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Murphy KZ, Haile E, Tigue AM, Pierce AF, Donaldson ZR. PhAT: A Flexible Open-Source GUI-Driven Toolkit for Photometry Analysis. Curr Protoc 2023; 3:e763. [PMID: 37184156 PMCID: PMC10246504 DOI: 10.1002/cpz1.763] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Photometry approaches detect sensor-mediated changes in fluorescence as a proxy for rapid molecular changes within the brain. As a flexible technique with a relatively low cost to implement, photometry is rapidly being incorporated into neuroscience laboratories. Yet, although multiple data acquisition systems for photometry now exist, robust analytical pipelines for the resulting data remain limited. Here we present the Photometry Analysis Toolkit (PhAT)-a free open-source analysis pipeline that provides options for signal normalization, incorporation of multiple data streams to align photometry data with behavior and other events, calculation of event-related changes in fluorescence, and comparison of similarity across fluorescent traces. A graphical user interface (GUI) enables use of this software without prior coding knowledge. In addition to providing foundational analytical tools, PhAT is designed to readily incorporate community-driven development of new modules for more bespoke analyses, and enables data to be easily exported to enable subsequent statistical testing and/or code-based analyses. In addition, we provide recommendations regarding technical aspects of photometry experiments, including sensor selection and validation, reference signal considerations, and best practices for experimental design and data collection. We hope that the distribution of this software and protocols will lower the barrier to entry for new photometry users and improve the quality of collected data, increasing transparency and reproducibility in photometry analyses. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Software and environment installation Alternate Protocol 1: Software and environment update Basic Protocol 2: GUI-driven fiber photometry analysis Support Protocol 1: Examining signal quality Support Protocol 2: Interacting with graphs Basic Protocol 3: Adding modules to PhAT Alternate Protocol 2: Creating functions for use in Jupyter Notebook.
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Affiliation(s)
- Kathleen Z. Murphy
- Department of Psychology & Neuroscience, 345 UCB, University of Colorado Boulder, Boulder, CO 80304
| | - Eyobel Haile
- Department of Psychology & Neuroscience, 345 UCB, University of Colorado Boulder, Boulder, CO 80304
| | - Anna Mc Tigue
- Department of Computer Science, 430 UCB, University of Colorado Boulder, Boulder, CO 80304
| | - Anne F. Pierce
- Department of Psychology & Neuroscience, 345 UCB, University of Colorado Boulder, Boulder, CO 80304
| | - Zoe R. Donaldson
- Department of Psychology & Neuroscience, 345 UCB, University of Colorado Boulder, Boulder, CO 80304
- Department of Computer Science, 430 UCB, University of Colorado Boulder, Boulder, CO 80304
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2
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Serrat R, Oliveira-Pinto A, Marsicano G, Pouvreau S. Imaging mitochondrial calcium dynamics in the central nervous system. J Neurosci Methods 2022; 373:109560. [PMID: 35320763 DOI: 10.1016/j.jneumeth.2022.109560] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 03/04/2022] [Accepted: 03/06/2022] [Indexed: 12/28/2022]
Abstract
Mitochondrial calcium handling is a particularly active research area in the neuroscience field, as it plays key roles in the regulation of several functions of the central nervous system, such as synaptic transmission and plasticity, astrocyte calcium signaling, neuronal activity… In the last few decades, a panel of techniques have been developed to measure mitochondrial calcium dynamics, relying mostly on photonic microscopy, and including synthetic sensors, hybrid sensors and genetically encoded calcium sensors. The goal of this review is to endow the reader with a deep knowledge of the historical and latest tools to monitor mitochondrial calcium events in the brain, as well as a comprehensive overview of the current state of the art in brain mitochondrial calcium signaling. We will discuss the main calcium probes used in the field, their mitochondrial targeting strategies, their key properties and major drawbacks. In addition, we will detail the main roles of mitochondrial calcium handling in neuronal tissues through an extended report of the recent studies using mitochondrial targeted calcium sensors in neuronal and astroglial cells, in vitro and in vivo.
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Affiliation(s)
- Roman Serrat
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, France; University of Bordeaux, Bordeaux 33077, France
| | - Alexandre Oliveira-Pinto
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, France; University of Bordeaux, Bordeaux 33077, France
| | - Giovanni Marsicano
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, France; University of Bordeaux, Bordeaux 33077, France
| | - Sandrine Pouvreau
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, France; University of Bordeaux, Bordeaux 33077, France.
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Redolfi N, García-Casas P, Fornetto C, Sonda S, Pizzo P, Pendin D. Lighting Up Ca 2+ Dynamics in Animal Models. Cells 2021; 10:2133. [PMID: 34440902 PMCID: PMC8392631 DOI: 10.3390/cells10082133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/08/2021] [Accepted: 08/16/2021] [Indexed: 12/11/2022] Open
Abstract
Calcium (Ca2+) signaling coordinates are crucial processes in brain physiology. Particularly, fundamental aspects of neuronal function such as synaptic transmission and neuronal plasticity are regulated by Ca2+, and neuronal survival itself relies on Ca2+-dependent cascades. Indeed, impaired Ca2+ homeostasis has been reported in aging as well as in the onset and progression of neurodegeneration. Understanding the physiology of brain function and the key processes leading to its derangement is a core challenge for neuroscience. In this context, Ca2+ imaging represents a powerful tool, effectively fostered by the continuous amelioration of Ca2+ sensors in parallel with the improvement of imaging instrumentation. In this review, we explore the potentiality of the most used animal models employed for Ca2+ imaging, highlighting their application in brain research to explore the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Nelly Redolfi
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Paloma García-Casas
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Chiara Fornetto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Sonia Sonda
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
| | - Diana Pendin
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
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4
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Redolfi N, Greotti E, Zanetti G, Hochepied T, Fasolato C, Pendin D, Pozzan T. A New Transgenic Mouse Line for Imaging Mitochondrial Calcium Signals. FUNCTION 2021; 2:zqab012. [PMID: 35330679 PMCID: PMC8788866 DOI: 10.1093/function/zqab012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 02/24/2021] [Indexed: 01/06/2023] Open
Abstract
Mitochondria play a key role in cellular calcium (Ca2+) homeostasis. Dysfunction in the organelle Ca2+ handling appears to be involved in several pathological conditions, ranging from neurodegenerative diseases, cardiac failure and malignant transformation. In the past years, several targeted green fluorescent protein (GFP)-based genetically encoded Ca2+ indicators (GECIs) have been developed to study Ca2+ dynamics inside mitochondria of living cells. Surprisingly, while there is a number of transgenic mice expressing different types of cytosolic GECIs, few examples are available expressing mitochondria-localized GECIs, and none of them exhibits adequate spatial resolution. Here we report the generation and characterization of a transgenic mouse line (hereafter called mt-Cam) for the controlled expression of a mitochondria-targeted, Förster resonance energy transfer (FRET)-based Cameleon, 4mtD3cpv. To achieve this goal, we engineered the mouse ROSA26 genomic locus by inserting the optimized sequence of 4mtD3cpv, preceded by a loxP-STOP-loxP sequence. The probe can be readily expressed in a tissue-specific manner upon Cre recombinase-mediated excision, obtainable with a single cross. Upon ubiquitous Cre expression, the Cameleon is specifically localized in the mitochondrial matrix of cells in all the organs and tissues analyzed, from embryos to aged animals. Ca2+ imaging experiments performed in vitro and ex vivo in brain slices confirmed the functionality of the probe in isolated cells and live tissues. This new transgenic mouse line allows the study of mitochondrial Ca2+ dynamics in different tissues with no invasive intervention (such as viral infection or electroporation), potentially allowing simple calibration of the fluorescent signals in terms of mitochondrial Ca2+ concentration ([Ca2+]).
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Affiliation(s)
- Nelly Redolfi
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy
| | - Elisa Greotti
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy
- Neuroscience Institute, Italian National Research Council (CNR), Via U. Bassi 58/B, 35131 Padua, Italy
| | - Giulia Zanetti
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy
| | - Tino Hochepied
- VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Cristina Fasolato
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy
| | - Diana Pendin
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy
- Neuroscience Institute, Italian National Research Council (CNR), Via U. Bassi 58/B, 35131 Padua, Italy
| | - Tullio Pozzan
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy
- Neuroscience Institute, Italian National Research Council (CNR), Via U. Bassi 58/B, 35131 Padua, Italy
- Veneto Institute of Molecular Medicine (VIMM), Via G. Orus 2, 35129 Padua, Italy
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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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Vicente M, Salgado-Almario J, Soriano J, Burgos M, Domingo B, Llopis J. Visualization of Mitochondrial Ca 2+ Signals in Skeletal Muscle of Zebrafish Embryos with Bioluminescent Indicators. Int J Mol Sci 2019; 20:ijms20215409. [PMID: 31671636 PMCID: PMC6862566 DOI: 10.3390/ijms20215409] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/25/2019] [Accepted: 10/28/2019] [Indexed: 01/16/2023] Open
Abstract
Mitochondria are believed to play an important role in shaping the intracellular Ca2+ transients during skeletal muscle contraction. There is discussion about whether mitochondrial matrix Ca2+ dynamics always mirror the cytoplasmic changes and whether this happens in vivo in whole organisms. In this study, we characterized cytosolic and mitochondrial Ca2+ signals during spontaneous skeletal muscle contractions in zebrafish embryos expressing bioluminescent GFP-aequorin (GA, cytoplasm) and mitoGFP-aequorin (mitoGA, trapped in the mitochondrial matrix). The Ca2+ transients measured with GA and mitoGA reflected contractions of the trunk observed by transmitted light. The mitochondrial uncoupler FCCP and the inhibitor of the mitochondrial calcium uniporter (MCU), DS16570511, abolished mitochondrial Ca2+ transients whereas they increased the frequency of cytosolic Ca2+ transients and muscle contractions, confirming the subcellular localization of mitoGA. Mitochondrial Ca2+ dynamics were also determined with mitoGA and were found to follow closely cytoplasmic changes, with a slower decay. Cytoplasmic Ca2+ kinetics and propagation along the trunk and tail were characterized with GA and with the genetically encoded fluorescent Ca2+ indicator, Twitch-4. Although fluorescence provided a better spatio-temporal resolution, GA was able to resolve the same kinetic parameters while allowing continuous measurements for hours.
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Affiliation(s)
- Manuel Vicente
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain.
| | - Jussep Salgado-Almario
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain.
| | - Joaquim Soriano
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain.
| | - Miguel Burgos
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain.
| | - Beatriz Domingo
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain.
| | - Juan Llopis
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain.
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7
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Webb SE, Miller AL. The Use of Complementary Luminescent and Fluorescent Techniques for Imaging Ca 2+ Signaling Events During the Early Development of Zebrafish (Danio rerio). Methods Mol Biol 2019; 1929:73-93. [PMID: 30710268 DOI: 10.1007/978-1-4939-9030-6_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
We have visualized many of the Ca2+ signaling events that occur during the early stages of zebrafish development using complementary luminescent and fluorescent imaging techniques. We initially microinject embryos with the luminescent Ca2+ reporter, f-holo-aequorin, and using a custom-designed luminescent imaging system, we can obtain pan-embryonic visual information continually for up to the first ~24 h postfertilization (hpf). Once we know approximately when and where to look for these Ca2+ signaling events within a complex developing embryo, we then repeat the experiment using a fluorescent Ca2+ reporter such as calcium green-1 dextran and use confocal laser scanning microscopy to provide time-lapse series of higher-resolution images. These protocols allow us to identify the specific cell types and even the particular subcellular domain (e.g., nucleus or cytoplasm) generating the Ca2+ signal. Here, we outline the techniques we use to precisely microinject f-holo-aequorin or calcium green-1 dextran into embryos without affecting their viability or development. We also describe how to inject specific regions of early embryos in order to load localized embryonic domains with a particular Ca2+ reporter. These same techniques can also be used to introduce other membrane-impermeable reagents into embryos, including Ca2+ channel antagonists, Ca2+ chelators, fluorescent dyes, RNA, and DNA.
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Affiliation(s)
- Sarah E Webb
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, People's Republic of China.
| | - Andrew L Miller
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, People's Republic of China
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8
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Bhuckory S, Kays JC, Dennis AM. In Vivo Biosensing Using Resonance Energy Transfer. BIOSENSORS 2019; 9:E76. [PMID: 31163706 PMCID: PMC6628364 DOI: 10.3390/bios9020076] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/20/2019] [Accepted: 05/27/2019] [Indexed: 01/05/2023]
Abstract
Solution-phase and intracellular biosensing has substantially enhanced our understanding of molecular processes foundational to biology and pathology. Optical methods are favored because of the low cost of probes and instrumentation. While chromatographic methods are helpful, fluorescent biosensing further increases sensitivity and can be more effective in complex media. Resonance energy transfer (RET)-based sensors have been developed to use fluorescence, bioluminescence, or chemiluminescence (FRET, BRET, or CRET, respectively) as an energy donor, yielding changes in emission spectra, lifetime, or intensity in response to a molecular or environmental change. These methods hold great promise for expanding our understanding of molecular processes not just in solution and in vitro studies, but also in vivo, generating information about complex activities in a natural, organismal setting. In this review, we focus on dyes, fluorescent proteins, and nanoparticles used as energy transfer-based optical transducers in vivo in mice; there are examples of optical sensing using FRET, BRET, and in this mammalian model system. After a description of the energy transfer mechanisms and their contribution to in vivo imaging, we give a short perspective of RET-based in vivo sensors and the importance of imaging in the infrared for reduced tissue autofluorescence and improved sensitivity.
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Affiliation(s)
- Shashi Bhuckory
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
| | - Joshua C Kays
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
| | - Allison M Dennis
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
- Division of Materials Science and Engineering, Boston University, Boston, MA 02215, USA.
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9
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Yeh HW, Xiong Y, Wu T, Chen M, Ji A, Li X, Ai HW. ATP-Independent Bioluminescent Reporter Variants To Improve in Vivo Imaging. ACS Chem Biol 2019; 14:959-965. [PMID: 30969754 DOI: 10.1021/acschembio.9b00150] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Coelenterazine (CTZ)-utilizing marine luciferases and their derivatives have attracted significant attention because of their ATP-independency, fast enzymatic turnover, and high bioluminescence brightness. However, marine luciferases typically emit blue photons and their substrates, including CTZ and the recently developed diphenylterazine (DTZ), have poor water solubility, hindering their in vivo applications. Herein, we report a family of pyridyl CTZ and DTZ analogs that exhibit spectrally shifted emission and improved water solubility. Through directed evolution, we engineered a LumiLuc luciferase with broad substrate specificity. In the presence of corresponding pyridyl substrates (i.e., pyCTZ, 6pyDTZ, or 8pyDTZ), LumiLuc generates highly bright blue, teal, or yellow bioluminescence. We compared our LumiLuc-8pyDTZ pair with several benchmark reporters in a tumor xenograft mouse model. Our new pair, which does not need organic cosolvents for in vivo administration, surpasses other reporters by detecting early tumors. We further fused LumiLuc to a red fluorescent protein, resulting in a LumiScarlet reporter with further red-shifted emission and enhanced tissue penetration. LumiScarlet-8pyDTZ was comparable to Akaluc-AkaLumine, the brightest ATP-dependent luciferase-luciferin pair, for detecting cells in deep tissues of mice. In summary, we have engineered a new family of ATP-independent bioluminescent reporters, which will have broad applications because of their ATP-independency, excellent biocompatibility, and superior in vivo sensitivity.
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Affiliation(s)
- Hsien-Wei Yeh
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, Department of Chemistry, and the UVA Cancer Center, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia 22908, United States
| | - Ying Xiong
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, Department of Chemistry, and the UVA Cancer Center, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia 22908, United States
| | - Tianchen Wu
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, Department of Chemistry, and the UVA Cancer Center, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia 22908, United States
| | - Minghai Chen
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, Department of Chemistry, and the UVA Cancer Center, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia 22908, United States
| | - Ao Ji
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, Department of Chemistry, and the UVA Cancer Center, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia 22908, United States
| | - Xinyu Li
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, Department of Chemistry, and the UVA Cancer Center, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia 22908, United States
| | - Hui-wang Ai
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, Department of Chemistry, and the UVA Cancer Center, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia 22908, United States
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10
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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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11
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Ex Vivo Measurements of Ca 2+ Transients in Intracellular Compartments of Skeletal Muscle Fibers by Means of Genetically Encoded Probes. Methods Mol Biol 2019; 1925:103-109. [PMID: 30674020 DOI: 10.1007/978-1-4939-9018-4_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We report a method for ex vivo measurements of Ca2+ transients in skeletal muscle fibers, both in the sarcoplasma and into the mitochondria. These measurements are based on the use of genetically encoded probes. Addition of targeting DNA sequences, in frame with the probe encoding sequence, ensures protein expression in specific compartments. The use of probes with different excitation spectra allows the simultaneous determination of cytosolic and mitochondrial Ca2+ transients in the same fiber. Probe encoding plasmids are expressed in flexor digitorum brevis (FDB) muscles by means of the in vivo electroporation technique. Measurements are then performed ex vivo in isolated single myofibers.
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12
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Boss C, Bouche N, De Marchi U. Encapsulated Optically Responsive Cell Systems: Toward Smart Implants in Biomedicine. Adv Healthc Mater 2018; 7:e1701148. [PMID: 29283209 DOI: 10.1002/adhm.201701148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/06/2017] [Indexed: 01/09/2023]
Abstract
Managing increasingly prevalent chronic diseases will require close continuous monitoring of patients. Cell-based biosensors may be used for implantable diagnostic systems to monitor health status. Cells are indeed natural sensors in the body. Functional cellular systems can be maintained in the body for long-term implantation using cell encapsulation technology. By taking advantage of recent progress in miniaturized optoelectronic systems, the genetic engineering of optically responsive cells may be combined with cell encapsulation to generate smart implantable cell-based sensing systems. In biomedical research, cell-based biosensors may be used to study cell signaling, therapeutic effects, and dosing of bioactive molecules in preclinical models. Today, a wide variety of genetically encoded fluorescent sensors have been developed for real-time imaging of living cells. Here, recent developments in genetically encoded sensors, cell encapsulation, and ultrasmall optical systems are highlighted. The integration of these components in a new generation of biosensors is creating innovative smart in vivo cell-based systems, bringing novel perspectives for biomedical research and ultimately allowing unique health monitoring applications.
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Affiliation(s)
- Christophe Boss
- Device EngineeringNestlé Institute of Health Sciences EPFL Innovation Park Lausanne CH‐1015 Switzerland
| | - Nicolas Bouche
- Device EngineeringNestlé Institute of Health Sciences EPFL Innovation Park Lausanne CH‐1015 Switzerland
| | - Umberto De Marchi
- Mitochondrial FunctionNestlé Institute of Health Sciences EPFL Innovation Park Lausanne CH‐1015 Switzerland
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13
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Sharifian S, Homaei A, Hemmati R, B Luwor R, Khajeh K. The emerging use of bioluminescence in medical research. Biomed Pharmacother 2018; 101:74-86. [PMID: 29477474 DOI: 10.1016/j.biopha.2018.02.065] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 02/13/2018] [Accepted: 02/15/2018] [Indexed: 01/01/2023] Open
Abstract
Bioluminescence is the light produced by a living organism and is commonly emitted by sea life with Ca2+-regulated photoproteins being the most responsible for bioluminescence emission. Marine coelenterates provide important functions involved in essential purposes such as defense, feeding, and breeding. In this review, the main characteristics of marine photoproteins including aequorin, clytin, obelin, berovin, pholasin and symplectin from different marine organisms will be discussed. We will focused on the recent use of recombinant photoproteins in different biomedical research fields including the measurement of Ca2+ in different intracellular compartments of animal cells, as labels in the design and development of binding assays. This review will also outline how bioluminescent photoproteins have been used in a plethora of analytical methods including ultra-sensitive assays and in vivo imaging of cellular processes. Due to their unique properties including elective intracellular distribution, wide dynamic range, high signal-to-noise ratio and low Ca2+-buffering effect, recombinant photoproteins represent a promising future analytical tool in several in vitro and in vivo experiments.
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Affiliation(s)
- Sana Sharifian
- Department of Marine Biology, Faculty of Sciences, University of Hormozgan, Bandar Abbas, Iran
| | - Ahmad Homaei
- Department of Biochemistry, Faculty of Sciences, University of Hormozgan, Bandar Abbas, Iran.
| | - Roohullah Hemmati
- Department of Biology, Faculty of Basic Sciences, Shahrekord University, Shahrekord, Iran
| | - Rodney B Luwor
- Department of Surgery, Level 5, Clinical Sciences Building, The University of Melbourne, The Royal Melbourne Hospital, Grattan Street, Parkville, VIC 3050, Australia
| | - Khosro Khajeh
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
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14
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3D nerve cell cultures and complex physiological relevance. Drug Discov Today 2017; 23:22-25. [PMID: 29074438 DOI: 10.1016/j.drudis.2017.10.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 10/01/2017] [Accepted: 10/16/2017] [Indexed: 11/20/2022]
Abstract
The field of tissue engineering has not yet provided knowledge on which a consensus for the complex physiological relevance (CPR) of neuronal cultures could be established. The CPR of 3D neuronal cultures can have a profound impact on the drug discovery process through the validation of in vitro models for the study of neuropsychiatric and degenerative diseases, as well as screening for neurotoxicity during drug development. Herein, we assemble evidence in support of the potential of [Ca2+]i oscillation frequency as a CPR outcome that can demonstrate the in vivo-like behavior of 3D cultures and differentiate them from 2D monolayers. We demonstrate that [Ca2+]i oscillation frequencies in 2D cultures are significantly higher than those found in 3D cultures, and provide a possible molecular explanation.
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15
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Whitehead LW, McArthur K, Geoghegan ND, Rogers KL. The reinvention of twentieth century microscopy for three‐dimensional imaging. Immunol Cell Biol 2017; 95:520-524. [DOI: 10.1038/icb.2017.36] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 04/21/2017] [Accepted: 04/23/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Lachlan W Whitehead
- Walter and Eliza Hall Institute of Medical Research Parkville Victoria Australia
- Department of Medical Biology, University of Melbourne Parkville Victoria Australia
| | - Kate McArthur
- Walter and Eliza Hall Institute of Medical Research Parkville Victoria Australia
- Department of Medical Biology, University of Melbourne Parkville Victoria Australia
| | - Niall D Geoghegan
- Walter and Eliza Hall Institute of Medical Research Parkville Victoria Australia
- Department of Medical Biology, University of Melbourne Parkville Victoria Australia
| | - Kelly L Rogers
- Walter and Eliza Hall Institute of Medical Research Parkville Victoria Australia
- Department of Medical Biology, University of Melbourne Parkville Victoria Australia
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16
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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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17
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Alonso MT, Rodríguez-Prados M, Navas-Navarro P, Rojo-Ruiz J, García-Sancho J. Using aequorin probes to measure Ca 2+ in intracellular organelles. Cell Calcium 2017; 64:3-11. [PMID: 28214023 DOI: 10.1016/j.ceca.2017.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 01/11/2017] [Indexed: 11/28/2022]
Abstract
Aequorins are excellent tools for measuring intra-organellar Ca2+ and assessing its role in physiological and pathological functions. Here we review targeting strategies to express aequorins in various organelles. We address critical topics such as probe affinity tuning as well as normalization and calibration of the signal. We also focus on bioluminescent Ca2+ imaging in nucleus or mitochondria of living cells. Finally, recent advances with a new chimeric GFP-aequorin protein (GAP), which can be used either as luminescent or fluorescent Ca2+ probe, are presented. GAP is robustly expressed in transgenic flies and mice, where it has proven to be a suitable Ca2+ indicator for monitoring physiological Ca2+ signaling ex vivo and in vivo.
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Affiliation(s)
- María Teresa Alonso
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain.
| | - Macarena Rodríguez-Prados
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain
| | - Paloma Navas-Navarro
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain
| | - Jonathan Rojo-Ruiz
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain
| | - Javier García-Sancho
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain.
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18
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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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19
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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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20
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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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21
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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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22
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Cheng Z, Lin J. Synthesis and Application of Nanohybrids Based on Upconverting Nanoparticles and Polymers. Macromol Rapid Commun 2015; 36:790-827. [DOI: 10.1002/marc.201400588] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 01/29/2015] [Indexed: 01/13/2023]
Affiliation(s)
- Ziyong Cheng
- State Key Laboratory of Rare Earth Resource Utilization; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun 130022 P.R. China
| | - Jun Lin
- State Key Laboratory of Rare Earth Resource Utilization; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun 130022 P.R. China
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23
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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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24
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Frentzen A, Geissinger U, Tsoneva D, Stritzker J. Use of GLV-1h68 for Vaccinia Virotherapy and Monitoring. Methods Mol Biol 2015; 1317:225-237. [PMID: 26072410 DOI: 10.1007/978-1-4939-2727-2_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Herein we describe the use of the vaccinia virus strain GLV-1h68 as a theragnostic agent in cancer models. To date, GLV-1h68 has been used successfully in more than 50 xenograft tumor models. The recombinant vaccinia virus strain has been equipped with heterologous expression cassettes for a luciferase-fluorescent protein fusion gene, bacterial beta-galactosidase, as well as a bacterial glucuronidase. The methods to investigate and monitor GLV-1h68 mediated virotherapy, including optical imaging and biomarker analysis, will be presented in detail.
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Affiliation(s)
- Alexa Frentzen
- Genelux Corporation, 3030 Bunker Hill St, San Diego, CA, 92109, USA
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25
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Pendin D, Greotti E, Filadi R, Pozzan T. Spying on organelle Ca²⁺ in living cells: the mitochondrial point of view. J Endocrinol Invest 2015; 38:39-45. [PMID: 25245340 DOI: 10.1007/s40618-014-0178-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/15/2014] [Indexed: 01/04/2023]
Abstract
Over the past years, the use of genetically encoded Ca(2+) indicators (GECIs), derived from aequorin and green fluorescent protein, has profoundly transformed the study of Ca(2+) homeostasis in living cells leading to novel insights into functional aspects of Ca(2+) signalling. Particularly relevant for a deeper understanding of these key aspects of cell pathophysiology has been the possibility of imaging changes in Ca(2+) concentration not only in the cytoplasm, but also inside organelles. In this review, we will provide an overview of the ongoing developments in the use of GECIs, with particular focus on mitochondrially targeted probes. Indeed, due to recent advances in organelle Ca(2+) imaging with GECIs, mitochondria are now at the centre of renewed interest: they play key roles both in the physiology of the cell and in multiple pathological conditions relevant to human health.
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Affiliation(s)
- D Pendin
- Department of Biomedical Sciences, University of Padua, viale G. Colombo 3, 35131, Padua, Italy.
- Neuroscience Institute, National Research Council, viale G. Colombo 3, 35131, Padua, Italy.
| | - E Greotti
- Department of Biomedical Sciences, University of Padua, viale G. Colombo 3, 35131, Padua, Italy
- Neuroscience Institute, National Research Council, viale G. Colombo 3, 35131, Padua, Italy
| | - R Filadi
- Department of Biomedical Sciences, University of Padua, viale G. Colombo 3, 35131, Padua, Italy
| | - T Pozzan
- Department of Biomedical Sciences, University of Padua, viale G. Colombo 3, 35131, Padua, Italy
- Neuroscience Institute, National Research Council, viale G. Colombo 3, 35131, Padua, Italy
- Venetian Institute of Molecular Medicine, Via G. Orus 2, 35129, Padua, Italy
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26
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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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27
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Fluorescence-Based Methods for the Study of Protein Localization, Interaction, and Dynamics in Filamentous Fungi. Fungal Biol 2015. [DOI: 10.1007/978-3-319-22437-4_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Oheim M, van 't Hoff M, Feltz A, Zamaleeva A, Mallet JM, Collot M. New red-fluorescent calcium indicators for optogenetics, photoactivation and multi-color imaging. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1843:2284-306. [PMID: 24681159 DOI: 10.1016/j.bbamcr.2014.03.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 03/09/2014] [Indexed: 01/15/2023]
Abstract
Most chemical and, with only a few exceptions, all genetically encoded fluorimetric calcium (Ca(2+)) indicators (GECIs) emit green fluorescence. Many of these probes are compatible with red-emitting cell- or organelle markers. But the bulk of available fluorescent-protein constructs and transgenic animals incorporate green or yellow fluorescent protein (GFP and YFP respectively). This is, in part, not only heritage from the tendency to aggregate of early-generation red-emitting FPs, and due to their complicated photochemistry, but also resulting from the compatibility of green-fluorescent probes with standard instrumentation readily available in most laboratories and core imaging facilities. Photochemical constraints like limited water solubility and low quantum yield have contributed to the relative paucity of red-emitting Ca(2+) probes compared to their green counterparts, too. The increasing use of GFP and GFP-based functional reporters, together with recent developments in optogenetics, photostimulation and super-resolution microscopies, has intensified the quest for red-emitting Ca(2+) probes. In response to this demand more red-emitting chemical and FP-based Ca(2+)-sensitive indicators have been developed since 2009 than in the thirty years before. In this topical review, we survey the physicochemical properties of these red-emitting Ca(2+) probes and discuss their utility for biological Ca(2+) imaging. Using the spectral separability index Xijk (Oheim M., 2010. Methods in Molecular Biology 591: 3-16) we evaluate their performance for multi-color excitation/emission experiments, involving the identification of morphological landmarks with GFP/YFP and detecting Ca(2+)-dependent fluorescence in the red spectral band. We also establish a catalog of criteria for evaluating Ca(2+) indicators that ideally should be made available for each probe. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Martin Oheim
- CNRS, UMR 8154, Paris F-75006, France; INSERM, U603, Paris F-75006, France; University Paris Descartes, PRES Sorbonne Paris Cité, Laboratory of Neurophysiology and New Microscopies, 45 rue des Saints Pères, Paris F-75006, France.
| | - Marcel van 't Hoff
- CNRS, UMR 8154, Paris F-75006, France; INSERM, U603, Paris F-75006, France; University Paris Descartes, PRES Sorbonne Paris Cité, Laboratory of Neurophysiology and New Microscopies, 45 rue des Saints Pères, Paris F-75006, France; University of Florence, LENS - European Laboratory for Non-linear Spectroscopy, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
| | - Anne Feltz
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Paris F-75005, France; INSERM U1024, Paris F-75005, France; CNRS UMR 8197, Paris F-75005, France
| | - Alsu Zamaleeva
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Paris F-75005, France; INSERM U1024, Paris F-75005, France; CNRS UMR 8197, Paris F-75005, France
| | - Jean-Maurice Mallet
- UPMC Université́ Paris 06, Ecole Normale Supérieure (ENS), 24 rue Lhomond, Paris F-75005, France; CNRS UMR 7203, Paris F-75005, France
| | - Mayeul Collot
- UPMC Université́ Paris 06, Ecole Normale Supérieure (ENS), 24 rue Lhomond, Paris F-75005, France; CNRS UMR 7203, Paris F-75005, France
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Eisner V, Lenaers G, Hajnóczky G. Mitochondrial fusion is frequent in skeletal muscle and supports excitation-contraction coupling. ACTA ACUST UNITED AC 2014; 205:179-95. [PMID: 24751540 PMCID: PMC4003250 DOI: 10.1083/jcb.201312066] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Mitochondrial fusion is frequent in skeletal muscle, and its disruption jeopardizes excitation–contraction coupling and may contribute to the pathology of myopathies. Genetic targeting experiments indicate a fundamental role for mitochondrial fusion proteins in mammalian physiology. However, owing to the multiple functions of fusion proteins, their related phenotypes are not necessarily caused by altered mitochondrial fusion. Perhaps the biggest mystery is presented by skeletal muscle, where mostly globular-shaped mitochondria are densely packed into the narrow intermyofilamental space, limiting the interorganellar interactions. We show here that mitochondria form local networks and regularly undergo fusion events to share matrix content in skeletal muscle fibers. However, fusion events are less frequent and more stable in the fibers than in nondifferentiated myoblasts. Complementation among muscle mitochondria was suppressed by both in vivo genetic perturbations and chronic alcohol consumption that cause myopathy. An Mfn1-dependent pathway is revealed whereby fusion inhibition weakens the metabolic reserve of mitochondria to cause dysregulation of calcium oscillations during prolonged stimulation. Thus, fusion dynamically connects skeletal muscle mitochondria and its prolonged loss jeopardizes bioenergetics and excitation–contraction coupling, providing a potential pathomechanism contributing to myopathies.
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Affiliation(s)
- Verónica Eisner
- MitoCare Center, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107
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Calderón JC, Bolaños P, Caputo C. The excitation-contraction coupling mechanism in skeletal muscle. Biophys Rev 2014; 6:133-160. [PMID: 28509964 PMCID: PMC5425715 DOI: 10.1007/s12551-013-0135-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 12/06/2013] [Indexed: 12/27/2022] Open
Abstract
First coined by Alexander Sandow in 1952, the term excitation-contraction coupling (ECC) describes the rapid communication between electrical events occurring in the plasma membrane of skeletal muscle fibres and Ca2+ release from the SR, which leads to contraction. The sequence of events in twitch skeletal muscle involves: (1) initiation and propagation of an action potential along the plasma membrane, (2) spread of the potential throughout the transverse tubule system (T-tubule system), (3) dihydropyridine receptors (DHPR)-mediated detection of changes in membrane potential, (4) allosteric interaction between DHPR and sarcoplasmic reticulum (SR) ryanodine receptors (RyR), (5) release of Ca2+ from the SR and transient increase of Ca2+ concentration in the myoplasm, (6) activation of the myoplasmic Ca2+ buffering system and the contractile apparatus, followed by (7) Ca2+ disappearance from the myoplasm mediated mainly by its reuptake by the SR through the SR Ca2+ adenosine triphosphatase (SERCA), and under several conditions movement to the mitochondria and extrusion by the Na+/Ca2+ exchanger (NCX). In this text, we review the basics of ECC in skeletal muscle and the techniques used to study it. Moreover, we highlight some recent advances and point out gaps in knowledge on particular issues related to ECC such as (1) DHPR-RyR molecular interaction, (2) differences regarding fibre types, (3) its alteration during muscle fatigue, (4) the role of mitochondria and store-operated Ca2+ entry in the general ECC sequence, (5) contractile potentiators, and (6) Ca2+ sparks.
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Affiliation(s)
- Juan C Calderón
- Physiology and Biochemistry Research Group-Physis, Department of Physiology and Biochemistry, Faculty of Medicine, University of Antioquia UdeA, Calle 70 No 52-21, Medellín, Colombia.
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela.
- Departamento de Fisiología y Bioquímica, Grupo de Investigación en Fisiología y Bioquímica-Physis, Facultad de Medicina, Universidad de Antioquia, Calle 70 No 52-21, Medellín, Colombia.
| | - Pura Bolaños
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
| | - Carlo Caputo
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
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31
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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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GAP, an aequorin-based fluorescent indicator for imaging Ca2+ in organelles. Proc Natl Acad Sci U S A 2014; 111:2584-9. [PMID: 24501126 DOI: 10.1073/pnas.1316539111] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genetically encoded calcium indicators allow monitoring subcellular Ca(2+) signals inside organelles. Most genetically encoded calcium indicators are fusions of endogenous calcium-binding proteins whose functionality in vivo may be perturbed by competition with cellular partners. We describe here a novel family of fluorescent Ca(2+) sensors based on the fusion of two Aequorea victoria proteins, GFP and apo-aequorin (GAP). GAP exhibited a unique combination of features: dual-excitation ratiometric imaging, high dynamic range, good signal-to-noise ratio, insensitivity to pH and Mg(2+), tunable Ca(2+) affinity, uncomplicated calibration, and targetability to five distinct organelles. Moreover, transgenic mice for endoplasmic reticulum-targeted GAP exhibited a robust long-term expression that correlated well with its reproducible performance in various neural tissues. This biosensor fills a gap in the actual repertoire of Ca(2+) indicators for organelles and becomes a valuable tool for in vivo Ca(2+) imaging applications.
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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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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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35
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Eisner V, Csordás G, Hajnóczky G. Interactions between sarco-endoplasmic reticulum and mitochondria in cardiac and skeletal muscle - pivotal roles in Ca²⁺ and reactive oxygen species signaling. J Cell Sci 2013; 126:2965-78. [PMID: 23843617 DOI: 10.1242/jcs.093609] [Citation(s) in RCA: 156] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mitochondria are strategically and dynamically positioned in the cell to spatially coordinate ATP production with energy needs and to allow the local exchange of material with other organelles. Interactions of mitochondria with the sarco-endoplasmic reticulum (SR/ER) have been receiving much attention owing to emerging evidence on the role these sites have in cell signaling, dynamics and biosynthetic pathways. One of the most important physiological and pathophysiological paradigms for SR/ER-mitochondria interactions is in cardiac and skeletal muscle. The contractile activity of these tissues has to be matched by mitochondrial ATP generation that is achieved, at least in part, by propagation of Ca(2+) signals from SR to mitochondria. However, the muscle has a highly ordered structure, providing only limited opportunity for mitochondrial dynamics and interorganellar interactions. This Commentary focuses on the latest advances in the structure, function and disease relevance of the communication between SR/ER and mitochondria in muscle. In particular, we discuss the recent demonstration of SR/ER-mitochondria tethers that are formed by multiple proteins, and local Ca(2+) transfer between SR/ER and mitochondria.
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Affiliation(s)
- Verónica Eisner
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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36
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Glancy B, Willis WT, Chess DJ, Balaban RS. Effect of calcium on the oxidative phosphorylation cascade in skeletal muscle mitochondria. Biochemistry 2013; 52:2793-809. [PMID: 23547908 DOI: 10.1021/bi3015983] [Citation(s) in RCA: 215] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Calcium is believed to regulate mitochondrial oxidative phosphorylation, thereby contributing to the maintenance of cellular energy homeostasis. Skeletal muscle, with an energy conversion dynamic range of up to 100-fold, is an extreme case for evaluating the cellular balance of ATP production and consumption. This study examined the role of Ca(2+) in the entire oxidative phosphorylation reaction network in isolated skeletal muscle mitochondria and attempted to extrapolate these results back to the muscle, in vivo. Kinetic analysis was conducted to evaluate the dose-response effect of Ca(2+) on the maximal velocity of oxidative phosphorylation (V(maxO)) and the ADP affinity. Force-flow analysis evaluated the interplay between energetic driving forces and flux to determine the conductance, or effective activity, of individual steps within oxidative phosphorylation. Measured driving forces [extramitochondrial phosphorylation potential (ΔG(ATP)), membrane potential, and redox states of NADH and cytochromes b(H), b(L), c(1), c, and a,a(3)] were compared with flux (oxygen consumption) at 37 °C; 840 nM Ca(2+) generated an ~2-fold increase in V(maxO) with no change in ADP affinity (~43 μM). Force-flow analysis revealed that Ca(2+) activation of V(maxO) was distributed throughout the oxidative phosphorylation reaction sequence. Specifically, Ca(2+) increased the conductance of Complex IV (2.3-fold), Complexes I and III (2.2-fold), ATP production/transport (2.4-fold), and fuel transport/dehydrogenases (1.7-fold). These data support the notion that Ca(2+) activates the entire muscle oxidative phosphorylation cascade, while extrapolation of these data to the exercising muscle predicts a significant role of Ca(2+) in maintaining cellular energy homeostasis.
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Affiliation(s)
- Brian Glancy
- Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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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: 67] [Impact Index Per Article: 6.1] [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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Genetically encoded Ca(2+) indicators: properties and evaluation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1787-97. [PMID: 23352808 DOI: 10.1016/j.bbamcr.2013.01.011] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 01/02/2013] [Accepted: 01/10/2013] [Indexed: 02/04/2023]
Abstract
Genetically encoded calcium ion (Ca(2+)) indicators have become very useful and widely used tools for Ca(2+) imaging, not only in cellular models, but also in living organisms. However, the in vivo and in situ characterization of these indicators is tedious and time consuming, and it does not provide information regarding the suitability of an indicator for particular experimental environments. Thus, initial in vitro evaluation of these tools is typically performed to determine their properties. In this review, we examined the properties of dynamic range, affinity, selectivity, and kinetics for Ca(2+) indicators. Commonly used strategies for evaluating these properties are presented. This article is part of a Special Issue entitled: 12th European Symposium on Calcium.
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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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40
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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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41
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Kim HS, Czymmek KJ, Patel A, Modla S, Nohe A, Duncan R, Gilroy S, Kang S. Expression of the Cameleon calcium biosensor in fungi reveals distinct Ca(2+) signatures associated with polarized growth, development, and pathogenesis. Fungal Genet Biol 2012; 49:589-601. [PMID: 22683653 DOI: 10.1016/j.fgb.2012.05.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 05/22/2012] [Accepted: 05/24/2012] [Indexed: 11/19/2022]
Abstract
Calcium is a universal messenger that translates diverse environmental stimuli and developmental cues into specific cellular and developmental responses. While individual fungal species have evolved complex and often unique biochemical and structural mechanisms to exploit specific ecological niches and to adjust growth and development in response to external stimuli, one universal feature to all is that Ca(2+)-mediated signaling is involved. The lack of a robust method for imaging spatial and temporal dynamics of subcellular Ca(2+) (i.e., "Ca(2+) signature"), readily available in the plant and animal systems, has severely limited studies on how this signaling pathway controls fungal growth, development, and pathogenesis. Here, we report the first successful expression of a FRET (Förster Resonance Energy Transfer)-based Ca(2+) biosensor in fungi. Time-lapse imaging of Magnaporthe oryzae, Fusarium oxysporum, and Fusarium graminearum expressing this sensor showed that instead of a continuous gradient, the cytoplasmic Ca(2+) ([Ca(2+)](c)) change occurred in a pulsatile manner with no discernable gradient between pulses, and each species exhibited a distinct Ca(2+) signature. Furthermore, occurrence of pulsatile Ca(2+) signatures was age and development dependent, and major [Ca(2+)](c) transients were observed during hyphal branching, septum formation, differentiation into specialized plant infection structures, cell-cell contact and in planta growth. In combination with the sequenced genomes and ease of targeted gene manipulation of these and many other fungal species, the data, materials and methods developed here will help understand the mechanism underpinning Ca(2+)-mediated control of cellular and developmental changes, its role in polarized growth forms and the evolution of Ca(2+) signaling across eukaryotic kingdoms.
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Affiliation(s)
- Hye-Seon Kim
- Department of Plant Pathology, The Pennsylvania State University, University Park, PA 16802, United States
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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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Bakayan A, Vaquero CF, Picazo F, Llopis J. Red fluorescent protein-aequorin fusions as improved bioluminescent Ca2+ reporters in single cells and mice. PLoS One 2011; 6:e19520. [PMID: 21589654 PMCID: PMC3092744 DOI: 10.1371/journal.pone.0019520] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 04/08/2011] [Indexed: 11/18/2022] Open
Abstract
Bioluminescence recording of Ca(2+) signals with the photoprotein aequorin does not require radiative energy input and can be measured with a low background and good temporal resolution. Shifting aequorin emission to longer wavelengths occurs naturally in the jellyfish Aequorea victoria by bioluminescence resonance energy transfer (BRET) to the green fluorescent protein (GFP). This process has been reproduced in the molecular fusions GFP-aequorin and monomeric red fluorescent protein (mRFP)-aequorin, but the latter showed limited transfer efficiency. Fusions with strong red emission would facilitate the simultaneous imaging of Ca(2+) in various cell compartments. In addition, they would also serve to monitor Ca(2+) in living organisms since red light is able to cross animal tissues with less scattering. In this study, aequorin was fused to orange and various red fluorescent proteins to identify the best acceptor in red emission bands. Tandem-dimer Tomato-aequorin (tdTA) showed the highest BRET efficiency (largest energy transfer critical distance R(0)) and percentage of counts in the red band of all the fusions studied. In addition, red fluorophore maturation of tdTA within cells was faster than that of other fusions. Light output was sufficient to image ATP-induced Ca(2+) oscillations in single HeLa cells expressing tdTA. Ca(2+) rises caused by depolarization of mouse neuronal cells in primary culture were also recorded, and changes in fine neuronal projections were spatially resolved. Finally, it was also possible to visualize the Ca(2+) activity of HeLa cells injected subcutaneously into mice, and Ca(2+) signals after depositing recombinant tdTA in muscle or the peritoneal cavity. Here we report that tdTA is the brightest red bioluminescent Ca(2+) sensor reported to date and is, therefore, a promising probe to study Ca(2+) dynamics in whole organisms or tissues expressing the transgene.
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Affiliation(s)
- Adil Bakayan
- Facultad de Medicina and Centro Regional de Investigaciones Biomédicas (CRIB), University of Castilla-La Mancha, Albacete, Spain
| | - Cecilia F. Vaquero
- Facultad de Medicina and Centro Regional de Investigaciones Biomédicas (CRIB), University of Castilla-La Mancha, Albacete, Spain
| | - Fernando Picazo
- Facultad de Medicina and Centro Regional de Investigaciones Biomédicas (CRIB), University of Castilla-La Mancha, Albacete, Spain
| | - Juan Llopis
- Facultad de Medicina and Centro Regional de Investigaciones Biomédicas (CRIB), University of Castilla-La Mancha, Albacete, Spain
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Snoeks TJA, Khmelinskii A, Lelieveldt BPF, Kaijzel EL, Löwik CWGM. Optical advances in skeletal imaging applied to bone metastases. Bone 2011; 48:106-14. [PMID: 20688203 DOI: 10.1016/j.bone.2010.07.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Accepted: 07/28/2010] [Indexed: 12/21/2022]
Abstract
Optical Imaging has evolved into one of the standard molecular imaging modalities used in pre-clinical cancer research. Bone research however, strongly depends on other imaging modalities such as SPECT, PET, x-ray and μCT. Each imaging modality has its own specific strengths and weaknesses concerning spatial resolution, sensitivity and the possibility to quantify the signal. An increasing number of bone specific optical imaging models and probes have been developed over the past years. This review gives an overview of optical imaging modalities, models and probes that can be used to study skeletal complications of cancer in small laboratory animals.
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Affiliation(s)
- T J A Snoeks
- Department of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands.
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45
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Eglen R, Reisine T. Primary cells and stem cells in drug discovery: emerging tools for high-throughput screening. Assay Drug Dev Technol 2010; 9:108-24. [PMID: 21186936 DOI: 10.1089/adt.2010.0305] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many drug discovery screening programs employ immortalized cells, recombinantly engineered to express a defined molecular target. Several technologies are now emerging that render it feasible to employ more physiologically, and clinically relevant, cell phenotypes. Consequently, numerous approaches use primary cells, which retain many functions seen in vivo, as well as endogenously expressing the target of interest. Furthermore, stem cells, of either embryonic or adult origin, as well as those derived from differentiated cells, are now finding a place in drug discovery. Collectively, these cells are expanding the utility of authentic human cells, either as screening tools or as therapeutics, as well as providing cells derived directly from patients. Nonetheless, the growing use of phenotypically relevant cells (including primary cells or stem cells) is not without technical difficulties, particularly when their envisioned use lies in high-throughput screening (HTS) protocols. In particular, the limited availability of homogeneous primary or stem cell populations for HTS mandates that novel technologies be developed to accelerate their adoption. These technologies include detection of responses with very few cells as well as protocols to generate cell lines in abundant, homogeneous populations. In parallel, the growing use of changes in cell phenotype as the assay readout is driving greater use of high-throughput imaging techniques in screening. Taken together, the greater availability of novel primary and stem cell phenotypes as well as new detection technologies is heralding a new era of cellular screening. This convergence offers unique opportunities to identify drug candidates for disorders at which few therapeutics are presently available.
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Affiliation(s)
- Richard Eglen
- Bio-discovery, PerkinElmer, Waltham, Massachusetts 02451-1457, USA.
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Eisner V, Parra V, Lavandero S, Hidalgo C, Jaimovich E. Mitochondria fine-tune the slow Ca(2+) transients induced by electrical stimulation of skeletal myotubes. Cell Calcium 2010; 48:358-70. [PMID: 21106237 DOI: 10.1016/j.ceca.2010.11.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 10/25/2010] [Accepted: 11/01/2010] [Indexed: 01/22/2023]
Abstract
Mitochondria sense cytoplasmic Ca(2+) signals in many cell types. In mammalian skeletal myotubes, depolarizing stimuli induce two independent cytoplasmic Ca(2+) signals: a fast signal associated with contraction and a slow signal that propagates to the nucleus and regulates gene expression. How mitochondria sense and possibly affect these cytoplasmic Ca(2+) signals has not been reported. We investigated here (a) the emergence of mitochondrial Ca(2+) signals in response to electrical stimulation of myotubes, (b) the contribution of mitochondrial Ca(2+) transients to ATP generation and (c) the influence of mitochondria as modulators of cytoplasmic and nuclear Ca(2+) signals. Rhod2 and Fluo3 fluorescence determinations revealed composite Ca(2+) signals associated to the mitochondrial compartment in electrically stimulated (400 pulses, 45 Hz) skeletal myotubes. Similar Ca(2+) signals were detected when using a mitochondria-targeted pericam. The fast mitochondrial Ca(2+) rise induced by stimulation was inhibited by pre-incubation with ryanodine, whereas the phospholipase C inhibitor U73122 blocked the slow mitochondrial Ca(2+) signal, showing that mitochondria sense the two cytoplasmic Ca(2+) signal components. The fast but not the slow Ca(2+) transient enhanced mitochondrial ATP production. Inhibition of the mitochondrial Ca(2+) uniporter prevented the emergence of mitochondrial Ca(2+) transients and significantly increased the magnitude of slow cytoplasmic Ca(2+) signals after stimulation. Precluding mitochondrial Ca(2+) extrusion with the Na(+)/Ca(2+) exchanger inhibitor CGP37157 decreased mitochondrial potential, increased the magnitude of the slow cytoplasmic Ca(2+) signal and decreased the rate of Ca(2+) signal propagation from one nucleus to the next. Over expression of the mitochondrial fission protein Drp-1 decreased mitochondrial size and the slow Ca(2+) transient in mitochondria, but enhanced cytoplasmic and nuclear slow transients. The present results indicate that mitochondria play a central role in the regulation of Ca(2+) signals involved in gene expression in myotubes.
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Affiliation(s)
- Veronica Eisner
- Centro de Estudios Moleculares de la Celula, Universidad de Chile, Instituto de Ciencias Biomédicas, Facultad de Medicina, Santiago 8380492, Chile
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Model-based multi-view fusion of cinematic flow and optical imaging. MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION : MICCAI ... INTERNATIONAL CONFERENCE ON MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION 2010; 13:668-75. [PMID: 20879373 DOI: 10.1007/978-3-642-15745-5_82] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Bioluminescence imaging (BLI) offers the possibility to study and image biology at molecular scale in small animals with applications in oncology or gene expression studies. Here we present a novel model-based approach to 3D animal tracking from monocular video which allows the quantification of bioluminescence signal on freely moving animals. The 3D animal pose and the illumination are dynamically estimated through minimization of an objective function with constraints on the bioluminescence signal position. Derived from an inverse problem formulation, the objective function enables explicit use of temporal continuity and shading information, while handling important self-occlusions and time-varying illumination. In this model-based framework, we include a constraint on the 3D position of bioluminescence signal to enforce tracking of the biologically produced signal. The minimization is done efficiently using a quasi-Newton method, with a rigorous derivation of the objective function gradient. Promising experimental results demonstrate the potentials of our approach for 3D accurate measurement with freely moving animal.
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48
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In vivo simultaneous intra- and extracellular potassium recordings using a micro-optrode. J Neurosci Methods 2010; 194:206-17. [PMID: 20951737 DOI: 10.1016/j.jneumeth.2010.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 09/28/2010] [Accepted: 10/07/2010] [Indexed: 01/30/2023]
Abstract
This technique proposes a new approach to correlate intra- and extracellular variations of the ionic concentrations in vivo by means of tapered optical waveguides coupled to standard electrophysiological electrodes to monitor in vivo simultaneously the intracellular and extracellular K(+) concentration as well as the neighboring field potential. The optical fibers were tapered to a final diameter of approximately 10 μm and were used to guide the excitation light deep into the tissue and to collect the fluorescence emanating from the intracellular milieu. This fiber was coupled to a double barrel ion-sensitive electrode forming a micro-optrode with a final diameter around 15 μm. The method was successfully used to record the intracellular K(+) evolution with the fluorescent indicator PBFI during three states: normal sleep-like patterns, paroxysmal seizures, and coma. While we could not disclose any phasic fluctuations of the intracellular K(+) during normal sleep patterns, they were clearly present during seizures and coma. In the majority of cases (58%), paroxysmal discharges were associated with positive variations of the intracellular fluorescence of 62±5% corresponding to extracellular K(+) increases of 2.04±0.4 mM. In the remaining cases (42%) intracellular K(+) dropped by 44.4±12% for an extracellular K(+) increase of 2.62±0.47 mM. We suggest that this differential behavior might reflect different cellular populations (glia vs. neurons, respectively). Comatose states were accompanied by an extracellular drop of K(+) of 1.31±0.13 mM, which was reflected, in all cases, by an intracellular K(+) increase of 39±4%.
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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: 254] [Impact Index Per Article: 18.1] [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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Snoeks TJA, Löwik CWGM, Kaijzel EL. 'In vivo' optical approaches to angiogenesis imaging. Angiogenesis 2010; 13:135-47. [PMID: 20449766 PMCID: PMC2911541 DOI: 10.1007/s10456-010-9168-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 04/20/2010] [Indexed: 10/27/2022]
Abstract
In recent years, molecular imaging gained significant importance in biomedical research. Optical imaging developed into a modality which enables the visualization and quantification of all kinds of cellular processes and cancerous cell growth in small animals. Novel gene reporter mice and cell lines and the development of targeted and cleavable fluorescent "smart" probes form a powerful imaging toolbox. The development of systems collecting tomographic bioluminescence and fluorescence data enabled even more spatial accuracy and more quantitative measurements. Here we describe various bioluminescent and fluorescent gene reporter models and probes that can be used to specifically image and quantify neovascularization or the angiogenic process itself.
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Affiliation(s)
- T J A Snoeks
- Department of Endocrinology, Leiden University Medical Center, Building 1, C4-R86, Albinusdreef 2, 2333ZA, Leiden, The Netherlands
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