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Liu S, Lin C, Xu Y, Luo H, Peng L, Zeng X, Zheng H, Chen PR, Zou P. A far-red hybrid voltage indicator enabled by bioorthogonal engineering of rhodopsin on live neurons. Nat Chem 2021; 13:472-479. [PMID: 33859392 DOI: 10.1038/s41557-021-00641-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 01/15/2021] [Indexed: 01/24/2023]
Abstract
Membrane potential is a key aspect of cellular signalling and is dynamically regulated by an array of ion-selective pumps and channels. Fluorescent voltage indicators enable non-invasive optical recording of the cellular membrane potential with high spatial resolution. Here, we report a palette of bright and sensitive hybrid voltage indicators (HVIs) with fluorescence intensities sensitive to changes in membrane potential via electrochromic Förster resonance energy transfer. Enzyme-mediated site-specific incorporation of a probe, followed by an inverse-electron-demand Diels-Alder cycloaddition, was used to create enhanced voltage-sensing rhodopsins with hybrid dye-protein architectures. The most sensitive indicator, HVI-Cy3, displays high voltage sensitivity (-39% ΔF/F0 per 100 mV) and millisecond response kinetics, enabling optical recording of action potentials at a sampling rate of 400 Hz over 10 min across a large neuronal population. The far-red indicator HVI-Cy5 could be paired with optogenetic actuators and green/red-emitting fluorescent indicators, allowing an all-optical investigation of neuronal electrophysiology.
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Affiliation(s)
- Shuzhang Liu
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China
| | - Chang Lin
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China
| | - Yongxian Xu
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China.,School of Life Sciences, Tsinghua University, Beijing, China
| | - Huixin Luo
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China
| | - Luxin Peng
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China
| | - Xiangmei Zeng
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China
| | - Huangtao Zheng
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China
| | - Peng R Chen
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China. .,Peking-Tsinghua Center for Life Sciences, Beijing, China.
| | - Peng Zou
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, Peking University, Beijing, China. .,Peking-Tsinghua Center for Life Sciences, Beijing, China. .,PKU-IDG/McGovern Institute for Brain Research, Beijing, China. .,Chinese Institute for Brain Research (CIBR), Beijing, China.
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52
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Cai C, Friedrich J, Singh A, Eybposh MH, Pnevmatikakis EA, Podgorski K, Giovannucci A. VolPy: Automated and scalable analysis pipelines for voltage imaging datasets. PLoS Comput Biol 2021; 17:e1008806. [PMID: 33852574 PMCID: PMC8075204 DOI: 10.1371/journal.pcbi.1008806] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 04/26/2021] [Accepted: 02/16/2021] [Indexed: 12/19/2022] Open
Abstract
Voltage imaging enables monitoring neural activity at sub-millisecond and sub-cellular scale, unlocking the study of subthreshold activity, synchrony, and network dynamics with unprecedented spatio-temporal resolution. However, high data rates (>800MB/s) and low signal-to-noise ratios create bottlenecks for analyzing such datasets. Here we present VolPy, an automated and scalable pipeline to pre-process voltage imaging datasets. VolPy features motion correction, memory mapping, automated segmentation, denoising and spike extraction, all built on a highly parallelizable, modular, and extensible framework optimized for memory and speed. To aid automated segmentation, we introduce a corpus of 24 manually annotated datasets from different preparations, brain areas and voltage indicators. We benchmark VolPy against ground truth segmentation, simulations and electrophysiology recordings, and we compare its performance with existing algorithms in detecting spikes. Our results indicate that VolPy's performance in spike extraction and scalability are state-of-the-art.
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Affiliation(s)
- Changjia Cai
- Joint Department of Biomedical Engineering at University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States of America
| | - Johannes Friedrich
- Flatiron Institute, Simons Foundation, New York, New York, United States of America
| | - Amrita Singh
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - M. Hossein Eybposh
- Joint Department of Biomedical Engineering at University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States of America
| | | | - Kaspar Podgorski
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Andrea Giovannucci
- Joint Department of Biomedical Engineering at University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States of America
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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53
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Leong LM, Kang BE, Baker BJ. Improving the flexibility of genetically encoded voltage indicators via intermolecular FRET. Biophys J 2021; 120:1927-1941. [PMID: 33744262 PMCID: PMC8204331 DOI: 10.1016/j.bpj.2021.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 02/25/2021] [Accepted: 03/10/2021] [Indexed: 11/16/2022] Open
Abstract
A new family of genetically encoded voltage indicators (GEVIs) has been developed based on intermolecular Förster resonance energy transfer (FRET). To test the hypothesis that the GEVI ArcLight functions via interactions between the fluorescent protein (FP) domains of neighboring probes, the FP of ArcLight was replaced with either a FRET donor or acceptor FP. We discovered relatively large FRET signals only when cells were cotransfected with both the FRET donor and acceptor GEVIs. Using a cyan fluorescent protein donor and an RFP acceptor, we were able to observe a voltage-dependent signal with an emission peak separated by over 200 nm from the excitation wavelength. The intermolecular FRET strategy also works for rhodopsin-based probes, potentially improving their flexibility as well. Separating the FRET pair into two distinct proteins has important advantages over intramolecular FRET constructs. The signals are larger because the voltage-induced conformational change moves two FPs independently. The expression of the FRET donor and acceptor can also be restricted independently, enabling greater cell type specificity as well as refined subcellular voltage reporting.
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Affiliation(s)
- Lee Min Leong
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul, Republic of Korea; Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea
| | - Bok Eum Kang
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul, Republic of Korea
| | - Bradley J Baker
- Brain Science Institute, Korea Institute of Science and Technology, Seongbuk-gu, Seoul, Republic of Korea; Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea.
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54
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Adam Y. All-optical electrophysiology in behaving animals. J Neurosci Methods 2021; 353:109101. [PMID: 33600851 DOI: 10.1016/j.jneumeth.2021.109101] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/13/2021] [Accepted: 02/09/2021] [Indexed: 12/28/2022]
Abstract
Technology for simultaneous control and readout of the membrane potential of multiple neurons in behaving animals at high spatio-temporal resolution will have a high impact on neuroscience research. Significant progress in the development of Genetically Encoded Voltage Indicators (GEVIs) now enables to optically record subthreshold and spiking activity from ensembles of cells in behaving animals. In some cases, the GEVIs were also combined with optogenetic actuators to enable 'all-optical' control and readout of membrane potential at cellular resolution. Here I describe the recent progress in GEVI development and discuss the various aspects necessary to perform a successful 'all-optical' electrophysiology experiment in behaving, head-fixed animals. These aspects include the voltage indicators, the optogenetic actuators, strategies for protein expression, optical hardware, and image processing software. Furthermore, I discuss various applications of the technology, highlighting its advantages over classic electrode-based techniques. I argue that GEVIs now transformed from a 'promising' technology to a practical tool that can be used to tackle fundamental questions in neuroscience.
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Affiliation(s)
- Yoav Adam
- Edmond and Lily Safra Center for Brain Science, The Hebrew University of Jerusalem, Jerusalem, Israel.
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55
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Gonzalez MA, Walker AS, Cao KJ, Lazzari-Dean JR, Settineri NS, Kong EJ, Kramer RH, Miller EW. Voltage Imaging with a NIR-Absorbing Phosphine Oxide Rhodamine Voltage Reporter. J Am Chem Soc 2021; 143:2304-2314. [PMID: 33501825 PMCID: PMC7986050 DOI: 10.1021/jacs.0c11382] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The development of fluorescent dyes that emit and absorb light at wavelengths greater than 700 nm and that respond to biochemical and biophysical events in living systems remains an outstanding challenge for noninvasive optical imaging. Here, we report the design, synthesis, and application of near-infrared (NIR)-absorbing and -emitting optical voltmeter based on a sulfonated, phosphine-oxide (po) rhodamine for voltage imaging in intact retinas. We find that po-rhodamine based voltage reporters, or poRhoVRs, display NIR excitation and emission profiles at greater than 700 nm, show a range of voltage sensitivities (13 to 43% ΔF/F per 100 mV in HEK cells), and can be combined with existing optical sensors, like Ca2+-sensitive fluorescent proteins (GCaMP), and actuators, like light-activated opsins ChannelRhodopsin-2 (ChR2). Simultaneous voltage and Ca2+ imaging reveals differences in activity dynamics in rat hippocampal neurons, and pairing poRhoVR with blue-light based ChR2 affords all-optical electrophysiology. In ex vivo retinas isolated from a mouse model of retinal degeneration, poRhoVR, together with GCaMP-based Ca2+ imaging and traditional multielectrode array (MEA) recording, can provide a comprehensive physiological activity profile of neuronal activity, revealing differences in voltage and Ca2+ dynamics within hyperactive networks of the mouse retina. Taken together, these experiments establish that poRhoVR will open new horizons in optical interrogation of cellular and neuronal physiology in intact systems.
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Affiliation(s)
- Monica A. Gonzalez
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Alison S. Walker
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
| | - Kevin J. Cao
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
| | - Julia R. Lazzari-Dean
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Nicholas S. Settineri
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Eui Ju Kong
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Richard H. Kramer
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
- Department of Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
| | - Evan W. Miller
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
- Department of Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
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56
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Mollinedo-Gajate I, Song C, Knöpfel T. Genetically Encoded Voltage Indicators. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1293:209-224. [PMID: 33398815 DOI: 10.1007/978-981-15-8763-4_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Optogenetic approaches combine the power to allocate optogenetic tools (proteins) to specific cell populations (defined genetically or functionally) and the use of light-based interfaces between biological wetware (cells and tissues) and hardware (controllers and recorders). The optogenetic toolbox contains two main compartments: tools to interfere with cellular processes and tools to monitor cellular events. Among the latter are genetically encoded voltage indicators (GEVIs). This chapter outlines the development, current state of the art and prospects of emerging optical GEVI imaging technologies.
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Affiliation(s)
| | - Chenchen Song
- Laboratory for Neuronal Circuit Dynamics, Imperial College London, London, UK
| | - Thomas Knöpfel
- Laboratory for Neuronal Circuit Dynamics, Imperial College London, London, UK.
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57
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Identification and quantification of neuronal ensembles in optical imaging experiments. J Neurosci Methods 2020; 351:109046. [PMID: 33359231 DOI: 10.1016/j.jneumeth.2020.109046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/12/2020] [Accepted: 12/15/2020] [Indexed: 12/30/2022]
Abstract
Recent technical advances in molecular biology and optical imaging have made it possible to record from up to thousands of densely packed neurons in superficial and deep brain regions in vivo, with cellular subtype specificity and high spatiotemporal fidelity. Such optical neurotechnologies are enabling increasingly fine-scaled studies of neuronal circuits and reliably co-active groups of neurons, so-called ensembles. Neuronal ensembles are thought to constitute the basic functional building blocks of brain systems, potentially exhibiting collective computational properties. While the technical framework of in vivo optical imaging and quantification of neuronal activity follows certain widely held standards, analytical methods for study of neuronal co-activity and ensembles lack consensus and are highly varied across the field. Here we provide a comprehensive step-by-step overview of theoretical, experimental, and analytical considerations for the identification and quantification of neuronal ensemble dynamics in high-resolution in vivo optical imaging studies.
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58
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Monakhov MV, Matlashov ME, Colavita M, Song C, Shcherbakova DM, Antic SD, Verkhusha VV, Knöpfel T. Screening and Cellular Characterization of Genetically Encoded Voltage Indicators Based on Near-Infrared Fluorescent Proteins. ACS Chem Neurosci 2020; 11:3523-3531. [PMID: 33063984 DOI: 10.1021/acschemneuro.0c00046] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We developed genetically encoded voltage indicators using a transmembrane voltage-sensing domain and bright near-infrared fluorescent proteins derived from bacterial phytochromes. These new voltage indicators are excited by 640 nm light and emission is measured at 670 nm, allowing imaging in the near-infrared tissue transparency window. The spectral properties of our new indicators permit seamless voltage imaging with simultaneous blue-green light optogenetic actuator activation as well as simultaneous voltage-calcium imaging when paired with green calcium indicators. Iterative optimizations led to a fluorescent probe, here termed nirButterfly, which reliably reports neuronal activities including subthreshold membrane potential depolarization and hyperpolarization as well as spontaneous spiking or electrically- and optogenetically evoked action potentials. This enables largely improved all-optical causal interrogations of physiology.
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Affiliation(s)
- Mikhail V Monakhov
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, Connecticut 06030, United States
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Mikhail E Matlashov
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Michelangelo Colavita
- Laboratory for Neuronal Circuit Dynamics, Imperial College London, London W12 0NN, U.K
| | - Chenchen Song
- Laboratory for Neuronal Circuit Dynamics, Imperial College London, London W12 0NN, U.K
| | - Daria M Shcherbakova
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Srdjan D Antic
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, Connecticut 06030, United States
| | - Vladislav V Verkhusha
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Thomas Knöpfel
- Laboratory for Neuronal Circuit Dynamics, Imperial College London, London W12 0NN, U.K
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59
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Zhou X, Mehta S, Zhang J. Genetically Encodable Fluorescent and Bioluminescent Biosensors Light Up Signaling Networks. Trends Biochem Sci 2020; 45:889-905. [PMID: 32660810 PMCID: PMC7502535 DOI: 10.1016/j.tibs.2020.06.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 05/25/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022]
Abstract
Cell signaling networks are intricately regulated in time and space to determine the responses and fates of cells to different cues. Genetically encodable fluorescent and bioluminescent biosensors enable the direct visualization of these spatiotemporal signaling dynamics within the native biological context, and have therefore become powerful molecular tools whose unique benefits are being used to address challenging biological questions. We first review the basis of biosensor design and remark on recent technologies that are accelerating biosensor development. We then discuss a few of the latest advances in the development and application of genetically encodable fluorescent and bioluminescent biosensors that have led to scientific or technological breakthroughs.
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Affiliation(s)
- Xin Zhou
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA.
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60
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Milosevic MM, Jang J, McKimm EJ, Zhu MH, Antic SD. In Vitro Testing of Voltage Indicators: Archon1, ArcLightD, ASAP1, ASAP2s, ASAP3b, Bongwoori-Pos6, BeRST1, FlicR1, and Chi-VSFP-Butterfly. eNeuro 2020; 7:ENEURO.0060-20.2020. [PMID: 32817120 PMCID: PMC7540930 DOI: 10.1523/eneuro.0060-20.2020] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 08/03/2020] [Accepted: 08/09/2020] [Indexed: 01/04/2023] Open
Abstract
Genetically encoded voltage indicators (GEVIs) could potentially be used for mapping neural circuits at the plane of synaptic potentials and plateau potentials-two blind spots of GCaMP-based imaging. In the last year alone, several laboratories reported significant breakthroughs in the quality of GEVIs and the efficacy of the voltage imaging equipment. One major obstacle of using well performing GEVIs in the pursuit of interesting biological data is the process of transferring GEVIs between laboratories, as their reported qualities (e.g., membrane targeting, brightness, sensitivity, optical signal quality) are often difficult to reproduce outside of the laboratory of the GEVI origin. We have tested eight available GEVIs (Archon1, ArcLightD, ASAP1, ASAP2s, ASAP3b, Bongwoori-Pos6, FlicR1, and chi-VSFP-Butterfly) and two voltage-sensitive dyes (BeRST1 and di-4-ANEPPS). We used the same microscope, lens, and optical detector, while the light sources were interchanged. GEVI voltage imaging was attempted in the following three preparations: (1) cultured neurons, (2) HEK293 cells, and (3) mouse brain slices. Systematic measurements were successful only in HEK293 cells and brain slices. Despite the significant differences in brightness and dynamic response (ON rate), all tested indicators produced reasonable optical signals in brain slices and solid in vitro quality properties, in the range initially reported by the creator laboratories. Side-by-side comparisons between GEVIs and organic dyes obtained in HEK293 cells and brain slices by a "third party" (current data) will be useful for determining the right voltage indicator for a given research application.
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Affiliation(s)
- Milena M Milosevic
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
- Center for Laser Microscopy, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Jinyoung Jang
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
| | - Eric J McKimm
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
| | - Mei Hong Zhu
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
| | - Srdjan D Antic
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
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61
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Penzkofer A, Silapetere A, Hegemann P. Absorption and Emission Spectroscopic Investigation of the Thermal Dynamics of the Archaerhodopsin 3 Based Fluorescent Voltage Sensor Archon2. Int J Mol Sci 2020; 21:ijms21186576. [PMID: 32911811 PMCID: PMC7555599 DOI: 10.3390/ijms21186576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/28/2020] [Accepted: 09/01/2020] [Indexed: 01/12/2023] Open
Abstract
Archon2 is a fluorescent voltage sensor derived from Archaerhodopsin 3 (Arch) of Halorubrum sodomense using robotic multidimensional directed evolution approach. Here we report absorption and emission spectroscopic studies of Archon2 in Tris buffer at pH 8. Absorption cross-section spectra, fluorescence quantum distributions, fluorescence quantum yields, and fluorescence excitation spectra were determined. The thermal stability of Archon2 was studied by long-time attenuation coefficient measurements at room temperature (21 ± 1 °C) and at refrigerator temperature (3 ± 1 °C). The apparent melting temperature was determined by stepwise sample heating up and cooling down (obtained apparent melting temperature: 63 ± 3 °C). In the protein melting process protonated retinal Schiff base (PRSB) with absorption maximum at 586 nm converted to de-protonated retinal Schiff base (RSB) with absorption maximum at 380 nm. Storage of Archon2 at room temperature and refrigerator temperature caused absorption coefficient decrease because of partial protein clustering to aggregates at condensation nuclei and sedimentation. At room temperature an onset of light scattering was observed after two days because of the beginning of protein unfolding. During the period of observation (18 days at 21 °C, 22 days at 3 °C) no change of retinal isomer composition was observed indicating a high potential energy barrier of S0 ground-state isomerization.
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Affiliation(s)
- Alfons Penzkofer
- Fakultät für Physik, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
- Correspondence: ; Tel.: +49-941-943-2107
| | - Arita Silapetere
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany; (A.S.); (P.H.)
| | - Peter Hegemann
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany; (A.S.); (P.H.)
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62
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Pal A, Tian L. Imaging voltage and brain chemistry with genetically encoded sensors and modulators. Curr Opin Chem Biol 2020; 57:166-176. [PMID: 32823064 DOI: 10.1016/j.cbpa.2020.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 01/21/2023]
Abstract
Neurons and glia are functionally organized into circuits and higher-order structures that allow the precise information processing required for complex behaviors. To better understand the structure and function of the brain, we must understand synaptic connectivity, action potential generation and propagation, as well as well-orchestrated molecular signaling. Recently, dramatically improved sensors for voltage, intracellular calcium, and neurotransmitters/modulators, combined with advanced microscopy provide new opportunities for in vivo dissection of cellular and circuit activity in awake, behaving animals. This review focuses on the current trends in genetically encoded sensors for molecules and cellular events and their potential applicability to the study of nervous system in health and disease.
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Affiliation(s)
- Akash Pal
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, USA
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, USA.
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63
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Chakrabarti S, Ai M, Henson FM, Smith ESJ. Peripheral mechanisms of arthritic pain: A proposal to leverage large animals for in vitro studies. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2020; 8:100051. [PMID: 32817908 PMCID: PMC7426561 DOI: 10.1016/j.ynpai.2020.100051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 04/14/2023]
Abstract
Pain arising from musculoskeletal disorders such as arthritis is one of the leading causes of disability. Whereas the past 20-years has seen an increase in targeted therapies for rheumatoid arthritis (RA), other arthritis conditions, especially osteoarthritis, remain poorly treated. Although modulation of central pain pathways occurs in chronic arthritis, multiple lines of evidence indicate that peripherally driven pain is important in arthritic pain. To understand the peripheral mechanisms of arthritic pain, various in vitro and in vivo models have been developed, largely in rodents. Although rodent models provide numerous advantages for studying arthritis pathogenesis and treatment, the anatomy and biomechanics of rodent joints differ considerably to those of humans. By contrast, the anatomy and biomechanics of joints in larger animals, such as dogs, show greater similarity to human joints and thus studying them can provide novel insight for arthritis research. The purpose of this article is firstly to review models of arthritis and behavioral outcomes commonly used in large animals. Secondly, we review the existing in vitro models and assays used to study arthritic pain, primarily in rodents, and discuss the potential for adopting these strategies, as well as likely limitations, in large animals. We believe that exploring peripheral mechanisms of arthritic pain in vitro in large animals has the potential to reduce the veterinary burden of arthritis in commonly afflicted species like dogs, as well as to improve translatability of pain research into the clinic.
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Affiliation(s)
- Sampurna Chakrabarti
- Department of Neuroscience, Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
- Department of Pharmacology, University of Cambridge, UK
| | - Minji Ai
- Department of Veterinary Medicine, University of Cambridge, UK
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64
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Liu Y, Lu Y, Chen G, Wang Q. Recent Progress of Hybrid Optical Probes for Neural Membrane Potential Imaging. Biotechnol J 2020; 15:e2000086. [PMID: 32662937 DOI: 10.1002/biot.202000086] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/04/2020] [Indexed: 12/17/2022]
Abstract
The neural membrane potential of nerve cells is the basis of neural activity production, which controls advanced brain activities such as memory, emotion, and learning. In the past decades, optical voltage indicator has emerged as a promising tool to decode neural activities with high-fidelity and excellent spatiotemporal resolution. In particular, the hybrid optical probes can combine the advantageous photophysical properties of different components such as voltage-sensitive molecules, highly fluorescent fluorophores, membrane-targeting tags, and optogenetic materials, thus showing numerous advantages in improving the photoluminescence intensity, voltage sensitivity, photostability, and cell specificity of probes. In this review, the current state-of-the-art hybrid probes are highlighted, that are designed by using fluorescent proteins, organic dyes, and fluorescent nanoprobes as the fluorophores, respectively. Then, the design strategies, voltage-sensing mechanisms and the in vitro and in vivo neural activity imaging applications of the hybrid probes are summarized. Finally, based on the current achievements of voltage imaging studies, the challenges and prospects for design and application of hybrid optical probes in the future are presented.
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Affiliation(s)
- Yongyang Liu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Yaxin Lu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Guangcun Chen
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Qiangbin Wang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China.,College of Materials Sciences and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
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Oltmanns S, Abben FS, Ender A, Aimon S, Kovacs R, Sigrist SJ, Storace DA, Geiger JRP, Raccuglia D. NOSA, an Analytical Toolbox for Multicellular Optical Electrophysiology. Front Neurosci 2020; 14:712. [PMID: 32765213 PMCID: PMC7381214 DOI: 10.3389/fnins.2020.00712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/12/2020] [Indexed: 11/23/2022] Open
Abstract
Understanding how neural networks generate activity patterns and communicate with each other requires monitoring the electrical activity from many neurons simultaneously. Perfectly suited tools for addressing this challenge are genetically encoded voltage indicators (GEVIs) because they can be targeted to specific cell types and optically report the electrical activity of individual, or populations of neurons. However, analyzing and interpreting the data from voltage imaging experiments is challenging because high recording speeds and properties of current GEVIs yield only low signal-to-noise ratios, making it necessary to apply specific analytical tools. Here, we present NOSA (Neuro-Optical Signal Analysis), a novel open source software designed for analyzing voltage imaging data and identifying temporal interactions between electrical activity patterns of different origin. In this work, we explain the challenges that arise during voltage imaging experiments and provide hands-on analytical solutions. We demonstrate how NOSA's baseline fitting, filtering algorithms and movement correction can compensate for shifts in baseline fluorescence and extract electrical patterns from low signal-to-noise recordings. NOSA allows to efficiently identify oscillatory frequencies in electrical patterns, quantify neuronal response parameters and moreover provides an option for analyzing simultaneously recorded optical and electrical data derived from patch-clamp or other electrode-based recordings. To identify temporal relations between electrical activity patterns we implemented different options to perform cross correlation analysis, demonstrating their utility during voltage imaging in Drosophila and mice. All features combined, NOSA will facilitate the first steps into using GEVIs and help to realize their full potential for revealing cell-type specific connectivity and functional interactions.
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Affiliation(s)
- Sebastian Oltmanns
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Frauke Sophie Abben
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Anatoli Ender
- German Center for Neurodegenerative Diseases, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Sophie Aimon
- School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Richard Kovacs
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Stephan J. Sigrist
- German Center for Neurodegenerative Diseases, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Institute of Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Douglas A. Storace
- Department of Biological Science, Florida State University, Tallahassee, FL, United States
| | - Jörg R. P. Geiger
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Davide Raccuglia
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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66
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A general approach to engineer positive-going eFRET voltage indicators. Nat Commun 2020; 11:3444. [PMID: 32651384 PMCID: PMC7351947 DOI: 10.1038/s41467-020-17322-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/18/2020] [Indexed: 01/26/2023] Open
Abstract
Imaging membrane voltage from genetically defined cells offers the unique ability to report spatial and temporal dynamics of electrical signaling at cellular and circuit levels. Here, we present a general approach to engineer electrochromic fluorescence resonance energy transfer (eFRET) genetically encoded voltage indicators (GEVIs) with positive-going fluorescence response to membrane depolarization through rational manipulation of the native proton transport pathway in microbial rhodopsins. We transform the state-of-the-art eFRET GEVI Voltron into Positron, with kinetics and sensitivity equivalent to Voltron but flipped fluorescence signal polarity. We further apply this general approach to GEVIs containing different voltage sensitive rhodopsin domains and various fluorescent dye and fluorescent protein reporters.
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67
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Rhee JK, Leong LM, Mukim MSI, Kang BE, Lee S, Bilbao-Broch L, Baker BJ. Biophysical Parameters of GEVIs: Considerations for Imaging Voltage. Biophys J 2020; 119:1-8. [PMID: 32521239 PMCID: PMC7335909 DOI: 10.1016/j.bpj.2020.05.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 04/17/2020] [Accepted: 05/20/2020] [Indexed: 11/29/2022] Open
Abstract
Genetically encoded voltage indicators (GEVIs) continue to evolve, resulting in many different probes with varying strengths and weaknesses. Developers of new GEVIs tend to highlight their positive features. A recent article from an independent laboratory has compared the signal/noise ratios of a number of GEVIs. Such a comparison can be helpful to investigators eager to try to image the voltage of excitable cells. In this perspective, we will present examples of how the biophysical features of GEVIs affect the imaging of excitable cells in an effort to assist researchers when considering probes for their specific needs.
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Affiliation(s)
- Jun Kyu Rhee
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea; Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea
| | - Lee Min Leong
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea; Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea
| | - Md Sofequl Islam Mukim
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea; Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea
| | - Bok Eum Kang
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Sungmoo Lee
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Laura Bilbao-Broch
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea; Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea
| | - Bradley J Baker
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea; Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea.
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68
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Quicke P, Howe CL, Song P, Jadan HV, Song C, Knöpfel T, Neil M, Dragotti PL, Schultz SR, Foust AJ. Subcellular resolution three-dimensional light-field imaging with genetically encoded voltage indicators. NEUROPHOTONICS 2020; 7:035006. [PMID: 32904628 PMCID: PMC7456658 DOI: 10.1117/1.nph.7.3.035006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/07/2020] [Indexed: 05/13/2023]
Abstract
Significance: Light-field microscopy (LFM) enables high signal-to-noise ratio (SNR) and light efficient volume imaging at fast frame rates. Voltage imaging with genetically encoded voltage indicators (GEVIs) stands to particularly benefit from LFM's volumetric imaging capability due to high required sampling rates and limited probe brightness and functional sensitivity. Aim: We demonstrate subcellular resolution GEVI light-field imaging in acute mouse brain slices resolving dendritic voltage signals in three spatial dimensions. Approach: We imaged action potential-induced fluorescence transients in mouse brain slices sparsely expressing the GEVI VSFP-Butterfly 1.2 in wide-field microscopy (WFM) and LFM modes. We compared functional signal SNR and localization between different LFM reconstruction approaches and between LFM and WFM. Results: LFM enabled three-dimensional (3-D) localization of action potential-induced fluorescence transients in neuronal somata and dendrites. Nonregularized deconvolution decreased SNR with increased iteration number compared to synthetic refocusing but increased axial and lateral signal localization. SNR was unaffected for LFM compared to WFM. Conclusions: LFM enables 3-D localization of fluorescence transients, therefore eliminating the need for structures to lie in a single focal plane. These results demonstrate LFM's potential for studying dendritic integration and action potential propagation in three spatial dimensions.
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Affiliation(s)
- Peter Quicke
- Imperial College London, Department of Bioengineering, London, United Kingdom
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
| | - Carmel L. Howe
- Imperial College London, Department of Bioengineering, London, United Kingdom
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
| | - Pingfan Song
- Imperial College London, Department of Electrical and Electronic Engineering, London, United Kingdom
| | - Herman V. Jadan
- Imperial College London, Department of Electrical and Electronic Engineering, London, United Kingdom
| | - Chenchen Song
- Imperial College London, Department of Brain Sciences, London, United Kingdom
| | - Thomas Knöpfel
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
- Imperial College London, Department of Brain Sciences, London, United Kingdom
| | - Mark Neil
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
- Imperial College London, Department of Physics, London, United Kingdom
| | - Pier L. Dragotti
- Imperial College London, Department of Electrical and Electronic Engineering, London, United Kingdom
| | - Simon R. Schultz
- Imperial College London, Department of Bioengineering, London, United Kingdom
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
- Address all correspondence to Simon R. Schultz, E-mail: ; Amanda J. Foust, E-mail:
| | - Amanda J. Foust
- Imperial College London, Department of Bioengineering, London, United Kingdom
- Imperial College London, Centre for Neurotechnology, London, United Kingdom
- Address all correspondence to Simon R. Schultz, E-mail: ; Amanda J. Foust, E-mail:
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69
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Kohara K, Inoue A, Nakano Y, Hirai H, Kobayashi T, Maruyama M, Baba R, Kawashima C. BATTLE: Genetically Engineered Strategies for Split-Tunable Allocation of Multiple Transgenes in the Nervous System. iScience 2020; 23:101248. [PMID: 32629613 PMCID: PMC7322263 DOI: 10.1016/j.isci.2020.101248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/02/2019] [Accepted: 06/04/2020] [Indexed: 11/26/2022] Open
Abstract
Elucidating fine architectures and functions of cellular and synaptic connections requires development of new flexible methods. Here, we created a concept called the “battle of transgenes,” based on which we generated strategies using genetically engineered battles of multiple recombinases. The strategies enabled split-tunable allocation of multiple transgenes. We demonstrated the versatility of these strategies and technologies in inducing strong and multi-sparse allocations of multiple transgenes. Furthermore, the combination of our transgenic strategy and expansion microscopy enabled three-dimensional high-resolution imaging of whole synaptic structures in the hippocampus with simultaneous visualizations of endogenous synaptic proteins. These strategies and technologies based on the battle of genes may accelerate the analysis of whole synaptic and cellular connections in diverse life science fields. Generation of BATTLE-recombinase systems for allocation of multiple transgenes Split-tunable allocation in BATTLE-1 and multi-sparse allocation in BATTLE-2 Clear and strong labeling of dendrites and axons using BATTLE-2 3D high-resolution imaging of whole synapses in hippocampus in BATTLE-1EX
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Affiliation(s)
- Keigo Kohara
- Department of Cellular and Functional Biology, Institute of Biomedical Science, Kansai Medical University, Hirakata, Osaka 573-1010, Japan.
| | - Akitoshi Inoue
- Department of Medical Chemistry, Kansai Medical University, Graduate School of Medicine, Hirakata, Osaka 573-1010, Japan
| | - Yousuke Nakano
- Department of Anatomy, Kansai Medical University, Graduate School of Medicine, Hirakata, Osaka 573-1010, Japan
| | - Hirokazu Hirai
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan; Research Program for Neural Signalling, Division of Endocrinology, Metabolism and Signal Research, Gunma University Initiative for Advanced Research, Maebashi, Gunma 371-8512, Japan
| | - Takuya Kobayashi
- Department of Medical Chemistry, Kansai Medical University, Graduate School of Medicine, Hirakata, Osaka 573-1010, Japan; Japan Agency for Medical Research and Development (AMED), Core Research for Evolutional Science and Technology (CREST), 2-5-1 Shinmachi, Hirakata, Osaka 573-1010, Japan
| | - Masato Maruyama
- Department of Anatomy, Kansai Medical University, Graduate School of Medicine, Hirakata, Osaka 573-1010, Japan; Faculty of Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
| | - Ryosuke Baba
- Department of Cellular and Functional Biology, Institute of Biomedical Science, Kansai Medical University, Hirakata, Osaka 573-1010, Japan
| | - Chiho Kawashima
- Department of Cellular and Functional Biology, Institute of Biomedical Science, Kansai Medical University, Hirakata, Osaka 573-1010, Japan; Department of Bioscience, Osaka College of High Technology, Osaka 532-003, Japan
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70
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Moeyaert B, Dedecker P. Genetically encoded biosensors based on innovative scaffolds. Int J Biochem Cell Biol 2020; 125:105761. [PMID: 32504671 DOI: 10.1016/j.biocel.2020.105761] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 12/12/2022]
Abstract
Genetically encoded biosensors are indispensable tools for visualizing the spatiotemporal dynamics of analytes or processes in living cells in vitro and in vivo. Their widespread adaptation has gone hand in hand with the development of sensors for new analytes or processes and improved functionality and robustness. In this review, we highlight some of the recent advances in genetically encoded biosensor development, with a special focus on novel and innovative scaffolds that will lead to new possibilities in the future.
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Affiliation(s)
- Benjamien Moeyaert
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Heverlee, Belgium
| | - Peter Dedecker
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Heverlee, Belgium.
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71
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Moutin E, Hemonnot AL, Seube V, Linck N, Rassendren F, Perroy J, Compan V. Procedures for Culturing and Genetically Manipulating Murine Hippocampal Postnatal Neurons. Front Synaptic Neurosci 2020; 12:19. [PMID: 32425766 PMCID: PMC7204911 DOI: 10.3389/fnsyn.2020.00019] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/03/2020] [Indexed: 12/15/2022] Open
Abstract
Neuronal hippocampal cultures are simple and valuable models for studying neuronal function. While embryonic cultures are widely used for different applications, mouse postnatal cultures are still challenging, lack reproducibility and/or exhibit inappropriate neuronal activity. Yet, postnatal cultures have major advantages such as allowing genotyping of pups before culture and reducing the number of experimental animals. Herein we describe a simple and fast protocol for culturing and genetically manipulating hippocampal neurons from P0 to P3 mice. This protocol provides reproducible cultures exhibiting a consistent neuronal development, normal excitatory over inhibitory neuronal ratio and a physiological neuronal activity. We also describe simple and efficient procedures for genetic manipulation of neurons using transfection reagent or lentiviral particles. Overall, this method provides a detailed and validated protocol allowing to explore cellular mechanisms and neuronal activity in postnatal hippocampal neurons in culture.
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Affiliation(s)
- Enora Moutin
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Anne-Laure Hemonnot
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
| | - Vincent Seube
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
| | - Nathalie Linck
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
| | - François Rassendren
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
| | - Julie Perroy
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Vincent Compan
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
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72
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Patel AA, McAlinden N, Mathieson K, Sakata S. Simultaneous Electrophysiology and Fiber Photometry in Freely Behaving Mice. Front Neurosci 2020; 14:148. [PMID: 32153363 PMCID: PMC7047771 DOI: 10.3389/fnins.2020.00148] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/07/2020] [Indexed: 12/27/2022] Open
Abstract
In vivo electrophysiology is the gold standard technique used to investigate sub-second neural dynamics in freely behaving animals. However, monitoring cell-type-specific population activity is not a trivial task. Over the last decade, fiber photometry based on genetically encoded calcium indicators (GECIs) has been widely adopted as a versatile tool to monitor cell-type-specific population activity in vivo. However, this approach suffers from low temporal resolution. Here, we combine these two approaches to monitor both sub-second field potentials and cell-type-specific population activity in freely behaving mice. By developing an economical custom-made system and constructing a hybrid implant of an electrode and a fiber optic cannula, we simultaneously monitor artifact-free mesopontine field potentials and calcium transients in cholinergic neurons across the sleep-wake cycle. We find that mesopontine cholinergic activity co-occurs with sub-second pontine waves, called P-waves, during rapid eye movement sleep. Given the simplicity of our approach, simultaneous electrophysiological recording and cell-type-specific imaging provides a novel and valuable tool for interrogating state-dependent neural circuit dynamics in vivo.
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Affiliation(s)
- Amisha A Patel
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Niall McAlinden
- Department of Physics, Institute of Photonics, SUPA, University of Strathclyde, Glasgow, United Kingdom
| | - Keith Mathieson
- Department of Physics, Institute of Photonics, SUPA, University of Strathclyde, Glasgow, United Kingdom
| | - Shuzo Sakata
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
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73
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Shen Y, Nasu Y, Shkolnikov I, Kim A, Campbell RE. Engineering genetically encoded fluorescent indicators for imaging of neuronal activity: Progress and prospects. Neurosci Res 2020; 152:3-14. [PMID: 31991206 DOI: 10.1016/j.neures.2020.01.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/10/2020] [Accepted: 01/12/2020] [Indexed: 12/31/2022]
Abstract
Genetically encoded fluorescent indicators have transformed the way neuroscientists record neuronal activities and interrogate the nervous system in vivo. In this review, we discuss recent advances and new additions to the toolkit of indicators for calcium ion entry, membrane voltage change, neurotransmitter release, and other neuronal molecular processes. We highlight new engineering approaches for indicator design and development, and identify key areas for future improvement. From molecular tool developers' perspective, we aim to provide practical information for neuroscientists to evaluate and choose the most appropriate indicators for enabling new insights into brain function.
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Affiliation(s)
- Yi Shen
- Department of Chemistry, University of Alberta, Canada
| | - Yusuke Nasu
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Japan
| | | | - Anna Kim
- Department of Chemistry, University of Alberta, Canada
| | - Robert E Campbell
- Department of Chemistry, University of Alberta, Canada; Department of Chemistry, Graduate School of Science, The University of Tokyo, Japan.
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74
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Penzkofer A, Silapetere A, Hegemann P. Photocycle Dynamics of the Archaerhodopsin 3 Based Fluorescent Voltage Sensor QuasAr1. Int J Mol Sci 2019; 21:ijms21010160. [PMID: 31881701 PMCID: PMC6982170 DOI: 10.3390/ijms21010160] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/18/2019] [Accepted: 12/19/2019] [Indexed: 11/16/2022] Open
Abstract
The retinal photocycle dynamics of the fluorescent voltage sensor QuasAr1 (Archaerhodopsin 3 P60S-T80S-D95H-D106H-F161V mutant from Halorubrum sodomense) in pH 8 Tris buffer was studied. The samples were photoexcited to the first absorption band of the protonated retinal Schiff base (PRSB) Ret_580 (absorption maximum at λmax ≈ 580 nm), and the retinal Schiff base photoisomerization and protonation state changes were followed by absorption spectra recordings during light exposure and after light exposure. Ret_580 turned out to be composed of two protonated retinal Schiff base isomers, namely Ret_580I and Ret_580II. Photoexcitation of Ret_580I resulted in barrier-involved isomerization to Ret_540 (quantum yield ≈ 0.056) and subsequent retinal proton release leading to Ret_410 deprotonated retinal Schiff base (RSB). In the dark, Ret_410 partially recovered to Ret_580I and partially stabilized to irreversible Ret_400 due to apoprotein restructuring (Ret_410 lifetime ≈ 2 h). Photoexcitation of Ret_580II resulted in barrier-involved isomerization to Ret_640 (quantum yield ≈ 0.00135) and subsequent deprotonation to Ret_370 (RSB). In the dark, Ret_370 partially recovered to Ret_580II and partially stabilized to irreversible Ret_350 due to apoprotein restructuring (Ret_370 lifetime ≈ 10 h). Photocycle schemes and reaction coordinate diagrams for Ret_580I and Ret_580II were developed and photocyle parameters were determined.
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Affiliation(s)
- Alfons Penzkofer
- Fakultät für Physik, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
- Correspondence: ; Tel.: +49-941-943-2107
| | - Arita Silapetere
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany; (A.S.); (P.H.)
| | - Peter Hegemann
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany; (A.S.); (P.H.)
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75
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Xu Y, Deng M, Zhang S, Yang J, Peng L, Chu J, Zou P. Imaging Neuronal Activity with Fast and Sensitive Red-Shifted Electrochromic FRET Indicators. ACS Chem Neurosci 2019; 10:4768-4775. [PMID: 31725259 DOI: 10.1021/acschemneuro.9b00501] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Genetically encoded voltage indicators (GEVIs) allow optical recording of neuronal activities with high spatial resolution. While most existing GEVIs emit in the green range, red-shifted GEVIs are highly sought after because they would enable simultaneous stimulation and recording of neuronal activities when paired with optogenetic actuators, or two-color imaging of signaling and neuronal activities when used along with GFP-based indicators. In this study, we present several improved red-shifted GEVIs based on the electrochromic Förster resonance energy transfer (eFRET) between orange/red fluorescent proteins/dyes and rhodopsin mutants. Through structure-guided mutagenesis and cell-based sensitivity screening, we identified a mutant rhodopsin with a single mutation that exhibited more than 2-fold improvement in voltage sensitivity. Notably, this mutation has been independently discovered by Pieribone et al. ( Pieribone, V. A. et al. Nat Methods 2018 , 15 ( 12 ), 1108 - 1116 ). In cultured rat hippocampal neurons, our sensors faithfully reported action potential waveforms and subthreshold activities. We also demonstrated that this mutation could enhance the sensitivity of hybrid indicators, thus providing insights for future development.
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Affiliation(s)
- Yongxian Xu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Mengying Deng
- Laboratory for Biomedical Optics and Molecular Imaging, CAS Key Laboratory of Health Informatics, Shenzhen Institute of Synthetic Biology, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Shu Zhang
- Laboratory for Biomedical Optics and Molecular Imaging, CAS Key Laboratory of Health Informatics, Shenzhen Institute of Synthetic Biology, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Junqi Yang
- Peking-Tsinghua-NIBS Joint Graduate Program, Peking University, Beijing 100871, China
| | - Luxin Peng
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Jun Chu
- Laboratory for Biomedical Optics and Molecular Imaging, CAS Key Laboratory of Health Informatics, Shenzhen Institute of Synthetic Biology, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Peng Zou
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Beijing, China
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76
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Hofmann UAT, Fabritius A, Rebling J, Estrada H, Deán-Ben XL, Griesbeck O, Razansky D. High-Throughput Platform for Optoacoustic Probing of Genetically Encoded Calcium Ion Indicators. iScience 2019; 22:400-408. [PMID: 31812810 PMCID: PMC6911978 DOI: 10.1016/j.isci.2019.11.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 11/15/2019] [Accepted: 11/19/2019] [Indexed: 12/15/2022] Open
Abstract
Functional optoacoustic (OA) imaging assisted with genetically encoded calcium ion indicators (GECIs) holds promise for imaging large-scale neuronal activity at depths and spatiotemporal resolutions not attainable with existing optical microscopic techniques. However, currently available GECIs optimized for fluorescence (FL) imaging lack sufficient contrast for OA imaging and respond at wavelengths having limited penetration into the mammalian brain. Here we present an imaging platform capable of rapid assessment and cross-validation between OA and FL responses of sensor proteins expressed in Escherichia coli colonies. The screening system features optimized pulsed light excitation combined with ultrasensitive ultrasound detection to mitigate photobleaching while further allowing the dynamic characterization of calcium ion responses with millisecond precision. Targeted probing of up to six individual colonies per second in both calcium-loaded and calcium-unloaded states was possible with the system. The new platform greatly facilitates optimization of absorption-based labels, thus setting the stage for directed evolution of OA GECIs.
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Affiliation(s)
- Urs A T Hofmann
- Institute of Pharmacology and Toxicology and Faculty of Medicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Institute for Biomedical Engineering and Department of Information Technology and Electrical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland
| | - Arne Fabritius
- Tools for Bio-Imaging, Max Planck Institute, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Johannes Rebling
- Institute of Pharmacology and Toxicology and Faculty of Medicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Institute for Biomedical Engineering and Department of Information Technology and Electrical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland
| | - Héctor Estrada
- Institute of Pharmacology and Toxicology and Faculty of Medicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Institute for Biomedical Engineering and Department of Information Technology and Electrical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland
| | - X Luís Deán-Ben
- Institute of Pharmacology and Toxicology and Faculty of Medicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Institute for Biomedical Engineering and Department of Information Technology and Electrical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland
| | - Oliver Griesbeck
- Tools for Bio-Imaging, Max Planck Institute, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Daniel Razansky
- Institute of Pharmacology and Toxicology and Faculty of Medicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Institute for Biomedical Engineering and Department of Information Technology and Electrical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland.
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77
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Lecoq J, Orlova N, Grewe BF. Wide. Fast. Deep: Recent Advances in Multiphoton Microscopy of In Vivo Neuronal Activity. J Neurosci 2019; 39:9042-9052. [PMID: 31578235 PMCID: PMC6855689 DOI: 10.1523/jneurosci.1527-18.2019] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 09/27/2019] [Accepted: 09/27/2019] [Indexed: 01/04/2023] Open
Abstract
Multiphoton microscopy (MPM) has emerged as one of the most powerful and widespread technologies to monitor the activity of neuronal networks in awake, behaving animals over long periods of time. MPM development spanned across decades and crucially depended on the concurrent improvement of calcium indicators that report neuronal activity as well as surgical protocols, head fixation approaches, and innovations in optics and microscopy technology. Here we review the last decade of MPM development and highlight how in vivo imaging has matured and diversified, making it now possible to concurrently monitor thousands of neurons across connected brain areas or, alternatively, small local networks with sampling rates in the kilohertz range. This review includes different laser scanning approaches, such as multibeam technologies as well as recent developments to image deeper into neuronal tissues using new, long-wavelength laser sources. As future development will critically depend on our ability to resolve and discriminate individual neuronal spikes, we will also describe a simple framework that allows performing quantitative comparisons between the reviewed MPM instruments. Finally, we provide our own opinion on how the most recent MPM developments can be leveraged at scale to enable the next generation of discoveries in brain function.
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Affiliation(s)
- Jérôme Lecoq
- Allen Institute for Brain Science, Seattle 98109, Washington,
| | - Natalia Orlova
- Allen Institute for Brain Science, Seattle 98109, Washington
| | - Benjamin F Grewe
- Institute of Neuroinformatics, UZH and ETH Zurich, Zurich 8057, Switzerland
- Department of Electrical Engineering and Information Technology, ETH Zurich, Zurich 8092, Switzerland, and
- Faculty of Sciences, University of Zurich, Zurich 8057, Switzerland
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78
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Beck C, Zhang D, Gong Y. Enhanced genetically encoded voltage indicators advance their applications in neuroscience. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2019; 12:111-117. [PMID: 32864526 DOI: 10.1016/j.cobme.2019.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Genetically encoded voltage indicators report membrane voltage with high spatiotemporal resolution. Extensive recent efforts to improve the GEVIs' brightness, sensitivity, and kinetics have greatly increased the GEVIs' signal-to-noise performance over ten-fold and lowered their response time to the sub-millisecond regime. Such capabilities have broadened the GEVIs' ability to measure membrane voltage of neural populations at cellular resolution in vitro and in vivo, all at high speeds. The GEVIs' high voltage fidelity and fast response have revealed novel physiological phenomena in multiple neuroscientific applications. Such applications portend future targeted studies of voltage activity that take advantage of the GEVIs' ability to report rapid dynamics from genetically-targeted neural populations.
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Affiliation(s)
- Connor Beck
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Diming Zhang
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Yiyang Gong
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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79
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Optical voltage imaging in neurons: moving from technology development to practical tool. Nat Rev Neurosci 2019; 20:719-727. [PMID: 31705060 DOI: 10.1038/s41583-019-0231-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2019] [Indexed: 12/13/2022]
Abstract
A central goal in neuroscience is to determine how the brain's neuronal circuits generate perception, cognition and emotions and how these lead to appropriate behavioural actions. A methodological platform based on genetically encoded voltage indicators (GEVIs) that enables the monitoring of large-scale circuit dynamics has brought us closer to this ambitious goal. This Review provides an update on the current state of the art and the prospects of emerging optical GEVI imaging technologies.
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80
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Beck C, Gong Y. A high-speed, bright, red fluorescent voltage sensor to detect neural activity. Sci Rep 2019; 9:15878. [PMID: 31685893 PMCID: PMC6828731 DOI: 10.1038/s41598-019-52370-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/16/2019] [Indexed: 11/27/2022] Open
Abstract
Genetically encoded voltage indicators (GEVIs) have emerged as a technology to optically record neural activity with genetic specificity and millisecond-scale temporal resolution using fluorescence microscopy. GEVIs have demonstrated ultra-fast kinetics and high spike detection fidelity in vivo, but existing red-fluorescent voltage indicators fall short of the response and brightness achieved by green fluorescent protein-based sensors. Furthermore, red-fluorescent GEVIs suffer from incomplete spectral separation from green sensors and blue-light-activated optogenetic actuators. We have developed Ace-mScarlet, a red fluorescent GEVI that fuses Ace2N, a voltage-sensitive inhibitory rhodopsin, with mScarlet, a bright red fluorescent protein (FP). Through fluorescence resonance energy transfer (FRET), our sensor detects changes in membrane voltage with high sensitivity and brightness and has kinetics comparable to the fastest green fluorescent sensors. Ace-mScarlet's red-shifted absorption and emission spectra facilitate virtually complete spectral separation when used in combination with green-fluorescent sensors or with blue-light-sensitive sensors and rhodopsins. This spectral separation enables both simultaneous imaging in two separate wavelength channels and high-fidelity voltage recordings during simultaneous optogenetic perturbation.
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Affiliation(s)
- Connor Beck
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Yiyang Gong
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
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81
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Barson D, Hamodi AS, Shen X, Lur G, Constable RT, Cardin JA, Crair MC, Higley MJ. Simultaneous mesoscopic and two-photon imaging of neuronal activity in cortical circuits. Nat Methods 2019; 17:107-113. [PMID: 31686040 PMCID: PMC6946863 DOI: 10.1038/s41592-019-0625-2] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 09/30/2019] [Indexed: 12/20/2022]
Abstract
Spontaneous and sensory-evoked activity propagates across varying spatial scales in the mammalian cortex, but technical challenges have limited conceptual links between the function of local neuronal circuits and brain-wide network dynamics. We present a method for simultaneous cellular-resolution two-photon calcium imaging of a local microcircuit and mesoscopic widefield calcium imaging of the entire cortical mantle in awake mice. Our multi-scale approach employs an orthogonal axis design where the mesoscopic objective is oriented above the brain and the two-photon objective is oriented horizontally, with imaging performed through a microprism. We also introduce a viral method for robust and widespread gene delivery in the mouse brain. These approaches allow us to identify the behavioral state-dependent functional connectivity of pyramidal neurons and vasoactive intestinal peptide (VIP)-expressing interneurons with long-range cortical networks. Our novel imaging system provides a powerful strategy for investigating cortical architecture across a wide range of spatial scales. Further information on research design is available in the Life Sciences Reporting Summary linked to this article.
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Affiliation(s)
- Daniel Barson
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA.,Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT, USA.,MD/PhD Program, Yale School of Medicine, New Haven, CT, USA
| | - Ali S Hamodi
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Xilin Shen
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Gyorgy Lur
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA.,Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
| | - R Todd Constable
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT, USA.,Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA.,Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Jessica A Cardin
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA.,Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Michael C Crair
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA. .,Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, USA. .,Department of Ophthalmology and Visual Science, Yale School of Medicine, New Haven, CT, USA.
| | - Michael J Higley
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA. .,Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, USA. .,Program in Cellular Neuroscience, Neurodegeneration and Repair, New Haven, CT, USA.
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82
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83
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Abstract
As a "holy grail" of neuroscience, optical imaging of membrane potential could enable high resolution measurements of spiking and synaptic activity in neuronal populations. This has been partly achieved using organic voltage-sensitive dyes in vitro, or in invertebrate preparations yet unspecific staining has prevented single-cell resolution measurements from mammalian preparations in vivo. The development of genetically encoded voltage indicators (GEVIs) and chemogenetic sensors has enabled targeting voltage indicators to plasma membranes and selective neuronal populations. Here, we review recent advances in the design and use of genetic voltage indicators and discuss advantages and disadvantages of three classes of them. Although genetic voltage indicators could revolutionize neuroscience, there are still significant challenges, particularly two-photon performance. To overcome them may require cross-disciplinary collaborations, team effort, and sustained support by large-scale research initiatives.
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Affiliation(s)
- Yuki Bando
- Neurotechnology Center, Department Biological Sciences, Columbia University, 550 W 120th Street, New York, NY, 10027, USA
- Present address: Department Organ and Tissue Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Christiane Grimm
- Neurotechnology Center, Department Biological Sciences, Columbia University, 550 W 120th Street, New York, NY, 10027, USA
| | - Victor H Cornejo
- Neurotechnology Center, Department Biological Sciences, Columbia University, 550 W 120th Street, New York, NY, 10027, USA
| | - Rafael Yuste
- Neurotechnology Center, Department Biological Sciences, Columbia University, 550 W 120th Street, New York, NY, 10027, USA.
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84
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Rhodopsin-based voltage imaging tools for use in muscles and neurons of Caenorhabditis elegans. Proc Natl Acad Sci U S A 2019; 116:17051-17060. [PMID: 31371514 PMCID: PMC6708366 DOI: 10.1073/pnas.1902443116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuronal and other excitable cell activity is characterized by alteration in membrane voltage, while intracellular Ca2+ levels and transmitter release are affected downstream of electrical activity. Thus, the most direct way of monitoring neuronal activity is by membrane voltage. Electrophysiology is demanding for multiple cells or cell ensembles and difficult to use in live animals, thus imaging methods are desirable. Yet, genetically encoded voltage indicators fell behind Ca2+ indicators until recently, when microbial rhodopsins and derivatives were introduced as genetically encoded voltage indicators. We evaluated rhodopsin tools for voltage imaging in muscles and neurons of Caenorhabditis elegans, a prime animal model in neuro- and cell biology, showing robust performance and the ability to characterize genetic mutants. Genetically encoded voltage indicators (GEVIs) based on microbial rhodopsins utilize the voltage-sensitive fluorescence of all-trans retinal (ATR), while in electrochromic FRET (eFRET) sensors, donor fluorescence drops when the rhodopsin acts as depolarization-sensitive acceptor. In recent years, such tools have become widely used in mammalian cells but are less commonly used in invertebrate systems, mostly due to low fluorescence yields. We systematically assessed Arch(D95N), Archon, QuasAr, and the eFRET sensors MacQ-mCitrine and QuasAr-mOrange, in the nematode Caenorhabditis elegans. ATR-bearing rhodopsins reported on voltage changes in body wall muscles (BWMs), in the pharynx, the feeding organ [where Arch(D95N) showed approximately 128% ΔF/F increase per 100 mV], and in neurons, integrating circuit activity. ATR fluorescence is very dim, yet, using the retinal analog dimethylaminoretinal, it was boosted 250-fold. eFRET sensors provided sensitivities of 45 to 78% ΔF/F per 100 mV, induced by BWM action potentials, and in pharyngeal muscle, measured in simultaneous optical and sharp electrode recordings, MacQ-mCitrine showed approximately 20% ΔF/F per 100 mV. All sensors reported differences in muscle depolarization induced by a voltage-gated Ca2+-channel mutant. Optogenetically evoked de- or hyperpolarization of motor neurons increased or eliminated action potential activity and caused a rise or drop in BWM sensor fluorescence. Finally, we analyzed voltage dynamics across the entire pharynx, showing uniform depolarization but compartmentalized repolarization of anterior and posterior parts. Our work establishes all-optical, noninvasive electrophysiology in live, intact C. elegans.
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85
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Park J, Kuo Y, Li J, Huang YL, Miller EW, Weiss S. Improved Surface Functionalization and Characterization of Membrane-Targeted Semiconductor Voltage Nanosensors. J Phys Chem Lett 2019; 10:3906-3913. [PMID: 31241960 DOI: 10.1021/acs.jpclett.9b01258] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Type-II ZnSe/CdS voltage-sensing seeded nanorods (vsNRs) were functionalized with α-helical peptides and zwitterionic-decorated lipoic acids (zw-LAs). Specific membrane targeting with high loading efficiency and minimal nonspecific binding was achieved. These vsNRs display quantum yield (QY) modulation as a function of membrane potential (MP) changes, as demonstrated at the ensemble level for (i) vesicles treated with valinomycin and (ii) wild-type HEK cells under alternating buffers with different [K+]. ΔF/F of ∼ 1% was achieved.
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Affiliation(s)
- Joonhyuck Park
- Department of Chemistry and Biochemistry , University of California Los Angeles , Los Angeles , California 90095 , United States
| | - Yung Kuo
- Department of Chemistry and Biochemistry , University of California Los Angeles , Los Angeles , California 90095 , United States
| | - Jack Li
- Department of Chemistry and Biochemistry , University of California Los Angeles , Los Angeles , California 90095 , United States
| | - Yi-Lin Huang
- Department of Chemistry , Department Molecular & Cell Biology , and Helen Wills Neuroscience Institute , University of California Berkeley , Berkeley , California 94720 , United States
| | - Evan W Miller
- Department of Chemistry , Department Molecular & Cell Biology , and Helen Wills Neuroscience Institute , University of California Berkeley , Berkeley , California 94720 , United States
| | - Shimon Weiss
- Department of Chemistry and Biochemistry , University of California Los Angeles , Los Angeles , California 90095 , United States
- California NanoSystems Institute , University of California Los Angeles , Los Angeles , California 90095 , United States
- Department of Physiology , University of California Los Angeles , Los Angeles , California 90095 , United States
- Department of Physics, Institute for Nanotechnology and Advanced Materials , Bar-Ilan University , Ramat-Gan 52900 , Israel
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86
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Kost LA, Ivanova VO, Balaban PM, Lukyanov KA, Nikitin ES, Bogdanov AM. Red Fluorescent Genetically Encoded Voltage Indicators with Millisecond Responsiveness. SENSORS (BASEL, SWITZERLAND) 2019; 19:E2982. [PMID: 31284557 PMCID: PMC6651345 DOI: 10.3390/s19132982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 01/09/2023]
Abstract
Genetically encoded fluorescent indicators typically consist of the sensitive and reporter protein domains connected with the amino acid linkers. The final performance of a particular indicator may depend on the linker length and composition as strong as it depends on the both domains nature. Here we aimed to optimize interdomain linkers in VSD-FR189-188-a recently described red fluorescent protein-based voltage indicator. We have tested 13 shortened linker versions and monitored the dynamic range, response speed and polarity of the corresponding voltage indicator variants. While the new indicators didn't show a contrast enhancement, some of them carrying very short interdomain linkers responded 25-fold faster than the parental VSD-FR189-188. Also we found the critical linker length at which fluorescence response to voltage shift changes its polarity from negative to positive slope. Our observations thus make an important contribution to the designing principles of the fluorescent protein-derived voltage indicators.
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Affiliation(s)
- Liubov A Kost
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia
| | - Violetta O Ivanova
- Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia
| | - Pavel M Balaban
- Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia
| | - Konstantin A Lukyanov
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Evgeny S Nikitin
- Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia
| | - Alexey M Bogdanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia.
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87
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Panzera LC, Hoppa MB. Genetically Encoded Voltage Indicators Are Illuminating Subcellular Physiology of the Axon. Front Cell Neurosci 2019; 13:52. [PMID: 30881287 PMCID: PMC6406964 DOI: 10.3389/fncel.2019.00052] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/04/2019] [Indexed: 12/13/2022] Open
Abstract
Everything we see and do is regulated by electrical signals in our nerves and muscle. Ion channels are crucial for sensing and generating electrical signals. Two voltage-dependent conductances, Na+ and K+, form the bedrock of the electrical impulse in the brain known as the action potential. Several classes of mammalian neurons express combinations of nearly 100 different varieties of these two voltage-dependent channels and their subunits. Not surprisingly, this variability orchestrates a diversity of action potential shapes and firing patterns that have been studied in detail at neural somata. A remarkably understudied phenomena exists in subcellular compartments of the axon, where action potentials initiate synaptic transmission. Ion channel research was catalyzed by the invention of glass electrodes to measure electrical signals in cell membranes, however, progress in the field of neurobiology has been stymied by the fact that most axons in the mammalian CNS are far too small and delicate for measuring ion channel function with electrodes. These quantitative measurements of membrane voltage can be achieved within the axon using light. A revolution of optical voltage sensors has enabled exploring important questions of how ion channels regulate axon physiology and synaptic transmission. In this review we will consider advantages and disadvantages of different fluorescent voltage indicators and discuss particularly relevant questions that these indicators can elucidate for understanding the crucial relationship between action potentials and synaptic transmission.
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Affiliation(s)
| | - Michael B. Hoppa
- Department of Biological Sciences, Dartmouth College, Hanover, NH, United States
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88
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In-Vitro Characterization of mCerulean3_mRuby3 as a Novel FRET Pair with Favorable Bleed-Through Characteristics. BIOSENSORS-BASEL 2019; 9:bios9010033. [PMID: 30823443 PMCID: PMC6468510 DOI: 10.3390/bios9010033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/12/2019] [Accepted: 02/19/2019] [Indexed: 11/28/2022]
Abstract
In previous studies, we encountered substantial problems using the CFP_YFP Förster resonance energy transfer (FRET) pair to analyze protein proximity in the endoplasmic reticulum of live cells. Bleed-through of the donor emission into the FRET channel and overlap of the FRET emission wavelength with highly variable cellular autofluorescence significantly compromised the sensitivity of our analyses. Here, we propose mCerulean3 and mRuby3 as a new FRET pair to potentially overcome these problems. Fusion of the two partners with a trypsin-cleavable linker allowed the direct comparison of the FRET signal characteristics of the associated partners with those of the completely dissociated partners. We compared our new FRET pair with the canonical CFP_YFP and the more recent mClover3_mRuby3 pairs and found that, despite a lower total FRET signal intensity, the novel pair had a significantly better signal to noise ratio due to lower donor emission bleed-through. This and the fact that the mRuby3 emission spectrum did not overlap with that of common cellular autofluorescence renders the mCerulean3_mRuby3 FRET pair a promising alternative to the common CFP_YFP FRET pair for the interaction analysis of membrane proteins in living cells.
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89
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Kannan M, Vasan G, Pieribone VA. Optimizing Strategies for Developing Genetically Encoded Voltage Indicators. Front Cell Neurosci 2019; 13:53. [PMID: 30863283 PMCID: PMC6399427 DOI: 10.3389/fncel.2019.00053] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 02/04/2019] [Indexed: 01/23/2023] Open
Abstract
Genetically encoded optical indicators of neuronal activity enable unambiguous recordings of input-output activity patterns from identified cells in intact circuits. Among them, genetically encoded voltage indicators (GEVIs) offer additional advantages over calcium indicators as they are direct sensors of membrane potential and can adeptly report subthreshold events and hyperpolarization. Here, we outline the major GEVI designs and give an account of properties that need to be carefully optimized during indicator engineering. While designing the ideal GEVI, one should keep in mind aspects such as membrane localization, signal size, signal-to-noise ratio, kinetics and voltage dependence of optical responses. Using ArcLight and derivatives as prototypes, we delineate how a probe should be optimized for the former properties and developed along other areas in a need-based manner. Finally, we present an overview of the GEVI engineering process and lend an insight into their discovery, delivery and diagnosis.
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Affiliation(s)
- Madhuvanthi Kannan
- The John B. Pierce Laboratory, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Ganesh Vasan
- The John B. Pierce Laboratory, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Vincent A Pieribone
- The John B. Pierce Laboratory, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Neuroscience, Yale School of Medicine, Yale University, New Haven, CT, United States
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90
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Advances in Engineering and Application of Optogenetic Indicators for Neuroscience. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9030562] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Our ability to investigate the brain is limited by available technologies that can record biological processes in vivo with suitable spatiotemporal resolution. Advances in optogenetics now enable optical recording and perturbation of central physiological processes within the intact brains of model organisms. By monitoring key signaling molecules noninvasively, we can better appreciate how information is processed and integrated within intact circuits. In this review, we describe recent efforts engineering genetically-encoded fluorescence indicators to monitor neuronal activity. We summarize recent advances of sensors for calcium, potassium, voltage, and select neurotransmitters, focusing on their molecular design, properties, and current limitations. We also highlight impressive applications of these sensors in neuroscience research. We adopt the view that advances in sensor engineering will yield enduring insights on systems neuroscience. Neuroscientists are eager to adopt suitable tools for imaging neural activity in vivo, making this a golden age for engineering optogenetic indicators.
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91
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92
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Abstract
Fluorescent probes that indicate biologically important quantities are widely used for many different types of biological experiments across life sciences. During recent years, limitations of small molecule-based indicators have been overcome by the development of genetically encoded indicators. Here we focus on fluorescent calcium and voltage indicators and point to their applications mainly in neurosciences.
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Greenwald EC, Mehta S, Zhang J. Genetically Encoded Fluorescent Biosensors Illuminate the Spatiotemporal Regulation of Signaling Networks. Chem Rev 2018; 118:11707-11794. [PMID: 30550275 PMCID: PMC7462118 DOI: 10.1021/acs.chemrev.8b00333] [Citation(s) in RCA: 302] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cellular signaling networks are the foundation which determines the fate and function of cells as they respond to various cues and stimuli. The discovery of fluorescent proteins over 25 years ago enabled the development of a diverse array of genetically encodable fluorescent biosensors that are capable of measuring the spatiotemporal dynamics of signal transduction pathways in live cells. In an effort to encapsulate the breadth over which fluorescent biosensors have expanded, we endeavored to assemble a comprehensive list of published engineered biosensors, and we discuss many of the molecular designs utilized in their development. Then, we review how the high temporal and spatial resolution afforded by fluorescent biosensors has aided our understanding of the spatiotemporal regulation of signaling networks at the cellular and subcellular level. Finally, we highlight some emerging areas of research in both biosensor design and applications that are on the forefront of biosensor development.
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Affiliation(s)
- Eric C Greenwald
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Sohum Mehta
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Jin Zhang
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
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