1
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Boto T, Tomchik SM. Functional Imaging of Learning-Induced Plasticity in the Central Nervous System with Genetically Encoded Reporters in Drosophila. Cold Spring Harb Protoc 2024; 2024:pdb.top107799. [PMID: 37197830 DOI: 10.1101/pdb.top107799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Learning and memory allow animals to adjust their behavior based on the predictive value of their past experiences. Memories often exist in complex representations, spread across numerous cells and synapses in the brain. Studying relatively simple forms of memory provides insights into the fundamental processes that underlie multiple forms of memory. Associative learning occurs when an animal learns the relationship between two previously unrelated sensory stimuli, such as when a hungry animal learns that a particular odor is followed by a tasty reward. Drosophila is a particularly powerful model to study how this type of memory works. The fundamental principles are widely shared among animals, and there is a wide range of genetic tools available to study circuit function in flies. In addition, the olfactory structures that mediate associative learning in flies, such as the mushroom body and its associated neurons, are anatomically organized, relatively well-characterized, and readily accessible to imaging. Here, we review the olfactory anatomy and physiology of the olfactory system, describe how plasticity in the olfactory pathway mediates learning and memory, and explain the general principles underlying calcium imaging approaches.
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Affiliation(s)
- Tamara Boto
- Department of Physiology, Trinity College Dublin, Dublin 2, Ireland
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Seth M Tomchik
- Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
- Stead Family Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
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2
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Frighetto G, Zordan MA, Castiello U, Megighian A, Martin JR. Dopamine Modulation of Drosophila Ellipsoid Body Neurons, a Nod to the Mammalian Basal Ganglia. Front Physiol 2022; 13:849142. [PMID: 35492587 PMCID: PMC9048027 DOI: 10.3389/fphys.2022.849142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/10/2022] [Indexed: 12/04/2022] Open
Abstract
The central complex (CX) is a neural structure located on the midline of the insect brain that has been widely studied in the last few years. Its role in navigation and goal-oriented behaviors resembles those played by the basal ganglia in mammals. However, the neural mechanisms and the neurotransmitters involved in these processes remain unclear. Here, we exploited an in vivo bioluminescence Ca2+ imaging technique to record the activity in targeted neurons of the ellipsoid body (EB). We used different drugs to evoke excitatory Ca2+-responses, depending on the putative neurotransmitter released by their presynaptic inputs, while concomitant dopamine administration was employed to modulate those excitations. By using a genetic approach to knockdown the dopamine 1-like receptors, we showed that different dopamine modulatory effects are likely due to specific receptors expressed by the targeted population of neurons. Altogether, these results provide new data concerning how dopamine modulates and shapes the response of the ellipsoid body neurons. Moreover, they provide important insights regarding the similitude with mammals as far as the role played by dopamine in increasing and stabilizing the response of goal-related information.
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Affiliation(s)
- Giovanni Frighetto
- Department of General Psychology, University of Padova, Padova, Italy
- Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, CNRS, Saclay, France
| | - Mauro A. Zordan
- Department of Biology, University of Padova, Padova, Italy
- Padova Neuroscience Center, University of Padova, Padova, Italy
| | - Umberto Castiello
- Department of General Psychology, University of Padova, Padova, Italy
| | - Aram Megighian
- Padova Neuroscience Center, University of Padova, Padova, Italy
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Jean-René Martin
- Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, CNRS, Saclay, France
- *Correspondence: Jean-René Martin,
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3
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Formicola N, Heim M, Dufourt J, Lancelot AS, Nakamura A, Lagha M, Besse F. Tyramine induces dynamic RNP granule remodeling and translation activation in the Drosophila brain. eLife 2021; 10:65742. [PMID: 33890854 PMCID: PMC8064753 DOI: 10.7554/elife.65742] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/04/2021] [Indexed: 02/06/2023] Open
Abstract
Ribonucleoprotein (RNP) granules are dynamic condensates enriched in regulatory RNA binding proteins (RBPs) and RNAs under tight spatiotemporal control. Extensive recent work has investigated the molecular principles underlying RNP granule assembly, unraveling that they form through the self-association of RNP components into dynamic networks of interactions. How endogenous RNP granules respond to external stimuli to regulate RNA fate is still largely unknown. Here, we demonstrate through high-resolution imaging of intact Drosophila brains that Tyramine induces a reversible remodeling of somatic RNP granules characterized by the decondensation of granule-enriched RBPs (e.g. Imp/ZBP1/IGF2BP) and helicases (e.g. Me31B/DDX-6/Rck). Furthermore, our functional analysis reveals that Tyramine signals both through its receptor TyrR and through the calcium-activated kinase CamkII to trigger RNP component decondensation. Finally, we uncover that RNP granule remodeling is accompanied by the rapid and specific translational activation of associated mRNAs. Thus, this work sheds new light on the mechanisms controlling cue-induced rearrangement of physiological RNP condensates.
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Affiliation(s)
- Nadia Formicola
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Marjorie Heim
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Jérémy Dufourt
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, Montpellier, France
| | - Anne-Sophie Lancelot
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Akira Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, and Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Mounia Lagha
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, Montpellier, France
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
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4
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Kim HS, Kim JE, Hwangbo A, Akerboom J, Looger LL, Duncan R, Son H, Czymmek KJ, Kang S. Evaluation of multi-color genetically encoded Ca 2+ indicators in filamentous fungi. Fungal Genet Biol 2021; 149:103540. [PMID: 33607281 DOI: 10.1016/j.fgb.2021.103540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 11/18/2022]
Abstract
Genetically encoded Ca2+ indicators (GECIs) enable long-term monitoring of cellular and subcellular dynamics of this second messenger in response to environmental and developmental cues without relying on exogenous dyes. Continued development and optimization in GECIs, combined with advances in gene manipulation, offer new opportunities for investigating the mechanism of Ca2+ signaling in fungi, ranging from documenting Ca2+ signatures under diverse conditions and genetic backgrounds to evaluating how changes in Ca2+ signature impact calcium-binding proteins and subsequent cellular changes. Here, we attempted to express multi-color (green, yellow, blue, cyan, and red) circularly permuted fluorescent protein (FP)-based Ca2+ indicators driven by multiple fungal promoters in Fusarium oxysporum, F. graminearum, and Neurospora crassa. Several variants were successfully expressed, with GCaMP5G driven by the Magnaporthe oryzae ribosomal protein 27 and F. verticillioides elongation factor-1α gene promoters being optimal for F. graminearum and F. oxysporum, respectively. Transformants expressing GCaMP5G were compared with those expressing YC3.60, a ratiometric Cameleon Ca2+ indicator. Wild-type and three Ca2+ signaling mutants of F. graminearum expressing GCaMP5G exhibited improved signal-to-noise and increased temporal and spatial resolution and are also more amenable to studies involving multiple FPs compared to strains expressing YC3.60.
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Affiliation(s)
- Hye-Seon Kim
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States; Delaware Biotechnology Institute, Newark, DE 19711, United States
| | - Jung-Eun Kim
- Department of Plant Pathology & Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, United States
| | - Aram Hwangbo
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea
| | - Jasper Akerboom
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, United States
| | - Loren L Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, United States
| | - Randall Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States
| | - Hokyoung Son
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea
| | - Kirk J Czymmek
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States; Delaware Biotechnology Institute, Newark, DE 19711, United States; Donald Danforth Plant Science Center, Saint Louis, MO 63132, United States.
| | - Seogchan Kang
- Department of Plant Pathology & Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, United States.
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5
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RedquorinXS Mutants with Enhanced Calcium Sensitivity and Bioluminescence Output Efficiently Report Cellular and Neuronal Network Activities. Int J Mol Sci 2020; 21:ijms21217846. [PMID: 33105848 PMCID: PMC7660078 DOI: 10.3390/ijms21217846] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/16/2020] [Accepted: 10/19/2020] [Indexed: 01/14/2023] Open
Abstract
Considerable efforts have been focused on shifting the wavelength of aequorin Ca2+-dependent blue bioluminescence through fusion with fluorescent proteins. This approach has notably yielded the widely used GFP-aequorin (GA) Ca2+ sensor emitting green light, and tdTomato-aequorin (Redquorin), whose bioluminescence is completely shifted to red, but whose Ca2+ sensitivity is low. In the present study, the screening of aequorin mutants generated at twenty-four amino acid positions in and around EF-hand Ca2+-binding domains resulted in the isolation of six aequorin single or double mutants (AequorinXS) in EF2, EF3, and C-terminal tail, which exhibited markedly higher Ca2+ sensitivity than wild-type aequorin in vitro. The corresponding Redquorin mutants all showed higher Ca2+ sensitivity than wild-type Redquorin, and four of them (RedquorinXS) matched the Ca2+ sensitivity of GA in vitro. RedquorinXS mutants exhibited unaltered thermostability and peak emission wavelengths. Upon stable expression in mammalian cell line, all RedquorinXS mutants reported the activation of the P2Y2 receptor by ATP with higher sensitivity and assay robustness than wt-Redquorin, and one, RedquorinXS-Q159T, outperformed GA. Finally, wide-field bioluminescence imaging in mouse neocortical slices showed that RedquorinXS-Q159T and GA similarly reported neuronal network activities elicited by the removal of extracellular Mg2+. Our results indicate that RedquorinXS-Q159T is a red light-emitting Ca2+ sensor suitable for the monitoring of intracellular signaling in a variety of applications in cells and tissues, and is a promising candidate for the transcranial monitoring of brain activities in living mice.
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6
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Tricoire L, Drobac E, Tsuzuki K, Gallopin T, Picaud S, Cauli B, Rossier J, Lambolez B. Bioluminescence calcium imaging of network dynamics and their cholinergic modulation in slices of cerebral cortex from male rats. J Neurosci Res 2019; 97:414-432. [PMID: 30604494 DOI: 10.1002/jnr.24380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 11/27/2018] [Accepted: 12/11/2018] [Indexed: 12/12/2022]
Abstract
The activity of neuronal ensembles was monitored in neocortical slices from male rats using wide-field bioluminescence imaging of a calcium sensor formed with the fusion of green fluorescent protein and aequorin (GA) and expressed through viral transfer. GA expression was restricted to pyramidal neurons and did not conspicuously alter neuronal morphology or neocortical cytoarchitecture. Removal of extracellular magnesium or addition of GABA receptor antagonists triggered epileptiform flashes of variable amplitude and spatial extent, indicating that the excitatory and inhibitory networks were functionally preserved in GA-expressing slices. We found that agonists of muscarinic acetylcholine receptors largely increased the peak bioluminescence response to local electrical stimulation in layer I or white matter, and gave rise to a slowly decaying response persisting for tens of seconds. The peak increase involved layers II/III and V and did not result in marked alteration of response spatial properties. The persistent response involved essentially layer V and followed the time course of the muscarinic afterdischarge depolarizing plateau in layer V pyramidal cells. This plateau potential triggered spike firing in layer V, but not layer II/III pyramidal cells, and was accompanied by recurrent synaptic excitation in layer V. Our results indicate that wide-field imaging of GA bioluminescence is well suited to monitor local and global network activity patterns, involving different mechanisms of intracellular calcium increase, and occurring on various timescales.
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Affiliation(s)
- Ludovic Tricoire
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), INSERM, CNRS, Sorbonne Universités, Paris, France
| | - Estelle Drobac
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), INSERM, CNRS, Sorbonne Universités, Paris, France
| | - Keisuke Tsuzuki
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), INSERM, CNRS, Sorbonne Universités, Paris, France
| | - Thierry Gallopin
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), INSERM, CNRS, Sorbonne Universités, Paris, France
| | - Sandrine Picaud
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), INSERM, CNRS, Sorbonne Universités, Paris, France
| | - Bruno Cauli
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), INSERM, CNRS, Sorbonne Universités, Paris, France
| | - Jean Rossier
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), INSERM, CNRS, Sorbonne Universités, Paris, France
| | - Bertrand Lambolez
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), INSERM, CNRS, Sorbonne Universités, Paris, France
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7
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Yu X, Scott D, Dikici E, Joel S, Deo S, Daunert S. Multiplexing cytokine analysis: towards reducing sample volume needs in clinical diagnostics. Analyst 2019; 144:3250-3259. [DOI: 10.1039/c9an00297a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Our work demonstrates the use of both spatial and temporal resolution to quantify multiple analytes based on bioluminescent labels.
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Affiliation(s)
- Xiaowen Yu
- Department of Biochemistry and Molecular Biology
- Miller School of Medicine
- University of Miami
- Miami
- USA
| | - Daniel Scott
- Department of Chemistry
- University of Kentucky
- Lexington
- USA
| | - Emre Dikici
- Department of Biochemistry and Molecular Biology
- Miller School of Medicine
- University of Miami
- Miami
- USA
| | - Smita Joel
- Department of Biochemistry and Molecular Biology
- Miller School of Medicine
- University of Miami
- Miami
- USA
| | - Sapna Deo
- Department of Biochemistry and Molecular Biology
- Miller School of Medicine
- University of Miami
- Miami
- USA
| | - Sylvia Daunert
- Department of Biochemistry and Molecular Biology
- Miller School of Medicine
- University of Miami
- Miami
- USA
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8
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Mercier D, Tsuchimoto Y, Ohta K, Kazama H. Olfactory Landmark-Based Communication in Interacting Drosophila. Curr Biol 2018; 28:2624-2631.e5. [PMID: 30078566 DOI: 10.1016/j.cub.2018.06.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/31/2018] [Accepted: 06/05/2018] [Indexed: 11/16/2022]
Abstract
To communicate with conspecifics, animals deploy various strategies to release pheromones, chemical signals modulating social and sexual behaviors [1-5]. Importantly, a single pheromone induces different behaviors depending on the context and exposure dynamics [6-8]. Therefore, to comprehend the ethological role of pheromones, it is essential to characterize how neurons in the recipients respond to temporally and spatially fluctuating chemical signals emitted by donors during natural interactions. In Drosophila melanogaster, the male pheromone 11-cis-vaccenyl acetate (cVA) [9] activates specific olfactory receptor neurons (ORNs) [10, 11] to regulate diverse social and sexual behaviors in recipients [12-15]. Physicochemical analyses have identified this chemical on an animal's body [16, 17] and in its local environment [18, 19]. However, because these methods are imprecise in capturing spatiotemporal dynamics, it is poorly understood how individual pheromone cues are released, detected, and interpreted by recipients. Here, we developed a system based on bioluminescence to monitor neural activity in freely interacting Drosophila, and investigated the active detection and perception of the naturally emitted cVA. Unexpectedly, neurons specifically tuned to cVA did not exhibit significant activity during physical interactions between males, and instead responded strongly to olfactory landmarks deposited by males. These landmarks mediated attraction through Or67d receptors and allured both sexes to the marked region. Importantly, the landmarks remained attractive even when a pair of flies was engaged in courtship behavior. In contrast, female deposits did not affect the exploration pattern of either sex. Thus, Drosophila use pheromone marking to remotely signal their sexual identity and to enhance social interactions.
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Affiliation(s)
- Damien Mercier
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama-shi, Saitama 338-8570, Japan
| | - Yoshiko Tsuchimoto
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Kazumi Ohta
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hokto Kazama
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; RIKEN CBS-KAO Collaboration Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
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9
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Chatterjee A, Lamaze A, De J, Mena W, Chélot E, Martin B, Hardin P, Kadener S, Emery P, Rouyer F. Reconfiguration of a Multi-oscillator Network by Light in the Drosophila Circadian Clock. Curr Biol 2018; 28:2007-2017.e4. [PMID: 29910074 PMCID: PMC6039274 DOI: 10.1016/j.cub.2018.04.064] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/28/2018] [Accepted: 04/18/2018] [Indexed: 01/02/2023]
Abstract
The brain clock that drives circadian rhythms of locomotor activity relies on a multi-oscillator neuronal network. In addition to synchronizing the clock with day-night cycles, light also reformats the clock-driven daily activity pattern. How changes in lighting conditions modify the contribution of the different oscillators to remodel the daily activity pattern remains largely unknown. Our data in Drosophila indicate that light readjusts the interactions between oscillators through two different modes. We show that a morning s-LNv > DN1p circuit works in series, whereas two parallel evening circuits are contributed by LNds and other DN1ps. Based on the photic context, the master pacemaker in the s-LNv neurons swaps its enslaved partner-oscillator-LNd in the presence of light or DN1p in the absence of light-to always link up with the most influential phase-determining oscillator. When exposure to light further increases, the light-activated LNd pacemaker becomes independent by decoupling from the s-LNvs. The calibration of coupling by light is layered on a clock-independent network interaction wherein light upregulates the expression of the PDF neuropeptide in the s-LNvs, which inhibits the behavioral output of the DN1p evening oscillator. Thus, light modifies inter-oscillator coupling and clock-independent output-gating to achieve flexibility in the network. It is likely that the light-induced changes in the Drosophila brain circadian network could reveal general principles of adapting to varying environmental cues in any neuronal multi-oscillator system.
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Affiliation(s)
- Abhishek Chatterjee
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Angélique Lamaze
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Joydeep De
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Wilson Mena
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Elisabeth Chélot
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Béatrice Martin
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Paul Hardin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX 77845-3258, USA
| | | | - Patrick Emery
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - François Rouyer
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France.
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10
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Marescotti M, Lagogiannis K, Webb B, Davies RW, Armstrong JD. Monitoring brain activity and behaviour in freely moving Drosophila larvae using bioluminescence. Sci Rep 2018; 8:9246. [PMID: 29915372 PMCID: PMC6006295 DOI: 10.1038/s41598-018-27043-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 05/09/2018] [Indexed: 12/18/2022] Open
Abstract
We present a bioluminescence method, based on the calcium-reporter Aequorin (AEQ), that exploits targeted transgenic expression patterns to identify activity of specific neural groups in the larval Drosophila nervous system. We first refine, for intact but constrained larva, the choice of Aequorin transgene and method of delivery of the co-factor coelenterazine and assay the luminescence signal produced for different neural expression patterns and concentrations of co-factor, using standard photo-counting techniques. We then develop an apparatus that allows simultaneous measurement of this neural signal while video recording the crawling path of an unconstrained animal. The setup also enables delivery and measurement of an olfactory cue (CO2) and we demonstrate the ability to record synchronized changes in Kenyon cell activity and crawling speed caused by the stimulus. Our approach is thus shown to be an effective and affordable method for studying the neural basis of behavior in Drosophila larvae.
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Affiliation(s)
- Manuela Marescotti
- Brainwave-Discovery Ltd., Edinburgh, Scotland, UK. .,The University of Edinburgh, Edinburgh, Scotland, UK.
| | - Konstantinos Lagogiannis
- The University of Edinburgh, Edinburgh, Scotland, UK.,Centre Of Developmental Neuroscience, King's College London, London, UK
| | - Barbara Webb
- The University of Edinburgh, Edinburgh, Scotland, UK
| | - R Wayne Davies
- Brainwave-Discovery Ltd., Edinburgh, Scotland, UK.,The University of Edinburgh, Edinburgh, Scotland, UK
| | - J Douglas Armstrong
- Brainwave-Discovery Ltd., Edinburgh, Scotland, UK.,The University of Edinburgh, Edinburgh, Scotland, UK
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11
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Modulation of neuronal activity in the Drosophila mushroom body by DopEcR, a unique dual receptor for ecdysone and dopamine. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1578-1588. [PMID: 28554773 DOI: 10.1016/j.bbamcr.2017.05.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 05/08/2017] [Accepted: 05/24/2017] [Indexed: 11/22/2022]
Abstract
G-protein-coupled receptors (GPCRs) for steroid hormones mediate unconventional steroid signaling and play a significant role in the rapid actions of steroids in a variety of biological processes, including those in the nervous system. However, the effects of these GPCRs on overall neuronal activity remain largely elusive. Drosophila DopEcR is a GPCR that responds to both ecdysone (the major steroid hormone in insects) and dopamine, regulating multiple second messenger systems. Recent studies have revealed that DopEcR is preferentially expressed in the nervous system and involved in behavioral regulation. Here we utilized the bioluminescent Ca2+-indicator GFP-aequorin to monitor the nicotine-induced Ca2+-response within the mushroom bodies (MB), a higher-order brain center in flies, and examined how DopEcR modulates these Ca2+-dynamics. Our results show that in DopEcR knockdown flies, the nicotine-induced Ca2+-response in the MB was significantly enhanced selectively in the medial lobes. We then reveal that application of DopEcR's ligands, ecdysone and dopamine, had different effects on nicotine-induced Ca2+-responses in the MB: ecdysone enhanced activity in the calyx and cell body region in a DopEcR-dependent manner, whereas dopamine reduced activity in the medial lobes independently of DopEcR. Finally, we show that flies with reduced DopEcR function in the MB display decreased locomotor activity. This behavioral phenotype of DopEcR-deficient flies may be partly due to their enhanced MB activity, since the MB have been implicated in the suppression of locomotor activity. Overall, these data suggest that DopEcR is involved in region-specific modulation of Ca2+ dynamics within the MB, which may play a role in behavioral modulation.
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12
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Bakayan A, Domingo B, Vaquero CF, Peyriéras N, Llopis J. Fluorescent Protein-photoprotein Fusions and Their Applications in Calcium Imaging. Photochem Photobiol 2017; 93:448-465. [PMID: 27925224 DOI: 10.1111/php.12682] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/19/2016] [Indexed: 12/21/2022]
Abstract
Calcium-activated photoproteins, such as aequorin, have been used as luminescent Ca2+ indicators since 1967. After the cloning of aequorin in 1985, microinjection was substituted by its heterologous expression, which opened the way for a widespread use. Molecular fusion of green fluorescent protein (GFP) to aequorin recapitulated the nonradiative energy transfer process that occurs in the jellyfish Aequorea victoria, from which these two proteins were obtained, resulting in an increase of light emission and a shift to longer wavelength. The abundance and location of the chimera are seen by fluorescence, whereas its luminescence reports Ca2+ levels. GFP-aequorin is broadly used in an increasing number of studies, from organelles and cells to intact organisms. By fusing other fluorescent proteins to aequorin, the available luminescence color palette has been expanded for multiplexing assays and for in vivo measurements. In this report, we will attempt to review the various photoproteins available, their reported fusions with fluorescent proteins and their biological applications to image Ca2+ dynamics in organelles, cells, tissue explants and in live organisms.
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Affiliation(s)
- Adil Bakayan
- BioEmergences Unit (CNRS, USR3695), Université Paris-Saclay, Gif-sur-Yvette, France
| | - Beatriz Domingo
- Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Cecilia F Vaquero
- Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Nadine Peyriéras
- BioEmergences Unit (CNRS, USR3695), Université Paris-Saclay, Gif-sur-Yvette, France
| | - Juan Llopis
- Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, Albacete, Spain
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13
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Knafo S, Prendergast A, Thouvenin O, Figueiredo SN, Wyart C. Bioluminescence Monitoring of Neuronal Activity in Freely Moving Zebrafish Larvae. Bio Protoc 2017; 7:e2550. [PMID: 29130058 DOI: 10.21769/bioprotoc.2550] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The proof of concept for bioluminescence monitoring of neural activity in zebrafish with the genetically encoded calcium indicator GFP-aequorin has been previously described (Naumann et al., 2010) but challenges remain. First, bioluminescence signals originating from a single muscle fiber can constitute a major pitfall. Second, bioluminescence signals emanating from neurons only are very small. To improve signals while verifying specificity, we provide an optimized 4 steps protocol achieving: 1) selective expression of a zebrafish codon-optimized GFP-aequorin, 2) efficient soaking of larvae in GFP-aequorin substrate coelenterazine, 3) bioluminescence monitoring of neural activity from motor neurons in free-tailed moving animals performing acoustic escapes and 4) verification of the absence of muscle expression using immunohistochemistry.
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Affiliation(s)
- Steven Knafo
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital de la Pitié-Salpêtrière, Paris, France.,UMRS 1127, INSERM, Paris, France.,UMR 7225, CNRS, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie, Paris, France.,Assistance Publique des Hopitaux de Paris, Paris, France
| | - Andrew Prendergast
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital de la Pitié-Salpêtrière, Paris, France.,UMRS 1127, INSERM, Paris, France.,UMR 7225, CNRS, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie, Paris, France
| | - Olivier Thouvenin
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital de la Pitié-Salpêtrière, Paris, France.,UMRS 1127, INSERM, Paris, France.,UMR 7225, CNRS, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie, Paris, France
| | - Sophie Nunes Figueiredo
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital de la Pitié-Salpêtrière, Paris, France.,UMRS 1127, INSERM, Paris, France.,UMR 7225, CNRS, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie, Paris, France
| | - Claire Wyart
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital de la Pitié-Salpêtrière, Paris, France.,UMRS 1127, INSERM, Paris, France.,UMR 7225, CNRS, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie, Paris, France
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14
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Murmu MS, Martin JR. Interaction between cAMP and intracellular Ca(2+)-signaling pathways during odor-perception and adaptation in Drosophila. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2156-74. [PMID: 27212269 DOI: 10.1016/j.bbamcr.2016.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 05/14/2016] [Accepted: 05/17/2016] [Indexed: 10/21/2022]
Abstract
Binding of an odorant to olfactory receptors triggers cascades of second messenger systems in olfactory receptor neurons (ORNs). Biochemical studies indicate that the transduction mechanism at ORNs is mediated by cyclic adenosine monophosphate (cAMP) and/or inositol,1,4,5-triphosphate (InsP3)-signaling pathways in an odorant-dependent manner. However, the interaction between these two second messenger systems during olfactory perception or adaptation processes is much less understood. Here, we used interfering-RNAi to disrupt the level of cAMP alone or in combination with the InsP3-signaling pathway cellular targets, InsP3 receptor (InsP3R) or ryanodine receptor (RyR) in ORNs, and quantify at ORN axon terminals in the antennal lobe, the odor-induced Ca(2+)-response. In-vivo functional bioluminescence Ca(2+)-imaging indicates that a single 5s application of an odor increased Ca(2+)-transients at ORN axon terminals. However, compared to wild-type controls, the magnitude and duration of ORN Ca(2+)-response was significantly diminished in cAMP-defective flies. In a behavioral assay, perception of odorants was defective in flies with a disrupted cAMP level suggesting that the ability of flies to correctly detect an odor depends on cAMP. Simultaneous disruption of cAMP level and InsP3R or RyR further diminished the magnitude and duration of ORN response to odorants and affected the flies' ability to detect an odor. In conclusion, this study provides functional evidence that cAMP and InsP3-signaling pathways act in synergy to mediate odor processing within the ORN axon terminals, which is encoded in the magnitude and duration of ORN response.
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Affiliation(s)
- Meena Sriti Murmu
- Institut des Neurosciences Paris-Saclay (Neuro-PSI), Team: Imagerie Cérébrale Fonctionnelle et Comportement, UMR-9197, CNRS/Université Paris Sud, 1, Avenue de la Terrasse, Bat. 32/33, 91198 Gif-sur-Yvette Cedex, France.
| | - Jean-René Martin
- Institut des Neurosciences Paris-Saclay (Neuro-PSI), Team: Imagerie Cérébrale Fonctionnelle et Comportement, UMR-9197, CNRS/Université Paris Sud, 1, Avenue de la Terrasse, Bat. 32/33, 91198 Gif-sur-Yvette Cedex, France.
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15
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Lark AR, Kitamoto T, Martin JR. In Vivo Functional Brain Imaging Approach Based on Bioluminescent Calcium Indicator GFP-aequorin. J Vis Exp 2016. [PMID: 26779599 DOI: 10.3791/53705] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Functional in vivo imaging has become a powerful approach to study the function and physiology of brain cells and structures of interest. Recently a new method of Ca(2+)-imaging using the bioluminescent reporter GFP-aequorin (GA) has been developed. This new technique relies on the fusion of the GFP and aequorin genes, producing a molecule capable of binding calcium and - with the addition of its cofactor coelenterazine - emitting bright light that can be monitored through a photon collector. Transgenic lines carrying the GFP-aequorin gene have been generated for both mice and Drosophila. In Drosophila, the GFP-aequorin gene has been placed under the control of the GAL4/UAS binary expression system allowing for targeted expression and imaging within the brain. This method has subsequently been shown to be capable of detecting both inward Ca(2+)-transients and Ca(2+)-released from inner stores. Most importantly it allows for a greater duration in continuous recording, imaging at greater depths within the brain, and recording at high temporal resolutions (up to 8.3 msec). Here we present the basic method for using bioluminescent imaging to record and analyze Ca(2+)-activity within the mushroom bodies, a structure central to learning and memory in the fly brain.
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Affiliation(s)
- Arianna R Lark
- Equipe: Imagerie Cérébrale Fonctionnelle et Comportements (ICFC), Institut des Neurosciences Paris-Saclay (Nero-PSI), UMR-9197, CNRS/Université Paris Sud; Interdisciplinary Program in Neuroscience, Graduate College, University of Iowa
| | - Toshihiro Kitamoto
- Interdisciplinary Program in Neuroscience, Graduate College, University of Iowa; Department of Anesthesia, Carver College of Medicine, University of Iowa
| | - Jean-René Martin
- Equipe: Imagerie Cérébrale Fonctionnelle et Comportements (ICFC), Institut des Neurosciences Paris-Saclay (Nero-PSI), UMR-9197, CNRS/Université Paris Sud;
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16
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Grinstead K, Joel S, Zingg JM, Dikici E, Daunert S. Enabling Aequorin for Biotechnology Applications Through Genetic Engineering. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015:149-179. [PMID: 26475468 DOI: 10.1007/10_2015_336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In recent years, luminescent proteins have been studied for their potential application in a variety of detection systems. Bioluminescent proteins, which do not require an external excitation source, are especially well-suited as reporters in analytical detection. The photoprotein aequorin is a bioluminescent protein that can be engineered for use as a molecular reporter under a wide range of conditions while maintaining its sensitivity. Herein, the characteristics of aequorin as well as the engineering and production of aequorin variants and their impact on signal detection in biological systems are presented. The structural features and activity of aequorin, its benefits as a label for sensing and applications in highly sensitive detection, as well as in gaining insight into biological processes are discussed. Among those, focus has been placed on the highly sensitive calcium detection in vivo, in vitro DNA and small molecule sensing, and development of in vivo imaging technologies. Graphical Abstract.
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Affiliation(s)
- Kristen Grinstead
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Smita Joel
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Jean-Marc Zingg
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Emre Dikici
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Sylvia Daunert
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.
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17
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Knafo S, Wyart C. Optogenetic neuromodulation: New tools for monitoring and breaking neural circuits. Ann Phys Rehabil Med 2015; 58:259-264. [DOI: 10.1016/j.rehab.2015.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 05/10/2015] [Accepted: 05/10/2015] [Indexed: 10/23/2022]
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18
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PKA and cAMP/CNG Channels Independently Regulate the Cholinergic Ca(2+)-Response of Drosophila Mushroom Body Neurons. eNeuro 2015; 2:eN-NWR-0054-14. [PMID: 26464971 PMCID: PMC4596083 DOI: 10.1523/eneuro.0054-14.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 04/03/2015] [Accepted: 04/08/2015] [Indexed: 01/22/2023] Open
Abstract
The mushroom bodies (MBs) are the most prominent structures in adult Drosophila brain. They have been involved in several crucial functions, such as learning and memory, sleep, locomotor activity, and decision making. The mushroom bodies (MBs), one of the main structures in the adult insect brain, play a critical role in olfactory learning and memory. Though historical genes such as dunce and rutabaga, which regulate the level of cAMP, were identified more than 30 years ago, their in vivo effects on cellular and physiological mechanisms and particularly on the Ca2+-responses still remain largely unknown. In this work, performed in Drosophila, we took advantage of in vivo bioluminescence imaging, which allowed real-time monitoring of the entire MBs (both the calyx/cell-bodies and the lobes) simultaneously. We imaged neuronal Ca2+-activity continuously, over a long time period, and characterized the nicotine-evoked Ca2+-response. Using both genetics and pharmacological approaches to interfere with different components of the cAMP signaling pathway, we first show that the Ca2+-response is proportional to the levels of cAMP. Second, we reveal that an acute change in cAMP levels is sufficient to trigger a Ca2+-response. Third, genetic manipulation of protein kinase A (PKA), a direct effector of cAMP, suggests that cAMP also has PKA-independent effects through the cyclic nucleotide-gated Ca2+-channel (CNG). Finally, the disruption of calmodulin, one of the main regulators of the rutabaga adenylate cyclase (AC), yields different effects in the calyx/cell-bodies and in the lobes, suggesting a differential and regionalized regulation of AC. Our results provide insights into the complex Ca2+-response in the MBs, leading to the conclusion that cAMP modulates the Ca2+-responses through both PKA-dependent and -independent mechanisms, the latter through CNG-channels.
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19
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Dugué GP, Tricoire L. [Principles and applications of optogenetics in neuroscience]. Med Sci (Paris) 2015; 31:291-303. [PMID: 25855283 DOI: 10.1051/medsci/20153103015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Numerous achievements in biology have resulted from the evolution of biophotonics, a general term describing the use of light in the study of living systems. Over the last fifteen years, biophotonics has progressively blended with molecular genetics to give rise to optogenetics, a set of techniques enabling the functional study of genetically-defined cellular populations, compartments or processes with optical methods. In neuroscience, optogenetics allows real-time monitoring and control of the activity of specific neuronal populations in a wide range of animal models. This technical breakthrough provides a new level of sophistication in experimental approaches in the field of fundamental neuroscience, significantly enhancing our ability to understand the complexity of neuronal circuits.
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Affiliation(s)
- Guillaume P Dugué
- CNRS UMR 8197, Inserm U1024, IBENS S4.9, 46, rue d'Ulm, 75005 Paris, France
| | - Ludovic Tricoire
- CNRS UMR 8246, Inserm U1130, université Pierre et Marie Curie UM CR119, 9, quai Saint Bernard, 75005 Paris, France
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20
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Ottolini D, Calì T, Brini M. Methods to measure intracellular Ca(2+) fluxes with organelle-targeted aequorin-based probes. Methods Enzymol 2015; 543:21-45. [PMID: 24924126 DOI: 10.1016/b978-0-12-801329-8.00002-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The photoprotein aequorin generates blue light upon binding of Ca(2+) ions. Together with its very low Ca(2+)-buffering capacity and the possibility to add specific targeting sequences, this property has rendered aequorin particularly suitable to monitor Ca(2+) concentrations in specific subcellular compartments. Recently, a new generation of genetically encoded Ca(2+) probes has been developed by fusing Ca(2+)-responsive elements with the green fluorescent protein (GFP). Aequorin has also been employed to this aim, resulting in an aequorin-GFP chimera with the Ca(2+) sensitivity of aequorin and the fluorescent properties of GFP. This setup has actually solved the major limitation of aequorin, for example, its poor ability to emit light, which rendered it inappropriate for the monitoring of Ca(2+) waves at the single-cell level by imaging. In spite of the numerous genetically encoded Ca(2+) indicators that are currently available, aequorin-based probes remain the method of election when an accurate quantification of Ca(2+) levels is required. Here, we describe currently available aequorin variants and their use for monitoring Ca(2+) waves in specific subcellular compartments. Among various applications, this method is relevant for the study of the alterations of Ca(2+) homeostasis that accompany oncogenesis, tumor progression, and response to therapy.
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Affiliation(s)
- Denis Ottolini
- Department of Biology, University of Padova, Padova, Italy
| | - Tito Calì
- Department of Biology, University of Padova, Padova, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy.
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21
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Wyart C, Knafo S. Sensorimotor Integration in the Spinal Cord, from Behaviors to Circuits: New Tools to Close the Loop? BIOLOGICAL AND MEDICAL PHYSICS, BIOMEDICAL ENGINEERING 2015. [DOI: 10.1007/978-3-319-12913-6_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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22
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White-Cooper H. Tissue, cell type and stage-specific ectopic gene expression and RNAi induction in the Drosophila testis. SPERMATOGENESIS 2014; 2:11-22. [PMID: 22553486 PMCID: PMC3341242 DOI: 10.4161/spmg.19088] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The Drosophila testis has numerous advantages for the study of basic cellular processes, as production of sperm requires a highly orchestrated and complex combination of morphological changes and developmentally regulated transitions. Experimental genetics using Drosophila melanogaster has advanced dramatically with the advent of systems for ectopic expression of genetic elements in specific cells. However the genetic tools used in Drosophila research have rarely been generated with the testes in mind, and the utility of relatively few systems has been documented for this tissue. Here I will summarize ectopic expression systems that are known to work for the testis, and provide advice for selection of the most appropriate expression system in specific experimental situations.
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23
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Bioluminescent properties of obelin and aequorin with novel coelenterazine analogues. Anal Bioanal Chem 2014; 406:2695-707. [DOI: 10.1007/s00216-014-7656-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 12/28/2013] [Accepted: 01/23/2014] [Indexed: 10/25/2022]
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24
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Webb SE, Karplus E, Miller AL. Retrospective on the development of aequorin and aequorin-based imaging to visualize changes in intracellular free [Ca2+]. Mol Reprod Dev 2014; 82:563-86. [DOI: 10.1002/mrd.22298] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/26/2013] [Indexed: 12/17/2022]
Affiliation(s)
- Sarah E. Webb
- Division of Life Science and State Key Laboratory of Molecular Neuroscience; The Hong Kong University of Science and Technology; Kowloon Hong Kong
| | | | - Andrew L. Miller
- Division of Life Science and State Key Laboratory of Molecular Neuroscience; The Hong Kong University of Science and Technology; Kowloon Hong Kong
- Marine Biological Laboratory; Woods Hole Massachusetts
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25
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Xiong TC, Ronzier E, Sanchez F, Corratgé-Faillie C, Mazars C, Thibaud JB. Imaging long distance propagating calcium signals in intact plant leaves with the BRET-based GFP-aequorin reporter. FRONTIERS IN PLANT SCIENCE 2014; 5:43. [PMID: 24600459 PMCID: PMC3927637 DOI: 10.3389/fpls.2014.00043] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 01/29/2014] [Indexed: 05/18/2023]
Abstract
Calcium (Ca(2+)) is a second messenger involved in many plant signaling processes. Biotic and abiotic stimuli induce Ca(2+) signals within plant cells, which, when decoded, enable these cells to adapt in response to environmental stresses. Multiple examples of Ca(2+) signals from plants containing the fluorescent yellow cameleon sensor (YC) have contributed to the definition of the Ca(2+) signature in some cell types such as root hairs, pollen tubes and guard cells. YC is, however, of limited use in highly autofluorescent plant tissues, in particular mesophyll cells. Alternatively, the bioluminescent reporter aequorin enables Ca(2+) imaging in the whole plant, including mesophyll cells, but this requires specific devices capable of detecting the low amounts of emitted light. Another type of Ca(2+) sensor, referred to as GFP-aequorin (G5A), has been engineered as a chimeric protein, which combines the two photoactive proteins from the jellyfish Aequorea victoria, the green fluorescent protein (GFP) and the bioluminescent protein aequorin. The Ca(2+)-dependent light-emitting property of G5A is based on a bioluminescence resonance energy transfer (BRET) between aequorin and GFP. G5A has been used for over 10 years for enhanced in vivo detection of Ca(2+) signals in animal tissues. Here, we apply G5A in Arabidopsis and show that G5A greatly improves the imaging of Ca(2+) dynamics in intact plants. We describe a simple method to image Ca(2+) signals in autofluorescent leaves of plants with a cooled charge-coupled device (cooled CCD) camera. We present data demonstrating how plants expressing the G5A probe can be powerful tools for imaging of Ca(2+) signals. It is shown that Ca(2+) signals propagating over long distances can be visualized in intact plant leaves and are visible mainly in the veins.
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Affiliation(s)
- Tou Cheu Xiong
- Biochimie et Physiologie Moléculaire des Plantes, Institut National de la Recherche Agronomique, UMR 386Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, UMR 5004Montpellier, France
- Biochimie et Physiologie Moléculaire des PlantesSupAgro, Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, UM2Montpellier, France
- *Correspondence: Tou Cheu Xiong, Biochimie et Physiologie Moléculaire des Plantes, Institut National de la Recherche Agronomique, UMR 386/Centre National de la Recherche Scientifique, UMR 5004/Montpellier SupAgro/Université Montpellier 2, Campus INRA-SupAgro, Place Pierre Viala, F34060 Montpellier Cedex 2, France e-mail:
| | - Elsa Ronzier
- Biochimie et Physiologie Moléculaire des Plantes, Institut National de la Recherche Agronomique, UMR 386Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, UMR 5004Montpellier, France
- Biochimie et Physiologie Moléculaire des PlantesSupAgro, Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, UM2Montpellier, France
| | - Frédéric Sanchez
- Biochimie et Physiologie Moléculaire des Plantes, Institut National de la Recherche Agronomique, UMR 386Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, UMR 5004Montpellier, France
- Biochimie et Physiologie Moléculaire des PlantesSupAgro, Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, UM2Montpellier, France
| | - Claire Corratgé-Faillie
- Biochimie et Physiologie Moléculaire des Plantes, Institut National de la Recherche Agronomique, UMR 386Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, UMR 5004Montpellier, France
- Biochimie et Physiologie Moléculaire des PlantesSupAgro, Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, UM2Montpellier, France
| | - Christian Mazars
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, UPS, UMR 5546Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, UMR 5546Castanet-Tolosan, France
| | - Jean-Baptiste Thibaud
- Biochimie et Physiologie Moléculaire des Plantes, Institut National de la Recherche Agronomique, UMR 386Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, UMR 5004Montpellier, France
- Biochimie et Physiologie Moléculaire des PlantesSupAgro, Montpellier, France
- Biochimie et Physiologie Moléculaire des Plantes, UM2Montpellier, France
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26
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Tricoire L, Lambolez B. Neuronal network imaging in acute slices using Ca2+ sensitive bioluminescent reporter. Methods Mol Biol 2014; 1098:33-45. [PMID: 24166366 DOI: 10.1007/978-1-62703-718-1_3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Genetically encoded indicators are valuable tools to study intracellular signaling cascades in real time using fluorescent or bioluminescent imaging techniques. Imaging of Ca(2+) indicators is widely used to record transient intracellular Ca(2+) increases associated with bioelectrical activity. The natural bioluminescent Ca(2+) sensor aequorin has been historically the first Ca(2+) indicator used to address biological questions. Aequorin imaging offers several advantages over fluorescent reporters: it is virtually devoid of background signal; it does not require light excitation and interferes little with intracellular processes. Genetically encoded sensors such as aequorin are commonly used in dissociated cultured cells; however it becomes more challenging to express them in differentiated intact specimen such as brain tissue. Here we describe a method to express a GFP-aequorin (GA) fusion protein in pyramidal cells of neocortical acute slices using recombinant Sindbis virus. This technique allows expressing GA in several hundreds of neurons on the same slice and to perform the bioluminescence recording of Ca(2+) transients in single neurons or multiple neurons simultaneously.
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Affiliation(s)
- Ludovic Tricoire
- Neurobiologie des processus adaptatifs, UMR7102, Université Pierre et Marie Curie, Paris, France
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27
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Wright NJD. Evolution of the techniques used in studying associative olfactory learning and memory in adult Drosophila in vivo: a historical and technical perspective. INVERTEBRATE NEUROSCIENCE 2013; 14:1-11. [PMID: 24149895 DOI: 10.1007/s10158-013-0163-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 10/08/2013] [Indexed: 11/25/2022]
Abstract
Drosophila melanogaster behavioral mutants have been isolated in which the ability to form associative olfactory memories has been disrupted primarily by altering cyclic adenosine monophosphate signal transduction. Unfortunately, the small size of the fruit fly and its neurons has made the application of neurobiological techniques typically used to investigate the physiology underlying these behaviors daunting. However, the realization that adult fruit flies could tolerate a window in the head capsule allowing access to the central structures thought to be involved plus the development of genetically expressed reporters of neuronal function has allowed a meteoric expansion of this field over the last decade. This review attempts to summarize the evolution of the techniques involved from the first use of a window to access these brain areas thought to be involved in associative olfactory learning and memory, the mushroom bodies and antennal lobes, to the current refinements which allow both high-resolution multiphoton imaging and patch clamping of identified neurons while applying the stimuli used in the behavioral protocols. This area of research now appears poised to reveal some very exciting mechanisms underlying behavior.
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Affiliation(s)
- Nicholas J D Wright
- Levine College of Health Sciences, Wingate University School of Pharmacy, 515 N. Main Street, Wingate, NC, 28174, USA,
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28
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Marblestone AH, Zamft BM, Maguire YG, Shapiro MG, Cybulski TR, Glaser JI, Amodei D, Stranges PB, Kalhor R, Dalrymple DA, Seo D, Alon E, Maharbiz MM, Carmena JM, Rabaey JM, Boyden ES, Church GM, Kording KP. Physical principles for scalable neural recording. Front Comput Neurosci 2013; 7:137. [PMID: 24187539 PMCID: PMC3807567 DOI: 10.3389/fncom.2013.00137] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 09/23/2013] [Indexed: 12/20/2022] Open
Abstract
Simultaneously measuring the activities of all neurons in a mammalian brain at millisecond resolution is a challenge beyond the limits of existing techniques in neuroscience. Entirely new approaches may be required, motivating an analysis of the fundamental physical constraints on the problem. We outline the physical principles governing brain activity mapping using optical, electrical, magnetic resonance, and molecular modalities of neural recording. Focusing on the mouse brain, we analyze the scalability of each method, concentrating on the limitations imposed by spatiotemporal resolution, energy dissipation, and volume displacement. Based on this analysis, all existing approaches require orders of magnitude improvement in key parameters. Electrical recording is limited by the low multiplexing capacity of electrodes and their lack of intrinsic spatial resolution, optical methods are constrained by the scattering of visible light in brain tissue, magnetic resonance is hindered by the diffusion and relaxation timescales of water protons, and the implementation of molecular recording is complicated by the stochastic kinetics of enzymes. Understanding the physical limits of brain activity mapping may provide insight into opportunities for novel solutions. For example, unconventional methods for delivering electrodes may enable unprecedented numbers of recording sites, embedded optical devices could allow optical detectors to be placed within a few scattering lengths of the measured neurons, and new classes of molecularly engineered sensors might obviate cumbersome hardware architectures. We also study the physics of powering and communicating with microscale devices embedded in brain tissue and find that, while radio-frequency electromagnetic data transmission suffers from a severe power-bandwidth tradeoff, communication via infrared light or ultrasound may allow high data rates due to the possibility of spatial multiplexing. The use of embedded local recording and wireless data transmission would only be viable, however, given major improvements to the power efficiency of microelectronic devices.
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Affiliation(s)
- Adam H. Marblestone
- Biophysics Program, Harvard UniversityBoston, MA, USA
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBoston, MA, USA
| | | | - Yael G. Maguire
- Department of Genetics, Harvard Medical SchoolBoston, MA, USA
- Plum Labs LLCCambridge, MA, USA
| | - Mikhail G. Shapiro
- Division of Chemistry and Chemical Engineering, California Institute of TechnologyPasadena, CA, USA
| | | | - Joshua I. Glaser
- Interdepartmental Neuroscience Program, Northwestern UniversityChicago, IL, USA
| | - Dario Amodei
- Department of Radiology, Stanford UniversityPalo Alto, CA, USA
| | | | - Reza Kalhor
- Department of Genetics, Harvard Medical SchoolBoston, MA, USA
| | - David A. Dalrymple
- Biophysics Program, Harvard UniversityBoston, MA, USA
- NemaloadSan Francisco, CA, USA
- Media Laboratory, Massachusetts Institute of TechnologyCambridge, MA, USA
| | - Dongjin Seo
- Department of Electrical Engineering and Computer Sciences, University of California at BerkeleyBerkeley, CA, USA
| | - Elad Alon
- Department of Electrical Engineering and Computer Sciences, University of California at BerkeleyBerkeley, CA, USA
| | - Michel M. Maharbiz
- Department of Electrical Engineering and Computer Sciences, University of California at BerkeleyBerkeley, CA, USA
| | - Jose M. Carmena
- Department of Electrical Engineering and Computer Sciences, University of California at BerkeleyBerkeley, CA, USA
- Helen Wills Neuroscience Institute, University of California at BerkeleyBerkeley, CA, USA
| | - Jan M. Rabaey
- Department of Electrical Engineering and Computer Sciences, University of California at BerkeleyBerkeley, CA, USA
| | - Edward S. Boyden
- Media Laboratory, Massachusetts Institute of TechnologyCambridge, MA, USA
- Departments of Brain and Cognitive Sciences and Biological Engineering, Massachusetts Institute of TechnologyCambridge, MA, USA
| | - George M. Church
- Biophysics Program, Harvard UniversityBoston, MA, USA
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBoston, MA, USA
- Department of Genetics, Harvard Medical SchoolBoston, MA, USA
| | - Konrad P. Kording
- Departments of Physical Medicine and Rehabilitation and of Physiology, Northwestern University Feinberg School of MedicineChicago, IL, USA
- Sensory Motor Performance Program, The Rehabilitation Institute of ChicagoChicago, IL, USA
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Cavaliere S, Malik BR, Hodge JJL. KCNQ channels regulate age-related memory impairment. PLoS One 2013; 8:e62445. [PMID: 23638087 PMCID: PMC3640075 DOI: 10.1371/journal.pone.0062445] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 03/21/2013] [Indexed: 12/22/2022] Open
Abstract
In humans KCNQ2/3 heteromeric channels form an M-current that acts as a brake on neuronal excitability, with mutations causing a form of epilepsy. The M-current has been shown to be a key regulator of neuronal plasticity underlying associative memory and ethanol response in mammals. Previous work has shown that many of the molecules and plasticity mechanisms underlying changes in alcohol behaviour and addiction are shared with those of memory. We show that the single KCNQ channel in Drosophila (dKCNQ) when mutated show decrements in associative short- and long-term memory, with KCNQ function in the mushroom body α/βneurons being required for short-term memory. Ethanol disrupts memory in wildtype flies, but not in a KCNQ null mutant background suggesting KCNQ maybe a direct target of ethanol, the blockade of which interferes with the plasticity machinery required for memory formation. We show that as in humans, Drosophila display age-related memory impairment with the KCNQ mutant memory defect mimicking the effect of age on memory. Expression of KCNQ normally decreases in aging brains and KCNQ overexpression in the mushroom body neurons of KCNQ mutants restores age-related memory impairment. Therefore KCNQ is a central plasticity molecule that regulates age dependent memory impairment.
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Affiliation(s)
- Sonia Cavaliere
- School of Physiology and Pharmacology, University of Bristol, Bristol, Avon, United Kingdom
| | - Bilal R. Malik
- School of Physiology and Pharmacology, University of Bristol, Bristol, Avon, United Kingdom
| | - James J. L. Hodge
- School of Physiology and Pharmacology, University of Bristol, Bristol, Avon, United Kingdom
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Berglund K, Birkner E, Augustine GJ, Hochgeschwender U. Light-emitting channelrhodopsins for combined optogenetic and chemical-genetic control of neurons. PLoS One 2013; 8:e59759. [PMID: 23544095 PMCID: PMC3609769 DOI: 10.1371/journal.pone.0059759] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/18/2013] [Indexed: 01/10/2023] Open
Abstract
Manipulation of neuronal activity through genetically targeted actuator molecules is a powerful approach for studying information flow in the brain. In these approaches the genetically targeted component, a receptor or a channel, is activated either by a small molecule (chemical genetics) or by light from a physical source (optogenetics). We developed a hybrid technology that allows control of the same neurons by both optogenetic and chemical genetic means. The approach is based on engineered chimeric fusions of a light-generating protein (luciferase) to a light-activated ion channel (channelrhodopsin). Ionic currents then can be activated by bioluminescence upon activation of luciferase by its substrate, coelenterazine (CTZ), as well as by external light. In cell lines, expression of the fusion of Gaussia luciferase to Channelrhodopsin-2 yielded photocurrents in response to CTZ. Larger photocurrents were produced by fusing the luciferase to Volvox Channelrhodopsin-1. This version allowed chemical modulation of neuronal activity when expressed in cultured neurons: CTZ treatment shifted neuronal responses to injected currents and sensitized neurons to fire action potentials in response to subthreshold synaptic inputs. These luminescent channelrhodopsins--or luminopsins--preserve the advantages of light-activated ion channels, while extending their capabilities. Our proof-of-principle results suggest that this novel class of tools can be improved and extended in numerous ways.
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Affiliation(s)
- Ken Berglund
- Department of Neurobiology, Duke University, Durham, North Carolina, United States of America
| | - Elisabeth Birkner
- Department of Neurobiology, Duke University, Durham, North Carolina, United States of America
- NeuroTransgenic Laboratory, Duke University, Durham, North Carolina, United States of America
| | - George J. Augustine
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore, Singapore
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Ute Hochgeschwender
- Department of Neurobiology, Duke University, Durham, North Carolina, United States of America
- NeuroTransgenic Laboratory, Duke University, Durham, North Carolina, United States of America
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Cabrero P, Richmond L, Nitabach M, Davies SA, Dow JAT. A biogenic amine and a neuropeptide act identically: tyramine signals through calcium in Drosophila tubule stellate cells. Proc Biol Sci 2013; 280:20122943. [PMID: 23446525 PMCID: PMC3619477 DOI: 10.1098/rspb.2012.2943] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Insect osmoregulation is subject to highly sophisticated endocrine control. In Drosophila, both Drosophila kinin and tyramine act on the Malpighian (renal) tubule stellate cell to activate chloride shunt conductance, and so increase the fluid production rate. Drosophila kinin is known to act through intracellular calcium, but the mode of action of tyramine is not known. Here, we used a transgenically encoded GFP::apoaequorin translational fusion, targeted to either principal or stellate cells under GAL4/UAS control, to demonstrate that tyramine indeed acts to raise calcium in stellate, but not principal cells. Furthermore, the EC(50) tyramine concentration for half-maximal activation of the intracellular calcium signal is the same as that calculated from previously published data on tyramine-induced increase in chloride flux. In addition, tyramine signalling to calcium is markedly reduced in mutants of NorpA (a phospholipase C) and itpr, the inositol trisphosphate receptor gene, which we have previously shown to be necessary for Drosophila kinin signalling. Therefore, tyramine and Drosophila kinin signals converge on phospholipase C, and thence on intracellular calcium; and both act to increase chloride shunt conductance by signalling through itpr. To test this model, we co-applied tyramine and Drosophila kinin, and showed that the calcium signals were neither additive nor synergistic. The two signalling pathways thus represent parallel, independent mechanisms for distinct tissues (nervous and epithelial) to control the same aspect of renal function.
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Affiliation(s)
- Pablo Cabrero
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Minocci D, Carbognin E, Murmu MS, Martin JR. In vivo functional calcium imaging of induced or spontaneous activity in the fly brain using a GFP-apoaequorin-based bioluminescent approach. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:1632-40. [PMID: 23287020 DOI: 10.1016/j.bbamcr.2012.12.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/14/2012] [Accepted: 12/19/2012] [Indexed: 11/29/2022]
Abstract
Different optical imaging techniques have been developed to study neuronal activity with the goal of deciphering the neural code underlying neurophysiological functions. Because of several constraints inherent in these techniques as well as difficulties interpreting the results, the majority of these studies have been dedicated more to sensory modalities than to the spontaneous activity of the central brain. Recently, a novel bioluminescence approach based on GFP-aequorin (GA) (GFP: Green fluorescent Protein), has been developed, allowing us to functionally record in-vivo neuronal activity. Taking advantage of the particular characteristics of GA, which does not require light excitation, we report that we can record induced and/or the spontaneous Ca(2+)-activity continuously over long periods. Targeting GA to the mushrooms-bodies (MBs), a structure implicated in learning/memory and sleep, we have shown that GA is sensitive enough to detect odor-induced Ca(2+)-activity in Kenyon cells (KCs). It has been possible to reveal two particular peaks of spontaneous activity during overnight recording in the MBs. Other peaks of spontaneous activity have been recorded in flies expressing GA pan-neurally. Similarly, expression in the glial cells has revealed that these cells exhibit a cell-autonomous Ca(2+)-activity. These results demonstrate that bioluminescence imaging is a useful tool for studying Ca(2+)-activity in neuronal and/or glial cells and for functional mapping of the neurophysiological processes in the fly brain. These findings provide a framework for investigating the biological meaning of spontaneous neuronal activity. This article is part of a Special Issue entitled: 12th European Symposium on Calcium.
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Affiliation(s)
- Daiana Minocci
- Imagerie Cérébrale Fonctionnelle et Comportements, Neurobiologie et Développement, Gif-sur-Yvette, France
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Ueno K, Naganos S, Hirano Y, Horiuchi J, Saitoe M. Long-term enhancement of synaptic transmission between antennal lobe and mushroom body in cultured Drosophila brain. J Physiol 2012; 591:287-302. [PMID: 23027817 DOI: 10.1113/jphysiol.2012.242909] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In Drosophila, the mushroom body (MB) is a critical brain structure for olfactory associative learning. During aversive conditioning, the MBs are thought to associate odour signals, conveyed by projection neurons (PNs) from the antennal lobe (AL), with shock signals conveyed through ascending fibres of the ventral nerve cord (AFV). Although synaptic transmission between AL and MB might play a crucial role for olfactory associative learning, its physiological properties have not been examined directly. Using a cultured Drosophila brain expressing a Ca(2+) indicator in the MBs, we investigated synaptic transmission and plasticity at the AL-MB synapse. Following stimulation with a glass micro-electrode, AL-induced Ca(2+) responses in the MBs were mediated through Drosophila nicotinic acetylcholine receptors (dnAChRs), while AFV-induced Ca(2+) responses were mediated through Drosophila NMDA receptors (dNRs). AL-MB synaptic transmission was enhanced more than 2 h after the simultaneous 'associative-stimulation' of AL and AFV, and such long-term enhancement (LTE) was specifically formed at the AL-MB synapses but not at the AFV-MB synapses. AL-MB LTE was not induced by intense stimulation of the AL alone, and the LTE decays within 60 min after subsequent repetitive AL stimulation. These phenotypes of associativity, input specificity and persistence of AL-MB LTE are highly reminiscent of olfactory memory. Furthermore, similar to olfactory aversive memory, AL-MB LTE formation required activation of the Drosophila D1 dopamine receptor, DopR, along with dnAChR and dNR during associative stimulations. These physiological and genetic analogies indicate that AL-MB LTE might be a relevant cellular model for olfactory memory.
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Affiliation(s)
- Kohei Ueno
- Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 1568506, Japan.
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Abstract
Bioluminescence imaging of live cells has recently been recognized as an important alternative to fluorescence imaging. Fluorescent probes are much brighter than bioluminescent probes (luciferase enzymes) and, therefore, provide much better spatial and temporal resolution and much better contrast for delineating cell structure. However, with bioluminescence imaging there is virtually no background or toxicity. As a result, bioluminescence can be superior to fluorescence for detecting and quantifying molecules and their interactions in living cells, particularly in long-term studies. Structurally diverse luciferases from beetle and marine species have been used for a wide variety of applications, including tracking cells in vivo, detecting protein-protein interactions, measuring levels of calcium and other signaling molecules, detecting protease activity, and reporting circadian clock gene expression. Such applications can be optimized by the use of brighter and variously colored luciferases, brighter microscope optics, and ultrasensitive, low-noise cameras. This article presents a review of how bioluminescence differs from fluorescence, its applications to cellular imaging, and available probes, optics, and detectors. It also gives practical suggestions for optimal bioluminescence imaging of single cells.
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35
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Using translational enhancers to increase transgene expression in Drosophila. Proc Natl Acad Sci U S A 2012; 109:6626-31. [PMID: 22493255 DOI: 10.1073/pnas.1204520109] [Citation(s) in RCA: 238] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability to specify the expression levels of exogenous genes inserted in the genomes of transgenic animals is critical for the success of a wide variety of experimental manipulations. Protein production can be regulated at the level of transcription, mRNA transport, mRNA half-life, or translation efficiency. In this report, we show that several well-characterized sequence elements derived from plant and insect viruses are able to function in Drosophila to increase the apparent translational efficiency of mRNAs by as much as 20-fold. These increases render expression levels sufficient for genetic constructs previously requiring multiple copies to be effective in single copy, including constructs expressing the temperature-sensitive inactivator of neuronal function Shibire(ts1), and for the use of cytoplasmic GFP to image the fine processes of neurons.
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Hara-Miyauchi C, Tsuji O, Hanyu A, Okada S, Yasuda A, Fukano T, Akazawa C, Nakamura M, Imamura T, Matsuzaki Y, Okano HJ, Miyawaki A, Okano H. Bioluminescent system for dynamic imaging of cell and animal behavior. Biochem Biophys Res Commun 2012; 419:188-93. [PMID: 22333570 DOI: 10.1016/j.bbrc.2012.01.141] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Accepted: 01/30/2012] [Indexed: 01/23/2023]
Abstract
The current utility of bioluminescence imaging is constrained by a low photon yield that limits temporal sensitivity. Here, we describe an imaging method that uses a chemiluminescent/fluorescent protein, ffLuc-cp156, which consists of a yellow variant of Aequorea GFP and firefly luciferase. We report an improvement in photon yield by over three orders of magnitude over current bioluminescent systems. We imaged cellular movement at high resolution including neuronal growth cones and microglial cell protrusions. Transgenic ffLuc-cp156 mice enabled video-rate bioluminescence imaging of freely moving animals, which may provide a reliable assay for drug distribution in behaving animals for pre-clinical studies.
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Russell JT. Imaging calcium signals in vivo: a powerful tool in physiology and pharmacology. Br J Pharmacol 2012; 163:1605-25. [PMID: 20718728 DOI: 10.1111/j.1476-5381.2010.00988.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The design and engineering of organic fluorescent Ca(2+) indicators approximately 30 years ago opened the door for imaging cellular Ca(2+) signals with a high degree of temporal and spatial resolution. Over this time, Ca(2+) imaging has revolutionized our approaches for tissue-level spatiotemporal analysis of functional organization and has matured into a powerful tool for in situ imaging of cellular activity in the living animal. In vivo Ca(2+) imaging with temporal resolution at the millisecond range and spatial resolution at micrometer range has been achieved through novel designs of Ca(2+) sensors, development of modern microscopes and powerful imaging techniques such as two-photon microscopy. Imaging Ca(2+) signals in ensembles of cells within tissue in 3D allows for analysis of integrated cellular function, which, in the case of the brain, enables recording activity patterns in local circuits. The recent development of miniaturized compact, fibre-optic-based, mechanically flexible microendoscopes capable of two-photon microscopy opens the door for imaging activity in awake, behaving animals. This development is poised to open a new chapter in physiological experiments and for pharmacological approaches in the development of novel therapies.
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Affiliation(s)
- James T Russell
- Section on Cell Biology and Signal Transduction, Laboratory of Cellular and Molecular Neurophysiology, National Institute of Child Health and Human Development/NIH, 49 Convent Drive, Bethesda, MD 20892-4480, USA.
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Strutz A, Völler T, Riemensperger T, Fiala A, Sachse S. Calcium Imaging of Neural Activity in the Olfactory System of Drosophila. GENETICALLY ENCODED FUNCTIONAL INDICATORS 2012. [DOI: 10.1007/978-1-62703-014-4_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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40
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Webb SE, Miller AL. Aequorin-based genetic approaches to visualize Ca2+ signaling in developing animal systems. Biochim Biophys Acta Gen Subj 2011; 1820:1160-8. [PMID: 22198462 DOI: 10.1016/j.bbagen.2011.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 12/07/2011] [Accepted: 12/08/2011] [Indexed: 12/17/2022]
Abstract
BACKGROUND In recent years, as our understanding of the various roles played by Ca2+ signaling in development and differentiation has expanded, the challenge of imaging Ca2+ dynamics within living cells, tissues, and whole animal systems has been extended to include specific signaling activity in organelles and non-membrane bound sub-cellular domains. SCOPE OF REVIEW In this review we outline how recent advances in genetics and molecular biology have contributed to improving and developing current bioluminescence-based Ca2+ imaging techniques. Reporters can now be targeted to specific cell types, or indeed organelles or domains within a particular cell. MAJOR CONCLUSIONS These advances have contributed to our current understanding of the specificity and heterogeneity of developmental Ca2+ signaling. The improvement in the spatial resolution that results from specifically targeting a Ca2+ reporter has helped to reveal how a ubiquitous signaling messenger like Ca2+ can regulate coincidental but different signaling events within an individual cell; a Ca2+ signaling paradox that until now has been hard to explain. GENERAL SIGNIFICANCE Techniques used to target specific reporters via genetic means will have applications beyond those of the Ca2+ signaling field, and these will, therefore, make a significant contribution in extending our understanding of the signaling networks that regulate animal development. This article is part of a Special Issue entitled Biochemical, biophysical and genetic approaches to intracellular calcium signalling.
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Affiliation(s)
- Sarah E Webb
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong.
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41
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Krucker T, Sandanaraj BS. Optical imaging for the new grammar of drug discovery. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:4651-4665. [PMID: 22006912 DOI: 10.1098/rsta.2011.0300] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Optical technologies used in biomedical research have undergone tremendous development in the last decade and enabled important insight into biochemical, cellular and physiological phenomena at the microscopic and macroscopic level. Historically in drug discovery, to increase throughput in screening, or increase efficiency through automation of image acquisition and analysis in pathology, efforts in imaging were focused on the reengineering of established microscopy solutions. However, with the emergence of the new grammar for drug discovery, other requirements and expectations have created unique opportunities for optical imaging. The new grammar of drug discovery provides rules for translating the wealth of genomic and proteomic information into targeted medicines with a focus on complex interactions of proteins. This paradigm shift requires highly specific and quantitative imaging at the molecular level with tools that can be used in cellular assays, animals and finally translated into patients. The development of fluorescent targeted and activatable 'smart' probes, fluorescent proteins and new reporter gene systems as functional and dynamic markers of molecular events in vitro and in vivo is therefore playing a pivotal role. An enabling optical imaging platform will combine optical hardware refinement with a strong emphasis on creating and validating highly specific chemical and biological tools.
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Affiliation(s)
- Thomas Krucker
- Global Imaging Group, Novartis Institutes for BioMedical Research, Cambridge, MA 02139, USA.
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Murmu MS, Stinnakre J, Réal E, Martin JR. Calcium-stores mediate adaptation in axon terminals of olfactory receptor neurons in Drosophila. BMC Neurosci 2011; 12:105. [PMID: 22024464 PMCID: PMC3226658 DOI: 10.1186/1471-2202-12-105] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 10/24/2011] [Indexed: 11/30/2022] Open
Abstract
Background In vertebrates and invertebrates, sensory neurons adapt to variable ambient conditions, such as the duration or repetition of a stimulus, a physiological mechanism considered as a simple form of non-associative learning and neuronal plasticity. Although various signaling pathways, as cAMP, cGMP, and the inositol 1,4,5-triphosphate receptor (InsP3R) play a role in adaptation, their precise mechanisms of action at the cellular level remain incompletely understood. Recently, in Drosophila, we reported that odor-induced Ca2+-response in axon terminals of olfactory receptor neurons (ORNs) is related to odor duration. In particular, a relatively long odor stimulus (such as 5 s) triggers the induction of a second component involving intracellular Ca2+-stores. Results We used a recently developed in-vivo bioluminescence imaging approach to quantify the odor-induced Ca2+-activity in the axon terminals of ORNs. Using either a genetic approach to target specific RNAs, or a pharmacological approach, we show that the second component, relying on the intracellular Ca2+-stores, is responsible for the adaptation to repetitive stimuli. In the antennal lobes (a region analogous to the vertebrate olfactory bulb) ORNs make synaptic contacts with second-order neurons, the projection neurons (PNs). These synapses are modulated by GABA, through either GABAergic local interneurons (LNs) and/or some GABAergic PNs. Application of GABAergic receptor antagonists, both GABAA or GABAB, abolishes the adaptation, while RNAi targeting the GABABR (a metabotropic receptor) within the ORNs, blocks the Ca2+-store dependent component, and consequently disrupts the adaptation. These results indicate that GABA exerts a feedback control. Finally, at the behavioral level, using an olfactory test, genetically impairing the GABABR or its signaling pathway specifically in the ORNs disrupts olfactory adapted behavior. Conclusion Taken together, our results indicate that a relatively long lasting form of adaptation occurs within the axon terminals of the ORNs in the antennal lobes, which depends on intracellular Ca2+-stores, attributable to a positive feedback through the GABAergic synapses.
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Affiliation(s)
- Meena S Murmu
- Imagerie Cérébrale Fonctionnelle et Comportements, Neurobiologie et Développement, CNRS, UPR-3294, 1 Avenue de la Terrasse, Gif-sur-Yvette Cedex, France
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43
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Venken KJ, Simpson JH, Bellen HJ. Genetic manipulation of genes and cells in the nervous system of the fruit fly. Neuron 2011; 72:202-30. [PMID: 22017985 PMCID: PMC3232021 DOI: 10.1016/j.neuron.2011.09.021] [Citation(s) in RCA: 293] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2011] [Indexed: 12/26/2022]
Abstract
Research in the fruit fly Drosophila melanogaster has led to insights in neural development, axon guidance, ion channel function, synaptic transmission, learning and memory, diurnal rhythmicity, and neural disease that have had broad implications for neuroscience. Drosophila is currently the eukaryotic model organism that permits the most sophisticated in vivo manipulations to address the function of neurons and neuronally expressed genes. Here, we summarize many of the techniques that help assess the role of specific neurons by labeling, removing, or altering their activity. We also survey genetic manipulations to identify and characterize neural genes by mutation, overexpression, and protein labeling. Here, we attempt to acquaint the reader with available options and contexts to apply these methods.
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Affiliation(s)
- Koen J.T. Venken
- Department of Molecular and Human Genetics, Neurological Research Institute, Baylor College of Medicine, Houston, Texas, 77030
| | - Julie H. Simpson
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, 20147
| | - Hugo J. Bellen
- Department of Molecular and Human Genetics, Neurological Research Institute, Baylor College of Medicine, Houston, Texas, 77030
- Program in Developmental Biology, Department of Neuroscience, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, 77030
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Affiliation(s)
- David M Raizen
- Department of Neurology, University of Pennsylvania School of Medicine
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45
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Inoshita T, Martin JR, Marion-Poll F, Ferveur JF. Peripheral, central and behavioral responses to the cuticular pheromone bouquet in Drosophila melanogaster males. PLoS One 2011; 6:e19770. [PMID: 21625481 PMCID: PMC3098836 DOI: 10.1371/journal.pone.0019770] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 04/04/2011] [Indexed: 11/18/2022] Open
Abstract
Pheromonal communication is crucial with regard to mate choice in many animals including insects. Drosophila melanogaster flies produce a pheromonal bouquet with many cuticular hydrocarbons some of which diverge between the sexes and differently affect male courtship behavior. Cuticular pheromones have a relatively high weight and are thought to be -- mostly but not only -- detected by gustatory contact. However, the response of the peripheral and central gustatory systems to these substances remains poorly explored. We measured the effect induced by pheromonal cuticular mixtures on (i) the electrophysiological response of peripheral gustatory receptor neurons, (ii) the calcium variation in brain centers receiving these gustatory inputs and (iii) the behavioral reaction induced in control males and in mutant desat1 males, which show abnormal pheromone production and perception. While male and female pheromones induced inhibitory-like effects on taste receptor neurons, the contact of male pheromones on male fore-tarsi elicits a long-lasting response of higher intensity in the dedicated gustatory brain center. We found that the behavior of control males was more strongly inhibited by male pheromones than by female pheromones, but this difference disappeared in anosmic males. Mutant desat1 males showed an increased sensitivity of their peripheral gustatory neurons to contact pheromones and a behavioral incapacity to discriminate sex pheromones. Together our data indicate that cuticular hydrocarbons induce long-lasting inhibitory effects on the relevant taste pathway which may interact with the olfactory pathway to modulate pheromonal perception.
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Affiliation(s)
- Tsuyoshi Inoshita
- Centre des Sciences du Goût et de l'Alimentation, Unité Mixte de Recherche-6265 Centre National de la Recherche Scientifique, Unité Mixte de Recherche-1324 Institut National de la Recherche Agronomique, Université de Bourgogne, Dijon, France
| | - Jean-René Martin
- Laboratoire de Neurobiologie and Développement, Unité Propre de Recherche 3294, Centre National de la Recherche Scientifique - Institut de Neurobiologie Alfred Fessard, Gif-sur-Yvette, France
| | - Frédéric Marion-Poll
- Physiologie de l'Insecte: Signalisation et Communication, Unité Mixte de Recherche-1272 Institut National de la Recherche Agronomique/Université Pierre et Marie Curie, Versailles, France
- AgroParisTech, Département Science de la Vie et Santé, Paris, France
| | - Jean-François Ferveur
- Centre des Sciences du Goût et de l'Alimentation, Unité Mixte de Recherche-6265 Centre National de la Recherche Scientifique, Unité Mixte de Recherche-1324 Institut National de la Recherche Agronomique, Université de Bourgogne, Dijon, France
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Miranda MI, González-Cedillo FJ, Díaz-Muñoz M. Intracellular calcium chelation and pharmacological SERCA inhibition of Ca2+ pump in the insular cortex differentially affect taste aversive memory formation and retrieval. Neurobiol Learn Mem 2011; 96:192-8. [PMID: 21524709 DOI: 10.1016/j.nlm.2011.04.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 03/12/2011] [Accepted: 04/11/2011] [Indexed: 12/23/2022]
Abstract
Variation in intracellular calcium concentration regulates the induction of long-term synaptic plasticity and is associated with a variety of memory/retrieval and learning paradigms. Accordingly, impaired calcium mobilization from internal deposits affects synaptic plasticity and cognition in the aged brain. During taste memory formation several proteins are modulated directly or indirectly by calcium, and recent evidence suggests the importance of calcium buffering and the role of intracellular calcium deposits during cognitive processes. Thus, the main goal of this research was to study the consequence of hampering changes in cytoplasmic calcium and inhibiting SERCA activity by BAPTA-AM and thapsigargin treatments, respectively, in the insular cortex during different stages of taste memory formation. Using conditioned taste aversion (CTA), we found differential effects of BAPTA-AM and thapsigargin infusions before and after gustatory stimulation, as well as during taste aversive memory consolidation; BAPTA-AM, but not thapsigargin, attenuates acquisition and/or consolidation of CTA, but neither compound affects taste aversive memory retrieval. These results point to the importance of intracellular calcium dynamics in the insular cortex during different stages of taste aversive memory formation.
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Affiliation(s)
- María Isabel Miranda
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 96230, México.
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47
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Murmu MS, Stinnakre J, Martin JR. Presynaptic Ca2+ stores contribute to odor-induced responses in Drosophila olfactory receptor neurons. ACTA ACUST UNITED AC 2011; 213:4163-73. [PMID: 21112997 DOI: 10.1242/jeb.046474] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In both vertebrates and invertebrates, olfactory receptor neurons (ORNs) respond to several odors. They also adapt to stimulus variations, and this is considered to be a simple form of non-associative learning and neuronal plasticity. Different mechanisms have been described to support neuronal and/or synaptic plasticity. For example in vertebrates, presynaptic Ca(2+) stores relying on either the ryanodine receptor (RyR) or the inositol (1,4,5)-trisphosphate receptor (InsP(3)R) have been reported to participate in synaptic transmission, in hippocampal pyramidal neurons, and in basket cell-Purkinje cell synapses. However, in invertebrates, especially in sensory neurons such as ORNs, similar mechanisms have not yet been detected. In this study, using Drosophila and taking advantage of an in vivo bioluminescence Ca(2+)-imaging technique in combination with genetic and pharmacological tools, first we show that the GFP-aequorin Ca(2+) sensor is sensitive enough to detect odor-induced responses of various durations. Second, we show that for a relatively long (5 s) odor application, odor-induced Ca(2+) responses occurring in the axon terminals of ORNs involve intracellular Ca(2+) stores. This response is decreased by specifically targeting InsP(3)R or RyR by RNAi, or application of the specific blockers thapsigargin or ryanodine, suggesting that Ca(2+) stores serve to amplify the presynaptic signal. Furthermore, we show that disrupting the intracellular Ca(2+) stores in the ORNs has functional consequences since InsP(3)R- or RyR-RNAi expressing flies were defective in olfactory behavior. Altogether, our results indicate that for long odor applications in Drosophila, the olfactory response depends on intracellular Ca(2+) stores within the axon terminals of the ORNs.
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Affiliation(s)
- Meena Sriti Murmu
- Imagerie Cérébrale Fonctionnelle et Comportements, Neurobiologie et Developpement (N&D), CNRS, UPR-3294, 1 Avenue de la Terrasse, Bâtiment 32, 91198, Gif-sur-Yvette, France
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48
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Brembs B. Towards a scientific concept of free will as a biological trait: spontaneous actions and decision-making in invertebrates. Proc Biol Sci 2011; 278:930-9. [PMID: 21159679 PMCID: PMC3049057 DOI: 10.1098/rspb.2010.2325] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 11/25/2010] [Indexed: 11/12/2022] Open
Abstract
Until the advent of modern neuroscience, free will used to be a theological and a metaphysical concept, debated with little reference to brain function. Today, with ever increasing understanding of neurons, circuits and cognition, this concept has become outdated and any metaphysical account of free will is rightfully rejected. The consequence is not, however, that we become mindless automata responding predictably to external stimuli. On the contrary, accumulating evidence also from brains much smaller than ours points towards a general organization of brain function that incorporates flexible decision-making on the basis of complex computations negotiating internal and external processing. The adaptive value of such an organization consists of being unpredictable for competitors, prey or predators, as well as being able to explore the hidden resource deterministic automats would never find. At the same time, this organization allows all animals to respond efficiently with tried-and-tested behaviours to predictable and reliable stimuli. As has been the case so many times in the history of neuroscience, invertebrate model systems are spearheading these research efforts. This comparatively recent evidence indicates that one common ability of most if not all brains is to choose among different behavioural options even in the absence of differences in the environment and perform genuinely novel acts. Therefore, it seems a reasonable effort for any neurobiologist to join and support a rather illustrious list of scholars who are trying to wrestle the term 'free will' from its metaphysical ancestry. The goal is to arrive at a scientific concept of free will, starting from these recently discovered processes with a strong emphasis on the neurobiological mechanisms underlying them.
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Affiliation(s)
- Björn Brembs
- Freie Universität Berlin, Institute for Biology-Neurobiology, Berlin, Germany.
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Contreras L, Drago I, Zampese E, Pozzan T. Mitochondria: the calcium connection. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:607-18. [PMID: 20470749 DOI: 10.1016/j.bbabio.2010.05.005] [Citation(s) in RCA: 252] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 05/04/2010] [Accepted: 05/04/2010] [Indexed: 12/21/2022]
Abstract
Calcium handling by mitochondria is a key feature in cell life. It is involved in energy production for cell activity, in buffering and shaping cytosolic calcium rises and also in determining cell fate by triggering or preventing apoptosis. Both mitochondria and the mechanisms involved in the control of calcium homeostasis have been extensively studied, but they still provide researchers with long-standing or even new challenges. Technical improvements in the tools employed for the investigation of calcium dynamics have been-and are still-opening new perspectives in this field, and more prominently for mitochondria. In this review we present a state-of-the-art toolkit for calcium measurements, with major emphasis on the advantages of genetically encoded indicators. These indicators can be efficiently and selectively targeted to specific cellular sub-compartments, allowing previously unavailable high-definition calcium dynamic studies. We also summarize the main features of cellular and, in more detail, mitochondrial calcium handling, especially focusing on the latest breakthroughs in the field, such as the recent direct characterization of the calcium microdomains that occur on the mitochondrial surface upon cellular stimulation. Additionally, we provide a major example of the key role played by calcium in patho-physiology by briefly describing the extensively reported-albeit highly controversial-alterations of calcium homeostasis in Alzheimer's disease, casting lights on the possible alterations in mitochondrial calcium handling in this pathology.
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Affiliation(s)
- Laura Contreras
- Department of Biomedical Sciences, University of Padua, Italy.
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Naumann EA, Kampff AR, Prober DA, Schier AF, Engert F. Monitoring neural activity with bioluminescence during natural behavior. Nat Neurosci 2010; 13:513-20. [PMID: 20305645 PMCID: PMC2846983 DOI: 10.1038/nn.2518] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 02/22/2010] [Indexed: 02/07/2023]
Abstract
Existing techniques for monitoring neural activity in awake, freely behaving vertebrates are invasive and difficult to target to genetically identified neurons. We used bioluminescence to non-invasively monitor the activity of genetically specified neurons in freely behaving zebrafish. Transgenic fish with the Ca(2+)-sensitive photoprotein green fluorescent protein (GFP)-Aequorin in most neurons generated large and fast bioluminescent signals that were related to neural activity, neuroluminescence, which could be recorded continuously for many days. To test the limits of this technique, we specifically targeted GFP-Aequorin to the hypocretin-positive neurons of the hypothalamus. We found that neuroluminescence generated by this group of approximately 20 neurons was associated with periods of increased locomotor activity and identified two classes of neural activity corresponding to distinct swim latencies. Our neuroluminescence assay can report, with high temporal resolution and sensitivity, the activity of small subsets of neurons during unrestrained behavior.
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Affiliation(s)
- Eva A Naumann
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
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