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Broussard JI, Redell JB, Zhao J, West R, Homma R, Dash PK. Optogenetic Stimulation of CA1 Pyramidal Neurons at Theta Enhances Recognition Memory in Brain Injured Animals. J Neurotrauma 2023; 40:2442-2448. [PMID: 37387400 PMCID: PMC10653071 DOI: 10.1089/neu.2023.0078] [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: 07/01/2023] Open
Abstract
Abstract The hippocampus plays a prominent role in learning and memory formation. The functional integrity of this structure is often compromised after traumatic brain injury (TBI), resulting in lasting cognitive dysfunction. The activity of hippocampal neurons, particularly place cells, is coordinated by local theta oscillations. Previous studies aimed at examining hippocampal theta oscillations after experimental TBI have reported disparate findings. Using a diffuse brain injury model, the lateral fluid percussion injury (FPI; 2.0 atm), we report a significant reduction in hippocampal theta power that persists for at least three weeks after injury. We questioned whether the behavioral deficit associated with this reduction of theta power can be overcome by optogenetically stimulating CA1 neurons at theta in brain injured rats. Our results show that memory impairments in brain injured animals could be reversed by optogenetically stimulating CA1 pyramidal neurons expressing channelrhodopsin (ChR2) during learning. In contrast, injured animals receiving a control virus (lacking ChR2) did not benefit from optostimulation. These results suggest that direct stimulation of CA1 pyramidal neurons at theta may be a viable option for enhancing memory after TBI.
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Affiliation(s)
- John I. Broussard
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - John B. Redell
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Jing Zhao
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Rebecca West
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Ryota Homma
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Pramod K. Dash
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
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Mitroshina E, Kalinina E, Vedunova M. Optogenetics in Alzheimer's Disease: Focus on Astrocytes. Antioxidants (Basel) 2023; 12:1856. [PMID: 37891935 PMCID: PMC10604138 DOI: 10.3390/antiox12101856] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/27/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia, resulting in disability and mortality. The global incidence of AD is consistently surging. Although numerous therapeutic agents with promising potential have been developed, none have successfully treated AD to date. Consequently, the pursuit of novel methodologies to address neurodegenerative processes in AD remains a paramount endeavor. A particularly promising avenue in this search is optogenetics, enabling the manipulation of neuronal activity. In recent years, research attention has pivoted from neurons to glial cells. This review aims to consider the potential of the optogenetic correction of astrocyte metabolism as a promising strategy for correcting AD-related disorders. The initial segment of the review centers on the role of astrocytes in the genesis of neurodegeneration. Astrocytes have been implicated in several pathological processes associated with AD, encompassing the clearance of β-amyloid, neuroinflammation, excitotoxicity, oxidative stress, and lipid metabolism (along with a critical role in apolipoprotein E function). The effect of astrocyte-neuronal interactions will also be scrutinized. Furthermore, the review delves into a number of studies indicating that changes in cellular calcium (Ca2+) signaling are one of the causes of neurodegeneration. The review's latter section presents insights into the application of various optogenetic tools to manipulate astrocytic function as a means to counteract neurodegenerative changes.
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Affiliation(s)
- Elena Mitroshina
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603022 Nizhny Novgorod, Russia (M.V.)
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Tajima S, Kim YS, Fukuda M, Jo Y, Wang PY, Paggi JM, Inoue M, Byrne EFX, Kishi KE, Nakamura S, Ramakrishnan C, Takaramoto S, Nagata T, Konno M, Sugiura M, Katayama K, Matsui TE, Yamashita K, Kim S, Ikeda H, Kim J, Kandori H, Dror RO, Inoue K, Deisseroth K, Kato HE. Structural basis for ion selectivity in potassium-selective channelrhodopsins. Cell 2023; 186:4325-4344.e26. [PMID: 37652010 PMCID: PMC7615185 DOI: 10.1016/j.cell.2023.08.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [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] [Received: 09/30/2022] [Revised: 05/11/2023] [Accepted: 08/07/2023] [Indexed: 09/02/2023]
Abstract
KCR channelrhodopsins (K+-selective light-gated ion channels) have received attention as potential inhibitory optogenetic tools but more broadly pose a fundamental mystery regarding how their K+ selectivity is achieved. Here, we present 2.5-2.7 Å cryo-electron microscopy structures of HcKCR1 and HcKCR2 and of a structure-guided mutant with enhanced K+ selectivity. Structural, electrophysiological, computational, spectroscopic, and biochemical analyses reveal a distinctive mechanism for K+ selectivity; rather than forming the symmetrical filter of canonical K+ channels achieving both selectivity and dehydration, instead, three extracellular-vestibule residues within each monomer form a flexible asymmetric selectivity gate, while a distinct dehydration pathway extends intracellularly. Structural comparisons reveal a retinal-binding pocket that induces retinal rotation (accounting for HcKCR1/HcKCR2 spectral differences), and design of corresponding KCR variants with increased K+ selectivity (KALI-1/KALI-2) provides key advantages for optogenetic inhibition in vitro and in vivo. Thus, discovery of a mechanism for ion-channel K+ selectivity also provides a framework for next-generation optogenetics.
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Affiliation(s)
- Seiya Tajima
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Yoon Seok Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Masahiro Fukuda
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - YoungJu Jo
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Peter Y Wang
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Joseph M Paggi
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Masatoshi Inoue
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Eamon F X Byrne
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Koichiro E Kishi
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Seiwa Nakamura
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | | | - Shunki Takaramoto
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Takashi Nagata
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Masae Konno
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Masahiro Sugiura
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Japan
| | - Kota Katayama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Japan
| | - Toshiki E Matsui
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Keitaro Yamashita
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Suhyang Kim
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Hisako Ikeda
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Jaeah Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Japan
| | - Ron O Dror
- Department of Computer Science, Stanford University, Stanford, CA, USA; Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, USA; CNC Program, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA; Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA.
| | - Hideaki E Kato
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan; FOREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan.
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4
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Murata J, Unekawa M, Kudo Y, Kotani M, Kanno I, Izawa Y, Tomita Y, Tanaka KF, Nakahara J, Masamoto K. Acceleration of the Development of Microcirculation Embolism in the Brain due to Capillary Narrowing. Stroke 2023; 54:2135-2144. [PMID: 37309687 DOI: 10.1161/strokeaha.122.042416] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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] [Received: 12/30/2022] [Accepted: 05/05/2023] [Indexed: 06/14/2023]
Abstract
BACKGROUND Cerebral microvascular obstruction is critically involved in recurrent stroke and decreased cerebral blood flow with age. The obstruction must occur in the capillary with a greater resistance to perfusion pressure through the microvascular networks. However, little is known about the relationship between capillary size and embolism formation. This study aimed to determine whether the capillary lumen space contributes to the development of microcirculation embolism. METHODS To spatiotemporally manipulate capillary diameters in vivo, transgenic mice expressing the light-gated cation channel protein ChR2 (channelrhodopsin-2) in mural cells were used. The spatiotemporal changes in the regional cerebral blood flow in response to the photoactivation of ChR2 mural cells were first characterized using laser speckle flowgraphy. Capillary responses to optimized photostimulation were then examined in vivo using 2-photon microscopy. Finally, microcirculation embolism due to intravenously injected fluorescent microbeads was compared under conditions with or without photoactivation of ChR2 mural cells. RESULTS Following transcranial photostimulation, the stimulation intensity-dependent decrease in cerebral blood flow centered at the irradiation was observed (14%-49% decreases relative to the baseline). The cerebrovascular response to photostimulation showed significant constriction of the cerebral arteries and capillaries but not of the veins. As a result of vasoconstriction, a temporal stall of red blood cell flow occurred in the capillaries of the venous sides. The 2-photon excitation of a single ChR2 pericyte demonstrated the partial shrinkage of capillaries (7% relative to the baseline) around the stimulated cell. With the intravenous injection of microbeads, the occurrence of microcirculation embolism was significantly enhanced (11% increases compared to the control) with photostimulation. CONCLUSIONS Capillary narrowing increases the risk of developing microcirculation embolism in the venous sides of the cerebral capillaries.
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Affiliation(s)
- Juri Murata
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
| | - Miyuki Unekawa
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
| | - Yuya Kudo
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
| | - Maho Kotani
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
| | - Iwao Kanno
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, Japan (I.K.)
| | - Yoshikane Izawa
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
| | - Yutaka Tomita
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
- Tomita Hospital, Aichi, Japan (Y.T.)
| | - Kenji F Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research (K.F.T.), Keio University School of Medicine, Tokyo, Japan
| | - Jin Nakahara
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
| | - Kazuto Masamoto
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
- Center for Neuroscience and Biomedical Engineering (K.M.), University of Electro-Communications, Tokyo, Japan
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Rindner DJ, Lur G. Practical considerations in an era of multicolor optogenetics. Front Cell Neurosci 2023; 17:1160245. [PMID: 37293628 PMCID: PMC10244638 DOI: 10.3389/fncel.2023.1160245] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 05/05/2023] [Indexed: 06/10/2023] Open
Abstract
The ability to control synaptic communication is indispensable to modern neuroscience. Until recently, only single-pathway manipulations were possible due to limited availability of opsins activated by distinct wavelengths. However, extensive protein engineering and screening efforts have drastically expanded the optogenetic toolkit, ushering in an era of multicolor approaches for studying neural circuits. Nonetheless, opsins with truly discrete spectra are scarce. Experimenters must therefore take care to avoid unintended cross-activation of optogenetic tools (crosstalk). Here, we demonstrate the multidimensional nature of crosstalk in a single model synaptic pathway, testing stimulus wavelength, irradiance, duration, and opsin choice. We then propose a "lookup table" method for maximizing the dynamic range of opsin responses on an experiment-by-experiment basis.
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Affiliation(s)
| | - Gyorgy Lur
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
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Gao TT, Oh TJ, Mehta K, Huang YEA, Camp T, Fan H, Han JW, Barnes CM, Zhang K. The clinical potential of optogenetic interrogation of pathogenesis. Clin Transl Med 2023; 13:e1243. [PMID: 37132114 PMCID: PMC10154842 DOI: 10.1002/ctm2.1243] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/05/2023] [Accepted: 04/13/2023] [Indexed: 05/04/2023] Open
Abstract
BACKGROUND Opsin-based optogenetics has emerged as a powerful biomedical tool using light to control protein conformation. Such capacity has been initially demonstrated to control ion flow across the cell membrane, enabling precise control of action potential in excitable cells such as neurons or muscle cells. Further advancement in optogenetics incorporates a greater variety of photoactivatable proteins and results in flexible control of biological processes, such as gene expression and signal transduction, with commonly employed light sources such as LEDs or lasers in optical microscopy. Blessed by the precise genetic targeting specificity and superior spatiotemporal resolution, optogenetics offers new biological insights into physiological and pathological mechanisms underlying health and diseases. Recently, its clinical potential has started to be capitalized, particularly for blindness treatment, due to the convenient light delivery into the eye. AIMS AND METHODS This work summarizes the progress of current clinical trials and provides a brief overview of basic structures and photophysics of commonly used photoactivable proteins. We highlight recent achievements such as optogenetic control of the chimeric antigen receptor, CRISPR-Cas system, gene expression, and organelle dynamics. We discuss conceptual innovation and technical challenges faced by current optogenetic research. CONCLUSION In doing so, we provide a framework that showcases ever-growing applications of optogenetics in biomedical research and may inform novel precise medicine strategies based on this enabling technology.
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Affiliation(s)
- Tianyu Terry Gao
- University of Illinois at Urbana-Champaign, Department of Biochemistry, Urbana, Illinois, USA
| | - Teak-Jung Oh
- University of Illinois at Urbana-Champaign, Department of Biochemistry, Urbana, Illinois, USA
| | - Kritika Mehta
- University of Illinois at Urbana-Champaign, Department of Biochemistry, Urbana, Illinois, USA
| | - Yu-En Andrew Huang
- University of Illinois at Urbana-Champaign, Center for Biophysics and Quantitative Biology, Urbana, Illinois, USA
| | - Tyler Camp
- University of Illinois at Urbana-Champaign, Department of Biochemistry, Urbana, Illinois, USA
| | - Huaxun Fan
- University of Illinois at Urbana-Champaign, Department of Biochemistry, Urbana, Illinois, USA
| | - Jeong Won Han
- University of Illinois at Urbana-Champaign, Department of Biochemistry, Urbana, Illinois, USA
| | - Collin Michael Barnes
- University of Illinois at Urbana-Champaign, Department of Biochemistry, Urbana, Illinois, USA
| | - Kai Zhang
- University of Illinois at Urbana-Champaign, Department of Biochemistry, Urbana, Illinois, USA
- University of Illinois at Urbana-Champaign, Center for Biophysics and Quantitative Biology, Urbana, Illinois, USA
- Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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Hatakeyama A, Sugano E, Sayama T, Watanabe Y, Suzuki T, Tabata K, Endo Y, Sakajiri T, Fukuda T, Ozaki T, Tomita H. Properties of a Single Amino Acid Residue in the Third Transmembrane Domain Determine the Kinetics of Ambient Light-Sensitive Channelrhodopsin. Int J Mol Sci 2023; 24:ijms24055054. [PMID: 36902480 PMCID: PMC10003734 DOI: 10.3390/ijms24055054] [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] [Received: 02/08/2023] [Revised: 03/02/2023] [Accepted: 03/04/2023] [Indexed: 03/09/2023] Open
Abstract
Channelrhodopsins have been utilized in gene therapy to restore vision in patients with retinitis pigmentosa and their channel kinetics are an important factor to consider in such applications. We investigated the channel kinetics of ComV1 variants with different amino acid residues at the 172nd position. Patch clamp methods were used to record the photocurrents induced by stimuli from diodes in HEK293 cells transfected with plasmid vectors. The channel kinetics (τon and τoff) were considerably altered by the replacement of the 172nd amino acid and was dependent on the amino acid characteristics. The size of amino acids at this position correlated with τon and decay, whereas the solubility correlated with τon and τoff. Molecular dynamic simulation indicated that the ion tunnel constructed by H172, E121, and R306 widened due to H172A variant, whereas the interaction between A172 and the surrounding amino acids weakened compared with H172. The bottleneck radius of the ion gate constructed with the 172nd amino acid affected the photocurrent and channel kinetics. The 172nd amino acid in ComV1 is a key residue for determining channel kinetics as its properties alter the radius of the ion gate. Our findings can be used to improve the channel kinetics of channelrhodopsins.
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Stieve BJ, Smith MM, Krook-Magnuson E. LINCs Are Vulnerable to Epileptic Insult and Fail to Provide Seizure Control via On-Demand Activation. eNeuro 2023; 10:ENEURO.0195-22.2022. [PMID: 36725340 PMCID: PMC9933934 DOI: 10.1523/eneuro.0195-22.2022] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 12/13/2022] [Accepted: 12/19/2022] [Indexed: 02/03/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is notoriously pharmacoresistant, and identifying novel therapeutic targets for controlling seizures is crucial. Long-range inhibitory neuronal nitric oxide synthase-expressing cells (LINCs), a population of hippocampal neurons, were recently identified as a unique source of widespread inhibition in CA1, able to elicit both GABAA-mediated and GABAB-mediated postsynaptic inhibition. We therefore hypothesized that LINCs could be an effective target for seizure control. LINCs were optogenetically activated for on-demand seizure intervention in the intrahippocampal kainate (KA) mouse model of chronic TLE. Unexpectedly, LINC activation at 1 month post-KA did not substantially reduce seizure duration in either male or female mice. We tested two different sets of stimulation parameters, both previously found to be effective with on-demand optogenetic approaches, but neither was successful. Quantification of LINCs following intervention revealed a substantial reduction of LINC numbers compared with saline-injected controls. We also observed a decreased number of LINCs when the site of initial insult (i.e., KA injection) was moved to the amygdala [basolateral amygdala (BLA)-KA], and correspondingly, no effect of light delivery on BLA-KA seizures. This indicates that LINCs may be a vulnerable population in TLE, regardless of the site of initial insult. To determine whether long-term circuitry changes could influence outcomes, we continued testing once a month for up to 6 months post-KA. However, at no time point did LINC activation provide meaningful seizure suppression. Altogether, our results suggest that LINCs are not a promising target for seizure inhibition in TLE.
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Affiliation(s)
- Bethany J Stieve
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Madison M Smith
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Esther Krook-Magnuson
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
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Hyder SK, Ghosh A, Forcelli PA. Optogenetic activation of the superior colliculus attenuates spontaneous seizures in the pilocarpine model of temporal lobe epilepsy. Epilepsia 2023; 64:524-535. [PMID: 36448878 PMCID: PMC10907897 DOI: 10.1111/epi.17469] [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] [Received: 09/03/2022] [Revised: 11/04/2022] [Accepted: 11/17/2022] [Indexed: 12/03/2022]
Abstract
OBJECTIVE Decades of studies have indicated that activation of the deep and intermediate layers of the superior colliculus can suppress seizures in a wide range of experimental models of epilepsy. However, prior studies have not examined efficacy against spontaneous limbic seizures. The present study aimed to address this gap through chronic optogenetic activation of the superior colliculus in the pilocarpine model of temporal lobe epilepsy. METHODS Sprague Dawley rats underwent pilocarpine-induced status epilepticus and were maintained until the onset of spontaneous seizures. Virus coding for channelrhodopsin-2 was injected into the deep and intermediate layers of the superior colliculus, and animals were implanted with head-mounted light-emitting diodes at the same site. Rats were stimulated with either 5- or 100-Hz light delivery. Seizure number, seizure duration, 24-h seizure burden, and behavioral seizure severity were monitored. RESULTS Both 5- and 100-Hz optogenetic stimulation of the deep and intermediate layers of the superior colliculus reduced daily seizure number and total seizure burden in all animals in the active vector group. Stimulation did not affect either seizure duration or behavioral seizure severity. Stimulation was without effect in opsin-negative control animals. SIGNIFICANCE Activation of the deep and intermediate layers of the superior colliculus reduces both the number of seizures and total daily seizure burden in the pilocarpine model of temporal lobe epilepsy. These novel data demonstrating an effect against chronic experimental seizures complement a long history of studies documenting the antiseizure efficacy of superior colliculus activation in a range of acute seizure models.
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Affiliation(s)
- Safwan K. Hyder
- Department of Pharmacology & Physiology, Georgetown University, Washington DC, USA
| | - Anjik Ghosh
- Department of Pharmacology & Physiology, Georgetown University, Washington DC, USA
| | - Patrick A. Forcelli
- Department of Pharmacology & Physiology, Georgetown University, Washington DC, USA
- Department of Neuroscience, Georgetown University, Washington DC, USA
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington DC, USA
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Proskurina EY, Chizhov AV, Zaitsev AV. Optogenetic Low-Frequency Stimulation of Principal Neurons, but Not Parvalbumin-Positive Interneurons, Prevents Generation of Ictal Discharges in Rodent Entorhinal Cortex in an In Vitro 4-Aminopyridine Model. Int J Mol Sci 2022; 24:ijms24010195. [PMID: 36613660 PMCID: PMC9820186 DOI: 10.3390/ijms24010195] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/17/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022] Open
Abstract
Low-frequency electrical stimulation is used to treat some drug-resistant forms of epilepsy. Despite the effectiveness of the method in suppressing seizures, there is a considerable risk of side effects. An optogenetic approach allows the targeting of specific populations of neurons, which can increase the effectiveness and safety of low-frequency stimulation. In our study, we tested the efficacy of the suppression of ictal activity in entorhinal cortex slices in a 4-aminopyridine model with three variants of low-frequency light stimulation (LFLS): (1) activation of excitatory and inhibitory neurons (on Thy1-ChR2-YFP mice), (2) activation of inhibitory interneurons only (on PV-Cre mice after virus injection with channelrhodopsin2 gene), and (3) hyperpolarization of excitatory neurons (on Wistar rats after virus injection with archaerhodopsin gene). Only in the first variant did simultaneous LFLS of excitatory and inhibitory neurons replace ictal activity with interictal activity. We suggest that LFLS caused changes in the concentration gradients of K+ and Na+ cations across the neuron membrane, which activated Na-K pumping. According to the mathematical modeling, the increase in Na-K pump activity in neurons induced by LFLS led to an antiepileptic effect. Thus, a less specific and generalized optogenetic effect on entorhinal cortex neurons was more effective in suppressing ictal activity in the 4-aminopyridine model.
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Affiliation(s)
- Elena Y. Proskurina
- Almazov National Medical Research Centre, 2 Akkuratova Street, 197341 St. Petersburg, Russia
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, 44 Toreza Prospekt, 194223 St. Petersburg, Russia
| | - Anton V. Chizhov
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, 44 Toreza Prospekt, 194223 St. Petersburg, Russia
- Computational Physics Laboratory, Ioffe Institute, 26 Polytekhnicheskaya Street, 194021 St. Petersburg, Russia
- MathNeuro Team, Inria Centre at Universite Cote d’Azur, 06902 Sophia Antipolis, France
| | - Aleksey V. Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, 44 Toreza Prospekt, 194223 St. Petersburg, Russia
- Correspondence:
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Sakai D, Tomita H, Maeda A. Optogenetic Therapy for Visual Restoration. Int J Mol Sci 2022; 23. [PMID: 36499371 DOI: 10.3390/ijms232315041] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022] Open
Abstract
Optogenetics is a recent breakthrough in neuroscience, and one of the most promising applications is the treatment of retinal degenerative diseases. Multiple clinical trials are currently ongoing, less than a decade after the first attempt at visual restoration using optogenetics. Optogenetic therapy has great value in providing hope for visual restoration in late-stage retinal degeneration, regardless of the genotype. This alternative gene therapy consists of multiple elements including the choice of target retinal cells, optogenetic tools, and gene delivery systems. Currently, there are various options for each element, all of which have been developed as a product of technological success. In particular, the performance of optogenetic tools in terms of light and wavelength sensitivity have been improved by engineering microbial opsins and applying human opsins. To provide better post-treatment vision, the optimal choice of optogenetic tools and effective gene delivery to retinal cells is necessary. In this review, we provide an overview of the advancements in optogenetic therapy for visual restoration, focusing on available options for optogenetic tools and gene delivery methods.
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Jones JJ, Huang S, Hedrich R, Geilfus CM, Roelfsema MRG. The green light gap: a window of opportunity for optogenetic control of stomatal movement. New Phytol 2022; 236:1237-1244. [PMID: 36052708 DOI: 10.1111/nph.18451] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Green plants are equipped with photoreceptors that are capable of sensing radiation in the ultraviolet-to-blue and the red-to-far-red parts of the light spectrum. However, plant cells are not particularly sensitive to green light (GL), and light which lies within this part of the spectrum does not efficiently trigger the opening of stomatal pores. Here, we discuss the current knowledge of stomatal responses to light, which are either provoked via photosynthetically active radiation or by specific blue light (BL) signaling pathways. The limited impact of GL on stomatal movements provides a unique option to use this light quality to control optogenetic tools. Recently, several of these tools have been optimized for use in plant biological research, either to control gene expression, or to provoke ion fluxes. Initial studies with the BL-activated potassium channel BLINK1 showed that this tool can speed up stomatal movements. Moreover, the GL-sensitive anion channel GtACR1 can induce stomatal closure, even at conditions that provoke stomatal opening in wild-type plants. Given that crop plants in controlled-environment agriculture and horticulture are often cultivated with artificial light sources (i.e. a combination of blue and red light from light-emitting diodes), GL signals can be used as a remote-control signal that controls stomatal transpiration and water consumption.
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Affiliation(s)
- Jeffrey J Jones
- Division of Controlled Environment Horticulture, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Berlin, 14195, Germany
| | - Shouguang Huang
- Molecular Plant Physiology and Biophysics, Biocenter, University of Würzburg, 97082, Würzburg, Germany
| | - Rainer Hedrich
- Molecular Plant Physiology and Biophysics, Biocenter, University of Würzburg, 97082, Würzburg, Germany
| | - Christoph-Martin Geilfus
- Division of Controlled Environment Horticulture, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Berlin, 14195, Germany
- Department of Soil Science and Plant Nutrition, Hochschule Geisenheim University, 65366, Geisenheim, Germany
| | - M Rob G Roelfsema
- Molecular Plant Physiology and Biophysics, Biocenter, University of Würzburg, 97082, Würzburg, Germany
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Idzhilova OS, Smirnova GR, Petrovskaya LE, Kolotova DA, Ostrovsky MA, Malyshev AY. Cationic Channelrhodopsin from the Alga Platymonas subcordiformis as a Promising Optogenetic Tool. Biochemistry (Mosc) 2022; 87:1327-1334. [PMID: 36509722 DOI: 10.1134/s0006297922110116] [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] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The progress in optogenetics largely depends on the development of light-activated proteins as new molecular tools. Using cultured hippocampal neurons, we compared the properties of two light-activated cation channels - classical channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2) and recently described channelrhodopsin isolated from the alga Platymonas subcordiformis (PsChR2). PsChR2 ensured generation of action potentials by neurons when activated by the pulsed light stimulation with the frequencies up to 40-50 Hz, while the upper limit for CrChR2 was 20-30 Hz. An important advantage of PsChR2 compared to classical channelrhodopsin CrChR2 is the blue shift of its excitation spectrum, which opens the possibility for its application in all-optical electrophysiology experiments that require the separation of the maxima of the spectra of channelrhodopsins used for the stimulation of neurons and the maxima of the excitation spectra of various red fluorescent probes. We compared the response (generation of action potentials) of neurons expressing CrChR2 and PsChR2 to light stimuli at 530 and 550 nm commonly used for the excitation of red fluorescent probes. The 530-nm light was significantly (3.7 times) less efficient in the activation of neurons expressing PsChR2 vs. CrChR2-expressing neurons. The light at 550 nm, even at the maximal used intensity, failed to stimulate neurons expressing either of the studied opsins. This indicates that the PsChR2 channelrhodopsin from the alga P. subcordiformis is a promising optogenetic tool, both in terms of its frequency characteristics and possibility of its application for neuronal stimulation with a short-wavelength (blue, 470 nm) light accompanied by simultaneous recording of various physiological processes using fluorescent probes.
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Affiliation(s)
- Olga S Idzhilova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, 117485, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Gulnur R Smirnova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, 117485, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Lada E Petrovskaya
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Darya A Kolotova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, 117485, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Mikhail A Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Alexey Y Malyshev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, 117485, Russia.
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14
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vom Dahl C, Müller CE, Berisha X, Nagel G, Zimmer T. Coupling the Cardiac Voltage-Gated Sodium Channel to Channelrhodopsin-2 Generates Novel Optical Switches for Action Potential Studies. Membranes (Basel) 2022; 12:907. [PMID: 36295666 PMCID: PMC9607247 DOI: 10.3390/membranes12100907] [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] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
Voltage-gated sodium (Na+) channels respond to short membrane depolarization with conformational changes leading to pore opening, Na+ influx, and action potential (AP) upstroke. In the present study, we coupled channelrhodopsin-2 (ChR2), the key ion channel in optogenetics, directly to the cardiac voltage-gated Na+ channel (Nav1.5). Fusion constructs were expressed in Xenopus laevis oocytes, and electrophysiological recordings were performed by the two-microelectrode technique. Heteromeric channels retained both typical Nav1.5 kinetics and light-sensitive ChR2 properties. Switching to the current-clamp mode and applying short blue-light pulses resulted either in subthreshold depolarization or in a rapid change of membrane polarity typically seen in APs of excitable cells. To study the effect of individual K+ channels on the AP shape, we co-expressed either Kv1.2 or hERG with one of the Nav1.5-ChR2 fusions. As expected, both delayed rectifier K+ channels shortened AP duration significantly. Kv1.2 currents remarkably accelerated initial repolarization, whereas hERG channel activity efficiently restored the resting membrane potential. Finally, we investigated the effect of the LQT3 deletion mutant ΔKPQ on the AP shape and noticed an extremely prolonged AP duration that was directly correlated to the size of the non-inactivating Na+ current fraction. In conclusion, coupling of ChR2 to a voltage-gated Na+ channel generates optical switches that are useful for studying the effect of individual ion channels on the AP shape. Moreover, our novel optogenetic approach provides the potential for an application in pharmacology and optogenetic tissue-engineering.
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Affiliation(s)
- Christian vom Dahl
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, 07740 Jena, Germany
| | - Christoph Emanuel Müller
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, 07740 Jena, Germany
| | - Xhevat Berisha
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, 07740 Jena, Germany
| | - Georg Nagel
- Institute of Physiology—Neurophysiology, Julius Maximilians University, 97070 Wuerzburg, Germany
| | - Thomas Zimmer
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, 07740 Jena, Germany
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15
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Pyari G, Bansal H, Roy S. Ultra-low power deep sustained optogenetic excitation of human ventricular cardiomyocytes with red-shifted opsins: A computational study. J Physiol 2022; 600:4653-4676. [PMID: 36068951 DOI: 10.1113/jp283366] [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: 05/25/2022] [Accepted: 08/31/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Formulation of accurate theoretical models of optogenetic control of HVCMs expressed with newly-discovered opsins (ChRmine, bReaChES, and CsChrimson). Under continuous illumination, action potentials in each opsin-expressing HVCMs can only be evoked in a certain range of irradiances. Action potentials in ChRmine-expressing HVCMs can be triggered at ultra-low power (6 μW/mm2 at 10 ms pulse or 0.7 μW/mm2 at 100 ms pulse at 585 nm), which is 2-3 orders of magnitude lower than reported results. Ongoing APs in ChRmine-expressing HVCMs can be suppressed by continuous illumination of 585 nm light at 2 μW/mm2 . ChRmine enables sustained excitation due to its faster recovery from the desensitized state. Optogenetic excitation of deeply situated cardiac cells is possible upto ∼ 7.46 mm and 10.2 mm with ChRmine on illuminating the outer surface of pericardium at safe irradiance at 585 nm and 650 nm, respectively. The study opens up prospects for designing energy-efficient light-induced pacemakers, resynchronization, and termination of ventricular tachycardia. ABSTRACT The main challenge in cardiac optogenetics is to have low-power, high-fidelity, and deep excitation of cells with minimal invasiveness and heating. We present a detailed computational study of optogenetic excitation of human ventricular cardiomyocytes (HVCMs) with new ChRmine, bReaChES and CsChrimson red-shifted opsins to overcome the challenge. Action potentials (APs) in ChRmine expressing HVCMs can be triggered at 6 μW/mm2 (10 ms pulse) and 0.7 μW/mm2 (100 ms pulse) at 585 nm which are two orders of magnitude lower than ChR2(H134R). This enables safe sustained excitation of deeply situated cardiac cells with ChRmine (7.46 mm) and with bReaChES (6.21 mm) with the light source at the pericardium surface. Deeper excitation upto 10.2 mm can be achieved with ChRmine by illuminating at 650 nm. Photostimulation conditions for minimum charge transfer during AP have been determined, which are important for tissue health under sustained excitation. The action potential duration for all the opsins is constant upto 100 ms pulse-width but increases thereafter. Interestingly, the AP frequency increases with irradiance under continuous illumination, which gets suppressed at higher irradiances. Optimal range of irradiance for each opsin to excite HVCMs has been determined. Under optimal photostimulation conditions, each opsin can precisely excite APs up to 2.5 Hz, while latency and power of light pulse for each AP in a sequence remain most stable and an order lower respectively, in ChRmine-expressing HVCMs. The study highlights the importance of ChRmine and bReaChES for resynchronization, termination of ventricular tachycardia, and designing optogenetic cardiac pacemakers with enhanced battery life. Abstract figure legend Deep optogenetic excitation of opsin-expressing cardiomyocytes by placing the light source (maximum output 5.5 mW/mm2 ) at the outer surface of the pericardium. Excitation of cardiomyocytes upto 10.2 mm (at 650 nm) and 7.46 mm (at 585 nm) is possible with ChRmine. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Gur Pyari
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, INDIA
| | - Himanshu Bansal
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, INDIA
| | - Sukhdev Roy
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, INDIA
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16
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Islam MT, Rumpf F, Tsuno Y, Kodani S, Sakurai T, Matsui A, Maejima T, Mieda M. Vasopressin neurons in the paraventricular hypothalamus promote wakefulness via lateral hypothalamic orexin neurons. Curr Biol 2022; 32:3871-3885.e4. [PMID: 35907397 DOI: 10.1016/j.cub.2022.07.020] [Citation(s) in RCA: 1] [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: 10/27/2021] [Revised: 06/11/2022] [Accepted: 07/08/2022] [Indexed: 01/25/2023]
Abstract
The sleep-wakefulness cycle is regulated by complicated neural networks that include many different populations of neurons throughout the brain. Arginine vasopressin neurons in the paraventricular nucleus of the hypothalamus (PVHAVP) regulate various physiological events and behaviors, such as body-fluid homeostasis, blood pressure, stress response, social interaction, and feeding. Changes in arousal level often accompany these PVHAVP-mediated adaptive responses. However, the contribution of PVHAVP neurons to sleep-wakefulness regulation has remained unknown. Here, we report the involvement of PVHAVP neurons in arousal promotion. Optogenetic stimulation of PVHAVP neurons rapidly induced transitions to wakefulness from both NREM and REM sleep. This arousal effect was dependent on AVP expression in these neurons. Similarly, chemogenetic activation of PVHAVP neurons increased wakefulness and reduced NREM and REM sleep, whereas chemogenetic inhibition of these neurons significantly reduced wakefulness and increased NREM sleep. We observed dense projections of PVHAVP neurons in the lateral hypothalamus with potential connections to orexin/hypocretin (LHOrx) neurons. Optogenetic stimulation of PVHAVP neuronal fibers in the LH immediately induced wakefulness, whereas blocking orexin receptors attenuated the arousal effect of PVHAVP neuronal activation drastically. Monosynaptic rabies-virus tracing revealed that PVHAVP neurons receive inputs from multiple brain regions involved in sleep-wakefulness regulation, as well as those involved in stress response and energy metabolism. Moreover, PVHAVP neurons mediated the arousal induced by novelty stress and a melanocortin receptor agonist melanotan-II. Thus, our data suggested that PVHAVP neurons promote wakefulness via LHOrx neurons in the basal sleep-wakefulness and some stressful conditions.
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Affiliation(s)
- Md Tarikul Islam
- Department of Integrative Neurophysiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan
| | - Florian Rumpf
- Department of Integrative Neurophysiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan; Graduate School of Life Sciences, University of Würzburg, Beatrice-Edgell-Weg 21, 97074 Würzburg, Germany
| | - Yusuke Tsuno
- Department of Integrative Neurophysiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan
| | - Shota Kodani
- Department of Integrative Neurophysiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan
| | - Takeshi Sakurai
- Faculty of Medicine/WPI-IIIS, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Ayako Matsui
- Department of Integrative Neurophysiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan
| | - Takashi Maejima
- Department of Integrative Neurophysiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan
| | - Michihiro Mieda
- Department of Integrative Neurophysiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan.
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17
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Junge S, Schmieder F, Sasse P, Czarske J, Torres-Mapa ML, Heisterkamp A. Holographic optogenetic stimulation with calcium imaging as an all optical tool for cardiac electrophysiology. J Biophotonics 2022; 15:e202100352. [PMID: 35397155 DOI: 10.1002/jbio.202100352] [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] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/25/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
All optical approaches to control and read out the electrical activity in a cardiac syncytium can improve our understanding of cardiac electrophysiology. Here, we demonstrate optogenetic stimulation of cardiomyocytes with high spatial precision using light foci generated with a ferroelectric spatial light modulator. Computer generated holograms binarized by bidirectional error diffusion create multiple foci with more even intensity distribution compared with thresholding approach. We evoke the electrical activity of cardiac HL1 cells expressing the channelrhodopsin-2 variant, ChR2(H134R) using single and multiple light foci and at the same time visualize the action potential using a calcium sensitive indicator called Cal-630. We show that localized regions in the cardiac monolayer can be stimulated enabling us to initiate signal propagation from a precise location. Furthermore, we demonstrate that probing the cardiac cells with multiple light foci enhances the excitability of the cardiac network. This approach opens new applications in manipulating and visualizing the electrical activity in a cardiac syncytium.
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Affiliation(s)
- Sebastian Junge
- Institute of Quantum Optics, Gottfried Wilhelm Leibniz University, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Felix Schmieder
- Faculty of Electrical and Computer Engineering, Laboratory of Measurement and Sensor System Technique and Competence Center Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Dresden, Germany
| | - Philipp Sasse
- Medical Faculty, Institute of Physiology I, University of Bonn, Bonn, Germany
| | - Jürgen Czarske
- Faculty of Electrical and Computer Engineering, Laboratory of Measurement and Sensor System Technique and Competence Center Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Dresden, Germany
- Faculty of Physics, School of Science and Excellence Cluster Physics of Life, TU Dresden, Dresden, Germany
| | - Maria Leilani Torres-Mapa
- Institute of Quantum Optics, Gottfried Wilhelm Leibniz University, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Alexander Heisterkamp
- Institute of Quantum Optics, Gottfried Wilhelm Leibniz University, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
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18
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Baleisyte A, Schneggenburger R, Kochubey O. Stimulation of medial amygdala GABA neurons with kinetically different channelrhodopsins yields opposite behavioral outcomes. Cell Rep 2022; 39:110850. [PMID: 35613578 DOI: 10.1016/j.celrep.2022.110850] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [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: 09/13/2021] [Revised: 12/20/2021] [Accepted: 04/30/2022] [Indexed: 12/11/2022] Open
Abstract
The medial amygdala (MeA) receives pheromone information about conspecifics and has crucial functions in social behaviors. A previous study showed that activation of GABA neurons in the postero-dorsal MeA (MeApd) with channelrhodopsin-2H134R (ChR2) stimulates inter-male aggression. When performing these experiments using the faster channelrhodopsinH134R,E123T (ChETA), we find the opposite behavioral outcome. A systematic comparison between the two channelrhodopsin variants reveals that optogenetic activation of MeApd GABA neurons with ChETA suppresses aggression, whereas activation under ChR2 increases aggression. Although the mechanism for this paradoxical difference is not understood, we observe that activation of MeApd GABA neurons with ChR2 causes larger plateau depolarizations, smaller action potentials, and larger local inhibition than with ChETA. Thus, the channelrhodopsin variant used for in vivo optogenetic experiments can radically influence the behavioral outcome. Future work should continue to study the role of specific sub-populations of MeApd GABA neurons in aggression control.
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Affiliation(s)
- Aiste Baleisyte
- Laboratory of Synaptic Mechanisms, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ralf Schneggenburger
- Laboratory of Synaptic Mechanisms, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Olexiy Kochubey
- Laboratory of Synaptic Mechanisms, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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19
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Balmer TS, Trussell LO. Descending Axonal Projections from the Inferior Colliculus Target Nearly All Excitatory and Inhibitory Cell Types of the Dorsal Cochlear Nucleus. J Neurosci 2022; 42:3381-3393. [PMID: 35273085 PMCID: PMC9034789 DOI: 10.1523/jneurosci.1190-21.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [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] [Received: 06/09/2021] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 11/21/2022] Open
Abstract
The dorsal cochlear nucleus (DCN) integrates auditory nerve input with nonauditory sensory signals and is proposed to function in sound source localization and suppression of self-generated sounds. The DCN also integrates activity from descending auditory pathways, including a particularly large feedback projection from the inferior colliculus (IC), the main ascending target of the DCN. Understanding how these descending feedback signals are integrated into the DCN circuit and what role they play in hearing requires knowing the targeted DCN cell types and their postsynaptic responses. In order to explore these questions, neurons in the DCN that received descending synaptic input from the IC were labeled with a trans-synaptic viral approach in male and female mice, which allowed them to be targeted for whole-cell recording in acute brain slices. We tested their synaptic responses to optogenetic activation of the descending IC projection. Every cell type in the granule cell domain received monosynaptic, glutamatergic input from the IC, indicating that this region, considered an integrator of nonauditory sensory inputs, processes auditory input as well and may have complex and underappreciated roles in hearing. Additionally, we found that DCN cell types outside the granule cell regions also receive descending IC signals, including the principal projection neurons, as well as the neurons that inhibit them, leading to a circuit that may sharpen tuning through feedback excitation and lateral inhibition.SIGNIFICANCE STATEMENT Auditory processing starts in the cochlea and ascends through the dorsal cochlear nucleus (DCN) to the inferior colliculus (IC) and beyond. Here, we investigated the feedback projection from IC to DCN, whose synaptic targets and roles in auditory processing are unclear. We found that all cell types in the granule cell regions, which process multisensory feedback, also process this descending auditory feedback. Surprisingly, all except one cell type in the entire DCN receive IC input. The IC-DCN projection may therefore modulate the multisensory pathway as well as sharpen tuning and gate auditory signals that are sent to downstream areas. This excitatory feedback loop from DCN to IC and back to DCN could underlie hyperexcitability in DCN, widely considered an etiology of tinnitus.
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Affiliation(s)
- Timothy S Balmer
- Vollum Institute and Oregon Hearing Research Center, Oregon Health & Science University, Portland, Oregon 97239
| | - Laurence O Trussell
- Vollum Institute and Oregon Hearing Research Center, Oregon Health & Science University, Portland, Oregon 97239
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20
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Kishi KE, Kim YS, Fukuda M, Inoue M, Kusakizako T, Wang PY, Ramakrishnan C, Byrne EFX, Thadhani E, Paggi JM, Matsui TE, Yamashita K, Nagata T, Konno M, Quirin S, Lo M, Benster T, Uemura T, Liu K, Shibata M, Nomura N, Iwata S, Nureki O, Dror RO, Inoue K, Deisseroth K, Kato HE. Structural basis for channel conduction in the pump-like channelrhodopsin ChRmine. Cell 2022; 185:672-689.e23. [PMID: 35114111 PMCID: PMC7612760 DOI: 10.1016/j.cell.2022.01.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [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] [Received: 10/31/2021] [Revised: 12/13/2021] [Accepted: 01/11/2022] [Indexed: 12/24/2022]
Abstract
ChRmine, a recently discovered pump-like cation-conducting channelrhodopsin, exhibits puzzling properties (large photocurrents, red-shifted spectrum, and extreme light sensitivity) that have created new opportunities in optogenetics. ChRmine and its homologs function as ion channels but, by primary sequence, more closely resemble ion pump rhodopsins; mechanisms for passive channel conduction in this family have remained mysterious. Here, we present the 2.0 Å resolution cryo-EM structure of ChRmine, revealing architectural features atypical for channelrhodopsins: trimeric assembly, a short transmembrane-helix 3, a twisting extracellular-loop 1, large vestibules within the monomer, and an opening at the trimer interface. We applied this structure to design three proteins (rsChRmine and hsChRmine, conferring further red-shifted and high-speed properties, respectively, and frChRmine, combining faster and more red-shifted performance) suitable for fundamental neuroscience opportunities. These results illuminate the conduction and gating of pump-like channelrhodopsins and point the way toward further structure-guided creation of channelrhodopsins for applications across biology.
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Affiliation(s)
- Koichiro E Kishi
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Yoon Seok Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Masahiro Fukuda
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Masatoshi Inoue
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Peter Y Wang
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | | | - Eamon F X Byrne
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Elina Thadhani
- Department of Bioengineering, Stanford University, Stanford, CA, USA; Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Joseph M Paggi
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Toshiki E Matsui
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Keitaro Yamashita
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Takashi Nagata
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Masae Konno
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Sean Quirin
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Maisie Lo
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Tyler Benster
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Tomoko Uemura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan
| | - Kehong Liu
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan
| | - Mikihiro Shibata
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma, Kanazawa, Japan; High-Speed AFM for Biological Application Unit, Institute for Frontier Science Initiative, Kanazawa University, Kakuma, Kanazawa, Japan
| | - Norimichi Nomura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan
| | - So Iwata
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan; RIKEN SPring-8 Center, Kouto, Sayo-cho, Sayo-gun, Hyogo, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Ron O Dror
- Department of Computer Science, Stanford University, Stanford, CA, USA; Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Keiichi Inoue
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, USA; CNC Program, Stanford University, Palo Alto, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA; Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA.
| | - Hideaki E Kato
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan; FOREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan.
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21
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Grimes WN, Sedlacek M, Musgrove M, Nath A, Tian H, Hoon M, Rieke F, Singer JH, Diamond JS. Dendro-somatic synaptic inputs to ganglion cells contradict receptive field and connectivity conventions in the mammalian retina. Curr Biol 2022; 32:315-328.e4. [PMID: 34822767 DOI: 10.1016/j.cub.2021.11.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/08/2021] [Accepted: 11/02/2021] [Indexed: 01/26/2023]
Abstract
The morphology of retinal neurons strongly influences their physiological function. Ganglion cell (GC) dendrites ramify in distinct strata of the inner plexiform layer (IPL) so that GCs responding to light increments (ON) or decrements (OFF) receive appropriate excitatory inputs. This vertical stratification prescribes response polarity and ensures consistent connectivity between cell types, whereas the lateral extent of GC dendritic arbors typically dictates receptive field (RF) size. Here, we identify circuitry in mouse retina that contradicts these conventions. AII amacrine cells are interneurons understood to mediate "crossover" inhibition by relaying excitatory input from the ON layer to inhibitory outputs in the OFF layer. Ultrastructural and physiological analyses show, however, that some AIIs deliver powerful inhibition to OFF GC somas and proximal dendrites in the ON layer, rendering the inhibitory RFs of these GCs smaller than their dendritic arbors. This OFF pathway, avoiding entirely the OFF region of the IPL, challenges several tenets of retinal circuitry. These results also indicate that subcellular synaptic organization can vary within a single population of neurons according to their proximity to potential postsynaptic targets.
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Wright P, Rodgers J, Wynne J, Bishop PN, Lucas RJ, Milosavljevic N. Viral Transduction of Human Rod Opsin or Channelrhodopsin Variants to Mouse ON Bipolar Cells Does Not Impact Retinal Anatomy or Cause Measurable Death in the Targeted Cells. Int J Mol Sci 2021; 22:ijms222313111. [PMID: 34884916 PMCID: PMC8658283 DOI: 10.3390/ijms222313111] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/26/2021] [Accepted: 12/01/2021] [Indexed: 11/16/2022] Open
Abstract
The viral gene delivery of optogenetic actuators to the surviving inner retina has been proposed as a strategy for restoring vision in advanced retinal degeneration. We investigated the safety of ectopic expression of human rod opsin (hRHO), and two channelrhodopsins (enhanced sensitivity CoChR-3M and red-shifted ReaChR) by viral gene delivery in ON bipolar cells of the mouse retina. Adult Grm6Cre mice were bred to be retinally degenerate or non-retinally degenerate (homozygous and heterozygous for the rd1Pde6b mutation, respectively) and intravitreally injected with recombinant adeno-associated virus AAV2/2(quad Y-F) serotype containing a double-floxed inverted transgene comprising one of the opsins of interest under a CMV promoter. None of the opsins investigated caused changes in retinal thickness; induced apoptosis in the retina or in transgene expressing cells; or reduced expression of PKCα (a specific bipolar cell marker). No increase in retinal inflammation at the level of gene expression (IBA1/AIF1) was found within the treated mice compared to controls. The expression of hRHO, CoChR or ReaChR under a strong constitutive promoter in retinal ON bipolar cells following intravitreal delivery via AAV2 does not cause either gross changes in retinal health, or have a measurable impact on the survival of targeted cells.
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23
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Kolesov DV, Sokolinskaya EL, Lukyanov KA, Bogdanov AM. Molecular Tools for Targeted Control of Nerve Cell Electrical Activity. Part II. Acta Naturae 2021; 13:17-32. [PMID: 35127143 PMCID: PMC8807539 DOI: 10.32607/actanaturae.11415] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 08/24/2020] [Accepted: 05/14/2021] [Indexed: 01/01/2023] Open
Abstract
In modern life sciences, the issue of a specific, exogenously directed manipulation of a cell's biochemistry is a highly topical one. In the case of electrically excitable cells, the aim of the manipulation is to control the cells' electrical activity, with the result being either excitation with subsequent generation of an action potential or inhibition and suppression of the excitatory currents. The techniques of electrical activity stimulation are of particular significance in tackling the most challenging basic problem: figuring out how the nervous system of higher multicellular organisms functions. At this juncture, when neuroscience is gradually abandoning the reductionist approach in favor of the direct investigation of complex neuronal systems, minimally invasive methods for brain tissue stimulation are becoming the basic element in the toolbox of those involved in the field. In this review, we describe three approaches that are based on the delivery of exogenous, genetically encoded molecules sensitive to external stimuli into the nervous tissue. These approaches include optogenetics (overviewed in Part I), as well as chemogenetics and thermogenetics (described here, in Part II), which is significantly different not only in the nature of the stimuli and structure of the appropriate effector proteins, but also in the details of experimental applications. The latter circumstance is an indication that these are rather complementary than competing techniques.
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Affiliation(s)
- D. V. Kolesov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997 Russia
| | - E. L. Sokolinskaya
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997 Russia
| | - K. A. Lukyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997 Russia
| | - A. M. Bogdanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997 Russia
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24
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Najjar SA, Edwards BS, Albers KM, Davis BM, Smith-Edwards KM. Optogenetic activation of the distal colon epithelium engages enteric nervous system circuits to initiate motility patterns. Am J Physiol Gastrointest Liver Physiol 2021; 321:G426-G435. [PMID: 34468219 PMCID: PMC8560371 DOI: 10.1152/ajpgi.00026.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 08/18/2021] [Accepted: 08/23/2021] [Indexed: 02/07/2023]
Abstract
Digestive functions of the colon depend on sensory-motor reflexes in the enteric nervous system (ENS), initiated by intrinsic primary afferent neurons (IPANs). IPAN terminals project to the mucosal layer of the colon, allowing communication with epithelial cells comprising the colon lining. The chemical nature and functional significance of this epithelial-neural communication in regard to secretion and colon motility are of high interest. Colon epithelial cells can produce and release neuroactive substances such as ATP and 5-hydroxytryptamine (5-HT), which can activate receptors on adjacent nerve fibers, including IPAN subtypes. In this study, we examined if stimulation of epithelial cells alone is sufficient to activate neural circuits that control colon motility. Optogenetics and calcium imaging were used in ex vivo preparations of the mouse colon to selectively stimulate the colon epithelium, measure changes in motility, and record activity of neurons within the myenteric plexus. Light-mediated activation of epithelial cells lining the distal, but not proximal, colon caused local contractions and increased the rate of colonic migrating motor complexes. Epithelial-evoked local contractions in the distal colon were reduced by both ATP and 5-HT receptor antagonists. Our findings indicate that colon epithelial cells likely use purinergic and serotonergic signaling to initiate activity in myenteric neurons, produce local contractions, and facilitate large-scale coordination of ENS activity responsible for whole colon motility patterns.NEW & NOTEWORTHY Using an all-optical approach to measure real-time cell-to-cell communication responsible for colon functions, we show that selective optogenetic stimulation of distal colon epithelium produced activity in myenteric neurons, as measured with red genetically encoded calcium indicators. The epithelial-induced neural response led to local contractions, mediated by both purinergic and serotonergic signaling, and facilitated colonic motor complexes that propagate from proximal to distal colon.
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Affiliation(s)
- Sarah A Najjar
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, Pennsylvania
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Brian S Edwards
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, Pennsylvania
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Kathryn M Albers
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, Pennsylvania
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Brian M Davis
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, Pennsylvania
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Kristen M Smith-Edwards
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, Pennsylvania
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
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25
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Martinetti LE, Bonekamp KE, Autio DM, Kim HH, Crandall SR. Short-Term Facilitation of Long-Range Corticocortical Synapses Revealed by Selective Optical Stimulation. Cereb Cortex 2021; 32:1932-1949. [PMID: 34519352 PMCID: PMC9070351 DOI: 10.1093/cercor/bhab325] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 11/14/2022] Open
Abstract
Short-term plasticity regulates the strength of central synapses as a function of previous activity. In the neocortex, direct synaptic interactions between areas play a central role in cognitive function, but the activity-dependent regulation of these long-range corticocortical connections and their impact on a postsynaptic target neuron is unclear. Here, we use an optogenetic strategy to study the connections between mouse primary somatosensory and motor cortex. We found that short-term facilitation was strong in both corticocortical synapses, resulting in far more sustained responses than local intracortical and thalamocortical connections. A major difference between pathways was that the synaptic strength and magnitude of facilitation were distinct for individual excitatory cells located across all cortical layers and specific subtypes of GABAergic neurons. Facilitation was dependent on the presynaptic calcium sensor synaptotagmin-7 and altered by several optogenetic approaches. Current-clamp recordings revealed that during repetitive activation, the short-term dynamics of corticocortical synapses enhanced the excitability of layer 2/3 pyramidal neurons, increasing the probability of spiking with activity. Furthermore, the properties of the connections linking primary with secondary somatosensory cortex resemble those between somatosensory-motor areas. These short-term changes in transmission properties suggest long-range corticocortical synapses are specialized for conveying information over relatively extended periods.
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Affiliation(s)
| | | | - Dawn M Autio
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Hye-Hyun Kim
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
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26
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Chang CC, Chong HT, Tashiro 田代 歩 A. Laser Capture Microdissection of Single Neurons with Morphological Visualization Using Fluorescent Proteins Fused to Transmembrane Proteins. eNeuro 2021; 8:ENEURO. [PMID: 34400471 DOI: 10.1523/ENEURO.0275-20.2021] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/12/2021] [Accepted: 07/15/2021] [Indexed: 11/23/2022] Open
Abstract
Gene expression analysis in individual neuronal types helps in understanding brain function. Genetic methods expressing fluorescent proteins are widely used to label specific neuronal populations. However, because cell type specificity of genetic labeling is often limited, it is advantageous to combine genetic labeling with additional methods to select specific cell/neuronal types. Laser capture microdissection is one of such techniques with which one can select a specific cell/neuronal population based on morphological observation. However, a major issue is the disappearance of fluorescence signals during the tissue processing that is required for high-quality sample preparation. Here, we developed a simple, novel method in which fluorescence signals are preserved. We use genetic labeling with fluorescence proteins fused to transmembrane proteins, which shows highly stable fluorescence retention and allows for the selection of fluorescent neurons/cells based on morphology. Using this method in mice, we laser-captured neuronal somata and successfully isolated RNA. We determined that ∼100 cells are sufficient to obtain a sample required for downstream applications such as quantitative PCR. Capability to specifically microdissect targeted neurons was demonstrated by an ∼10-fold increase in mRNA for fluorescent proteins in visually identified neurons expressing the fluorescent proteins compared with neighboring cells not expressing it. We applied this method to validate virus-mediated single-cell knockout, which showed up to 92% reduction in knocked-out gene RNA compared with wild-type neurons. This method using fluorescent proteins fused to transmembrane proteins provides a new, simple solution to perform gene expression analysis in sparsely labeled neuronal/cellular populations, which is especially advantageous when genetic labeling has limited specificity.
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Wicker E, Forcelli PA. Optogenetic activation of the reticular nucleus of the thalamus attenuates limbic seizures via inhibition of the midline thalamus. Epilepsia 2021; 62:2283-2296. [PMID: 34309008 PMCID: PMC9092275 DOI: 10.1111/epi.17016] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 01/21/2023]
Abstract
OBJECTIVE The nucleus reticularis of the thalamus (nRT) is most studied in epilepsy for its role in the genesis of absence seizures; much less is known regarding its role in other seizure types, including those originating in limbic structures and the temporal lobe. As it is a major source of inhibitory input to higher order thalamic nuclei, stimulation of the nRT may be an effective strategy to disrupt seizure activity that requires thalamic engagement. METHODS We recorded single unit activity from the nRT prior to and after infusion of bicuculline into the area tempestas. We monitored single unit activity time-locked with interictal spikes. We optogenetically activated the nRT in both the area tempestas and amygdala kindling models. We tested a role for projections from the nRT to higher order midline thalamic nuclei through the use of retrogradely trafficked viral vector. RESULTS Mean firing rate in the nRT was decreased after infusion of bicuculline into the area tempestas as compared to the preinfusion baseline. nRT unit firing in response to interictal spikes was heterogeneous, with an approximately equal proportion of neurons displaying (1) no change in firing, (2) increased firing, and (3) decreasing firing. Optogenetic activation of the nRT significantly suppressed seizure activity in both the area tempestas and amygdala kindling models. Optogenetic activation of contralaterally targeting projections but not ipsilaterally targeting projections from the nRT to the midline thalamus significantly suppressed seizures in the kindling model. SIGNIFICANCE Although the nRT is typically thought of in the context of absence seizures, our data show that it may be a viable target for other seizure types. In two models that recapitulate the seizure types seen in temporal lobe epilepsy, nRT activation suppressed both electrographic and behavioral seizures. These data suggest that the nRT should be considered more broadly in the context of epilepsy.
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Affiliation(s)
- Evan Wicker
- Department of Pharmacology & Physiology, Georgetown University, Washington DC, USA
| | - Patrick A. Forcelli
- Department of Pharmacology & Physiology, Georgetown University, Washington DC, USA
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington DC, USA
- Department of Neuroscience, Georgetown University, Washington DC, USA
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28
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Becker-Baldus J, Leeder A, Brown LJ, Brown RCD, Bamann C, Glaubitz C. The Desensitized Channelrhodopsin-2 Photointermediate Contains 13 -cis, 15 -syn Retinal Schiff Base. Angew Chem Int Ed Engl 2021; 60:16442-16447. [PMID: 33973334 PMCID: PMC8362212 DOI: 10.1002/anie.202015797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 11/26/2020] [Revised: 03/18/2021] [Indexed: 11/13/2022]
Abstract
Channelrhodopsin‐2 (ChR2) is a light‐gated cation channel and was used to lay the foundations of optogenetics. Its dark state X‐ray structure has been determined in 2017 for the wild‐type, which is the prototype for all other ChR variants. However, the mechanistic understanding of the channel function is still incomplete in terms of structural changes after photon absorption by the retinal chromophore and in the framework of functional models. Hence, detailed information needs to be collected on the dark state as well as on the different photointermediates. For ChR2 detailed knowledge on the chromophore configuration in the different states is still missing and a consensus has not been achieved. Using DNP‐enhanced solid‐state MAS NMR spectroscopy on proteoliposome samples, we unambiguously determined the chromophore configuration in the desensitized state, and we show that this state occurs towards the end of the photocycle.
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Affiliation(s)
- Johanna Becker-Baldus
- Institute of Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Alexander Leeder
- Department of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Lynda J Brown
- Department of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Richard C D Brown
- Department of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Christian Bamann
- Max-Planck-Institute of Biophysics, Max-von-Laue-Str. 3, 60438, Frankfurt, Germany
| | - Clemens Glaubitz
- Institute of Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438, Frankfurt, Germany
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29
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Castillo-Ocampo Y, Colón M, Hernández A, Lopez P, Gerena Y, Porter JT. Plasticity of GluN1 at Ventral Hippocampal Synapses in the Infralimbic Cortex. Front Synaptic Neurosci 2021; 13:695964. [PMID: 34335223 PMCID: PMC8320376 DOI: 10.3389/fnsyn.2021.695964] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/25/2021] [Indexed: 11/25/2022] Open
Abstract
Although the infralimbic cortex (IL) is not thought to play a role in fear acquisition, recent experiments found evidence that synaptic plasticity is occurring at ventral hippocampal (vHPC) synapses in IL during auditory fear acquisition as measured by changes in the N-methyl-D-aspartate (NMDA) receptor-mediated currents in male rats. These electrophysiological data suggest that fear conditioning changes the expression of NMDA receptors on vHPC-to-IL synapses. To further evaluate the plasticity of NMDA receptors at this specific synapse, we injected AAV particles expressing channelrhodopsin-EYFP into the vHPC of male and female rats to label vHPC projections with EYFP. To test for NMDA receptor changes in vHPC-to-IL synapses after fear learning, we used fluorescence-activated cell sorting (FACS) to quantify synaptosomes isolated from IL tissue punches that were positive for EYFP and the obligatory GluN1 subunit. More EYFP+/GluN1+ synaptosomes with greater average expression of GluN1 were isolated from male rats exposed to auditory fear conditioning (AFC) than those exposed to context and tones only or to contextual fear conditioning (CFC), suggesting that AFC increased NMDA receptor expression in males. In a second experiment, we found that pairing the tones and shocks was required to induce the molecular changes and that fear extinction did not reverse the changes. In contrast, females showed similar levels of EYFP+/GluN1+ synaptosomes in all behavioral groups. These findings suggest that AFC induces synaptic plasticity of NMDA receptors in the vHPC-to-IL projection in males, while female rats rely on different synaptic mechanisms.
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Affiliation(s)
- Yesenia Castillo-Ocampo
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, Puerto Rico
| | - María Colón
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, Puerto Rico
| | - Anixa Hernández
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, Puerto Rico
| | - Pablo Lopez
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, Puerto Rico
| | - Yamil Gerena
- Department of Pharmacology and Toxicology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - James T Porter
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, Puerto Rico
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30
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Rokitskaya TI, Maliar N, Kovalev KV, Volkov O, Gordeliy VI, Antonenko YN. Rhodopsin Channel Activity Can Be Evaluated by Measuring the Photocurrent Voltage Dependence in Planar Bilayer Lipid Membranes. Biochemistry (Mosc) 2021; 86:409-419. [PMID: 33941063 DOI: 10.1134/s0006297921040039] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The studies of the functional properties of retinal-containing proteins often include experiments in model membrane systems, e.g., measurements of electric current through planar bilayer lipid membranes (BLMs) with proteoliposomes adsorbed on one of the membrane surfaces. However, the possibilities of this method have not been fully explored yet. We demonstrated that the voltage dependence of stationary photocurrents for two light-sensitive proteins, bacteriorhodopsin (bR) and channelrhodopsin 2 (ChR2), in the presence of protonophore had very different characteristics. In the case of the bR (proton pump), the photocurrent through the BLM did not change direction when the polarity of the applied voltage was switched. In the case of the photosensitive channel protein ChR2, the photocurrent increased with the increase in voltage and the current polarity changed with the change in the voltage polarity. The protonophore 4,5,6,7-tetrachloro-2-trifluoromethyl benzimidazole (TTFB) was more efficient in the maximizing stationary photocurrents. In the presence of carbonyl cyanide-m-chlorophenylhydrazone (CCCP), the amplitude of the measured photocurrents for bR significantly decreased, while in the case of ChR2, the photocurrents virtually disappeared. The difference between the effects of TTFB and CCCP was apparently due to the fact that, in contrast to TTFB, CCCP transfers protons across the liposome membranes with a higher rate than through the decane-containing BLM used as a surface for the proteoliposome adsorption.
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Affiliation(s)
- Tatyana I Rokitskaya
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
| | - Nina Maliar
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Kirill V Kovalev
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia.,Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, 38044, France
| | - Oleksandr Volkov
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Juelich, 52425, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Juelich, 52425, Germany
| | - Valentin I Gordeliy
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia.,Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, 38044, France.,Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Juelich, 52425, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Juelich, 52425, Germany
| | - Yuri N Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
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Abstract
Abdominal pain is common in patients with active inflammation of the colon but can persist even in its absence, suggesting other mechanisms of pain signaling. Recent findings suggest colon epithelial cells are direct regulators of pain-sensing neurons. Optogenetic activation of epithelial cells evoked nerve firing and pain-like behaviors. Inhibition of epithelial cells caused the opposite effect, reducing responses to colon distension and inflammatory hypersensitivity. Thus, epithelial cells alone can regulate the activation of pain circuits. Future goals are to define the anatomical and cellular mechanisms that underlie epithelial-neural pain signaling and how it is altered in response to colon inflammation.
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Affiliation(s)
- Sarah A Najjar
- Department of Neurobiology and Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA,Present address: Department of Pediatrics, Columbia University Medical Center, New York, New York, USA
| | - Kathryn M Albers
- Department of Neurobiology and Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA,Address correspondence to: Kathryn M. Albers, PhD, Department of Neurobiology, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15216, USA ()
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Jeong YM, Choi TI, Hwang KS, Lee JS, Gerlai R, Kim CH. Optogenetic Manipulation of Olfactory Responses in Transgenic Zebrafish: A Neurobiological and Behavioral Study. Int J Mol Sci 2021; 22:7191. [PMID: 34281244 DOI: 10.3390/ijms22137191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 07/01/2021] [Indexed: 11/18/2022] Open
Abstract
Olfaction is an important neural system for survival and fundamental behaviors such as predator avoidance, food finding, memory formation, reproduction, and social communication. However, the neural circuits and pathways associated with the olfactory system in various behaviors are not fully understood. Recent advances in optogenetics, high-resolution in vivo imaging, and reconstructions of neuronal circuits have created new opportunities to understand such neural circuits. Here, we generated a transgenic zebrafish to manipulate olfactory signal optically, expressing the Channelrhodopsin (ChR2) under the control of the olfactory specific promoter, omp. We observed light-induced neuronal activity of olfactory system in the transgenic fish by examining c-fos expression, and a calcium indicator suggesting that blue light stimulation caused activation of olfactory neurons in a non-invasive manner. To examine whether the photo-activation of olfactory sensory neurons affect behavior of zebrafish larvae, we devised a behavioral choice paradigm and tested how zebrafish larvae choose between two conflicting sensory cues, an aversive odor or the naturally preferred phototaxis. We found that when the conflicting cues (the preferred light and aversive odor) were presented together simultaneously, zebrafish larvae swam away from the aversive odor. However, the transgenic fish with photo-activation were insensitive to the aversive odor and exhibited olfactory desensitization upon optical stimulation of ChR2. These results show that an aversive olfactory stimulus can override phototaxis, and that olfaction is important in decision making in zebrafish. This new transgenic model will be useful for the analysis of olfaction related behaviors and for the dissection of underlying neural circuits.
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Tabata K, Sugano E, Hatakeyama A, Watanabe Y, Suzuki T, Ozaki T, Fukuda T, Tomita H. Phototoxicities Caused by Continuous Light Exposure Were Not Induced in Retinal Ganglion Cells Transduced by an Optogenetic Gene. Int J Mol Sci 2021; 22:6732. [PMID: 34201658 DOI: 10.3390/ijms22136732] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 11/16/2022] Open
Abstract
The death of photoreceptor cells is induced by continuous light exposure. However, it is unclear whether light damage was induced in retinal ganglion cells with photosensitivity by transduction of optogenetic genes. In this study, we evaluated the phototoxicities of continuous light exposure on retinal ganglion cells after transduction of the optogenetic gene mVChR1 using an adeno-associated virus vector. Rats were exposed to continuous light for a week, and visually evoked potentials (VEPs) were recorded. The intensities of continuous light (500, 1000, 3000, and 5000 lx) increased substantially after VEP recordings. After the final recording of VEPs, retinal ganglion cells (RGCs) were retrogradely labeled with a fluorescein tracer, FluoroGold, and the number of retinal ganglion cells was counted under a fluorescent microscope. There was no significant reduction in the amplitudes of VEPs and the number of RGCs after exposure to any light intensity. These results indicated that RGCs were photosensitive after the transduction of optogenetic genes and did not induce any phototoxicity by continuous light exposure.
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Jeon S, Lee Y, Ryu D, Cho YK, Lee Y, Jun SB, Ji CH. Implantable Optrode Array for Optogenetic Modulation and Electrical Neural Recording. Micromachines (Basel) 2021; 12:mi12060725. [PMID: 34205473 PMCID: PMC8234104 DOI: 10.3390/mi12060725] [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] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 02/06/2023]
Abstract
During the last decade, optogenetics has become an essential tool for neuroscience research due to its unrivaled feature of cell-type-specific neuromodulation. There have been several technological advances in light delivery devices. Among them, the combination of optogenetics and electrophysiology provides an opportunity for facilitating optogenetic approaches. In this study, a novel design of an optrode array was proposed for realizing optical modulation and electrophysiological recording. A 4 × 4 optrode array and five-channel recording electrodes were assembled as a disposable part, while a reusable part comprised an LED (light-emitting diode) source and a power line. After the characterization of the intensity of the light delivered at the fiber tips, in vivo animal experiment was performed with transgenic mice expressing channelrhodopsin, showing the effectiveness of optical activation and neural recording.
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Affiliation(s)
- Saeyeong Jeon
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea; (S.J.); (D.R.)
| | - Youjin Lee
- Department of Electronic and Electrical Engineering, Ewha Womans University, Seoul 03760, Korea; (Y.L.); (Y.K.C.); (Y.L.); (S.B.J.)
- Graduate Program in Smart Factory, Ewha Womans University, Seoul 03760, Korea
| | - Daeho Ryu
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea; (S.J.); (D.R.)
| | - Yoon Kyung Cho
- Department of Electronic and Electrical Engineering, Ewha Womans University, Seoul 03760, Korea; (Y.L.); (Y.K.C.); (Y.L.); (S.B.J.)
| | - Yena Lee
- Department of Electronic and Electrical Engineering, Ewha Womans University, Seoul 03760, Korea; (Y.L.); (Y.K.C.); (Y.L.); (S.B.J.)
| | - Sang Beom Jun
- Department of Electronic and Electrical Engineering, Ewha Womans University, Seoul 03760, Korea; (Y.L.); (Y.K.C.); (Y.L.); (S.B.J.)
- Graduate Program in Smart Factory, Ewha Womans University, Seoul 03760, Korea
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul 03760, Korea
| | - Chang-Hyeon Ji
- Department of Electronic and Electrical Engineering, Ewha Womans University, Seoul 03760, Korea; (Y.L.); (Y.K.C.); (Y.L.); (S.B.J.)
- Graduate Program in Smart Factory, Ewha Womans University, Seoul 03760, Korea
- Correspondence: ; Tel.: +82-2-3277-3895
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35
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Bali B, Lopez de la Morena D, Mittring A, Mager T, Rankovic V, Huet AT, Moser T. Utility of red-light ultrafast optogenetic stimulation of the auditory pathway. EMBO Mol Med 2021; 13:e13391. [PMID: 33960685 PMCID: PMC8185542 DOI: 10.15252/emmm.202013391] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 11/09/2022] Open
Abstract
Optogenetic stimulation of spiral ganglion neurons (SGNs) in the ear provides a future alternative to electrical stimulation used in current cochlear implants. Here, we employed fast and very fast variants of the red-light-activated channelrhodopsin (ChR) Chrimson (f-Chrimson and vf-Chrimson) to study their utility for optogenetic stimulation of SGNs in mice. The light requirements were higher for vf-Chrimson than for f-Chrimson, even when optimizing membrane expression of vf-Chrimson by adding potassium channel trafficking sequences. Optogenetic time and intensity coding by single putative SGNs were compared with coding of acoustic clicks. vf-Chrimson enabled putative SGNs to fire at near-physiological rates with good temporal precision up to 250 Hz of stimulation. The dynamic range of SGN spike rate coding upon optogenetic stimulation was narrower than for acoustic clicks but larger than reported for electrical stimulation. The dynamic range of spike timing, on the other hand, was more comparable for optogenetic and acoustic stimulation. In conclusion, f-Chrimson and vf-Chrimson are promising candidates for optogenetic stimulation of SGNs in auditory research and future cochlear implants.
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Affiliation(s)
- Burak Bali
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Göttingen Graduate School for Neurosciences and Molecular BiosciencesUniversity of GöttingenGöttingenGermany
- Restorative Cochlear Genomics GroupAuditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - David Lopez de la Morena
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Göttingen Graduate School for Neurosciences and Molecular BiosciencesUniversity of GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Auditory Neuroscience GroupMax‐Planck‐Institute for Experimental MedicineGöttingenGermany
| | - Artur Mittring
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Circuit LabInstitute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
| | - Thomas Mager
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC)University of GöttingenGöttingenGermany
| | - Vladan Rankovic
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Restorative Cochlear Genomics GroupAuditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Antoine Tarquin Huet
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Auditory Circuit LabInstitute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC)University of GöttingenGöttingenGermany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Auditory Neuroscience GroupMax‐Planck‐Institute for Experimental MedicineGöttingenGermany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC)University of GöttingenGöttingenGermany
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36
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Abstract
Studies have suggested that communication between taste cells shapes the gustatory signal before transmission to the brain. To further explore the possibility of intragemmal signal modulation, we adopted an optogenetic approach to stimulate sour-sensitive (Type III) taste cells using mice expressing Cre recombinase under a specific Type III cell promoter, Pkd2l1 (polycystic kidney disease-2-like 1), crossed with mice expressing Cre-dependent channelrhodopsin (ChR2). The application of blue light onto the tongue allowed for the specific stimulation of Type III cells and circumvented the nonspecific effects of chemical stimulation. To understand whether taste modality information is preprocessed in the taste bud before transmission to the sensory nerves, we recorded chorda tympani nerve activity during light and/or chemical tastant application to the tongue. To assess intragemmal modulation, we compared nerve responses to various tastants with or without concurrent light-induced activation of the Type III cells. Our results show that light significantly decreased taste responses to sweet, bitter, salty, and acidic stimuli. On the contrary, the light response was not consistently affected by sweet or bitter stimuli, suggesting that activation of Type II cells does not affect nerve responses to stimuli that activate Type III cells.
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Affiliation(s)
- Aurelie Vandenbeuch
- Department of Otolaryngology and Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO, USA
| | - Courtney E Wilson
- Department of Otolaryngology and Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO, USA
| | - Sue C Kinnamon
- Department of Otolaryngology and Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO, USA
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37
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Li H, Huang CY, Govorunova EG, Sineshchekov OA, Yi A, Rothschild KJ, Wang M, Zheng L, Spudich JL. The crystal structure of bromide-bound GtACR1 reveals a pre-activated state in the transmembrane anion tunnel. eLife 2021; 10:65903. [PMID: 33998458 PMCID: PMC8172240 DOI: 10.7554/elife.65903] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 12/31/2020] [Accepted: 05/16/2021] [Indexed: 12/16/2022] Open
Abstract
The crystal structure of the light-gated anion channel GtACR1 reported in our previous Research Article (Li et al., 2019) revealed a continuous tunnel traversing the protein from extracellular to intracellular pores. We proposed the tunnel as the conductance channel closed by three constrictions: C1 in the extracellular half, mid-membrane C2 containing the photoactive site, and C3 on the cytoplasmic side. Reported here, the crystal structure of bromide-bound GtACR1 reveals structural changes that relax the C1 and C3 constrictions, including a novel salt-bridge switch mechanism involving C1 and the photoactive site. These findings indicate that substrate binding induces a transition from an inactivated state to a pre-activated state in the dark that facilitates channel opening by reducing free energy in the tunnel constrictions. The results provide direct evidence that the tunnel is the closed form of the channel of GtACR1 and shed light on the light-gated channel activation mechanism.
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Affiliation(s)
- Hai Li
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center - McGovern Medical School, Houston, United States
| | - Chia-Ying Huang
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Elena G Govorunova
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center - McGovern Medical School, Houston, United States
| | - Oleg A Sineshchekov
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center - McGovern Medical School, Houston, United States
| | - Adrian Yi
- Molecular Biophysics Laboratory, Photonics Center and Department of Physics, Boston University, Boston, United States
| | - Kenneth J Rothschild
- Molecular Biophysics Laboratory, Photonics Center and Department of Physics, Boston University, Boston, United States
| | - Meitian Wang
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Lei Zheng
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center - McGovern Medical School, Houston, United States
| | - John L Spudich
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center - McGovern Medical School, Houston, United States
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38
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Guo T, Patel S, Shah D, Chi L, Emadi S, Pierce DM, Han M, Brumovsky PR, Feng B. Optical clearing reveals TNBS-induced morphological changes of VGLUT2-positive nerve fibers in mouse colorectum. Am J Physiol Gastrointest Liver Physiol 2021; 320:G644-G657. [PMID: 33533318 PMCID: PMC8238166 DOI: 10.1152/ajpgi.00363.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/12/2021] [Accepted: 01/27/2021] [Indexed: 01/31/2023]
Abstract
Colorectal hypersensitivity and sensitization of both mechanosensitive and mechanically insensitive afferents develop after intracolonic instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS) in the mouse, a model of postinfectious irritable bowel syndrome. In mice in which ∼80% of extrinsic colorectal afferents were labeled genetically using the promotor for vesicular glutamate transporter type 2 (VGLUT2), we systematically quantified the morphology of VGLUT2-positive axons in mouse colorectum 7-28 days following intracolonic TNBS treatment. After removal, the colorectum was distended (20 mmHg), fixed with paraformaldehyde, and optically cleared to image VGLUT2-positive axons throughout the colorectal wall thickness. We conducted vector path tracing of individual axons to allow systematic quantification of nerve fiber density and shape. Abundant VGLUT2-positive nerve fibers were present in most layers of the colorectum, except the serosal and longitudinal muscular layers. A small percentage of VGLUT2-positive myenteric plexus neurons was also detected. Intracolonic TNBS treatment significantly reduced the number of VGLUT2-positive nerve fibers in submucosal, myenteric plexus, and mucosal layers at day 7 post-TNBS, which mostly recovered by day 28. We also found that almost all fibers in the submucosa were meandering and curvy, with ∼10% showing pronounced curviness (quantified by the linearity index). TNBS treatment resulted in a significant reduction of the proportions of pronounced curvy fibers in the rectal region at 28 days post-TNBS. Altogether, the present morphological study reveals profound changes in the distribution of VGLUT2-positive fibers in mouse colorectum undergoing TNBS-induced colitis and draws attention to curvy fibers in the submucosa with potential roles in visceral nociception.NEW & NOTEWORTHY We conducted genetic labeling and optical clearing to visualize extrinsic sensory nerve fibers in whole-mount colorectum, which revealed widespread presence of axons in the submucosal layer. Remarkably, axons in the submucosa were meandering and curvy, in contrast to axons in other layers generally aligned with the basal tissues. Intracolonic TNBS treatment led to pronounced changes of nerve fiber density and curviness, suggesting nerve fiber morphologies as potentially contributing factors to sensory sensitization.
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Affiliation(s)
- Tiantian Guo
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
| | - Shivam Patel
- Department of Physiology and Neurobiology, University of Connecticut, Mansfield, Connecticut
| | - Dhruv Shah
- Department of Molecular and Cell Biology, University of Connecticut, Mansfield, Connecticut
| | - Ling Chi
- Department of Physiology and Neurobiology, University of Connecticut, Mansfield, Connecticut
| | - Sharareh Emadi
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
| | - David M Pierce
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
- Department of Mechanical Engineering, University of Connecticut, Mansfield, Connecticut
| | - Martin Han
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
| | - Pablo R Brumovsky
- Instituto de Investigaciones en Medicina Traslacional, National Scientific and Technical Research Council, Austral University, Buenos Aires, Argentina
| | - Bin Feng
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
- Department of Physiology and Neurobiology, University of Connecticut, Mansfield, Connecticut
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39
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Fujii K, Nakajo K, Egashira Y, Yamamoto Y, Kitada K, Taniguchi K, Kawai M, Tomiyama H, Kawakami K, Uchiyama K, Ono F. Gastrointestinal Neurons Expressing HCN4 Regulate Retrograde Peristalsis. Cell Rep 2021; 30:2879-2888.e3. [PMID: 32130893 DOI: 10.1016/j.celrep.2020.02.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 09/30/2019] [Accepted: 02/06/2020] [Indexed: 12/31/2022] Open
Abstract
Peristalsis is indispensable for physiological function of the gut. The enteric nervous system (ENS) plays an important role in regulating peristalsis. While the neural network regulating anterograde peristalsis, which migrates from the oral end to the anal end, is characterized to some extent, retrograde peristalsis remains unresolved with regards to its neural regulation. Using forward genetics in zebrafish, we reveal that a population of neurons expressing a hyperpolarization-activated nucleotide-gated channel HCN4 specifically regulates retrograde peristalsis. When HCN4 channels are blocked by an HCN channel inhibitor or morpholinos blocking the protein expression, retrograde peristalsis is specifically attenuated. Conversely, when HCN4(+) neurons expressing channelrhodopsin are activated by illumination, retrograde peristalsis is enhanced while anterograde peristalsis remains unchanged. We propose that HCN4(+) neurons in the ENS forward activating signals toward the oral end and simultaneously stimulate local circuits regulating the circular muscle.
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Affiliation(s)
- Kensuke Fujii
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Koichi Nakajo
- Department of Physiology, Osaka Medical College, Takatsuki, Japan; Division of Integrative Physiology, Department of Physiology, Jichi Medical University, Shimotsuke, Japan
| | | | | | - Kazuya Kitada
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Kohei Taniguchi
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Masaru Kawai
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Hideki Tomiyama
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics and Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Japan
| | - Kazuhisa Uchiyama
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Fumihito Ono
- Department of Physiology, Osaka Medical College, Takatsuki, Japan.
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40
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Oda K, Nomura T, Nakane T, Yamashita K, Inoue K, Ito S, Vierock J, Hirata K, Maturana AD, Katayama K, Ikuta T, Ishigami I, Izume T, Umeda R, Eguma R, Oishi S, Kasuya G, Kato T, Kusakizako T, Shihoya W, Shimada H, Takatsuji T, Takemoto M, Taniguchi R, Tomita A, Nakamura R, Fukuda M, Miyauchi H, Lee Y, Nango E, Tanaka R, Tanaka T, Sugahara M, Kimura T, Shimamura T, Fujiwara T, Yamanaka Y, Owada S, Joti Y, Tono K, Ishitani R, Hayashi S, Kandori H, Hegemann P, Iwata S, Kubo M, Nishizawa T, Nureki O. Time-resolved serial femtosecond crystallography reveals early structural changes in channelrhodopsin. eLife 2021; 10:62389. [PMID: 33752801 PMCID: PMC7987342 DOI: 10.7554/elife.62389] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [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: 08/23/2020] [Accepted: 02/15/2021] [Indexed: 01/17/2023] Open
Abstract
Channelrhodopsins (ChRs) are microbial light-gated ion channels utilized in optogenetics to control neural activity with light . Light absorption causes retinal chromophore isomerization and subsequent protein conformational changes visualized as optically distinguished intermediates, coupled with channel opening and closing. However, the detailed molecular events underlying channel gating remain unknown. We performed time-resolved serial femtosecond crystallographic analyses of ChR by using an X-ray free electron laser, which revealed conformational changes following photoactivation. The isomerized retinal adopts a twisted conformation and shifts toward the putative internal proton donor residues, consequently inducing an outward shift of TM3, as well as a local deformation in TM7. These early conformational changes in the pore-forming helices should be the triggers that lead to opening of the ion conducting pore.
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Affiliation(s)
- Kazumasa Oda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Takashi Nomura
- Graduate School of Life Science, University of Hyogo, Hyogo, Japan
| | - Takanori Nakane
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Keitaro Yamashita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Keiichi Inoue
- Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Shota Ito
- Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Johannes Vierock
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Kunio Hirata
- RIKEN SPring-8 Center, Hyogo, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Kawaguchi, Japan
| | - Andrés D Maturana
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Kota Katayama
- Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Tatsuya Ikuta
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Itsuki Ishigami
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Tamaki Izume
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Rie Umeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Ryuun Eguma
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Satomi Oishi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Go Kasuya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Takafumi Kato
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Wataru Shihoya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Hiroto Shimada
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Tomoyuki Takatsuji
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Mizuki Takemoto
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Reiya Taniguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Atsuhiro Tomita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Ryoki Nakamura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Masahiro Fukuda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Hirotake Miyauchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yongchan Lee
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Eriko Nango
- RIKEN SPring-8 Center, Hyogo, Japan.,Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Rie Tanaka
- RIKEN SPring-8 Center, Hyogo, Japan.,Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tomoyuki Tanaka
- RIKEN SPring-8 Center, Hyogo, Japan.,Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | - Tetsunari Kimura
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Japan
| | - Tatsuro Shimamura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takaaki Fujiwara
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yasuaki Yamanaka
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shigeki Owada
- RIKEN SPring-8 Center, Hyogo, Japan.,Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Yasumasa Joti
- RIKEN SPring-8 Center, Hyogo, Japan.,Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Kensuke Tono
- RIKEN SPring-8 Center, Hyogo, Japan.,Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Ryuichiro Ishitani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Shigehiko Hayashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Hideki Kandori
- Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Peter Hegemann
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - So Iwata
- RIKEN SPring-8 Center, Hyogo, Japan.,Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Minoru Kubo
- Graduate School of Life Science, University of Hyogo, Hyogo, Japan
| | - Tomohiro Nishizawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Kawaguchi, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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41
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Chen Z, Tsytsarev V, Finfrock YZ, Antipova OA, Cai Z, Arakawa H, Lischka FW, Hooks BM, Wilton R, Wang D, Liu Y, Gaitan B, Tao Y, Chen Y, Erzurumlu RS, Yang H, Rozhkova EA. Wireless Optogenetic Modulation of Cortical Neurons Enabled by Radioluminescent Nanoparticles. ACS Nano 2021; 15:5201-5208. [PMID: 33625219 DOI: 10.1021/acsnano.0c10436] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [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: 05/25/2023]
Abstract
While offering high-precision control of neural circuits, optogenetics is hampered by the necessity to implant fiber-optic waveguides in order to deliver photons to genetically engineered light-gated neurons in the brain. Unlike laser light, X-rays freely pass biological barriers. Here we show that radioluminescent Gd2(WO4)3:Eu nanoparticles, which absorb external X-rays energy and then downconvert it into optical photons with wavelengths of ∼610 nm, can be used for the transcranial stimulation of cortical neurons expressing red-shifted, ∼590-630 nm, channelrhodopsin ReaChR, thereby promoting optogenetic neural control to the practical implementation of minimally invasive wireless deep brain stimulation.
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Affiliation(s)
- Zhaowei Chen
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
- Institute of Food Safety and Environment Monitoring, MOE Key Laboratory for Analytical Science of Food Safety and Biology, College of Chemistry, Fuzhou University, Fuzhou 350108, People's Republic of China
| | - Vassiliy Tsytsarev
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, College Park, Maryland 20742, United States
| | - Y Zou Finfrock
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
- Science Division, Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2 V3, Canada
| | - Olga A Antipova
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Zhonghou Cai
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Hiroyuki Arakawa
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn Street, Baltimore, Maryland 21201, United States
| | - Fritz W Lischka
- Biomedical Instrumentation Center, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814-4799, United States
| | - Bryan M Hooks
- Department of Neurobiology, University of Pittsburgh, 3500 Terrace Street, Suite W1458, Pittsburgh, Pennsylvania 15213-2500, United States
| | - Rosemarie Wilton
- Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Dongyi Wang
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, College Park, Maryland 20742, United States
| | - Yi Liu
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, College Park, Maryland 20742, United States
| | - Brandon Gaitan
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, College Park, Maryland 20742, United States
| | - Yang Tao
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, College Park, Maryland 20742, United States
| | - Yu Chen
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, College Park, Maryland 20742, United States
| | - Reha S Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn Street, Baltimore, Maryland 21201, United States
| | - Huanghao Yang
- Institute of Food Safety and Environment Monitoring, MOE Key Laboratory for Analytical Science of Food Safety and Biology, College of Chemistry, Fuzhou University, Fuzhou 350108, People's Republic of China
| | - Elena A Rozhkova
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
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Vogt M, Schulz B, Wagdi A, Lebert J, van Belle GJ, Christoph J, Bruegmann T, Patejdl R. Direct optogenetic stimulation of smooth muscle cells to control gastric contractility. Am J Cancer Res 2021; 11:5569-5584. [PMID: 33859764 PMCID: PMC8039938 DOI: 10.7150/thno.53883] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/12/2021] [Indexed: 12/21/2022] Open
Abstract
Rationale: Antral peristalsis is responsible for gastric emptying. Its failure is called gastroparesis and often caused by dysfunction of enteric neurons and interstitial cells of Cajal (ICC). Current treatment options, including gastric electrical stimulation, are non-satisfying and may improve symptoms but commonly fail to restore gastric emptying. Herein, we explore direct optogenetic stimulation of smooth muscle cells (SMC) via the light-gated non-selective cation channel Channelrhodopsin2 (ChR2) to control gastric motor function. Methods: We used a transgenic mouse model expressing ChR2 in fusion with eYFP under the control of the chicken-β-actin promoter. We performed patch clamp experiments to quantify light-induced currents in isolated SMC, Ca2+ imaging and isometric force measurements of antral smooth muscle strips as well as pressure recordings of intact stomachs to evaluate contractile responses. Light-induced propulsion of gastric contents from the isolated stomach preparation was quantified in video recordings. We furthermore tested optogenetic stimulation in a gastroparesis model induced by neuronal- and ICC-specific damage through methylene blue photo-toxicity. Results: In the stomachs, eYFP signals were restricted to SMC in which blue light (460 nm) induced inward currents typical for ChR2. These depolarizing currents led to contractions in antral smooth muscle strips that were stronger than those triggered by supramaximal electrical field stimulation and comparable to those evoked by global depolarization with high K+ concentration. In the intact stomach, panoramic illumination efficiently increased intragastric pressure achieving 239±46% (n=6) of the pressure induced by electrical field stimulation and triggered gastric transport. Within the gastroparesis model, electric field stimulation completely failed but light still efficiently generated pressure waves. Conclusions: We demonstrate direct optogenetic stimulation of SMC to control gastric contractility. This completely new approach could allow for the restoration of motility in gastroparesis in the future.
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Paschen E, Elgueta C, Heining K, Vieira DM, Kleis P, Orcinha C, Häussler U, Bartos M, Egert U, Janz P, Haas CA. Hippocampal low-frequency stimulation prevents seizure generation in a mouse model of mesial temporal lobe epilepsy. eLife 2020; 9:54518. [PMID: 33349333 PMCID: PMC7800381 DOI: 10.7554/elife.54518] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [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: 12/17/2019] [Accepted: 12/13/2020] [Indexed: 12/18/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) is the most common form of focal, pharmacoresistant epilepsy in adults and is often associated with hippocampal sclerosis. Here, we established the efficacy of optogenetic and electrical low-frequency stimulation (LFS) in interfering with seizure generation in a mouse model of MTLE. Specifically, we applied LFS in the sclerotic hippocampus to study the effects on spontaneous subclinical and evoked generalized seizures. We found that stimulation at 1 Hz for 1 hr resulted in an almost complete suppression of spontaneous seizures in both hippocampi. This seizure-suppressive action during daily stimulation remained stable over several weeks. Furthermore, LFS for 30 min before a pro-convulsive stimulus successfully prevented seizure generalization. Finally, acute slice experiments revealed a reduced efficacy of perforant path transmission onto granule cells upon LFS. Taken together, our results suggest that hippocampal LFS constitutes a promising approach for seizure control in MTLE.
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Affiliation(s)
- Enya Paschen
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Claudio Elgueta
- Systemic and Cellular Neurophysiology, Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Katharina Heining
- Biomicrotechnology, Department of Microsystems Engineering - IMTEK, Faculty of Engineering, University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Diego M Vieira
- Biomicrotechnology, Department of Microsystems Engineering - IMTEK, Faculty of Engineering, University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Piret Kleis
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Catarina Orcinha
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Ute Häussler
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Systemic and Cellular Neurophysiology, Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ulrich Egert
- Biomicrotechnology, Department of Microsystems Engineering - IMTEK, Faculty of Engineering, University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Philipp Janz
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Carola A Haas
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Diehl MM, Iravedra-Garcia JM, Morán-Sierra J, Rojas-Bowe G, Gonzalez-Diaz FN, Valentín-Valentín VP, Quirk GJ. Divergent projections of the prelimbic cortex bidirectionally regulate active avoidance. eLife 2020; 9:59281. [PMID: 33054975 PMCID: PMC7588229 DOI: 10.7554/elife.59281] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [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: 05/28/2020] [Accepted: 10/14/2020] [Indexed: 12/12/2022] Open
Abstract
The prefrontal cortex (PFC) integrates incoming information to guide our actions. When motivation for food-seeking competes with avoidance of danger, the PFC likely plays a role in selecting the optimal choice. In platform-mediated active avoidance, rats avoid a tone-signaled footshock by stepping onto a nearby platform, delaying access to sucrose pellets. This avoidance requires prelimbic (PL) PFC, basolateral amygdala (BLA), and ventral striatum (VS). We previously showed that inhibitory tone responses of PL neurons correlate with avoidability of shock (Diehl et al., 2018). Here, we optogenetically modulated PL terminals in VS and BLA to identify PL outputs regulating avoidance. Photoactivating PL-VS projections reduced avoidance, whereas photoactivating PL-BLA projections increased avoidance. Moreover, photosilencing PL-BLA or BLA-VS projections reduced avoidance, suggesting that VS receives opposing inputs from PL and BLA. Bidirectional modulation of avoidance by PL projections to VS and BLA enables the animal to make appropriate decisions when faced with competing drives.
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Affiliation(s)
- Maria M Diehl
- Departments of Psychiatry and Neurobiology & Anatomy, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
| | - Jorge M Iravedra-Garcia
- Departments of Psychiatry and Neurobiology & Anatomy, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
| | - Jonathan Morán-Sierra
- Departments of Psychiatry and Neurobiology & Anatomy, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
| | - Gabriel Rojas-Bowe
- Departments of Psychiatry and Neurobiology & Anatomy, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
| | - Fabiola N Gonzalez-Diaz
- Departments of Psychiatry and Neurobiology & Anatomy, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
| | - Viviana P Valentín-Valentín
- Departments of Psychiatry and Neurobiology & Anatomy, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
| | - Gregory J Quirk
- Departments of Psychiatry and Neurobiology & Anatomy, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
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45
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Tang Q, Tsytsarev V, Yan F, Wang C, Erzurumlu RS, Chen Y. In vivo voltage-sensitive dye imaging of mouse cortical activity with mesoscopic optical tomography. Neurophotonics 2020; 7:041402. [PMID: 33274250 PMCID: PMC7708784 DOI: 10.1117/1.nph.7.4.041402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 11/11/2020] [Indexed: 05/11/2023]
Abstract
Significance: Cellular layering is a hallmark of the mammalian neocortex with layer and cell type-specific connections within the cortical mantle and subcortical connections. A key challenge in studying circuit function within the neocortex is to understand the spatial and temporal patterns of information flow between different columns and layers. Aim: We aimed to investigate the three-dimensional (3D) layer- and area-specific interactions in mouse cortex in vivo. Approach: We applied a new promising neuroimaging method-fluorescence laminar optical tomography in combination with voltage-sensitive dye imaging (VSDi). VSDi is a powerful technique for interrogating membrane potential dynamics in assemblies of cortical neurons, but it is traditionally used for two-dimensional (2D) imaging. Our mesoscopic technique allows visualization of neuronal activity in a 3D manner with high temporal resolution. Results: We first demonstrated the depth-resolved capability of 3D mesoscopic imaging technology in Thy1-ChR2-YFP transgenic mice. Next, we recorded the long-range functional projections between sensory cortex (S1) and motor cortex (M1) in mice, in vivo, following single whisker deflection. Conclusions: The results show that mesoscopic imaging technique has the potential to investigate the layer-specific neural connectivity in the mouse cortex in vivo. Combination of mesoscopic imaging technique with optogenetic control strategy is a promising platform for determining depth-resolved interactions between cortical circuit elements.
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Affiliation(s)
- Qinggong Tang
- University of Oklahoma, Stephenson School of Biomedical Engineering, Norman, Oklahoma, United States
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
- Address all correspondence to Qinggong Tang, ; Reha S. Erzurumlu, ; Yu Chen,
| | - Vassiliy Tsytsarev
- University of Maryland School of Medicine, Department of Anatomy and Neurobiology, Baltimore, Maryland, United States
| | - Feng Yan
- University of Oklahoma, Stephenson School of Biomedical Engineering, Norman, Oklahoma, United States
| | - Chen Wang
- University of Oklahoma, Stephenson School of Biomedical Engineering, Norman, Oklahoma, United States
| | - Reha S. Erzurumlu
- University of Maryland School of Medicine, Department of Anatomy and Neurobiology, Baltimore, Maryland, United States
- Address all correspondence to Qinggong Tang, ; Reha S. Erzurumlu, ; Yu Chen,
| | - Yu Chen
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
- University of Massachusetts, Department of Biomedical Engineering, Amherst, Massachusetts, United States
- Address all correspondence to Qinggong Tang, ; Reha S. Erzurumlu, ; Yu Chen,
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46
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Babl SS, Rummell BP, Sigurdsson T. The Spatial Extent of Optogenetic Silencing in Transgenic Mice Expressing Channelrhodopsin in Inhibitory Interneurons. Cell Rep 2020; 29:1381-1395.e4. [PMID: 31665647 DOI: 10.1016/j.celrep.2019.09.049] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [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: 04/05/2019] [Revised: 08/05/2019] [Accepted: 09/18/2019] [Indexed: 02/09/2023] Open
Abstract
Optogenetic stimulation of inhibitory interneurons has become a commonly used strategy for silencing neuronal activity. This is typically achieved using transgenic mice expressing excitatory opsins in inhibitory interneurons throughout the brain, raising the question of how spatially extensive the resulting inhibition is. Here, we characterize neuronal silencing in VGAT-ChR2 mice, which express channelrhodopsin-2 in inhibitory interneurons, as a function of light intensity and distance from the light source in several cortical and subcortical regions. We show that light stimulation, even at relatively low intensities, causes inhibition not only in brain regions targeted for silencing but also in their subjacent areas. In contrast, virus-mediated expression of an inhibitory opsin enables robust silencing that is restricted to the region of opsin expression. Our results reveal important constraints on using inhibitory interneuron activation to silence neuronal activity and emphasize the necessity of carefully controlling light stimulation parameters when using this silencing strategy.
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Affiliation(s)
- Susanne Stefanie Babl
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany
| | - Brian Paul Rummell
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany
| | - Torfi Sigurdsson
- Institute of Neurophysiology, Neuroscience Center, Goethe University, Frankfurt, Germany.
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47
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Fenno LE, Ramakrishnan C, Kim YS, Evans KE, Lo M, Vesuna S, Inoue M, Cheung KYM, Yuen E, Pichamoorthy N, Hong ASO, Deisseroth K. Comprehensive Dual- and Triple-Feature Intersectional Single-Vector Delivery of Diverse Functional Payloads to Cells of Behaving Mammals. Neuron 2020; 107:836-853.e11. [PMID: 32574559 PMCID: PMC7687746 DOI: 10.1016/j.neuron.2020.06.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [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] [Received: 03/20/2020] [Revised: 05/08/2020] [Accepted: 05/29/2020] [Indexed: 01/12/2023]
Abstract
The resolution and dimensionality with which biologists can characterize cell types have expanded dramatically in recent years, and intersectional consideration of such features (e.g., multiple gene expression and anatomical parameters) is increasingly understood to be essential. At the same time, genetically targeted technology for writing in and reading out activity patterns for cells in living organisms has enabled causal investigation in physiology and behavior; however, cell-type-specific delivery of these tools (including microbial opsins for optogenetics and genetically encoded Ca2+ indicators) has thus far fallen short of versatile targeting to cells jointly defined by many individually selected features. Here, we develop a comprehensive intersectional targeting toolbox including 39 novel vectors for joint-feature-targeted delivery of 13 molecular payloads (including opsins, indicators, and fluorophores), systematic approaches for development and optimization of new intersectional tools, hardware for in vivo monitoring of expression dynamics, and the first versatile single-virus tools (Triplesect) that enable targeting of triply defined cell types.
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Affiliation(s)
- Lief E Fenno
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Charu Ramakrishnan
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Yoon Seok Kim
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kathryn E Evans
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Maisie Lo
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Sam Vesuna
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Masatoshi Inoue
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kathy Y M Cheung
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Elle Yuen
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | | | - Alice S O Hong
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Karl Deisseroth
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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48
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Octeau JC, Gangwani MR, Allam SL, Tran D, Huang S, Hoang-Trong TM, Golshani P, Rumbell TH, Kozloski JR, Khakh BS. Transient, Consequential Increases in Extracellular Potassium Ions Accompany Channelrhodopsin2 Excitation. Cell Rep 2020; 27:2249-2261.e7. [PMID: 31116972 PMCID: PMC6582980 DOI: 10.1016/j.celrep.2019.04.078] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [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: 09/13/2018] [Revised: 03/04/2019] [Accepted: 04/17/2019] [Indexed: 12/13/2022] Open
Abstract
Channelrhodopsin2 (ChR2) optogenetic excitation is widely used to study neurons, astrocytes, and circuits. Using complementary approaches in situ and in vivo, we found that ChR2 stimulation leads to significant transient elevation of extracellular potassium ions by ~5 mM. Such elevations were detected in ChR2-expressing mice, following local in vivo expression of ChR2(H134R) with adeno-associated viruses (AAVs), in different brain areas and when ChR2 was expressed in neurons or astrocytes. In particular, ChR2-mediated excitation of striatal astrocytes was sufficient to increase medium spiny neuron (MSN) excitability and immediate early gene expression. The effects on MSN excitability were recapitulated in silico with a computational MSN model and detected in vivo as increased action potential firing in awake, behaving mice. We show that transient, physiologically consequential increases in extracellular potassium ions accompany ChR2 optogenetic excitation. This coincidental effect may be important to consider during astrocyte studies employing ChR2 to interrogate neural circuits and animal behavior. Using multiple approaches, Octeau et al. discover that optogenetic excitation of ChR2-expressing cells leads to significant transient extracellular potassium ion elevations that increase neuronal excitability and immediate early gene expression in neurons following in vivo stimulation.
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Affiliation(s)
- J Christopher Octeau
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Mohitkumar R Gangwani
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Sushmita L Allam
- IBM T.J. Watson Research Center, P.O. Box 218, 1101 Kitchawan Road, Yorktown Heights, NY 10598, USA
| | - Duy Tran
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Shuhan Huang
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Tuan M Hoang-Trong
- IBM T.J. Watson Research Center, P.O. Box 218, 1101 Kitchawan Road, Yorktown Heights, NY 10598, USA
| | - Peyman Golshani
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Timothy H Rumbell
- IBM T.J. Watson Research Center, P.O. Box 218, 1101 Kitchawan Road, Yorktown Heights, NY 10598, USA
| | - James R Kozloski
- IBM T.J. Watson Research Center, P.O. Box 218, 1101 Kitchawan Road, Yorktown Heights, NY 10598, USA
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA.
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49
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Nelson AR, Sagare MA, Wang Y, Kisler K, Zhao Z, Zlokovic BV. Channelrhodopsin Excitation Contracts Brain Pericytes and Reduces Blood Flow in the Aging Mouse Brain in vivo. Front Aging Neurosci 2020; 12:108. [PMID: 32410982 PMCID: PMC7201096 DOI: 10.3389/fnagi.2020.00108] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/30/2020] [Indexed: 01/02/2023] Open
Abstract
Brains depend on blood flow for the delivery of oxygen and nutrients essential for proper neuronal and synaptic functioning. French physiologist Rouget was the first to describe pericytes in 1873 as regularly arranged longitudinal amoeboid cells on capillaries that have a muscular coat, implying that these are contractile cells that regulate blood flow. Although there have been >30 publications from different groups, including our group, demonstrating that pericytes are contractile cells that can regulate hemodynamic responses in the brain, the role of pericytes in controlling cerebral blood flow (CBF) has not been confirmed by all studies. Moreover, recent studies using different optogenetic models to express light-sensitive channelrhodopsin-2 (ChR2) cation channels in pericytes were not conclusive; one, suggesting that pericytes expressing ChR2 do not contract after light stimulus, and the other, demonstrating contraction of pericytes expressing ChR2 after light stimulus. Since two-photon optogenetics provides a powerful tool to study mechanisms of blood flow regulation at the level of brain capillaries, we re-examined the contractility of brain pericytes in vivo using a new optogenetic model developed by crossing our new inducible pericyte-specific CreER mouse line with ChR2 mice. We induced expression of ChR2 in pericytes with tamoxifen, excited ChR2 by 488 nm light, and monitored pericyte contractility, brain capillary diameter changes, and red blood cell (RBC) velocity in aged mice by in vivo two-photon microscopy. Excitation of ChR2 resulted in pericyte contraction followed by constriction of the underlying capillary leading to approximately an 8% decrease (p = 0.006) in capillary diameter. ChR2 excitation in pericytes substantially reduced capillary RBC flow by 42% (p = 0.03) during the stimulation period compared to the velocity before stimulation. Our data suggests that pericytes contract in vivo and regulate capillary blood flow in the aging mouse brain. By extension, this might have implications for neurological disorders of the aging human brain associated with neurovascular dysfunction and pericyte loss such as stroke and Alzheimer's disease.
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Affiliation(s)
| | | | | | | | | | - Berislav V. Zlokovic
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, United States
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Guo K, Yamawaki N, Barrett JM, Tapies M, Shepherd GMG. Cortico-Thalamo-Cortical Circuits of Mouse Forelimb S1 Are Organized Primarily as Recurrent Loops. J Neurosci 2020; 40:2849-2858. [PMID: 32075900 PMCID: PMC7117898 DOI: 10.1523/jneurosci.2277-19.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [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] [Received: 09/19/2019] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 11/21/2022] Open
Abstract
Cortical projections to the thalamus arise from corticothalamic (CT) neurons in layer 6 and pyramidal tract-type (PT) neurons in layer 5B. We dissected the excitatory synaptic connections in the somatosensory thalamus formed by CT and PT neurons of the primary somatosensory (S1) cortex, focusing on mouse forelimb S1. Mice of both sexes were studied. The CT neurons in S1 synaptically excited S1-projecting thalamocortical (TC) neurons in subregions of both the ventral posterior lateral and posterior (PO) nuclei, forming a pair of recurrent cortico-thalamo-cortical (C-T-C) loops. The PT neurons in S1 also formed a recurrent loop with S1-projecting TC neurons in the same subregion of the PO. The PT neurons in the adjacent primary motor (M1) cortex formed a separate recurrent loop with M1-projecting TC neurons in a nearby subregion of the PO. Collectively, our results reveal that C-T-C circuits of mouse forelimb S1 are primarily organized as multiple cortical cell-type-specific and thalamic subnucleus-specific recurrent loops, with both CT and PT neurons providing the strongest excitatory input to TC neurons that project back to S1. The findings, together with those of related studies of C-T-C circuits, thus suggest that recurrently projecting thalamocortical neurons are the principal targets of cortical excitatory input to the mouse somatosensory and motor thalamus.SIGNIFICANCE STATEMENT Bidirectional cortical communication with the thalamus is considered an important aspect of sensorimotor integration for active touch in the somatosensory system, but the cellular organization of the circuits mediating this process is not well understood. We used an approach combining cell-type-specific anterograde optogenetic excitation with single-cell recordings targeted to retrogradely labeled thalamocortical neurons to dissect these circuits. The findings reveal a consistent pattern: cortical projections to the somatosensory thalamus target thalamocortical neurons that project back to the same cortical area. Commonalities of these findings to previous descriptions of related circuits in other areas suggest that cortico-thalamo-cortical circuits may generally be organized primarily as recurrent loops.
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Affiliation(s)
- KuangHua Guo
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Naoki Yamawaki
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - John M Barrett
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Martinna Tapies
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Gordon M G Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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