two major Unc13-type isoforms, namely, Unc13A and Unc13B, have recently been described from the molecular to the behavioral level, exploiting Drosophila being uniquely suited to causally link between these levels. The exact nanoscale distribution of voltage-gated Ca2+ channels relative to release sites (“coupling”) at pre-synaptic active zones fundamentally steers the release of the synaptic vesicle. Unc13A and B were found to be either tightly or loosely coupled across Drosophila synapses. In this review, we reported recent findings on diverse aspects of Drosophila Unc13A and B, importantly, their nano-topological distribution at active zones and their roles in release site generation, active zone assembly, and pre-synaptic homeostatic plasticity. We compared their stoichiometric composition at different synapse types, reviewing the correlation between nanoscale distribution of these two isoforms and release physiology and, finally, discuss how isoform-specific release components might drive the functional heterogeneity of synapses and encode discrete behavior.
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Affiliation(s)
- Chengji Piao
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Stephan J. Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
- *Correspondence: Stephan J. Sigrist
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19
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Reyes-Resina I, Samer S, Kreutz MR, Oelschlegel AM. Molecular Mechanisms of Memory Consolidation That Operate During Sleep. Front Mol Neurosci 2021; 14:767384. [PMID: 34867190 PMCID: PMC8636908 DOI: 10.3389/fnmol.2021.767384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
The role of sleep for brain function has been in the focus of interest for many years. It is now firmly established that sleep and the corresponding brain activity is of central importance for memory consolidation. Less clear are the underlying molecular mechanisms and their specific contribution to the formation of long-term memory. In this review, we summarize the current knowledge of such mechanisms and we discuss the several unknowns that hinder a deeper appreciation of how molecular mechanisms of memory consolidation during sleep impact synaptic function and engram formation.
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Affiliation(s)
- Irene Reyes-Resina
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Sebastian Samer
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Center for Behavioral Brain Sciences, Otto von Guericke University, Magdeburg, Germany.,German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Anja M Oelschlegel
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
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20
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Weiss JT, Donlea JM. Sleep deprivation results in diverse patterns of synaptic scaling across the Drosophila mushroom bodies. Curr Biol 2021; 31:3248-3261.e3. [PMID: 34107302 PMCID: PMC8355077 DOI: 10.1016/j.cub.2021.05.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/22/2021] [Accepted: 05/11/2021] [Indexed: 11/19/2022]
Abstract
Sleep is essential for a variety of plastic processes, including learning and memory. However, the consequences of insufficient sleep on circuit connectivity remain poorly understood. To better appreciate the effects of sleep loss on synaptic connectivity across a memory-encoding circuit, we examined changes in the distribution of synaptic markers in the Drosophila mushroom body (MB). Protein-trap tags for active zone components indicate that recent sleep time is inversely correlated with Bruchpilot (BRP) abundance in the MB lobes; sleep loss elevates BRP while sleep induction reduces BRP across the MB. Overnight sleep deprivation also elevated levels of dSyd-1 and Cacophony, but not other pre-synaptic proteins. Cell-type-specific genetic reporters show that MB-intrinsic Kenyon cells (KCs) exhibit increased pre-synaptic BRP throughout the axonal lobes after sleep deprivation; similar increases were not detected in projections from large interneurons or dopaminergic neurons that innervate the MB. These results indicate that pre-synaptic plasticity in KCs is responsible for elevated levels of BRP in the MB lobes of sleep-deprived flies. Because KCs provide synaptic inputs to several classes of post-synaptic partners, we next used a fluorescent reporter for synaptic contacts to test whether each class of KC output connections is scaled uniformly by sleep loss. The KC output synapses that we observed here can be divided into three classes: KCs to MB interneurons; KCs to dopaminergic neurons; and KCs to MB output neurons. No single class showed uniform scaling across each constituent member, indicating that different rules may govern plasticity during sleep loss across cell types.
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Affiliation(s)
- Jacqueline T Weiss
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA; Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jeffrey M Donlea
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA.
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21
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Huang S, Sigrist SJ. Presynaptic and postsynaptic long-term plasticity in sleep homeostasis. Curr Opin Neurobiol 2021; 69:1-10. [DOI: 10.1016/j.conb.2020.11.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/03/2020] [Accepted: 11/15/2020] [Indexed: 12/25/2022]
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22
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Li G, Hidalgo A. The Toll Route to Structural Brain Plasticity. Front Physiol 2021; 12:679766. [PMID: 34290618 PMCID: PMC8287419 DOI: 10.3389/fphys.2021.679766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/02/2021] [Indexed: 11/13/2022] Open
Abstract
The human brain can change throughout life as we learn, adapt and age. A balance between structural brain plasticity and homeostasis characterizes the healthy brain, and the breakdown of this balance accompanies brain tumors, psychiatric disorders, and neurodegenerative diseases. However, the link between circuit modifications, brain function, and behavior remains unclear. Importantly, the underlying molecular mechanisms are starting to be uncovered. The fruit-fly Drosophila is a very powerful model organism to discover molecular mechanisms and test them in vivo. There is abundant evidence that the Drosophila brain is plastic, and here we travel from the pioneering discoveries to recent findings and progress on molecular mechanisms. We pause on the recent discovery that, in the Drosophila central nervous system, Toll receptors—which bind neurotrophin ligands—regulate structural plasticity during development and in the adult brain. Through their topographic distribution across distinct brain modules and their ability to switch between alternative signaling outcomes, Tolls can enable the brain to translate experience into structural change. Intriguing similarities between Toll and mammalian Toll-like receptor function could reveal a further involvement in structural plasticity, degeneration, and disease in the human brain.
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Affiliation(s)
- Guiyi Li
- Plasticity and Regeneration Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Alicia Hidalgo
- Plasticity and Regeneration Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
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23
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Flores-Valle A, Gonçalves PJ, Seelig JD. Integration of sleep homeostasis and navigation in Drosophila. PLoS Comput Biol 2021; 17:e1009088. [PMID: 34252086 PMCID: PMC8297946 DOI: 10.1371/journal.pcbi.1009088] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 07/22/2021] [Accepted: 05/17/2021] [Indexed: 11/25/2022] Open
Abstract
During sleep, the brain undergoes dynamic and structural changes. In Drosophila, such changes have been observed in the central complex, a brain area important for sleep control and navigation. The connectivity of the central complex raises the question about how navigation, and specifically the head direction system, can operate in the face of sleep related plasticity. To address this question, we develop a model that integrates sleep homeostasis and head direction. We show that by introducing plasticity, the head direction system can function in a stable way by balancing plasticity in connected circuits that encode sleep pressure. With increasing sleep pressure, the head direction system nevertheless becomes unstable and a sleep phase with a different plasticity mechanism is introduced to reset network connectivity. The proposed integration of sleep homeostasis and head direction circuits captures features of their neural dynamics observed in flies and mice.
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Affiliation(s)
- Andres Flores-Valle
- Center of Advanced European Studies and Research (caesar), Bonn, Germany
- International Max Planck Research School for Brain and Behavior, Bonn, Germany
| | - Pedro J. Gonçalves
- Max Planck Research Group Neural Systems Analysis, Center of Advanced European Studies and Research (caesar), Bonn, Germany
- Computational Neuroengineering, Department of Electrical and Computer Engineering, Technical University of Munich, Munich, Germany
| | - Johannes D. Seelig
- Center of Advanced European Studies and Research (caesar), Bonn, Germany
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24
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McDonald NA, Shen K. Finding functions of phase separation in the presynapse. Curr Opin Neurobiol 2021; 69:178-184. [PMID: 33979706 DOI: 10.1016/j.conb.2021.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/01/2021] [Accepted: 04/05/2021] [Indexed: 12/23/2022]
Abstract
Synapses are the basic units of neuronal communication. Understanding how synapses assemble and function is therefore essential to understanding nervous systems. Decades of study have identified many molecular components and functional mechanisms of synapses. Recently, an additional level of synaptic protein organization has been identified: phase separation. In the presynapse, components of the central active zone and a synaptic vesicle-clustering factor have been shown to form liquid-liquid phase-separated condensates or hydrogels. New in vivo functional studies have directly tested how phase separation impacts both synapse formation and function. Here, we review this emerging evidence for in vivo functional roles of phase separation at the presynapse and discuss future functional studies necessary to understand its complexity.
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Affiliation(s)
| | - Kang Shen
- Department of Biology, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
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25
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Soykan T, Haucke V, Kuijpers M. Mechanism of synaptic protein turnover and its regulation by neuronal activity. Curr Opin Neurobiol 2021; 69:76-83. [PMID: 33744822 DOI: 10.1016/j.conb.2021.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 12/23/2022]
Abstract
Neurons are long-lived cells with a complex architecture, in which synapses may be located far away from the cell body and are subject to plastic changes, thereby posing special challenges to the systems that maintain and dynamically regulate the synaptic proteome. These mechanisms include neuronal autophagy and the endolysosome pathway, as well as the ubiquitin/proteasome system, which cooperate in the constitutive and regulated turnover of presynaptic and postsynaptic proteins. Here, we summarize the pathways involved in synaptic protein degradation and the mechanisms underlying their regulation, for example, by neuronal activity, with an emphasis on the presynaptic compartment and outline perspectives for future research. Keywords: Synapse, Synaptic vesicle, Autophagy, Endolysosome, Proteasome, Protein turnover, Protein degradation, Endosome, Lysosome.
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Affiliation(s)
- Tolga Soykan
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany; Freie Universität Berlin, Faculty of Biology, Chemistry, Pharmacy, 14195, Berlin, Germany.
| | - Marijn Kuijpers
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany.
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26
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Ramesh N, Escher MJF, Mampell MM, Böhme MA, Götz TWB, Goel P, Matkovic T, Petzoldt AG, Dickman D, Sigrist SJ. Antagonistic interactions between two Neuroligins coordinate pre- and postsynaptic assembly. Curr Biol 2021; 31:1711-1725.e5. [PMID: 33651992 DOI: 10.1016/j.cub.2021.01.093] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 11/18/2020] [Accepted: 01/26/2021] [Indexed: 12/17/2022]
Abstract
As a result of developmental synapse formation, the presynaptic neurotransmitter release machinery becomes accurately matched with postsynaptic neurotransmitter receptors. Trans-synaptic signaling is executed through cell adhesion proteins such as Neurexin::Neuroligin pairs but also through diffusible and cytoplasmic signals. How exactly pre-post coordination is ensured in vivo remains largely enigmatic. Here, we identified a "molecular choreography" coordinating pre- with postsynaptic assembly during the developmental formation of Drosophila neuromuscular synapses. Two presynaptic Neurexin-binding scaffold proteins, Syd-1 and Spinophilin (Spn), spatio-temporally coordinated pre-post assembly in conjunction with two postsynaptically operating, antagonistic Neuroligin species: Nlg1 and Nlg2. The Spn/Nlg2 module promoted active zone (AZ) maturation by driving the accumulation of AZ scaffold proteins critical for synaptic vesicle release. Simultaneously, these regulators restricted postsynaptic glutamate receptor incorporation. Both functions of the Spn/Nlg2 module were directly antagonized by Syd-1/Nlg1. Nlg1 and Nlg2 also had divergent effects on Nrx-1 in vivo motility. Concerning diffusible signals, Spn and Syd-1 antagonistically controlled the levels of Munc13-family protein Unc13B at nascent AZs, whose release function facilitated glutamate receptor incorporation at assembling postsynaptic specializations. As a result, we here provide direct in vivo evidence illustrating how a highly regulative and interleaved communication between cell adhesion protein signaling complexes and diffusible signals allows for a precise coordination of pre- with postsynaptic assembly. It will be interesting to analyze whether this logic also transfers to plasticity processes.
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Affiliation(s)
- Niraja Ramesh
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Marc J F Escher
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Malou M Mampell
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Mathias A Böhme
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany; Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Torsten W B Götz
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Pragya Goel
- Department of Neurobiology, University of Southern California, Los Angeles, CA, USA
| | - Tanja Matkovic
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Astrid G Petzoldt
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA, USA
| | - Stephan J Sigrist
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
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Melnattur K, Morgan E, Duong V, Kalra A, Shaw PJ. The Sleep Nullifying Apparatus: A Highly Efficient Method of Sleep Depriving Drosophila. J Vis Exp 2020. [PMID: 33369606 DOI: 10.3791/62105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Sleep homeostasis, the increase in sleep observed following sleep loss, is one of the defining criteria used to identify sleep throughout the animal kingdom. As a consequence, sleep deprivation and sleep restriction are powerful tools that are commonly used to provide insight into sleep function. Nonetheless, sleep deprivation experiments are inherently problematic in that the deprivation stimulus itself may be the cause of observed changes in physiology and behavior. Accordingly, successful sleep deprivation techniques should keep animals awake and, ideally, result in a robust sleep rebound without also inducing a large number of unintended consequences. Here, we describe a sleep deprivation technique for Drosophila melanogaster. The Sleep Nullifying Apparatus (SNAP) administers a stimulus every 10s to induce negative geotaxis. Although the stimulus is predictable, the SNAP effectively prevents >95% of nighttime sleep even in flies with high sleep drive. Importantly, the subsequent homeostatic response is very similar to that achieved using hand-deprivation. The timing and spacing of the stimuli can be modified to minimize sleep loss and thus examine non-specific effects of the stimulus on physiology and behavior. The SNAP can also be used for sleep restriction and to assess arousal thresholds. The SNAP is a powerful sleep disruption technique that can be used to better understand sleep function.
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Affiliation(s)
- Krishna Melnattur
- Department of Neuroscience, Washington University School of Medicine
| | - Ellen Morgan
- Department of Neuroscience, Washington University School of Medicine
| | - Vincent Duong
- Department of Neuroscience, Washington University School of Medicine
| | - Arjan Kalra
- Department of Neuroscience, Washington University School of Medicine
| | - Paul J Shaw
- Department of Neuroscience, Washington University School of Medicine;
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Insulin and Leptin/Upd2 Exert Opposing Influences on Synapse Number in Fat-Sensing Neurons. Cell Metab 2020; 32:786-800.e7. [PMID: 32976758 PMCID: PMC7642105 DOI: 10.1016/j.cmet.2020.08.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 06/29/2020] [Accepted: 08/28/2020] [Indexed: 01/20/2023]
Abstract
Energy-sensing neural circuits decide to expend or conserve resources based, in part, on the tonic, steady-state, energy-store information they receive. Tonic signals, in the form of adipose tissue-derived adipokines, set the baseline level of activity in the energy-sensing neurons, thereby providing context for interpretation of additional inputs. However, the mechanism by which tonic adipokine information establishes steady-state neuronal function has heretofore been unclear. We show here that under conditions of nutrient surplus, Upd2, a Drosophila leptin ortholog, regulates actin-based synapse reorganization to reduce bouton number in an inhibitory circuit, thus establishing a neural tone that is permissive for insulin release. Unexpectedly, we found that insulin feeds back on these same inhibitory neurons to conversely increase bouton number, resulting in maintenance of negative tone. Our results point to a mechanism by which two surplus-sensing hormonal systems, Upd2/leptin and insulin, converge on a neuronal circuit with opposing outcomes to establish energy-store-dependent neuron activity.
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