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Vafadari B, Tacke C, Harb A, Grützner AA, Hülsmann S. Increase of breathing rate mediated by unilateral optogenetic inactivation of inhibitory neurons in the preBötzinger Complex in vivo. Respir Physiol Neurobiol 2023; 311:104032. [PMID: 36758781 DOI: 10.1016/j.resp.2023.104032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/26/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023]
Abstract
Brainstem neural circuits located in the preBötzinger complex (preBötC) and Bötzinger complex (BötC) play a critical role in the control of breathing. In this study, glycinergic preBötC and BötC neurons were inactivated with optogenetics in vivo using mice with Cre inducible expression of eNpHR3.0-EYFP. Unilateral inhibition of glycinergic neurons in the preBötC, and to a lower extend also in the BötC, led to a higher respiratory rate. It can be concluded that functional inactivation of inhibitory neurons leads to a disinhibition of preBötC excitatory neurons and thus an increase in the respiratory drive of the network.
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Affiliation(s)
- Behnam Vafadari
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany.
| | - Charlotte Tacke
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Ali Harb
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Anja-Annett Grützner
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Swen Hülsmann
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany.
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2
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Flores-Dourojeanni JP, van den Munkhof MH, Luijendijk MCM, Vanderschuren LJMJ, Adan RAH. Inhibition of ventral tegmental area projections to the nucleus accumbens shell increases premature responding in the five-choice serial reaction time task in rats. Brain Struct Funct 2023; 228:787-798. [PMID: 36843155 PMCID: PMC10147763 DOI: 10.1007/s00429-023-02618-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2023] [Indexed: 02/28/2023]
Abstract
Exaggerated impulsivity and attentional impairments are hallmarks of certain disorders of behavioural control such as attention-deficit/hyperactivity disorder (ADHD), schizophrenia and addiction. Pharmacological studies have implicated elevated dopamine (DA) levels in the nucleus accumbens shell (NAcbS) in impulsive actions. The NAcbS receives its DA input from the ventral tegmental area (VTA), and we have previously shown that optogenetic activation of VTA-NAcbS projections impaired impulse control and attention in the five-choice serial reaction time task (5-CSRTT) in rats. To better understand the role of VTA-NAcbS projections in impulsivity and attention, the present study sought to inhibit this projection using optogenetics. We demonstrate that inhibiting VTA-NAcbS efferents during the last seconds of the inter-trial interval (i.e. immediately before presentation of the instructive cue) induces exaggerated impulsive action, in the absence of changes in attentional or motivational parameters in the 5-CSRTT. Together with our earlier observations, this suggests that impulse control in the 5-CSRTT is tightly controlled by VTA-NAcbS activity, with deviations in both directions resulting in increased impulsivity.
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Affiliation(s)
- Jacques P Flores-Dourojeanni
- Department of Translational Neuroscience, Brain Center, University Medical Center Utrecht, 3508, GA, Utrecht, The Netherlands.,Department of Population Health Sciences, Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, 3584, CM, Utrecht, The Netherlands
| | - Marleen H van den Munkhof
- Department of Translational Neuroscience, Brain Center, University Medical Center Utrecht, 3508, GA, Utrecht, The Netherlands
| | - Mieneke C M Luijendijk
- Department of Translational Neuroscience, Brain Center, University Medical Center Utrecht, 3508, GA, Utrecht, The Netherlands
| | - Louk J M J Vanderschuren
- Department of Population Health Sciences, Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, 3584, CM, Utrecht, The Netherlands
| | - Roger A H Adan
- Department of Translational Neuroscience, Brain Center, University Medical Center Utrecht, 3508, GA, Utrecht, The Netherlands. .,Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, 405 30, Gothenburg, Sweden.
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Selvaraj MK, Thakur A, Kumar M, Pinnaka AK, Suri CR, Siddhardha B, Elumalai SP. Ion-pumping microbial rhodopsin protein classification by machine learning approach. BMC Bioinformatics 2023; 24:29. [PMID: 36707759 PMCID: PMC9881276 DOI: 10.1186/s12859-023-05138-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 01/04/2023] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Rhodopsin is a seven-transmembrane protein covalently linked with retinal chromophore that absorbs photons for energy conversion and intracellular signaling in eukaryotes, bacteria, and archaea. Haloarchaeal rhodopsins are Type-I microbial rhodopsin that elicits various light-driven functions like proton pumping, chloride pumping and Phototaxis behaviour. The industrial application of Ion-pumping Haloarchaeal rhodopsins is limited by the lack of full-length rhodopsin sequence-based classifications, which play an important role in Ion-pumping activity. The well-studied Haloarchaeal rhodopsin is a proton-pumping bacteriorhodopsin that shows promising applications in optogenetics, biosensitized solar cells, security ink, data storage, artificial retinal implant and biohydrogen generation. As a result, a low-cost computational approach is required to identify Ion-pumping Haloarchaeal rhodopsin sequences and its subtype. RESULTS This study uses a support vector machine (SVM) technique to identify these ion-pumping Haloarchaeal rhodopsin proteins. The haloarchaeal ion pumping rhodopsins viz., bacteriorhodopsin, halorhodopsin, xanthorhodopsin, sensoryrhodopsin and marine prokaryotic Ion-pumping rhodopsins like actinorhodopsin, proteorhodopsin have been utilized to develop the methods that accurately identified the ion pumping haloarchaeal and other type I microbial rhodopsins. We achieved overall maximum accuracy of 97.78%, 97.84% and 97.60%, respectively, for amino acid composition, dipeptide composition and hybrid approach on tenfold cross validation using SVM. Predictive models for each class of rhodopsin performed equally well on an independent data set. In addition to this, similar results were achieved using another machine learning technique namely random forest. Simultaneously predictive models performed equally well during five-fold cross validation. Apart from this study, we also tested the own, blank, BLAST dataset and annotated whole-genome rhodopsin sequences of PWS haloarchaeal isolates in the developed methods. The developed web server ( https://bioinfo.imtech.res.in/servers/rhodopred ) can identify the Ion Pumping Haloarchaeal rhodopsin proteins and their subtypes. We expect this web tool would be useful for rhodopsin researchers. CONCLUSION The overall performance of the developed method results show that it accurately identifies the Ionpumping Haloarchaeal rhodopsin and their subtypes using known and unknown microbial rhodopsin sequences. We expect that this study would be useful for optogenetics, molecular biologists and rhodopsin researchers.
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Affiliation(s)
- Muthu Krishnan Selvaraj
- grid.418099.dMTCC-Microbial Type Culture Collection and Gene Bank, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Anamika Thakur
- grid.418099.dVirology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Manoj Kumar
- grid.418099.dVirology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Anil Kumar Pinnaka
- grid.418099.dMTCC-Microbial Type Culture Collection and Gene Bank, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Chander Raman Suri
- grid.418099.dBiosensor Department, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Busi Siddhardha
- grid.412517.40000 0001 2152 9956Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, 605014 India
| | - Senthil Prasad Elumalai
- grid.418099.dBiochemical Engineering Research and Process Development Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
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Stern MA, Skelton H, Fernandez AM, Gutekunst CAN, Berglund K, Gross RE. Bioluminescence-Optogenetics: A Practical Guide. Methods Mol Biol 2022; 2525:333-346. [PMID: 35836081 DOI: 10.1007/978-1-0716-2473-9_26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Manipulation of neural activity in genetically predefined populations of neurons through genetic techniques is an essential tool in the field of neuroscience as well as a potential avenue in treating a vast assortment of neurological and psychiatric diseases. Here, we describe an emerging methodology of molecular neuromodulation termed bioluminescence-optogenetics (BL-OG) where BL is harnessed to activate bacterial light-driven channels and pumps expressed in neurons to control their activity. BL-OG is realized through opsin-luciferase fusion proteins called luminopsins (LMOs). In this chapter, we will provide a practical guide for applying BL-OG and LMOs in vitro using a cell line and primary cells in culture. In the following chapter, we will turn our focus towards BL-OG applications in ex vivo and in vivo rodent models of the nervous system.
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Affiliation(s)
- Matthew A Stern
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Henry Skelton
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | | | | | - Ken Berglund
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA.
| | - Robert E Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
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Bergs A, Henss T, Glock C, Nagpal J, Gottschalk A. Microbial Rhodopsin Optogenetic Tools: Application for Analyses of Synaptic Transmission and of Neuronal Network Activity in Behavior. Methods Mol Biol 2022; 2468:89-115. [PMID: 35320562 DOI: 10.1007/978-1-0716-2181-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Over the past 15 years, optogenetic methods have revolutionized neuroscientific and cell biological research, also in the nematode Caenorhabditis elegans. In this chapter, we give an update about current optogenetic tools and methods to address neuronal activity and inhibition, as well as second messenger signaling, based on microbial rhodopsins. We address channelrhodopsins and variants thereof, which conduct cations or anions, for depolarization and hyperpolarization of the membrane potential. Also, we cover ion pumping rhodopsins, like halorhodopsin, Mac, and Arch. A recent addition to rhodopsin-based optogenetics is voltage imaging tools that allow fluorescent readout of membrane voltage (directly, via fluorescence of the rhodopsin chromophore retinal, or indirectly, via electrochromic FRET). Last, we report on a new addition to the optogenetic toolbox, which is rhodopsin guanylyl cyclases, as well as mutated variants with specificity for cyclic AMP. These can be used to regulate intracellular levels of cGMP and cAMP, which are important second messengers in sensory and other neurons. We further show how they can be combined with cyclic nucleotide-gated channels in two-component optogenetics, for depolarization or hyperpolarization of membrane potential. For all tools, we present protocols for straightforward experimentation to address neuronal activation and inhibition, particularly at the neuromuscular junction, and for combined optogenetic actuation and Ca2+ imaging. We also provide protocols for usage of rhodopsin guanylyl and adenylyl cyclases. Finally, we list a number of points to consider when designing and conducting rhodopsin-based optogenetic experiments.
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Affiliation(s)
- Amelie Bergs
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Thilo Henss
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Caspar Glock
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
- Max-Planck-Institute for Brain Research, Frankfurt, Germany
| | - Jatin Nagpal
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany.
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Abstract
Epilepsy is the fourth most common neurological disorder, but current treatment options provide limited efficacy and carry the potential for problematic adverse effects. There is an immense need to develop new therapeutic interventions in epilepsy, and targeting areas outside the seizure focus for neuromodulation has shown therapeutic value. While not traditionally associated with epilepsy, anatomical, clinical, and electrophysiological studies suggest the cerebellum can play a role in seizure networks, and importantly, may be a potential therapeutic target for seizure control. However, previous interventions targeting the cerebellum in both preclinical and clinical studies have produced mixed effects on seizures. These inconsistent results may be due in part to the lack of specificity inherent with open-loop electrical stimulation interventions. More recent studies, using more targeted closed-loop optogenetic approaches, suggest the possibility of robust seizure inhibition via cerebellar modulation for a range of seizure types. Therefore, while the mechanisms of cerebellar inhibition of seizures have yet to be fully elucidated, the cerebellum should be thoroughly revisited as a potential target for therapeutic intervention in epilepsy. This article is part of the Special Issue "NEWroscience 2018.
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Feroz H, Ferlez B, Oh H, Mohammadiarani H, Ren T, Baker CS, Gajewski JP, Lugar DJ, Gaudana SB, Butler P, Hühn J, Lamping M, Parak WJ, Blatt MR, Kerfeld CA, Smirnoff N, Vashisth H, Golbeck JH, Kumar M. Liposome-based measurement of light-driven chloride transport kinetics of halorhodopsin. Biochim Biophys Acta Biomembr 2021; 1863:183637. [PMID: 33930372 DOI: 10.1016/j.bbamem.2021.183637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 04/14/2021] [Accepted: 04/22/2021] [Indexed: 11/30/2022]
Abstract
We report a simple and direct fluorimetric vesicle-based method for measuring the transport rate of the light-driven ions pumps as specifically applied to the chloride pump, halorhodopsin, from Natronomonas pharaonis (pHR). Previous measurements were cell-based and methods to determine average single channel permeability challenging. We used a water-in-oil emulsion method for directional pHR reconstitution into two different types of vesicles: lipid vesicles and asymmetric lipid-block copolymer vesicles. We then used stopped-flow experiments combined with fluorescence correlation spectroscopy to determine per protein Cl- transport rates. We obtained a Cl- transport rate of 442 (±17.7) Cl-/protein/s in egg phosphatidyl choline (PC) lipid vesicles and 413 (±26) Cl-/protein/s in hybrid block copolymer/lipid (BCP/PC) vesicles with polybutadine-polyethylene oxide (PB12PEO8) on the outer leaflet and PC in the inner leaflet at a photon flux of 1450 photons/protein/s. Normalizing to a per photon basis, this corresponds to 0.30 (±0.07) Cl-/photon and 0.28 (±0.04) Cl-/photon for pure PC and BCP/PC hybrid vesicles respectively, both of which are in agreement with recently reported turnover of ~500 Cl-/protein/s from flash photolysis experiments and with voltage-clamp measurements of 0.35 (±0.16) Cl-/photon in pHR-expressing oocytes as well as with a pHR quantum efficiency of ~30%.
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Affiliation(s)
- Hasin Feroz
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Bryan Ferlez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Hyeonji Oh
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | | | - Tingwei Ren
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Carol S Baker
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - John P Gajewski
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Daniel J Lugar
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Sandeep B Gaudana
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Peter Butler
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - 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
- Center of Hybrid Nanostructures (CHyN), Universität Hamburg, Hamburg, Germany
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, Institute of Molecular Cell and Systems Biology, Bower Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Cheryl A Kerfeld
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA; Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA; Environmental Genomics and Systems Biology and Molecular Biophysics and Integrated Bioimaging Divisions, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Harish Vashisth
- Department of Chemical Engineering, The University of New Hampshire, Durham, NH, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA; Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Manish Kumar
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, TX, USA.
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Berglund K, Stern MA, Gross RE. Bioluminescence-Optogenetics. Adv Exp Med Biol 2021; 1293:281-293. [PMID: 33398820 DOI: 10.1007/978-981-15-8763-4_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
In this chapter, we introduce a relatively new, emerging method for molecular neuromodulation-bioluminescence-optogenetics. Bioluminescence-optogenetics is mediated by luminopsin fusion proteins-light-sensing opsins fused to light-emitting luciferases. We describe their structures and working mechanisms and discuss their unique benefits over conventional optogenetics and chemogenetics. We also summarize applications of bioluminescence-optogenetics in various neurological disease models in rodents.
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Affiliation(s)
- Ken Berglund
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA.
| | - Matthew A Stern
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
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Abstract
Cl--pump rhodopsin is the second discovered microbial rhodopsin. Although its physiological role has not been fully clarified, its functional mechanism has been studied as a model for anion transporters. After the success of neural activation by channel rhodopsin, the first Cl--pump halorhodopsin (HR) had become widely used as a neural silencer. The emergence of artificial and natural anion channel rhodopsins lowered the importance of HRs. However, the longer absorption maxima of approximately 585-600 nm for HRs are still advantageous for applications in mammalian brains and collaborations with neural activators possessing shorter absorption maxima. In this chapter, the variation and functional mechanisms of Cl- pumps are summarized. After the discovery of HR, Cl--pump rhodopsins were confined to only extremely halophilic haloarchaea. However, after 2014, two Cl--pump groups were newly discovered in marine and terrestrial bacteria. These Cl- pumps are phylogenetically distinct from HRs and have unique characteristics. In particular, the most recently identified Cl- pump has close similarity with the H+ pump bacteriorhodopsin and was converted into the H+ pump by a single amino acid replacement.
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10
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Ivanova E, Corona C, Eleftheriou CG, Bianchimano P, Sagdullaev BT. Retina-specific targeting of pericytes reveals structural diversity and enables control of capillary blood flow. J Comp Neurol 2020; 529:1121-1134. [PMID: 32812219 DOI: 10.1002/cne.25011] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 12/14/2022]
Abstract
Pericytes are a unique class of mural cells essential for angiogenesis, maintenance of the vasculature and are key players in microvascular pathology. However, their diversity and specific roles are poorly understood, limiting our insight into vascular physiology and the ability to develop effective therapies. Here, in the mouse retina, a tractable model of the CNS, we evaluated distinct classes of mural cells along the vascular tree for both structural characterization and physiological manipulation of blood flow. To accomplish this, we first tested three inducible mural cell-specific mouse lines using a sensitive Ai14 reporter and tamoxifen application either by a systemic injection, or by local administration in the form of eye drops. The specificity and pattern of cre activation varied significantly across the three lines, under either the PDGFRβ or NG2 promoter (Pdgfrβ-CreRha, Pdgfrβ-CreCsln, and Cspg4-Cre). In particular, a mouse line with Cre under the NG2 promoter resulted in sparse TdTomato labeling of mural cells, allowing for an unambiguous characterization of anatomical features of individual sphincter cells and capillary pericytes. Furthermore, in one PDGFRβ line, we found that focal eye drop application of tamoxifen led to an exclusive Cre-activation in pericytes, without affecting arterial mural cells. We then used this approach to boost capillary blood flow by selective expression of Halorhodopsin, a highly precise hyperpolarizing optogenetic actuator. The ability to exclusively target capillary pericytes may prove a precise and potentially powerful tool to treat microcirculation deficits, a common pathology in numerous diseases.
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Affiliation(s)
- Elena Ivanova
- Burke Neurological Institute, White Plains, New York, USA.,Department of Ophthalmology, BMRI, Weill Cornell Medicine, New York, New York, USA
| | - Carlo Corona
- Burke Neurological Institute, White Plains, New York, USA
| | | | | | - Botir T Sagdullaev
- Burke Neurological Institute, White Plains, New York, USA.,Department of Ophthalmology, BMRI, Weill Cornell Medicine, New York, New York, USA
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11
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Yoon HH, Nam MH, Choi I, Min J, Jeon SR. Optogenetic inactivation of the entopeduncular nucleus improves forelimb akinesia in a Parkinson's disease model. Behav Brain Res 2020; 386:112551. [PMID: 32057827 DOI: 10.1016/j.bbr.2020.112551] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 02/04/2020] [Accepted: 02/08/2020] [Indexed: 11/28/2022]
Abstract
We performed optogenetic inactivation of rats' entopeduncular nucleus (EP, homologous to primates' globus pallidus interna (GPi)) and investigated the therapeutic effect in a rat model of PD. 6-Hydroxydopamine (6-OHDA)-induced hemiparkinsonian rats were injected with either a virus for halorhodopsin expression that is used to inactivate GABAergic neurons or a control virus injection and received optic fiber insertion. All the rats were illuminated by 590 nm of light. Each rat was then subjected to sequential sessions of stepping tests under controlled illumination patterns. The stepping test is a reliable evaluation method for forelimb akinesia. The number of adjusting steps was significantly higher in experimental (optogene with reporter gene expression) (5Hz - 10ms: 15.7 ± 1.9, 5Hz - 100ms: 16.0 ± 1.8, continuous: 21.6 ± 1.9) than control rats (reporter gene expression) (5Hz-10ms: 1.9 ± 1.1, 5Hz-100ms: 2.6 ± 1.0, continuous: 2.5 ± 1.2) (p < 0.001). Continuous EP illumination showed a significantly higher improvement of forelimb akinesia than other illumination patterns (p < 0.01). Optogene expression in the GABAergic neurons of the EP was confirmed by immunohistochemistry. Optogenetic inhibition of EP was effective to improve contralateral forelimb akinesia. However, further studies using prolonged illumination are needed to investigate the best illumination pattern for optogenetic stimulation.
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Affiliation(s)
- Hyung Ho Yoon
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
| | - Min-Ho Nam
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Il Choi
- Department of Neurosurgery, Hallym University, Dongtan Sacred Heart Hospital, 7, Keunjaebong-gil, Hwaseong-si, Gyeonggi-do 445-907, Republic of Korea
| | - Joongkee Min
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
| | - Sang Ryong Jeon
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.
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12
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Zhang C, Yang S, Flossmann T, Gao S, Witte OW, Nagel G, Holthoff K, Kirmse K. Optimized photo-stimulation of halorhodopsin for long-term neuronal inhibition. BMC Biol 2019; 17:95. [PMID: 31775747 PMCID: PMC6882325 DOI: 10.1186/s12915-019-0717-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 10/30/2019] [Indexed: 01/04/2023] Open
Abstract
Background Optogenetic silencing techniques have expanded the causal understanding of the functions of diverse neuronal cell types in both the healthy and diseased brain. A widely used inhibitory optogenetic actuator is eNpHR3.0, an improved version of the light-driven chloride pump halorhodopsin derived from Natronomonas pharaonis. A major drawback of eNpHR3.0 is related to its pronounced inactivation on a time-scale of seconds, which renders it unsuited for applications that require long-lasting silencing. Results Using transgenic mice and Xenopus laevis oocytes expressing an eNpHR3.0-EYFP fusion protein, we here report optimized photo-stimulation techniques that profoundly increase the stability of eNpHR3.0-mediated currents during long-term photo-stimulation. We demonstrate that optimized photo-stimulation enables prolonged hyperpolarization and suppression of action potential discharge on a time-scale of minutes. Conclusions Collectively, our findings extend the utility of eNpHR3.0 to the long-lasting inhibition of excitable cells, thus facilitating the optogenetic dissection of neural circuits.
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Affiliation(s)
- Chuanqiang Zhang
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.,Present Address: Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Shang Yang
- Institute for Molecular Plant Physiology and Biophysics, Biocenter, & Institute of Physiology - Neurophysiology, Julius-Maximilians-University of Würzburg, 97070, Würzburg, Germany
| | - Tom Flossmann
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.,Present Address: Centre for Discovery Brain Sciences, Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Shiqiang Gao
- Institute for Molecular Plant Physiology and Biophysics, Biocenter, & Institute of Physiology - Neurophysiology, Julius-Maximilians-University of Würzburg, 97070, Würzburg, Germany
| | - Otto W Witte
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - Georg Nagel
- Institute for Molecular Plant Physiology and Biophysics, Biocenter, & Institute of Physiology - Neurophysiology, Julius-Maximilians-University of Würzburg, 97070, Würzburg, Germany
| | - Knut Holthoff
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - Knut Kirmse
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.
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Hasemi T, Kikukawa T, Watanabe Y, Aizawa T, Miyauchi S, Kamo N, Demura M. Photochemical study of a cyanobacterial chloride-ion pumping rhodopsin. Biochim Biophys Acta Bioenerg 2018; 1860:136-146. [PMID: 30529327 DOI: 10.1016/j.bbabio.2018.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/30/2018] [Accepted: 12/04/2018] [Indexed: 10/27/2022]
Abstract
Mastigocladopsis repens halorhodopsin (MrHR) is a Cl--pumping rhodopsin that belongs to a distinct cluster far from other Cl- pumps. We investigated its pumping function by analyzing its photocycle and the effect of amino acid replacements. MrHR can bind I- similar to Cl- but cannot transport it. I--bound MrHR undergoes a photocycle but lacks the intermediates after L, suggesting that, in the Cl--pumping photocycle, Cl- moves to the cytoplasmic (CP) channel during L decay. A photocycle similar to that of the I--bound form was also observed for a mutant of the Asp200 residue, which is superconserved and assumed to be deprotonated in most microbial rhodopsins. This residue is probably close to the Cl--binding site and the protonated Schiff base, in which a chromophore retinal binds to a specific Lys residue. However, the D200N mutation affected neither the Cl--binding affinity nor the absorption spectrum, but completely eliminated the Cl--pumping function. Thus, the Asp200 residue probably protonates in the dark state but deprotonates during the photocycle. Indeed, a H+ release was detected for photolyzed MrHR by using an indium‑tin oxide electrode, which acts as a good time-resolved pH sensor. This H+ release disappeared in the I--bound form of the wild-type and Cl--bound form of the D200N mutant. Thus, Asp200 residue probably deprotonates during L decay and then drives the Cl- movement to the CP channel.
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Affiliation(s)
- Takatoshi Hasemi
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Takashi Kikukawa
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan; Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo 060-0810, Japan.
| | - Yumi Watanabe
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Tomoyasu Aizawa
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan; Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo 060-0810, Japan
| | - Seiji Miyauchi
- Graduate School of Pharmaceutical Sciences, Toho University, Chiba 274-8510, Japan
| | - Naoki Kamo
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Makoto Demura
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan; Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo 060-0810, Japan
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Sakajiri Y, Sugano E, Watanabe Y, Sakajiri T, Tabata K, Kikuchi T, Tomita H. Natronomonas pharaonis halorhodopsin Ser81 plays a role in maintaining chloride ions near the Schiff base. Biochem Biophys Res Commun 2018; 503:2326-2332. [PMID: 29964009 DOI: 10.1016/j.bbrc.2018.06.156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 06/27/2018] [Indexed: 02/02/2023]
Abstract
Optogenetic technologies have often been used as tools for neuronal activation or silencing by light. Natronomonas pharaonis halorhodopsin (NpHR) is a light-driven chloride ion pump. Upon light absorption, a chloride ion passes through the cell membrane, which is accompanied by the temporary binding of a chloride ion with Thr126 at binding site-1 (BS1) near the protonated Schiff base in NpHR. However, the mechanism of stabilization of the binding state between a chloride ion and BS1 has not been investigated. Therefore, to identify a key component of the chloride ion transport pathway as well as to acquire dynamic information about the chloride ion-BS1 binding state, we performed a rough analysis of the chloride ion pathway shape followed by molecular dynamics (MD) simulations for both wild-type and mutant NpHR structures. The MD simulations showed that the hydrogen bond between Thr126 and the chloride ion was retained in the wild-type protein, while the chloride ion could not be retained at and tended to leave BS1 in the S81A mutant. We found that the direction of the Thr126 side chain was fixed by a hydroxyl group of Ser81 through a hydrogen bond and that Thr126 bound to a chloride ion in the wild-type protein, while this interaction was lost in the S81A mutant, resulting in rotation of the Thr126 side chain and reduction in the interaction between Thr126 and a chloride ion. To confirm the role of S81, patch clamp recordings were performed using cells expressing NpHR S81A mutant protein. Considered together with the results that the NpHR S81A-expressing cells did not undergo hyperpolarization under light stimulation, our results indicate that Ser81 plays a key role in chloride migration. Our findings might be relevant to ongoing clinical trials using optogenetic gene therapy in blind patients.
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Affiliation(s)
- Yuko Sakajiri
- The United Graduate School of Agricultural Sciences, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan.
| | - Eriko Sugano
- The United Graduate School of Agricultural Sciences, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan; Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University, 4-3-5 Ueda, Morioka, Iwate, 020-8551, Japan.
| | - Yoshito Watanabe
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University, 4-3-5 Ueda, Morioka, Iwate, 020-8551, Japan.
| | - Tetsuya Sakajiri
- Department of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan.
| | - Kitako Tabata
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University, 4-3-5 Ueda, Morioka, Iwate, 020-8551, Japan.
| | - Takeshi Kikuchi
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu Shiga, 525-8577, Japan.
| | - Hiroshi Tomita
- The United Graduate School of Agricultural Sciences, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan; Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University, 4-3-5 Ueda, Morioka, Iwate, 020-8551, Japan; Clinical Research, Innovation and Education Center, Tohoku University Hospital, 1-1 Seiryo, Aoba, Sendai, Miyagi, 980-8574, Japan.
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Lee EJ, Yoon HH, Park ES, Min J, Jeon SR. A Novel Animal Model of Parkinson's Disease Using Optogenetics: Representation of Various Disease Stages by Modulating the Illumination Parameter. Stereotact Funct Neurosurg 2018; 96:22-32. [PMID: 29444523 DOI: 10.1159/000486644] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 01/08/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND The classic animal model of Parkinson's disease (PD) using neurotoxin can only simulate fixed stages of the disease by causing irreversible damage to the nigrostriatal system. OBJECTIVES To develop an optogenetic PD model that can modulate the severity of disease by optical stimulation by introducing the halorhodopsin (NpHR) gene into the substantia nigra compacta. METHODS Fifteen rats received injections of engineered AAV with NpHR-YFP gene into the substantia nigra. They were then subjected to illumination of 590-nm light wavelengths with 3 optical stimulation conditions, i.e., frequency-width: 5 Hz-10 ms (n = 5), 5 Hz-100 ms (n = 5), and 50 Hz-10 ms (n = 5). Eleven rats received 6-hydroxydopamine injections to establish the conventional PD model. RESULTS The optogenetic models showed characteristic PD manifestations, similar to those of the conventional models; the severity of forelimb akinesia correlated with the total illumination value (frequency × width). The group with a low illumination value (5 Hz-10 ms) was comparable to the conventional partial model whereas the groups with high illumination values (5 Hz-100 ms and 50 Hz-10 ms) were similar to the conventional complete model. CONCLUSIONS An optogenetic PD model has the advantage of more appropriately representing various PD stages by controlling illumination parameters.
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Affiliation(s)
- Eun Jung Lee
- Department of Neurosurgery, Hallym University Dongtan Sacred Heart Hospital, Hwaseong-si, Republic of Korea
| | - Hyung Ho Yoon
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Eun Suk Park
- Department of Neurosurgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | - Joongkee Min
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang Ryong Jeon
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
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16
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Amtul Z, Aziz AA. Microbial Proteins as Novel Industrial Biotechnology Hosts to Treat Epilepsy. Mol Neurobiol 2016; 54:8211-8224. [PMID: 27905012 DOI: 10.1007/s12035-016-0279-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 10/31/2016] [Indexed: 12/16/2022]
Abstract
Epilepsy is characterized by the hyperexcitability of various neuronal circuits that results due to the imbalance between glutamate-mediated excitation of voltage-gated cation channels and γ-amino butyric acid (GABA)-mediated inhibition of anion channels leading to aberrant, sporadic oscillations or fluctuations in neuronal electrical activity. Epilepsy with a risk of mortality and around 65 million sufferers of all ages all over the world is limited therapeutically with high rates of adverse reactions, lack of complete seizure control, and over 30% patients with refractory epilepsy. The only alternative to medicines is to identify and surgically remove the seizure foci in the brain or to abort the seizures just as they begin using an implanted cerebral electrode. However, these alternatives are unable to precisely aim aberrant neuronal circuits while leaving others unaltered. Epilepsy animal models also constitute the identical constraint. Thus, a better target-specific approach is needed to study and treat epilepsy. Unicellular green algae Chlamydomonas reinhardtii expresses a channelrhodopsin-2 (ChR2) sodium ion channel protein that controls the phototaxis movement of algae in response to blue light. Similarly, archaeon Natronomonas pharaonis (NpHR) expresses a monovalent Cl- channel protein halorhodopsin that responds to yellow light. These features of ChR2 and NpHR proteins can be used in optogenetic techniques to manipulate the bi-directional firing pattern of neuronal circuits in an attempt to better understand the pathophysiology of epileptic seizures as well as to discover novel potential drugs to treat epilepsy.
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Affiliation(s)
- Zareen Amtul
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.
| | - Amal A Aziz
- Sir Wilfrid Laurier Secondary School, Thames Valley District School Board, N6C 4W7, London, ON, Canada
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Hsiao PY, Wu MC, Lin YY, Fu CC, Chiang AS. Optogenetic Manipulation of Selective Neural Activity in Free-Moving Drosophila Adults. Methods Mol Biol 2016; 1408:377-87. [PMID: 26965137 DOI: 10.1007/978-1-4939-3512-3_26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Activating selected neurons elicits specific behaviors in Drosophila adults. By combining optogenetics and laser-tracking techniques, we have recently developed an automated laser-tracking and optogenetic manipulation system (ALTOMS) for studying how brain circuits orchestrate complex behaviors. The established ALTOMS can independently target three lasers (473-nm blue laser, 593.5-nm yellow laser, and 1064-nm infrared laser) on any specified body part of two freely moving flies. Triggering light-sensitive proteins in real time, the blue laser and yellow laser can respectively activate and inhibit target neurons in artificial transgenic flies. Since infrared light is invisible to flies, we use the 1064-nm laser as an aversive stimulus in operant learning without perturbing visual inputs. Herein, we provide a detailed protocol for the construction of ALTOMS and optogenetic manipulation of target neurons in Drosophila adults during social interactions.
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Abstract
The activity-dependent refinement of neural circuit connectivity during critical periods of brain development is essential for optimized behavioral performance. We hypothesize that this mechanism is defective in fragile X syndrome (FXS), the leading heritable cause of intellectual disability and autism spectrum disorders. Here, we use optogenetic tools in the Drosophila FXS disease model to test activity-dependent dendritogenesis in two extrinsic neurons of the mushroom body (MB) learning and memory brain center: (1) the input projection neuron (PN) innervating Kenyon cells (KCs) in the MB calyx microglomeruli and (2) the output MVP2 neuron innervated by KCs in the MB peduncle. Both input and output neuron classes exhibit distinctive activity-dependent critical period dendritic remodeling. MVP2 arbors expand in Drosophila mutants null for fragile X mental retardation 1 (dfmr1), as well as following channelrhodopsin-driven depolarization during critical period development, but are reduced by halorhodopsin-driven hyperpolarization. Optogenetic manipulation of PNs causes the opposite outcome--reduced dendritic arbors following channelrhodopsin depolarization and expanded arbors following halorhodopsin hyperpolarization during development. Importantly, activity-dependent dendritogenesis in both neuron classes absolutely requires dfmr1 during one developmental window. These results show that dfmr1 acts in a neuron type-specific activity-dependent manner for sculpting dendritic arbors during early-use, critical period development of learning and memory circuitry in the Drosophila brain.
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Affiliation(s)
- Caleb A Doll
- Department of Biological Sciences, Department of Cell and Developmental Biology, The Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Department of Cell and Developmental Biology, The Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
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Dutta S, Hirshfeld A, Sheves M. The role of retinal light induced dipole in halorhodopsin structural alteration. FEBS Lett 2015; 589:3576-80. [PMID: 26467279 DOI: 10.1016/j.febslet.2015.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/05/2015] [Accepted: 10/02/2015] [Indexed: 11/20/2022]
Abstract
The present work studies the mechanism of light induced protein conformational changes in the over-expressed mutant of halorhodopsin (phR) from Natronomonas pharaonis. The catalytic effect of light is reflected in accelerating hydroxyl amine reaction rate of light adapted phR. Light catalysis was detected in native phR but also in artificial pigments derived from tailored retinal analogs locked at the crucial C13=C14 double bond. It is proposed that the photoexcited retinal chromophore induces protein concerted motion that decreases the energy gap between reactants ground and transition states. This energy gap is overcome by coupling to specific protein vibrations. Surprisingly, the rate constants show unusual decreasing trend following temperature increase both for native and artificial pigments.
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20
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Glock C, Nagpal J, Gottschalk A. Microbial Rhodopsin Optogenetic Tools: Application for Analyses of Synaptic Transmission and of Neuronal Network Activity in Behavior. Methods Mol Biol 2015; 1327:87-103. [PMID: 26423970 DOI: 10.1007/978-1-4939-2842-2_8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Optogenetics was introduced as a new technology in the neurosciences about a decade ago (Zemelman et al., Neuron 33:15-22, 2002; Boyden et al., Nat Neurosci 8:1263-1268, 2005; Nagel et al., Curr Biol 15:2279-2284, 2005; Zemelman et al., Proc Natl Acad Sci USA 100:1352-1357, 2003). It combines optics, genetics, and bioengineering to render neurons sensitive to light, in order to achieve a precise, exogenous, and noninvasive control of membrane potential, intracellular signaling, network activity, or behavior (Rein and Deussing, Mol Genet Genomics 287:95-109, 2012; Yizhar et al., Neuron 71:9-34, 2011). As C. elegans is transparent, genetically amenable, has a small nervous system mapped with synapse resolution, and exhibits a rich behavioral repertoire, it is especially open to optogenetic methods (White et al., Philos Trans R Soc Lond B Biol Sci 314:1-340, 1986; De Bono et al., Optogenetic actuation, inhibition, modulation and readout for neuronal networks generating behavior in the nematode Caenorhabditis elegans, In: Hegemann P, Sigrist SJ (eds) Optogenetics, De Gruyter, Berlin, 2013; Husson et al., Biol Cell 105:235-250, 2013; Xu and Kim, Nat Rev Genet 12:793-801, 2011). Optogenetics, by now an "exploding" field, comprises a repertoire of different tools ranging from transgenically expressed photo-sensor proteins (Boyden et al., Nat Neurosci 8:1263-1268, 2005; Nagel et al., Curr Biol 15:2279-2284, 2005) or cascades (Zemelman et al., Neuron 33:15-22, 2002) to chemical biology approaches, using photochromic ligands of endogenous channels (Szobota et al., Neuron 54:535-545, 2007). Here, we will focus only on optogenetics utilizing microbial rhodopsins, as these are most easily and most widely applied in C. elegans. For other optogenetic tools, for example the photoactivated adenylyl cyclases (PACs, that drive neuronal activity by increasing synaptic vesicle priming, thus exaggerating rather than overriding the intrinsic activity of a neuron, as occurs with rhodopsins), we refer to other literature (Weissenberger et al., J Neurochem 116:616-625, 2011; Steuer Costa et al., Photoactivated adenylyl cyclases as optogenetic modulators of neuronal activity, In: Cambridge S (ed) Photswitching proteins, Springer, New York, 2014). In this chapter, we will give an overview of rhodopsin-based optogenetic tools, their properties and function, as well as their combination with genetically encoded indicators of neuronal activity. As there is not "the" single optogenetic experiment we could describe here, we will focus more on general concepts and "dos and don'ts" when designing an optogenetic experiment. We will also give some guidelines on which hardware to use, and then describe a typical example of an optogenetic experiment to analyze the function of the neuromuscular junction, and another application, which is Ca(2+) imaging in body wall muscle, with upstream neuronal excitation using optogenetic stimulation. To obtain a more general overview of optogenetics and optogenetic tools, we refer the reader to an extensive collection of review articles, and in particular to volume 1148 of this book series, "Photoswitching Proteins."
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Mantoan Ritter L, Golshani P, Takahashi K, Dufour S, Valiante T, Kokaia M. WONOEP appraisal: optogenetic tools to suppress seizures and explore the mechanisms of epileptogenesis. Epilepsia 2014; 55:1693-702. [PMID: 25303540 DOI: 10.1111/epi.12804] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2014] [Indexed: 02/04/2023]
Abstract
Optogenetics is a novel technology that combines optics and genetics by optical control of microbial opsins, targeted to living cell membranes. The versatility and the electrophysiologic characteristics of the light-sensitive ion-channels channelrhodopsin-2 (ChR2), halorhodopsin (NpHR), and the light-sensitive proton pump archaerhodopsin-3 (Arch) make these optogenetic tools potent candidates in controlling neuronal firing in models of epilepsy and in providing insights into the physiology and pathology of neuronal network organization and synchronization. Opsins allow selective activation of excitatory neurons and inhibitory interneurons, or subclasses of interneurons, to study their activity patterns in distinct brain-states in vivo and to dissect their role in generation of synchrony and seizures. The influence of gliotransmission on epileptic network function is another topic of great interest that can be further explored by using light-activated Gq protein-coupled opsins for selective activation of astrocytes. The ever-growing optogenetic toolbox can also be combined with emerging techniques that have greatly expanded our ability to record specific subtypes of cortical and hippocampal neurons in awake behaving animals such as juxtacellular recording and two-photon guided whole-cell recording, to identify the specific subtypes of neurons that are altered in epileptic networks. Finally, optogenetic tools allow rapid and reversible suppression of epileptic electroencephalography (EEG) activity upon photoactivation. This review outlines the most recent advances achieved with optogenetic techniques in the field of epilepsy by summarizing the presentations contributed to the 13th ILAE WONOEP meeting held in the Laurentian Mountains, Quebec, in June 2013.
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Affiliation(s)
- Laura Mantoan Ritter
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, United Kingdom
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Stubblefield EA, Costabile JD, Felsen G. Optogenetic investigation of the role of the superior colliculus in orienting movements. Behav Brain Res 2013; 255:55-63. [PMID: 23643689 DOI: 10.1016/j.bbr.2013.04.040] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Revised: 03/27/2013] [Accepted: 04/25/2013] [Indexed: 12/13/2022]
Abstract
In vivo studies have demonstrated that the superior colliculus (SC) integrates sensory information and plays a role in controlling orienting motor output. However, how the complex microcircuitry within the SC, as documented by slice studies, subserves these functions is unclear. Optogenetics affords the potential to examine, in behaving animals, the functional roles of specific neuron types that comprise heterogeneous nuclei. As a first step toward understanding how SC microcircuitry underlies motor output, we applied optogenetics to mice performing an odor discrimination task in which sensory decisions are reported by either a leftward or rightward SC-dependent orienting movement. We unilaterally expressed either channelrhodopsin-2 or halorhodopsin in the SC and delivered light in order to excite or inhibit motor-related SC activity as the movement was planned. We found that manipulating SC activity predictably affected the direction of the selected movement in a manner that depended on the difficulty of the odor discrimination. This study demonstrates that the SC plays a similar role in directional orienting movements in mice as it does in other species, and provides a framework for future investigations into how specific SC cell types contribute to motor control.
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Ting JT, Feng G. Development of transgenic animals for optogenetic manipulation of mammalian nervous system function: progress and prospects for behavioral neuroscience. Behav Brain Res 2013; 255:3-18. [PMID: 23473879 DOI: 10.1016/j.bbr.2013.02.037] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 02/14/2013] [Accepted: 02/23/2013] [Indexed: 12/21/2022]
Abstract
Here we review the rapidly growing toolbox of transgenic mice and rats that exhibit functional expression of engineered opsins for neuronal activation and silencing with light. Collectively, these transgenic animals are enabling neuroscientists to access and manipulate the many diverse cell types in the mammalian nervous system in order to probe synaptic and circuitry connectivity, function, and dysfunction. The availability of transgenic lines affords important advantages such as stable and heritable transgene expression patterns across experimental cohorts. As such, the use of transgenic lines precludes the need for other costly and labor-intensive procedures to achieve functional transgene expression in each individual experimental animal. This represents an important consideration when large cohorts of experimental animals are desirable as in many common behavioral assays. We describe the diverse strategies that have been implemented for developing transgenic mouse and rat lines and highlight recent advances that have led to dramatic improvements in achieving functional transgene expression of engineered opsins. Furthermore, we discuss considerations and caveats associated with implementing recently developed transgenic lines for optogenetics-based experimentation. Lastly, we propose strategies that can be implemented to develop and refine the next generation of genetically modified animals for behaviorally-focused optogenetics-based applications.
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Affiliation(s)
- Jonathan T Ting
- McGovern Institute for Brain Research and Department of Brain & Cognitive Sciences, MIT, Cambridge, MA 02139, USA.
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