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Strauss J, Deng L, Gao S, Toseland A, Bachy C, Zhang C, Kirkham A, Hopes A, Utting R, Joest EF, Tagliabue A, Löw C, Worden AZ, Nagel G, Mock T. Plastid-localized xanthorhodopsin increases diatom biomass and ecosystem productivity in iron-limited surface oceans. Nat Microbiol 2023; 8:2050-2066. [PMID: 37845316 PMCID: PMC10627834 DOI: 10.1038/s41564-023-01498-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 09/12/2023] [Indexed: 10/18/2023]
Abstract
Microbial rhodopsins are photoreceptor proteins that convert light into biological signals or energy. Proteins of the xanthorhodopsin family are common in eukaryotic photosynthetic plankton including diatoms. However, their biological role in these organisms remains elusive. Here we report on a xanthorhodopsin variant (FcR1) isolated from the polar diatom Fragilariopsis cylindrus. Applying a combination of biophysical, biochemical and reverse genetics approaches, we demonstrate that FcR1 is a plastid-localized proton pump which binds the chromophore retinal and is activated by green light. Enhanced growth of a Thalassiora pseudonana gain-of-function mutant expressing FcR1 under iron limitation shows that the xanthorhodopsin proton pump supports growth when chlorophyll-based photosynthesis is iron-limited. The abundance of xanthorhodopsin transcripts in natural diatom communities of the surface oceans is anticorrelated with the availability of dissolved iron. Thus, we propose that these proton pumps convey a fitness advantage in regions where phytoplankton growth is limited by the availability of dissolved iron.
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Affiliation(s)
- Jan Strauss
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK.
- Ocean EcoSystems Biology Unit, RD3, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany.
- European Molecular Biology Laboratory (EMBL), Hamburg Unit c/o Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany.
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany.
- German Maritime Centre, Hamburg, Germany.
| | - Longji Deng
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Shiqiang Gao
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Wuerzburg, Germany
| | - Andrew Toseland
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Charles Bachy
- Ocean EcoSystems Biology Unit, RD3, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Sorbonne Université, CNRS, FR2424, Station biologique de Roscoff, Roscoff, France
| | - Chong Zhang
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Wuerzburg, Germany
| | - Amy Kirkham
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Amanda Hopes
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Robert Utting
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Eike F Joest
- Department of Biology, Biocenter, University of Würzburg, Wuerzburg, Germany
| | | | - Christian Löw
- European Molecular Biology Laboratory (EMBL), Hamburg Unit c/o Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
| | - Alexandra Z Worden
- Ocean EcoSystems Biology Unit, RD3, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
- Marine Biological Laboratory, Woods Hole, MA, USA
| | - Georg Nagel
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Wuerzburg, Germany
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK.
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Katada Y, Yoshida K, Serizawa N, Lee D, Kobayashi K, Negishi K, Okano H, Kandori H, Tsubota K, Kurihara T. Highly sensitive visual restoration and protection via ectopic expression of chimeric rhodopsin in mice. iScience 2023; 26:107716. [PMID: 37720108 PMCID: PMC10504486 DOI: 10.1016/j.isci.2023.107716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/22/2023] [Accepted: 08/22/2023] [Indexed: 09/19/2023] Open
Abstract
Photoreception requires amplification by mammalian rhodopsin through G protein activation, which requires a visual cycle. To achieve this in retinal gene therapy, we incorporated human rhodopsin cytoplasmic loops into Gloeobacter rhodopsin, thereby generating Gloeobacter and human chimeric rhodopsin (GHCR). In a murine model of inherited retinal degeneration, we induced retinal GHCR expression by intravitreal injection of a recombinant adeno-associated virus vector. Retinal explant and visual thalamus electrophysiological recordings, behavioral tests, and histological analysis showed that GHCR restored dim-environment vision and prevented the progression of retinal degeneration. Thus, GHCR may be a potent clinical tool for the treatment of retinal disorders.
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Affiliation(s)
- Yusaku Katada
- Laboratory of Photobiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Kazuho Yoshida
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Aichi 466-0061, Japan
| | - Naho Serizawa
- Laboratory of Photobiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Nutritional Sciences, Toyo University, Kita-ku, Tokyo 115-8650, Japan
| | - Deokho Lee
- Laboratory of Photobiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, Center for Genetic Analysis of Behavior, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan
| | - Kazuno Negishi
- Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Aichi 466-0061, Japan
| | - Kazuo Tsubota
- Tsubota Laboratory, Inc., Shinjuku-ku, Tokyo 160-0016, Japan
| | - Toshihide Kurihara
- Laboratory of Photobiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
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3
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Bühl E, Resler T, Lam R, Asido M, Bamberg E, Schlesinger R, Bamann C, Heberle J, Wachtveitl J. Assessing the Role of R120 in the Gating of CrChR2 by Time-Resolved Spectroscopy from Femtoseconds to Seconds. J Am Chem Soc 2023; 145:21832-21840. [PMID: 37773976 DOI: 10.1021/jacs.3c05399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2023]
Abstract
The light-gated ion channel channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2) is the most frequently used optogenetic tool in neurosciences. However, the precise molecular mechanism of the channel opening and the correlation among retinal isomerization, the photocycle, and the channel activity of the protein are missing. Here, we present electrophysiological and spectroscopic investigations on the R120H variant of CrChR2. R120 is a key residue in an extended network linking the retinal chromophore to several gates of the ion channel. We show that despite the deficient channel activity, the photocycle of the variant is intact. In a comparative study for R120H and the wild type, we resolve the vibrational changes in the spectral range of the retinal and amide I bands across the time range from femtoseconds to seconds. Analysis of the amide I mode reveals a significant impairment of the ultrafast protein response after retinal excitation. We conclude that channel opening in CrChR2 is prepared immediately after retinal excitation. Additionally, chromophore isomerization is essential for both photocycle and channel activities, although both processes can occur independently.
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Affiliation(s)
- Elena Bühl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt am Main, Max-von-Laue Strasse 7, 60438 Frankfurt, Germany
| | - Tom Resler
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Rebecca Lam
- Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany
| | - Marvin Asido
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt am Main, Max-von-Laue Strasse 7, 60438 Frankfurt, Germany
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany
| | - Ramona Schlesinger
- Department of Physics, Genetic Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Christian Bamann
- Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany
| | - Joachim Heberle
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt am Main, Max-von-Laue Strasse 7, 60438 Frankfurt, Germany
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Gene-independent therapeutic interventions to maintain and restore light sensitivity in degenerating photoreceptors. Prog Retin Eye Res 2022; 90:101065. [PMID: 35562270 DOI: 10.1016/j.preteyeres.2022.101065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/08/2022] [Accepted: 04/18/2022] [Indexed: 12/14/2022]
Abstract
Neurodegenerative retinal diseases are a prime cause of blindness in industrialized countries. In many cases, there are no therapeutic treatments, although they are essential to improve patients' quality of life. A set of disease-causing genes, which primarily affect photoreceptors, has already been identified and is of major interest for developing gene therapies. Nevertheless, depending on the nature and the state of the disease, gene-independent strategies are needed. Various strategies to halt disease progression or maintain function of the retina are under research. These therapeutic interventions include neuroprotection, direct reprogramming of affected photoreceptors, the application of non-coding RNAs, the generation of artificial photoreceptors by optogenetics and cell replacement strategies. During recent years, major breakthroughs have been made such as the first optogenetic application to a blind patient whose visual function partially recovered by targeting retinal ganglion cells. Also, RPE cell transplantation therapies are under clinical investigation and show great promise to improve visual function in blind patients. These cells are generated from human stem cells. Similar therapies for replacing photoreceptors are extensively tested in pre-clinical models. This marks just the start of promising new cures taking advantage of developments in the areas of genetic engineering, optogenetics, and stem-cell research. In this review, we present the recent therapeutic advances of gene-independent approaches that are currently under clinical evaluation. Our main focus is on photoreceptors as these sensory cells are highly vulnerable to degenerative diseases, and are crucial for light detection.
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Abstract
Optogenetics has revolutionized not only neuroscience but also had an impact on muscle physiology and cell biology. Rhodopsin-based optogenetics started with the discovery of the light-gated cation channels, called channelrhodopsins. Together with the light-driven ion pumps, these channels allow light-mediated control of electrically excitable cells in culture tissue and living animals. They can be activated (depolarized) or silenced (hyperpolarized) by light with incomparably high spatiotemporal resolution. Optogenetics allows the light manipulation of cells under electrode-free conditions in a minimally invasive manner. Through modern genetic techniques, virus-induced transduction can be performed with extremely high cell specificity in tissue and living animals, allowing completely new approaches for analyzing neural networks, behavior studies, and investigations of neurodegenerative diseases. First clinical trials for the optogenetic recovery of vision are underway.This chapter provides a comprehensive description of the structure and function of the different light-gated channels and some new light-activated ion pumps. Some of them already play an essential role in optogenetics while others are supposed to become important tools for more specialized applications in the future.At the moment, a large number of publications are available concerning intrinsic mechanisms of microbial rhodopsins. Mostly they describe CrChR2 and its variants, as CrChR2 is still the most prominent optogenetic tool. Therefore, many biophysically and biochemically oriented groups contributed to the overwhelming mass of information on this unique ion channel's molecular mechanism. In this context, the function of new optogenetic tools is discussed, which is essential for rational optimization of the optogenetic approach for an eventual biomedical application. The comparison of the effectivity of ion pumps versus ion channels is discussed as well.Applications of rhodopsins-based optogenetic tools are also discussed in the chapter. Because of the enormous number of these applications in neuroscience, only exemplary studies on cell culture neural tissue, muscle physiology, and remote control of animal behavior are presented.
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Affiliation(s)
- Alexey Alekseev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Valentin Gordeliy
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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Panzer S, Zhang C, Konte T, Bräuer C, Diemar A, Yogendran P, Yu-Strzelczyk J, Nagel G, Gao S, Terpitz U. Modified Rhodopsins From Aureobasidium pullulans Excel With Very High Proton-Transport Rates. Front Mol Biosci 2021; 8:750528. [PMID: 34790700 PMCID: PMC8591190 DOI: 10.3389/fmolb.2021.750528] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/16/2021] [Indexed: 11/19/2022] Open
Abstract
Aureobasidium pullulans is a black fungus that can adapt to various stressful conditions like hypersaline, acidic, and alkaline environments. The genome of A. pullulans exhibits three genes coding for putative opsins ApOps1, ApOps2, and ApOps3. We heterologously expressed these genes in mammalian cells and Xenopus oocytes. Localization in the plasma membrane was greatly improved by introducing additional membrane trafficking signals at the N-terminus and the C-terminus. In patch-clamp and two-electrode-voltage clamp experiments, all three proteins showed proton pump activity with maximal activity in green light. Among them, ApOps2 exhibited the most pronounced proton pump activity with current amplitudes occasionally extending 10 pA/pF at 0 mV. Proton pump activity was further supported in the presence of extracellular weak organic acids. Furthermore, we used site-directed mutagenesis to reshape protein functions and thereby implemented light-gated proton channels. We discuss the difference to other well-known proton pumps and the potential of these rhodopsins for optogenetic applications.
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Affiliation(s)
- Sabine Panzer
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Chong Zhang
- Department of Neurophysiology, Physiological Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Tilen Konte
- Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Ljubljana, Slovenia
| | - Celine Bräuer
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Anne Diemar
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Parathy Yogendran
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Jing Yu-Strzelczyk
- Department of Neurophysiology, Physiological Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Georg Nagel
- Department of Neurophysiology, Physiological Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Shiqiang Gao
- Department of Neurophysiology, Physiological Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Ulrich Terpitz
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
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Yang S, Constantin OM, Sachidanandan D, Hofmann H, Kunz TC, Kozjak-Pavlovic V, Oertner TG, Nagel G, Kittel RJ, Gee CE, Gao S. PACmn for improved optogenetic control of intracellular cAMP. BMC Biol 2021; 19:227. [PMID: 34663304 PMCID: PMC8522238 DOI: 10.1186/s12915-021-01151-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 09/10/2021] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger that transduces extracellular signals in virtually all eukaryotic cells. The soluble Beggiatoa photoactivatable adenylyl cyclase (bPAC) rapidly raises cAMP in blue light and has been used to study cAMP signaling pathways cell-autonomously. But low activity in the dark might raise resting cAMP in cells expressing bPAC, and most eukaryotic cyclases are membrane-targeted rather than soluble. Our aim was to engineer a plasma membrane-anchored PAC with no dark activity (i.e., no cAMP accumulation in the dark) that rapidly increases cAMP when illuminated. RESULTS Using a streamlined method based on expression in Xenopus oocytes, we compared natural PACs and confirmed bPAC as the best starting point for protein engineering efforts. We identified several modifications that reduce bPAC dark activity. Mutating a phenylalanine to tyrosine at residue 198 substantially decreased dark cyclase activity, which increased 7000-fold when illuminated. Whereas Drosophila larvae expressing bPAC in mechanosensory neurons show nocifensive-like behavior even in the dark, larvae expressing improved soluble (e.g., bPAC(R278A)) and membrane-anchored PACs exhibited nocifensive responses only when illuminated. The plasma membrane-anchored PAC (PACmn) had an undetectable dark activity which increased >4000-fold in the light. PACmn does not raise resting cAMP nor, when expressed in hippocampal neurons, affect cAMP-dependent kinase (PKA) activity in the dark, but rapidly and reversibly increases cAMP and PKA activity in the soma and dendrites upon illumination. The peak responses to brief (2 s) light flashes exceed the responses to forskolin-induced activation of endogenous cyclases and return to baseline within seconds (cAMP) or ~10 min (PKA). CONCLUSIONS PACmn is a valuable optogenetic tool for precise cell-autonomous and transient stimulation of cAMP signaling pathways in diverse cell types.
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Affiliation(s)
- Shang Yang
- Department of Neurophysiology, Institute of Physiology, Biocenter, Julius-Maximilians-University of Würzburg, Röntgenring 9, 97070, Würzburg, Germany
| | - Oana M Constantin
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Divya Sachidanandan
- Department of Animal Physiology, Institute of Biology, Leipzig University, Talstraße 33, 04103, Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, Liebigstraße 27, 04103, Leipzig, Germany
| | - Hannes Hofmann
- Department of Animal Physiology, Institute of Biology, Leipzig University, Talstraße 33, 04103, Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, Liebigstraße 27, 04103, Leipzig, Germany
| | - Tobias C Kunz
- Department of Microbiology, Biocenter, Julius-Maximilians-University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Vera Kozjak-Pavlovic
- Department of Microbiology, Biocenter, Julius-Maximilians-University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Thomas G Oertner
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Georg Nagel
- Department of Neurophysiology, Institute of Physiology, Biocenter, Julius-Maximilians-University of Würzburg, Röntgenring 9, 97070, Würzburg, Germany
| | - Robert J Kittel
- Department of Animal Physiology, Institute of Biology, Leipzig University, Talstraße 33, 04103, Leipzig, Germany. .,Carl-Ludwig-Institute for Physiology, Leipzig University, Liebigstraße 27, 04103, Leipzig, Germany.
| | - Christine E Gee
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany.
| | - Shiqiang Gao
- Department of Neurophysiology, Institute of Physiology, Biocenter, Julius-Maximilians-University of Würzburg, Röntgenring 9, 97070, Würzburg, Germany.
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Vierock J, Rodriguez-Rozada S, Dieter A, Pieper F, Sims R, Tenedini F, Bergs ACF, Bendifallah I, Zhou F, Zeitzschel N, Ahlbeck J, Augustin S, Sauter K, Papagiakoumou E, Gottschalk A, Soba P, Emiliani V, Engel AK, Hegemann P, Wiegert JS. BiPOLES is an optogenetic tool developed for bidirectional dual-color control of neurons. Nat Commun 2021; 12:4527. [PMID: 34312384 PMCID: PMC8313717 DOI: 10.1038/s41467-021-24759-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 06/29/2021] [Indexed: 12/21/2022] Open
Abstract
Optogenetic manipulation of neuronal activity through excitatory and inhibitory opsins has become an indispensable experimental strategy in neuroscience research. For many applications bidirectional control of neuronal activity allowing both excitation and inhibition of the same neurons in a single experiment is desired. This requires low spectral overlap between the excitatory and inhibitory opsin, matched photocurrent amplitudes and a fixed expression ratio. Moreover, independent activation of two distinct neuronal populations with different optogenetic actuators is still challenging due to blue-light sensitivity of all opsins. Here we report BiPOLES, an optogenetic tool for potent neuronal excitation and inhibition with light of two different wavelengths. BiPOLES enables sensitive, reliable dual-color neuronal spiking and silencing with single- or two-photon excitation, optical tuning of the membrane voltage, and independent optogenetic control of two neuronal populations using a second, blue-light sensitive opsin. The utility of BiPOLES is demonstrated in worms, flies, mice and ferrets.
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Affiliation(s)
- Johannes Vierock
- Institute for Biology, Experimental Biophysics, Humboldt University Berlin, Berlin, Germany
| | - Silvia Rodriguez-Rozada
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Alexander Dieter
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Florian Pieper
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ruth Sims
- Wavefront-Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Federico Tenedini
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Amelie C F Bergs
- Buchmann Institute for Molecular Life Sciences and Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Imane Bendifallah
- Wavefront-Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Fangmin Zhou
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nadja Zeitzschel
- Buchmann Institute for Molecular Life Sciences and Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Joachim Ahlbeck
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sandra Augustin
- Institute for Biology, Experimental Biophysics, Humboldt University Berlin, Berlin, Germany
| | - Kathrin Sauter
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Eirini Papagiakoumou
- Wavefront-Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences and Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Peter Soba
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- LIMES Institute, University of Bonn, Bonn, Germany
| | - Valentina Emiliani
- Wavefront-Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Andreas K Engel
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Peter Hegemann
- Institute for Biology, Experimental Biophysics, Humboldt University Berlin, Berlin, Germany
| | - J Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Sarkar D, Harms H, Galleano I, Sheikh ZP, Pless SA. Ion channel engineering using protein trans-splicing. Methods Enzymol 2021; 654:19-48. [PMID: 34120713 DOI: 10.1016/bs.mie.2021.01.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Conventional site-directed mutagenesis and genetic code expansion approaches have been instrumental in providing detailed functional and pharmacological insight into membrane proteins such as ion channels. Recently, this has increasingly been complemented by semi-synthetic strategies, in which part of the protein is generated synthetically. This means a vast range of chemical modifications, including non-canonical amino acids (ncAA), backbone modifications, chemical handles, fluorescent or spectroscopic labels and any combination of these can be incorporated. Among these approaches, protein trans-splicing (PTS) is particularly promising for protein reconstitution in live cells. It relies on one or more split inteins, which can spontaneously and covalently link flanking peptide or protein sequences. Here, we describe the use of PTS and its variant tandem PTS (tPTS) in semi-synthesis of ion channels in Xenopus laevis oocytes to incorporate ncAAs, post-translational modifications or metabolically stable mimics thereof. This strategy has the potential to expand the type and number of modifications in ion channel research.
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Affiliation(s)
- Debayan Sarkar
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Hendrik Harms
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Iacopo Galleano
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Zeshan Pervez Sheikh
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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10
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Bansal H, Gupta N, Roy S. Theoretical Analysis of Low-power Bidirectional Optogenetic Control of High-frequency Neural Codes with Single Spike Resolution. Neuroscience 2020; 449:165-188. [DOI: 10.1016/j.neuroscience.2020.09.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 02/06/2023]
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11
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Richardson RT, Ibbotson MR, Thompson AC, Wise AK, Fallon JB. Optical stimulation of neural tissue. Healthc Technol Lett 2020; 7:58-65. [PMID: 32754339 PMCID: PMC7353819 DOI: 10.1049/htl.2019.0114] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/08/2020] [Accepted: 05/15/2020] [Indexed: 12/23/2022] Open
Abstract
Electrical stimulation has been used for decades in devices such as pacemakers, cochlear implants and more recently for deep brain and retinal stimulation and electroceutical treatment of disease. However, current spread from the electrodes limits the precision of neural activation, leading to a low quality therapeutic outcome or undesired side-effects. Alternative methods of neural stimulation such as optical stimulation offer the potential to deliver higher spatial resolution of neural activation. Direct optical stimulation is possible with infrared light, while visible light can be used to activate neurons if the neural tissue is genetically modified with a light sensitive ion channel. Experimentally, both methods have resulted in highly precise stimulation with little spread of activation at least in the cochlea, each with advantages and disadvantages. Infrared neural stimulation does not require modification of the neural tissue, but has very high power requirements. Optogenetics can achieve precision of activation with lower power, but only in conjunction with targeted insertion of a light sensitive ion channel into the nervous system via gene therapy. This review will examine the advantages and limitations of optical stimulation of neural tissue, using the cochlea as an exemplary model and recent developments for retinal and deep brain stimulation.
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Affiliation(s)
- Rachael Theresa Richardson
- Bionics Institute, Melbourne 3002, Australia.,University of Melbourne, Medical Bionics Department, Melbourne, 3002, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), Melbourne, 3002, Australia
| | - Michael R Ibbotson
- National Vision Research Institute, Australian College of Optometry, and Department of Optometry and Vision Science, University of Melbourne, Melbourne, Australia
| | | | - Andrew K Wise
- Bionics Institute, Melbourne 3002, Australia.,University of Melbourne, Medical Bionics Department, Melbourne, 3002, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), Melbourne, 3002, Australia
| | - James B Fallon
- Bionics Institute, Melbourne 3002, Australia.,University of Melbourne, Medical Bionics Department, Melbourne, 3002, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), Melbourne, 3002, Australia
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12
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Peng K, Liu S, Lv F, Fu X, Hussain S, Zhao H, Liu L, Wang S. Wireless Charging Electrochemiluminescence System for Ionic Channel Manipulation in Living Cells. ACS APPLIED MATERIALS & INTERFACES 2020; 12:24655-24661. [PMID: 32391678 DOI: 10.1021/acsami.0c07476] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Optogenetics holds great potential for precisely altering living cell behavior with the aid of light because of its high temporospatial resolution. However, the light-dependent manner severely limits its applications in deep tissues, particularly to those in the visible region. Here, we propose a wireless charging electrochemiluminescence (ECL) system, featured with long-time delayed luminescence, to remotely activate the light-gated ion channel (channelrhodopsin-2, ChR2) on the living cell membrane, followed by the intracellular influx of Ca2+ ions. Upon wireless charging ECL illumination, the influx of Ca2+ into the living cells triggers strong ion indicator fluorescence, suggesting the successful remote control on ChR2. As such, the wireless charging ECL strategy exhibits great potential to wireless control of optogenetics in deep tissues by implanting a device in vivo.
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Affiliation(s)
- Ke Peng
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100910, P. R. China
- College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Shanshan Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100910, P. R. China
| | - Fengting Lv
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100910, P. R. China
| | - Xuancheng Fu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100910, P. R. China
- College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Sameer Hussain
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100910, P. R. China
| | - Hao Zhao
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100910, P. R. China
- College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Libing Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100910, P. R. China
| | - Shu Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100910, P. R. China
- College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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13
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Walther F, Feind D, Vom Dahl C, Müller CE, Kukaj T, Sattler C, Nagel G, Gao S, Zimmer T. Action potentials in Xenopus oocytes triggered by blue light. J Gen Physiol 2020; 152:151581. [PMID: 32211871 PMCID: PMC7201882 DOI: 10.1085/jgp.201912489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 02/24/2020] [Indexed: 11/20/2022] Open
Abstract
Voltage-gated sodium (Na+) channels are responsible for the fast upstroke of the action potential of excitable cells. The different α subunits of Na+ channels respond to brief membrane depolarizations above a threshold level by undergoing conformational changes that result in the opening of the pore and a subsequent inward flux of Na+. Physiologically, these initial membrane depolarizations are caused by other ion channels that are activated by a variety of stimuli such as mechanical stretch, temperature changes, and various ligands. In the present study, we developed an optogenetic approach to activate Na+ channels and elicit action potentials in Xenopus laevis oocytes. All recordings were performed by the two-microelectrode technique. We first coupled channelrhodopsin-2 (ChR2), a light-sensitive ion channel of the green alga Chlamydomonas reinhardtii, to the auxiliary β1 subunit of voltage-gated Na+ channels. The resulting fusion construct, β1-ChR2, retained the ability to modulate Na+ channel kinetics and generate photosensitive inward currents. Stimulation of Xenopus oocytes coexpressing the skeletal muscle Na+ channel Nav1.4 and β1-ChR2 with 25-ms lasting blue-light pulses resulted in rapid alterations of the membrane potential strongly resembling typical action potentials of excitable cells. Blocking Nav1.4 with tetrodotoxin prevented the fast upstroke and the reversal of the membrane potential. Coexpression of the voltage-gated K+ channel Kv2.1 facilitated action potential repolarization considerably. Light-induced action potentials were also obtained by coexpressing β1-ChR2 with either the neuronal Na+ channel Nav1.2 or the cardiac-specific isoform Nav1.5. Potential applications of this novel optogenetic tool are discussed.
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Affiliation(s)
- Florian Walther
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Dominic Feind
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Christian Vom Dahl
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Christoph Emanuel Müller
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Taulant Kukaj
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Christian Sattler
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Georg Nagel
- Institute of Physiology-Neurophysiology, Biocentre, Julius-Maximilians-University, Wuerzburg, Germany
| | - Shiqiang Gao
- Institute of Physiology-Neurophysiology, Biocentre, Julius-Maximilians-University, Wuerzburg, Germany
| | - Thomas Zimmer
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
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Abstract
Over the past decade, basic sleep research investigating the circuitry controlling sleep and wakefulness has been boosted by pharmacosynthetic approaches, including chemogenetic techniques using designed receptors exclusively activated by designer drugs (DREADD). DREADD offers a series of tools that selectively control neuronal activity as a way to probe causal relationship between neuronal sub-populations and the regulation of the sleep-wake cycle. Following the path opened by optogenetics, DREADD tools applied to discrete neuronal sub-populations in numerous brain areas quickly made their contribution to the discovery and the expansion of our understanding of critical brain structures involved in a wide variety of behaviors and in the control of vigilance state architecture.
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15
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Feroz H, Ferlez B, Lefoulon C, Ren T, Baker CS, Gajewski JP, Lugar DJ, Gaudana SB, Butler PJ, Hühn J, Lamping M, Parak WJ, Hibberd JM, Kerfeld CA, Smirnoff N, Blatt MR, Golbeck JH, Kumar M. Light-Driven Chloride Transport Kinetics of Halorhodopsin. Biophys J 2019; 115:353-360. [PMID: 30021110 DOI: 10.1016/j.bpj.2018.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 05/19/2018] [Accepted: 06/05/2018] [Indexed: 01/25/2023] Open
Abstract
Despite growing interest in light-driven ion pumps for use in optogenetics, current estimates of their transport rates span two orders of magnitude due to challenges in measuring slow transport processes and determining protein concentration and/or orientation in membranes in vitro. In this study, we report, to our knowledge, the first direct quantitative measurement of light-driven Cl- transport rates of the anion pump halorohodopsin from Natronomonas pharaonis (NpHR). We used light-interfaced voltage clamp measurements on NpHR-expressing oocytes to obtain a transport rate of 219 (± 98) Cl-/protein/s for a photon flux of 630 photons/protein/s. The measurement is consistent with the literature-reported quantum efficiency of ∼30% for NpHR, i.e., 0.3 isomerizations per photon absorbed. To reconcile our measurements with an earlier-reported 20 ms rate-limiting step, or 35 turnovers/protein/s, we conducted, to our knowledge, novel consecutive single-turnover flash experiments that demonstrate that under continuous illumination, NpHR bypasses this step in the photocycle.
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Affiliation(s)
- Hasin Feroz
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania
| | - Bryan Ferlez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania
| | - Cecile Lefoulon
- Laboratory of Plant Physiology and Biophysics, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - Tingwei Ren
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania
| | - Carol S Baker
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania
| | - John P Gajewski
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania
| | - Daniel J Lugar
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania
| | - Sandeep B Gaudana
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Peter J Butler
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania
| | - Jonas Hühn
- Department of Physics and Chemistry, Philipps University of Marburg, Marburg, Germany
| | - Matthias Lamping
- Department of Physics and Chemistry, Philipps University of Marburg, Marburg, Germany
| | - Wolfgang J Parak
- Department of Physics and Chemistry, Philipps University of Marburg, Marburg, Germany
| | - Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Cheryl A Kerfeld
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan; Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, California; Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, California
| | | | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania
| | - Manish Kumar
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania.
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16
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Feroz H, Meisenhelter J, Jokhadze G, Bruening M, Kumar M. Rapid screening and scale‐up of ultracentrifugation‐free, membrane‐based procedures for purification of His‐tagged membrane proteins. Biotechnol Prog 2019; 35:e2859. [DOI: 10.1002/btpr.2859] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 04/13/2019] [Accepted: 05/03/2019] [Indexed: 12/28/2022]
Affiliation(s)
- Hasin Feroz
- Department of Chemical Engineering The Pennsylvania State University University Park Pennsylvania
| | - Joshua Meisenhelter
- Department of Chemical Engineering The Pennsylvania State University University Park Pennsylvania
| | | | - Merlin Bruening
- Department of Chemical and Biomolecular Engineering University of Notre Dame Notre Dame Indiana
| | - Manish Kumar
- Department of Chemical Engineering The Pennsylvania State University University Park Pennsylvania
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17
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Biró S, Lasztóczi B, Klausberger T. A Visual Two-Choice Rule-Switch Task for Head-Fixed Mice. Front Behav Neurosci 2019; 13:119. [PMID: 31244622 PMCID: PMC6562896 DOI: 10.3389/fnbeh.2019.00119] [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: 12/18/2018] [Accepted: 05/17/2019] [Indexed: 12/02/2022] Open
Abstract
Cognitive flexibility is the innate ability of the brain to change mental processes and to modify behavioral responses according to an ever-changing environment. As our brain has a limited capacity to process the information of our surroundings in any given moment, it uses sets as a strategy to aid neural processing systems. With assessing the capability of shifting between task sets, it is possible to test cognitive flexibility and executive functions. The most widely used neuropsychological task for the evaluation of these functions in humans is the Wisconsin Card Sorting Test (WCST), which requires the subject to alter response strategies and use previously irrelevant information to solve a problem. The test has proven clinical relevance, as poor performance has been reported in multiple neuropsychiatric conditions. Although, similar tasks have been used in pre-clinical rodent research, many are limited because of their manual-based testing procedures and their hardware attenuates neuronal recordings. We developed a two-choice rule-switch task whereby head-fixed C57BL/6 mice had to choose correctly one of the two virtual objects presented to retrieve a small water reward. The animals learnt to discriminate the visual cues and they successfully switched their strategies according to the related rules. We show that reaching successful performance after the rule changes required more trials in this task and that animals took more time to execute decisions when the two rules were in conflict. We used optogenetics to inhibit temporarily the medial prefrontal cortex (mPFC) during reward delivery and consumption, which significantly increased the number of trials needed to perform the second rule successfully (i.e., succeed in switching between rules), compared to control experiments. Furthermore, by assessing two types of error animals made after the rule switch, we show that interfering with the positive feedback integration, but leaving the negative feedback processing intact, does not influence the initial disengagement from the first rule, but impedes the maintenance of the newly acquired response set. These findings support the role of prefrontal networks in mice for cognitive flexibility, which is impaired during numerous neuropsychiatric diseases, such as schizophrenia and depression.
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Affiliation(s)
- Szabolcs Biró
- Center for Brain Research, Division of Cognitive Neurobiology, Medical University of Vienna, Vienna, Austria
| | - Bálint Lasztóczi
- Center for Brain Research, Division of Cognitive Neurobiology, Medical University of Vienna, Vienna, Austria
| | - Thomas Klausberger
- Center for Brain Research, Division of Cognitive Neurobiology, Medical University of Vienna, Vienna, Austria
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18
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Neubert F, Beliu G, Terpitz U, Werner C, Geis C, Sauer M, Doose S. Bioorthogonal Click Chemistry Enables Site-specific Fluorescence Labeling of Functional NMDA Receptors for Super-Resolution Imaging. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201808951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Franziska Neubert
- Department of Biotechnology and Biophysics; University of Würzburg; Biocenter; Am Hubland 97074 Würzburg Germany
| | - Gerti Beliu
- Department of Biotechnology and Biophysics; University of Würzburg; Biocenter; Am Hubland 97074 Würzburg Germany
| | - Ulrich Terpitz
- Department of Biotechnology and Biophysics; University of Würzburg; Biocenter; Am Hubland 97074 Würzburg Germany
| | - Christian Werner
- Department of Biotechnology and Biophysics; University of Würzburg; Biocenter; Am Hubland 97074 Würzburg Germany
| | - Christian Geis
- Hans-Berger Department of Neurology; Center for Sepsis Control and Care (CSCC); Jena University Hospital; Am Klinikum 1 07747 Jena Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics; University of Würzburg; Biocenter; Am Hubland 97074 Würzburg Germany
| | - Sören Doose
- Department of Biotechnology and Biophysics; University of Würzburg; Biocenter; Am Hubland 97074 Würzburg Germany
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19
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Neubert F, Beliu G, Terpitz U, Werner C, Geis C, Sauer M, Doose S. Bioorthogonal Click Chemistry Enables Site-specific Fluorescence Labeling of Functional NMDA Receptors for Super-Resolution Imaging. Angew Chem Int Ed Engl 2018; 57:16364-16369. [PMID: 30347512 DOI: 10.1002/anie.201808951] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/15/2018] [Indexed: 12/20/2022]
Abstract
Super-resolution microscopy requires small fluorescent labels. We report the application of genetic code expansion in combination with bioorthogonal click chemistry to label the NR1 domain of the NMDA receptor. We generated NR1 mutants incorporating an unnatural amino acid at various positions in order to attach small organic fluorophores such as Cy5-tetrazine site-specifically to the extracellular domain of the receptor. Mutants were optimized with regard to protein expression, labeling efficiency and receptor functionality as tested by fluorescence microscopy and whole-cell patch clamp. The results show that bioorthogonal click chemistry in combination with small organic dyes is superior to available immunocytochemistry protocols for receptor labeling in live and fixed cells and enables single-molecule sensitive super-resolution microscopy experiments.
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Affiliation(s)
- Franziska Neubert
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Gerti Beliu
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Ulrich Terpitz
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Christian Werner
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Christian Geis
- Hans-Berger Department of Neurology, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Sören Doose
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
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20
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Abstract
Optogenetics enables manipulation of biological processes with light at high spatio-temporal resolution to control the behavior of cells, networks, or even whole animals. In contrast to the performance of excitatory rhodopsins, the effectiveness of inhibitory optogenetic tools is still insufficient. Here we report a two-component optical silencer system comprising photoactivated adenylyl cyclases (PACs) and the small cyclic nucleotide-gated potassium channel SthK. Activation of this ‘PAC-K’ silencer by brief pulses of low-intensity blue light causes robust and reversible silencing of cardiomyocyte excitation and neuronal firing. In vivo expression of PAC-K in mouse and zebrafish neurons is well tolerated, where blue light inhibits neuronal activity and blocks motor responses. In combination with red-light absorbing channelrhodopsins, the distinct action spectra of PACs allow independent bimodal control of neuronal activity. PAC-K represents a reliable optogenetic silencer with intrinsic amplification for sustained potassium-mediated hyperpolarization, conferring high operational light sensitivity to the cells of interest. Optogenetic tools enable precise experimental control of the behaviour of cells. Here, the authors introduce a genetically-encoded two-protein system that enables silencing of excitable cells such as neurons and cardiomyocytes using blue light, and demonstrate its utility both in vitro and In vivo.
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21
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Luchkina NV, Bolshakov VY. Diminishing fear: Optogenetic approach toward understanding neural circuits of fear control. Pharmacol Biochem Behav 2018; 174:64-79. [PMID: 28502746 PMCID: PMC5681900 DOI: 10.1016/j.pbb.2017.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/13/2017] [Accepted: 05/10/2017] [Indexed: 02/05/2023]
Abstract
Understanding complex behavioral processes, both learned and innate, requires detailed characterization of the principles governing signal flow in corresponding neural circuits. Previous studies were hampered by the lack of appropriate tools needed to address the complexities of behavior-driving micro- and macrocircuits. The development and implementation of optogenetic methodologies revolutionized the field of behavioral neuroscience, allowing precise spatiotemporal control of specific, genetically defined neuronal populations and their functional connectivity both in vivo and ex vivo, thus providing unprecedented insights into the cellular and network-level mechanisms contributing to behavior. Here, we review recent pioneering advances in behavioral studies with optogenetic tools, focusing on mechanisms of fear-related behavioral processes with an emphasis on approaches which could be used to suppress fear when it is pathologically expressed. We also discuss limitations of these methodologies as well as review new technological developments which could be used in future mechanistic studies of fear behavior.
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Affiliation(s)
- Natalia V Luchkina
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
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22
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Kouyama T, Ihara K, Maki K, Chan SK. Three-Step Isomerization of the Retinal Chromophore during the Anion Pumping Cycle of Halorhodopsin. Biochemistry 2018; 57:6013-6026. [PMID: 30211543 DOI: 10.1021/acs.biochem.8b00631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The anion pumping cycle of halorhodopsin from Natronomonas pharaonis ( pHR) is initiated when the all- trans/15- anti isomer of retinal is photoisomerized into the 13- cis/15- anti configuration. A recent crystallographic study suggested that a reaction state with 13- cis/15- syn retinal occurred during the anion release process, i.e., after the N state with the 13- cis/15- anti retinal and before the O state with all- trans/15- anti retinal. In this study, we investigated the retinal isomeric composition in a long-living reaction state at various bromide ion concentrations. It was found that the 13- cis isomer (csHR'), in which the absorption spectrum was blue-shifted by ∼8 nm compared with that of the trans isomer (taHR), accumulated significantly when a cold suspension of pHR-rich claret membranes in 4 M NaBr was illuminated with continuous light. Analysis of flash-induced absorption changes suggested that the branching of the trans photocycle into the 13- cis isomer (csHR') occurs during the decay of an O-like state (O') with 13- cis/15- syn retinal; i.e., O' can decay to either csHR' or O with all- trans/15- anti retinal. The efficiency of the branching reaction was found to be dependent on the bromide ion concentration. At a very high bromide ion concentration, the anion pumping cycle is described by the scheme taHR -( hν) → K → L1a ↔ L1b ↔ N ↔ N' ↔ O' ↔ csHR' ↔ taHR. At a low bromide ion concentration, on the other hand, O' decays into taHR via O.
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Affiliation(s)
- Tsutomu Kouyama
- Department of Physics, Graduate School of Science , Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602 , Japan
| | - Kunio Ihara
- Center for Gene Research , Nagoya University , Nagoya 464-8602 , Japan
| | - Kosuke Maki
- Department of Physics, Graduate School of Science , Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602 , Japan
| | - Siu Kit Chan
- Department of Physics, Graduate School of Science , Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602 , Japan
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23
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Tu CH, Yi HP, Hsieh SY, Lin HS, Yang CS. Overexpression of Different Types of Microbial Rhodopsins with a Highly Expressible Bacteriorhodopsin from Haloarcula marismortui as a Single Protein in E. coli. Sci Rep 2018; 8:14026. [PMID: 30232361 PMCID: PMC6145879 DOI: 10.1038/s41598-018-32399-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 09/06/2018] [Indexed: 11/09/2022] Open
Abstract
Microbial rhodopsins (M-Rho) are found in Archaea, Bacteria and some species of Eukarya and serve as light-driven ion pumps or mediate phototaxis responses in various biological systems. We previously reported an expression system using a highly expressible mutant, D94N-HmBRI (HEBR) from Haloarcula marismortui, as a leading tag to assist in the expression of membrane proteins that were otherwise difficult to express in E. coli. In this study, we show a universal strategy for the expression of two M-Rho proteins, either the same or different types, as one fusion protein with the HEBR system. One extra transmembrane domain was engineered to the C-terminal of HEBR to express another target M-Rho. The average expression yield in this new system reached a minimum of 2 mg/L culture, and the maximum absorbance of the target M-Rho remained unaltered in the fusion forms. The fusion protein showed a combined absorbance spectrum of a lone HEBR and target M-Rho. The function of the target M-Rho was not affected after examination with functional tests, including the photocycle and proton pumping activity of fusion proteins. In addition, an otherwise unstable sensory rhodopsin, HmSRM, showed the same or even improved stability under various temperatures, salt concentrations, and a wide range of pH conditions. This HEBR platform provides the possibility to construct multi-functional, stoichiometric and color-tuning fusion proteins using M-Rho from haloarchaea.
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Affiliation(s)
- Cheng-Hong Tu
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10616, Taiwan
| | - Hsiu-Ping Yi
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10616, Taiwan
| | - Shiang-Yuan Hsieh
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10616, Taiwan
| | - Hong-Syuan Lin
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10616, Taiwan
| | - Chii-Shen Yang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10616, Taiwan.
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24
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Engelhard C, Chizhov I, Siebert F, Engelhard M. Microbial Halorhodopsins: Light-Driven Chloride Pumps. Chem Rev 2018; 118:10629-10645. [DOI: 10.1021/acs.chemrev.7b00715] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | - Igor Chizhov
- Institute for Biophysical Chemistry, Hannover Medical School, OE8830 Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Friedrich Siebert
- Institut für Molekulare Medizin und Zellforschung, Sektion Biophysik, Albert-Ludwigs-Universität Freiburg, Hermann-Herderstr. 9, 79104 Freiburg, Germany
| | - Martin Engelhard
- Max Planck Institute for Molecular Physiology, Otto Hahn Str. 11, 44227 Dortmund, Germany
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Norris JL, Hughes RM. protaTETHER - a method for the incorporation of variable linkers in protein fusions reveals impacts of linker flexibility in a PKAc-GFP fusion protein. FEBS Open Bio 2018; 8:1029-1042. [PMID: 29928581 PMCID: PMC5986021 DOI: 10.1002/2211-5463.12414] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/12/2018] [Accepted: 03/01/2018] [Indexed: 11/11/2022] Open
Abstract
Protein fusions are of fundamental importance in the study of cellular biology and the elucidation of cell signaling pathways, and the importance of linkers for the proper function of protein fusions is well documented in the literature. However, there are few convenient methods available to experimentalists for the systematic implementation of linkers in protein fusions. In this work, we describe a universal approach to the creation and insertion of focused linker libraries into protein fusions. This process, deemed protaTETHER, utilizes reiterative oligomer design, PCR-mediated linker library generation, and restriction enzyme-free cloning methods in a straightforward, three-step cloning process. We utilize a fusion between the catalytic subunit of cAMP-dependent protein kinase A (PKAc) and green fluorescent protein (GFP) for the development of the protaTETHER method, implementing small linker libraries that vary by length, sequence, and predicted secondary structural elements. We analyze the impact of linker length and sequence on the expression, activity, and subcellular localization of the PKAc-GFP fusions, and use these results to select a PKAc-GFP fusion construct with robust expression and enzymatic activity. Based upon the results of both biochemical experiments and molecular modeling, we determine that linker flexibility is more important than linker length for optimal kinase activity and expression.
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Streit J, Kleinlogel S. Dynamic all-optical drug screening on cardiac voltage-gated ion channels. Sci Rep 2018; 8:1153. [PMID: 29348631 PMCID: PMC5773578 DOI: 10.1038/s41598-018-19412-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/27/2017] [Indexed: 11/09/2022] Open
Abstract
Voltage-gated ion channels (VGCs) are prime targets for the pharmaceutical industry, but drug profiling on VGCs is challenging, since drug interactions are confined to specific conformational channel states mediated by changes in transmembrane potential. Here we combined various optogenetic tools to develop dynamic, high-throughput drug profiling assays with defined light-step protocols to interrogate VGC states on a millisecond timescale. We show that such light-induced electrophysiology (LiEp) yields high-quality pharmacological data with exceptional screening windows for drugs acting on the major cardiac VGCs, including hNav1.5, hKv1.5 and hERG. LiEp-based screening remained robust when using a variety of optogenetic actuators (ChR2, ChR2(H134R), CatCh, ChR2-EYFP-βArchT) and different types of organic (RH421, Di-4-ANBDQPQ, BeRST1) or genetic voltage sensors (QuasAr1). The tractability of LiEp allows a versatile and precise alternative to state-of-the-art VGC drug screening platforms such as automated electrophysiology or FLIPR readers.
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Affiliation(s)
- Jonas Streit
- Institute of Physiology, University of Bern, Bühlplatz 5, 3012, Bern, Switzerland
| | - Sonja Kleinlogel
- Institute of Physiology, University of Bern, Bühlplatz 5, 3012, Bern, Switzerland.
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27
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Chaffiol A, Caplette R, Jaillard C, Brazhnikova E, Desrosiers M, Dubus E, Duhamel L, Macé E, Marre O, Benoit P, Hantraye P, Bemelmans AP, Bamberg E, Duebel J, Sahel JA, Picaud S, Dalkara D. A New Promoter Allows Optogenetic Vision Restoration with Enhanced Sensitivity in Macaque Retina. Mol Ther 2017; 25:2546-2560. [PMID: 28807567 PMCID: PMC5675708 DOI: 10.1016/j.ymthe.2017.07.011] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 07/15/2017] [Accepted: 07/16/2017] [Indexed: 01/28/2023] Open
Abstract
The majority of inherited retinal degenerations converge on the phenotype of photoreceptor cell death. Second- and third-order neurons are spared in these diseases, making it possible to restore retinal light responses using optogenetics. Viral expression of channelrhodopsin in the third-order neurons under ubiquitous promoters was previously shown to restore visual function, albeit at light intensities above illumination safety thresholds. Here, we report (to our knowledge, for the first time) activation of macaque retinas, up to 6 months post-injection, using channelrhodopsin-Ca2+-permeable channelrhodopsin (CatCh) at safe light intensities. High-level CatCh expression was achieved due to a new promoter based on the regulatory region of the gamma-synuclein gene (SNCG) allowing strong expression in ganglion cells across species. Our promoter, in combination with clinically proven adeno-associated virus 2 (AAV2), provides CatCh expression in peri-foveolar ganglion cells responding robustly to light under the illumination safety thresholds for the human eye. On the contrary, the threshold of activation and the proportion of unresponsive cells were much higher when a ubiquitous promoter (cytomegalovirus [CMV]) was used to express CatCh. The results of our study suggest that the inclusion of optimized promoters is key in the path to clinical translation of optogenetics.
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Affiliation(s)
- Antoine Chaffiol
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France
| | - Romain Caplette
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France
| | - Céline Jaillard
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France
| | - Elena Brazhnikova
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France
| | - Mélissa Desrosiers
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France
| | - Elisabeth Dubus
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France
| | - Laëtitia Duhamel
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France
| | - Emilie Macé
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France
| | - Olivier Marre
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France
| | - Patrick Benoit
- Sanofi Ophthalmology Unit, 17 rue Moreau, 75012 Paris, France
| | - Philippe Hantraye
- Département des Sciences du Vivant (DSV), MIRCen, Institut d'Imagerie Biomédicale (I2BM), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses 92260, France; Neurodegenerative Diseases Laboratory, CNRS UMR9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses 92260, France
| | - Alexis-Pierre Bemelmans
- Département des Sciences du Vivant (DSV), MIRCen, Institut d'Imagerie Biomédicale (I2BM), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses 92260, France; Neurodegenerative Diseases Laboratory, CNRS UMR9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses 92260, France
| | - Ernst Bamberg
- Department of Biophysical Chemistry, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Jens Duebel
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France.
| | - José-Alain Sahel
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France; CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC, 28 rue de Charenton, 75012 Paris, France; Fondation Ophtalmologique Adolphe de Rothschild, 75019 Paris, France.
| | - Serge Picaud
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France.
| | - Deniz Dalkara
- INSERM U968, Institut de la Vision, 75012 Paris, France; UMRS968, Institut de la Vision, Sorbonne Universités, Pierre et Marie Curie University (UPMC) University Paris 06, 75012 Paris, France; Centre National de la Recherche Scientifique (CNRS) UMR7210, Institut de la Vision, 75012 Paris, France.
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28
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Shevchenko V, Mager T, Kovalev K, Polovinkin V, Alekseev A, Juettner J, Chizhov I, Bamann C, Vavourakis C, Ghai R, Gushchin I, Borshchevskiy V, Rogachev A, Melnikov I, Popov A, Balandin T, Rodriguez-Valera F, Manstein DJ, Bueldt G, Bamberg E, Gordeliy V. Inward H + pump xenorhodopsin: Mechanism and alternative optogenetic approach. SCIENCE ADVANCES 2017; 3:e1603187. [PMID: 28948217 PMCID: PMC5609834 DOI: 10.1126/sciadv.1603187] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 09/05/2017] [Indexed: 05/20/2023]
Abstract
Generation of an electrochemical proton gradient is the first step of cell bioenergetics. In prokaryotes, the gradient is created by outward membrane protein proton pumps. Inward plasma membrane native proton pumps are yet unknown. We describe comprehensive functional studies of the representatives of the yet noncharacterized xenorhodopsins from Nanohaloarchaea family of microbial rhodopsins. They are inward proton pumps as we demonstrate in model membrane systems, Escherichia coli cells, human embryonic kidney cells, neuroblastoma cells, and rat hippocampal neuronal cells. We also solved the structure of a xenorhodopsin from the nanohalosarchaeon Nanosalina (NsXeR) and suggest a mechanism of inward proton pumping. We demonstrate that the NsXeR is a powerful pump, which is able to elicit action potentials in rat hippocampal neuronal cells up to their maximal intrinsic firing frequency. Hence, inwardly directed proton pumps are suitable for light-induced remote control of neurons, and they are an alternative to the well-known cation-selective channelrhodopsins.
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Affiliation(s)
- Vitaly Shevchenko
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Jülich, Jülich, Germany
- Institute of Crystallography, RWTH Aachen University, Aachen, Germany
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Thomas Mager
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Kirill Kovalev
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Jülich, Jülich, Germany
- Institute of Crystallography, RWTH Aachen University, Aachen, Germany
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Vitaly Polovinkin
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Jülich, Jülich, Germany
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Institut de Biologie Structurale Jean-Pierre Ebel, Université Grenoble Alpes–Commissariat à l’Energie Atomique et aux Energies Alternatives–CNRS, Grenoble, France
| | - Alexey Alekseev
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Jülich, Jülich, Germany
- Institute of Crystallography, RWTH Aachen University, Aachen, Germany
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Josephine Juettner
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Igor Chizhov
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | | | - Charlotte Vavourakis
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Rohit Ghai
- Institute of Hydrobiology, Department of Aquatic Microbial Ecology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Ivan Gushchin
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Jülich, Jülich, Germany
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | | | - Andrey Rogachev
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Joint Institute for Nuclear Research, Dubna, Russia
| | - Igor Melnikov
- European Synchrotron Radiation Facility, 38027 Grenoble, France
| | - Alexander Popov
- European Synchrotron Radiation Facility, 38027 Grenoble, France
| | - Taras Balandin
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Jülich, Jülich, Germany
| | - Francisco Rodriguez-Valera
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Alicante, Spain
| | - Dietmar J. Manstein
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
- Division for Structural Biochemistry, Hannover Medical School, Hannover, Germany
| | - Georg Bueldt
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Valentin Gordeliy
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Jülich, Jülich, Germany
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Institut de Biologie Structurale Jean-Pierre Ebel, Université Grenoble Alpes–Commissariat à l’Energie Atomique et aux Energies Alternatives–CNRS, Grenoble, France
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29
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From Gene to Function: Cell-Free Electrophysiological and Optical Analysis of Ion Pumps in Nanodiscs. Biophys J 2017; 113:1331-1341. [PMID: 28450130 DOI: 10.1016/j.bpj.2017.03.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/14/2017] [Accepted: 03/27/2017] [Indexed: 12/15/2022] Open
Abstract
Nanodiscs that hold a lipid bilayer surrounded by a boundary of scaffold proteins have emerged as a powerful tool for membrane protein solubilization and analysis. By combining nanodiscs and cell-free expression technologies, even completely detergent-free membrane protein characterization protocols can be designed. Nanodiscs are compatible with various techniques, and due to their bilayer environment and increased stability, they are often superior to detergent micelles or liposomes for membrane protein solubilization. However, transport assays in nanodiscs have not been conducted so far, due to limitations of the two-dimensional nature of nanodisc membranes that offers no compartmentalization. Here, we study Krokinobacter eikastus rhodopsin-2 (KR2), a microbial light-driven sodium or proton pump, with noncovalent mass-spectrometric, electrophysiological, and flash photolysis measurements after its cotranslational insertion into nanodiscs. We demonstrate the feasibility of adsorbing nanodiscs containing KR2 to an artificial bilayer. This allows us to record light-induced capacitive currents that reflect KR2's ion transport activity. The solid-supported membrane assay with nanodisc samples provides reliable control over the ionic condition and information of the relative ion activity of this promiscuous pump. Our strategy is complemented with flash photolysis data, where the lifetimes of different photointermediates were determined at different ionic conditions. The advantage of using identical samples to three complementary approaches allows for a comprehensive comparability. The cell-free synthesis in combination with nanodiscs provides a defined hydrophobic lipid environment minimizing the detergent dependence often seen in assays with membrane proteins. KR2 is a promising tool for optogenetics, thus directed engineering to modify ion selectivity can be highly beneficial. Our approach, using the fast generation of functional ion pumps incorporated into nanodiscs and their subsequent analysis by several biophysical techniques, can serve as a versatile screening and engineering platform. This may open new avenues for the study of ion pumps and similar electrogenic targets.
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30
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Alfonsa H, Lakey JH, Lightowlers RN, Trevelyan AJ. Cl-out is a novel cooperative optogenetic tool for extruding chloride from neurons. Nat Commun 2016; 7:13495. [PMID: 27853135 PMCID: PMC5118542 DOI: 10.1038/ncomms13495] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 10/10/2016] [Indexed: 01/11/2023] Open
Abstract
Chloride regulation affects brain function in many ways, for instance, by dictating the GABAergic reversal potential, and thereby influencing neuronal excitability and spike timing. Consistent with this, there is increasing evidence implicating chloride in a range of neurological conditions. Investigations about these conditions, though, are made difficult by the limited range of tools available to manipulate chloride levels. In particular, there has been no way to actively remove chloride from neurons; we now describe an optogenetic strategy, ‘Cl-out', to do exactly this. Cl-out achieves its effect by the cooperative action of two different component opsins: the proton pump, Archaerhodopsin and a chloride channel opsin. The removal of chloride happens when both are activated together, using Archaerhodopsin as an optical voltage clamp to provide the driving force for chloride removal through the concurrently opened, chloride channels. We further show that this novel optogenetic strategy can reverse an in vitro epileptogenic phenotype. Chloride regulation is important for setting GABAergic reversal potential, though tools to manipulate chloride levels are limited. Here, the authors combine Archaerhodopsin with a chloride channel opsin to generate an optogenetic chloride extrusion strategy, ‘Cl-out', which they demonstrate in hippocampal slices.
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Affiliation(s)
- Hannah Alfonsa
- Institute of Neuroscience, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Jeremy H Lakey
- Institute for Cell and Molecular Biosciences, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Robert N Lightowlers
- Institute for Cell and Molecular Biosciences, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Andrew J Trevelyan
- Institute of Neuroscience, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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31
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Optochemokine Tandem for Light-Control of Intracellular Ca2. PLoS One 2016; 11:e0165344. [PMID: 27768773 PMCID: PMC5074463 DOI: 10.1371/journal.pone.0165344] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/10/2016] [Indexed: 01/13/2023] Open
Abstract
An optochemokine tandem was developed to control the release of calcium from endosomes into the cytosol by light and to analyze the internalization kinetics of G-protein coupled receptors (GPCRs) by electrophysiology. A previously constructed rhodopsin tandem was re-engineered to combine the light-gated Ca2+-permeable cation channel Channelrhodopsin-2(L132C), CatCh, with the chemokine receptor CXCR4 in a functional tandem protein tCXCR4/CatCh. The GPCR was used as a shuttle protein to displace CatCh from the plasma membrane into intracellular areas. As shown by patch-clamp measurements and confocal laser scanning microscopy, heterologously expressed tCXCR4/CatCh was internalized via the endocytic SDF1/CXCR4 signaling pathway. The kinetics of internalization could be followed electrophysiologically via the amplitude of the CatCh signal. The light-induced release of Ca2+ by tandem endosomes into the cytosol via CatCh was visualized using the Ca2+-sensitive dyes rhod2 and rhod2-AM showing an increase of intracellular Ca2+ in response to light.
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32
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Mechanism of Assembly and Cooperativity of Homomeric and Heteromeric Metabotropic Glutamate Receptors. Neuron 2016; 92:143-159. [PMID: 27641494 DOI: 10.1016/j.neuron.2016.08.036] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/19/2016] [Accepted: 08/19/2016] [Indexed: 11/23/2022]
Abstract
G protein-coupled receptors (GPCRs) mediate cellular responses to a wide variety of extracellular stimuli. GPCR dimerization may expand signaling diversity and tune functionality, but little is known about the mechanisms of subunit assembly and interaction or the signaling properties of heteromers. Using single-molecule subunit counting on class C metabotropic glutamate receptors (mGluRs), we map dimerization determinants and define a heterodimerization profile. Intersubunit fluorescence resonance energy transfer measurements reveal that interactions between ligand-binding domains control the conformational rearrangements underlying receptor activation. Selective liganding with photoswitchable tethered agonists conjugated to one or both subunits of covalently linked mGluR2 homodimers reveals that receptor activation is highly cooperative. Strikingly, this cooperativity is asymmetric in mGluR2/mGluR3 heterodimers. Our results lead to a model of cooperative activation of mGluRs that provides a framework for understanding how class C GPCRs couple extracellular binding to dimer reorganization and G protein activation.
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33
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Klapper SD, Swiersy A, Bamberg E, Busskamp V. Biophysical Properties of Optogenetic Tools and Their Application for Vision Restoration Approaches. Front Syst Neurosci 2016; 10:74. [PMID: 27642278 PMCID: PMC5009148 DOI: 10.3389/fnsys.2016.00074] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 08/17/2016] [Indexed: 11/13/2022] Open
Abstract
Optogenetics is the use of genetically encoded light-activated proteins to manipulate cells in a minimally invasive way using light. The most prominent example is channelrhodopsin-2 (ChR2), which allows the activation of electrically excitable cells via light-dependent depolarization. The combination of ChR2 with hyperpolarizing-light-driven ion pumps such as the Cl(-) pump halorhodopsin (NpHR) enables multimodal remote control of neuronal cells in culture, tissue, and living animals. Very soon, it became obvious that this method offers a chance of gene therapy for many diseases affecting vision. Here, we will give a brief introduction to retinal function and retinal diseases; optogenetic vision restoration strategies will be highlighted. We will discuss the functional and structural properties of rhodopsin-based optogenetic tools and analyze the potential for the application of vision restoration.
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Affiliation(s)
- Simon D Klapper
- Center for Regenerative Therapies Dresden, Technische Universität Dresden Dresden, Germany
| | - Anka Swiersy
- Center for Regenerative Therapies Dresden, Technische Universität Dresden Dresden, Germany
| | - Ernst Bamberg
- Max Planck Institute of Biophysics Frankfurt, Germany
| | - Volker Busskamp
- Center for Regenerative Therapies Dresden, Technische Universität Dresden Dresden, Germany
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34
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Ma SP, Vunjak-Novakovic G. Tissue-Engineering for the Study of Cardiac Biomechanics. J Biomech Eng 2016; 138:021010. [PMID: 26720588 PMCID: PMC4845250 DOI: 10.1115/1.4032355] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Indexed: 12/13/2022]
Abstract
The notion that both adaptive and maladaptive cardiac remodeling occurs in response to mechanical loading has informed recent progress in cardiac tissue engineering. Today, human cardiac tissues engineered in vitro offer complementary knowledge to that currently provided by animal models, with profound implications to personalized medicine. We review here recent advances in the understanding of the roles of mechanical signals in normal and pathological cardiac function, and their application in clinical translation of tissue engineering strategies to regenerative medicine and in vitro study of disease.
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Affiliation(s)
- Stephen P. Ma
- Department of Biomedical Engineering,
Columbia University,
622 West 168th Street,
VC12-234,
New York, NY 10032
e-mail:
| | - Gordana Vunjak-Novakovic
- Department of Biomedical Engineering
and Department of Medicine,
Columbia University,
622 West 168th Street,
VC12-234,
New York, NY 10032
e-mail:
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35
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Broadband activation by white-opsin lowers intensity threshold for cellular stimulation. Sci Rep 2015; 5:17857. [PMID: 26658483 PMCID: PMC4677322 DOI: 10.1038/srep17857] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 10/15/2015] [Indexed: 12/24/2022] Open
Abstract
Photoreceptors, which initiate the conversion of ambient light to action potentials via retinal circuitry, degenerate in retinal diseases such as retinitis pigmentosa and age related macular degeneration leading to loss of vision. Current prosthetic devices using arrays consisting of electrodes or LEDs (for optogenetic activation of conventional narrow-band opsins) have limited spatial resolution and can cause damage to retinal circuits by mechanical or photochemical (by absorption of intense narrow band light) means. Here, we describe a broad-band light activatable white-opsin for generating significant photocurrent at white light intensity levels close to ambient daylight conditions. White-opsin produced an order of magnitude higher photocurrent in response to white light as compared to narrow-band opsin channelrhodopsin-2, while maintaining the ms-channel kinetics. High fidelity of peak-photocurrent (both amplitude and latency) of white-opsin in response to repetitive white light stimulation of varying pulse width was observed. The significantly lower intensity stimulation required for activating white-opsin sensitized cells may facilitate ambient white light-based restoration of vision for patients with widespread photoreceptor degeneration.
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36
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Optogenetic acidification of synaptic vesicles and lysosomes. Nat Neurosci 2015; 18:1845-1852. [PMID: 26551543 PMCID: PMC4869830 DOI: 10.1038/nn.4161] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/08/2015] [Indexed: 12/12/2022]
Abstract
Acidification is required for the function of many intracellular organelles, but methods
to acutely manipulate their intraluminal pH have not been available. Here we
present a targeting strategy to selectively express the light-driven proton pump
Arch3 on synaptic vesicles. Our new tool, pHoenix, can functionally replace
endogenous proton pumps, enabling optogenetic control of vesicular acidification
and neurotransmitter accumulation. Under physiological conditions, glutamatergic
vesicles are nearly full, as additional vesicle acidification with pHoenix only
slightly increased the quantal size. By contrast, we found that incompletely
filled vesicles exhibited a lower release probability than full vesicles,
suggesting preferential exocytosis of vesicles with high transmitter content.
Our subcellular targeting approach can be transferred to other organelles, as
demonstrated for a pHoenix variant that allows light-activated acidification of
lysosomes.
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37
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Restoring the ON Switch in Blind Retinas: Opto-mGluR6, a Next-Generation, Cell-Tailored Optogenetic Tool. PLoS Biol 2015; 13:e1002143. [PMID: 25950461 PMCID: PMC4423780 DOI: 10.1371/journal.pbio.1002143] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 03/30/2015] [Indexed: 12/27/2022] Open
Abstract
Photoreceptor degeneration is one of the most prevalent causes of blindness. Despite photoreceptor loss, the inner retina and central visual pathways remain intact over an extended time period, which has led to creative optogenetic approaches to restore light sensitivity in the surviving inner retina. The major drawbacks of all optogenetic tools recently developed and tested in mouse models are their low light sensitivity and lack of physiological compatibility. Here we introduce a next-generation optogenetic tool, Opto-mGluR6, designed for retinal ON-bipolar cells, which overcomes these limitations. We show that Opto-mGluR6, a chimeric protein consisting of the intracellular domains of the ON-bipolar cell-specific metabotropic glutamate receptor mGluR6 and the light-sensing domains of melanopsin, reliably recovers vision at the retinal, cortical, and behavioral levels under moderate daylight illumination.
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38
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Jeschke M, Moser T. Considering optogenetic stimulation for cochlear implants. Hear Res 2015; 322:224-34. [PMID: 25601298 DOI: 10.1016/j.heares.2015.01.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 12/09/2014] [Accepted: 01/08/2015] [Indexed: 02/04/2023]
Abstract
Electrical cochlear implants are by far the most successful neuroprostheses and have been implanted in over 300,000 people worldwide. Cochlear implants enable open speech comprehension in most patients but are limited in providing music appreciation and speech understanding in noisy environments. This is generally considered to be due to low frequency resolution as a consequence of wide current spread from stimulation contacts. Accordingly, the number of independently usable stimulation channels is limited to less than a dozen. As light can be conveniently focused, optical stimulation might provide an alternative approach to cochlear implants with increased number of independent stimulation channels. Here, we focus on summarizing recent work on optogenetic stimulation as one way to develop optical cochlear implants. We conclude that proof of principle has been presented for optogenetic stimulation of the cochlea and central auditory neurons in rodents as well as for the technical realization of flexible μLED-based multichannel cochlear implants. Still, much remains to be done in order to advance the technique for auditory research and even more for eventual clinical translation. This article is part of a Special Issue entitled <Lasker Award>.
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Affiliation(s)
- Marcus Jeschke
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Goettingen, Germany; Auditory Neuroscience Group, German Primate Center, Goettingen, Germany.
| | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Goettingen, Germany; Auditory Neuroscience Group, German Primate Center, Goettingen, Germany; Bernstein Focus for Neurotechnology, University of Göttingen, Goettingen, Germany; Collaborative Research Center 889, University of Goettingen Medical Center, Goettingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Goettingen, Goettingen, Germany.
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39
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García-Martínez J, Brunk M, Avalos J, Terpitz U. The CarO rhodopsin of the fungus Fusarium fujikuroi is a light-driven proton pump that retards spore germination. Sci Rep 2015; 5:7798. [PMID: 25589426 PMCID: PMC4295100 DOI: 10.1038/srep07798] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 12/18/2014] [Indexed: 12/29/2022] Open
Abstract
Rhodopsins are membrane-embedded photoreceptors found in all major taxonomic kingdoms using retinal as their chromophore. They play well-known functions in different biological systems, but their roles in fungi remain unknown. The filamentous fungus Fusarium fujikuroi contains two putative rhodopsins, CarO and OpsA. The gene carO is light-regulated, and the predicted polypeptide contains all conserved residues required for proton pumping. We aimed to elucidate the expression and cellular location of the fungal rhodopsin CarO, its presumed proton-pumping activity and the possible effect of such function on F. fujikuroi growth. In electrophysiology experiments we confirmed that CarO is a green-light driven proton pump. Visualization of fluorescent CarO-YFP expressed in F. fujikuroi under control of its native promoter revealed higher accumulation in spores (conidia) produced by light-exposed mycelia. Germination analyses of conidia from carO(-) mutant and carO(+) control strains showed a faster development of light-exposed carO(-) germlings. In conclusion, CarO is an active proton pump, abundant in light-formed conidia, whose activity slows down early hyphal development under light. Interestingly, CarO-related rhodopsins are typically found in plant-associated fungi, where green light dominates the phyllosphere. Our data provide the first reliable clue on a possible biological role of a fungal rhodopsin.
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Affiliation(s)
- Jorge García-Martínez
- Department of Genetics, Faculty of Biology, University of Seville, E-41012 Seville, Spain
| | - Michael Brunk
- Department of Biotechnology and Biophysics, Biocenter, Julius Maximilian University Würzburg, D-97074 Würzburg, Germany
| | - Javier Avalos
- Department of Genetics, Faculty of Biology, University of Seville, E-41012 Seville, Spain
| | - Ulrich Terpitz
- Department of Biotechnology and Biophysics, Biocenter, Julius Maximilian University Würzburg, D-97074 Würzburg, Germany
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40
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Mutter M, Swietek N, Münch TA. Salvaging ruins: reverting blind retinas into functional visual sensors. Methods Mol Biol 2014; 1148:149-60. [PMID: 24718800 DOI: 10.1007/978-1-4939-0470-9_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Blindness is one of the most devastating conditions affecting the quality of life. Hereditary degenerative diseases, such as retinitis pigmentosa, are characterized by the progressive loss of photoreceptors, leading to complete blindness. No treatment is known, the current state-of-the-art of restoring vision are implanted electrode arrays. As a recently discovered alternative, optical neuromodulators, such as channelrhodopsin, allow new strategies for treating these diseases by imparting light-sensitivity onto the remaining retinal neurons after photoreceptor cell death. Retinal degeneration is a heterogeneous set of diseases with diverse secondary effects on the retinal circuitry. Successful treatment strategies have to take into account this diversity, as only the existing retinal hardware can serve as substrate for optogenetic intervention. The goal is to salvage the retinal ruins and to revert the leftover tissue into a functional visual sensor that operates as optimally as possible. Here, we discuss three different successful approaches that have been applied to degenerated mouse retina.
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Affiliation(s)
- Marion Mutter
- Centre for Integrative Neuroscience, Bernstein Center for Computational Biology, University Tübingen, Otfried-Müller-Str. 25, Tübingen, Germany
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41
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Amatrudo JM, Olson JP, Agarwal HK, Ellis-Davies GCR. Caged compounds for multichromic optical interrogation of neural systems. Eur J Neurosci 2014; 41:5-16. [PMID: 25471355 DOI: 10.1111/ejn.12785] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 10/06/2014] [Accepted: 10/13/2014] [Indexed: 01/16/2023]
Abstract
Caged compounds are widely used by neurophysiologists to study many aspects of cellular signaling in glia and neurons. Biologically inert before irradiation, they can be loaded into cells via patch pipette or topically applied in situ to a defined concentration; photolysis releases the caged compound in a very rapid and spatially defined way. As caged compounds are exogenous optical probes, they include not only natural products such neurotransmitters, calcium and IP3 but non-natural products such as fluorophores, drugs and antibodies. In this Technical Spotlight we provide a short introduction to the uncaging technique by discussing the nitroaromatic caging chromophores most widely used in such experiments [e.g. α-carboxy-ortho-nitrobenyl (CNB), dimethoxynitrobenzyl (DMNB), 4-methoxy-7-nitroindolinyl (MNI) and 4-carboxymethoxy-7-nitroindolinyl (CDNI)]. We show that recently developed caging chromophores [rutheniumbipyridial (RuBi) and 7-diethylaminocoumarin (DEAC)450] that are photolyzed with blue light (~ 430-480 nm range) can be combined with traditional nitroaromatic caged compounds to enable two-color optical probing of neuronal function. For example, one-photon uncaging of either RuBi-GABA or DEAC450-GABA with a 473-nm laser is facile, and can block nonlinear currents (dendritic spikes or action potentials) evoked by two-photon uncaging of CDNI-Glu at 720 nm. We also show that two-photon uncaging of DEAC450-Glu and CDNI-GABA at 900 and 720 nm, respectively, can be used to fire and block action potentials. Our experiments illustrate that recently developed chromophores have taken uncaging out of the 'monochrome era', in which it has existed since 1978, so as to enable multichromic interrogation of neuronal function with single-synapse precision.
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Affiliation(s)
- Joseph M Amatrudo
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, 10029, USA
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42
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Hochbaum DR, Zhao Y, Farhi SL, Klapoetke N, Werley CA, Kapoor V, Zou P, Kralj JM, Maclaurin D, Smedemark-Margulies N, Saulnier JL, Boulting GL, Straub C, Cho YK, Melkonian M, Wong GKS, Harrison DJ, Murthy VN, Sabatini BL, Boyden ES, Campbell RE, Cohen AE. All-optical electrophysiology in mammalian neurons using engineered microbial rhodopsins. Nat Methods 2014; 11:825-33. [PMID: 24952910 PMCID: PMC4117813 DOI: 10.1038/nmeth.3000] [Citation(s) in RCA: 505] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 05/17/2014] [Indexed: 01/27/2023]
Abstract
All-optical electrophysiology-spatially resolved simultaneous optical perturbation and measurement of membrane voltage-would open new vistas in neuroscience research. We evolved two archaerhodopsin-based voltage indicators, QuasAr1 and QuasAr2, which show improved brightness and voltage sensitivity, have microsecond response times and produce no photocurrent. We engineered a channelrhodopsin actuator, CheRiff, which shows high light sensitivity and rapid kinetics and is spectrally orthogonal to the QuasArs. A coexpression vector, Optopatch, enabled cross-talk-free genetically targeted all-optical electrophysiology. In cultured rat neurons, we combined Optopatch with patterned optical excitation to probe back-propagating action potentials (APs) in dendritic spines, synaptic transmission, subcellular microsecond-timescale details of AP propagation, and simultaneous firing of many neurons in a network. Optopatch measurements revealed homeostatic tuning of intrinsic excitability in human stem cell-derived neurons. In rat brain slices, Optopatch induced and reported APs and subthreshold events with high signal-to-noise ratios. The Optopatch platform enables high-throughput, spatially resolved electrophysiology without the use of conventional electrodes.
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Affiliation(s)
- Daniel R Hochbaum
- 1] Applied Physics Program, School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, USA. [2]
| | - Yongxin Zhao
- 1] Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada. [2]
| | - Samouil L Farhi
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Nathan Klapoetke
- 1] The MIT Media Laboratory, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA. [2] Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA. [3] Department of Brain and Cognitive Sciences, MIT, Cambridge, Massachusetts, USA. [4] McGovern Institute for Brain Research, MIT, Cambridge, Massachusetts, USA
| | - Christopher A Werley
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Vikrant Kapoor
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Peng Zou
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Joel M Kralj
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Dougal Maclaurin
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
| | | | - Jessica L Saulnier
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | | | - Christoph Straub
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Yong Ku Cho
- 1] The MIT Media Laboratory, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA. [2] Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA. [3] Department of Brain and Cognitive Sciences, MIT, Cambridge, Massachusetts, USA. [4] McGovern Institute for Brain Research, MIT, Cambridge, Massachusetts, USA
| | - Michael Melkonian
- Institute of Botany, Cologne Biocenter, University of Cologne, Cologne, Germany
| | - Gane Ka-Shu Wong
- 1] Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada. [2] Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. [3] Beijing Genomics Institute-Shenzhen, Shenzhen, China
| | - D Jed Harrison
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Venkatesh N Murthy
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Bernardo L Sabatini
- 1] Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA. [2] Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts, USA
| | - Edward S Boyden
- 1] The MIT Media Laboratory, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA. [2] Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA. [3] Department of Brain and Cognitive Sciences, MIT, Cambridge, Massachusetts, USA. [4] McGovern Institute for Brain Research, MIT, Cambridge, Massachusetts, USA. [5]
| | - Robert E Campbell
- 1] Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada. [2]
| | - Adam E Cohen
- 1] Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA. [2] Department of Physics, Harvard University, Cambridge, Massachusetts, USA. [3] Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts, USA
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43
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Ernst OP, Lodowski DT, Elstner M, Hegemann P, Brown L, Kandori H. Microbial and animal rhodopsins: structures, functions, and molecular mechanisms. Chem Rev 2014; 114:126-63. [PMID: 24364740 PMCID: PMC3979449 DOI: 10.1021/cr4003769] [Citation(s) in RCA: 771] [Impact Index Per Article: 77.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Indexed: 12/31/2022]
Affiliation(s)
- Oliver P. Ernst
- Departments
of Biochemistry and Molecular Genetics, University of Toronto, 1 King’s College Circle, Medical Sciences Building, Toronto, Ontario M5S 1A8, Canada
| | - David T. Lodowski
- Center
for Proteomics and Bioinformatics, Case
Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Marcus Elstner
- Institute
for Physical Chemistry, Karlsruhe Institute
of Technology, Kaiserstrasse
12, 76131 Karlsruhe, Germany
| | - Peter Hegemann
- Institute
of Biology, Experimental Biophysics, Humboldt-Universität
zu Berlin, Invalidenstrasse
42, 10115 Berlin, Germany
| | - Leonid
S. Brown
- Department
of Physics and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Hideki Kandori
- Department
of Frontier Materials, Nagoya Institute
of Technology, Showa-ku, Nagoya 466-8555, Japan
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44
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Abstract
Optogenetics is an emerging technology for the manipulation and control of excitable tissues, such as the brain and heart. As this technique requires the genetic modification of cells in order to inscribe light sensitivity, for cardiac applications, here we describe the process through which neonatal rat ventricular myocytes are virally infected in vitro with channelrhodopsin-2 (ChR2). We also describe in detail the procedure for quantitatively determining the optimal viral dosage, including instructions for patterning gene expression in multicellular cardiomyocyte preparations (cardiac syncytia) to simulate potential in vivo transgene distributions. Finally, we address optical actuation of ChR2-transduced cells and means to measure their functional response to light.
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45
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Strategies for expanding the operational range of channelrhodopsin in optogenetic vision. PLoS One 2013; 8:e81278. [PMID: 24312285 PMCID: PMC3842264 DOI: 10.1371/journal.pone.0081278] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 10/11/2013] [Indexed: 01/22/2023] Open
Abstract
Some hereditary diseases, such as retinitis pigmentosa, lead to blindness due to the death of photoreceptors, though the rest of the visual system might be only slightly affected. Optogenetics is a promising tool for restoring vision after retinal degeneration. In optogenetics, light-sensitive ion channels ("channelrhodopsins") are expressed in neurons so that the neurons can be activated by light. Currently existing variants of channelrhodopsin – engineered for use in neurophysiological research – do not necessarily support the goal of vision restoration optimally, due to two factors: First, the nature of the light stimulus is fundamentally different in "optogenetic vision" compared to "optogenetic neuroscience". Second, the retinal target neurons have specific properties that need to be accounted for, e.g. most retinal neurons are non-spiking. In this study, by using a computational model, we investigate properties of channelrhodopsin that might improve successful vision restoration. We pay particular attention to the operational brightness range and suggest strategies that would allow optogenetic vision over a wider intensity range than currently possible, spanning the brightest 5 orders of naturally occurring luminance. We also discuss the biophysical limitations of channelrhodopsin, and of the expressing cells, that prevent further expansion of this operational range, and we suggest design strategies for optogenetic tools which might help overcoming these limitations. Furthermore, the computational model used for this study is provided as an interactive tool for the research community.
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46
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Optical control of neuronal excitation and inhibition using a single opsin protein, ChR2. Sci Rep 2013; 3:3110. [PMID: 24173561 PMCID: PMC3813941 DOI: 10.1038/srep03110] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 10/14/2013] [Indexed: 12/11/2022] Open
Abstract
The effect of electrical stimulation on neuronal membrane potential is frequency dependent. Low frequency electrical stimulation can evoke action potentials, whereas high frequency stimulation can inhibit action potential transmission. Optical stimulation of channelrhodopsin-2 (ChR2) expressed in neuronal membranes can also excite action potentials. However, it is unknown whether optical stimulation of ChR2-expressing neurons produces a transition from excitation to inhibition with increasing light pulse frequencies. Here we report optical inhibition of motor neuron and muscle activity in vivo in the cooled sciatic nerves of Thy1-ChR2-EYFP mice. We also demonstrate all-optical single-wavelength control of neuronal excitation and inhibition without co-expression of inhibitory and excitatory opsins. This all-optical system is free from stimulation-induced electrical artifacts and thus provides a new approach to investigate mechanisms of high frequency inhibition in neuronal circuits in vivo and in vitro.
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47
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Bamann C, Bamberg E, Wachtveitl J, Glaubitz C. Proteorhodopsin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:614-25. [PMID: 24060527 DOI: 10.1016/j.bbabio.2013.09.010] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/11/2013] [Accepted: 09/13/2013] [Indexed: 10/26/2022]
Abstract
Proteorhodopsins are the most abundant retinal based photoreceptors and their phototrophic function might be relevant in marine ecosystems. Here, we describe their remarkable molecular properties with a special focus on the green absorbing variant. Its distinct features include a high pKa value of the primary proton acceptor stabilized through an interaction with a conserved histidine, a long-range interaction between the cytoplasmic EF loop and the chromophore entailing a particular mode of color tuning and a variable proton pumping vectoriality with complex voltage-dependence. The proteorhodopsin family represents a profound example for structure-function relationships. Especially the development of a biophysical understanding of green proteorhodopsin is an excellent example for the unique opportunities offered by a combined approach of advanced spectroscopic and electrophysiological methods. This article is part of a Special Issue entitled: Retinal Proteins-You can teach an old dog new tricks.
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Affiliation(s)
- Christian Bamann
- Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438 Frankfurt am Main, Germany.
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438 Frankfurt am Main, Germany
| | - Josef Wachtveitl
- Johann Wolfgang Goethe University, Institute for Physical and Theoretical Chemistry, Max-von-Laue Straße 7, 60438 Frankfurt am Main, Germany
| | - Clemens Glaubitz
- Johann Wolfgang Goethe University, Institute for Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
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48
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Govorunova EG, Sineshchekov OA, Li H, Janz R, Spudich JL. Characterization of a highly efficient blue-shifted channelrhodopsin from the marine alga Platymonas subcordiformis. J Biol Chem 2013; 288:29911-22. [PMID: 23995841 DOI: 10.1074/jbc.m113.505495] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Rhodopsin photosensors of phototactic algae act as light-gated cation channels when expressed in animal cells. These proteins (channelrhodopsins) are extensively used for millisecond scale photocontrol of cellular functions (optogenetics). We report characterization of PsChR, one of the phototaxis receptors in the alga Platymonas (Tetraselmis) subcordiformis. PsChR exhibited ∼3-fold higher unitary conductance and greater relative permeability for Na(+) ions, as compared with the most frequently used channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2). Photocurrents generated by PsChR in HEK293 cells showed lesser inactivation and faster peak recovery than those by CrChR2. Their maximal spectral sensitivity was at 445 nm, making PsChR the most blue-shifted channelrhodopsin so far identified. The λmax of detergent-purified PsChR was 437 nm at neutral pH and exhibited red shifts (pKa values at 6.6 and 3.8) upon acidification. The purified pigment undergoes a photocycle with a prominent red-shifted intermediate whose formation and decay kinetics match the kinetics of channel opening and closing. The rise and decay of an M-like intermediate prior to formation of this putative conductive state were faster than in CrChR2. PsChR mediated sufficient light-induced membrane depolarization in cultured hippocampal neurons to trigger reliable repetitive spiking at the upper threshold frequency of the neurons. At low frequencies spiking probability decreases less with PsChR than with CrChR2 because of the faster recovery of the former. Its blue-shifted absorption enables optogenetics at wavelengths even below 400 nm. A combination of characteristics makes PsChR important for further research on structure-function relationships in ChRs and potentially useful for optogenetics, especially for combinatorial applications when short wavelength excitation is required.
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Affiliation(s)
- Elena G Govorunova
- From the Department of Biochemistry & Molecular Biology, Center for Membrane Biology and
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49
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Packer AM, Roska B, Häusser M. Targeting neurons and photons for optogenetics. Nat Neurosci 2013; 16:805-15. [PMID: 23799473 PMCID: PMC4928704 DOI: 10.1038/nn.3427] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 05/10/2013] [Indexed: 12/11/2022]
Abstract
Optogenetic approaches promise to revolutionize neuroscience by using light to manipulate neural activity in genetically or functionally defined neurons with millisecond precision. Harnessing the full potential of optogenetic tools, however, requires light to be targeted to the right neurons at the right time. Here we discuss some barriers and potential solutions to this problem. We review methods for targeting the expression of light-activatable molecules to specific cell types, under genetic, viral or activity-dependent control. Next we explore new ways to target light to individual neurons to allow their precise activation and inactivation. These techniques provide a precision in the temporal and spatial activation of neurons that was not achievable in previous experiments. In combination with simultaneous recording and imaging techniques, these strategies will allow us to mimic the natural activity patterns of neurons in vivo, enabling previously impossible 'dream experiments'.
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Affiliation(s)
- Adam M. Packer
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Botond Roska
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Michael Häusser
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
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50
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Abstract
Sight-restoring therapy for the visually impaired and blind is a major unmet medical need. Ocular gene therapy is a rational choice for restoring vision or preventing the loss of vision because most blinding diseases originate in cellular components of the eye, a compartment that is optimally suited for the delivery of genes, and many of these diseases have a genetic origin or genetic component. In recent years we have witnessed major advances in the field of ocular gene therapy, and proof-of-concept studies are under way to evaluate the safety and efficacy of human gene therapies. Here we discuss the concepts and recent advances in gene therapy in the retina. Our review discusses traditional approaches such as gene replacement and neuroprotection and also new avenues such as optogenetic therapies. We conjecture that advances in gene therapy in the retina will pave the way for gene therapies in other parts of the brain.
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Affiliation(s)
- José-Alain Sahel
- INSERM UMR_S 968, UPMC, University of Paris 06, Institut de la Vision, Paris, France.
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