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Cheng H, Zhong D, Tan Y, Huang M, Xijie S, Pan H, Yang Z, Huang F, Li F, Tang Q. Advancements in research on the association between the biological CLOCK and type 2 diabetes. Front Endocrinol (Lausanne) 2024; 15:1320605. [PMID: 38872971 PMCID: PMC11169578 DOI: 10.3389/fendo.2024.1320605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 05/15/2024] [Indexed: 06/15/2024] Open
Abstract
Due to the Earth's rotation, the natural environment exhibits a light-dark diurnal cycle close to 24 hours. To adapt to this energy intake pattern, organisms have developed a 24-hour rhythmic diurnal cycle over long periods, known as the circadian rhythm, or biological clock. With the gradual advancement of research on the biological clock, it has become increasingly evident that disruptions in the circadian rhythm are closely associated with the occurrence of type 2 diabetes (T2D). To further understand the progress of research on T2D and the biological clock, this paper reviews the correlation between the biological clock and glucose metabolism and analyzes its potential mechanisms. Based on this, we discuss the potential factors contributing to circadian rhythm disruption and their impact on the risk of developing T2D, aiming to explore new possible intervention measures for the prevention and treatment of T2D in the future. Under the light-dark circadian rhythm, in order to adapt to this change, the human body forms an internal biological clock involving a variety of genes, proteins and other molecules. The main mechanism is the transcription-translation feedback loop centered on the CLOCK/BMAL1 heterodimer. The expression of important circadian clock genes that constitute this loop can regulate T2DM-related blood glucose traits such as glucose uptake, fat metabolism, insulin secretion/glucagon secretion and sensitivity in various peripheral tissues and organs. In addition, sleep, light, and dietary factors under circadian rhythms also affect the occurrence of T2DM.
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Affiliation(s)
- Hui Cheng
- Nanhai Hospital of Traditional Chinese Medicine, Jinan University, Foshan, China
- Institute of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Dayuan Zhong
- Nanhai Hospital of Traditional Chinese Medicine, Jinan University, Foshan, China
| | - Yimei Tan
- Nanhai Hospital of Traditional Chinese Medicine, Jinan University, Foshan, China
- Graduate school, Guangzhou University of Chinese Medicine, Foshan, China
| | - Menghe Huang
- Nanhai Hospital of Traditional Chinese Medicine, Jinan University, Foshan, China
- Graduate school, Guangzhou University of Chinese Medicine, Foshan, China
| | - Sun Xijie
- Institute of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Hong Pan
- Nanhai Hospital of Traditional Chinese Medicine, Jinan University, Foshan, China
- Institute of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Zixian Yang
- Nanhai Hospital of Traditional Chinese Medicine, Jinan University, Foshan, China
- Institute of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Fangmei Huang
- Nanhai Hospital of Traditional Chinese Medicine, Jinan University, Foshan, China
- Institute of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Feifan Li
- Nanhai Hospital of Traditional Chinese Medicine, Jinan University, Foshan, China
- Institute of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Qizhi Tang
- Nanhai Hospital of Traditional Chinese Medicine, Jinan University, Foshan, China
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Levy K, Wegrzyn Y, Moaraf S, Barnea A, Ayali A. When night becomes day: Artificial light at night alters insect behavior under semi-natural conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 926:171905. [PMID: 38531451 DOI: 10.1016/j.scitotenv.2024.171905] [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: 01/05/2024] [Revised: 02/18/2024] [Accepted: 03/20/2024] [Indexed: 03/28/2024]
Abstract
Light is the most important Zeitgeber for temporal synchronization in nature. Artificial light at night (ALAN) disrupts the natural light-dark rhythmicity and thus negatively affects animal behavior. However, to date, ALAN research has been mostly conducted under laboratory conditions in this context. Here, we used the field cricket, Gryllus bimaculatus, to investigate the effect of ALAN on insect behavior under semi-natural conditions, i.e., under shaded natural lighting conditions, natural temperature and soundscape. Male crickets were placed individually in outdoor enclosures and exposed to ALAN conditions ranging from <0.01 to 1500 lx intensity. The crickets' stridulation behavior was recorded for 14 consecutive days and nights and their daily activity patterns were analysed. ALAN impaired the crickets' stridulation rhythm, evoking a change in the crickets' naturally synchronized daily activity period. This was manifested by a light-intensity-dependent increase in the proportion of insects demonstrating an intrinsic circadian rhythm (free-run behavior). This also resulted in a change in the population's median activity cycle period. These ALAN-induced effects occurred despite the crickets' exposure to almost natural conditions. Our findings provide further validity to our previous studies on ALAN conducted under lab conditions and establish the deleterious impacts of ALAN on animal behavioral patterns. TEASER: Artificial light at night alters cricket behavior and desynchronizes their stridulation even under near-natural conditions.
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Affiliation(s)
- Keren Levy
- School of Zoology, Tel Aviv University, Tel-Aviv 6997801, Israel
| | - Yoav Wegrzyn
- School of Zoology, Tel Aviv University, Tel-Aviv 6997801, Israel
| | - Stan Moaraf
- School of Zoology, Tel Aviv University, Tel-Aviv 6997801, Israel; Department of Natural Sciences, The Open University of Israel, Ra'anana 4353701, Israel
| | - Anat Barnea
- Department of Natural Sciences, The Open University of Israel, Ra'anana 4353701, Israel
| | - Amir Ayali
- School of Zoology, Tel Aviv University, Tel-Aviv 6997801, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel-Aviv 6997801, Israel.
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Woodard G, Rosado JA, Li H. The physiological role of TRP channels in sleep and circadian rhythm. J Cell Mol Med 2024; 28:e18274. [PMID: 38676362 PMCID: PMC11053353 DOI: 10.1111/jcmm.18274] [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: 04/30/2023] [Revised: 10/24/2023] [Accepted: 01/05/2024] [Indexed: 04/28/2024] Open
Abstract
TRP channels, are non-specific cationic channels that are involved in multiple physiological processes that include salivation, cellular secretions, memory extinction and consolidation, temperature, pain, store-operated calcium entry, thermosensation and functionality of the nervous system. Here we choose to look at the evidence that decisively shows how TRP channels modulate human neuron plasticity as it relates to the molecular neurobiology of sleep/circadian rhythm. There are numerous model organisms of sleep and circadian rhythm that are the results of the absence or genetic manipulation of the non-specific cationic TRP channels. Drosophila and mice that have had their TRP channels genetically ablated or manipulated show strong evidence of changes in sleep duration, sleep activity, circadian rhythm and response to temperature, noxious odours and pattern of activity during both sleep and wakefulness along with cardiovascular and respiratory function during sleep. Indeed the role of TRP channels in regulating sleep and circadian rhythm is very interesting considering the parallel roles of TRP channels in thermoregulation and thermal response with concomitant responses in growth and degradation of neurites, peripheral nerves and neuronal brain networks. TRP channels provide evidence of an ability to create, regulate and modify our sleep and circadian rhythm in a wide array of physiological and pathophysiological conditions. In the current review, we summarize previous results and novel recent advances in the understanding of calcium ion entry via TRP channels in different sleep and circadian rhythm conditions. We discuss the role of TRP channels in sleep and circadian disorders.
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Affiliation(s)
- Geoffrey Woodard
- Department of PsychiatryUniformed Services University of Health SciencesBethesdaMarylandUSA
| | - Juan A. Rosado
- Department of PhysiologyUniversity of ExtremaduraCaceresSpain
| | - He Li
- Department of PsychiatryUniformed Services University of Health SciencesBethesdaMarylandUSA
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Li H, Li Z, Yuan X, Tian Y, Ye W, Zeng P, Li XM, Guo F. Dynamic encoding of temperature in the central circadian circuit coordinates physiological activities. Nat Commun 2024; 15:2834. [PMID: 38565846 PMCID: PMC10987497 DOI: 10.1038/s41467-024-47278-5] [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: 06/27/2023] [Accepted: 03/26/2024] [Indexed: 04/04/2024] Open
Abstract
The circadian clock regulates animal physiological activities. How temperature reorganizes circadian-dependent physiological activities remains elusive. Here, using in-vivo two-photon imaging with the temperature control device, we investigated the response of the Drosophila central circadian circuit to temperature variation and identified that DN1as serves as the most sensitive temperature-sensing neurons. The circadian clock gate DN1a's diurnal temperature response. Trans-synaptic tracing, connectome analysis, and functional imaging data reveal that DN1as bidirectionally targets two circadian neuronal subsets: activity-related E cells and sleep-promoting DN3s. Specifically, behavioral data demonstrate that the DN1a-E cell circuit modulates the evening locomotion peak in response to cold temperature, while the DN1a-DN3 circuit controls the warm temperature-induced nocturnal sleep reduction. Our findings systematically and comprehensively illustrate how the central circadian circuit dynamically integrates temperature and light signals to effectively coordinate wakefulness and sleep at different times of the day, shedding light on the conserved neural mechanisms underlying temperature-regulated circadian physiology in animals.
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Affiliation(s)
- Hailiang Li
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
| | - Zhiyi Li
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
| | - Xin Yuan
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
| | - Yue Tian
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
| | - Wenjing Ye
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
| | - Pengyu Zeng
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
| | - Xiao-Ming Li
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
- Department of Neurobiology and Department of Psychiatry of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Fang Guo
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China.
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China.
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China.
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Panda K, Mittapally R, Reddy P, Yadlapalli S, Meyhofer E. Micro-kelvin temperature-stable system for biocalorimetry applications. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:034902. [PMID: 38446002 PMCID: PMC10919956 DOI: 10.1063/5.0188285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 02/10/2024] [Indexed: 03/07/2024]
Abstract
Achieving micro-kelvin (µK) temperature stability is critical for many calorimetric applications. For example, sub-nanowatt resolution biocalorimetry requires stabilization of the temperature of the calorimeter to µK levels. Here, we describe how µK temperature stability can be accomplished in a prototypical calorimetric system consisting of two nested shields and a suspended capillary tube, which is well suited for biocalorimetry applications. Specifically, we show that by employing nested shields with µTorr-levels of vacuum in the space between them as well as precise feedback control of the temperature of the shields (performed using high-resolution temperature sensors), the effect of ambient temperature fluctuations on the inner shield and the capillary tube can be attenuated by ∼100 dB. We also show that this attenuation is key to achieving temperature stabilities within ±1 and ±3 µK (amplitude of oscillations) for the inner shield and the capillary tube sensor, respectively, measured in a bandwidth of 1 mHz over a period of 10 h at room temperature (∼20.9 ± 0.2 °C). We expect that the methods described here will play a key role in advancing biocalorimetry.
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Affiliation(s)
- Kanishka Panda
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Rohith Mittapally
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Pramod Reddy
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Swathi Yadlapalli
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Edgar Meyhofer
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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Suo H, Guo D, Zhao P, Zhang X, Wang Y, Zheng W, Li P, Yin T, Guan L, Wang Z, Wang F. Ultrasensitive Colorimetric Luminescence Thermometry by Progressive Phase Transition. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305241. [PMID: 38084003 PMCID: PMC10870082 DOI: 10.1002/advs.202305241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 11/22/2023] [Indexed: 02/17/2024]
Abstract
Luminescent materials that display quick spectral responses to thermal stimuli have attracted pervasive attention in sensing technologies. Herein, a programmable luminescence color switching in lanthanide-doped LiYO2 under thermal stimuli, based on deliberate control of the monoclinic (β) to tetragonal (α) phase transition in the crystal lattice, is reported. Specifically, a lanthanide-doping (Ln3+ ) approach to fine-tune the phase-transition temperature in a wide range from 294 to 359 K is developed. Accordingly, an array of Ln3+ -doped LiYO2 crystals that exhibit progressive phase transition, and thus sequential color switching at gradually increasing temperatures, is constructed. The tunable optical response to thermal stimuli is harnessed for colorimetric temperature indication and quantitative detection, demonstrating superior sensitivity and temperature resolution (Sr = 26.1% K-1 , δT = 0.008 K). The advances in controlling the phase-transition behavior of luminescent materials also offer exciting opportunities for high-performance personalized health monitoring.
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Affiliation(s)
- Hao Suo
- National‐Local Joint Engineering Laboratory of New Energy Photoelectric DevicesHebei Key Laboratory of Optic‐electronic Information and MaterialsCollege of Physics Science & TechnologyHebei UniversityBaoding071002China
- Department of Materials Science and EngineeringCity University of Hong KongKowloonHong Kong SAR999077China
| | - Dongxu Guo
- National‐Local Joint Engineering Laboratory of New Energy Photoelectric DevicesHebei Key Laboratory of Optic‐electronic Information and MaterialsCollege of Physics Science & TechnologyHebei UniversityBaoding071002China
| | - Peihang Zhao
- National‐Local Joint Engineering Laboratory of New Energy Photoelectric DevicesHebei Key Laboratory of Optic‐electronic Information and MaterialsCollege of Physics Science & TechnologyHebei UniversityBaoding071002China
| | - Xin Zhang
- Department of Materials Science and EngineeringCity University of Hong KongKowloonHong Kong SAR999077China
| | - Yu Wang
- National‐Local Joint Engineering Laboratory of New Energy Photoelectric DevicesHebei Key Laboratory of Optic‐electronic Information and MaterialsCollege of Physics Science & TechnologyHebei UniversityBaoding071002China
| | - Weilin Zheng
- Department of Materials Science and EngineeringCity University of Hong KongKowloonHong Kong SAR999077China
| | - Panlai Li
- National‐Local Joint Engineering Laboratory of New Energy Photoelectric DevicesHebei Key Laboratory of Optic‐electronic Information and MaterialsCollege of Physics Science & TechnologyHebei UniversityBaoding071002China
| | - Tao Yin
- National‐Local Joint Engineering Laboratory of New Energy Photoelectric DevicesHebei Key Laboratory of Optic‐electronic Information and MaterialsCollege of Physics Science & TechnologyHebei UniversityBaoding071002China
| | - Li Guan
- National‐Local Joint Engineering Laboratory of New Energy Photoelectric DevicesHebei Key Laboratory of Optic‐electronic Information and MaterialsCollege of Physics Science & TechnologyHebei UniversityBaoding071002China
| | - Zhijun Wang
- National‐Local Joint Engineering Laboratory of New Energy Photoelectric DevicesHebei Key Laboratory of Optic‐electronic Information and MaterialsCollege of Physics Science & TechnologyHebei UniversityBaoding071002China
| | - Feng Wang
- Department of Materials Science and EngineeringCity University of Hong KongKowloonHong Kong SAR999077China
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Matre D, Sallinen M, Phillips AJK, Moen LV, Nilsen KB, Haugen F. Night work, season and alertness as occupational safety hazards in the Arctic: protocol for the Noralert observational crossover study among Norwegian process operators. BMJ Open 2023; 13:e075107. [PMID: 37793926 PMCID: PMC10551971 DOI: 10.1136/bmjopen-2023-075107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/11/2023] [Indexed: 10/06/2023] Open
Abstract
INTRODUCTION The objective of this study is to determine the effects of night work, Arctic seasonal factors and cold working environments on human functions relevant to safety. The study aims to quantify the contribution of (1) several consecutive night shifts, (2) seasonal variation on sleepiness, alertness and circadian rhythm and (3) whether a computational model of sleep, circadian rhythms and cognitive performance can accurately predict the observed sleepiness and alertness. METHODS AND ANALYSIS In an observational crossover study of outdoor and indoor workers (n=120) on a three-shift schedule from an industrial plant in Norway (70 °N), measurements will be conducted during the summer and winter. Sleep duration and quality will be measured daily by smartphone questionnaire, aided by actigraphy and heart rate measurements. Sleepiness and alertness will be assessed at regular intervals by the Karolinska Sleepiness Scale and the psychomotor vigilance test, respectively. Saliva samples will assess melatonin levels, and a blood sample will measure circadian time. Thermal exposures and responses will be measured by sensors and by thermography. ETHICS AND DISSEMINATION All participants will give written informed consent to participate in the study, which will be conducted in accordance with the Declaration of Helsinki. The Norwegian Regional Committee for Medical Research Ethics South-East D waivered the need for ethics approval (reference 495816). Dissemination plans include academic and lay publications, and partnerships with national and regional policymakers.
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Affiliation(s)
- Dagfinn Matre
- National Institute of Occupational Health, Oslo, Norway
| | - Mikael Sallinen
- Finnish Institute of Occupational Health, Työterveyslaitos, Finland
| | | | | | | | - Fred Haugen
- National Institute of Occupational Health, Oslo, Norway
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Malhan D, Schoenrock B, Yalçin M, Blottner D, Relόgio A. Circadian regulation in aging: Implications for spaceflight and life on earth. Aging Cell 2023; 22:e13935. [PMID: 37493006 PMCID: PMC10497835 DOI: 10.1111/acel.13935] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/30/2023] [Accepted: 07/07/2023] [Indexed: 07/27/2023] Open
Abstract
Alterations in the circadian system are characteristic of aging on Earth. With the decline in physiological processes due to aging, several health concerns including vision loss, cardiovascular disorders, cognitive impairments, and muscle mass loss arise in elderly populations. Similar health risks are reported as "red flag" risks among astronauts during and after a long-term Space exploration journey. However, little is known about the common molecular alterations underlying terrestrial aging and space-related aging in astronauts, and controversial conclusions have been recently reported. In light of the regulatory role of the circadian clock in the maintenance of human health, we review here the overlapping role of the circadian clock both on aging on Earth and spaceflight with a focus on the four most affected systems: visual, cardiovascular, central nervous, and musculoskeletal systems. In this review, we briefly introduce the regulatory role of the circadian clock in specific cellular processes followed by alterations in those processes due to aging. We next summarize the known molecular alterations associated with spaceflight, highlighting involved clock-regulated genes in space flown Drosophila, nematodes, small mammals, and astronauts. Finally, we discuss common genes that are altered in terms of their expression due to aging on Earth and spaceflight. Altogether, the data elaborated in this review strengthen our hypothesis regarding the timely need to include circadian dysregulation as an emerging hallmark of aging on Earth and beyond.
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Affiliation(s)
- Deeksha Malhan
- Institute for Systems Medicine and Faculty of Human MedicineMSH Medical School HamburgHamburgGermany
| | - Britt Schoenrock
- Institute of Integrative NeuroanatomyCharité‐Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Müge Yalçin
- Institute for Systems Medicine and Faculty of Human MedicineMSH Medical School HamburgHamburgGermany
- Institute for Theoretical Biology (ITB)Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
- Molecular Cancer Research Center (MKFZ), Medical Department of Hematology, Oncology, and Tumour Immunology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Dieter Blottner
- Institute of Integrative NeuroanatomyCharité‐Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
- Neuromuscular System and Neuromuscular SignalingBerlin Center of Space Medicine & Extreme EnvironmentsBerlinGermany
| | - Angela Relόgio
- Institute for Systems Medicine and Faculty of Human MedicineMSH Medical School HamburgHamburgGermany
- Institute for Theoretical Biology (ITB)Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
- Molecular Cancer Research Center (MKFZ), Medical Department of Hematology, Oncology, and Tumour Immunology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
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Roach ST, Ford MC, Simhambhatla V, Loutrianakis V, Farah H, Li Z, Periandri EM, Abdalla D, Huang I, Kalra A, Shaw PJ. Sleep deprivation, sleep fragmentation, and social jet lag increase temperature preference in Drosophila. Front Neurosci 2023; 17:1175478. [PMID: 37274220 PMCID: PMC10237294 DOI: 10.3389/fnins.2023.1175478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/02/2023] [Indexed: 06/06/2023] Open
Abstract
Despite the fact that sleep deprivation substantially affects the way animals regulate their body temperature, the specific mechanisms behind this phenomenon are not well understood. In both mammals and flies, neural circuits regulating sleep and thermoregulation overlap, suggesting an interdependence that may be relevant for sleep function. To investigate this relationship further, we exposed flies to 12 h of sleep deprivation, or 48 h of sleep fragmentation and evaluated temperature preference in a thermal gradient. Flies exposed to 12 h of sleep deprivation chose warmer temperatures after sleep deprivation. Importantly, sleep fragmentation, which prevents flies from entering deeper stages of sleep, but does not activate sleep homeostatic mechanisms nor induce impairments in short-term memory also resulted in flies choosing warmer temperatures. To identify the underlying neuronal circuits, we used RNAi to knock down the receptor for Pigment dispersing factor, a peptide that influences circadian rhythms, temperature preference and sleep. Expressing UAS-PdfrRNAi in subsets of clock neurons prevented sleep fragmentation from increasing temperature preference. Finally, we evaluated temperature preference after flies had undergone a social jet lag protocol which is known to disrupt clock neurons. In this protocol, flies experience a 3 h light phase delay on Friday followed by a 3 h light advance on Sunday evening. Flies exposed to social jet lag exhibited an increase in temperature preference which persisted for several days. Our findings identify specific clock neurons that are modulated by sleep disruption to increase temperature preference. Moreover, our data indicate that temperature preference may be a more sensitive indicator of sleep disruption than learning and memory.
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Affiliation(s)
- S. Tanner Roach
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, United States
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Melanie C. Ford
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Vikram Simhambhatla
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Vasilios Loutrianakis
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Hamza Farah
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Zhaoyi Li
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Erica M. Periandri
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Dina Abdalla
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Irene Huang
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Arjan Kalra
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Paul J. Shaw
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
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10
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Bansal S, Lin S. Transcriptional Genetically Encoded Calcium Indicators in Drosophila. Cold Spring Harb Protoc 2023; 2023:8-18. [PMID: 36167674 DOI: 10.1101/pdb.top107797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Knowing which neurons are active during behavior is a crucial step toward understanding how nervous systems work. Neuronal activation is generally accompanied by an increase in intracellular calcium levels. Therefore, intracellular calcium levels are widely used as a proxy for neuronal activity. Many types of synthetic components and bioluminescent or fluorescent proteins that report transient and long-term changes in intracellular calcium levels have been developed over the past 60 years. Calcium indicators that enable imaging of the dynamic activity of a large ensemble of neurons in behaving animals have revolutionized the field of neuroscience. Among these, transcription-based genetically encoded calcium indicators (transcriptional GECIs) have proven easy to use and do not depend on sophisticated imaging systems, offering unique advantages over other types of calcium indicators. Here, we describe the two currently available fly transcriptional GECIs-calcium-dependent nuclear import of LexA (CaLexA) and transcriptional reporter of intracellular calcium (TRIC)-and review studies that have used them. In the accompanying protocol, we present step-by-step details for generating CaLexA- and TRIC-ready flies and for imaging CaLexA and TRIC signals in dissected brains after experimental manipulations of intact free-moving flies.
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Affiliation(s)
- Sonia Bansal
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Suewei Lin
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
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11
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Park C, Hwang J, Ahn JW, Park YJ. Perceiving "Complex Autonomous Systems" in Symmetry Dynamics: Elementary Coordination Embedding in Circadian Cycles. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 20:166. [PMID: 36612486 PMCID: PMC9819880 DOI: 10.3390/ijerph20010166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/06/2022] [Accepted: 12/17/2022] [Indexed: 06/17/2023]
Abstract
This study explored the biological autonomy and control of function in circumstances that assessed the presumed relationship of an organism with an environmental cycle. An understanding of this behavior appeals to the organism-environment system rather than just the organism. Therefore, we sought to uncover the laws underlying end-directed capabilities by measuring biological characteristics (motor synchrony) in an environmental cycle (circadian temperature). We found that the typical elementary coordination (bimanual) stability measure varied significantly as a function of the day-night temperature cycle. While circadian effects under artificially manipulated temperatures were not straightforward during the day-night temperature cycle, the circadian effect divided by the ordinary circadian rhythm remained constant during the day-night cycle. Our observation of this direct, robust relationship between the biological characteristics (body temperature and motor synchrony) and environmental processes (circadian temperature cycle) could mirror the adaptation of our biological system to the environment.
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Affiliation(s)
- Chulwook Park
- Institute of Sport Science, Seoul National University, Seoul 08826, Republic of Korea
- International Institute for Applied Systems Analysis (IIASA), A-2361 Laxenburg, Austria
- Okinawa Institute of Science and Technology (OIST), m1919-1, Okinawa 904-0495, Japan
| | - Jean Hwang
- Department of Physical Education, College of Education, Jeonbuk National University, Jeonju 54896, Republic of Korea
| | - Jae Woong Ahn
- Department of Physical Education, College of Education, Jeonbuk National University, Jeonju 54896, Republic of Korea
| | - Yu Jin Park
- Department of Physical Education, College of Education, Jeonbuk National University, Jeonju 54896, Republic of Korea
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12
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Light triggers a network switch between circadian morning and evening oscillators controlling behaviour during daily temperature cycles. PLoS Genet 2022; 18:e1010487. [PMID: 36367867 PMCID: PMC9683589 DOI: 10.1371/journal.pgen.1010487] [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: 05/30/2022] [Revised: 11/23/2022] [Accepted: 10/20/2022] [Indexed: 11/13/2022] Open
Abstract
Proper timing of rhythmic locomotor behavior is the consequence of integrating environmental conditions and internal time dictated by the circadian clock. Rhythmic environmental input like daily light and temperature changes (called Zeitgeber) reset the molecular clock and entrain it to the environmental time zone the organism lives in. Furthermore, depending on the absolute temperature or light intensity, flies exhibit their main locomotor activity at different times of day, i.e., environmental input not only entrains the circadian clock but also determines the phase of a certain behavior. To understand how the brain clock can distinguish between (or integrate) an entraining Zeitgeber and environmental effects on activity phase, we attempted to entrain the clock with a Zeitgeber different from the environmental input used for phasing the behavior. 150 clock neurons in the Drosophila melanogaster brain control different aspects of the daily activity rhythms and are organized in various clusters. During regular 12 h light: 12 h dark cycles at constant mild temperature (LD 25°C, LD being the Zeitgeber), so called morning oscillator (MO) neurons control the increase of locomotor activity just before lights-on, while evening oscillator (EO) neurons regulate the activity increase at the end of the day, a few hours before lights-off. Here, using 12 h: 12 h 25°C:16°C temperature cycles as Zeitgeber, we attempted to look at the impact of light on phasing locomotor behavior. While in constant light and 25°C:16°C temperature cycles (LLTC), flies show an unimodal locomotor activity peak in the evening, during the same temperature cycle, but in the absence of light (DDTC), the phase of the activity peak is shifted to the morning. Here, we show that the EO is necessary for synchronized behavior in LLTC but not for entraining the molecular clock of the other clock neuronal groups, while the MO controls synchronized morning activity in DDTC. Interestingly, our data suggest that the influence of the EO on the synchronization increases depending on the length of the photoperiod (constant light vs 12 h of light). Hence, our results show that effects of different environmental cues on clock entrainment and activity phase can be separated, allowing to decipher their integration by the circadian clock. “If a clock is to provide information involved in controlling important functions, then clearly it must be reasonably reliable” said Colin Pittendrigh, one of the chronobiology pioneers in 1954. The circadian clock allows organisms to synchronize with their ecological niche. For this, the circadian clock uses rhythmic environmental parameters (Zeitgeber), the main ones being light and temperature. Hence, Colin Pittendrigh posted a still unresolved enigma in chronobiology. How can a clock be reliable when its resetting depends on environmental fluctuations that are not so reliable? Both, light and temperature vary a lot on a day-to-day basis, and animals respond to these variations depending on the time of day. Here, we propose a new model where the molecular clock resets to environmental cycles in a robust and independent manner, while the underlying neuronal oscillatory network switches its balance towards specific oscillators depending on the environmental condition thereby leading to distinct behavioral adaptation. To proof this proposed dogma in fruit flies, using temperature cycles as Zeitgeber, we demonstrate a light-induced switch of the network balance. Hence, we supply a foundation that in the future will help to understand how animals use their circadian clock to adapt their behavior to environmental changes.
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13
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Yuan Y, Padilla MA, Clark D, Yadlapalli S. Streamlined single-molecule RNA-FISH of core clock mRNAs in clock neurons in whole mount Drosophila brains. Front Physiol 2022; 13:1051544. [PMID: 36439243 PMCID: PMC9682093 DOI: 10.3389/fphys.2022.1051544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 10/17/2022] [Indexed: 11/10/2022] Open
Abstract
Circadian clocks are ∼24-h timekeepers that control rhythms in almost all aspects of our behavior and physiology. While it is well known that subcellular localization of core clock proteins plays a critical role in circadian regulation, very little is known about the spatiotemporal organization of core clock mRNAs and its role in generating ∼24-h circadian rhythms. Here we describe a streamlined single molecule Fluorescence In Situ Hybridization (smFISH) protocol and a fully automated analysis pipeline to precisely quantify the number and subcellular location of mRNAs of Clock, a core circadian transcription factor, in individual clock neurons in whole mount Drosophila adult brains. Specifically, we used ∼48 fluorescent oligonucleotide probes that can bind to an individual Clock mRNA molecule, which can then be detected as a diffraction-limited spot. Further, we developed a machine learning-based approach for 3-D cell segmentation, based on a pretrained encoder-decoder convolutional neural network, to automatically identify the cytoplasm and nuclei of clock neurons. We combined our segmentation model with a spot counting algorithm to detect Clock mRNA spots in individual clock neurons. Our results demonstrate that the number of Clock mRNA molecules cycle in large ventral lateral clock neurons (lLNvs) with peak levels at ZT4 (4 h after lights are turned on) with ∼80 molecules/neuron and trough levels at ZT16 with ∼30 molecules/neuron. Our streamlined smFISH protocol and deep learning-based analysis pipeline can be employed to quantify the number and subcellular location of any mRNA in individual clock neurons in Drosophila brains. Further, this method can open mechanistic and functional studies into how spatiotemporal localization of clock mRNAs affect circadian rhythms.
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Affiliation(s)
- Ye Yuan
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Ye Yuan, ; Swathi Yadlapalli,
| | - Marc-Antonio Padilla
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
| | - Dunham Clark
- Cell and Developmental Biology Department, University of Michigan, Ann Arbor, MI, United States
| | - Swathi Yadlapalli
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, United States
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
- Cell and Developmental Biology Department, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Ye Yuan, ; Swathi Yadlapalli,
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14
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Abstract
Sleep is a fundamental, evolutionarily conserved, plastic behavior that is regulated by circadian and homeostatic mechanisms as well as genetic factors and environmental factors, such as light, humidity, and temperature. Among environmental cues, temperature plays an important role in the regulation of sleep. This review presents an overview of thermoreception in animals and the neural circuits that link this process to sleep. Understanding the influence of temperature on sleep can provide insight into basic physiologic processes that are required for survival and guide strategies to manage sleep disorders.
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15
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Delventhal R, Barber AF. Sensory integration: Time and temperature regulate fly siesta. Curr Biol 2022; 32:R1020-R1022. [PMID: 36220091 DOI: 10.1016/j.cub.2022.08.072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Temperatures outside the preferred range require flies to acutely adjust their behavior. A new study finds that heat-sensing neurons provide input to fly circadian clock neurons to extend the daytime siesta, allowing flies to sleep through excessive daytime heat.
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Affiliation(s)
- Rebecca Delventhal
- Department of Biology, Lake Forest College, 555 North Sheridan Road, Lake Forest, IL 60045, USA
| | - Annika F Barber
- Waksman Institute, Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, 190 Frelinghuysen Rd., Piscataway, NJ 08854, USA.
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16
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Alpert MH, Gil H, Para A, Gallio M. A thermometer circuit for hot temperature adjusts Drosophila behavior to persistent heat. Curr Biol 2022; 32:4079-4087.e4. [PMID: 35981537 PMCID: PMC9529852 DOI: 10.1016/j.cub.2022.07.060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/15/2022] [Accepted: 07/20/2022] [Indexed: 11/22/2022]
Abstract
Small poikilotherms such as the fruit fly Drosophila depend on absolute temperature measurements to identify external conditions that are above (hot) or below (cold) their preferred range and to react accordingly. Hot and cold temperatures have a different impact on fly activity and sleep, but the circuits and mechanisms that adjust behavior to specific thermal conditions are not well understood. Here, we use patch-clamp electrophysiology to show that internal thermosensory neurons located within the fly head capsule (the AC neurons1) function as a thermometer active in the hot range. ACs exhibit sustained firing rates that scale with absolute temperature-but only for temperatures above the fly's preferred ∼25°C (i.e., "hot" temperature). We identify ACs in the fly brain connectome and demonstrate that they target a single class of circadian neurons, the LPNs.2 LPNs receive excitatory drive from ACs and respond robustly to hot stimuli, but their responses do not exclusively rely on ACs. Instead, LPNs receive independent drive from thermosensory neurons of the fly antenna via a new class of second-order projection neurons (TPN-IV). Finally, we show that silencing LPNs blocks the restructuring of daytime "siesta" sleep, which normally occurs in response to persistent heat. Our previous work described a distinct thermometer circuit for cold temperature.3 Together, the results demonstrate that the fly nervous system separately encodes and relays absolute hot and cold temperature information, show how patterns of sleep and activity can be adapted to specific temperature conditions, and illustrate how persistent drive from sensory pathways can impact behavior on extended temporal scales.
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Affiliation(s)
- Michael H Alpert
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Hamin Gil
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Alessia Para
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Marco Gallio
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.
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17
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Greening L, McBride S. A Review of Equine Sleep: Implications for Equine Welfare. Front Vet Sci 2022; 9:916737. [PMID: 36061116 PMCID: PMC9428463 DOI: 10.3389/fvets.2022.916737] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Sleep is a significant biological requirement for all living mammals due to its restorative properties and its cognitive role in memory consolidation. Sleep is ubiquitous amongst all mammals but sleep profiles differ between species dependent upon a range of biological and environmental factors. Given the functional importance of sleep, it is important to understand these differences in order to ensure good physical and psychological wellbeing for domesticated animals. This review focuses specifically on the domestic horse and aims to consolidate current information on equine sleep, in relation to other species, in order to (a) identify both quantitatively and qualitatively what constitutes normal sleep in the horse, (b) identify optimal methods to measure equine sleep (logistically and in terms of accuracy), (c) determine whether changes in equine sleep quantity and quality reflect changes in the animal's welfare, and (d) recognize the primary factors that affect the quantity and quality of equine sleep. The review then discusses gaps in current knowledge and uses this information to identify and set the direction of future equine sleep research with the ultimate aim of improving equine performance and welfare. The conclusions from this review are also contextualized within the current discussions around the “social license” of horse use from a welfare perspective.
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Affiliation(s)
- Linda Greening
- Hartpury University and Hartpury College, Gloucester, United Kingdom
- *Correspondence: Linda Greening
| | - Sebastian McBride
- Institute of Biological, Environmental and Rural Science, Aberystwyth University, Aberystwyth, United Kingdom
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18
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Shafer OT, Gutierrez GJ, Li K, Mildenhall A, Spira D, Marty J, Lazar AA, Fernandez MDLP. ---Connectomic analysis of the Drosophila lateral neuron clock cells reveals the synaptic basis of functional pacemaker classes. eLife 2022; 11:79139. [PMID: 35766361 PMCID: PMC9365390 DOI: 10.7554/elife.79139] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/29/2022] [Indexed: 11/23/2022] Open
Abstract
The circadian clock orchestrates daily changes in physiology and behavior to ensure internal temporal order and optimal timing across the day. In animals, a central brain clock coordinates circadian rhythms throughout the body and is characterized by a remarkable robustness that depends on synaptic connections between constituent neurons. The clock neuron network of Drosophila, which shares network motifs with clock networks in the mammalian brain yet is built of many fewer neurons, offers a powerful model for understanding the network properties of circadian timekeeping. Here, we report an assessment of synaptic connectivity within a clock network, focusing on the critical lateral neuron (LN) clock neuron classes within the Janelia hemibrain dataset. Our results reveal that previously identified anatomical and functional subclasses of LNs represent distinct connectomic types. Moreover, we identify a small number of non-clock cell subtypes representing highly synaptically coupled nodes within the clock neuron network. This suggests that neurons lacking molecular timekeeping likely play integral roles within the circadian timekeeping network. To our knowledge, this represents the first comprehensive connectomic analysis of a circadian neuronal network. Most organisms on Earth possess an internal timekeeping system which ensures that bodily processes such as sleep, wakefulness or digestion take place at the right time. These precise daily rhythms are kept in check by a master clock in the brain. There, thousands of neurons – some of which carrying an internal ‘molecular clock’ – connect to each other through structures known as synapses. Exactly how the resulting network is organised to support circadian timekeeping remains unclear. To explore this question, Shafer, Gutierrez et al. focused on fruit flies, as recent efforts have systematically mapped every neuron and synaptic connection in the brain of this model organism. Analysing available data from the hemibrain connectome project at Janelia revealed that that the neurons with the most important timekeeping roles were in fact forming the fewest synapses within the network. In addition, neurons without internal molecular clocks mediated strong synaptic connections between those that did, suggesting that ‘clockless’ cells still play an integral role in circadian timekeeping. With this research, Shafer, Gutierrez et al. provide unexpected insights into the organisation of the master body clock. Better understanding the networks that underpin circadian rhythms will help to grasp how and why these are disrupted in obesity, depression and Alzheimer’s disease.
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Affiliation(s)
- Orie T Shafer
- Advanced Science Research Center, City University of New York, New York, United States
| | - Gabrielle J Gutierrez
- Center for Theoretical Neuroscience, Columbia University, New York City, United States
| | - Kimberly Li
- Department of Neuroscience and Behavior, Barnard College, New York, United States
| | - Amber Mildenhall
- Department of Neuroscience and Behavior, Barnard College, New York, United States
| | - Daphna Spira
- Center for Theoretical Neuroscience, Columbia University, New York City, United States
| | - Jonathan Marty
- Department of Electrical Engineering, Columbia University, New York, United States
| | - Aurel A Lazar
- Department of Electrical Engineering, Columbia University, New York, United States
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19
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Recurrent circadian circuitry regulates central brain activity to maintain sleep. Neuron 2022; 110:2139-2154.e5. [PMID: 35525241 DOI: 10.1016/j.neuron.2022.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 03/14/2022] [Accepted: 04/07/2022] [Indexed: 12/19/2022]
Abstract
Animal brains have discrete circadian neurons, but little is known about how they are coordinated to influence and maintain sleep. Here, through a systematic optogenetic screening, we identified a subtype of uncharacterized circadian DN3 neurons that is strongly sleep promoting in Drosophila. These anterior-projecting DN3s (APDN3s) receive signals from DN1 circadian neurons and then output to newly identified noncircadian "claw" neurons (CLs). CLs have a daily Ca2+ cycle, which peaks at night and correlates with DN1 and DN3 Ca2+ cycles. The CLs feedback onto a subset of DN1s to form a positive recurrent loop that maintains sleep. Using trans-synaptic photoactivatable green fluorescent protein (PA-GFP) tracing and functional in vivo imaging, we demonstrated that the CLs drive sleep by interacting with and releasing acetylcholine onto the mushroom body γ lobe. Taken together, the data identify a novel self-reinforcing loop within the circadian network and a new sleep-promoting neuropile that are both essential for maintaining normal sleep.
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20
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Zou S, Jiao X, Liu J, Qi D, Pei X, Lu D, Huang S, Li Z. High-Fat Nutritional Challenge Reshapes Circadian Signatures in Murine Extraorbital Lacrimal Glands. Invest Ophthalmol Vis Sci 2022; 63:23. [PMID: 35588356 PMCID: PMC9123521 DOI: 10.1167/iovs.63.5.23] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose A high-fat diet (HFD) increases the risk of developing many systemic diseases; however, the effects of high fat intake on lacrimal gland functions and the molecular mechanisms underlying these effects are unknown. We explored the effects of an HFD on the circadian rhythms of the extraorbital lacrimal glands (ELGs). Methods Male C57BL/6J mice maintained on a 12/12-hour light/dark cycle were fed an ad libitum HFD or normal chow (NC) for 2 weeks. The ELGs were collected from euthanized animals every 3 hours throughout the circadian cycle (24 hours). Using high-throughput RNA-sequencing (RNA-Seq), we studied the circadian transcriptomic profile of the ELGs. Circadian oscillations in cell size, secretion response, lipid deposition, and immune cell trafficking of the ELGs were also analyzed. Results An HFD modulated the circadian transcriptomic profile of the ELGs, including the composition, phase, and amplitude of cyclical transcript oscillations, and affected the associated signaling pathways at spatiotemporal levels. HFD feeding significantly altered the normal rhythmic oscillations of ELG cell size, immune cell trafficking, secretion response, and lipid deposition. After dietary reversal in HFD-fed animals, the activity, core temperature, and lipid accumulation in lacrimal glands recovered partially to the level of NC-fed animals. However, the average cell size of the ELGs, the recruitment of immune cells, and the rhythm of lacrimal secretion did not return to the levels of the NC-fed group. Conclusions HFD perturbation interferes with the cyclical transcriptomic profile, cell size, immune cell trafficking, and secretion function of the ELGs with a strikingly high sensitivity.
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Affiliation(s)
- Sen Zou
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou City, China
| | - Xinwei Jiao
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou City, China
| | - Jiangman Liu
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou City, China
| | - Di Qi
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou City, China
| | - Xiaoting Pei
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou City, China
| | - Dingli Lu
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou City, China
| | - Shenzhen Huang
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou City, China
| | - Zhijie Li
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou City, China
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21
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Reinhard N, Schubert FK, Bertolini E, Hagedorn N, Manoli G, Sekiguchi M, Yoshii T, Rieger D, Helfrich-Förster C. The Neuronal Circuit of the Dorsal Circadian Clock Neurons in Drosophila melanogaster. Front Physiol 2022; 13:886432. [PMID: 35574472 PMCID: PMC9100938 DOI: 10.3389/fphys.2022.886432] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 03/28/2022] [Indexed: 11/30/2022] Open
Abstract
Drosophila’s dorsal clock neurons (DNs) consist of four clusters (DN1as, DN1ps, DN2s, and DN3s) that largely differ in size. While the DN1as and the DN2s encompass only two neurons, the DN1ps consist of ∼15 neurons, and the DN3s comprise ∼40 neurons per brain hemisphere. In comparison to the well-characterized lateral clock neurons (LNs), the neuroanatomy and function of the DNs are still not clear. Over the past decade, numerous studies have addressed their role in the fly’s circadian system, leading to several sometimes divergent results. Nonetheless, these studies agreed that the DNs are important to fine-tune activity under light and temperature cycles and play essential roles in linking the output from the LNs to downstream neurons that control sleep and metabolism. Here, we used the Flybow system, specific split-GAL4 lines, trans-Tango, and the recently published fly connectome (called hemibrain) to describe the morphology of the DNs in greater detail, including their synaptic connections to other clock and non-clock neurons. We show that some DN groups are largely heterogenous. While certain DNs are strongly connected with the LNs, others are mainly output neurons that signal to circuits downstream of the clock. Among the latter are mushroom body neurons, central complex neurons, tubercle bulb neurons, neurosecretory cells in the pars intercerebralis, and other still unidentified partners. This heterogeneity of the DNs may explain some of the conflicting results previously found about their functionality. Most importantly, we identify two putative novel communication centers of the clock network: one fiber bundle in the superior lateral protocerebrum running toward the anterior optic tubercle and one fiber hub in the posterior lateral protocerebrum. Both are invaded by several DNs and LNs and might play an instrumental role in the clock network.
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Affiliation(s)
- Nils Reinhard
- Julius Maximilian University of Würzburg, Würzburg, Germany
| | | | - Enrico Bertolini
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Würzburg, Germany
| | | | - Giulia Manoli
- Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Manabu Sekiguchi
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Dirk Rieger
- Julius Maximilian University of Würzburg, Würzburg, Germany
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22
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Chen SC, Tang X, Goda T, Umezaki Y, Riley AC, Sekiguchi M, Yoshii T, Hamada FN. Dorsal clock networks drive temperature preference rhythms in Drosophila. Cell Rep 2022; 39:110668. [PMID: 35417715 PMCID: PMC9109596 DOI: 10.1016/j.celrep.2022.110668] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 09/21/2021] [Accepted: 03/22/2022] [Indexed: 11/24/2022] Open
Abstract
Animals display a body temperature rhythm (BTR). Little is known about the mechanisms by which a rhythmic pattern of BTR is regulated and how body temperature is set at different times of the day. As small ectotherms, Drosophila exhibit a daily temperature preference rhythm (TPR), which generates BTR. Here, we demonstrate dorsal clock networks that play essential roles in TPR. Dorsal neurons 2 (DN2s) are the main clock for TPR. We find that DN2s and posterior DN1s (DN1ps) contact and the extent of contacts increases during the day and that the silencing of DN2s or DN1ps leads to a lower temperature preference. The data suggest that temporal control of the microcircuit from DN2s to DN1ps contributes to TPR regulation. We also identify anterior DN1s (DN1as) as another important clock for TPR. Thus, we show that the DN networks predominantly control TPR and determine both a rhythmic pattern and preferred temperatures. The body temperature rhythm (BTR) is vital for maintaining homeostasis. Drosophila exhibit a daily temperature preference rhythm (TPR), which generates BTR. Chen et al. show that dorsal clock neurons in the brain form a time-dependent network and govern TPR by regulating a rhythmic pattern and a temperature setpoint.
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Affiliation(s)
- Shyh-Chi Chen
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Xin Tang
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Tadahiro Goda
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA
| | - Yujiro Umezaki
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA
| | - Abigail C Riley
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Manabu Sekiguchi
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Fumika N Hamada
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA.
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23
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Lamaze A, Chen C, Leleux S, Xu M, George R, Stanewsky R. A natural timeless polymorphism allowing circadian clock synchronization in "white nights". Nat Commun 2022; 13:1724. [PMID: 35361756 PMCID: PMC8971440 DOI: 10.1038/s41467-022-29293-6] [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: 03/06/2020] [Accepted: 03/08/2022] [Indexed: 11/09/2022] Open
Abstract
Daily temporal organisation offers a fitness advantage and is determined by an interplay between environmental rhythms and circadian clocks. While light:dark cycles robustly synchronise circadian clocks, it is not clear how animals experiencing only weak environmental cues deal with this problem. Like humans, Drosophila originate in sub-Saharan Africa and spread North up to the polar circle, experiencing long summer days or even constant light (LL). LL disrupts clock function, due to constant activation of CRYPTOCHROME, which induces degradation of the clock protein TIMELESS (TIM), but temperature cycles are able to overcome these deleterious effects of LL. We show here that for this to occur a recently evolved natural timeless allele (ls-tim) is required, encoding the less light-sensitive L-TIM in addition to S-TIM, the only form encoded by the ancient s-tim allele. We show that only ls-tim flies can synchronise their behaviour to semi-natural conditions typical for Northern European summers, suggesting that this functional gain is driving the Northward ls-tim spread. The genus Drosophila originate in subSaharan Africa and spread North up to the polar circle where they experience long days in the summer or even constant light. Here, the authors show that a form of the TIMELESS protein enables flies to synchronise their behavioural activity to long summer days
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Affiliation(s)
- Angelique Lamaze
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany.
| | - Chenghao Chen
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA. .,Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA.
| | - Solene Leleux
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany
| | - Min Xu
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA
| | - Rebekah George
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany
| | - Ralf Stanewsky
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany.
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24
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Meiselman MR, Alpert MH, Cui X, Shea J, Gregg I, Gallio M, Yapici N. Recovery from cold-induced reproductive dormancy is regulated by temperature-dependent AstC signaling. Curr Biol 2022; 32:1362-1375.e8. [PMID: 35176227 PMCID: PMC8969192 DOI: 10.1016/j.cub.2022.01.061] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/09/2021] [Accepted: 01/21/2022] [Indexed: 11/25/2022]
Abstract
Animals have evolved a variety of behaviors to cope with adverse environmental conditions. Similar to other insects, the fly, Drosophila melanogaster, responds to sustained cold by reducing its metabolic rate and arresting its reproduction. Here, we show that a subset of dorsal neurons (DN3s) that express the neuropeptide allatostatin C (AstC) facilitates recovery from cold-induced reproductive dormancy. The activity of AstC-expressing DN3s, as well as AstC peptide levels, are suppressed by cold. Cold temperature also impacts AstC levels in other Drosophila species and mosquitoes, Aedes aegypti, and Anopheles stephensi. The stimulatory effect of AstC on egg production is mediated by cholinergic AstC-R2 neurons. Our results demonstrate that DN3s coordinate female reproductive capacity with environmental temperature via AstC signaling. AstC/AstC-R2 is conserved across many insect species and their role in regulating female reproductive capacity makes them an ideal target for controlling the population of agricultural pests and human disease vectors.
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Affiliation(s)
- Matthew R Meiselman
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Michael H Alpert
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Xinyue Cui
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Jamien Shea
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Ian Gregg
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Marco Gallio
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Nilay Yapici
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA.
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25
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Iyengar AS, Kulkarni R, Sheeba V. Under warm ambient conditions, Drosophila melanogaster suppresses nighttime activity via the neuropeptide pigment dispersing factor. GENES, BRAIN, AND BEHAVIOR 2022; 21:e12802. [PMID: 35285135 PMCID: PMC9744560 DOI: 10.1111/gbb.12802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 11/26/2022]
Abstract
Rhythmic locomotor behaviour of flies is controlled by an endogenous time-keeping mechanism, the circadian clock, and is influenced by environmental temperatures. Flies inherently prefer cool temperatures around 25°C, and under such conditions, time their locomotor activity to occur at dawn and dusk. Under relatively warmer conditions such as 30°C, flies shift their activity into the night, advancing their morning activity bout into the early morning, before lights-ON, and delaying their evening activity into early night. The molecular basis for such temperature-dependent behavioural modulation has been associated with core circadian clock genes, but the neuronal basis is not yet clear. Under relatively cool temperatures such as 25°C, the role of the circadian pacemaker ventrolateral neurons (LNvs), along with a major neuropeptide secreted by them, pigment dispersing factor (PDF), has been showed in regulating various aspects of locomotor activity rhythms. However, the role of the LNvs and PDF in warm temperature-mediated behavioural modulation has not been explored. We show here that flies lacking proper PDF signalling or the LNvs altogether, cannot suppress their locomotor activity resulting in loss of sleep during the middle of the night, and thus describe a novel role for PDF signalling and the LNvs in behavioural modulation under warm ambient conditions. In a rapidly warming world, such behavioural plasticity may enable organisms to respond to harsh temperatures in the environment.
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Affiliation(s)
- Aishwariya Srikala Iyengar
- Chronobiology and Behavioural Neurogenetics LaboratoryNeuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBangaloreIndia
| | - Rutvij Kulkarni
- Chronobiology and Behavioural Neurogenetics LaboratoryNeuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBangaloreIndia
| | - Vasu Sheeba
- Chronobiology and Behavioural Neurogenetics LaboratoryNeuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBangaloreIndia
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26
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Feng G, Zhang H, Zhu X, Zhang J, Fang J. Fluorescence Thermometer: Intermediation of the Fontal Temperature and Light. Biomater Sci 2022; 10:1855-1882. [DOI: 10.1039/d1bm01912k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rapid advance of thermal materials and fluorescence spectroscopy has extensively promoted micro-scale fluorescence thermometry development in recent years. Based on the advantages of fast response, high sensitivity, simple operation,...
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27
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Reinhard N, Bertolini E, Saito A, Sekiguchi M, Yoshii T, Rieger D, Helfrich-Förster C. The lateral posterior clock neurons (LPN) of Drosophila melanogaster express three neuropeptides and have multiple connections within the circadian clock network and beyond. J Comp Neurol 2021; 530:1507-1529. [PMID: 34961936 DOI: 10.1002/cne.25294] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 11/12/2022]
Abstract
Drosophila's lateral posterior neurons (LPNs) belong to a small group of circadian clock neurons that is so far not characterized in detail. Thanks to a new highly specific split-Gal4 line, here we describe LPNs' morphology in fine detail, their synaptic connections, daily bimodal expression of neuropeptides, and propose a putative role of this cluster in controlling daily activity and sleep patterns. We found that the three LPNs are heterogeneous. Two of the neurons with similar morphology arborize in the superior medial and lateral protocerebrum and most likely promote sleep. One unique, possibly wakefulness-promoting, neuron with wider arborizations extends from the superior lateral protocerebrum toward the anterior optic tubercle. Both LPN types exhibit manifold connections with the other circadian clock neurons, especially with those that control the flies' morning and evening activity (M- and E-neurons, respectively). In addition, they form synaptic connections with neurons of the mushroom bodies, the fan-shaped body, and with many additional still unidentified neurons. We found that both LPN types rhythmically express three neuropeptides, Allostatin A, Allostatin C, and Diuretic Hormone 31 with maxima in the morning and the evening. The three LPN neuropeptides may, furthermore, signal to the insect hormonal center in the pars intercerebralis and contribute to rhythmic modulation of metabolism, feeding, and reproduction. We discuss our findings in the light of anatomical details gained by the recently published hemibrain of a single female fly on the electron microscopic level and of previous functional studies concerning the LPN. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Nils Reinhard
- Neurobiology and Genetics, Biocenter, University of Würzburg, Germany
| | - Enrico Bertolini
- Neurobiology and Genetics, Biocenter, University of Würzburg, Germany
| | - Aika Saito
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Manabu Sekiguchi
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Dirk Rieger
- Neurobiology and Genetics, Biocenter, University of Würzburg, Germany
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28
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Perception of Daily Time: Insights from the Fruit Flies. INSECTS 2021; 13:insects13010003. [PMID: 35055846 PMCID: PMC8780729 DOI: 10.3390/insects13010003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/21/2021] [Accepted: 12/07/2021] [Indexed: 11/17/2022]
Abstract
We create mental maps of the space that surrounds us; our brains also compute time—in particular, the time of day. Visual, thermal, social, and other cues tune the clock-like timekeeper. Consequently, the internal clock synchronizes with the external day-night cycles. In fact, daylength itself varies, causing the change of seasons and forcing our brain clock to accommodate layers of plasticity. However, the core of the clock, i.e., its molecular underpinnings, are highly resistant to perturbations, while the way animals adapt to the daily and annual time shows tremendous biological diversity. How can this be achieved? In this review, we will focus on 75 pairs of clock neurons in the Drosophila brain to understand how a small neural network perceives and responds to the time of the day, and the time of the year.
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29
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Mechanosensory Stimulation via Nanchung Expressing Neurons Can Induce Daytime Sleep in Drosophila. J Neurosci 2021; 41:9403-9418. [PMID: 34635540 DOI: 10.1523/jneurosci.0400-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 11/21/2022] Open
Abstract
The neuronal and genetic bases of sleep, a phenomenon considered crucial for well-being of organisms, has been under investigation using the model organism Drosophila melanogaster Although sleep is a state where sensory threshold for arousal is greater, it is known that certain kinds of repetitive sensory stimuli, such as rocking, can indeed promote sleep in humans. Here we report that orbital motion-aided mechanosensory stimulation promotes sleep of male and female Drosophila, independent of the circadian clock, but controlled by the homeostatic system. Mechanosensory receptor nanchung (Nan)-expressing neurons in the chordotonal organs mediate this sleep induction: flies in which these neurons are either silenced or ablated display significantly reduced sleep induction on mechanosensory stimulation. Transient activation of the Nan-expressing neurons also enhances sleep levels, confirming the role of these neurons in sleep induction. We also reveal that certain regions of the antennal mechanosensory and motor center in the brain are involved in conveying information from the mechanosensory structures to the sleep centers. Thus, we show, for the first time, that a circadian clock-independent pathway originating from peripherally distributed mechanosensors can promote daytime sleep of flies Drosophila melanogaster SIGNIFICANCE STATEMENT Our tendency to fall asleep in moving vehicles or the practice of rocking infants to sleep suggests that slow rhythmic movement can induce sleep, although we do not understand the mechanistic basis of this phenomenon. We find that gentle orbital motion can induce behavioral quiescence even in flies, a highly genetically tractable system for sleep studies. We demonstrate that this is indeed true sleep based on its rapid reversibility by sensory stimulation, enhanced arousal threshold, and homeostatic control. Furthermore, we demonstrate that mechanosensory neurons expressing a TRPV channel nanchung, located in the antennae and chordotonal organs, mediate orbital motion-induced sleep by communicating with antennal mechanosensory motor centers, which in turn may project to sleep centers in the brain.
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30
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Nettnin EA, Sallese TR, Nasseri A, Saurabh S, Cavanaugh DJ. Dorsal clock neurons in Drosophila sculpt locomotor outputs but are dispensable for circadian activity rhythms. iScience 2021; 24:103001. [PMID: 34505011 PMCID: PMC8413890 DOI: 10.1016/j.isci.2021.103001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/04/2021] [Accepted: 08/16/2021] [Indexed: 11/26/2022] Open
Abstract
The circadian system is comprised three components: a network of core clock cells in the brain that keeps time, input pathways that entrain clock cells to the environment, and output pathways that use this information to ensure appropriate timing of physiological and behavioral processes throughout the day. Core clock cells can be divided into molecularly distinct populations that likely make unique functional contributions. Here we clarify the role of the dorsal neuron 1 (DN1) population of clock neurons in the transmission of circadian information by the Drosophila core clock network. Using an intersectional genetic approach that allowed us to selectively and comprehensively target DN1 cells, we show that suppressing DN1 neuronal activity alters the magnitude of daily activity and sleep without affecting overt rhythmicity. This suggests that DN1 cells are dispensable for both the generation of circadian information and the propagation of this information across output circuits. Intersectional genetic approach targets DN1 cells comprehensively and selectively DN1p silencing alters distribution and amount of activity and sleep across the day DN1p cell firing is neither necessary nor sufficient for circadian activity rhythms DN1a silencing subtly alters total activity and sleep but leaves rhythmicity intact
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Affiliation(s)
- Ella A Nettnin
- Department of Biology, Loyola University Chicago, Chicago IL 60660, USA
| | - Thomas R Sallese
- Department of Biology, Loyola University Chicago, Chicago IL 60660, USA
| | - Anita Nasseri
- Department of Biology, Loyola University Chicago, Chicago IL 60660, USA
| | - Sumit Saurabh
- Department of Biology, Loyola University Chicago, Chicago IL 60660, USA
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31
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Wang Y, Zhang H, Zhang Z, Sun B, Tang C, Zhang L, Jiang Z, Ding B, Liao Y, Cai P. Simulated mobile communication frequencies (3.5 GHz) emitted by a signal generator affects the sleep of Drosophila melanogaster. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 283:117087. [PMID: 33894629 DOI: 10.1016/j.envpol.2021.117087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/12/2021] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
With the rapid development of science and technology, 5G technology will be widely used, and biosafety concerns about the effects of 5G radiofrequency radiation on health have been raised. Drosophila melanogaster was selected as the model organism for our study, in which a 3.5 GHz radiofrequency radiation (RF-EMR) environment was simulated at intensities of 0.1 W/m2, 1 W/m2, and 10 W/m2. The activity of parent male and offspring (F1) male flies was measured using a Drosophila activity monitoring system under short-term and long-term 3.5 GHz RF-EMR exposure. Core genes associated with heat stress, the circadian clock and neurotransmitters were detected by QRT-PCR technology, and the contents of GABA and glutamate were detected by UPLC-MS. The results show that short-term RF-EMR exposure increased the activity level and reduced the sleep duration while long-term RF-EMR exposure reduced the activity level and increased the sleep duration of F1 male flies. Under long-term RF-EMR, the expression of heat stress response-related hsp22, hsp26 and hsp70 genes was increased, the expression of circadian clock-related per, cyc, clk, cry, and tim genes was altered, the content of GABA and glutamate was reduced, and the expression levels of synthesis, transport and receptor genes were altered. In conclusion, long-term RF-EMR exposure enhances the heat stress response of offspring flies and then affects the expression of circadian clock and neurotransmitter genes, which leads to decreased activity, prolonged sleep duration, and improved sleep quality.
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Affiliation(s)
- Yahong Wang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of the Chinese Academy of Sciences, Beijing, PR China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China
| | - Hongying Zhang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of the Chinese Academy of Sciences, Beijing, PR China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China
| | - Ziyan Zhang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China; Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, 200031, China.
| | - Boqun Sun
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of the Chinese Academy of Sciences, Beijing, PR China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China
| | - Chao Tang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of the Chinese Academy of Sciences, Beijing, PR China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China
| | - Lu Zhang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of the Chinese Academy of Sciences, Beijing, PR China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China
| | - Zhihao Jiang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of the Chinese Academy of Sciences, Beijing, PR China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China
| | - Bo Ding
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of the Chinese Academy of Sciences, Beijing, PR China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China
| | - Yanyan Liao
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of the Chinese Academy of Sciences, Beijing, PR China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China
| | - Peng Cai
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; Xiamen Key Laboratory of Physical Environment, Xiamen, 361021, China; Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, 200031, China.
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32
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Poe AR, Mace KD, Kayser MS. Getting into rhythm: developmental emergence of circadian clocks and behaviors. FEBS J 2021; 289:6576-6588. [PMID: 34375504 DOI: 10.1111/febs.16157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 06/30/2021] [Accepted: 08/09/2021] [Indexed: 11/28/2022]
Abstract
Circadian clocks keep time to coordinate diverse behaviors and physiological functions. While molecular circadian rhythms are evident during early development, most behavioral rhythms, such as sleep-wake, do not emerge until far later. Here, we examine the development of circadian clocks, outputs, and behaviors across phylogeny, with a particular focus on Drosophila. We explore potential mechanisms for how central clocks and circadian output loci establish communication, and discuss why from an evolutionary perspective sleep-wake and other behavioral rhythms emerge long after central clocks begin keeping time.
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Affiliation(s)
- Amy R Poe
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.,Chronobiology and Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Kyla D Mace
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.,Pharmacology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew S Kayser
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.,Chronobiology and Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.,Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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33
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Xiao Y, Yuan Y, Jimenez M, Soni N, Yadlapalli S. Clock proteins regulate spatiotemporal organization of clock genes to control circadian rhythms. Proc Natl Acad Sci U S A 2021; 118:e2019756118. [PMID: 34234015 PMCID: PMC8285898 DOI: 10.1073/pnas.2019756118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Circadian clocks regulate ∼24-h oscillations in gene expression, behavior, and physiology. While the genetic and molecular mechanisms of circadian rhythms are well characterized, what remains poorly understood are the intracellular dynamics of circadian clock components and how they affect circadian rhythms. Here, we elucidate how spatiotemporal organization and dynamics of core clock proteins and genes affect circadian rhythms in Drosophila clock neurons. Using high-resolution imaging and DNA-fluorescence in situ hybridization techniques, we demonstrate that Drosophila clock proteins (PERIOD and CLOCK) are organized into a few discrete foci at the nuclear envelope during the circadian repression phase and play an important role in the subnuclear localization of core clock genes to control circadian rhythms. Specifically, we show that core clock genes, period and timeless, are positioned close to the nuclear periphery by the PERIOD protein specifically during the repression phase, suggesting that subnuclear localization of core clock genes might play a key role in their rhythmic gene expression. Finally, we show that loss of Lamin B receptor, a nuclear envelope protein, leads to disruption of PER foci and per gene peripheral localization and results in circadian rhythm defects. These results demonstrate that clock proteins play a hitherto unexpected role in the subnuclear reorganization of core clock genes to control circadian rhythms, revealing how clocks function at the subcellular level. Our results further suggest that clock protein foci might regulate dynamic clustering and spatial reorganization of clock-regulated genes over the repression phase to control circadian rhythms in behavior and physiology.
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Affiliation(s)
- Yangbo Xiao
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Ye Yuan
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109
| | - Mariana Jimenez
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Neeraj Soni
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Swathi Yadlapalli
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109;
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34
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Metabolic control of daily locomotor activity mediated by tachykinin in Drosophila. Commun Biol 2021; 4:693. [PMID: 34099879 PMCID: PMC8184744 DOI: 10.1038/s42003-021-02219-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 05/14/2021] [Indexed: 12/20/2022] Open
Abstract
Metabolism influences locomotor behaviors, but the understanding of neural curcuit control for that is limited. Under standard light-dark cycles, Drosophila exhibits bimodal morning (M) and evening (E) locomotor activities that are controlled by clock neurons. Here, we showed that a high-nutrient diet progressively extended M activity but not E activity. Drosophila tachykinin (DTk) and Tachykinin-like receptor at 86C (TkR86C)-mediated signaling was required for the extension of M activity. DTk neurons were anatomically and functionally connected to the posterior dorsal neuron 1s (DN1ps) in the clock neuronal network. The activation of DTk neurons reduced intracellular Ca2+ levels in DN1ps suggesting an inhibitory connection. The contacts between DN1ps and DTk neurons increased gradually over time in flies fed a high-sucrose diet, consistent with the locomotor behavior. DN1ps have been implicated in integrating environmental sensory inputs (e.g., light and temperature) to control daily locomotor behavior. This study revealed that DN1ps also coordinated nutrient information through DTk signaling to shape daily locomotor behavior. Lee and colleagues report the effect of a high-sucrose diet on Drosophila locomotor activity via DTk-TkR86C neuropeptide signalling. This signalling pattern appears to involve a circadian element, with pacemaker neuron involvement having a possible time-of-day effect on locomotor behaviour.
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35
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Abstract
Circadian clocks are biochemical time-keeping machines that synchronize animal behavior and physiology with planetary rhythms. In Drosophila, the core components of the clock comprise a transcription/translation feedback loop and are expressed in seven neuronal clusters in the brain. Although it is increasingly evident that the clocks in each of the neuronal clusters are regulated differently, how these clocks communicate with each other across the circadian neuronal network is less clear. Here, we review the latest evidence that describes the physical connectivity of the circadian neuronal network . Using small ventral lateral neurons as a starting point, we summarize how one clock may communicate with another, highlighting the signaling pathways that are both upstream and downstream of these clocks. We propose that additional efforts are required to understand how temporal information generated in each circadian neuron is integrated across a neuronal circuit to regulate rhythmic behavior.
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Affiliation(s)
- Myra Ahmad
- Department of Pediatrics, Division of Medical Genetics, Dalhousie University, Halifax, NS, Canada
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
| | - Wanhe Li
- Laboratory of Genetics, The Rockefeller University, New York, NY, USA
| | - Deniz Top
- Department of Pediatrics, Division of Medical Genetics, Dalhousie University, Halifax, NS, Canada
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
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36
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Jin X, Tian Y, Zhang ZC, Gu P, Liu C, Han J. A subset of DN1p neurons integrates thermosensory inputs to promote wakefulness via CNMa signaling. Curr Biol 2021; 31:2075-2087.e6. [PMID: 33740429 DOI: 10.1016/j.cub.2021.02.048] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 12/15/2020] [Accepted: 02/17/2021] [Indexed: 11/29/2022]
Abstract
Sleep is an essential and evolutionarily conserved behavior that is modulated by many environmental factors. Ambient temperature shifting usually occurs during climatic or seasonal change or travel from high-latitude area to low-latitude area that affects animal physiology. Increasing ambient temperature modulates sleep in both humans and Drosophila. Although several thermosensory molecules and neurons have been identified, the neural mechanisms that integrate temperature sensation into the sleep neural circuit remain poorly understood. Here, we reveal that prolonged increasing of ambient temperature induces a reversible sleep reduction and impaired sleep consolidation in Drosophila via activating the internal thermosensory anterior cells (ACs). ACs form synaptic contacts with a subset of posterior dorsal neuron 1 (DN1p) neurons and release acetylcholine to promote wakefulness. Furthermore, we identify that this subset of DN1ps promotes wakefulness by releasing CNMamide (CNMa) neuropeptides to inhibit the Dh44-positive pars intercerebralis (PI) neurons through CNMa receptors. Our study demonstrates that the AC-DN1p-PI neural circuit is responsible for integrating thermosensory inputs into the sleep neural circuit. Moreover, we identify the CNMa signaling pathway as a newly recognized wakefulness-promoting DN1 pathway.
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Affiliation(s)
- Xi Jin
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Yao Tian
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Zi Chao Zhang
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Pengyu Gu
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Chang Liu
- CAS Key Laboratory of Brain Connectome and Manipulation, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, China
| | - Junhai Han
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226021, China.
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37
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George R, Stanewsky R. Peripheral Sensory Organs Contribute to Temperature Synchronization of the Circadian Clock in Drosophila melanogaster. Front Physiol 2021; 12:622545. [PMID: 33603678 PMCID: PMC7884628 DOI: 10.3389/fphys.2021.622545] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/08/2021] [Indexed: 02/06/2023] Open
Abstract
Circadian clocks are cell-autonomous endogenous oscillators, generated and maintained by self-sustained 24-h rhythms of clock gene expression. In the fruit fly Drosophila melanogaster, these daily rhythms of gene expression regulate the activity of approximately 150 clock neurons in the fly brain, which are responsible for driving the daily rest/activity cycles of these insects. Despite their endogenous character, circadian clocks communicate with the environment in order to synchronize their self-sustained molecular oscillations and neuronal activity rhythms (internal time) with the daily changes of light and temperature dictated by the Earth's rotation around its axis (external time). Light and temperature changes are reliable time cues (Zeitgeber) used by many organisms to synchronize their circadian clock to the external time. In Drosophila, both light and temperature fluctuations robustly synchronize the circadian clock in the absence of the other Zeitgeber. The complex mechanisms for synchronization to the daily light-dark cycles are understood with impressive detail. In contrast, our knowledge about how the daily temperature fluctuations synchronize the fly clock is rather limited. Whereas light synchronization relies on peripheral and clock-cell autonomous photoreceptors, temperature input to the clock appears to rely mainly on sensory cells located in the peripheral nervous system of the fly. Recent studies suggest that sensory structures located in body and head appendages are able to detect temperature fluctuations and to signal this information to the brain clock. This review will summarize these studies and their implications about the mechanisms underlying temperature synchronization.
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Affiliation(s)
| | - Ralf Stanewsky
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms-Universität Münster, Münster, Germany
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38
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Li F, Lindsey JW, Marin EC, Otto N, Dreher M, Dempsey G, Stark I, Bates AS, Pleijzier MW, Schlegel P, Nern A, Takemura SY, Eckstein N, Yang T, Francis A, Braun A, Parekh R, Costa M, Scheffer LK, Aso Y, Jefferis GSXE, Abbott LF, Litwin-Kumar A, Waddell S, Rubin GM. The connectome of the adult Drosophila mushroom body provides insights into function. eLife 2020; 9:e62576. [PMID: 33315010 PMCID: PMC7909955 DOI: 10.7554/elife.62576] [Citation(s) in RCA: 174] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
Making inferences about the computations performed by neuronal circuits from synapse-level connectivity maps is an emerging opportunity in neuroscience. The mushroom body (MB) is well positioned for developing and testing such an approach due to its conserved neuronal architecture, recently completed dense connectome, and extensive prior experimental studies of its roles in learning, memory, and activity regulation. Here, we identify new components of the MB circuit in Drosophila, including extensive visual input and MB output neurons (MBONs) with direct connections to descending neurons. We find unexpected structure in sensory inputs, in the transfer of information about different sensory modalities to MBONs, and in the modulation of that transfer by dopaminergic neurons (DANs). We provide insights into the circuitry used to integrate MB outputs, connectivity between the MB and the central complex and inputs to DANs, including feedback from MBONs. Our results provide a foundation for further theoretical and experimental work.
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Affiliation(s)
- Feng Li
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Jack W Lindsey
- Department of Neuroscience, Columbia University, Zuckerman InstituteNew YorkUnited States
| | - Elizabeth C Marin
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Nils Otto
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Centre for Neural Circuits & Behaviour, University of OxfordOxfordUnited Kingdom
| | - Marisa Dreher
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Georgia Dempsey
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Ildiko Stark
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Alexander S Bates
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | | | - Philipp Schlegel
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Shin-ya Takemura
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Nils Eckstein
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Tansy Yang
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Audrey Francis
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Amalia Braun
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Ruchi Parekh
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Marta Costa
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Louis K Scheffer
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Gregory SXE Jefferis
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Larry F Abbott
- Department of Neuroscience, Columbia University, Zuckerman InstituteNew YorkUnited States
| | - Ashok Litwin-Kumar
- Department of Neuroscience, Columbia University, Zuckerman InstituteNew YorkUnited States
| | - Scott Waddell
- Centre for Neural Circuits & Behaviour, University of OxfordOxfordUnited Kingdom
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
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39
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Beer K, Helfrich-Förster C. Model and Non-model Insects in Chronobiology. Front Behav Neurosci 2020; 14:601676. [PMID: 33328925 PMCID: PMC7732648 DOI: 10.3389/fnbeh.2020.601676] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/30/2020] [Indexed: 12/20/2022] Open
Abstract
The fruit fly Drosophila melanogaster is an established model organism in chronobiology, because genetic manipulation and breeding in the laboratory are easy. The circadian clock neuroanatomy in D. melanogaster is one of the best-known clock networks in insects and basic circadian behavior has been characterized in detail in this insect. Another model in chronobiology is the honey bee Apis mellifera, of which diurnal foraging behavior has been described already in the early twentieth century. A. mellifera hallmarks the research on the interplay between the clock and sociality and complex behaviors like sun compass navigation and time-place-learning. Nevertheless, there are aspects of clock structure and function, like for example the role of the clock in photoperiodism and diapause, which can be only insufficiently investigated in these two models. Unlike high-latitude flies such as Chymomyza costata or D. ezoana, cosmopolitan D. melanogaster flies do not display a photoperiodic diapause. Similarly, A. mellifera bees do not go into "real" diapause, but most solitary bee species exhibit an obligatory diapause. Furthermore, sociality evolved in different Hymenoptera independently, wherefore it might be misleading to study the social clock only in one social insect. Consequently, additional research on non-model insects is required to understand the circadian clock in Diptera and Hymenoptera. In this review, we introduce the two chronobiology model insects D. melanogaster and A. mellifera, compare them with other insects and show their advantages and limitations as general models for insect circadian clocks.
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Affiliation(s)
- Katharina Beer
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocentre, Am Hubland, University of Würzburg, Würzburg, Germany
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40
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Wang Q, Zhu D, Ping S, Li C, Pang K, Zhu S, Zhang J, Comai S, Sun J. Melatonin recovers sleep phase delayed by MK-801 through the melatonin MT 2 receptor- Ca 2+ -CaMKII-CREB pathway in the ventrolateral preoptic nucleus. J Pineal Res 2020; 69:e12674. [PMID: 32535982 DOI: 10.1111/jpi.12674] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 06/07/2020] [Accepted: 06/07/2020] [Indexed: 12/11/2022]
Abstract
Melatonin (MLT) is widely used to treat sleep disorders although the underlying mechanism is still elusive. In mice, using wheel-running detection, we found that exogenous MLT could completely recover the period length prolonged by N-methyl-D-aspartate receptor (NMDAR) impairment due to the injection of the NMDAR antagonist MK-801, a preclinical model of psychosis. The analysis of the possible underlying mechanisms indicated that MLT could regulate the homeostatic state in the ventrolateral preoptic nucleus (VLPO) instead of the circadian process in the suprachiasmatic nucleus (SCN). In addition, our data showed that MK-801 decreased Ca2+ -related CaMKII expression and CREB phosphorylation levels in the VLPO, and MLT could rescue these intracellular impairments but not NMDAR expression levels. Accordingly, Gcamp6 AAV virus was injected in-vivo to further monitor intracellular Ca2+ levels in the VLPO, and MLT demonstrated a unique ability to increase Ca2+ fluorescence compared with MK-801-injected mice. Additionally, using the selective melatonin MT2 receptor antagonist 4-phenyl-2-propionamidotetralin (4P-PDOT), we discovered that the pharmacological effects of MLT upon NMDAR impairments were mediated by melatonin MT2 receptors. Using electroencephalography/electromyography (EEG/EMG) recordings, we observed that the latency to the first nonrapid eye movement (NREM) sleep episode was delayed by MK-801, and MLT was able to recover this delay. In conclusion, exogenous MLT by acting upon melatonin MT2 receptors rescues sleep phase delayed by NMDAR impairment via increasing intracellular Ca2+ signaling in the VLPO, suggesting a regulatory role of the neurohormone on the homeostatic system.
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Affiliation(s)
- Qian Wang
- Department of Anatomy, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Dexiao Zhu
- Department of Anatomy, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Shuo Ping
- Department of Anatomy, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Chuangang Li
- Department of Anesthesiology, The Second Hospital of Shandong University, Jinan, China
| | - Kunkun Pang
- Department of Anatomy, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Shaowei Zhu
- Department of Anatomy, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Jing Zhang
- Department of Anatomy, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Stefano Comai
- Department of Psychiatry, McGill University, Montréal, QC, Canada
- San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | - Jinhao Sun
- Department of Anatomy, School of Basic Medical Sciences, Shandong University, Jinan, China
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41
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Rouyer F, Chatterjee A. Circadian Clocks: Structural Plasticity on the Input Side. Curr Biol 2020; 30:R890-R893. [PMID: 32750352 DOI: 10.1016/j.cub.2020.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Key Drosophila clock neurons remodel their axonal arborization on a daily basis. The current view is that remodelling is part of the control of clock neuron output but new data support a major role in modulating sensory inputs.
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Affiliation(s)
- François Rouyer
- Institut des Neurosciences Paris-Saclay, Université Paris-Sud, Université Paris-Saclay, CNRS, 91190 Gif-sur-Yvette, France.
| | - Abhishek Chatterjee
- Institut des Neurosciences Paris-Saclay, Université Paris-Sud, Université Paris-Saclay, CNRS, 91190 Gif-sur-Yvette, France
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42
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Ng R, Su CY. Neuroscience: Sensing Absolute Cold. Curr Biol 2020; 30:R809-R811. [PMID: 32693074 DOI: 10.1016/j.cub.2020.05.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To overwinter, animals must detect constant cold temperatures before adapting their behavior accordingly. A new study in Drosophila describes a circuit mechanism - from sensory neurons to higher brain centers - that encodes and relays persistent, absolute cold stimuli to modulate sleep.
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Affiliation(s)
- Renny Ng
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
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43
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Breda C, Rosato E, Kyriacou CP. Norpa Signalling and the Seasonal Circadian Locomotor Phenotype in Drosophila. BIOLOGY 2020; 9:biology9060130. [PMID: 32560221 PMCID: PMC7345481 DOI: 10.3390/biology9060130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/04/2020] [Accepted: 06/09/2020] [Indexed: 01/22/2023]
Abstract
In this paper, we review the role of the norpA-encoded phospholipase C in light and thermal entrainment of the circadian clock in Drosophila melanogaster. We extend our discussion to the role of norpA in the thermo-sensitive splicing of the per 3′ UTR, which has significant implications for seasonal adaptations of circadian behaviour. We use the norpA mutant-generated enhancement of per splicing and the corresponding advance that it produces in the morning (M) and evening (E) locomotor component to dissect out the neurons that are contributing to this norpA phenotype using GAL4/UAS. We initially confirmed, by immunocytochemistry and in situ hybridisation in adult brains, that norpA expression is mostly concentrated in the eyes, but we were unable to unequivocally reveal norpA expression in the canonical clock cells using these methods. In larval brains, we did see some evidence for co-expression of NORPA with PDF in clock neurons. Nevertheless, downregulation of norpA in clock neurons did generate behavioural advances in adults, with the eyes playing a significant role in the norpA seasonal phenotype at high temperatures, whereas the more dorsally located CRYPTOCHROME-positive clock neurons are the likely candidates for generating the norpA behavioural effects in the cold. We further show that knockdown of the related plc21C encoded phospholipase in clock neurons does not alter per splicing nor generate any of the behavioural advances seen with norpA. Our results with downregulating norpA and plc21C implicate the rhodopsins Rh2/Rh3/Rh4 in the eyes as mediating per 3′ UTR splicing at higher temperatures and indicate that the CRY-positive LNds, also known as ‘evening’ cells are likely mediating the low-temperature seasonal effects on behaviour via altering per 3′UTR splicing.
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44
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Abhilash L, Kalliyil A, Sheeba V. Responses of activity rhythms to temperature cues evolve in Drosophila populations selected for divergent timing of eclosion. ACTA ACUST UNITED AC 2020; 223:jeb.222414. [PMID: 32291322 DOI: 10.1242/jeb.222414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 04/02/2020] [Indexed: 12/28/2022]
Abstract
Even though the rhythms in adult emergence and locomotor activity are two different phenomena that occur at distinct life stages of the fly life cycle, previous studies have hinted at similarities in certain aspects of the organisation of the circadian clock driving these two rhythms. For instance, the period gene plays an important regulatory role in both rhythms. In an earlier study, we have shown that selection on timing of adult emergence behaviour in populations of Drosophila melanogaster leads to the co-evolution of temperature sensitivity of circadian clocks driving eclosion. In this study, we investigated whether temperature sensitivity of the locomotor activity rhythm evolved in our populations separately from the adult emergence rhythm, with the goal of understanding the extent of similarity (or lack thereof) in circadian organisation underlying the two rhythms. We found that in response to simulated jetlag with temperature cycles, late chronotypes (populations selected for predominant emergence during dusk) indeed re-entrained faster than early chronotypes (populations selected for predominant emergence during dawn) to 6 h phase delays, thereby indicating enhanced sensitivity of the activity/rest clock to temperature cues in these stocks (entrainment is the synchronisation of internal rhythms to cyclic environmental time cues). Additionally, we found that late chronotypes show higher plasticity of phases across regimes, day-to-day stability in phases and amplitude of entrainment, all indicative of enhanced temperature-sensitive activity/rest rhythms. Our results highlight remarkably similar organisation principles between circadian clocks regulating emergence and activity/rest rhythms.
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Affiliation(s)
- Lakshman Abhilash
- Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, Karnataka, India
| | - Arshad Kalliyil
- Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, Karnataka, India
| | - Vasu Sheeba
- Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, Karnataka, India
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45
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Alpert MH, Frank DD, Kaspi E, Flourakis M, Zaharieva EE, Allada R, Para A, Gallio M. A Circuit Encoding Absolute Cold Temperature in Drosophila. Curr Biol 2020; 30:2275-2288.e5. [PMID: 32442464 DOI: 10.1016/j.cub.2020.04.038] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/31/2020] [Accepted: 04/16/2020] [Indexed: 11/28/2022]
Abstract
Animals react to environmental changes over timescales ranging from seconds to days and weeks. An important question is how sensory stimuli are parsed into neural signals operating over such diverse temporal scales. Here, we uncover a specialized circuit, from sensory neurons to higher brain centers, that processes information about long-lasting, absolute cold temperature in Drosophila. We identify second-order thermosensory projection neurons (TPN-IIs) exhibiting sustained firing that scales with absolute temperature. Strikingly, this activity only appears below the species-specific, preferred temperature for D. melanogaster (∼25°C). We trace the inputs and outputs of TPN-IIs and find that they are embedded in a cold "thermometer" circuit that provides powerful and persistent inhibition to brain centers involved in regulating sleep and activity. Our results demonstrate that the fly nervous system selectively encodes and relays absolute temperature information and illustrate a sensory mechanism that allows animals to adapt behavior specifically to cold conditions on the timescale of hours to days.
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Affiliation(s)
- Michael H Alpert
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Dominic D Frank
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Evan Kaspi
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Matthieu Flourakis
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | | | - Ravi Allada
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Alessia Para
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Marco Gallio
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.
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46
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Fernandez MP, Pettibone HL, Bogart JT, Roell CJ, Davey CE, Pranevicius A, Huynh KV, Lennox SM, Kostadinov BS, Shafer OT. Sites of Circadian Clock Neuron Plasticity Mediate Sensory Integration and Entrainment. Curr Biol 2020; 30:2225-2237.e5. [PMID: 32386535 DOI: 10.1016/j.cub.2020.04.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 03/09/2020] [Accepted: 04/09/2020] [Indexed: 01/22/2023]
Abstract
Networks of circadian timekeeping in the brain display marked daily changes in neuronal morphology. In Drosophila melanogaster, the striking daily structural remodeling of the dorsal medial termini of the small ventral lateral neurons has long been hypothesized to mediate endogenous circadian timekeeping. To test this model, we have specifically abrogated these sites of daily neuronal remodeling through the reprogramming of neural development and assessed the effects on circadian timekeeping and clock outputs. Remarkably, the loss of these sites has no measurable effects on endogenous circadian timekeeping or on any of the major output functions of the small ventral lateral neurons. Rather, their loss reduces sites of glutamatergic sensory neurotransmission that normally encodes naturalistic time cues from the environment. These results support an alternative model: structural plasticity in critical clock neurons is the basis for proper integration of light and temperature and gates sensory inputs into circadian clock neuron networks.
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Affiliation(s)
- Maria P Fernandez
- Advanced Science Research Center, The Graduate Center, City University of New York, New York City, NY 10031, USA; Department of Neuroscience and Behavior, Barnard College of Columbia University, New York City, NY 10027, USA.
| | - Hannah L Pettibone
- Advanced Science Research Center, The Graduate Center, City University of New York, New York City, NY 10031, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Joseph T Bogart
- Advanced Science Research Center, The Graduate Center, City University of New York, New York City, NY 10031, USA
| | - Casey J Roell
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Charles E Davey
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ausra Pranevicius
- Department of Neuroscience and Behavior, Barnard College of Columbia University, New York City, NY 10027, USA
| | - Khang V Huynh
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sara M Lennox
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Boyan S Kostadinov
- Mathematics Department, NYC College of Technology, City University of New York, Brooklyn, NY 11201, USA
| | - Orie T Shafer
- Advanced Science Research Center, The Graduate Center, City University of New York, New York City, NY 10031, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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47
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Ding L, Xiao XH. Gut microbiota: closely tied to the regulation of circadian clock in the development of type 2 diabetes mellitus. Chin Med J (Engl) 2020; 133:817-825. [PMID: 32106122 PMCID: PMC7147650 DOI: 10.1097/cm9.0000000000000702] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Indexed: 12/20/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM), a worldwide epidemic disease, has caused tremendous economic and social burden, but the pathogenesis remains uncertain. Nowadays, the impact of unrhythmic circadian clock caused by irregular sleep and unhealthy diet on T2DM has be increasingly studied. However, the contribution of the endogenous circadian clock system to the development of T2DM has not yet been satisfactorily explored. It is now becoming clear that the gut microbiota and the circadian clock interact with each other to regulate the host metabolism. Considering all these above, we reviewed the literature related to the gut microbiota, circadian clock, and T2DM to elucidate the idea that the gut microbiota is closely tied to the regulation of the circadian clock in the development of T2DM, which provides potential for gut microbiota-directed therapies to ameliorate the effects of circadian disruptions linked to the occurrence and development of T2DM.
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Affiliation(s)
- Lu Ding
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Diabetes Research Center of Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
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48
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Damulewicz M, Mazzotta GM. One Actor, Multiple Roles: The Performances of Cryptochrome in Drosophila. Front Physiol 2020; 11:99. [PMID: 32194430 PMCID: PMC7066326 DOI: 10.3389/fphys.2020.00099] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/27/2020] [Indexed: 01/19/2023] Open
Abstract
Cryptochromes (CRYs) are flavoproteins that are sensitive to blue light, first identified in Arabidopsis and then in Drosophila and mice. They are evolutionarily conserved and play fundamental roles in the circadian clock of living organisms, enabling them to adapt to the daily 24-h cycles. The role of CRYs in circadian clocks differs among different species: in plants, they have a blue light-sensing activity whereas in mammals they act as light-independent transcriptional repressors within the circadian clock. These two different functions are accomplished by two principal types of CRYs, the light-sensitive plant/insect type 1 CRY and the mammalian type 2 CRY acting as a negative autoregulator in the molecular circadian clockwork. Drosophila melanogaster possesses just one CRY, belonging to type 1 CRYs. Nevertheless, this single CRY appears to have different functions, specific to different organs, tissues, and even subset of cells in which it is expressed. In this review, we will dissect the multiple roles of this single CRY in Drosophila, focusing on the regulatory mechanisms that make its pleiotropy possible.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Jagiellonian University, Kraków, Poland
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49
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Lamaze A, Stanewsky R. DN1p or the "Fluffy" Cerberus of Clock Outputs. Front Physiol 2020; 10:1540. [PMID: 31969832 PMCID: PMC6960142 DOI: 10.3389/fphys.2019.01540] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 12/05/2019] [Indexed: 12/12/2022] Open
Abstract
Drosophila melanogaster is a powerful genetic model to study the circadian clock. Recently, three drosophilists received the Nobel Prize for their intensive past and current work on the molecular clockwork (Nobel Prize 2017). The Drosophila brain clock is composed of about 150 clock neurons distributed along the lateral and dorsal regions of the protocerebrum. These clock neurons control the timing of locomotor behaviors. In standard light-dark (LD) conditions (12-12 h and constant 25°C), flies present a bi-modal locomotor activity pattern controlled by the clock. Flies increase their movement just before the light-transitions, and these behaviors are therefore defined as anticipatory. Two neuronal oscillators control the morning and evening anticipation. Knowing that the molecular clock cycles in phase in all clock neurons in the brain in LD, how can we explain the presence of two behavioral activity peaks separated by 12 h? According to one model, the molecular clock cycles in phase in all clock neurons, but the neuronal activity cycles with a distinct phase in the morning and evening oscillators. An alternative model takes the environmental condition into consideration. One group of clock neurons, the dorso-posterior clock neurons DN1p, drive two peaks of locomotor activity in LD even though their neuronal activity cycles with the same phase (late night/early morning). Interestingly, the locomotor outputs they control differ in their sensitivity to light and temperature. Hence, they must drive outputs to different neuropil regions in the brain, which also receive different inputs. Since 2010 and the presentation of the first specific DN1p manipulations, many studies have been performed to understand the role of this group of neurons in controlling locomotor behaviors. Hence, we review what we know about this heterogeneous group of clock neurons and discuss the second model to explain how clock neurons that oscillate with the same phase can drive behaviors at different times of the day.
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Affiliation(s)
- Angélique Lamaze
- Institut für Neuro und Verhaltensbiologie, Westfälische Wilhelms University, Münster, Germany
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King AN, Sehgal A. Molecular and circuit mechanisms mediating circadian clock output in the Drosophila brain. Eur J Neurosci 2020; 51:268-281. [PMID: 30059181 PMCID: PMC6353709 DOI: 10.1111/ejn.14092] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/12/2018] [Accepted: 07/23/2018] [Indexed: 01/06/2023]
Abstract
A central question in the circadian biology field concerns the mechanisms that translate ~24-hr oscillations of the molecular clock into overt rhythms. Drosophila melanogaster is a powerful system that provided the first understanding of how molecular clocks are generated and is now illuminating the neural basis of circadian behavior. The identity of ~150 clock neurons in the Drosophila brain and their roles in shaping circadian rhythms of locomotor activity have been described before. This review summarizes mechanisms that transmit time-of-day signals from the clock, within the clock network as well as downstream of it. We also discuss the identification of functional multisynaptic circuits between clock neurons and output neurons that regulate locomotor activity.
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Affiliation(s)
- Anna N. King
- Howard Hughes Medical Institute, Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Amita Sehgal
- Howard Hughes Medical Institute, Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
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