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Górska-Andrzejak J, Widacha L, Wadowski R, Mitka M, Tylko G. Dietary acrylamide disrupts the functioning of the biological clock. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:134912. [PMID: 38909469 DOI: 10.1016/j.jhazmat.2024.134912] [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: 02/05/2024] [Revised: 05/24/2024] [Accepted: 06/12/2024] [Indexed: 06/25/2024]
Abstract
Acrylamide (ACR) is a known carcinogen and neurotoxin. It is chronically consumed in carbohydrate-rich snacks processed at high temperatures. This calls for systematic research into the effects of ACR intake, best performed in an experimental model capable of detecting symptoms of its neurotoxicity at both high and low doses. Here, we study the influence of 10 µg/g (corresponding to the concentrations found in food products) and, for comparison, 60, 80 and 110 µg/g dietary ACR, on the fruit fly Drosophila melanogaster. We show that chronic administration of ACR affects lifespan, activity level and, most importantly, the daily and circadian pattern of locomotor activity of Drosophila. ACR-treated flies show well-defined and concentration-dependent symptoms of ACR neurotoxicity; a reduced anticipation of upcoming changes in light conditions and increased arrhythmicity in constant darkness. The results suggest that the rhythm-generating neural circuits of their circadian oscillator (biological clock) are sensitive to ACR even at low concentrations if the exposure time is sufficiently long. This makes the behavioural readout of the clock, the rhythm of locomotor activity, a useful tool for studying the adverse effects of ACR and probably other compounds.
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Affiliation(s)
- Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland.
| | - Lucyna Widacha
- Chair of Exercise Physiology and Muscle Bioenergetics, Faculty of Health Sciences, Jagiellonian University Medical College, Kraków, Poland
| | - Robert Wadowski
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Monika Mitka
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Grzegorz Tylko
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
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2
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Jay TR, Kang Y, Ouellet-Massicotte V, Micael MKB, Kacouros-Perkins VL, Chen J, Sheehan A, Freeman MR. Developmental and age-related synapse elimination is mediated by glial Croquemort. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.24.600214. [PMID: 39026803 PMCID: PMC11257470 DOI: 10.1101/2024.06.24.600214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Neurons and glia work together to dynamically regulate neural circuit assembly and maintenance. In this study, we show Drosophila exhibit large-scale synapse formation and elimination as part of normal CNS circuit maturation, and that glia use conserved molecules to regulate these processes. Using a high throughput ELISA-based in vivo screening assay, we identify new glial genes that regulate synapse numbers in Drosophila in vivo, including the scavenger receptor ortholog Croquemort (Crq). Crq acts as an essential regulator of glial-dependent synapse elimination during development, with glial Crq loss leading to excess CNS synapses and progressive seizure susceptibility in adults. Loss of Crq in glia also prevents age-related synaptic loss in the adult brain. This work provides new insights into the cellular and molecular mechanisms that underlie synapse development and maintenance across the lifespan, and identifies glial Crq as a key regulator of these processes.
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3
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Hofbauer B, Zandawala M, Reinhard N, Rieger D, Werner C, Evers JF, Wegener C. The neuropeptide pigment-dispersing factor signals independently of Bruchpilot-labelled active zones in daily remodelled terminals of Drosophila clock neurons. Eur J Neurosci 2024; 59:2665-2685. [PMID: 38414155 DOI: 10.1111/ejn.16294] [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: 06/21/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 02/29/2024]
Abstract
The small ventrolateral neurons (sLNvs) are key components of the central clock in the Drosophila brain. They signal via the neuropeptide pigment-dispersing factor (PDF) to align the molecular clockwork of different central clock neurons and to modulate downstream circuits. The dorsal terminals of the sLNvs undergo daily morphological changes that affect presynaptic sites organised by the active zone protein Bruchpilot (BRP), a homolog of mammalian ELKS proteins. However, the role of these presynaptic sites for PDF release is ill-defined. Here, we combined expansion microscopy with labelling of active zones by endogenously tagged BRP to examine the spatial correlation between PDF-containing dense-core vesicles and BRP-labelled active zones. We found that the number of BRP-labelled puncta in the sLNv terminals was similar while their density differed between Zeitgeber time (ZT) 2 and 14. The relative distance between BRP- and PDF-labelled puncta was increased in the morning, around the reported time of PDF release. Spontaneous dense-core vesicle release profiles of sLNvs in a publicly available ssTEM dataset (FAFB) consistently lacked spatial correlation to BRP-organised active zones. RNAi-mediated downregulation of brp and other active zone proteins expressed by the sLNvs did not affect PDF-dependent locomotor rhythmicity. In contrast, down-regulation of genes encoding proteins of the canonical vesicle release machinery, the dense-core vesicle-related protein CADPS, as well as PDF impaired locomotor rhythmicity. Taken together, our study suggests that PDF release from the sLNvs is independent of BRP-organised active zones, while BRP may be redistributed to active zones in a time-dependent manner.
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Affiliation(s)
- Benedikt Hofbauer
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Meet Zandawala
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
- Department of Biochemistry and Molecular Biology, University of Nevada Reno, Reno, NV, USA
| | - Nils Reinhard
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Dirk Rieger
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Christian Werner
- Biocenter, Theodor-Boveri-Institute, Department of Biotechnology and Biophysics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Jan Felix Evers
- Centre for organismal studies COS, Universität Heidelberg, Heidelberg, Germany
- Cairn GmbH, Heidelberg, Germany
| | - Christian Wegener
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
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4
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Anna G, John M, Kannan NN. miR-277 regulates the phase of circadian activity-rest rhythm in Drosophila melanogaster. Front Physiol 2023; 14:1082866. [PMID: 38089472 PMCID: PMC10714010 DOI: 10.3389/fphys.2023.1082866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/07/2023] [Indexed: 12/30/2023] Open
Abstract
Circadian clocks temporally organize behaviour and physiology of organisms with a rhythmicity of about 24 h. In Drosophila, the circadian clock is composed of mainly four clock genes: period (per), timeless (tim), Clock (Clk) and cycle (cyc) which constitutes the transcription-translation feedback loop. The circadian clock is further regulated via post-transcriptional and post-translational mechanisms among which microRNAs (miRNAs) are well known post-transcriptional regulatory molecules. Here, we identified and characterized the role of miRNA-277 (miR-277) expressed in the clock neurons in regulating the circadian rhythm. Downregulation of miR-277 in the pacemaker neurons expressing circadian neuropeptide, pigment dispersing factor (PDF) advanced the phase of the morning activity peak under 12 h light: 12 h dark cycles (LD) at lower light intensities and these flies exhibited less robust rhythms compared to the controls under constant darkness. In addition, downregulation of miR-277 in the PDF expressing neurons abolished the Clk gene transcript oscillation under LD. Our study points to the potential role of miR-277 in fine tuning the Clk expression and in maintaining the phase of the circadian rhythm in Drosophila.
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Affiliation(s)
| | | | - Nisha N. Kannan
- Chronobiology Laboratory, School of Biology, Indian Institute of Science Education and Research (IISER), Thiruvananthapuram, Kerala, India
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Bhattacharya D, Górska-Andrzejak J, Abaquita TAL, Pyza E. Effects of adenosine receptor overexpression and silencing in neurons and glial cells on lifespan, fitness, and sleep of Drosophila melanogaster. Exp Brain Res 2023:10.1007/s00221-023-06649-y. [PMID: 37335362 DOI: 10.1007/s00221-023-06649-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 05/28/2023] [Indexed: 06/21/2023]
Abstract
A single adenosine receptor gene (dAdoR) has been detected in Drosophila melanogaster. However, its function in different cell types of the nervous system is mostly unknown. Therefore, we overexpressed or silenced the dAdoR gene in eye photoreceptors, all neurons, or glial cells and examined the fitness of flies, the amount and daily pattern of sleep, and the influence of dAdoR silencing on Bruchpilot (BRP) presynaptic protein. Furthermore, we examined the dAdoR and brp gene expression in young and old flies. We found that a higher level of dAdoR in the retina photoreceptors, all neurons, and glial cells negatively influenced the survival rate and lifespan of male and female Drosophila in a cell-dependent manner and to a different extent depending on the age of the flies. In old flies, expression of both dAdoR and brp was higher than in young ones. An excess of dAdoR in neurons improved climbing in older individuals. It also influenced sleep by lengthening nighttime sleep and siesta. In turn, silencing of dAdoR decreased the lifespan of flies, although it increased the survival rate of young flies. It hindered the climbing of older males and females, but did not change sleep. Silencing also affected the daily pattern of BRP abundance, especially when dAdoR expression was decreased in glial cells. The obtained results indicate the role of adenosine and dAdoR in the regulation of fitness in flies that is based on communication between neurons and glial cells, and the effect of glial cells on synapses.
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Affiliation(s)
| | | | | | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Jagellonian University, Kraków, Poland.
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Jarabo P, de Pablo C, González-Blanco A, Casas-Tintó S. Circadian Gene cry Controls Tumorigenesis through Modulation of Myc Accumulation in Glioblastoma Cells. Int J Mol Sci 2022; 23:ijms23042043. [PMID: 35216153 PMCID: PMC8874709 DOI: 10.3390/ijms23042043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/04/2022] [Accepted: 02/08/2022] [Indexed: 12/04/2022] Open
Abstract
Glioblastoma (GB) is the most frequent malignant brain tumor among adults and currently there is no effective treatment. This aggressive tumor grows fast and spreads through the brain causing death in 15 months. GB cells display a high mutation rate and generate a heterogeneous population of tumoral cells that are genetically distinct. Thus, the contribution of genes and signaling pathways relevant for GB progression is of great relevance. We used a Drosophila model of GB that reproduces the features of human GB and describe the upregulation of the circadian gene cry in GB patients and in a Drosophila GB model. We studied the contribution of cry to the expansion of GB cells and the neurodegeneration and premature death caused by GB, and we determined that cry is required for GB progression. Moreover, we determined that the PI3K pathway regulates cry expression in GB cells, and in turn, cry is necessary and sufficient to promote Myc accumulation in GB. These results contribute to understanding the mechanisms underlying GB malignancy and lethality, and describe a novel role of Cry in GB cells.
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Yildirim E, Curtis R, Hwangbo DS. Roles of peripheral clocks: lessons from the fly. FEBS Lett 2022; 596:263-293. [PMID: 34862983 PMCID: PMC8844272 DOI: 10.1002/1873-3468.14251] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 02/03/2023]
Abstract
To adapt to and anticipate rhythmic changes in the environment such as daily light-dark and temperature cycles, internal timekeeping mechanisms called biological clocks evolved in a diverse set of organisms, from unicellular bacteria to humans. These biological clocks play critical roles in organisms' fitness and survival by temporally aligning physiological and behavioral processes to the external cues. The central clock is located in a small subset of neurons in the brain and drives daily activity rhythms, whereas most peripheral tissues harbor their own clock systems, which generate metabolic and physiological rhythms. Since the discovery of Drosophila melanogaster clock mutants in the early 1970s, the fruit fly has become an extensively studied model organism to investigate the mechanism and functions of circadian clocks. In this review, we primarily focus on D. melanogaster to survey key discoveries and progresses made over the past two decades in our understanding of peripheral clocks. We discuss physiological roles and molecular mechanisms of peripheral clocks in several different peripheral tissues of the fly.
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Affiliation(s)
| | - Rachel Curtis
- Department of Biology, University of Louisville, Louisville, KY, USA
| | - Dae-Sung Hwangbo
- Department of Biology, University of Louisville, Louisville, KY, USA
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8
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Gregor KM, Becker SC, Hellhammer F, Baumgärtner W, Puff C. Immunohistochemical Characterization of the Nervous System of Culex pipiens (Diptera, Culicidae). BIOLOGY 2022; 11:57. [PMID: 35053056 PMCID: PMC8772823 DOI: 10.3390/biology11010057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 11/24/2022]
Abstract
Arthropod-borne diseases represent one of the greatest infection-related threats as a result of climate change and globalization. Repeatedly, arbovirus-infected mosquitoes show behavioral changes whose underlying mechanisms are still largely unknown, but might help to develop control strategies. However, in contrast to well-characterized insects such as fruit flies, little is known about neuroanatomy and neurotransmission in mosquitoes. To overcome this limitation, the study focuses on the immunohistochemical characterization of the nervous system of Culex pipiens biotype molestus in comparison to Drosophila melanogaster using 13 antibodies labeling nervous tissue, neurotransmitters or neurotransmitter-related enzymes. Antibodies directed against γ-aminobutyric acid, serotonin, tyrosine-hydroxylase and glutamine synthetase were suitable for investigations in Culex pipiens and Drosophila melanogaster, albeit species-specific spatial differences were observed. Likewise, similar staining results were achieved for neuronal glycoproteins, axons, dendrites and synaptic zones in both species. Interestingly, anti-phosphosynapsin and anti-gephyrin appear to represent novel markers for synapses and glial cells, respectively. In contrast, antibodies directed against acetylcholine, choline acetyltransferase, elav and repo failed to produce a signal in Culex pipiens comparable to that in Drosophila melanogaster. In summary, present results enable a detailed investigation of the nervous system of mosquitoes, facilitating further studies of behavioral mechanisms associated with arboviruses in the course of vector research.
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Affiliation(s)
- Katharina M. Gregor
- Department of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, Lower Saxony, 30559 Hannover, Germany; (K.M.G.); (C.P.)
| | - Stefanie C. Becker
- Institute for Parasitology, University of Veterinary Medicine Hannover, Bünteweg 17, Lower Saxony, 30559 Hannover, Germany; (S.C.B.); (F.H.)
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Bünteweg 17, Lower Saxony, 30559 Hannover, Germany
| | - Fanny Hellhammer
- Institute for Parasitology, University of Veterinary Medicine Hannover, Bünteweg 17, Lower Saxony, 30559 Hannover, Germany; (S.C.B.); (F.H.)
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Bünteweg 17, Lower Saxony, 30559 Hannover, Germany
| | - Wolfgang Baumgärtner
- Department of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, Lower Saxony, 30559 Hannover, Germany; (K.M.G.); (C.P.)
| | - Christina Puff
- Department of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, Lower Saxony, 30559 Hannover, Germany; (K.M.G.); (C.P.)
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9
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Walkowicz L, Krzeptowski W, Krzeptowska E, Warzecha K, Sałek J, Górska-Andrzejak J, Pyza E. Glial expression of DmMANF is required for the regulation of activity, sleep and circadian rhythms in the visual system of Drosophila melanogaster. Eur J Neurosci 2021; 54:5785-5797. [PMID: 33666288 DOI: 10.1111/ejn.15171] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 01/31/2021] [Accepted: 02/22/2021] [Indexed: 12/12/2022]
Abstract
DmMANF, Drosophila melanogaster mesencephalic astrocyte-derived neurotrophic factor (DmMANF) is an evolutionarily conserved orthologue of mammalian MANF. This neurotrophic factor exerts many functions in the Drosophila brain, particularly those dependent on glial cells. As we found in our earlier study, downregulation of DmMANF in glia induces degeneration of glial cells in the first optic neuropil (lamina) where DmMANF abundance is especially high. In the present study, we observed that changes in the level of DmMANF in two types of glia, astrocyte-like glia (AlGl) and ensheathing glia (EnGl), affect activity and sleep of flies. Interestingly, a proper level of DmMANF in AlGl seems to be important in guiding processes of pigment dispersing factor (PDF)-expressing clock neurons. This is supported by our finding that DmMANF overexpression in AlGl leads to structural changes in the architecture of the PDF-positive arborization in the brain. Finally, we detected that DmMANF also affects rhythms in glia themselves, as circadian oscillations in expression of the catalytic α subunit of the sodium pump in the lamina epithelial glia were abolished after DmMANF silencing. DmMANF expressed in AlGl and EnGl seems to affect the activity of neurons leading to changes in behaviour.
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Affiliation(s)
- Lucyna Walkowicz
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Wojciech Krzeptowski
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Ewelina Krzeptowska
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Karolina Warzecha
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Joanna Sałek
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
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10
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The expression of circadian clock genes in Daphnia magna diapause. Sci Rep 2020; 10:19928. [PMID: 33199823 PMCID: PMC7669902 DOI: 10.1038/s41598-020-77065-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/30/2020] [Indexed: 11/17/2022] Open
Abstract
Diapause is a mechanism necessary for survival in arthropods. Often diapause induction and resurrection is light-dependent and therefore dependent on the photoperiod length and on the number of consecutive short-days. In many organisms, including the microcrustacean Daphnia magna, one functional entity with the capacity to measure seasonal changes in day-length is the circadian clock. There is a long-standing discussion that the circadian clock also controls photoperiod-induced diapause. We tested this hypothesis in D. magna, an organism which goes into a state of suspended animation with the shortening of the photoperiod. We measured gene expression of clock genes in diapause-destined embryos of D. magna in the initiation, resting and resurrection phases and checked it against gene expression levels of continuously developing embryos. We demonstrate that some genes of the clock are differentially expressed during diapause induction but not during its maintenance. Furthermore, the photoreceptor gene cry2 and the clock-associated gene brp are highly expressed during induction and early diapause, probably in order to produce excess mRNA to prepare for immediate resurrection. After resurrection, both types of embryos show a similar pattern of gene expression during development. Our study contributes significantly to the understanding of the molecular basis of diapause induction, maintenance and termination.
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11
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Jasinska M, Woznicka O, Jasek-Gajda E, Lis GJ, Pyza E, Litwin JA. Circadian Changes of Dendritic Spine Geometry in Mouse Barrel Cortex. Front Neurosci 2020; 14:578881. [PMID: 33117123 PMCID: PMC7550732 DOI: 10.3389/fnins.2020.578881] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/26/2020] [Indexed: 11/13/2022] Open
Abstract
The circadian rhythmicity changes the density and shape of dendritic spines in mouse somatosensory barrel cortex, influencing their stability and maturation. In this study, we analyzed the main geometric parameters of dendritic spines reflecting the strength of synapses located on these spines under light/dark (12:12) and constant darkness conditions, in order to distinguish between endogenously regulated and light-driven parameters. Using morphological analysis of serial electron micrographs, as well as three-dimensional reconstructions, we found that the light induces elongation of single-synapse spine necks and increases in the diameter of double-synapse spine necks, increasing and decreasing the isolation of synapses from the parent dendrite, respectively. During the subjective night of constant darkness, we observed an enlargement of postsynaptic density area in inhibitory synapses and an increase in the number of polyribosomes inside double-synapse spines. The results show that both endogenous effect (circadian clock/locomotor activity) and light affect the morphological parameters of single- and double-synapse spines in the somatosensory cortex: light reduces the efficiency of excitatory synapses on single-synapse spines, increases the effect of synaptic transmission in double-synapse spines, and additionally masks the endogenous clock-driven enlargement of inhibitory synapses located on double-synapse spines. This indicates a special role of double-synapse spines and their inhibitory synapses in the regulation of synaptic transmission during both circadian and diurnal cycles in the mouse somatosensory cortex.
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Affiliation(s)
- Malgorzata Jasinska
- Department of Histology, Jagiellonian University Medical College, Krakow, Poland
| | - Olga Woznicka
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Ewa Jasek-Gajda
- Department of Histology, Jagiellonian University Medical College, Krakow, Poland
| | - Grzegorz J Lis
- Department of Histology, Jagiellonian University Medical College, Krakow, Poland
| | - Elzbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Jan A Litwin
- Department of Histology, Jagiellonian University Medical College, Krakow, Poland
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12
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Damulewicz M, Woźnicka O, Jasińska M, Pyza E. CRY-dependent plasticity of tetrad presynaptic sites in the visual system of Drosophila at the morning peak of activity and sleep. Sci Rep 2020; 10:18161. [PMID: 33097794 PMCID: PMC7585400 DOI: 10.1038/s41598-020-74442-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 09/22/2020] [Indexed: 11/09/2022] Open
Abstract
Tetrad synapses are formed between the retina photoreceptor terminals and postsynaptic cells in the first optic neuropil (lamina) of Drosophila. They are remodelled in the course of the day and show distinct functional changes during activity and sleep. These changes result from fast degradation of the presynaptic scaffolding protein Bruchpilot (BRP) by Cryptochrome (CRY) in the morning and depend on BRP-170, one of two BRP isoforms. This process also affects the number of synaptic vesicles, both clear and dense-core, delivered to the presynaptic elements. In cry01 mutants lacking CRY and in brpΔ170, the number of synaptic vesicles is lower in the morning peak of activity than during night-sleep while in wild-type flies the number of synaptic vesicles is similar at these two time points. CRY may also set phase of the circadian rhythm in plasticity of synapses. The process of synapse remodelling stimulates the formation of clear synaptic vesicles in the morning. They carry histamine, a neurotransmitter in tetrad synapses and seem to be formed from glial capitate projections inside the photoreceptor terminals. In turn dense-core vesicles probably carry synaptic proteins building the tetrad presynaptic element.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Olga Woźnicka
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Małgorzata Jasińska
- Department of Histology, Jagiellonian University Medical College, Kraków, Poland
| | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland.
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13
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Duhart JM, Herrero A, de la Cruz G, Ispizua JI, Pírez N, Ceriani MF. Circadian Structural Plasticity Drives Remodeling of E Cell Output. Curr Biol 2020; 30:5040-5048.e5. [PMID: 33065014 DOI: 10.1016/j.cub.2020.09.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/21/2020] [Accepted: 09/17/2020] [Indexed: 12/15/2022]
Abstract
Behavioral outputs arise as a result of highly regulated yet flexible communication among neurons. The Drosophila circadian network includes 150 neurons that dictate the temporal organization of locomotor activity; under light-dark (LD) conditions, flies display a robust bimodal pattern. The pigment-dispersing factor (PDF)-positive small ventral lateral neurons (sLNv) have been linked to the generation of the morning activity peak (the "M cells"), whereas the Cryptochrome (CRY)-positive dorsal lateral neurons (LNds) and the PDF-negative sLNv are necessary for the evening activity peak (the "E cells") [1, 2]. While each group directly controls locomotor output pathways [3], an interplay between them along with a third dorsal cluster (the DN1ps) is necessary for the correct timing of each peak and for adjusting behavior to changes in the environment [4-7]. M cells set the phase of roughly half of the circadian neurons (including the E cells) through PDF [5, 8-10]. Here, we show the existence of synaptic input provided by the evening oscillator onto the M cells. Both structural and functional approaches revealed that E-to-M cell connectivity changes across the day, with higher excitatory input taking place before the day-to-night transition. We identified two different neurotransmitters, acetylcholine and glutamate, released by E cells that are relevant for robust circadian output. Indeed, we show that acetylcholine is responsible for the excitatory input from E cells to M cells, which show preferential responsiveness to acetylcholine during the evening. Our findings provide evidence of an excitatory feedback between circadian clusters and unveil an important plastic remodeling of the E cells' synaptic connections.
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Affiliation(s)
- José M Duhart
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - Anastasia Herrero
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - Gabriel de la Cruz
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - Juan I Ispizua
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - Nicolás Pírez
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - M Fernanda Ceriani
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina.
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14
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Damulewicz M, Ispizua JI, Ceriani MF, Pyza EM. Communication Among Photoreceptors and the Central Clock Affects Sleep Profile. Front Physiol 2020; 11:993. [PMID: 32848895 PMCID: PMC7431659 DOI: 10.3389/fphys.2020.00993] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/22/2020] [Indexed: 12/17/2022] Open
Abstract
Light is one of the most important factors regulating rhythmical behavior of Drosophila melanogaster. It is received by different photoreceptors and entrains the circadian clock, which controls sleep. The retina is known to be essential for light perception, as it is composed of specialized light-sensitive cells which transmit signal to deeper parts of the brain. In this study we examined the role of specific photoreceptor types and peripheral oscillators located in these cells in the regulation of sleep pattern. We showed that sleep is controlled by the visual system in a very complex way. Photoreceptors expressing Rh1, Rh3 are involved in night-time sleep regulation, while cells expressing Rh5 and Rh6 affect sleep both during the day and night. Moreover, Hofbauer-Buchner (HB) eyelets which can directly contact with s-LN v s and l-LN v s play a wake-promoting function during the day. In addition, we showed that L2 interneurons, which receive signal from R1-6, form direct synaptic contacts with l-LN v s, which provides new light input to the clock network.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Jagiellonian University, Kraków, Poland
| | - Juan I. Ispizua
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Maria F. Ceriani
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Elzbieta M. Pyza
- Department of Cell Biology and Imaging, Jagiellonian University, Kraków, Poland
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15
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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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16
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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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17
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Czypionka T, Fields PD, Routtu J, van den Berg E, Ebert D, De Meester L. The genetic architecture underlying diapause termination in a planktonic crustacean. Mol Ecol 2019; 28:998-1008. [PMID: 30592346 DOI: 10.1111/mec.15001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 11/15/2018] [Accepted: 11/27/2018] [Indexed: 01/17/2023]
Abstract
Diapause is a feature of the life cycle of many invertebrates by which unfavourable environmental conditions can be outlived. The seasonal timing of diapause allows organisms to adapt to seasonal changes in habitat suitability and thus is key to their fitness. In the planktonic crustacean Daphnia, various cues can induce the production of diapause stages that are resistant to heat, drought or freezing and contain one to two embryos in developmental arrest. Daphnia is a keystone species of many freshwater ecosystems, where it acts as the main link between phytoplankton and higher trophic levels. The correct seasonal timing of diapause termination is essential to maintain trophic interactions and is achieved via a genetically based interpretation of environmental cues like photoperiod and temperature. Field monitoring and modelling studies raised concerns on whether populations can advance their seasonal release from diapause to advances in spring phenology under global change, or if a failure to adapt will cause trophic mismatches negatively affecting ecosystem functioning. Our capacity to understand and predict the evolution of diapause timing requires information about the genetic architecture underlying this trait. In this study, we identified eight quantitative trait loci (QTLs) and four epistatic interactions that together explained 66.5% of the variation in diapause termination in Daphnia magna using QTL mapping. Our results suggest that the most significant QTL is modulating diapause termination dependent on photoperiod and is involved in three of the four detected epistatic interactions. Candidate genes at this QTL could be identified through the integration with genome data and included the presynaptic active zone protein bruchpilot. Our findings contribute to understanding the genomic control of seasonal diapause timing in an ecological relevant species.
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Affiliation(s)
- Till Czypionka
- Laboratory of Aquatic Ecology and Evolutionary Biology, KU Leuven, Leuven, Belgium
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Jarkko Routtu
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland.,Molecular Ecology, Martin-Luther-Universität, Halle-Wittenberg, Germany
| | - Edwin van den Berg
- Laboratory of Aquatic Ecology and Evolutionary Biology, KU Leuven, Leuven, Belgium
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Luc De Meester
- Laboratory of Aquatic Ecology and Evolutionary Biology, KU Leuven, Leuven, Belgium
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18
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Daily Regulation of Phototransduction, Circadian Clock, DNA Repair, and Immune Gene Expression by Heme Oxygenase in the Retina of Drosophila. Genes (Basel) 2018; 10:genes10010006. [PMID: 30583479 PMCID: PMC6357063 DOI: 10.3390/genes10010006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/03/2018] [Accepted: 12/17/2018] [Indexed: 01/13/2023] Open
Abstract
The daily expression of genes and the changes in gene expression after silencing the heme oxygenase (ho) gene were examined in the retina of Drosophila using microarray and SybrGreen qPCR (quantitative polymerase chain reaction) methods. The HO decrease in the morning upregulated 83 genes and downregulated 57 genes. At night, 80 genes were upregulated and 22 were downregulated. The top 20 genes downregulated after ho silencing in the morning modulate phototransduction, immune responses, autophagy, phagocytosis, apoptosis, the carbon monoxide (CO) response, the oxidative stress/UV response, and translation. In turn, the genes that upregulated at night were involved in translation—the response to oxidative stress, DNA damage, and phototransduction. Among the top 20 genes downregulated at night were genes involved in phototransduction, immune responses, and autophagy. For some genes, a low level of HO had an opposite effect in the morning compared to those at night. Silencing ho also changed the expression of circadian clock genes, while the HO decrease during the night enhanced the expression of immune system genes. The results showed that the cyclic expression of HO is important for controlling several processes in the retina, including neuroprotection and those involved in the innate immune system.
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19
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Mansilla A, Jordán-Álvarez S, Santana E, Jarabo P, Casas-Tintó S, Ferrús A. Molecular mechanisms that change synapse number. J Neurogenet 2018; 32:155-170. [DOI: 10.1080/01677063.2018.1506781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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20
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Krzeptowski W, Hess G, Pyza E. Circadian Plasticity in the Brain of Insects and Rodents. Front Neural Circuits 2018; 12:32. [PMID: 29770112 PMCID: PMC5942159 DOI: 10.3389/fncir.2018.00032] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/09/2018] [Indexed: 12/22/2022] Open
Abstract
In both vertebrate and invertebrate brains, neurons, glial cells and synapses are plastic, which means that the physiology and structure of these components are modified in response to internal and external stimuli during development and in mature brains. The term plasticity has been introduced in the last century to describe experience-dependent changes in synapse strength and number. These changes result from local functional and morphological synapse modifications; however, these modifications also occur more commonly in pre- and postsynaptic neurons. As a result, neuron morphology and neuronal networks are constantly modified during the life of animals and humans in response to different stimuli. Nevertheless, it has been discovered in flies and mammals that the number of synapses and size and shape of neurons also oscillate during the day. In most cases, these rhythms are circadian since they are generated by endogenous circadian clocks; however, some rhythmic changes in neuron morphology and synapse number and structure are controlled directly by environmental cues or by both external cues and circadian clocks. When the circadian clock is involved in generating cyclic changes in the nervous system, this type of plasticity is called circadian plasticity. It seems to be important in processing sensory information, in learning and in memory. Disruption of the clock may affect major brain functions.
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Affiliation(s)
- Wojciech Krzeptowski
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Grzegorz Hess
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland.,Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
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21
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Krzeptowski W, Walkowicz L, Płonczyńska A, Górska-Andrzejak J. Different Levels of Expression of the Clock Protein PER and the Glial Marker REPO in Ensheathing and Astrocyte-Like Glia of the Distal Medulla of Drosophila Optic Lobe. Front Physiol 2018; 9:361. [PMID: 29695973 PMCID: PMC5904279 DOI: 10.3389/fphys.2018.00361] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/23/2018] [Indexed: 12/31/2022] Open
Abstract
Circadian plasticity of the visual system of Drosophila melanogaster depends on functioning of both the neuronal and glial oscillators. The clock function of the former is already quite well-recognized. The latter, however, is much less known and documented. In this study we focus on the glial oscillators that reside in the distal part of the second visual neuropil, medulla (dMnGl), in vicinity of the PIGMENT-DISPERSING FACTOR (PDF) releasing terminals of the circadian clock ventral Lateral Neurons (LNvs). We reveal the heterogeneity of the dMnGl, which express the clock protein PERIOD (PER) and the pan-glial marker REVERSED POLARITY (REPO) at higher (P1) or lower (P2) levels. We show that the cells with stronger expression of PER display also stronger expression of REPO, and that the number of REPO-P1 cells is bigger during the day than during the night. Using a combination of genetic markers and immunofluorescent labeling with anti PER and REPO Abs, we have established that the P1 and P2 cells can be associated with two different types of the dMnGl, the ensheathing (EnGl), and the astrocyte-like glia (ALGl). Surprisingly, the EnGl belong to the P1 cells, whereas the ALGl, previously reported to play the main role in the circadian rhythms, display the characteristics of the P2 cells (express very low level of PER and low level of REPO). Next to the EnGl and ALGl we have also observed another type of cells in the distal medulla that express PER and REPO, although at very low levels. Based on their morphology we have identified them as the T1 interneurons. Our study reveals the complexity of the distal medulla circadian network, which appears to consist of different types of glial and neuronal peripheral clocks, displaying molecular oscillations of higher (EnGl) and lower (ALGl and T1) amplitudes.
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Affiliation(s)
- Wojciech Krzeptowski
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Lucyna Walkowicz
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Alicja Płonczyńska
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
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22
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Górska-Andrzejak J, Chwastek EM, Walkowicz L, Witek K. On Variations in the Level of PER in Glial Clocks of Drosophila Optic Lobe and Its Negative Regulation by PDF Signaling. Front Physiol 2018; 9:230. [PMID: 29615925 PMCID: PMC5868474 DOI: 10.3389/fphys.2018.00230] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/01/2018] [Indexed: 02/05/2023] Open
Abstract
We show that the level of the core protein of the circadian clock Period (PER) expressed by glial peripheral oscillators depends on their location in the Drosophila optic lobe. It appears to be controlled by the ventral lateral neurons (LNvs) that release the circadian neurotransmitter Pigment Dispersing Factor (PDF). We demonstrate that glial cells of the distal medulla neuropil (dMnGl) that lie in the vicinity of the PDF-releasing terminals of the LNvs possess receptors for PDF (PDFRs) and express PER at significantly higher level than other types of glia. Surprisingly, the amplitude of PER molecular oscillations in dMnGl is increased twofold in PDF-free environment, that is in Pdf0 mutants. The Pdf0 mutants also reveal an increased level of glia-specific protein REPO in dMnGl. The photoreceptors of the compound eye (R-cells) of the PDF-null flies, on the other hand, exhibit de-synchrony of PER molecular oscillations, which manifests itself as increased variability of PER-specific immunofluorescence among the R-cells. Moreover, the daily pattern of expression of the presynaptic protein Bruchpilot (BRP) in the lamina terminals of the R-cells is changed in Pdf0 mutant. Considering that PDFRs are also expressed by the marginal glia of the lamina that surround the R-cell terminals, the LNv pacemakers appear to be the likely modulators of molecular cycling in the peripheral clocks of both the glial cells and the photoreceptors of the compound eye. Consequently, some form of PDF-based coupling of the glial clocks and the photoreceptors of the eye with the central LNv pacemakers must be operational.
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Affiliation(s)
- Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Elżbieta M Chwastek
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Lucyna Walkowicz
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Kacper Witek
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
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23
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Ehmann N, Owald D, Kittel RJ. Drosophila active zones: From molecules to behaviour. Neurosci Res 2018; 127:14-24. [DOI: 10.1016/j.neures.2017.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 11/30/2017] [Accepted: 11/30/2017] [Indexed: 11/15/2022]
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24
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Doktór B, Damulewicz M, Krzeptowski W, Bednarczyk B, Pyza E. Effects of PINK1 mutation on synapses and behavior in the brain of Drosophila melanogaster. Acta Neurobiol Exp (Wars) 2018. [DOI: 10.21307/ane-2018-021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Nippe OM, Wade AR, Elliott CJH, Chawla S. Circadian Rhythms in Visual Responsiveness in the Behaviorally Arrhythmic Drosophila Clock Mutant Clk Jrk. J Biol Rhythms 2017; 32:583-592. [PMID: 29172879 PMCID: PMC5734378 DOI: 10.1177/0748730417735397] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
An organism's biological day is characterized by a pattern of anticipatory physiological and behavioral changes that are governed by circadian clocks to align with the 24-h cycling environment. Here, we used flash electroretinograms (ERGs) and steady-state visually evoked potentials (SSVEPs) to examine how visual responsiveness in wild-type Drosophila melanogaster and the circadian clock mutant ClkJrk varies over circadian time. We show that the ERG parameters of wild-type flies vary over the circadian day, with a higher luminance response during the subjective night. The SSVEP response that assesses contrast sensitivity also showed a time-of-day dependence, including 2 prominent peaks within a 24-h period and a maximal response at the end of the subjective day, indicating a tradeoff between luminance and contrast sensitivity. Moreover, the behaviorally arrhythmic ClkJrk mutants maintained a circadian profile in both luminance and contrast sensitivity, but unlike the wild-types, which show bimodal profiles in their visual response, ClkJrk flies show a weakening of the bimodal character, with visual responsiveness tending to peak once a day. We conclude that the ClkJrk mutation mainly affects 1 of 2 functionally coupled oscillators and that the visual system is partially separated from the locomotor circadian circuits that drive bouts of morning and evening activity. As light exposure is a major mechanism for entrainment, our work suggests that a detailed temporal analysis of electrophysiological responses is warranted to better identify the time window at which circadian rhythms are most receptive to light-induced phase shifting.
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Affiliation(s)
- Olivia M Nippe
- Department of Biology, University of York, Heslington, York, UK.,1. School of Life Sciences, University of Warwick, Coventry, UK
| | - Alex R Wade
- Department of Psychology, University of York, Heslington, York, UK
| | - Christopher J H Elliott
- Department of Biology, University of York, Heslington, York, UK.,1. School of Life Sciences, University of Warwick, Coventry, UK
| | - Sangeeta Chawla
- Department of Biology, University of York, Heslington, York, UK
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26
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Herrero A, Duhart JM, Ceriani MF. Neuronal and Glial Clocks Underlying Structural Remodeling of Pacemaker Neurons in Drosophila. Front Physiol 2017; 8:918. [PMID: 29184510 PMCID: PMC5694478 DOI: 10.3389/fphys.2017.00918] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/30/2017] [Indexed: 11/24/2022] Open
Abstract
A number of years ago we reported that ventral Lateral Neurons (LNvs), which are essential in the control of rest-activity cycles in Drosophila, undergo circadian remodeling of their axonal projections. This structural plasticity gives rise to changes in the degree of connectivity, which could provide a means of transmitting time of day information. Thus far, work from different laboratories has shown that circadian remodeling of adult projections relies on activity-dependent and -independent mechanisms. In terms of clock- dependent mechanisms, several neuronal types undergoing circadian remodeling hinted to a differential effect of clock genes; while per mutants exhibited poorly developed axonal terminals giving rise to low complexity arbors, tim mutants displayed a characteristic hyper branching phenotype, suggesting these genes could be playing additional roles to those ascribed to core clock function. To shed light onto this possibility we altered clock gene levels through RNAi- mediated downregulation and expression of a dominant negative form exclusively in the adult LNvs. These experiments confirmed that the LNv clock is necessary to drive the remodeling process. We next explored the contribution of glia to the structural plasticity of the small LNvs through acute disruption of their internal clock. Interestingly, impaired glial clocks also abolished circadian structural remodeling, without affecting other clock-controlled outputs. Taken together our data shows that both neuronal and glial clocks are recruited to define the architecture of the LNv projections along the day, thus enabling a precise reconfiguration of the circadian network.
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Affiliation(s)
| | | | - Maria F. Ceriani
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIB-BA CONICET, Buenos Aires, Argentina
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27
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Walkowicz L, Kijak E, Krzeptowski W, Górska-Andrzejak J, Stratoulias V, Woznicka O, Chwastek E, Heino TI, Pyza EM. Downregulation of DmMANF in Glial Cells Results in Neurodegeneration and Affects Sleep and Lifespan in Drosophila melanogaster. Front Neurosci 2017; 11:610. [PMID: 29163014 PMCID: PMC5673640 DOI: 10.3389/fnins.2017.00610] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 10/18/2017] [Indexed: 01/19/2023] Open
Abstract
In Drosophila melanogaster, mesencephalic astrocyte-derived neurotrophic factor (DmMANF) is an evolutionarily conserved ortholog of mammalian MANF and cerebral dopamine neurotrophic factor (CDNF), which have been shown to promote the survival of dopaminergic neurons in the brain. We observed especially high levels of DmMANF in the visual system of Drosophila, particularly in the first optic neuropil (lamina). In the lamina, DmMANF was found in glial cells (surface and epithelial glia), photoreceptors and interneurons. Interestingly, silencing of DmMANF in all neurons or specifically in photoreceptors or L2 interneurons had no impact on the structure of the visual system. However, downregulation of DmMANF in glial cells induced degeneration of the lamina. Remarkably, this degeneration in the form of holes and/or tightly packed membranes was observed only in the lamina epithelial glial cells. Those membranes seem to originate from the endoplasmic reticulum, which forms autophagosome membranes. Moreover, capitate projections, the epithelial glia invaginations into photoreceptor terminals that are involved in recycling of the photoreceptor neurotransmitter histamine, were less numerous after DmMANF silencing either in neurons or glial cells. The distribution of the alpha subunit of Na+/K+-ATPase protein in the lamina cell membranes was also changed. At the behavioral level, silencing of DmMANF either in neurons or glial cells affected the daily activity/sleep pattern, and flies showed less activity during the day but higher activity during the night than did controls. In the case of silencing in glia, the lifespan of flies was also shortened. The obtained results showed that DmMANF regulates many functions in the brain, particularly those dependent on glial cells.
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Affiliation(s)
- Lucyna Walkowicz
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Ewelina Kijak
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Wojciech Krzeptowski
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | | | - Olga Woznicka
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Elzbieta Chwastek
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Tapio I. Heino
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Elzbieta M. Pyza
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
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28
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Plazaola-Sasieta H, Fernández-Pineda A, Zhu Q, Morey M. Untangling the wiring of the Drosophila visual system: developmental principles and molecular strategies. J Neurogenet 2017; 31:231-249. [DOI: 10.1080/01677063.2017.1391249] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Haritz Plazaola-Sasieta
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
| | - Alejandra Fernández-Pineda
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
| | - Qi Zhu
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
| | - Marta Morey
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
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Damulewicz M, Mazzotta GM, Sartori E, Rosato E, Costa R, Pyza EM. Cryptochrome Is a Regulator of Synaptic Plasticity in the Visual System of Drosophila melanogaster. Front Mol Neurosci 2017; 10:165. [PMID: 28611590 PMCID: PMC5448152 DOI: 10.3389/fnmol.2017.00165] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 05/11/2017] [Indexed: 11/25/2022] Open
Abstract
Drosophila CRYPTOCHROME (CRY) is a blue light sensitive protein with a key role in circadian photoreception. A main feature of CRY is that light promotes an interaction with the circadian protein TIMELESS (TIM) resulting in their ubiquitination and degradation, a mechanism that contributes to the synchronization of the circadian clock to the environment. Moreover, CRY participates in non-circadian functions such as magnetoreception, modulation of neuronal firing, phototransduction and regulation of synaptic plasticity. In the present study we used co-immunoprecipitation, yeast 2 hybrid (Y2H) and in situ proximity ligation assay (PLA) to show that CRY can physically associate with the presynaptic protein BRUCHPILOT (BRP) and that CRY-BRP complexes are located mainly in the visual system. Additionally, we present evidence that light-activated CRY may decrease BRP levels in photoreceptor termini in the distal lamina, probably targeting BRP for degradation.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Faculty of Biology and Earth Sciences, Jagiellonian UniversityKrakow, Poland
| | | | - Elena Sartori
- Department of Biology, University of PadovaPadova, Italy
| | - Ezio Rosato
- Department of Genetics, University of Leicester LeicesterUnited Kingdom
| | - Rodolfo Costa
- Department of Biology, University of PadovaPadova, Italy
| | - Elzbieta M. Pyza
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Faculty of Biology and Earth Sciences, Jagiellonian UniversityKrakow, Poland
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Kijak E, Pyza E. TOR signaling pathway and autophagy are involved in the regulation of circadian rhythms in behavior and plasticity of L2 interneurons in the brain of Drosophila melanogaster. PLoS One 2017; 12:e0171848. [PMID: 28196106 PMCID: PMC5308838 DOI: 10.1371/journal.pone.0171848] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 01/26/2017] [Indexed: 12/19/2022] Open
Abstract
Drosophila melanogaster is a common model used to study circadian rhythms in behavior and circadian clocks. However, numerous circadian rhythms have also been detected in non-clock neurons, especially in the first optic neuropil (lamina) of the fly's visual system. Such rhythms have been observed in the number of synapses and in the structure of interneurons, which exhibit changes in size and shape in a circadian manner. Although the patterns of these changes are known, the mechanism remains unclear. In the present study, we investigated the role of the TOR signaling pathway and autophagy in regulating circadian rhythms based on the behavior and structural plasticity of the lamina L2 monopolar cell dendritic trees. In addition, we examined the cyclic expression of the TOR signaling pathway (Tor, Pi3K class 1, Akt1) and autophagy (Atg5 and Atg7) genes in the fly's brain. We observed that Tor, Atg5 and Atg7 exhibit rhythmic expressions in the brain of wild-type flies in day/night conditions (LD 12:12) that are abolished in per01 clock mutants. The silencing of Tor in per expressing cells shortens a period of the locomotor activity rhythm of flies. In addition, silencing of the Tor and Atg5 genes in L2 cells disrupts the circadian plasticity of the L2 cell dendritic trees measured in the distal lamina. In turn, silencing of the Atg7 gene in L2 cells changes the pattern of this rhythm. Our results indicate that the TOR signaling pathway and autophagy are involved in the regulation of circadian rhythms in the behavior and plasticity of neurons in the brain of adult flies.
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Affiliation(s)
- Ewelina Kijak
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Kraków, Poland
| | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Kraków, Poland
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Interactions Between the Circadian Clock and Heme Oxygenase in the Retina of Drosophila melanogaster. Mol Neurobiol 2016; 54:4953-4962. [PMID: 27520276 PMCID: PMC5533861 DOI: 10.1007/s12035-016-0026-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 08/01/2016] [Indexed: 01/14/2023]
Abstract
The Drosophila retina has an autonomous peripheral circadian clock in which the expression of the gene encoding heme oxygenase (HO) is under circadian control with the ho mRNA peaking at the beginning of the day and in the middle of the night. The function of HO in the retina is unknown, but we observed that it regulates the circadian clock and protects photoreceptors against DNA damage. The decline in HO level increases and decreases the expression of the canonical clock genes period (per) and Clock (Clk), respectively. The opposite result was observed after increasing HO expression. Among three products of HO activity—carbon monoxide (CO), ferrous ions, and biliverdin—the latter has no effect on per and Clk expressions, but CO exerts the same effect as the increase of ho expression. This suggests that HO action on the clock is mediated by CO, which may affect Clk expression during the day and the level of per expression. While ho expression is not stimulated by nitric oxide (NO), NO has the same effect on the clock as HO, increasing Clk expression and decreasing the expression of per.
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Nijhof B, Castells-Nobau A, Wolf L, Scheffer-de Gooyert JM, Monedero I, Torroja L, Coromina L, van der Laak JAWM, Schenck A. A New Fiji-Based Algorithm That Systematically Quantifies Nine Synaptic Parameters Provides Insights into Drosophila NMJ Morphometry. PLoS Comput Biol 2016; 12:e1004823. [PMID: 26998933 PMCID: PMC4801422 DOI: 10.1371/journal.pcbi.1004823] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/19/2016] [Indexed: 11/20/2022] Open
Abstract
The morphology of synapses is of central interest in neuroscience because of the intimate relation with synaptic efficacy. Two decades of gene manipulation studies in different animal models have revealed a repertoire of molecules that contribute to synapse development. However, since such studies often assessed only one, or at best a few, morphological features at a given synapse, it remained unaddressed how different structural aspects relate to one another. Furthermore, such focused and sometimes only qualitative approaches likely left many of the more subtle players unnoticed. Here, we present the image analysis algorithm 'Drosophila_NMJ_Morphometrics', available as a Fiji-compatible macro, for quantitative, accurate and objective synapse morphometry of the Drosophila larval neuromuscular junction (NMJ), a well-established glutamatergic model synapse. We developed this methodology for semi-automated multiparametric analyses of NMJ terminals immunolabeled for the commonly used markers Dlg1 and Brp and showed that it also works for Hrp, Csp and Syt. We demonstrate that gender, genetic background and identity of abdominal body segment consistently and significantly contribute to variability in our data, suggesting that controlling for these parameters is important to minimize variability in quantitative analyses. Correlation and principal component analyses (PCA) were performed to investigate which morphometric parameters are inter-dependent and which ones are regulated rather independently. Based on nine acquired parameters, we identified five morphometric groups: NMJ size, geometry, muscle size, number of NMJ islands and number of active zones. Based on our finding that the parameters of the first two principal components hardly correlated with each other, we suggest that different molecular processes underlie these two morphometric groups. Our study sets the stage for systems morphometry approaches at the well-studied Drosophila NMJ.
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Affiliation(s)
- Bonnie Nijhof
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anna Castells-Nobau
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Louis Wolf
- Microscopical Imaging Centre (MIC), Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jolanda M. Scheffer-de Gooyert
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ignacio Monedero
- Department of Biology, Universidad Autónoma de Madrid, Madrid, Spain
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Laura Torroja
- Department of Biology, Universidad Autónoma de Madrid, Madrid, Spain
| | - Lluis Coromina
- Research Group on Statistics, Econometrics and Health (GRECS) and CIBER of Epidemiology and Public Health (CIBERESP), University of Girona, Girona, Spain
| | - Jeroen A. W. M. van der Laak
- Microscopical Imaging Centre (MIC), Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Pathology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
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Damulewicz M, Loboda A, Bukowska-Strakova K, Jozkowicz A, Dulak J, Pyza E. Clock and clock-controlled genes are differently expressed in the retina, lamina and in selected cells of the visual system of Drosophila melanogaster. Front Cell Neurosci 2015; 9:353. [PMID: 26441524 PMCID: PMC4569741 DOI: 10.3389/fncel.2015.00353] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 08/24/2015] [Indexed: 11/13/2022] Open
Abstract
The retina and the first optic neuropil (lamina) of Drosophila show circadian rhythms in various processes. To learn about the regulation of circadian rhythms in the retina and lamina and in two cell types, glial and the lamina L2 interneurons, we examined expression of the following clock genes; per, tim, clk, and cry and clock-controlled genes (ccgs); Atpα, nrv2, brp, Pdfr. We found that the expression of gene studied is specific for the retina and lamina. The rhythms of per and tim expression in the retina and glial cells are similar to that observed in the whole head and in clock neurons, while they differ in the lamina and L2 cells. In both the retina and lamina, CRY seems to be a repressor of clk expression. In L2 interneurons per expression is not cyclic indicating the other function of PER in those cells than in the circadian molecular clock. In contrast to per and tim, the pattern of clk and cry expression is similar in both the retina and lamina. The retina holds the autonomous oscillators but the expression of cry and ccgs, Atpα and nrv2, is also regulated by inputs from the pacemaker transmitted by PDF and ITP neuropeptides.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Institute of Zoology, Faculty of Biology and Earth Sciences, Jagiellonian University Krakow, Poland
| | - Agnieszka Loboda
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Krakow, Poland
| | - Karolina Bukowska-Strakova
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Krakow, Poland ; Department of Clinical Immunology and Transplantology, Polish-American Institute of Pediatrics, Medical College, Jagiellonian University Krakow, Poland
| | - Alicja Jozkowicz
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Krakow, Poland
| | - Jozef Dulak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Krakow, Poland
| | - Elzbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Faculty of Biology and Earth Sciences, Jagiellonian University Krakow, Poland
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Rodríguez-Muñoz MDLP, Escamilla-Chimal EG. Glial fibrillary acidic protein (GFAP) shows circadian oscillations in crayfishProcambarus clarkiiputative pacemakers. Chronobiol Int 2015; 32:1135-44. [DOI: 10.3109/07420528.2015.1071385] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Bosler O, Girardet C, Franc JL, Becquet D, François-Bellan AM. Structural plasticity of the circadian timing system. An overview from flies to mammals. Front Neuroendocrinol 2015; 38:50-64. [PMID: 25703789 DOI: 10.1016/j.yfrne.2015.02.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 02/10/2015] [Accepted: 02/11/2015] [Indexed: 12/22/2022]
Abstract
The circadian timing system orchestrates daily variations in physiology and behavior through coordination of multioscillatory cell networks that are highly plastic in responding to environmental changes. Over the last decade, it has become clear that this plasticity involves structural changes and that the changes may be observed not only in central brain regions where the master clock cells reside but also in clock-controlled structures. This review considers experimental data in invertebrate and vertebrate model systems, mainly flies and mammals, illustrating various forms of structural circadian plasticity from cellular to circuit-based levels. It highlights the importance of these plastic events in the functional adaptation of the clock to the changing environment.
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Affiliation(s)
- Olivier Bosler
- Aix-Marseille Université, CNRS, CRN2M, UMR 7286, Faculté de médecine, secteur nord, Boulevard Pierre Dramard, CS 80011, F-13344 Marseille cedex 15, France.
| | - Clémence Girardet
- Aix-Marseille Université, CNRS, CRN2M, UMR 7286, Faculté de médecine, secteur nord, Boulevard Pierre Dramard, CS 80011, F-13344 Marseille cedex 15, France.
| | - Jean-Louis Franc
- Aix-Marseille Université, CNRS, CRN2M, UMR 7286, Faculté de médecine, secteur nord, Boulevard Pierre Dramard, CS 80011, F-13344 Marseille cedex 15, France
| | - Denis Becquet
- Aix-Marseille Université, CNRS, CRN2M, UMR 7286, Faculté de médecine, secteur nord, Boulevard Pierre Dramard, CS 80011, F-13344 Marseille cedex 15, France
| | - Anne-Marie François-Bellan
- Aix-Marseille Université, CNRS, CRN2M, UMR 7286, Faculté de médecine, secteur nord, Boulevard Pierre Dramard, CS 80011, F-13344 Marseille cedex 15, France
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Woźnicka O, Görlich A, Sigrist S, Pyza E. BRP-170 and BRP190 isoforms of Bruchpilot protein differentially contribute to the frequency of synapses and synaptic circadian plasticity in the visual system of Drosophila. Front Cell Neurosci 2015; 9:238. [PMID: 26175667 PMCID: PMC4485229 DOI: 10.3389/fncel.2015.00238] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 06/12/2015] [Indexed: 11/13/2022] Open
Abstract
In the first optic neuropil (lamina) of the optic lobe of Drosophila melanogaster, two classes of synapses, tetrad and feedback, show daily rhythms in the number and size of presynaptic profiles examined at the level of transmission electron microscopy (TEM). Number of tetrad presynaptic profiles increases twice a day, once in the morning and again in the evening, and their presynaptic ribbons are largest in the evening. In contrast, feedback synapses peak at night. The frequency of synapses is correlated with size of the presynaptic element measured as the platform size of so-called T-bars, with T-bar platforms being largest with increasing synapse frequency. The large scaffold protein Bruchpilot (BRP) is a major essential constituent of T-bars, with two major isoforms of 190 and 170 kD forming T-bars of the peripheral neuromuscular junctions (NMJ) synapses and in the brain. In addition to the analysis of cyclic plasticity of tetrad and feedback synapses in wild-type flies, we used TEM to examine daily changes in the size and distribution of synapses within isoform-specific BRP mutants, expressing BRP-190 (BRPΔ170) or BRP-170 (BRPΔ190) only. We found that the number and circadian plasticity of synapses depends on both isoforms. In the BRPΔ190 lacking BRP-190 there was almost 50% less tetrad synapses demonstrable than when both isoforms were present. The lack of BRP-170 and BRP-190 increased and decreased, respectively the number of feedback synapses, indicating that BRP-190 forms most of the feedback synapses. In both mutants, the daily plasticity of tetrad and feedback presynaptic profiles was abolished, except for feedback synapses in BRPΔ190. The oscillations in the number and size of presynaptic elements seem to depend on a different contribution of BRP isoforms in a presynaptic element at different time during the day and night and at various synapse types. The participation of both BRP isoforms may vary in different classes of synapses.
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Affiliation(s)
- Olga Woźnicka
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Krakow, Poland
| | - Alicja Görlich
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Krakow, Poland
| | - Stephan Sigrist
- Neurogenetik, Institut für Biologie, Freie Universität Berlin Berlin, Germany ; NeuroCure and Institut für Medizinische Physik and Biophysik, Charité-Universitätsmedizin Berlin Berlin, Germany
| | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Krakow, Poland
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Sugie A, Hakeda-Suzuki S, Suzuki E, Silies M, Shimozono M, Möhl C, Suzuki T, Tavosanis G. Molecular Remodeling of the Presynaptic Active Zone of Drosophila Photoreceptors via Activity-Dependent Feedback. Neuron 2015; 86:711-25. [PMID: 25892303 DOI: 10.1016/j.neuron.2015.03.046] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 02/10/2015] [Accepted: 03/18/2015] [Indexed: 11/27/2022]
Abstract
Neural activity contributes to the regulation of the properties of synapses in sensory systems, allowing for adjustment to a changing environment. Little is known about how synaptic molecular components are regulated to achieve activity-dependent plasticity at central synapses. Here, we found that after prolonged exposure to natural ambient light the presynaptic active zone in Drosophila photoreceptors undergoes reversible remodeling, including loss of Bruchpilot, DLiprin-α, and DRBP, but not of DSyd-1 or Cacophony. The level of depolarization of the postsynaptic neurons is critical for the light-induced changes in active zone composition in the photoreceptors, indicating the existence of a feedback signal. In search of this signal, we have identified a crucial role of microtubule meshwork organization downstream of the divergent canonical Wnt pathway, potentially via Kinesin-3 Imac. These data reveal that active zone composition can be regulated in vivo and identify the underlying molecular machinery.
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Affiliation(s)
- Atsushi Sugie
- Dendrite Differentiation, German Center for Neurodegenerative Diseases (DZNE), Bonn 53175, Germany
| | - Satoko Hakeda-Suzuki
- Core Division of Advanced Research, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology (Titech), Yokohama 226-8501, Japan
| | - Emiko Suzuki
- Gene Network Laboratory, National Institute of Genetics and Department of Genetics, SOKENDAI, Mishima 411-8540, Japan
| | - Marion Silies
- European Neuroscience Institute (ENI), 37077 Göttingen, Germany
| | - Mai Shimozono
- Core Division of Advanced Research, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology (Titech), Yokohama 226-8501, Japan
| | - Christoph Möhl
- Image and Data Analysis Facility, German Center for Neurodegenerative Diseases (DZNE), Bonn 53175, Germany
| | - Takashi Suzuki
- Core Division of Advanced Research, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology (Titech), Yokohama 226-8501, Japan.
| | - Gaia Tavosanis
- Dendrite Differentiation, German Center for Neurodegenerative Diseases (DZNE), Bonn 53175, Germany.
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Górska-Andrzejak J, Damulewicz M, Pyza E. Circadian changes in neuronal networks. CURRENT OPINION IN INSECT SCIENCE 2015; 7:76-81. [PMID: 32846686 DOI: 10.1016/j.cois.2015.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/10/2015] [Accepted: 01/13/2015] [Indexed: 06/11/2023]
Abstract
The circadian clock generates circadian plasticity in some of the clock and non-clock neurons leading to the daily changes in their structure and in the number of synaptic contacts. This plasticity affects neuronal networks in the brain. The two best known examples of circadian changes in neuronal networks are those observed in the first optic neuropil (lamina) of the fly's visual system and between one group of clock neurons, the small ventral lateral neurons (s-LNvs), and their target cells in the dorsal part of the Drosophila brain. Both of these networks are remodeled in the course of the day by the circadian clock and they are further affected by external stimuli.
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Affiliation(s)
- Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Milena Damulewicz
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Krakow, Poland.
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Wernitznig S, Rind FC, Pölt P, Zankel A, Pritz E, Kolb D, Bock E, Leitinger G. Synaptic connections of first-stage visual neurons in the locust Schistocerca gregaria extend evolution of tetrad synapses back 200 million years. J Comp Neurol 2014; 523:298-312. [PMID: 25255709 DOI: 10.1002/cne.23682] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/18/2014] [Accepted: 09/19/2014] [Indexed: 02/02/2023]
Abstract
The small size of some insects, and the crystalline regularity of their eyes, have made them ideal for large-scale reconstructions of visual circuits. In phylogenetically recent muscomorph flies, like Drosophila, precisely coordinated output to different motion-processing pathways is delivered by photoreceptors (R cells), targeting four different postsynaptic cells at each synapse (tetrad). Tetrads were linked to the evolution of aerial agility. To reconstruct circuits for vision in the larger brain of a locust, a phylogenetically old, flying insect, we adapted serial block-face scanning electron microscopy (SBEM). Locust lamina monopolar cells, L1 and L2, were the main targets of the R cell pathway, L1 and L2 each fed a different circuit, only L1 providing feedback onto R cells. Unexpectedly, 40% of all locust R cell synapses onto both L1 and L2 were tetrads, revealing the emergence of tetrads in an arthropod group present 200 million years before muscomorph flies appeared, coinciding with the early evolution of flight.
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Affiliation(s)
- Stefan Wernitznig
- Institute of Cell Biology, Histology and Embryology, Research Unit Electron Microscopic Techniques, Medical University of Graz, 8010, Graz, Austria
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Gorostiza EA, Depetris-Chauvin A, Frenkel L, Pírez N, Ceriani MF. Circadian pacemaker neurons change synaptic contacts across the day. Curr Biol 2014; 24:2161-2167. [PMID: 25155512 DOI: 10.1016/j.cub.2014.07.063] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 06/14/2014] [Accepted: 07/23/2014] [Indexed: 12/19/2022]
Abstract
Daily cycles of rest and activity are a common example of circadian control of physiology. In Drosophila, rhythmic locomotor cycles rely on the activity of 150-200 neurons grouped in seven clusters [1, 2]. Work from many laboratories points to the small ventral lateral neurons (sLNvs) as essential for circadian control of locomotor rhythmicity [3-7]. sLNv neurons undergo circadian remodeling of their axonal projections, opening the possibility for a circadian control of connectivity of these relevant circadian pacemakers [8]. Here we show that circadian plasticity of the sLNv axonal projections has further implications than mere structural changes. First, we found that the degree of daily structural plasticity exceeds that originally described [8], underscoring that changes in the degree of fasciculation as well as extension or pruning of axonal terminals could be involved. Interestingly, the quantity of active zones changes along the day, lending support to the attractive hypothesis that new synapses are formed while others are dismantled between late night and the following morning. More remarkably, taking full advantage of the GFP reconstitution across synaptic partners (GRASP) technique [9], we showed that, in addition to new synapses being added or removed, sLNv neurons contact different synaptic partners at different times along the day. These results lead us to propose that the circadian network, and in particular the sLNv neurons, orchestrates some of the physiological and behavioral differences between day and night by changing the path through which information travels.
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Affiliation(s)
- E Axel Gorostiza
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas-Buenos Aires (IIB-BA, CONICET), Avenida Patricias Argentinas 435, 1405-BWE Buenos Aires, Argentina
| | - Ana Depetris-Chauvin
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas-Buenos Aires (IIB-BA, CONICET), Avenida Patricias Argentinas 435, 1405-BWE Buenos Aires, Argentina
| | - Lia Frenkel
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas-Buenos Aires (IIB-BA, CONICET), Avenida Patricias Argentinas 435, 1405-BWE Buenos Aires, Argentina
| | - Nicolás Pírez
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas-Buenos Aires (IIB-BA, CONICET), Avenida Patricias Argentinas 435, 1405-BWE Buenos Aires, Argentina
| | - María Fernanda Ceriani
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas-Buenos Aires (IIB-BA, CONICET), Avenida Patricias Argentinas 435, 1405-BWE Buenos Aires, Argentina.
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Lüthy K, Ahrens B, Rawal S, Lu Z, Tarnogorska D, Meinertzhagen IA, Fischbach KF. The irre cell recognition module (IRM) protein Kirre is required to form the reciprocal synaptic network of L4 neurons in the Drosophila lamina. J Neurogenet 2014; 28:291-301. [PMID: 24697410 DOI: 10.3109/01677063.2014.883390] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Each neuropil module, or cartridge, in the fly's lamina has a fixed complement of cells. Of five types of monopolar cell interneurons, only L4 has collaterals that invade neighboring cartridges. In the proximal lamina, these collaterals form reciprocal synapses with both the L2 of their own cartridge and the L4 collateral branches from two other neighboring cartridges. During synaptogenesis, L4 collaterals strongly express the cell adhesion protein Kirre, a member of the irre cell recognition module (IRM) group of proteins ( Fischbach et al., 2009 , J Neurogenet, 23, 48-67). The authors show by mutant analysis and gene knockdown techniques that L4 neurons develop their lamina collaterals in the absence of this cell adhesion protein. Using electron microscopy (EM), the authors demonstrate, however, that without Kirre protein these L4 collaterals selectively form fewer synapses. The collaterals of L4 neurons of various genotypes reconstructed from serial-section EM revealed that the number of postsynaptic sites was dramatically reduced in the absence of Kirre, almost eliminating any synaptic input to L4 neurons. A significant reduction of presynaptic sites was also detected in kirre(0) mutants and gene knockdown flies using RNA interference. L4 neuron reciprocal synapses are thus almost eliminated. A presynaptic marker, Brp-short(GFP) confirmed these data using confocal microscopy. This study reveals that removing Kirre protein specifically disrupts the functional L4 synaptic network in the Drosophila lamina.
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Affiliation(s)
- Kevin Lüthy
- Faculty of Biology, Albert-Ludwigs University Freiburg , Germany
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Krzeptowski W, Górska-Andrzejak J, Kijak E, Görlich A, Guzik E, Moore G, Pyza EM. External and circadian inputs modulate synaptic protein expression in the visual system of Drosophila melanogaster. Front Physiol 2014; 5:102. [PMID: 24772085 PMCID: PMC3982107 DOI: 10.3389/fphys.2014.00102] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 02/28/2014] [Indexed: 12/30/2022] Open
Abstract
In the visual system of Drosophila melanogaster the retina photoreceptors form tetrad synapses with the first order interneurons, amacrine cells and glial cells in the first optic neuropil (lamina), in order to transmit photic and visual information to the brain. Using the specific antibodies against synaptic proteins; Bruchpilot (BRP), Synapsin (SYN), and Disc Large (DLG), the synapses in the distal lamina were specifically labeled. Then their abundance was measured as immunofluorescence intensity in flies held in light/dark (LD 12:12), constant darkness (DD), and after locomotor and light stimulation. Moreover, the levels of proteins (SYN and DLG), and mRNAs of the brp, syn, and dlg genes, were measured in the fly's head and brain, respectively. In the head we did not detect SYN and DLG oscillations. We found, however, that in the lamina, DLG oscillates in LD 12:12 and DD but SYN cycles only in DD. The abundance of all synaptic proteins was also changed in the lamina after locomotor and light stimulation. One hour locomotor stimulations at different time points in LD 12:12 affected the pattern of the daily rhythm of synaptic proteins. In turn, light stimulations in DD increased the level of all proteins studied. In the case of SYN, however, this effect was observed only after a short light pulse (15 min). In contrast to proteins studied in the lamina, the mRNA of brp, syn, and dlg genes in the brain was not cycling in LD 12:12 and DD, except the mRNA of dlg in LD 12:12. Our earlier results and obtained in the present study showed that the abundance of BRP, SYN and DLG in the distal lamina, at the tetrad synapses, is regulated by light and a circadian clock while locomotor stimulation affects their daily pattern of expression. The observed changes in the level of synaptic markers reflect the circadian plasticity of tetrad synapses regulated by the circadian clock and external inputs, both specific and unspecific for the visual system.
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Affiliation(s)
- Wojciech Krzeptowski
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Ewelina Kijak
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Alicja Görlich
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Elżbieta Guzik
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Gareth Moore
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Elżbieta M Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
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Wairkar YP, Trivedi D, Natarajan R, Barnes K, Dolores L, Cho P. CK2α regulates the transcription of BRP in Drosophila. Dev Biol 2013; 384:53-64. [PMID: 24080510 DOI: 10.1016/j.ydbio.2013.09.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 09/18/2013] [Accepted: 09/20/2013] [Indexed: 01/26/2023]
Abstract
Development and plasticity of synapses are brought about by a complex interplay between various signaling pathways. Typically, either changing the number of synapses or strengthening an existing synapse can lead to changes during synaptic plasticity. Altering the machinery that governs the exocytosis of synaptic vesicles, which primarily fuse at specialized structures known as active zones on the presynaptic terminal, brings about these changes. Although signaling pathways that regulate the synaptic plasticity from the postsynaptic compartments are well defined, the pathways that control these changes presynaptically are poorly described. In a genetic screen for synapse development in Drosophila, we found that mutations in CK2α lead to an increase in the levels of Bruchpilot (BRP), a scaffolding protein associated with the active zones. Using a combination of genetic and biochemical approaches, we found that the increase in BRP in CK2α mutants is largely due to an increase in the transcription of BRP. Interestingly, the transcripts of other active zone proteins that are important for function of active zones were also increased, while the transcripts from some other synaptic proteins were unchanged. Thus, our data suggest that CK2α might be important in regulating synaptic plasticity by modulating the transcription of BRP. Hence, we propose that CK2α is a novel regulator of the active zone protein, BRP, in Drosophila.
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Affiliation(s)
- Yogesh P Wairkar
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd., Rte#1045, Galveston, TX 77555, United States.
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Damulewicz M, Rosato E, Pyza E. Circadian regulation of the Na+/K+-ATPase alpha subunit in the visual system is mediated by the pacemaker and by retina photoreceptors in Drosophila melanogaster. PLoS One 2013; 8:e73690. [PMID: 24040028 PMCID: PMC3769360 DOI: 10.1371/journal.pone.0073690] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 07/29/2013] [Indexed: 12/20/2022] Open
Abstract
We investigated the diurnal oscillation in abundance of the catalytic α subunit of the sodium/potassium pump (ATPα) in the brain of Drosophila melanogaster. This rhythm is bimodal and is particularly robust in the glia cells of the lamina, the first optic neuropil. We observed loss of ATPα cycling in lamina glia in behaviourally arrhythmic per01 and tim01 mutants and in flies overexpressing the pro-apoptotic gene hid in the PDF-positive clock neurons. Moreover, the rhythm of ATPα abundance was altered in cry01 and Pdf0 mutants, in flies with a weakened clock mechanism in retina photoreceptor cells and in those subject to downregulation of the neuropeptide ITP by RNAi. This complex, rhythmic regulation of the α subunit suggests that the sodium/potassium pump may be a key target of the circadian pacemaker to impose daily control on brain activities, such as rhythmic changes in neuronal plasticity, which are best observed in the visual system.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Kraków, Poland
| | - Ezio Rosato
- Department of Genetics, University of Leicester, Leicester, United Kingdom
| | - Elzbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Kraków, Poland
- * E-mail:
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Górska-Andrzejak J. Glia-related circadian plasticity in the visual system of Diptera. Front Physiol 2013; 4:36. [PMID: 23986707 PMCID: PMC3750947 DOI: 10.3389/fphys.2013.00036] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/13/2013] [Indexed: 11/28/2022] Open
Abstract
The circadian changes in morphology of the first visual neuropil or lamina of Diptera represent an example of the neuronal plasticity controlled by the circadian clock (circadian plasticity). It is observed in terminals of the compound eye photoreceptor cells, the peripheral oscillators expressing the clock genes. However, it has been found also in their postsynaptic partners, the L1 and L2 monopolar cells, in which the activity of the clock genes have not yet been detected. The circadian input that the L1 and L2 receive seems to originate not only from the retina photoreceptors and from the circadian pacemaker neurons located in the brain, but also from the glial cells that express the clock genes and thus contain circadian oscillators. This paper summarizes the morphological and biochemical rhythms in glia of the optic lobe, shows how they contribute to circadian plasticity, and discusses how glial clocks may modulate circadian rhythms in the lamina.
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Affiliation(s)
- Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
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Muraro NI, Pírez N, Ceriani MF. The circadian system: plasticity at many levels. Neuroscience 2013; 247:280-93. [PMID: 23727010 DOI: 10.1016/j.neuroscience.2013.05.036] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 05/17/2013] [Accepted: 05/20/2013] [Indexed: 11/16/2022]
Abstract
Over the years it has become crystal clear that a variety of processes encode time-of-day information, ranging from gene expression, protein stability, or subcellular localization of key proteins, to the fine tuning of network properties and modulation of input signals, ultimately ensuring that physiology and behavior are properly synchronized to a changing environment. The purpose of this review is to put forward examples (as opposed to generate a comprehensive revision of all the available literature) in which the circadian system displays a remarkable degree of plasticity, from cell autonomous to circuit-based levels. In the literature, the term circadian plasticity has been used to refer to different concepts. The obvious one, more literally, refers to any change that follows a circadian (circa=around, diem=day) pattern, i.e. a daily change of a given parameter. The discovery of daily remodeling of neuronal structures will be referred herein as structural circadian plasticity, and represents an additional and novel phenomenon modified daily. Finally, any plasticity that has to do with a circadian parameter would represent a type of circadian plasticity; as an example, adjustments that allow organisms to adapt their daily behavior to the annual changes in photoperiod is a form of circadian plasticity at a higher organizational level, which is an emergent property of the whole circadian system. Throughout this work we will revisit these types of changes by reviewing recent literature delving around circadian control of clock outputs, from the most immediate ones within pacemaker neurons to the circadian modulation of rest-activity cycles.
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Affiliation(s)
- N I Muraro
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIB-BA-CONICET, Buenos Aires, Argentina
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