1
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Suckert C, Zosel C, Schaefer M. Simultaneous TIRF imaging of subplasmalemmal Ca 2+ dynamics and granule fusions in insulin-secreting INS-1 cells reveals coexistent synchronized and asynchronous release. Cell Calcium 2024; 120:102883. [PMID: 38643716 DOI: 10.1016/j.ceca.2024.102883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/21/2024] [Accepted: 03/29/2024] [Indexed: 04/23/2024]
Abstract
The basal and glucose-induced insulin secretion from pancreatic beta cells is a tightly regulated process that is triggered in a Ca2+-dependent fashion and further positively modulated by substances that raise intracellular levels of adenosine 3',5'-cyclic monophosphate (cAMP) or by certain antidiabetic drugs. In a previous study, we have temporally resolved the subplasmalemmal [Ca2+]i dynamics in beta cells that are characterized by trains of sharply delimited spikes, reaching peak values up to 5 µM. Applying total internal reflection fluorescence (TIRF) microscopy and synaptopHluorin to visualize fusion events of individual granules, we found that several fusion events can coincide within 50 to 150 ms. To test whether subplasmalemmal [Ca2+]i microdomains around single or clustered Ca2+ channels may cause a synchronized release of insulin-containing vesicles, we applied simultaneous dual-color TIRF microscopy and monitored Ca2+ fluctuations and exocytotic events in INS-1 cells at high frame rates. The results indicate that fusions can be triggered by subplasmalemmal Ca2+ spiking. This, however, does account for a minority of fusion events. About 90 %-95 % of fusion events either happen between Ca2+ spikes or incidentally overlap with subplasmalemmal Ca2+ spikes. We conclude that only a fraction of exocytotic events in glucose-induced and tolbutamide- or forskolin-enhanced insulin release from INS-1 cells is tightly coupled to Ca2+ microdomains around voltage-gated Ca2+ channels.
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Affiliation(s)
- Charlotte Suckert
- Leipzig University, Rudolf-Boehm-Institute of Pharmacology and Toxicology, Härtelstraße 16-18, Leipzig 04107, Germany
| | - Carolin Zosel
- Leipzig University, Rudolf-Boehm-Institute of Pharmacology and Toxicology, Härtelstraße 16-18, Leipzig 04107, Germany
| | - Michael Schaefer
- Leipzig University, Rudolf-Boehm-Institute of Pharmacology and Toxicology, Härtelstraße 16-18, Leipzig 04107, Germany.
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2
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Kirchhoff F, Tang W. Analysis of Functional NMDA Receptors in Astrocytes. Methods Mol Biol 2024; 2799:201-223. [PMID: 38727909 DOI: 10.1007/978-1-0716-3830-9_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Neuronal N-methyl-D-aspartate (NMDA) receptors are well known for their pivotal role in memory formation. Originally, they were thought to be exclusive to neurons. However, numerous studies revealed their functional expression also on various types of glial cells in the nervous system. Here, the methodology on how to study the physiology of NMDA receptors selectively on astrocytes will be described in detail. Astrocytes are the main class of neuroglia that control transmitter and ion homeostasis, which link cerebral blood flow and neuronal energy demands, but also affect synaptic transmission directly.
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Affiliation(s)
- Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Wannan Tang
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
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3
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Emerson JI, Ariel P, Shi W, Conlon FL. Sex Differences in Mouse Cardiac Electrophysiology Revealed by Simultaneous Imaging of Excitation-Contraction Coupling. J Cardiovasc Dev Dis 2023; 10:479. [PMID: 38132647 PMCID: PMC10743987 DOI: 10.3390/jcdd10120479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Males and females differ in the basic anatomy and physiology of the heart. Sex differences are evident in cardiac repolarization in humans; women have longer corrected QT and JT intervals. However, the molecular mechanisms that lead to these differences are incompletely understood. Here, we present that, like in humans, sex differences in QT and JT intervals exist in mouse models; female mice had longer corrected QT and JT intervals compared with age-matched males. To further understand the molecular underpinning of these sex differences, we developed a novel technology using fluorescent confocal microscopy that allows the simultaneous visualization of action potential, Ca2+ transients, and contractions in isolated cardiomyocytes at a high temporal resolution. From this approach, we uncovered that females at baseline have increased action potential duration, decreased Ca2+ release and reuptake rates, and decreased contraction and relaxation velocities compared with males. Additionally, males had a shorter overall time from action potential onset to peak contraction. In aggregate, our studies uncovered male and female differences in excitation-contraction coupling that account for differences observed in the EKG. Overall, a better understanding of sex differences in electrophysiology is essential for equitably treating cardiac disease.
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Affiliation(s)
- James I. Emerson
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - Pablo Ariel
- Microscopy Services Laboratory, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - Wei Shi
- Department of Biology and Genetics, McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - Frank L. Conlon
- Department of Biology and Genetics, McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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4
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Kumada R, Sakama A, Shindo Y, Kuronuma Y, Iwasawa N, Citterio D, Oka K, Hiruta Y. Development of Phosphinate Ligand-Based Low-Affinity Ca 2+ Fluorescent Probes and Application to Intracellular Ca 2+ Imaging. Anal Chem 2023; 95:16683-16691. [PMID: 37922450 DOI: 10.1021/acs.analchem.3c03266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2023]
Abstract
Divalent metal cations such as calcium ion (Ca2+) and magnesium ion (Mg2+) are indispensable to the regulation of various cellular activities. In this research, we developed the KLCA series utilizing o-aminophenol-N,N-diacetate-O-methylene-methylphosphinate (APDAP) as a target binding site, which was reported recently as a highly free Mg2+-selective ligand. KLCA-301 with orange fluorescence based on a rhodamine fluorophore and KLCA-501 with near-infrared (NIR) fluorescence based on a Si-rhodamine fluorophore were synthesized, intended for application to multicolor imaging. The evaluation of the fluorescence response to Ca2+ and Mg2+ of the KLCA series indicated the applicability as low-affinity Ca2+ probes. While KLCA-301 mainly localized in the cytosol in cultured rat hippocampal neurons, KLCA-501 localized to the cytosol and granular organelles in neurons. Comparison of the fluorescence response of KLCA-301 and the high-affinity Ca2+ probe Fluo-4 upon stimulation by glutamate in stained neurons revealed that KLCA-301 could reflect the secondary large rise of intracellular Ca2+, which Fluo-4 could not detect. In addition, KLCA-501 showed a fluorescence response similar to the low-affinity Ca2+ probe Fluo-5N upon stimulation by glutamate in stained neurons, concluding that KLCA-301 and KLCA-501 could be used as low-affinity Ca2+ probes. The KLCA series offers new options for low-affinity Ca2+ probes. Moreover, KLCA-501 achieved simultaneous visualization of the change in Ca2+ and ATP concentrations and also in mitochondrial inner membrane potential in neurons. KLCA-501 is expected to be a strong tool that enables simultaneous multicolor imaging of multiple targets and elucidation of their relationship in cells.
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Affiliation(s)
- Rei Kumada
- Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Akihiro Sakama
- Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Yutaka Shindo
- Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
- School of Frontier Engineering, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - Yuzuka Kuronuma
- Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Naoko Iwasawa
- Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Daniel Citterio
- Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Kotaro Oka
- Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
- School of Frontier Engineering, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
- Waseda Research Institute for Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan
- College of Medicine, Kaohsiung Medical University, Kaohsiung City 80708, Taiwan
| | - Yuki Hiruta
- Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
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5
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Andreeva VD, Ehlers H, R C AK, Presselt M, J van den Broek L, Bonnet S. Combining nitric oxide and calcium sensing for the detection of endothelial dysfunction. Commun Chem 2023; 6:179. [PMID: 37644120 PMCID: PMC10465535 DOI: 10.1038/s42004-023-00973-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 08/01/2023] [Indexed: 08/31/2023] Open
Abstract
Cardiovascular diseases are the leading cause of death worldwide and are not typically diagnosed until the disease has manifested. Endothelial dysfunction is an early, reversible precursor in the irreversible development of cardiovascular diseases and is characterized by a decrease in nitric oxide production. We believe that more reliable and reproducible methods are necessary for the detection of endothelial dysfunction. Both nitric oxide and calcium play important roles in the endothelial function. Here we review different types of molecular sensors used in biological settings. Next, we review the current nitric oxide and calcium sensors available. Finally, we review methods for using both sensors for the detection of endothelial dysfunction.
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Affiliation(s)
| | - Haley Ehlers
- Mimetas B.V., De limes 7, 2342 DH, Oegstgeest, The Netherlands
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Aswin Krishna R C
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Martin Presselt
- Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Str. 9, 07745, Jena, Germany
- Sciclus GmbH & Co. KG, Moritz-von-Rohr-Str. 1a, 07745, Jena, Germany
| | | | - Sylvestre Bonnet
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands.
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6
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Madar J, Tiwari N, Smith C, Sharma D, Shen S, Elmahdi A, Qiao LY. Piezo2 regulates colonic mechanical sensitivity in a sex specific manner in mice. Nat Commun 2023; 14:2158. [PMID: 37061508 PMCID: PMC10105732 DOI: 10.1038/s41467-023-37683-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 03/27/2023] [Indexed: 04/17/2023] Open
Abstract
The mechanosensitive ion channel Piezo2 in mucosa and primary afferents transduces colonic mechanical sensation. Here we show that chemogenetic activation or nociceptor-targeted deletion of Piezo2 is sufficient to regulate colonic mechanical sensitivity in a sex dependent manner. Clozapine N-oxide-induced activation of Piezo2;hM3Dq-expressing sensory neurons evokes colonic hypersensitivity in male mice, and causes dyspnea in female mice likely due to effects on lung sensory neurons. Activation of Piezo2-expressing colonic afferent neurons also induces colonic hypersensitivity in male but not female mice. Piezo2 levels in nociceptive neurons are higher in female than in male mice. We also show that Piezo2 conditional deletion from nociceptive neurons increases body weight growth, slows colonic transits, and reduces colonic mechanosensing in female but not male mice. Piezo2 deletion blocks colonic hypersensitivity in male but not female mice. These results suggest that Piezo2 in nociceptive neurons mediates innocuous colonic mechanosensing in female mice and painful sensation in male mice, suggesting a sexual dimorphism of Piezo2 function in the colonic sensory system.
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Affiliation(s)
- Jonathan Madar
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Namrata Tiwari
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Cristina Smith
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Divya Sharma
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Shanwei Shen
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Alsiddig Elmahdi
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Liya Y Qiao
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA.
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7
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Dey N. An anthraimidazoledione-based charge transfer probe for dual mode sensing of calcium ions: role of the counter ion in signal improvement. J Mater Chem B 2023; 11:1222-1231. [PMID: 36647619 DOI: 10.1039/d2tb02342c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An anthraimidazoledione-based amphiphilic probe has been designed for dual-mode sensing of Ca2+ ions at physiological pH in a buffered medium. The compound showed deep pink color in the native state due to intramolecular charge transfer from the imidazole to the anthraquinone moiety. The addition of Ca2+ ions resulted changes in solution color to orange with a concomitant appearance of blue-colored fluorescence. The mechanistic investigations indicate that the Ca2+ ion binds to the APTRA moiety on the donor site, which leads to a blue-shift in the absorption maxima. Most importantly, because of the naked-eye response, this method does not need sophisticated visualizing instruments for the analysis. Interestingly, the counter ion showed a significant impact on the extent of Ca2+ sensing. The fluorescence response was large when Cs+ (loose ion pair) was considered as the counter ion instead of K+ (tight ion pair). Furthermore, the present system can achieve the detection of Ca2+ ions in real-life water samples and also in the presence of serum albumin protein. The high recovery values along with small standard deviations indicate the suitability of the present method in analyzing real-life samples. Finally, dye-coated paper strips were developed for rapid, on-location detection of Ca2+ ions.
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Affiliation(s)
- Nilanjan Dey
- Department of Chemistry, Birla Institute of Technology and Science Pilani, Hyderabad, Telangana 500078, India.
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8
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Zajac M, Modi S, Krishnan Y. The evolution of organellar calcium mapping technologies. Cell Calcium 2022; 108:102658. [PMID: 36274564 PMCID: PMC10224794 DOI: 10.1016/j.ceca.2022.102658] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/05/2022] [Accepted: 10/08/2022] [Indexed: 01/25/2023]
Abstract
Intracellular Ca2+ fluxes are dynamically controlled by the co-involvement of multiple organellar pools of stored Ca2+. Endolysosomes are emerging as physiologically critical, yet underexplored, sources and sinks of intracellular Ca2+. Delineating the role of organelles in Ca2+ signaling has relied on chemical fluorescent probes and electrophysiological strategies. However, the acidic endolysosomal environment presents unique issues, which preclude the use of traditional chemical reporter strategies to map lumenal Ca2+. Here, we broadly address the current state of knowledge about organellar Ca2+ pools. We then outline the application of traditional probes, and their sensing paradigms. We then discuss how a new generation of probes overcomes the limitations of traditional Ca2+probes, emphasizing their ability to offer critical insights into endolysosomal Ca2+, and its feedback with other organellar pools.
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Affiliation(s)
- Matthew Zajac
- Department of Chemistry, The University of Chicago, Chicago, Illinois, 60637, USA; Neuroscience Institute, The University of Chicago, Chicago, IL, 60637, USA
| | - Souvik Modi
- Esya Labs, Translation and Innovation Hub, Imperial College White City Campus, 84 Wood Lane, London, W12 0BZ, UK
| | - Yamuna Krishnan
- Department of Chemistry, The University of Chicago, Chicago, Illinois, 60637, USA; Neuroscience Institute, The University of Chicago, Chicago, IL, 60637, USA; Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois, 60637, USA.
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9
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Howe CL, Quicke P, Song P, Verinaz-Jadan H, Dragotti PL, Foust AJ. Comparing synthetic refocusing to deconvolution for the extraction of neuronal calcium transients from light fields. NEUROPHOTONICS 2022; 9:041404. [PMID: 35445141 PMCID: PMC8922050 DOI: 10.1117/1.nph.9.4.041404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Significance: Light-field microscopy (LFM) enables fast, light-efficient, volumetric imaging of neuronal activity with calcium indicators. Calcium transients differ in temporal signal-to-noise ratio (tSNR) and spatial confinement when extracted from volumes reconstructed by different algorithms. Aim: We evaluated the capabilities and limitations of two light-field reconstruction algorithms for calcium fluorescence imaging. Approach: We acquired light-field image series from neurons either bulk-labeled or filled intracellularly with the red-emitting calcium dye CaSiR-1 in acute mouse brain slices. We compared the tSNR and spatial confinement of calcium signals extracted from volumes reconstructed with synthetic refocusing and Richardson-Lucy three-dimensional deconvolution with and without total variation regularization. Results: Both synthetic refocusing and Richardson-Lucy deconvolution resolved calcium signals from single cells and neuronal dendrites in three dimensions. Increasing deconvolution iteration number improved spatial confinement but reduced tSNR compared with synthetic refocusing. Volumetric light-field imaging did not decrease calcium signal tSNR compared with interleaved, widefield image series acquired in matched planes. Conclusions: LFM enables high-volume rate, volumetric imaging of calcium transients in single cell somata (bulk-labeled) and dendrites (intracellularly loaded). The trade-offs identified for tSNR, spatial confinement, and computational cost indicate which of synthetic refocusing or deconvolution can better realize the scientific requirements of future LFM calcium imaging applications.
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Affiliation(s)
- Carmel L. Howe
- Imperial College London, Department of Bioengineering, London, United Kingdom
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
| | - Peter Quicke
- Imperial College London, Department of Bioengineering, London, United Kingdom
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
| | - Pingfan Song
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
- Imperial College London, Department of Electrical and Electronic Engineering, London, United Kingdom
| | - Herman Verinaz-Jadan
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
- Imperial College London, Department of Electrical and Electronic Engineering, London, United Kingdom
| | - Pier Luigi Dragotti
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
- Imperial College London, Department of Electrical and Electronic Engineering, London, United Kingdom
| | - Amanda J. Foust
- Imperial College London, Department of Bioengineering, London, United Kingdom
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
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10
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Junge S, Schmieder F, Sasse P, Czarske J, Torres-Mapa ML, Heisterkamp A. Holographic optogenetic stimulation with calcium imaging as an all optical tool for cardiac electrophysiology. JOURNAL OF BIOPHOTONICS 2022; 15:e202100352. [PMID: 35397155 DOI: 10.1002/jbio.202100352] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/25/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
All optical approaches to control and read out the electrical activity in a cardiac syncytium can improve our understanding of cardiac electrophysiology. Here, we demonstrate optogenetic stimulation of cardiomyocytes with high spatial precision using light foci generated with a ferroelectric spatial light modulator. Computer generated holograms binarized by bidirectional error diffusion create multiple foci with more even intensity distribution compared with thresholding approach. We evoke the electrical activity of cardiac HL1 cells expressing the channelrhodopsin-2 variant, ChR2(H134R) using single and multiple light foci and at the same time visualize the action potential using a calcium sensitive indicator called Cal-630. We show that localized regions in the cardiac monolayer can be stimulated enabling us to initiate signal propagation from a precise location. Furthermore, we demonstrate that probing the cardiac cells with multiple light foci enhances the excitability of the cardiac network. This approach opens new applications in manipulating and visualizing the electrical activity in a cardiac syncytium.
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Affiliation(s)
- Sebastian Junge
- Institute of Quantum Optics, Gottfried Wilhelm Leibniz University, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Felix Schmieder
- Faculty of Electrical and Computer Engineering, Laboratory of Measurement and Sensor System Technique and Competence Center Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Dresden, Germany
| | - Philipp Sasse
- Medical Faculty, Institute of Physiology I, University of Bonn, Bonn, Germany
| | - Jürgen Czarske
- Faculty of Electrical and Computer Engineering, Laboratory of Measurement and Sensor System Technique and Competence Center Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Dresden, Germany
- Faculty of Physics, School of Science and Excellence Cluster Physics of Life, TU Dresden, Dresden, Germany
| | - Maria Leilani Torres-Mapa
- Institute of Quantum Optics, Gottfried Wilhelm Leibniz University, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Alexander Heisterkamp
- Institute of Quantum Optics, Gottfried Wilhelm Leibniz University, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
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11
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Bachollet SPJT, Pietrancosta N, Mallet JM, Dumat B. Fluorogenic and genetic targeting of a red-emitting molecular calcium indicator. Chem Commun (Camb) 2022; 58:6594-6597. [PMID: 35593406 DOI: 10.1039/d2cc01792j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We introduce a strategy for the fluorogenic and genetic targeting of a calcium indicator by combining a protein fluorogen with the BAPTA sensing group. The resulting dual-input probe acts like a fluorescent AND logic gate with a Ca2+-sensitive red emission that is activated only upon reaction with HaloTag with a 25-fold intensity enhancement and can be used for wash-free calcium imaging in HeLa cells. The modular all-molecular design relying on a well-established self-labeling protein tag opens future possibilities for tuning the photophysical properties or targeting different analytes.
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Affiliation(s)
- Sylvestre P J T Bachollet
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Nicolas Pietrancosta
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France. .,Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS) INSERM, CNRS, Sorbonne Université, Paris, France
| | - Jean-Maurice Mallet
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Blaise Dumat
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
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12
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Holmes J, Sushma AA, Tsvetkova IB, Schaich WL, Schaller RD, Dragnea B. Ultrafast Collective Excited-State Dynamics of a Virus-Supported Fluorophore Antenna. J Phys Chem Lett 2022; 13:3237-3243. [PMID: 35380843 PMCID: PMC9306353 DOI: 10.1021/acs.jpclett.2c00262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Radiation brightening was recently observed in a multifluorophore-conjugated brome mosaic virus (BMV) particle at room temperature under pulsed excitation. On the basis of its nonlinear dependence on the number of chromophores, the origins of the phenomenon were attributed to a collective relaxation. However, the mechanism remains unknown. We present ultrafast transient absorption and fluorescence spectroscopic studies which shed new light on the collective nature of the relaxation dynamics in such radiation-brightened, multifluorophore particles. Our findings indicate that the emission dynamics is consistent with a superradiance mechanism. The ratio between the rates of competing radiative and nonradiative relaxation pathways depends on the number of chromophores per virus. The findings suggest that small icosahedral virus shells provide a unique biological scaffold for developing nonclassical, deep subwavelength light sources and may open new avenues for the development of photonic probes for medical imaging applications.
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Affiliation(s)
- Joseph Holmes
- Physics Department, Indiana University, Bloomington, Indiana 47405, United States
| | - Arathi Anil Sushma
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Irina B Tsvetkova
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - William L Schaich
- Physics Department, Indiana University, Bloomington, Indiana 47405, United States
| | - Richard D Schaller
- The Center for Nanoscale Materials at Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Bogdan Dragnea
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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13
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Mertes N, Busch M, Huppertz MC, Hacker CN, Wilhelm J, Gürth CM, Kühn S, Hiblot J, Koch B, Johnsson K. Fluorescent and Bioluminescent Calcium Indicators with Tuneable Colors and Affinities. J Am Chem Soc 2022; 144:6928-6935. [PMID: 35380808 PMCID: PMC9026248 DOI: 10.1021/jacs.2c01465] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
We introduce a family
of bright, rhodamine-based calcium indicators
with tuneable affinities and colors. The indicators can be specifically
localized to different cellular compartments and are compatible with
both fluorescence and bioluminescence readouts through conjugation
to HaloTag fusion proteins. Importantly, their increase in fluorescence
upon localization enables no-wash live-cell imaging, which greatly
facilitates their use in biological assays. Applications as fluorescent
indicators in rat hippocampal neurons include the detection of single
action potentials and of calcium fluxes in the endoplasmic reticulum.
Applications as bioluminescent indicators include the recording of
the pharmacological modulation of nuclear calcium in high-throughput
compatible assays. The versatility and remarkable ease of use of these
indicators make them powerful tools for bioimaging and bioassays.
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Affiliation(s)
- Nicole Mertes
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Marvin Busch
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Magnus-Carsten Huppertz
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Christina Nicole Hacker
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Jonas Wilhelm
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Clara-Marie Gürth
- Department of Optical Nanoscopy, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Stefanie Kühn
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Julien Hiblot
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Birgit Koch
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Kai Johnsson
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.,Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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14
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Kronfeld K, Ellinger T, Köhler JM. Micro flow photochemical synthesis of Ca-sensitive fluorescent sensor particles. Eng Life Sci 2021; 21:518-526. [PMID: 34584516 PMCID: PMC8456324 DOI: 10.1002/elsc.202100023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/08/2021] [Accepted: 05/25/2021] [Indexed: 12/27/2022] Open
Abstract
Fluorescence probes have widely been used for detecting and imaging Ca2+-enriched parts of cells but more rarely for quantitative determination of concentrations. In this study we show how this can be achieved by a novel approach using hydrogel particles. In a microfluidic co-flow arrangement spherical droplets were generated from an aqueous solution of acrylamide, N,N'-methylenebisacrylamide crosslinker and photoinitiator and subsequently photo-cured in situ yielding gel particles in a sub millimeter range. These particles were separated, dried under reduced pressure and re-swollen in water containing Rhod-5N tri potassium salt as calcium ion selective fluorescence probe. After that the particles were dried again and stored for further investigations. Upon exposure of dried particles to calcium chloride solutions they swell and take up Ca2+-ions forming a strong fluorescing complex with Rhod-5N. Thus, fluorescence intensity increases with calcium ion concentration. Up to ca. 0.50 mM the enhancement effect is strong and then becomes considerably weaker. The intensity-concentration-dependence is well described by an equation derived from the equilibrium of the formation of a 1:1 Ca2+:Rhod-5N complex. The particles allow for a fast optical determination of Ca2+-concentrations up to 0.50 mM in analyte volumes down to below 10 μL.
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Affiliation(s)
- Klaus‐Peter Kronfeld
- Department of Physical Chemistry and Microreaction TechnologyTechnical University IlmenauIlmenauGermany
| | | | - Johann Michael Köhler
- Department of Physical Chemistry and Microreaction TechnologyTechnical University IlmenauIlmenauGermany
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15
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Zhou X, Belavek KJ, Miller EW. Origins of Ca 2+ Imaging with Fluorescent Indicators. Biochemistry 2021; 60:3547-3554. [PMID: 34251789 DOI: 10.1021/acs.biochem.1c00350] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In 1980, Roger Tsien published a paper, in this journal [Tsien, R. Y. (1980) Biochemistry, 19 (11), 2396], titled "New calcium indicators and buffers with high selectivity against magnesium and protons: design, synthesis, and properties of prototype structures". These new buffers included 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, or BAPTA, which is still widely used today. And so, the world was set alight with new ways in which to visualize Ca2+. The ability to watch fluctuations in intracellular Ca2+ revolutionized the life sciences, although the fluorescent indicators used today, particularly in neurobiology, no longer rely exclusively on BAPTA but on genetically encoded fluorescent Ca2+ indicators. In this Perspective, we reflect on the origins of Ca2+ imaging with a special focus on the contributions made by Roger Tsien, from the early concept of selective Ca2+ binding described in Biochemistry to optical Ca2+ indicators based on chemically synthesized fluorophores to genetically encoded fluorescent Ca2+ indicators.
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16
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Calvo-Rodriguez M, Kharitonova EK, Bacskai BJ. In vivo brain imaging of mitochondrial Ca 2+ in neurodegenerative diseases with multiphoton microscopy. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2021; 1868:118998. [PMID: 33684410 PMCID: PMC8057769 DOI: 10.1016/j.bbamcr.2021.118998] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/22/2021] [Indexed: 10/22/2022]
Abstract
Mitochondria are involved in a large number of essential roles related to neuronal function. Ca2+ handling by mitochondria is critical for many of these functions, including energy production and cellular fate. Conversely, mitochondrial Ca2+ mishandling has been related to a variety of neurodegenerative diseases. Investigating mitochondrial Ca2+ dynamics is essential for advancing our understanding of the role of intracellular mitochondrial Ca2+ signals in physiology and pathology. Improved Ca2+ indicators, and the ability to target them to different cells and compartments, have emerged as useful tools for analysis of Ca2+ signals in living organisms. Combined with state-of-the-art techniques such as multiphoton microscopy, they allow for the study of mitochondrial Ca2+ dynamics in vivo in mouse models of the disease. Here, we provide an overview of the Ca2+ transporters/ion channels in mitochondrial membranes, and the involvement of mitochondrial Ca2+ in neurodegenerative diseases followed by a summary of the main tools available to evaluate mitochondrial Ca2+ dynamics in vivo using the aforementioned technique.
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Affiliation(s)
- Maria Calvo-Rodriguez
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114, 16th St, Charlestown, MA, 02129, USA.
| | - Elizabeth K Kharitonova
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114, 16th St, Charlestown, MA, 02129, USA
| | - Brian J Bacskai
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114, 16th St, Charlestown, MA, 02129, USA
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17
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Özçete ÖD, Moser T. A sensory cell diversifies its output by varying Ca 2+ influx-release coupling among active zones. EMBO J 2020; 40:e106010. [PMID: 33346936 PMCID: PMC7917556 DOI: 10.15252/embj.2020106010] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023] Open
Abstract
The cochlea encodes sound pressures varying over six orders of magnitude by collective operation of functionally diverse spiral ganglion neurons (SGNs). The mechanisms enabling this functional diversity remain elusive. Here, we asked whether the sound intensity information, contained in the receptor potential of the presynaptic inner hair cell (IHC), is fractionated via heterogeneous synapses. We studied the transfer function of individual IHC synapses by combining patch‐clamp recordings with dual‐color Rhod‐FF and iGluSnFR imaging of presynaptic Ca2+ signals and glutamate release. Synapses differed in the voltage dependence of release: Those residing at the IHC' pillar side activated at more hyperpolarized potentials and typically showed tight control of release by few Ca2+ channels. We conclude that heterogeneity of voltage dependence and release site coupling of Ca2+ channels among the synapses varies synaptic transfer within individual IHCs and, thereby, likely contributes to the functional diversity of SGNs. The mechanism reported here might serve sensory cells and neurons more generally to diversify signaling even in close‐by synapses.
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Affiliation(s)
- Özge D Özçete
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Göttingen Graduate Center for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Göttingen Graduate Center for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute of Biophysical Chemistry, Göttingen, Germany.,Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, Göttingen, Germany
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18
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Schwarze T, Sprenger T, Riemer J. 1,2,3‐Triazol‐1,4‐diyl‐Fluoroionophores for Zn 2+, Mg 2+and Ca 2+based on Fluorescence Intensity Enhancements in Water. ChemistrySelect 2020. [DOI: 10.1002/slct.202003695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Thomas Schwarze
- Institut für Chemie, Anorganische Chemie Universität Potsdam Karl-Liebknecht-Str. 24–25 14476 Golm Germany
| | - Tobias Sprenger
- Institut für Chemie, Anorganische Chemie Universität Potsdam Karl-Liebknecht-Str. 24–25 14476 Golm Germany
| | - Janine Riemer
- Institut für Chemie, Anorganische Chemie Universität Potsdam Karl-Liebknecht-Str. 24–25 14476 Golm Germany
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19
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Abstract
Rod photoreceptors are composed of a soma and an inner segment (IS) connected to an outer segment (OS) by a thin cilium. OSs are composed of a stack of ∼800 lipid discs surrounded by the plasma membrane where phototransduction takes place. Intracellular calcium plays a major role in phototransduction and is more concentrated in the discs, where it can be incorporated and released. To study calcium dynamics in rods, we used the fluorescent calcium dye CaSiR-1 AM working in the near-infrared (NIR) (excitation at 650 and emission at 664 nm), an advantage over previously used dyes. In this way, we investigated calcium dynamics with an unprecedented accuracy and most importantly in semidark-adapted conditions. We observed light-induced drops in [Ca2+]i with kinetics similar to that of photoresponses recorded electrophysiologically. We show three properties of the rods. First, intracellular calcium and key proteins have concentrations that vary from the OS base to tip. At the OS base, [Ca2+]i is ∼80 nM and increases up to ∼200 nM at the OS tip. Second, there are spontaneous calcium flares in healthy and functional rod OSs; these flares are highly localized and are more pronounced at the OS tip. Third, a bright flash of light at 488 nm induces a drop in [Ca2+]i at the OS base but often a flare at the OS tip. Therefore, rod OSs are not homogenous structures but have a structural and functional gradient, which is a fundamental aspect of transduction in vertebrate photoreceptors.
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20
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Pang S. A novel colorimetric assay for calcium ion and calmodulin detection based on gold nanoparticles. INORG NANO-MET CHEM 2020. [DOI: 10.1080/24701556.2020.1802753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Shu Pang
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun, China
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21
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Sensing Senses: Optical Biosensors to Study Gustation. SENSORS 2020; 20:s20071811. [PMID: 32218129 PMCID: PMC7180777 DOI: 10.3390/s20071811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/19/2020] [Accepted: 03/21/2020] [Indexed: 12/11/2022]
Abstract
The five basic taste modalities, sweet, bitter, umami, salty and sour induce changes of Ca2+ levels, pH and/or membrane potential in taste cells of the tongue and/or in neurons that convey and decode gustatory signals to the brain. Optical biosensors, which can be either synthetic dyes or genetically encoded proteins whose fluorescence spectra depend on levels of Ca2+, pH or membrane potential, have been used in primary cells/tissues or in recombinant systems to study taste-related intra- and intercellular signaling mechanisms or to discover new ligands. Taste-evoked responses were measured by microscopy achieving high spatial and temporal resolution, while plate readers were employed for higher throughput screening. Here, these approaches making use of fluorescent optical biosensors to investigate specific taste-related questions or to screen new agonists/antagonists for the different taste modalities were reviewed systematically. Furthermore, in the context of recent developments in genetically encoded sensors, 3D cultures and imaging technologies, we propose new feasible approaches for studying taste physiology and for compound screening.
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22
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Takahashi S, Hanaoka K, Okubo Y, Echizen H, Ikeno T, Komatsu T, Ueno T, Hirose K, Iino M, Nagano T, Urano Y. Rational Design of a Near-infrared Fluorescence Probe for Ca 2+ Based on Phosphorus-substituted Rhodamines Utilizing Photoinduced Electron Transfer. Chem Asian J 2020; 15:524-530. [PMID: 31909880 DOI: 10.1002/asia.201901689] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Indexed: 12/12/2022]
Abstract
Fluorescence imaging in the near-infrared (NIR) region (650-900 nm) is useful for bioimaging because background autofluorescence is low and tissue penetration is high in this range. In addition, NIR fluorescence is useful as a complementary color window to green and red for multicolor imaging. Here, we compared the photoinduced electron transfer (PeT)-mediated fluorescence quenching of silicon- and phosphorus-substituted rhodamines (SiRs and PRs) in order to guide the development of improved far-red to NIR fluorescent dyes. The results of density functional theory calculations and photophysical evaluation of a series of newly synthesized PRs confirmed that the fluorescence of PRs was more susceptible than that of SiRs to quenching via PeT. Based on this, we designed and synthesized a NIR fluorescence probe for Ca2+ , CaPR-1, and its membrane-permeable acetoxymethyl derivative, CaPR-1 AM, which is distributed to the cytosol, in marked contrast to our previously reported Ca2+ far-red to NIR fluorescence probe based on the SiR scaffold, CaSiR-1 AM, which is mainly localized in lysosomes as well as cytosol in living cells. CaPR-1 showed longer-wavelength absorption and emission (up to 712 nm) than CaSiR-1. The new probe was able to image Ca2+ at dendrites and spines in brain slices, and should be a useful tool in neuroscience research.
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Affiliation(s)
- Shodai Takahashi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Kenjiro Hanaoka
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yohei Okubo
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Honami Echizen
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Takayuki Ikeno
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Toru Komatsu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Tasuku Ueno
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Kenzo Hirose
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masamitsu Iino
- Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, 30-1 Oyaguchi kamicho, Itabashi-ku, Tokyo, 173-8610, Japan
| | - Tetsuo Nagano
- Drug Discovery Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yasuteru Urano
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Laboratory of Chemical Biology and Molecular Imaging, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,AMED-CREST, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo, 100-0004, Japan
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23
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Numasawa K, Hanaoka K, Ikeno T, Echizen H, Ishikawa T, Morimoto M, Komatsu T, Ueno T, Ikegaya Y, Nagano T, Urano Y. A cytosolically localized far-red to near-infrared rhodamine-based fluorescent probe for calcium ions. Analyst 2020; 145:7736-7740. [DOI: 10.1039/d0an01739f] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We developed the cytosolically localized far-red to NIR fluorescent probe for Ca2+,CaSiR-2 AM, utilizing the rhodamine scaffold.
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24
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Hua Y, Wei Q, Wu G, Sun ZB, Shang YJ. Fluorescent Determination of Calcium Ion Using a Coumarinyl Pyrazoline Scaffold and Its Application in Living Cells. ANAL LETT 2019. [DOI: 10.1080/00032719.2019.1687508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Yun Hua
- Department of Chemistry, College of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, China
| | - Qiang Wei
- Department of Chemistry, College of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, China
| | - Gang Wu
- Zhoulu Middle School No. 2, Zhangjiakou, China
| | - Zhi-Bin Sun
- Department of Chemistry, College of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, China
| | - Ya-Jing Shang
- Department of Chemistry, College of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, China
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25
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Deo C, Sheu SH, Seo J, Clapham DE, Lavis LD. Isomeric Tuning Yields Bright and Targetable Red Ca2+ Indicators. J Am Chem Soc 2019; 141:13734-13738. [DOI: 10.1021/jacs.9b06092] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Claire Deo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, United States
| | - Shu-Hsien Sheu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, United States
| | - Jinyoung Seo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, United States
| | - David E. Clapham
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, United States
| | - Luke D. Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, United States
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26
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Wang L, Yao Y, Wang J, Dong C, Han H. Selective sensing Ca
2+
with a spiropyran‐based fluorometric probe. LUMINESCENCE 2019; 34:707-714. [DOI: 10.1002/bio.3656] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 05/07/2019] [Accepted: 05/10/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Li Wang
- Institute of Environmental ScienceShanxi University Taiyuan 030006 China
| | - Yuanjun Yao
- School of Chemistry and Chemical EngineeringShanxi University Taiyuan 030006 China
| | - Jiao Wang
- School of Chemistry and Chemical EngineeringShanxi University Taiyuan 030006 China
| | - Chuan Dong
- Institute of Environmental ScienceShanxi University Taiyuan 030006 China
| | - Hui Han
- Institute of Environmental ScienceShanxi University Taiyuan 030006 China
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27
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State-of-the-art: functional fluorescent probes for bioimaging and pharmacological research. Acta Pharmacol Sin 2019; 40:717-723. [PMID: 30487651 DOI: 10.1038/s41401-018-0190-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/19/2018] [Indexed: 12/14/2022] Open
Abstract
Cardiovascular diseases, neuropsychiatric disorders, and cancers seriously endanger human health. Mechanistic and pharmacological mechanisms of candidate drugs are central to the translational paradigm. Since many signal transduction and molecular events are implicated in these diseases, a novel method to interrogate the key pharmacological mechanisms is required to accelerate innovative drug discovery. Much attention now focuses on the real-time visualization of molecular disease events to yield new insights to the pathogenesis of the diseases. This review focuses on recent advances in the development of chemical probes for imaging pathological events to facilitate the study of the underlying pharmacodynamics and toxicity involved. As reviewed here, optical imaging is now frequently viewed as an indispensable technique in the field of biological research. Promoting interdisciplinary collaboration among chemistry, biology and medicine, is necessary to further refine functional fluorescent probes for diagnostic and therapeutic applications.
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28
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Liu Z, Pei H, Zhang L, Tian Y. Mitochondria-Targeted DNA Nanoprobe for Real-Time Imaging and Simultaneous Quantification of Ca 2+ and pH in Neurons. ACS NANO 2018; 12:12357-12368. [PMID: 30418752 DOI: 10.1021/acsnano.8b06322] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Herein, a single highly selective DNA nanoprobe was designed and created for the real-time imaging and simultaneous quantification of two kinds of biological species using Ca2+ and pH; the molecules were selected as models because of their close relationship with cellular functions and diseases. A Ca2+ fluorescent probe was synthesized and assembled onto a DNA nanostructure together with pH-responsive, inner-reference, and mitochondria-targeted molecules. This nanoprobe with high spatial resolution, together with long-term fluorescent and structural stability, powerfully tracked pH and Ca2+ dynamics at the same localization in mitochondria in response to O2•--induced oxidative stress and aggregated amyloid β (Aβ) stimulation with a temporal resolution of milliseconds. Using this tool, we discovered that O2•- and Aβ triggered transitory cytoplasmic acidosis and then activated acid-sensing ion channel 1a (ASIC1a) in the mitochondrial membrane, leading to mitochondrial Ca2+ overload and pH abnormalities, which contribute to neuron death. Moreover, psalmotoxin 1 effectively protected against O2•-- and Aβ-induced neuron injury.
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Affiliation(s)
- Zhichao Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering , East China Normal University , Dongchuan Road 500 , Shanghai 200241 , China
| | - Hao Pei
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering , East China Normal University , Dongchuan Road 500 , Shanghai 200241 , China
| | - Limin Zhang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering , East China Normal University , Dongchuan Road 500 , Shanghai 200241 , China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering , East China Normal University , Dongchuan Road 500 , Shanghai 200241 , China
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29
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Pimenta S, Pereira JP, Gomes NM, Ribeiro JF, Silva MF, Goncalves SB, Minas G, Correia JH. High-selectivity neural probe based on a Fabry-Perot optical filter and a CMOS silicon photodiodes array at visible wavelengths. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-7. [PMID: 30350488 DOI: 10.1117/1.jbo.23.10.105004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/25/2018] [Indexed: 06/08/2023]
Abstract
This paper presents a silicon neural probe with a high-selectivity optical readout function and light emitting diodes for neurons photostimulation and fluorophore excitation. A high-selectivity Fabry-Perot optical filter on the top of a CMOS silicon photodiodes array can read the emitted fluorescence, which indicates the neurons physiological state. The design, fabrication, and characterization of the optical filter are presented. The SiO2 / TiO2 based optical filter thin films were deposited by RF sputtering. The performance of the optical filter deposited on the top of the silicon photodiodes array, implemented in the neural probe, was tested through in-vitro fluorescence measurements. The transmittance peak of the fabricated optical filter is 81.8% at 561 nm, with a full width at half maximum of 28 nm. The peak responsivity of the CMOS silicon photodiode with the optical filter deposited on its top is 273.6 mA / W at 578 nm. The in-vitro fluorescence measurements results show a CMOS photodiode current proportional to the fluorophore concentration with a good linearity (R2 = 0.9361). The results validate the use of the neural probe with the high-selectivity optical readout function to determine the presence of different fluorophore concentrations. The development of the device in a conventional CMOS process allows on-chip electronics readout.
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Affiliation(s)
- Sara Pimenta
- University of Minho, CMEMS-UMinho, Campus de Azurém, Guimarães, Portugal
| | - José P Pereira
- University of Minho, CMEMS-UMinho, Campus de Azurém, Guimarães, Portugal
| | - Nuno M Gomes
- University of Minho, CMEMS-UMinho, Campus de Azurém, Guimarães, Portugal
| | - João F Ribeiro
- University of Minho, CMEMS-UMinho, Campus de Azurém, Guimarães, Portugal
| | - Manuel F Silva
- University of Minho, CMEMS-UMinho, Campus de Azurém, Guimarães, Portugal
| | - Sandra B Goncalves
- University of Minho, CMEMS-UMinho, Campus de Azurém, Guimarães, Portugal
| | - Graca Minas
- University of Minho, CMEMS-UMinho, Campus de Azurém, Guimarães, Portugal
| | - José H Correia
- University of Minho, CMEMS-UMinho, Campus de Azurém, Guimarães, Portugal
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30
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Gao M, Li Y, Chen X, Li S, Ren L, Tang BZ. Aggregation-Induced Emission Probe for Light-Up and in Situ Detection of Calcium Ions at High Concentration. ACS APPLIED MATERIALS & INTERFACES 2018; 10:14410-14417. [PMID: 29671572 DOI: 10.1021/acsami.8b00952] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The fluorescent probe for the detection of calcium ions is an indispensable tool in the biomedical field. The millimolar order of Ca(II) ions is associated with many physiological processes and diseases, such as hypercalcemia, soft tissue calcification, and bone microcracks. However, the conventional fluorescent probes are only suitable for imaging Ca(II) ions in the nanomolar to micromolar range, which can be because of their high affinities toward Ca(II) ions and aggregation-caused quenching drawbacks. To tackle this challenge, we herein develop an aggregation-induced emission (AIE) probe SA-4CO2Na for selective and light-up detection of Ca(II) ions in the millimolar range (0.6-3.0 mM), which can efficiently distinguish between hypercalcemic (1.4-3.0 mM) and normal (1.0-1.4 mM) Ca2+ ion levels. The formation of fibrillar aggregates between SA-4CO2Na and Ca(II) ions was clearly verified by fluorescence, scanning electron microscopy, and transmission electron analysis. Moreover, this AIE-active probe can be used for wash-free and light-up imaging of a high concentration of Ca(II) ions even in the solid analytes, including calcium deposits in psammomatous meningioma slice, microcracks on bovine bone surface, and microdefects on hydroxyapatite-based scaffold. It is thus expected that this AIE-active probe would have broad biomedical applications through light-up imaging and sensing of Ca(II) ions at the millimolar level.
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Affiliation(s)
- Meng Gao
- National Engineering Research Center for Tissue Restoration and Reconstruction , South China University of Technology , Guangzhou 510006 , China
| | - Yunxia Li
- National Engineering Research Center for Tissue Restoration and Reconstruction , South China University of Technology , Guangzhou 510006 , China
| | - Xiaohui Chen
- National Engineering Research Center for Tissue Restoration and Reconstruction , South China University of Technology , Guangzhou 510006 , China
| | | | - Li Ren
- National Engineering Research Center for Tissue Restoration and Reconstruction , South China University of Technology , Guangzhou 510006 , China
| | - Ben Zhong Tang
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction , The Hong Kong University of Science & Technology , Clear Water Bay, Kowloon , Hong Kong, China
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31
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Ravi B, Nassar LM, Kopchock RJ, Dhakal P, Scheetz M, Collins KM. Ratiometric Calcium Imaging of Individual Neurons in Behaving Caenorhabditis Elegans. J Vis Exp 2018. [PMID: 29443112 PMCID: PMC5912386 DOI: 10.3791/56911] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
It has become increasingly clear that neural circuit activity in behaving animals differs substantially from that seen in anesthetized or immobilized animals. Highly sensitive, genetically encoded fluorescent reporters of Ca2+ have revolutionized the recording of cell and synaptic activity using non-invasive optical approaches in behaving animals. When combined with genetic and optogenetic techniques, the molecular mechanisms that modulate cell and circuit activity during different behavior states can be identified. Here we describe methods for ratiometric Ca2+ imaging of single neurons in freely behaving Caenorhabditis elegans worms. We demonstrate a simple mounting technique that gently overlays worms growing on a standard Nematode Growth Media (NGM) agar block with a glass coverslip, permitting animals to be recorded at high-resolution during unrestricted movement and behavior. With this technique, we use the sensitive Ca2+ reporter GCaMP5 to record changes in intracellular Ca2+ in the serotonergic Hermaphrodite Specific Neurons (HSNs) as they drive egg-laying behavior. By co-expressing mCherry, a Ca2+-insensitive fluorescent protein, we can track the position of the HSN within ~ 1 µm and correct for fluctuations in fluorescence caused by changes in focus or movement. Simultaneous, infrared brightfield imaging allows for behavior recording and animal tracking using a motorized stage. By integrating these microscopic techniques and data streams, we can record Ca2+ activity in the C. elegans egg-laying circuit as it progresses between inactive and active behavior states over tens of minutes.
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Affiliation(s)
- Bhavya Ravi
- Neuroscience Program, University of Miami School of Medicine
| | - Layla M Nassar
- Neuroscience Program, University of Miami School of Medicine; Department of Biology, University of Miami
| | | | | | | | - Kevin M Collins
- Neuroscience Program, University of Miami School of Medicine; Department of Biology, University of Miami;
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32
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Carr L, Bardet SM, Arnaud-Cormos D, Leveque P, O'Connor RP. Visualisation of an nsPEF induced calcium wave using the genetically encoded calcium indicator GCaMP in U87 human glioblastoma cells. Bioelectrochemistry 2018; 119:68-75. [DOI: 10.1016/j.bioelechem.2017.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/23/2017] [Accepted: 09/07/2017] [Indexed: 12/21/2022]
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33
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Abstract
Ca2+ mediates a host of biochemical and biophysical signaling processes in cells. The development of synthetic, Ca2+-sensitive fluorophores has played an instrumental role in our understanding of the temporal and spatial dynamics of Ca2+. Coupling Ca2+-selective ligands to fluorescent reporters has provided a wealth of excellent indicators that span the visible excitation and emission spectrum and possess Ca2+ affinities suited to a variety of cellular contexts. One underdeveloped area is the use of hybrid rhodamine/fluorescein fluorophores, or rhodols, in the context of Ca2+ sensing. Rhodols are bright and photostable and have good two-photon absorption cross sections (σTPA), making them excellent candidates for incorporation into Ca2+-sensing scaffolds. Here, we present the design, synthesis, and application of rhodol Ca2+ sensor 1 (RCS-1), a chlorinated pyrrolidine-based rhodol. RCS-1 possesses a Ca2+ binding constant of 240 nM and a 10-fold turn response to Ca2+. RCS-1 effectively absorbs infrared light and has a σTPA of 76 GM at 840 nm, 3-fold greater than that of its fluorescein-based counterpart. The acetoxy-methyl ester of RCS-1 stains the cytosol of live cells, enabling observation of Ca2+ fluctuations and cultured neurons using both one- and two-photon illumination. Together, these results demonstrate the utility of rhodol-based scaffolds for Ca2+ sensing using two-photon illumination in neurons.
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Affiliation(s)
- Alisha A Contractor
- Department of Chemistry, ‡Department of Molecular and Cell Biology, and §Helen Wills Neuroscience Institute, University of California , Berkeley, California 94720, United States
| | - Evan W Miller
- Department of Chemistry, ‡Department of Molecular and Cell Biology, and §Helen Wills Neuroscience Institute, University of California , Berkeley, California 94720, United States
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34
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Ponsot F, Shen W, Ashokkumar P, Audinat E, Klymchenko AS, Collot M. PEGylated Red-Emitting Calcium Probe with Improved Sensing Properties for Neuroscience. ACS Sens 2017; 2:1706-1712. [PMID: 29019233 DOI: 10.1021/acssensors.7b00665] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Monitoring calcium concentration in the cytosol is of main importance as this ion drives many biological cascades within the cell. To this end, molecular calcium probes are widely used. Most of them, especially the red emitting probes, suffer from nonspecific interactions with inner membranes due to the hydrophobic nature of their fluorophore. To circumvent this issue, calcium probes conjugated to dextran can be used to enhance the hydrophilicity and reduce the nonspecific interaction and compartmentalization. However, dextran conjugates also feature important drawbacks including lower affinity, lower dynamic range, and slow diffusion. Herein, we combined the advantage of molecular probes and dextran conjugate without their drawbacks by designing a new red emitting turn-on calcium probe based on PET quenching, Rhod-PEG, in which the rhodamine fluorophore bears four PEG4 units. This modification led to a high affinity calcium probe (Kd = 748 nM) with reduced nonspecific interactions, enhanced photostability, two-photon absorbance, and brightness compared to the commercially available Rhod-2. After spectral characterizations, we showed that Rhod-PEG quickly and efficiently diffused through the dendrites of pyramidal neurons with an enhanced sensitivity (ΔF/F0) at shorter time after patching compared to Rhod-2.
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Affiliation(s)
- Flavien Ponsot
- Laboratoire
de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74, Route du Rhin, 67401, Illkirch, France
| | - Weida Shen
- INSERM, U1128, Paris, France
- Laboratory
of Neurophysiology and New Microscopies, Paris Descartes University, 75006 Paris, France
| | - Pichandi Ashokkumar
- Laboratoire
de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74, Route du Rhin, 67401, Illkirch, France
| | - Etienne Audinat
- INSERM, U1128, Paris, France
- Laboratory
of Neurophysiology and New Microscopies, Paris Descartes University, 75006 Paris, France
| | - Andrey S. Klymchenko
- Laboratoire
de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74, Route du Rhin, 67401, Illkirch, France
| | - Mayeul Collot
- Laboratoire
de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74, Route du Rhin, 67401, Illkirch, France
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35
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New EJ, Wimmer VC, Hare DJ. Promises and Pitfalls of Metal Imaging in Biology. Cell Chem Biol 2017; 25:7-18. [PMID: 29153850 DOI: 10.1016/j.chembiol.2017.10.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/02/2017] [Accepted: 10/18/2017] [Indexed: 10/18/2022]
Abstract
A picture may speak a thousand words, but if those words fail to form a coherent sentence there is little to be learned. As cutting-edge imaging technology now provides us the tools to decipher the multitude of roles played by metals and metalloids in molecular, cellular, and developmental biology, as well as health and disease, it is time to reflect on the advances made in imaging, the limitations discovered, and the future of a burgeoning field. In this Perspective, the current state of the art is discussed from a self-imposed contrarian position, as we not only highlight the major advances made over the years but use them as teachable moments to zoom in on challenges that remain to be overcome. We also describe the steps being taken toward being able to paint a completely undisturbed picture of cellular metal metabolism, which is, metaphorically speaking, the Holy Grail of the discipline.
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Affiliation(s)
- Elizabeth J New
- School of Chemistry, The University of Sydney, Camperdown, NSW 2006, Australia
| | - Verena C Wimmer
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Dominic J Hare
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3052, Australia; Elemental Bio-imaging Facility, University of Technology Sydney, Broadway, NSW 2007, Australia; Department of Pathology, The University of Melbourne, Parkville, VIC 3052, Australia.
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36
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Roberts S, Seeger M, Jiang Y, Mishra A, Sigmund F, Stelzl A, Lauri A, Symvoulidis P, Rolbieski H, Preller M, Deán-Ben XL, Razansky D, Orschmann T, Desbordes SC, Vetschera P, Bach T, Ntziachristos V, Westmeyer GG. Calcium Sensor for Photoacoustic Imaging. J Am Chem Soc 2017; 140:2718-2721. [DOI: 10.1021/jacs.7b03064] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Matthias Preller
- CSSB,
22607 Hamburg and Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
| | | | | | | | | | | | - Thorsten Bach
- Department
Chemie, Technical University of Munich, 85747 Garching, Germany
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37
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Fontaine AK, Gibson EA, Caldwell JH, Weir RF. Optical Read-out of Neural Activity in Mammalian Peripheral Axons: Calcium Signaling at Nodes of Ranvier. Sci Rep 2017; 7:4744. [PMID: 28720792 PMCID: PMC5516017 DOI: 10.1038/s41598-017-03541-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 04/28/2017] [Indexed: 12/11/2022] Open
Abstract
Current neural interface technologies have serious limitations for advanced prosthetic and therapeutic applications due primarily to their lack of specificity in neural communication. An optogenetic approach has the potential to provide single cell/axon resolution in a minimally invasive manner by optical interrogation of light-sensitive reporters and actuators. Given the aim of reading neural activity in the peripheral nervous system, this work has investigated an activity-dependent signaling mechanism in the peripheral nerve. We demonstrate action potential evoked calcium signals in mammalian tibial nerve axons using an in vitro mouse model with a dextran-conjugated fluorescent calcium indicator. Spatial and temporal dynamics of the signal are presented, including characterization of frequency-modulated amplitude. Pharmacological experiments implicate T-type CaV channels and sodium-calcium exchanger (NCX) as predominant mechanisms of calcium influx. This work shows the potential of using calcium-associated optical signals for neural activity read-out in peripheral nerve axons.
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Affiliation(s)
- Arjun K Fontaine
- Department of Bioengineering, University of Colorado - Anschutz Medical Campus, Colorado, USA.
| | - Emily A Gibson
- Department of Bioengineering, University of Colorado - Anschutz Medical Campus, Colorado, USA
| | - John H Caldwell
- Department of Cell and Developmental Biology, University of Colorado - Anschutz Medical Campus, Colorado, USA
| | - Richard F Weir
- Department of Bioengineering, University of Colorado - Anschutz Medical Campus, Colorado, USA
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38
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Ikeno T, Nagano T, Hanaoka K. Silicon-substituted Xanthene Dyes and Their Unique Photophysical Properties for Fluorescent Probes. Chem Asian J 2017; 12:1435-1446. [DOI: 10.1002/asia.201700385] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 04/26/2017] [Indexed: 01/16/2023]
Affiliation(s)
- Takayuki Ikeno
- Graduate School of Pharmaceutical Sciences; The University of Tokyo; 7-3-1, Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Tetsuo Nagano
- Drug Discovery Initiative; The University of Tokyo; 7-3-1, Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Kenjiro Hanaoka
- Graduate School of Pharmaceutical Sciences; The University of Tokyo; 7-3-1, Hongo, Bunkyo-ku Tokyo 113-0033 Japan
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39
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Zhang H, Yin C, Liu T, Zhang Y, Huo F. "Turn-on" fluorescent probe detection of Ca 2+ ions and applications to bioimaging. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 180:211-216. [PMID: 28301823 DOI: 10.1016/j.saa.2017.03.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 02/24/2017] [Accepted: 03/05/2017] [Indexed: 06/06/2023]
Abstract
Ca2+ is intracellular divalent cation with the largest concentration variations and involved in many biological phenomena and often acted as a second messenger in signaling pathway. Therefore, the development of probes for specific Ca2+ detection is of great importance. Herein, a novel turn-on fluorescent probe for the detection of Ca2+ in MeCN-aqueous medium was designed and synthesized. The probe displayed responses to Ca2+ with a fluorescence enhancement at 525nm, accompanying with a distinct fluorescence change from nearly colorless to bright yellow-green. Besides, the probe exhibited a rapid signal response time (within 25s), a good linearity range and a lower detection limit (2.70×10-7M). In addition, the ability of the probe to detect Ca2+ in living cells (HeLa cells) via an enhancement of the fluorescence has also been demonstrated.
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Affiliation(s)
- Huifang Zhang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Caixia Yin
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.
| | - Tao Liu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Yongbin Zhang
- Research Institute of Applied Chemistry, Shanxi University, Taiyuan 030006, China
| | - Fangjun Huo
- Research Institute of Applied Chemistry, Shanxi University, Taiyuan 030006, China.
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40
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Tischbirek CH, Birkner A, Konnerth A. In vivo deep two-photon imaging of neural circuits with the fluorescent Ca 2+ indicator Cal-590. J Physiol 2017; 595:3097-3105. [PMID: 27995645 PMCID: PMC5430210 DOI: 10.1113/jp272790] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/15/2016] [Indexed: 01/28/2023] Open
Abstract
In vivo two-photon Ca2+ imaging has become an effective approach for the functional analysis of neuronal populations, individual neurons and subcellular neuronal compartments in the intact brain. When imaging individually labelled neurons, depth penetration can often reach up to 1 mm below the cortical surface. However, for densely labelled neuronal populations, imaging with single-cell resolution is largely restricted to the upper cortical layers in the mouse brain. Here, we review recent advances of deep two-photon Ca2+ imaging and the use of red-shifted fluorescent Ca2+ indicators as a promising strategy to increase the imaging depth, which takes advantage of reduced photon scattering at their long excitation and emission wavelengths. We describe results showing that the newly introduced fluorescent Ca2+ -sensitive dye Cal-590 can be used to record in vivo neuronal activity in isolated cortical neurons and in neurons within populations in depths of up to 900 μm below the pial surface. Thus, the new approach allows the comprehensive functional mapping of all six cortical layers of the mouse brain. Specific features of Cal-590-based in vivo Ca2+ two-photon imaging include a good signal-to-noise ratio, fast kinetics and a linear dependence of the Ca2+ transients on the number of action potentials. Another area of application is dual-colour imaging by combining Cal-590 with other, shorter wavelength Ca2+ indicators such as OGB-1. Overall, Cal-590-based two-photon microscopy emerges as a promising tool for the recording of neuronal activity at depths that were previously inaccessible to functional imaging of neuronal circuits.
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Affiliation(s)
- Carsten H. Tischbirek
- Institute of NeuroscienceTechnical University of MunichMunichGermany
- Munich Cluster for Systems Neurology (SyNergy) and Center for Integrated Protein Sciences (CIPSM)MunichGermany
| | - Antje Birkner
- Institute of NeuroscienceTechnical University of MunichMunichGermany
- Munich Cluster for Systems Neurology (SyNergy) and Center for Integrated Protein Sciences (CIPSM)MunichGermany
| | - Arthur Konnerth
- Institute of NeuroscienceTechnical University of MunichMunichGermany
- Munich Cluster for Systems Neurology (SyNergy) and Center for Integrated Protein Sciences (CIPSM)MunichGermany
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41
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Micu I, Brideau C, Lu L, Stys PK. Effects of laser polarization on responses of the fluorescent Ca 2+ indicator X-Rhod-1 in neurons and myelin. NEUROPHOTONICS 2017; 4:025002. [PMID: 28612034 PMCID: PMC5459219 DOI: 10.1117/1.nph.4.2.025002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/15/2017] [Indexed: 05/05/2023]
Abstract
Laser-scanning optical microscopes generally do not control the polarization of the exciting laser field. We show that laser polarization and imaging mode (confocal versus two photon) exert a profound influence on the ability to detect [Formula: see text] changes in both cultured neurons and living myelin. With two-photon excitation, increasing ellipticity resulted in a [Formula: see text] reduction in resting X-Rhod-1 fluorescence in homogeneous bulk solution, cell cytoplasm, and myelin. In contrast, varying the angle of a linearly polarized laser field only had appreciable effects on dyes that partitioned into myelin in an ordered manner. During injury-induced [Formula: see text] increases, larger ellipticities resulted in a significantly greater injury-induced signal increase in neurons, and particularly in myelin. Indeed, the traditional method of measuring [Formula: see text] changes using one-photon confocal mode with linearly polarized continuous wave laser illumination produced no appreciable X-Rhod-1 signal increase in ischemic myelin, compared to a robust [Formula: see text] fluorescence increase with two-photon excitation and optimized ellipticity with the identical injury paradigm. This underscores the differences in one- versus two-photon excitation and, in particular, the under-appreciated effects of laser polarization on the behavior of certain [Formula: see text] reporters, which may lead to substantial underestimates of the real [Formula: see text] fluctuations in various cellular compartments.
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Affiliation(s)
- Ileana Micu
- University of Calgary, Cumming School of Medicine, Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Craig Brideau
- University of Calgary, Cumming School of Medicine, Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Li Lu
- University of Calgary, Cumming School of Medicine, Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Peter K. Stys
- University of Calgary, Cumming School of Medicine, Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, Alberta, Canada
- Address all correspondence to: Peter K. Stys, E-mail:
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42
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Bassett JJ, Monteith GR. Genetically Encoded Calcium Indicators as Probes to Assess the Role of Calcium Channels in Disease and for High-Throughput Drug Discovery. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 79:141-171. [PMID: 28528667 DOI: 10.1016/bs.apha.2017.01.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The calcium ion (Ca2+) is an important signaling molecule implicated in many cellular processes, and the remodeling of Ca2+ homeostasis is a feature of a variety of pathologies. Typical methods to assess Ca2+ signaling in cells often employ small molecule fluorescent dyes, which are sometimes poorly suited to certain applications such as assessment of cellular processes, which occur over long periods (hours or days) or in vivo experiments. Genetically encoded calcium indicators are a set of tools available for the measurement of Ca2+ changes in the cytosol and subcellular compartments, which circumvent some of the inherent limitations of small molecule Ca2+ probes. Recent advances in genetically encoded calcium sensors have greatly increased their ability to provide reliable monitoring of Ca2+ changes in mammalian cells. New genetically encoded calcium indicators have diverse options in terms of targeting, Ca2+ affinity and fluorescence spectra, and this will further enhance their potential use in high-throughput drug discovery and other assays. This review will outline the methods available for Ca2+ measurement in cells, with a focus on genetically encoded calcium sensors. How these sensors will improve our understanding of the deregulation of Ca2+ handling in disease and their application to high-throughput identification of drug leads will also be discussed.
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Affiliation(s)
- John J Bassett
- School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia
| | - Gregory R Monteith
- School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia; Mater Research, The University of Queensland, Brisbane, QLD, Australia.
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43
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Girven KS, Sparta DR. Probing Deep Brain Circuitry: New Advances in in Vivo Calcium Measurement Strategies. ACS Chem Neurosci 2017; 8:243-251. [PMID: 27984692 DOI: 10.1021/acschemneuro.6b00307] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The study of neuronal ensembles in awake and behaving animals is a critical question in contemporary neuroscience research. Through the examination of calcium fluctuations, which are correlated with neuronal activity, we are able to better understand complex neural circuits. Recently, the development of technologies including two-photon microscopy, miniature microscopes, and fiber photometry has allowed us to examine calcium activity in behaving subjects over time. Visualizing changes in intracellular calcium in vivo has been accomplished utilizing GCaMP, a genetically encoded calcium indicator. GCaMP allows researchers to tag cell-type specific neurons with engineered fluorescent proteins that alter their levels of fluorescence in response to changes in intracellular calcium concentration. Even with the evolution of GCaMP, in vivo calcium imaging had yet to overcome the limitation of light scattering, which occurs when imaging from neural tissue in deep brain regions. Currently, researchers have created in vivo methods to bypass this problem; this Review will delve into three of these state of the art techniques: (1) two-photon calcium imaging, (2) single photon calcium imaging, and (3) fiber photometry. Here we discuss the advantages and disadvantages of the three techniques. Continued advances in these imaging techniques will provide researchers with unparalleled access to the inner workings of the brain.
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Affiliation(s)
- Kasey S. Girven
- Department
of Anatomy and Neurobiology and ‡Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Dennis R. Sparta
- Department
of Anatomy and Neurobiology and ‡Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
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44
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Abstract
Neuronal N-methyl-D-aspartate (NMDA) receptors are well known for their pivotal role in memory formation. Originally, they were thought to be exclusive to neurons. However, numerous studies revealed their functional expression also on various types of glial cells in the nervous system. Here, the methodology how to study the physiology of NMDA receptors selectively on astrocytes will be described in detail. Astrocytes are the main class of neuroglia that control transmitter and ion homeostasis, which link cerebral blood flow and neuronal energy demands, but also affect synaptic transmission directly.
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Affiliation(s)
- Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Building 48, D-66421, Homburg, Germany.
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45
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Schultz SR, Copeland CS, Foust AJ, Quicke P, Schuck R. Advances in two photon scanning and scanless microscopy technologies for functional neural circuit imaging. PROCEEDINGS OF THE IEEE. INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS 2017; 105:139-157. [PMID: 28757657 PMCID: PMC5526632 DOI: 10.1109/jproc.2016.2577380] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Recent years have seen substantial developments in technology for imaging neural circuits, raising the prospect of large scale imaging studies of neural populations involved in information processing, with the potential to lead to step changes in our understanding of brain function and dysfunction. In this article we will review some key recent advances: improved fluorophores for single cell resolution functional neuroimaging using a two photon microscope; improved approaches to the problem of scanning active circuits; and the prospect of scanless microscopes which overcome some of the bandwidth limitations of current imaging techniques. These advances in technology for experimental neuroscience have in themselves led to technical challenges, such as the need for the development of novel signal processing and data analysis tools in order to make the most of the new experimental tools. We review recent work in some active topics, such as region of interest segmentation algorithms capable of demixing overlapping signals, and new highly accurate algorithms for calcium transient detection. These advances motivate the development of new data analysis tools capable of dealing with spatial or spatiotemporal patterns of neural activity, that scale well with pattern size.
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Affiliation(s)
- Simon R Schultz
- Center for Neurotechnology and Department of Bioengineering Imperial College London, South Kensington, LondonSW7 2AZ, UK
| | - Caroline S Copeland
- Center for Neurotechnology and Department of Bioengineering Imperial College London, South Kensington, LondonSW7 2AZ, UK
| | - Amanda J Foust
- Center for Neurotechnology and Department of Bioengineering Imperial College London, South Kensington, LondonSW7 2AZ, UK
| | - Peter Quicke
- Center for Neurotechnology and Department of Bioengineering Imperial College London, South Kensington, LondonSW7 2AZ, UK
| | - Renaud Schuck
- Center for Neurotechnology and Department of Bioengineering Imperial College London, South Kensington, LondonSW7 2AZ, UK
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46
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Tăbăcaru A, Furdui B, Ghinea IO, Cârâc G, Dinică RM. Recent advances in click chemistry reactions mediated by transition metal based systems. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2016.07.029] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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47
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Collot M, Ponsot F, Klymchenko AS. Ca-NIR: a ratiometric near-infrared calcium probe based on a dihydroxanthene-hemicyanine fluorophore. Chem Commun (Camb) 2017; 53:6117-6120. [DOI: 10.1039/c7cc02418e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Ca-NIR is the first ratiometric fluorescent calcium probe emitting in the near infrared.
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Affiliation(s)
- Mayeul Collot
- Laboratoire de Biophotonique et Pharmacologie
- UMR 7213 CNRS
- Université de Strasbourg
- Faculté de Pharmacie
- 67401 ILLKIRCH Cedex
| | - Flavien Ponsot
- Laboratoire de Biophotonique et Pharmacologie
- UMR 7213 CNRS
- Université de Strasbourg
- Faculté de Pharmacie
- 67401 ILLKIRCH Cedex
| | - Andrey S. Klymchenko
- Laboratoire de Biophotonique et Pharmacologie
- UMR 7213 CNRS
- Université de Strasbourg
- Faculté de Pharmacie
- 67401 ILLKIRCH Cedex
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48
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Pendin D, Greotti E, Lefkimmiatis K, Pozzan T. Exploring cells with targeted biosensors. J Gen Physiol 2016; 149:1-36. [PMID: 28028123 PMCID: PMC5217087 DOI: 10.1085/jgp.201611654] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/26/2016] [Accepted: 12/01/2016] [Indexed: 01/10/2023] Open
Abstract
Cellular signaling networks are composed of multiple pathways, often interconnected, that form complex networks with great potential for cross-talk. Signal decoding depends on the nature of the message as well as its amplitude, temporal pattern, and spatial distribution. In addition, the existence of membrane-bound organelles, which are both targets and generators of messages, add further complexity to the system. The availability of sensors that can localize to specific compartments in live cells and monitor their targets with high spatial and temporal resolution is thus crucial for a better understanding of cell pathophysiology. For this reason, over the last four decades, a variety of strategies have been developed, not only to generate novel and more sensitive probes for ions, metabolites, and enzymatic activity, but also to selectively deliver these sensors to specific intracellular compartments. In this review, we summarize the principles that have been used to target organic or protein sensors to different cellular compartments and their application to cellular signaling.
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Affiliation(s)
- Diana Pendin
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Elisa Greotti
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Konstantinos Lefkimmiatis
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Tullio Pozzan
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Venetian Institute of Molecular Medicine, 35129 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
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49
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Birkner A, Tischbirek CH, Konnerth A. Improved deep two-photon calcium imaging in vivo. Cell Calcium 2016; 64:29-35. [PMID: 28027798 DOI: 10.1016/j.ceca.2016.12.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 12/19/2016] [Indexed: 01/26/2023]
Abstract
Two-photon laser scanning calcium imaging has emerged as a useful method for the exploration of neural function and structure at the cellular and subcellular level in vivo. The applications range from imaging of subcellular compartments such as dendrites, spines and axonal boutons up to the functional analysis of large neuronal or glial populations. However, the depth penetration is often limited to a few hundred micrometers, corresponding, for example, to the upper cortical layers of the mouse brain. Light scattering and aberrations originating from refractive index inhomogeneties of the tissue are the reasons for these limitations. The depth penetration of two-photon imaging can be enhanced through various approaches, such as the implementation of adaptive optics, the use of three-photon excitation and/or labeling cells with red-shifted genetically encoded fluorescent sensors. However, most of the approaches used so far require the implementation of new instrumentation and/or time consuming staining protocols. Here we present a simple approach that can be readily implemented in combination with standard two-photon microscopes. The method involves an optimized protocol for depth-restricted labeling with the red-shifted fluorescent calcium indicator Cal-590 and benefits from the use of ultra-short laser pulses. The approach allows in vivo functional imaging of neuronal populations with single cell resolution in all six layers of the mouse cortex. We demonstrate that stable recordings in deep cortical layers are not restricted to anesthetized animals but are well feasible in awake, behaving mice. We anticipate that the improved depth penetration will be beneficial for two-photon functional imaging in larger species, such as non-human primates.
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Affiliation(s)
- Antje Birkner
- Institute of Neuroscience, Technical University of Munich, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy) and Center for Integrated Protein Sciences (CIPSM), Munich, Germany.
| | - Carsten H Tischbirek
- Institute of Neuroscience, Technical University of Munich, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy) and Center for Integrated Protein Sciences (CIPSM), Munich, Germany
| | - Arthur Konnerth
- Institute of Neuroscience, Technical University of Munich, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy) and Center for Integrated Protein Sciences (CIPSM), Munich, Germany.
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50
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Deán-Ben XL, Sela G, Lauri A, Kneipp M, Ntziachristos V, Westmeyer GG, Shoham S, Razansky D. Functional optoacoustic neuro-tomography for scalable whole-brain monitoring of calcium indicators. LIGHT, SCIENCE & APPLICATIONS 2016; 5:e16201. [PMID: 30167137 PMCID: PMC6059886 DOI: 10.1038/lsa.2016.201] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 08/09/2016] [Accepted: 08/11/2016] [Indexed: 05/07/2023]
Abstract
Non-invasive observation of spatiotemporal activity of large neural populations distributed over entire brains is a longstanding goal of neuroscience. We developed a volumetric multispectral optoacoustic tomography platform for imaging neural activation deep in scattering brains. It can record 100 volumetric frames per second across scalable fields of view ranging between 50 and 1000 mm3 with respective spatial resolution of 35-200 μm. Experiments performed in immobilized and freely swimming larvae and in adult zebrafish brains expressing the genetically encoded calcium indicator GCaMP5G demonstrate, for the first time, the fundamental ability to directly track neural dynamics using optoacoustics while overcoming the longstanding penetration barrier of optical imaging in scattering brains. The newly developed platform thus offers unprecedented capabilities for functional whole-brain observations of fast calcium dynamics; in combination with optoacoustics' well-established capacity for resolving vascular hemodynamics, it could open new vistas in the study of neural activity and neurovascular coupling in health and disease.
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Affiliation(s)
- X Luís Deán-Ben
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany
| | - Gali Sela
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany
| | - Antonella Lauri
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany
- Institute of Developmental Genetics, Helmholtz Center Munich, Neuherberg, Germany
| | - Moritz Kneipp
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany
- Department of Medicine, Technical University of Munich, Munich, Germany
| | - Vasilis Ntziachristos
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany
- Department of Medicine, Technical University of Munich, Munich, Germany
| | - Gil G Westmeyer
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany
- Institute of Developmental Genetics, Helmholtz Center Munich, Neuherberg, Germany
- Department of Medicine, Technical University of Munich, Munich, Germany
| | - Shy Shoham
- Department of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Daniel Razansky
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany
- Department of Medicine, Technical University of Munich, Munich, Germany
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