201
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Beck C, Gong Y. A high-speed, bright, red fluorescent voltage sensor to detect neural activity. Sci Rep 2019; 9:15878. [PMID: 31685893 PMCID: PMC6828731 DOI: 10.1038/s41598-019-52370-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/16/2019] [Indexed: 11/27/2022] Open
Abstract
Genetically encoded voltage indicators (GEVIs) have emerged as a technology to optically record neural activity with genetic specificity and millisecond-scale temporal resolution using fluorescence microscopy. GEVIs have demonstrated ultra-fast kinetics and high spike detection fidelity in vivo, but existing red-fluorescent voltage indicators fall short of the response and brightness achieved by green fluorescent protein-based sensors. Furthermore, red-fluorescent GEVIs suffer from incomplete spectral separation from green sensors and blue-light-activated optogenetic actuators. We have developed Ace-mScarlet, a red fluorescent GEVI that fuses Ace2N, a voltage-sensitive inhibitory rhodopsin, with mScarlet, a bright red fluorescent protein (FP). Through fluorescence resonance energy transfer (FRET), our sensor detects changes in membrane voltage with high sensitivity and brightness and has kinetics comparable to the fastest green fluorescent sensors. Ace-mScarlet's red-shifted absorption and emission spectra facilitate virtually complete spectral separation when used in combination with green-fluorescent sensors or with blue-light-sensitive sensors and rhodopsins. This spectral separation enables both simultaneous imaging in two separate wavelength channels and high-fidelity voltage recordings during simultaneous optogenetic perturbation.
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Affiliation(s)
- Connor Beck
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Yiyang Gong
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
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202
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Jing M, Zhang Y, Wang H, Li Y. G-protein-coupled receptor-based sensors for imaging neurochemicals with high sensitivity and specificity. J Neurochem 2019; 151:279-288. [PMID: 31419844 PMCID: PMC6819231 DOI: 10.1111/jnc.14855] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/01/2019] [Accepted: 08/01/2019] [Indexed: 01/02/2023]
Abstract
Neurotransmitters and neuromodulators are key neurochemicals that mediate cell-cell communication, maintain the body's homeostasis, and control a wide range of biological processes. Thus, dysregulation of neurochemical signaling is associated with a range of psychiatric disorders and neurological diseases. Understanding the physiological and pathophysiological functions of neurochemicals, particularly in complex biological systems in vivo, requires tools that can probe their dynamics with high sensitivity and specificity. Recently, genetically encoded fluorescent sensors for visualizing specific neurochemicals were developed by coupling neurochemical-sensing G-protein-coupled receptors (GPCRs) with a circular-permutated fluorescent protein. These GPCR-based sensors can monitor the dynamics of neurochemicals in behaving animals with high spatiotemporal resolution. Here, we review recent progress regarding the development and application of GPCR-based sensors for imaging neurochemicals, and we discuss future perspectives.
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Affiliation(s)
- Miao Jing
- Chinese Institute for Brain Research, Beijing, China
| | - Yajun Zhang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Huan Wang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
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203
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Soman SK, Bazała M, Keatinge M, Bandmann O, Kuznicki J. Restriction of mitochondrial calcium overload by mcu inactivation renders a neuroprotective effect in zebrafish models of Parkinson's disease. Biol Open 2019; 8:bio044347. [PMID: 31548178 PMCID: PMC6826286 DOI: 10.1242/bio.044347] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/13/2019] [Indexed: 12/21/2022] Open
Abstract
The loss of dopaminergic neurons (DA) is a pathological hallmark of sporadic and familial forms of Parkinson's disease (PD). We have previously shown that inhibiting mitochondrial calcium uniporter (mcu) using morpholinos can rescue DA neurons in the PTEN-induced putative kinase 1 (pink1)-/- zebrafish model of PD. In this article, we show results from our studies in mcu knockout zebrafish, which was generated using the CRISPR/Cas9 system. Functional assays confirmed impaired mitochondrial calcium influx in mcu -/- zebrafish. We also used in vivo calcium imaging and fluorescent assays in purified mitochondria to investigate mitochondrial calcium dynamics in a pink1 -/- zebrafish model of PD. Mitochondrial morphology was evaluated in DA neurons and muscle fibers using immunolabeling and transgenic lines, respectively. We observed diminished mitochondrial area in DA neurons of pink1 -/- zebrafish, while deletion of mcu restored mitochondrial area. In contrast, the mitochondrial volume in muscle fibers was not restored after inactivation of mcu in pink1 -/- zebrafish. Mitochondrial calcium overload coupled with depolarization of mitochondrial membrane potential leads to mitochondrial dysfunction in the pink1 -/- zebrafish model of PD. We used in situ hybridization and immunohistochemical labeling of DA neurons to evaluate the effect of mcu deletion on DA neuronal clusters in the ventral telencephalon of zebrafish brain. We show that DA neurons are rescued after deletion of mcu in pink1 -/- and the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) zebrafish model of PD. Thus, inactivation of mcu is protective in both genetic and chemical models of PD. Our data reveal that regulating mcu function could be an effective therapeutic target in PD pathology.
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Affiliation(s)
- Smijin K Soman
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, Księcia Trojdena 4, 02-109, Warsaw, Poland
| | - Michal Bazała
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, Księcia Trojdena 4, 02-109, Warsaw, Poland
| | - Marcus Keatinge
- Medical Research Council Centre for Developmental and Biomedical Genetics, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385a Glossop Road, Sheffield, S10 2HQ, UK
| | - Oliver Bandmann
- Medical Research Council Centre for Developmental and Biomedical Genetics, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385a Glossop Road, Sheffield, S10 2HQ, UK
| | - Jacek Kuznicki
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, Księcia Trojdena 4, 02-109, Warsaw, Poland
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204
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Gribizis A, Ge X, Daigle TL, Ackman JB, Zeng H, Lee D, Crair MC. Visual Cortex Gains Independence from Peripheral Drive before Eye Opening. Neuron 2019; 104:711-723.e3. [PMID: 31561919 DOI: 10.1016/j.neuron.2019.08.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/15/2019] [Accepted: 08/08/2019] [Indexed: 10/26/2022]
Abstract
Visual spatial perception in the mammalian brain occurs through two parallel pathways: one reaches the primary visual cortex (V1) through the thalamus and another the superior colliculus (SC) via direct projections from the retina. The origin, development, and relative function of these two evolutionarily distinct pathways remain obscure. We examined the early functional development of both pathways by simultaneously imaging pre- and post-synaptic spontaneous neuronal activity. We observed that the quality of retinal activity transfer to the thalamus and superior colliculus does not change across the first two postnatal weeks. However, beginning in the second postnatal week, retinal activity does not drive V1 as strongly as earlier wave activity, suggesting that intrinsic cortical activity competes with signals from the sensory periphery as the cortex matures. Together, these findings bring new insight into the function of the SC and V1 and the role of peripheral activity in driving both circuits across development.
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Affiliation(s)
- Alexandra Gribizis
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Xinxin Ge
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Tanya L Daigle
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - James B Ackman
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Daeyeol Lee
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Michael C Crair
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA.
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205
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Abstract
Retinal function has long been studied with psychophysical methods in humans, whereas detailed functional studies of vision have been conducted mostly in animals owing to the invasive nature of physiological approaches. There are exceptions to this generalization, for example, the electroretinogram. This review examines exciting recent advances using in vivo retinal imaging to understand the function of retinal neurons. In some cases, the methods have existed for years and are still being optimized. In others, new methods such as optophysiology are revealing novel patterns of retinal function in animal models that have the potential to change our understanding of the functional capacity of the retina. Together, the advances in retinal imaging mark an important milestone that shifts attention away from anatomy alone and begins to probe the function of healthy and diseased eyes.
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Affiliation(s)
- Jennifer J Hunter
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York 14604, USA; , ,
- The Institute of Optics and Department of Biomedical Engineering, University of Rochester, Rochester, New York 14604, USA
| | - William H Merigan
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York 14604, USA; , ,
| | - Jesse B Schallek
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York 14604, USA; , ,
- Department of Neuroscience, University of Rochester, Rochester, New York 14604, USA
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206
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Steuer Costa W, Van der Auwera P, Glock C, Liewald JF, Bach M, Schüler C, Wabnig S, Oranth A, Masurat F, Bringmann H, Schoofs L, Stelzer EHK, Fischer SC, Gottschalk A. A GABAergic and peptidergic sleep neuron as a locomotion stop neuron with compartmentalized Ca2+ dynamics. Nat Commun 2019; 10:4095. [PMID: 31506439 PMCID: PMC6736843 DOI: 10.1038/s41467-019-12098-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 08/21/2019] [Indexed: 11/09/2022] Open
Abstract
Animals must slow or halt locomotion to integrate sensory inputs or to change direction. In Caenorhabditis elegans, the GABAergic and peptidergic neuron RIS mediates developmentally timed quiescence. Here, we show RIS functions additionally as a locomotion stop neuron. RIS optogenetic stimulation caused acute and persistent inhibition of locomotion and pharyngeal pumping, phenotypes requiring FLP-11 neuropeptides and GABA. RIS photoactivation allows the animal to maintain its body posture by sustaining muscle tone, yet inactivating motor neuron oscillatory activity. During locomotion, RIS axonal Ca2+ signals revealed functional compartmentalization: Activity in the nerve ring process correlated with locomotion stop, while activity in a branch correlated with induced reversals. GABA was required to induce, and FLP-11 neuropeptides were required to sustain locomotion stop. RIS attenuates neuronal activity and inhibits movement, possibly enabling sensory integration and decision making, and exemplifies dual use of one cell across development in a compact nervous system.
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Affiliation(s)
- Wagner Steuer Costa
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Petrus Van der Auwera
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.,Functional Genomics and Proteomics Group, Department of Biology, KU Leuven, Naamsestraat 59 - box 2465, 3000, Leuven, Belgium
| | - Caspar Glock
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.,Max-Planck-Institute for Brain Research, Max-von-Laue-Strasse 4, 60438, Frankfurt, Germany
| | - Jana F Liewald
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Maximilian Bach
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Christina Schüler
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Sebastian Wabnig
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.,od green GmbH, Passauerstrasse 34, 4780, Schärding am Inn, Austria
| | - Alexandra Oranth
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Florentin Masurat
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Henrik Bringmann
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Department of Biology, University of Marburg, Karl-von-Frisch-Strasse 8, 35043, Marburg, Germany
| | - Liliane Schoofs
- Functional Genomics and Proteomics Group, Department of Biology, KU Leuven, Naamsestraat 59 - box 2465, 3000, Leuven, Belgium
| | - Ernst H K Stelzer
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Strasse 13, 60439, Frankfurt, Germany
| | - Sabine C Fischer
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Strasse 13, 60439, Frankfurt, Germany.,Center for Computational and Theoretical Biology (CCTB), University of Würzburg, Campus Hubland Nord 32, 97074, Würzburg, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany. .,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.
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207
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Woldemariam S, Nagpal J, Hill T, Li J, Schneider MW, Shankar R, Futey M, Varshney A, Ali N, Mitchell J, Andersen K, Barsi-Rhyne B, Tran A, Costa WS, Krzyzanowski MC, Yu YV, Brueggemann C, Hamilton OS, Ferkey DM, VanHoven M, Sengupta P, Gottschalk A, L'Etoile N. Using a Robust and Sensitive GFP-Based cGMP Sensor for Real-Time Imaging in Intact Caenorhabditis elegans. Genetics 2019; 213:59-77. [PMID: 31331946 PMCID: PMC6727795 DOI: 10.1534/genetics.119.302392] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 07/05/2019] [Indexed: 12/31/2022] Open
Abstract
cGMP plays a role in sensory signaling and plasticity by regulating ion channels, phosphodiesterases, and kinases. Studies that primarily used genetic and biochemical tools suggest that cGMP is spatiotemporally regulated in multiple sensory modalities. FRET- and GFP-based cGMP sensors were developed to visualize cGMP in primary cell culture and Caenorhabditis elegans to corroborate these findings. While a FRET-based sensor has been used in an intact animal to visualize cGMP, the requirement of a multiple emission system limits its ability to be used on its own as well as with other fluorophores. Here, we demonstrate that a C. elegans codon-optimized version of the cpEGFP-based cGMP sensor FlincG3 can be used to visualize rapidly changing cGMP levels in living, behaving C. elegans We coexpressed FlincG3 with the blue-light-activated guanylyl cyclases BeCyclOp and bPGC in body wall muscles, and found that the rate of change in FlincG3 fluorescence correlated with the rate of cGMP production by each cyclase. Furthermore, we show that FlincG3 responds to cultivation temperature, NaCl concentration changes, and sodium dodecyl sulfate in the sensory neurons AFD, ASEL/R, and PHB, respectively. Intriguingly, FlincG3 fluorescence in ASEL and ASER decreased in response to a NaCl concentration upstep and downstep, respectively, which is opposite in sign to the coexpressed calcium sensor jRGECO1a and previously published calcium recordings. These results illustrate that FlincG3 can be used to report rapidly changing cGMP levels in an intact animal, and that the reporter can potentially reveal unexpected spatiotemporal landscapes of cGMP in response to stimuli.
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Affiliation(s)
- Sarah Woldemariam
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, California 94158
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
| | - Jatin Nagpal
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Tyler Hill
- Neuroscience Graduate Program, Brandeis University, Waltham, Massachusetts 02453
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Joy Li
- Department of Biological Sciences, San Jose State University, California 95192
| | - Martin W Schneider
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Raakhee Shankar
- Department of Biological Sciences, San Jose State University, California 95192
| | - Mary Futey
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
| | - Aruna Varshney
- Department of Biological Sciences, San Jose State University, California 95192
| | - Nebat Ali
- Department of Biological Sciences, San Jose State University, California 95192
| | - Jordan Mitchell
- Department of Biological Sciences, San Jose State University, California 95192
| | - Kristine Andersen
- Department of Biological Sciences, San Jose State University, California 95192
| | | | - Alan Tran
- Department of Biological Sciences, San Jose State University, California 95192
| | - Wagner Steuer Costa
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Michelle C Krzyzanowski
- Department of Biological Sciences, University at Buffalo, The State University of New York, New York 14260
| | - Yanxun V Yu
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Chantal Brueggemann
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
| | - O Scott Hamilton
- Center for Neuroscience, University of California, Davis, California 95618
| | - Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, New York 14260
| | - Miri VanHoven
- Department of Biological Sciences, San Jose State University, California 95192
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Alexander Gottschalk
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Noelle L'Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
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208
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Kostyuk AI, Demidovich AD, Kotova DA, Belousov VV, Bilan DS. Circularly Permuted Fluorescent Protein-Based Indicators: History, Principles, and Classification. Int J Mol Sci 2019; 20:E4200. [PMID: 31461959 PMCID: PMC6747460 DOI: 10.3390/ijms20174200] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/22/2019] [Accepted: 08/24/2019] [Indexed: 12/28/2022] Open
Abstract
Genetically encoded biosensors based on fluorescent proteins (FPs) are a reliable tool for studying the various biological processes in living systems. The circular permutation of single FPs led to the development of an extensive class of biosensors that allow the monitoring of many intracellular events. In circularly permuted FPs (cpFPs), the original N- and C-termini are fused using a peptide linker, while new termini are formed near the chromophore. Such a structure imparts greater mobility to the FP than that of the native variant, allowing greater lability of the spectral characteristics. One of the common principles of creating genetically encoded biosensors is based on the integration of a cpFP into a flexible region of a sensory domain or between two interacting domains, which are selected according to certain characteristics. Conformational rearrangements of the sensory domain associated with ligand interaction or changes in the cellular parameter are transferred to the cpFP, changing the chromophore environment. In this review, we highlight the basic principles of such sensors, the history of their creation, and a complete classification of the available biosensors.
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Affiliation(s)
- Alexander I Kostyuk
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia
- Pirogov Russian National Research Medical University, Moscow 117997, Russia
| | | | - Daria A Kotova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia
| | - Vsevolod V Belousov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia
- Pirogov Russian National Research Medical University, Moscow 117997, Russia
- Institute for Cardiovascular Physiology, Georg August University Göttingen, D-37073 Göttingen, Germany
| | - Dmitry S Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia.
- Pirogov Russian National Research Medical University, Moscow 117997, Russia.
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209
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Penzkofer A, Silapetere A, Hegemann P. Absorption and Emission Spectroscopic Investigation of the Thermal Dynamics of the Archaerhodopsin 3 Based Fluorescent Voltage Sensor QuasAr1. Int J Mol Sci 2019; 20:E4086. [PMID: 31438573 PMCID: PMC6747118 DOI: 10.3390/ijms20174086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 12/13/2022] Open
Abstract
QuasAr1 is a fluorescent voltage sensor derived from Archaerhodopsin 3 (Arch) of Halorubrum sodomense by directed evolution. Here we report absorption and emission spectroscopic studies of QuasAr1 in Tris buffer at pH 8. Absorption cross-section spectra, fluorescence quantum distributions, fluorescence quantum yields, and fluorescence excitation spectra were determined. The thermal stability of QuasAr1 was studied by long-time attenuation coefficient measurements at room temperature (23 ± 2 °C) and at 2.5 ± 0.5 °C. The apparent melting temperature was determined by stepwise sample heating up and cooling down (obtained apparent melting temperature: 65 ± 3 °C). In the protein melting process the originally present protonated retinal Schiff base (PRSB) with absorption maximum at 580 nm converted to de-protonated retinal Schiff base (RSB) with absorption maximum at 380 nm. Long-time storage of QuasAr1 at temperatures around 2.5 °C and around 23 °C caused gradual protonated retinal Schiff base isomer changes to other isomer conformations, de-protonation to retinal Schiff base isomers, and apoprotein structure changes showing up in ultraviolet absorption increase. Reaction coordinate schemes are presented for the thermal protonated retinal Schiff base isomerizations and deprotonations in parallel with the dynamic apoprotein restructurings.
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Affiliation(s)
- Alfons Penzkofer
- Fakultät für Physik, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
| | - Arita Silapetere
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany
| | - Peter Hegemann
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany
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210
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Sardoiwala MN, Srivastava AK, Karmakar S, Roy Choudhury S. Nanostructure Endows Neurotherapeutic Potential in Optogenetics: Current Development and Future Prospects. ACS Chem Neurosci 2019; 10:3375-3385. [PMID: 31244053 DOI: 10.1021/acschemneuro.9b00246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Optogenetics have evolved as a promising tool to control the processes at a cellular level via photons. Specially, it confers a specific control over cellular function through real-time cytomodulation even in freely moving animals. Neuronal stimulation is prerequisite for deep tissue light penetration or insertion of optrode for light illumination to the neurons that have been proven to be compromised due to poor light penetration and invasiveness of the procedure, respectively. In this review, the application of nanotechnology is being elaborated by the use of metal nanoparticles (AuNPs), upconversion nanocrystals (UCNPs), and quantum dots (CdSe) for targeting particular organs or tissues, and their potential to emit a specific light on excitation to overcome the limitations associated with earlier methods has been elucidated. The optothermal and magnetothermal properties, photoluminescence, and higher photostability of nanomaterials are explored in context of therapeutic applicability of optogenetics. The nanostructure characteristics and specific ion channel targeting have shown promising therapeutic potential against neurodegenerative disorders (Alzheimer's, Parkinson's, Huntington's), epilepsy, and blindness. This review compiles mechanical and optical characteristics of nanomaterials that endow superior optogenetic therapeutic potentials to cure immedicable infirmities.
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Affiliation(s)
| | - Anup K. Srivastava
- Institute of Nano Science and Technology, Habitat Centre, Phase-10, Mohali, Punjab 160062, India
| | - Surajit Karmakar
- Institute of Nano Science and Technology, Habitat Centre, Phase-10, Mohali, Punjab 160062, India
| | - Subhasree Roy Choudhury
- Institute of Nano Science and Technology, Habitat Centre, Phase-10, Mohali, Punjab 160062, India
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211
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Optogenetics in Brain Research: From a Strategy to Investigate Physiological Function to a Therapeutic Tool. PHOTONICS 2019. [DOI: 10.3390/photonics6030092] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dissecting the functional roles of neuronal circuits and their interaction is a crucial step in basic neuroscience and in all the biomedical field. Optogenetics is well-suited to this purpose since it allows us to study the functionality of neuronal networks on multiple scales in living organisms. This tool was recently used in a plethora of studies to investigate physiological neuronal circuit function in addition to dysfunctional or pathological conditions. Moreover, optogenetics is emerging as a crucial technique to develop new rehabilitative and therapeutic strategies for many neurodegenerative diseases in pre-clinical models. In this review, we discuss recent applications of optogenetics, starting from fundamental research to pre-clinical applications. Firstly, we described the fundamental components of optogenetics, from light-activated proteins to light delivery systems. Secondly, we showed its applications to study neuronal circuits in physiological or pathological conditions at the cortical and subcortical level, in vivo. Furthermore, the interesting findings achieved using optogenetics as a therapeutic and rehabilitative tool highlighted the potential of this technique for understanding and treating neurological diseases in pre-clinical models. Finally, we showed encouraging results recently obtained by applying optogenetics in human neuronal cells in-vitro.
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212
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Rhodopsin-based voltage imaging tools for use in muscles and neurons of Caenorhabditis elegans. Proc Natl Acad Sci U S A 2019; 116:17051-17060. [PMID: 31371514 PMCID: PMC6708366 DOI: 10.1073/pnas.1902443116] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuronal and other excitable cell activity is characterized by alteration in membrane voltage, while intracellular Ca2+ levels and transmitter release are affected downstream of electrical activity. Thus, the most direct way of monitoring neuronal activity is by membrane voltage. Electrophysiology is demanding for multiple cells or cell ensembles and difficult to use in live animals, thus imaging methods are desirable. Yet, genetically encoded voltage indicators fell behind Ca2+ indicators until recently, when microbial rhodopsins and derivatives were introduced as genetically encoded voltage indicators. We evaluated rhodopsin tools for voltage imaging in muscles and neurons of Caenorhabditis elegans, a prime animal model in neuro- and cell biology, showing robust performance and the ability to characterize genetic mutants. Genetically encoded voltage indicators (GEVIs) based on microbial rhodopsins utilize the voltage-sensitive fluorescence of all-trans retinal (ATR), while in electrochromic FRET (eFRET) sensors, donor fluorescence drops when the rhodopsin acts as depolarization-sensitive acceptor. In recent years, such tools have become widely used in mammalian cells but are less commonly used in invertebrate systems, mostly due to low fluorescence yields. We systematically assessed Arch(D95N), Archon, QuasAr, and the eFRET sensors MacQ-mCitrine and QuasAr-mOrange, in the nematode Caenorhabditis elegans. ATR-bearing rhodopsins reported on voltage changes in body wall muscles (BWMs), in the pharynx, the feeding organ [where Arch(D95N) showed approximately 128% ΔF/F increase per 100 mV], and in neurons, integrating circuit activity. ATR fluorescence is very dim, yet, using the retinal analog dimethylaminoretinal, it was boosted 250-fold. eFRET sensors provided sensitivities of 45 to 78% ΔF/F per 100 mV, induced by BWM action potentials, and in pharyngeal muscle, measured in simultaneous optical and sharp electrode recordings, MacQ-mCitrine showed approximately 20% ΔF/F per 100 mV. All sensors reported differences in muscle depolarization induced by a voltage-gated Ca2+-channel mutant. Optogenetically evoked de- or hyperpolarization of motor neurons increased or eliminated action potential activity and caused a rise or drop in BWM sensor fluorescence. Finally, we analyzed voltage dynamics across the entire pharynx, showing uniform depolarization but compartmentalized repolarization of anterior and posterior parts. Our work establishes all-optical, noninvasive electrophysiology in live, intact C. elegans.
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213
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Subach OM, Barykina NV, Anokhin KV, Piatkevich KD, Subach FV. Near-Infrared Genetically Encoded Positive Calcium Indicator Based on GAF-FP Bacterial Phytochrome. Int J Mol Sci 2019; 20:ijms20143488. [PMID: 31315229 PMCID: PMC6678319 DOI: 10.3390/ijms20143488] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/09/2019] [Accepted: 07/15/2019] [Indexed: 02/01/2023] Open
Abstract
A variety of genetically encoded calcium indicators are currently available for visualization of calcium dynamics in cultured cells and in vivo. Only one of them, called NIR-GECO1, exhibits fluorescence in the near-infrared region of the spectrum. NIR-GECO1 is engineered based on the near-infrared fluorescent protein mIFP derived from bacterial phytochromes. However, NIR-GECO1 has an inverted response to calcium ions and its excitation spectrum is not optimal for the commonly used 640 nm lasers. Using small near-infrared bacterial phytochrome GAF-FP and calmodulin/M13-peptide pair, we developed a near-infrared calcium indicator called GAF-CaMP2. In vitro, GAF-CaMP2 showed a positive response of 78% and high affinity (Kd of 466 nM) to the calcium ions. It had excitation and emission maxima at 642 and 674 nm, respectively. GAF-CaMP2 had a 2.0-fold lower brightness, 5.5-fold faster maturation and lower pH stability compared to GAF-FP in vitro. GAF-CaMP2 showed 2.9-fold higher photostability than smURFP protein. The GAF-CaMP2 fusion with sfGFP demonstrated a ratiometric response with a dynamic range of 169% when expressed in the cytosol of mammalian cells in culture. Finally, we successfully applied the ratiometric version of GAF-CaMP2 for the simultaneous visualization of calcium transients in three organelles of mammalian cells using four-color fluorescence microscopy.
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Affiliation(s)
- Oksana M Subach
- National Research Center "Kurchatov Institute", Moscow 123182, Russia
| | | | - Konstantin V Anokhin
- P.K. Anokhin Institute of Normal Physiology, Moscow 125315, Russia
- Lomonosov Moscow State University, Moscow 119991, Russia
| | - Kiryl D Piatkevich
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA
| | - Fedor V Subach
- National Research Center "Kurchatov Institute", Moscow 123182, Russia.
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214
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Xu Q, Dong X. Calcium imaging approaches in investigation of pain mechanism in the spinal cord. Exp Neurol 2019; 317:129-132. [PMID: 30853387 PMCID: PMC6544469 DOI: 10.1016/j.expneurol.2019.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/16/2019] [Accepted: 03/06/2019] [Indexed: 11/28/2022]
Abstract
The continuous advancement of microscopic imaging techniques combined with the discovery and use of more powerful calcium indicators has made calcium imaging technology much more effective and has increased its use in the study of pain circuitry. Using calcium imaging to study spinal pain mechanisms causes less damage to animals compared to electrophysiological techniques and is also able to observe the firing pattern of spinal neurons and the connections between them on a large scale. These advantages allow any changes in spinal cord circuits caused by pain transmission to be observed more effectively. This review will discuss the development of calcium indicators over the past decades as well as the various applications of calcium imaging, from in vitro to in vivo spinal cord experiments, in the study of pain circuits. We will also discuss possible directions for the study of spinal pain circuits in the future.
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Affiliation(s)
- Qian Xu
- The Solomon H. Snyder Department of Neuroscience and the Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience and the Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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215
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Oh J, Lee C, Kaang BK. Imaging and analysis of genetically encoded calcium indicators linking neural circuits and behaviors. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2019; 23:237-249. [PMID: 31297008 PMCID: PMC6609268 DOI: 10.4196/kjpp.2019.23.4.237] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 12/21/2022]
Abstract
Confirming the direct link between neural circuit activity and animal behavior has been a principal aim of neuroscience. The genetically encoded calcium indicator (GECI), which binds to calcium ions and emits fluorescence visualizing intracellular calcium concentration, enables detection of in vivo neuronal firing activity. Various GECIs have been developed and can be chosen for diverse purposes. These GECI-based signals can be acquired by several tools including two-photon microscopy and microendoscopy for precise or wide imaging at cellular to synaptic levels. In addition, the images from GECI signals can be analyzed with open source codes including constrained non-negative matrix factorization for endoscopy data (CNMF_E) and miniscope 1-photon-based calcium imaging signal extraction pipeline (MIN1PIPE), and considering parameters of the imaged brain regions (e.g., diameter or shape of soma or the resolution of recorded images), the real-time activity of each cell can be acquired and linked with animal behaviors. As a result, GECI signal analysis can be a powerful tool for revealing the functions of neuronal circuits related to specific behaviors.
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Affiliation(s)
- Jihae Oh
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Chiwoo Lee
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Bong-Kiun Kaang
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
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216
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Zhong C, Schleifenbaum J. Genetically Encoded Calcium Indicators: A New Tool in Renal Hypertension Research. Front Med (Lausanne) 2019; 6:128. [PMID: 31263699 PMCID: PMC6585435 DOI: 10.3389/fmed.2019.00128] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/23/2019] [Indexed: 11/13/2022] Open
Abstract
Hypertension is ranked as the third cause of disability-adjusted life-years. The percentage of the population suffering from hypertension will continue to increase over the next years. Renovascular disease is one of the most common causes of secondary hypertension. Vascular changes seen in hypertension are partially based on dysfunctional calcium signaling. This signaling can be studied using calcium indicators (loading dyes and genetically encoded calcium indicators; GECIs). Most progress in development has been seen in GECIs, which are used in an increasing number of publications concerning calcium signaling in vasculature and the kidney. The use of transgenic mouse models expressing GECIs will facilitate new possibilities to study dysfunctional calcium signaling in a cell type-specific manner, thus helping to identify more specific targets for treatment of (renal) hypertension.
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Affiliation(s)
- Cheng Zhong
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Johanna Schleifenbaum
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
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217
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Nelson NA, Wang X, Cook D, Carey EM, Nimmerjahn A. Imaging spinal cord activity in behaving animals. Exp Neurol 2019; 320:112974. [PMID: 31175843 DOI: 10.1016/j.expneurol.2019.112974] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/02/2019] [Accepted: 06/04/2019] [Indexed: 01/06/2023]
Abstract
The spinal cord is the primary neurological link between the brain and peripheral organs. How important it is in everyday life is apparent in patients with spinal cord injury or motoneuron disease, who have dramatically reduced musculoskeletal control or capacity to sense their environment. Despite its crucial role in sensory and motor processing little is known about the cellular and molecular signaling events that underlie spinal cord function under naturalistic conditions. While genetic, electrophysiological, pharmacological, and circuit tracing studies have revealed important roles for different molecularly defined neurons, these approaches insufficiently describe the moment-to-moment neuronal and non-neuronal activity patterns that underlie sensory-guided motor behaviors in health and disease. The recent development of imaging methods for real-time interrogation of cellular activity in the spinal cord of behaving mice has removed longstanding technical obstacles to spinal cord research and allowed new insight into how different cell types encode sensory information from mechanoreceptors and nociceptors in the skin. Here, we review the current state-of-the-art in interrogating cellular and microcircuit function in the spinal cord of behaving mammals and discuss current opportunities and technological challenges.
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Affiliation(s)
- Nicholas A Nelson
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Biologial Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92037, USA
| | - Xiang Wang
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Daniela Cook
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Erin M Carey
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Axel Nimmerjahn
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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218
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Snyder AZ, Bauer AQ. Mapping Structure-Function Relationships in the Brain. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2019; 4:510-521. [PMID: 30528965 PMCID: PMC6488459 DOI: 10.1016/j.bpsc.2018.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 01/06/2023]
Abstract
Mapping the structural and functional connectivity of the brain is a major focus of systems neuroscience research and will help to identify causally important changes in neural circuitry responsible for behavioral dysfunction. Several methods for examining brain activity in humans have been extended to rodent and monkey models in which molecular and genetic manipulations exist for linking to human disease. In this review, which is part of a special issue focused on bridging brain connectivity information across species and spatiotemporal scales, we address mapping brain activity and neural connectivity in rodents using optogenetics in conjunction with either functional magnetic resonance imaging or optical intrinsic signal imaging. We chose to focus on these techniques because they are capable of reporting spontaneous or evoked hemodynamic activity most closely linked to human neuroimaging studies. We discuss the capabilities and limitations of blood-based imaging methods, usage of optogenetic techniques to map neural systems in rodent models, and other powerful mapping techniques for examining neural connectivity over different spatial and temporal scales. We also discuss implementing strategies for mapping brain connectivity in humans with both basic and clinical applications, and conclude with how cross-species mapping studies can be utilized to influence preclinical imaging studies and clinical practices alike.
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Affiliation(s)
- Abraham Z Snyder
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Adam Q Bauer
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri.
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219
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Guo C, Pan Y, Gong Z. Recent Advances in the Genetic Dissection of Neural Circuits in Drosophila. Neurosci Bull 2019; 35:1058-1072. [PMID: 31119647 DOI: 10.1007/s12264-019-00390-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/17/2018] [Indexed: 11/28/2022] Open
Abstract
Nervous systems endow animals with cognition and behavior. To understand how nervous systems control behavior, neural circuits mediating distinct functions need to be identified and characterized. With superior genetic manipulability, Drosophila is a model organism at the leading edge of neural circuit analysis. We briefly introduce the state-of-the-art genetic tools that permit precise labeling of neurons and their interconnectivity and investigating what is happening in the brain of a behaving animal and manipulating neurons to determine how behaviors are affected. Brain-wide wiring diagrams, created by light and electron microscopy, bring neural circuit analysis to a new level and scale. Studies enabled by these tools advances our understanding of the nervous system in relation to cognition and behavior.
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Affiliation(s)
- Chao Guo
- Key Laboratory of Developmental Genes and Human Disease of the Ministry of Education of China, Institute of Life Sciences, Southeast University, Nanjing, 210096, China.
| | - Yufeng Pan
- Key Laboratory of Developmental Genes and Human Disease of the Ministry of Education of China, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Zhefeng Gong
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China
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220
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Inoue M, Takeuchi A, Manita S, Horigane SI, Sakamoto M, Kawakami R, Yamaguchi K, Otomo K, Yokoyama H, Kim R, Yokoyama T, Takemoto-Kimura S, Abe M, Okamura M, Kondo Y, Quirin S, Ramakrishnan C, Imamura T, Sakimura K, Nemoto T, Kano M, Fujii H, Deisseroth K, Kitamura K, Bito H. Rational Engineering of XCaMPs, a Multicolor GECI Suite for In Vivo Imaging of Complex Brain Circuit Dynamics. Cell 2019; 177:1346-1360.e24. [PMID: 31080068 DOI: 10.1016/j.cell.2019.04.007] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/28/2019] [Accepted: 04/02/2019] [Indexed: 12/15/2022]
Abstract
To decipher dynamic brain information processing, current genetically encoded calcium indicators (GECIs) are limited in single action potential (AP) detection speed, combinatorial spectral compatibility, and two-photon imaging depth. To address this, here, we rationally engineered a next-generation quadricolor GECI suite, XCaMPs. Single AP detection was achieved within 3-10 ms of spike onset, enabling measurements of fast-spike trains in parvalbumin (PV)-positive interneurons in the barrel cortex in vivo and recording three distinct (two inhibitory and one excitatory) ensembles during pre-motion activity in freely moving mice. In vivo paired recording of pre- and postsynaptic firing revealed spatiotemporal constraints of dendritic inhibition in layer 1 in vivo, between axons of somatostatin (SST)-positive interneurons and apical tufts dendrites of excitatory pyramidal neurons. Finally, non-invasive, subcortical imaging using red XCaMP-R uncovered somatosensation-evoked persistent activity in hippocampal CA1 neurons. Thus, the XCaMPs offer a critical enhancement of solution space in studies of complex neuronal circuit dynamics. VIDEO ABSTRACT.
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Affiliation(s)
- Masatoshi Inoue
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Atsuya Takeuchi
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Satoshi Manita
- Department of Neurophysiology, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Shin-Ichiro Horigane
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Neuroscience I, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi 464-8601, Japan; Department of Molecular/Cellular Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Masayuki Sakamoto
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ryosuke Kawakami
- Laboratory of Molecular and Cellular Biophysics, Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan; Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan
| | - Kazushi Yamaguchi
- Laboratory of Molecular and Cellular Biophysics, Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan
| | - Kouhei Otomo
- Laboratory of Molecular and Cellular Biophysics, Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan
| | - Hiroyuki Yokoyama
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Ryang Kim
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tatsushi Yokoyama
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Sayaka Takemoto-Kimura
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Neuroscience I, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi 464-8601, Japan; Department of Molecular/Cellular Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan; Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Saitama, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Niigata 951-8585, Japan
| | - Michiko Okamura
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yayoi Kondo
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Sean Quirin
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Charu Ramakrishnan
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Takeshi Imamura
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Niigata 951-8585, Japan
| | - Tomomi Nemoto
- Laboratory of Molecular and Cellular Biophysics, Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; International Research Center for Neurointelligence, The University of Tokyo, Tokyo, Japan
| | - Hajime Fujii
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kazuo Kitamura
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Neurophysiology, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Haruhiko Bito
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; International Research Center for Neurointelligence, The University of Tokyo, Tokyo, Japan.
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221
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Gottschalk S, Degtyaruk O, Mc Larney B, Rebling J, Hutter MA, Deán-Ben XL, Shoham S, Razansky D. Rapid volumetric optoacoustic imaging of neural dynamics across the mouse brain. Nat Biomed Eng 2019; 3:392-401. [PMID: 30992553 PMCID: PMC6825512 DOI: 10.1038/s41551-019-0372-9] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 02/19/2019] [Indexed: 01/25/2023]
Abstract
Efforts to scale neuroimaging towards the direct visualization of mammalian brain-wide neuronal activity have faced major challenges. Although high-resolution optical imaging of the whole brain in small animals has been achieved ex vivo, the real-time and direct monitoring of large-scale neuronal activity remains difficult, owing to the performance gap between localized, largely invasive, optical microscopy of rapid, cellular-resolved neuronal activity and whole-brain macroscopy of slow haemodynamics and metabolism. Here, we demonstrate both ex vivo and non-invasive in vivo functional optoacoustic (OA) neuroimaging of mice expressing the genetically encoded calcium indicator GCaMP6f. The approach offers rapid, high-resolution three-dimensional snapshots of whole-brain neuronal activity maps using single OA excitations, and of stimulus-evoked slow haemodynamics and fast calcium activity in the presence of strong haemoglobin background absorption. By providing direct neuroimaging at depths and spatiotemporal resolutions superior to optical fluorescence imaging, functional OA neuroimaging bridges the gap between functional microscopy and whole-brain macroscopy.
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Affiliation(s)
- Sven Gottschalk
- Institute for Biological and Medical Imaging, Helmholtz Center Munich, Neuherberg, Germany
| | - Oleksiy Degtyaruk
- Institute for Biological and Medical Imaging, Helmholtz Center Munich, Neuherberg, Germany
| | - Benedict Mc Larney
- Institute for Biological and Medical Imaging, Helmholtz Center Munich, Neuherberg, Germany
- Faculty of Medicine, Technical University of Munich, Munich, Germany
| | - Johannes Rebling
- Institute for Biological and Medical Imaging, Helmholtz Center Munich, Neuherberg, Germany
- Faculty of Medicine, Technical University of Munich, Munich, Germany
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland
- Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Magdalena Anastasia Hutter
- Institute for Biological and Medical Imaging, Helmholtz Center Munich, Neuherberg, Germany
- Department of Electrical and Computer Engineering, Technical University of Munich, Munich, Germany
| | - Xosé Luís Deán-Ben
- Institute for Biological and Medical Imaging, Helmholtz Center Munich, Neuherberg, Germany
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland
- Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Shy Shoham
- Tech4Health Institute, New York University Langone Health, New York, NY, USA.
- Neuroscience Institute, New York University Langone Health, New York, NY, USA.
- Department of Ophthalmology, New York University Langone Health, New York, NY, USA.
| | - Daniel Razansky
- Institute for Biological and Medical Imaging, Helmholtz Center Munich, Neuherberg, Germany.
- Faculty of Medicine, Technical University of Munich, Munich, Germany.
- Faculty of Medicine, University of Zurich, Zurich, Switzerland.
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
- Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland.
- Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland.
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222
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Ca 2+-Stimulated AMPK-Dependent Phosphorylation of Exo1 Protects Stressed Replication Forks from Aberrant Resection. Mol Cell 2019; 74:1123-1137.e6. [PMID: 31053472 DOI: 10.1016/j.molcel.2019.04.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 02/04/2019] [Accepted: 03/29/2019] [Indexed: 12/22/2022]
Abstract
Abnormal processing of stressed replication forks by nucleases can cause fork collapse, genomic instability, and cell death. Despite its importance, it is poorly understood how the cell properly controls nucleases to prevent detrimental fork processing. Here, we report a signaling pathway that controls the activity of exonuclease Exo1 to prevent aberrant fork resection during replication stress. Our results indicate that replication stress elevates intracellular Ca2+ concentration ([Ca2+]i), leading to activation of CaMKK2 and the downstream kinase 5' AMP-activated protein kinase (AMPK). Following activation, AMPK directly phosphorylates Exo1 at serine 746 to promote 14-3-3 binding and inhibit Exo1 recruitment to stressed replication forks, thereby avoiding unscheduled fork resection. Disruption of this signaling pathway results in excessive ssDNA, chromosomal instability, and hypersensitivity to replication stress inducers. These findings reveal a link between [Ca2+]i and the replication stress response as well as a function of the Ca2+-CaMKK2-AMPK signaling axis in safeguarding fork structure to maintain genome stability.
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223
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DiLoreto EM, Chute CD, Bryce S, Srinivasan J. Novel Technological Advances in Functional Connectomics in C. elegans. J Dev Biol 2019; 7:E8. [PMID: 31018525 PMCID: PMC6630759 DOI: 10.3390/jdb7020008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/08/2019] [Accepted: 02/13/2019] [Indexed: 12/11/2022] Open
Abstract
The complete structure and connectivity of the Caenorhabditis elegans nervous system ("mind of a worm") was first published in 1986, representing a critical milestone in the field of connectomics. The reconstruction of the nervous system (connectome) at the level of synapses provided a unique perspective of understanding how behavior can be coded within the nervous system. The following decades have seen the development of technologies that help understand how neural activity patterns are connected to behavior and modulated by sensory input. Investigations on the developmental origins of the connectome highlight the importance of role of neuronal cell lineages in the final connectivity matrix of the nervous system. Computational modeling of neuronal dynamics not only helps reconstruct the biophysical properties of individual neurons but also allows for subsequent reconstruction of whole-organism neuronal network models. Hence, combining experimental datasets with theoretical modeling of neurons generates a better understanding of organismal behavior. This review discusses some recent technological advances used to analyze and perturb whole-organism neuronal function along with developments in computational modeling, which allows for interrogation of both local and global neural circuits, leading to different behaviors. Combining these approaches will shed light into how neural networks process sensory information to generate the appropriate behavioral output, providing a complete understanding of the worm nervous system.
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Affiliation(s)
- Elizabeth M DiLoreto
- Biology and Biotechnology Department, Worcester Polytechnic Institute, Worcester, MA 01605, USA.
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224
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Molina RS, Qian Y, Wu J, Shen Y, Campbell RE, Drobizhev M, Hughes TE. Understanding the Fluorescence Change in Red Genetically Encoded Calcium Ion Indicators. Biophys J 2019; 116:1873-1886. [PMID: 31054773 PMCID: PMC6531872 DOI: 10.1016/j.bpj.2019.04.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 03/02/2019] [Accepted: 04/02/2019] [Indexed: 12/17/2022] Open
Abstract
For over 20 years, genetically encoded Ca2+ indicators have illuminated dynamic Ca2+ signaling activity in living cells and, more recently, whole organisms. We are just now beginning to understand how they work. Various fluorescence colors of these indicators have been developed, including red. Red ones are promising because longer wavelengths of light scatter less in tissue, making it possible to image deeper. They are engineered from a red fluorescent protein that is circularly permuted and fused to a Ca2+-sensing domain. When Ca2+ binds, a conformational change in the sensing domain causes a change in fluorescence. Three factors can contribute to this fluorescence change: 1) a shift in the protonation equilibrium of the chromophore, 2) a change in fluorescence quantum yield, and 3) a change in the extinction coefficient or the two-photon cross section, depending on if it is excited with one or two photons. Here, we conduct a systematic study of the photophysical properties of a range of red Ca2+ indicators to determine which factors are the most important. In total, we analyzed nine indicators, including jRGECO1a, K-GECO1, jRCaMP1a, R-GECO1, R-GECO1.2, CAR-GECO1, O-GECO1, REX-GECO1, and a new variant termed jREX-GECO1. We find that these could be separated into three classes that each rely on a particular set of factors. Furthermore, in some cases, the magnitude of the change in fluorescence was larger with two-photon excitation compared to one-photon because of a change in the two-photon cross section, by up to a factor of two.
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Affiliation(s)
- Rosana S Molina
- Department of Cell Biology & Neuroscience, Montana State University, Bozeman, Montana
| | - Yong Qian
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jiahui Wu
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada; Department of Pharmacology, Weill Cornell Medicine, New York, New York
| | - Yi Shen
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Robert E Campbell
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada; Department of Chemistry, The University of Tokyo, Tokyo, Japan
| | - Mikhail Drobizhev
- Department of Cell Biology & Neuroscience, Montana State University, Bozeman, Montana
| | - Thomas E Hughes
- Department of Cell Biology & Neuroscience, Montana State University, Bozeman, Montana.
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225
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Wide-Area All-Optical Neurophysiology in Acute Brain Slices. J Neurosci 2019; 39:4889-4908. [PMID: 30952812 DOI: 10.1523/jneurosci.0168-19.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 03/15/2019] [Accepted: 04/01/2019] [Indexed: 11/21/2022] Open
Abstract
Optical tools for simultaneous perturbation and measurement of neural activity open the possibility of mapping neural function over wide areas of brain tissue. However, spectral overlap of actuators and reporters presents a challenge for their simultaneous use, and optical scattering and out-of-focus fluorescence in tissue degrade resolution. To minimize optical crosstalk, we combined an optimized variant (eTsChR) of the most blue-shifted channelrhodopsin reported to-date with a nuclear-localized red-shifted Ca2+ indicator, H2B-jRGECO1a. To perform wide-area optically sectioned imaging in tissue, we designed a structured illumination technique that uses Hadamard matrices to encode spatial information. By combining these molecular and optical approaches we made wide-area functional maps in acute brain slices from mice of both sexes. The maps spanned cortex and striatum and probed the effects of antiepileptic drugs on neural excitability and the effects of AMPA and NMDA receptor blockers on functional connectivity. Together, these tools provide a powerful capability for wide-area mapping of neuronal excitability and functional connectivity in acute brain slices.SIGNIFICANCE STATEMENT A new technique for simultaneous optogenetic stimulation and calcium imaging across wide areas of brain slice enables high-throughput mapping of neuronal excitability and synaptic transmission.
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226
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Ghanbari L, Carter RE, Rynes ML, Dominguez J, Chen G, Naik A, Hu J, Sagar MAK, Haltom L, Mossazghi N, Gray MM, West SL, Eliceiri KW, Ebner TJ, Kodandaramaiah SB. Cortex-wide neural interfacing via transparent polymer skulls. Nat Commun 2019; 10:1500. [PMID: 30940809 PMCID: PMC6445105 DOI: 10.1038/s41467-019-09488-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 03/12/2019] [Indexed: 11/22/2022] Open
Abstract
Neural computations occurring simultaneously in multiple cerebral cortical regions are critical for mediating behaviors. Progress has been made in understanding how neural activity in specific cortical regions contributes to behavior. However, there is a lack of tools that allow simultaneous monitoring and perturbing neural activity from multiple cortical regions. We engineered 'See-Shells'-digitally designed, morphologically realistic, transparent polymer skulls that allow long-term (>300 days) optical access to 45 mm2 of the dorsal cerebral cortex in the mouse. We demonstrate the ability to perform mesoscopic imaging, as well as cellular and subcellular resolution two-photon imaging of neural structures up to 600 µm deep. See-Shells allow calcium imaging from multiple, non-contiguous regions across the cortex. Perforated See-Shells enable introducing penetrating neural probes to perturb or record neural activity simultaneously with whole cortex imaging. See-Shells are constructed using common desktop fabrication tools, providing a powerful tool for investigating brain structure and function.
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Affiliation(s)
- Leila Ghanbari
- Department of Mechanical Engineering, University of Minnesota, Twin Cities, MN, USA
| | - Russell E Carter
- Department of Neuroscience, University of Minnesota, Twin Cities, MN, USA
| | - Mathew L Rynes
- Department of Biomedical Engineering, University of Minnesota, Twin Cities, MN, USA
| | - Judith Dominguez
- Department of Mechanical Engineering, University of Minnesota, Twin Cities, MN, USA
| | - Gang Chen
- Department of Neuroscience, University of Minnesota, Twin Cities, MN, USA
| | - Anant Naik
- Department of Biomedical Engineering, University of Minnesota, Twin Cities, MN, USA
| | - Jia Hu
- Department of Biomedical Engineering, University of Minnesota, Twin Cities, MN, USA
| | | | - Lenora Haltom
- Department of Mechanical Engineering, University of Minnesota, Twin Cities, MN, USA
| | - Nahom Mossazghi
- Department of Neuroscience, University of Minnesota, Twin Cities, MN, USA
| | - Madelyn M Gray
- Department of Neuroscience, University of Minnesota, Twin Cities, MN, USA
| | - Sarah L West
- Department of Neuroscience, University of Minnesota, Twin Cities, MN, USA
| | - Kevin W Eliceiri
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
| | - Timothy J Ebner
- Department of Neuroscience, University of Minnesota, Twin Cities, MN, USA
| | - Suhasa B Kodandaramaiah
- Department of Mechanical Engineering, University of Minnesota, Twin Cities, MN, USA.
- Department of Biomedical Engineering, University of Minnesota, Twin Cities, MN, USA.
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227
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Abstract
Understanding the mechanisms by which long-term synaptic plasticity is expressed remains an important objective in neuroscience. From a physiological perspective, the strength of a synapse can be considered a consequence of several parameters including the probability that a presynaptic action potential (AP) evokes the release of neurotransmitter, the mean number of quanta of transmitter released when release is evoked, and the mean amplitude of a postsynaptic response to a single quantum. Various methods have been employed to estimate these quantal parameters from electrophysiological recordings; such "quantal analysis" has been used to support competing accounts of mechanisms of expression of long-term plasticity. Because electrophysiological recordings, even with minimal presynaptic stimulation, can reflect responses arising at multiple synaptic sites, these methods are open to alternative interpretations. By combining intracellular electrical recording with optical detection of transmission at individual synapses, however, it is possible to eliminate such ambiguity. Here, we describe methods for such combined optical and electrical monitoring of synaptic transmission in brain slice preparations and illustrate how quantal analyses thereby obtained permit more definitive conclusions about the physiological changes that underlie long-term synaptic plasticity.
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Affiliation(s)
| | - Alan Fine
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
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228
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Kerruth S, Coates C, Dürst CD, Oertner TG, Török K. The kinetic mechanisms of fast-decay red-fluorescent genetically encoded calcium indicators. J Biol Chem 2019; 294:3934-3946. [PMID: 30651353 PMCID: PMC6422079 DOI: 10.1074/jbc.ra118.004543] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 01/14/2019] [Indexed: 01/06/2023] Open
Abstract
Genetically encoded calcium indicators (GECIs) are useful reporters of cell-signaling, neuronal, and network activities. We have generated novel fast variants and investigated the kinetic mechanisms of two recently developed red-fluorescent GECIs (RGECIs), mApple-based jRGECO1a and mRuby-based jRCaMP1a. In the formation of fluorescent jRGECO1a and jRCaMP1a complexes, calcium binding is followed by rate-limiting isomerization. However, fluorescence decay of calcium-bound jRGECO1a follows a different pathway from its formation: dissociation of calcium occurs first, followed by the peptide, similarly to GCaMP-s. In contrast, fluorescence decay of calcium-bound jRCaMP1a occurs by the reversal of the on-pathway: peptide dissociation is followed by calcium. The mechanistic differences explain the generally slower off-kinetics of jRCaMP1a-type indicators compared with GCaMP-s and jRGECO1a-type GECI: the fluorescence decay rate of f-RCaMP1 was 21 s-1, compared with 109 s-1 for f-RGECO1 and f-RGECO2 (37 °C). Thus, the CaM-peptide interface is an important determinant of the kinetic responses of GECIs; however, the topology of the structural link to the fluorescent protein demonstrably affects the internal dynamics of the CaM-peptide complex. In the dendrites of hippocampal CA3 neurons, f-RGECO1 indicates calcium elevation in response to a 100 action potential train in a linear fashion, making the probe particularly useful for monitoring large-amplitude, fast signals, e.g. those in dendrites, muscle cells, and immune cells.
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Affiliation(s)
- Silke Kerruth
- From the Molecular and Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, United Kingdom and
| | - Catherine Coates
- From the Molecular and Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, United Kingdom and
| | - Céline D Dürst
- the Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, 20251 Hamburg, Germany
| | - Thomas G Oertner
- the Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, 20251 Hamburg, Germany
| | - Katalin Török
- From the Molecular and Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, United Kingdom and
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229
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AMPK-mediated activation of MCU stimulates mitochondrial Ca 2+ entry to promote mitotic progression. Nat Cell Biol 2019; 21:476-486. [PMID: 30858581 DOI: 10.1038/s41556-019-0296-3] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 02/04/2019] [Indexed: 12/11/2022]
Abstract
The capacity of cells to alter bioenergetics in response to the demands of various biological processes is essential for normal physiology. The coordination of energy sensing and production with highly energy-demanding cellular processes, such as cell division, is poorly understood. Here, we show that a cell cycle-dependent mitochondrial Ca2+ transient connects energy sensing to mitochondrial activity for mitotic progression. The mitochondrial Ca2+ uniporter (MCU) mediates a rapid mitochondrial Ca2+ transient during mitosis. Inhibition of mitochondrial Ca2+ transients via MCU depletion causes spindle checkpoint-dependent mitotic delay. Cellular ATP levels drop during early mitosis, and the mitochondrial Ca2+ transients boost mitochondrial respiration to restore energy homeostasis. This is achieved through mitosis-specific MCU phosphorylation and activation by the mitochondrial translocation of energy sensor AMP-activated protein kinase (AMPK). Our results establish a critical role for AMPK- and MCU-dependent mitochondrial Ca2+ signalling in mitosis and reveal a mechanism of mitochondrial metabolic adaptation to acute cellular energy stress.
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230
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Soor NS, Quicke P, Howe CL, Pang KT, Neil MAA, Schultz SR, Foust AJ. All-optical crosstalk-free manipulation and readout of Chronos-expressing neurons. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2019; 52:104002. [PMID: 31057183 PMCID: PMC6466639 DOI: 10.1088/1361-6463/aaf944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 12/03/2018] [Accepted: 12/13/2018] [Indexed: 06/09/2023]
Abstract
All optical neurophysiology allows manipulation and readout of neural network activity with single-cell spatial resolution and millisecond temporal resolution. Neurons can be made to express proteins that actuate transmembrane currents upon light absorption, enabling optical control of membrane potential and action potential signalling. In addition, neurons can be genetically or synthetically labelled with fluorescent reporters of changes in intracellular calcium concentration or membrane potential. Thus, to optically manipulate and readout neural activity in parallel, two spectra are involved: the action spectrum of the actuator, and the absorption spectrum of the fluorescent reporter. Due to overlap in these spectra, previous all-optical neurophysiology paradigms have been hindered by spurious activation of neuronal activity caused by the readout light. Here, we pair the blue-green absorbing optogenetic actuator, Chronos, with a deep red-emitting fluorescent calcium reporter CaSiR-1. We show that cultured Chinese hamster ovary cells transfected with Chronos do not exhibit transmembrane currents when illuminated with wavelengths and intensities suitable for exciting one-photon CaSiR-1 fluorescence. We then demonstrate crosstalk-free, high signal-to-noise ratio CaSiR-1 red fluorescence imaging at 100 frames s-1 of Chronos-mediated calcium transients evoked in neurons with blue light pulses at rates up to 20 Hz. These results indicate that the spectral separation between red light excited fluorophores, excited efficiently at or above 640 nm, with blue-green absorbing opsins such as Chronos, is sufficient to avoid spurious opsin actuation by the imaging wavelengths and therefore enable crosstalk-free all-optical neuronal manipulation and readout.
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Affiliation(s)
- Navjeevan S Soor
- Centre for Neurotechnology, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Peter Quicke
- Centre for Neurotechnology, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Carmel L Howe
- Centre for Neurotechnology, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Kuin T Pang
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (ASTAR), Singapore
| | - Mark A A Neil
- Department of Physics, Blackett Laboratory, Imperial College London, London, United Kingdom
| | - Simon R Schultz
- Centre for Neurotechnology, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Amanda J Foust
- Centre for Neurotechnology, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
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231
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pyPhotometry: Open source Python based hardware and software for fiber photometry data acquisition. Sci Rep 2019; 9:3521. [PMID: 30837543 PMCID: PMC6401057 DOI: 10.1038/s41598-019-39724-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/27/2018] [Indexed: 12/25/2022] Open
Abstract
Fiber photometry is the process of recording bulk neural activity by measuring fluorescence changes in activity sensitive indicators such as GCaMP through an optical fiber. We present a system of open source hardware and software for fiber photometry data acquisition consisting of a compact, low cost, data acquisition board built around the Micropython microcontroller, and a cross platform graphical user interface (GUI) for controlling acquisition and visualising signals. The system can acquire two analog and two digital signals, and control two external LEDs via built in LED drivers. Time-division multiplexed illumination allows independent readout of fluorescence evoked by different excitation wavelengths from a single photoreceiver signal. Validation experiments indicate this approach offers better signal to noise for a given average excitation light intensity than sinusoidally-modulated illumination. pyPhotometry is substantially cheaper than commercial hardware filling the same role, and we anticipate, as an open source and comparatively simple tool, it will be easily adaptable and therefore of broad interest to a wide range of users.
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232
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Anderson HE, Weir RFF. On the development of optical peripheral nerve interfaces. Neural Regen Res 2019; 14:425-436. [PMID: 30539808 PMCID: PMC6334609 DOI: 10.4103/1673-5374.245461] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 09/19/2018] [Indexed: 11/04/2022] Open
Abstract
Limb loss and spinal cord injury are two debilitating conditions that continue to grow in prevalence. Prosthetic limbs and limb reanimation present two ways of providing affected individuals with means to interact in the world. These techniques are both dependent on a robust interface with the peripheral nerve. Current methods for interfacing with the peripheral nerve tend to suffer from low specificity, high latency and insufficient robustness for a chronic implant. An optical peripheral nerve interface may solve some of these problems by decreasing invasiveness and providing single axon specificity. In order to implement such an interface three elements are required: (1) a transducer capable of translating light into a neural stimulus or translating neural activity into changes in fluorescence, (2) a means for delivering said transducer and (3) a microscope for providing the stimulus light and detecting the fluorescence change. There are continued improvements in both genetically encoded calcium and voltage indicators as well as new optogenetic actuators for stimulation. Similarly, improvements in specificity of viral vectors continue to improve expression in the axons of the peripheral nerve. Our work has recently shown that it is possible to virally transduce axons of the peripheral nerve for recording from small fibers. The improvements of these components make an optical peripheral nerve interface a rapidly approaching alternative to current methods.
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Affiliation(s)
- Hans E. Anderson
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
| | - Richard F. ff. Weir
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
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233
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Hu C, Sam R, Shan M, Nastasa V, Wang M, Kim T, Gillette M, Sengupta P, Popescu G. Optical excitation and detection of neuronal activity. JOURNAL OF BIOPHOTONICS 2019; 12:e201800269. [PMID: 30311744 DOI: 10.1002/jbio.201800269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 10/09/2018] [Indexed: 05/23/2023]
Abstract
Optogenetics has emerged as an exciting tool for manipulating neural activity, which in turn, can modulate behavior in live organisms. However, detecting the response to the optical stimulation requires electrophysiology with physical contact or fluorescent imaging at target locations, which is often limited by photobleaching and phototoxicity. In this paper, we show that phase imaging can report the intracellular transport induced by optogenetic stimulation. We developed a multimodal instrument that can both stimulate cells with subcellular spatial resolution and detect optical pathlength (OPL) changes with nanometer scale sensitivity. We found that OPL fluctuations following stimulation are consistent with active organelle transport. Furthermore, the results indicate a broadening in the transport velocity distribution, which is significantly higher in stimulated cells compared to optogenetically inactive cells. It is likely that this label-free, contactless measurement of optogenetic response will provide an enabling approach to neuroscience.
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Affiliation(s)
- Chenfei Hu
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Richard Sam
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Mingguang Shan
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- College of Information and Communication Engineering, Harbin Engineering University, Harbin, Heilongjiang, China
| | - Viorel Nastasa
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- National Institute for Laser Plasma and Radiation Physics, Bucharest, Ilfov, Romania
| | - Minqi Wang
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Taewoo Kim
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Martha Gillette
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Parijat Sengupta
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Gabriel Popescu
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
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234
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Sato R, Kawashima R, Trinh MDL, Nakano M, Nagai T, Masuda S. Significance of PGR5-dependent cyclic electron flow for optimizing the rate of ATP synthesis and consumption in Arabidopsis chloroplasts. PHOTOSYNTHESIS RESEARCH 2019; 139:359-365. [PMID: 29916043 DOI: 10.1007/s11120-018-0533-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 06/09/2018] [Indexed: 05/11/2023]
Abstract
The proton motive force (PMF) across the chloroplast thylakoid membrane that is generated by electron transport during photosynthesis is the driving force for ATP synthesis in plants. The PMF mainly arises from the oxidation of water in photosystem II and from electron transfer within the cytochrome b6f complex. There are two electron transfer pathways related to PMF formation: linear electron flow and cyclic electron flow. Proton gradient regulation 5 (PGR5) is a major component of the cyclic electron flow pathway, and the Arabidopsis pgr5 mutant shows a substantial reduction in the PMF. How the PGR5-dependent cyclic electron flow contributes to ATP synthesis has not, however, been fully delineated. In this study, we monitored in vivo ATP levels in Arabidopsis chloroplasts in real time using a genetically encoded bioluminescence-based ATP indicator, Nano-lantern(ATP1). The increase in ATP in the chloroplast stroma of pgr5 leaves upon illumination with actinic light was significantly slower than in wild type, and the decrease in ATP levels when this illumination stopped was significantly faster in pgr5 leaves than in wild type. These results indicated that PGR5-dependent cyclic electron flow around photosystem I helps to sustain the rate of ATP synthesis, which is important for growth under fluctuating light conditions.
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Affiliation(s)
- Ryoichi Sato
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, 444-8585, Japan
| | - Rinya Kawashima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
| | - Mai Duy Luu Trinh
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
| | - Masahiro Nakano
- The Institute of Scientific and Industrial Research, Osaka University, Osaka, 567-0047, Japan
| | - Takeharu Nagai
- The Institute of Scientific and Industrial Research, Osaka University, Osaka, 567-0047, Japan
| | - Shinji Masuda
- Center for Biological Resources & Informatics, Tokyo Institute of Technology, Yokohama, 226-8501, Japan.
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235
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In-Vitro Characterization of mCerulean3_mRuby3 as a Novel FRET Pair with Favorable Bleed-Through Characteristics. BIOSENSORS-BASEL 2019; 9:bios9010033. [PMID: 30823443 PMCID: PMC6468510 DOI: 10.3390/bios9010033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/12/2019] [Accepted: 02/19/2019] [Indexed: 11/28/2022]
Abstract
In previous studies, we encountered substantial problems using the CFP_YFP Förster resonance energy transfer (FRET) pair to analyze protein proximity in the endoplasmic reticulum of live cells. Bleed-through of the donor emission into the FRET channel and overlap of the FRET emission wavelength with highly variable cellular autofluorescence significantly compromised the sensitivity of our analyses. Here, we propose mCerulean3 and mRuby3 as a new FRET pair to potentially overcome these problems. Fusion of the two partners with a trypsin-cleavable linker allowed the direct comparison of the FRET signal characteristics of the associated partners with those of the completely dissociated partners. We compared our new FRET pair with the canonical CFP_YFP and the more recent mClover3_mRuby3 pairs and found that, despite a lower total FRET signal intensity, the novel pair had a significantly better signal to noise ratio due to lower donor emission bleed-through. This and the fact that the mRuby3 emission spectrum did not overlap with that of common cellular autofluorescence renders the mCerulean3_mRuby3 FRET pair a promising alternative to the common CFP_YFP FRET pair for the interaction analysis of membrane proteins in living cells.
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236
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Gong C, Ouyang Z, Zhao W, Wang J, Li K, Zhou P, Zhao T, Zheng N, Gong Z. A Neuronal Pathway that Commands Deceleration in Drosophila Larval Light-Avoidance. Neurosci Bull 2019; 35:959-968. [PMID: 30810958 DOI: 10.1007/s12264-019-00349-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 12/26/2018] [Indexed: 01/09/2023] Open
Abstract
When facing a sudden danger or aversive condition while engaged in on-going forward motion, animals transiently slow down and make a turn to escape. The neural mechanisms underlying stimulation-induced deceleration in avoidance behavior are largely unknown. Here, we report that in Drosophila larvae, light-induced deceleration was commanded by a continuous neural pathway that included prothoracicotropic hormone neurons, eclosion hormone neurons, and tyrosine decarboxylase 2 motor neurons (the PET pathway). Inhibiting neurons in the PET pathway led to defects in light-avoidance due to insufficient deceleration and head casting. On the other hand, activation of PET pathway neurons specifically caused immediate deceleration in larval locomotion. Our findings reveal a neural substrate for the emergent deceleration response and provide a new understanding of the relationship between behavioral modules in animal avoidance responses.
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Affiliation(s)
- Caixia Gong
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Zhenhuan Ouyang
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, 310007, China
| | - Weiqiao Zhao
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jie Wang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Kun Li
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Peipei Zhou
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Ting Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 22011, USA
| | - Nenggan Zheng
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, 310007, China.
| | - Zhefeng Gong
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
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237
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Kannan M, Vasan G, Pieribone VA. Optimizing Strategies for Developing Genetically Encoded Voltage Indicators. Front Cell Neurosci 2019; 13:53. [PMID: 30863283 PMCID: PMC6399427 DOI: 10.3389/fncel.2019.00053] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 02/04/2019] [Indexed: 01/23/2023] Open
Abstract
Genetically encoded optical indicators of neuronal activity enable unambiguous recordings of input-output activity patterns from identified cells in intact circuits. Among them, genetically encoded voltage indicators (GEVIs) offer additional advantages over calcium indicators as they are direct sensors of membrane potential and can adeptly report subthreshold events and hyperpolarization. Here, we outline the major GEVI designs and give an account of properties that need to be carefully optimized during indicator engineering. While designing the ideal GEVI, one should keep in mind aspects such as membrane localization, signal size, signal-to-noise ratio, kinetics and voltage dependence of optical responses. Using ArcLight and derivatives as prototypes, we delineate how a probe should be optimized for the former properties and developed along other areas in a need-based manner. Finally, we present an overview of the GEVI engineering process and lend an insight into their discovery, delivery and diagnosis.
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Affiliation(s)
- Madhuvanthi Kannan
- The John B. Pierce Laboratory, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Ganesh Vasan
- The John B. Pierce Laboratory, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Vincent A Pieribone
- The John B. Pierce Laboratory, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Neuroscience, Yale School of Medicine, Yale University, New Haven, CT, United States
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238
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Sundukova M, Prifti E, Bucci A, Kirillova K, Serrao J, Reymond L, Umebayashi M, Hovius R, Riezman H, Johnsson K, Heppenstall PA. A Chemogenetic Approach for the Optical Monitoring of Voltage in Neurons. Angew Chem Int Ed Engl 2019; 58:2341-2344. [PMID: 30569539 PMCID: PMC6391943 DOI: 10.1002/anie.201812967] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/16/2018] [Indexed: 01/11/2023]
Abstract
Optical monitoring of neuronal voltage using fluorescent indicators is a powerful approach for the interrogation of the cellular and molecular logic of the nervous system. Herein, a semisynthetic tethered voltage indicator (STeVI1) based upon nile red is described that displays voltage sensitivity when genetically targeted to neuronal membranes. This environmentally sensitive probe allows for wash-free imaging and faithfully detects supra- and sub-threshold activity in neurons.
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Affiliation(s)
- Mayya Sundukova
- Molecular Medicine Partnership Unit (MMPU)69117HeidelbergGermany
- Epigenetics and Neurobiology UnitEMBL Romevia Ramarini 32MonterotondoItaly
| | - Efthymia Prifti
- Molecular Medicine Partnership Unit (MMPU)69117HeidelbergGermany
- Epigenetics and Neurobiology UnitEMBL Romevia Ramarini 32MonterotondoItaly
| | - Annalisa Bucci
- Molecular Medicine Partnership Unit (MMPU)69117HeidelbergGermany
- Epigenetics and Neurobiology UnitEMBL Romevia Ramarini 32MonterotondoItaly
| | - Kseniia Kirillova
- Molecular Medicine Partnership Unit (MMPU)69117HeidelbergGermany
- Epigenetics and Neurobiology UnitEMBL Romevia Ramarini 32MonterotondoItaly
| | - Joana Serrao
- Molecular Medicine Partnership Unit (MMPU)69117HeidelbergGermany
- Epigenetics and Neurobiology UnitEMBL Romevia Ramarini 32MonterotondoItaly
| | - Luc Reymond
- Ecole Polytechnique Federale de LausanneISICNational Centre for Competence in Research (NCCR) in Chemical Biology1015LausanneSwitzerland
| | - Miwa Umebayashi
- University of GenevaDepartment of Biochemistry, National Centre for Competence in Research (NCCR) in Chemical Biology1211GenevaSwitzerland
| | - Ruud Hovius
- Ecole Polytechnique Federale de LausanneISICNational Centre for Competence in Research (NCCR) in Chemical Biology1015LausanneSwitzerland
| | - Howard Riezman
- University of GenevaDepartment of Biochemistry, National Centre for Competence in Research (NCCR) in Chemical Biology1211GenevaSwitzerland
| | - Kai Johnsson
- Department of Chemical BiologyMax Planck Institute for Medical Research69120HeidelbergGermany
- Ecole Polytechnique Federale de LausanneISICNational Centre for Competence in Research (NCCR) in Chemical Biology1015LausanneSwitzerland
| | - Paul A. Heppenstall
- Molecular Medicine Partnership Unit (MMPU)69117HeidelbergGermany
- Epigenetics and Neurobiology UnitEMBL Romevia Ramarini 32MonterotondoItaly
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239
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Advances in Engineering and Application of Optogenetic Indicators for Neuroscience. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9030562] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Our ability to investigate the brain is limited by available technologies that can record biological processes in vivo with suitable spatiotemporal resolution. Advances in optogenetics now enable optical recording and perturbation of central physiological processes within the intact brains of model organisms. By monitoring key signaling molecules noninvasively, we can better appreciate how information is processed and integrated within intact circuits. In this review, we describe recent efforts engineering genetically-encoded fluorescence indicators to monitor neuronal activity. We summarize recent advances of sensors for calcium, potassium, voltage, and select neurotransmitters, focusing on their molecular design, properties, and current limitations. We also highlight impressive applications of these sensors in neuroscience research. We adopt the view that advances in sensor engineering will yield enduring insights on systems neuroscience. Neuroscientists are eager to adopt suitable tools for imaging neural activity in vivo, making this a golden age for engineering optogenetic indicators.
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240
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Siciliano CA, Tye KM. Leveraging calcium imaging to illuminate circuit dysfunction in addiction. Alcohol 2019; 74:47-63. [PMID: 30470589 PMCID: PMC7575247 DOI: 10.1016/j.alcohol.2018.05.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/08/2018] [Accepted: 05/28/2018] [Indexed: 12/28/2022]
Abstract
Alcohol and drug use can dysregulate neural circuit function to produce a wide range of neuropsychiatric disorders, including addiction. To understand the neural circuit computations that mediate behavior, and how substances of abuse may transform them, we must first be able to observe the activity of circuits. While many techniques have been utilized to measure activity in specific brain regions, these regions are made up of heterogeneous sub-populations, and assessing activity from neuronal populations of interest has been an ongoing challenge. To fully understand how neural circuits mediate addiction-related behavior, we must be able to reveal the cellular granularity within brain regions and circuits by overlaying functional information with the genetic and anatomical identity of the cells involved. The development of genetically encoded calcium indicators, which can be targeted to populations of interest, allows for in vivo visualization of calcium dynamics, a proxy for neuronal activity, thus providing an avenue for real-time assessment of activity in genetically and anatomically defined populations during behavior. Here, we highlight recent advances in calcium imaging technology, compare the current technology with other state-of-the-art approaches for in vivo monitoring of neural activity, and discuss the strengths, limitations, and practical concerns for observing neural circuit activity in preclinical addiction models.
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Affiliation(s)
- Cody A Siciliano
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
| | - Kay M Tye
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; The Salk Institute for Biological Sciences, 10010 N Torrey Pines Road, La Jolla, CA 92037, United States.
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241
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Jáidar O, Carrillo-Reid L, Nakano Y, Lopez-Huerta VG, Hernandez-Cruz A, Bargas J, Garcia-Munoz M, Arbuthnott GW. Synchronized activation of striatal direct and indirect pathways underlies the behavior in unilateral dopamine-depleted mice. Eur J Neurosci 2019; 49:1512-1528. [PMID: 30633847 PMCID: PMC6767564 DOI: 10.1111/ejn.14344] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 12/17/2018] [Accepted: 12/25/2018] [Indexed: 11/27/2022]
Abstract
For more than three decades it has been known, that striatal neurons become hyperactive after the loss of dopamine input, but the involvement of dopamine (DA) D1‐ or D2‐receptor‐expressing neurons has only been demonstrated indirectly. By recording neuronal activity using fluorescent calcium indicators in D1 or D2 eGFP‐expressing mice, we showed that following dopamine depletion, both types of striatal output neurons are involved in the large increase in neuronal activity generating a characteristic cell assembly of particular neurons that dominate the pattern. When we expressed channelrhodopsin in all the output neurons, light activation in freely moving animals, caused turning like that following dopamine loss. However, if the light stimulation was patterned in pulses the animals circled in the other direction. To explore the neuronal participation during this stimulation we infected normal mice with channelrhodopsin and calcium indicator in striatal output neurons. In slices made from these animals, continuous light stimulation for 15 s induced many cells to be active together and a particular dominant group of neurons, whereas light in patterned pulses activated fewer cells in more variable groups. These results suggest that the simultaneous activity of a large dominant group of striatal output neurons is intimately associated with parkinsonian symptoms.
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Affiliation(s)
- Omar Jáidar
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Luis Carrillo-Reid
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Yoko Nakano
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | | | | | - José Bargas
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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242
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Vicario M, Calì T. Measuring Ca 2+ Levels in Subcellular Compartments with Genetically Encoded GFP-Based Indicators. Methods Mol Biol 2019; 1925:31-42. [PMID: 30674014 DOI: 10.1007/978-1-4939-9018-4_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Ca2+ homeostasis is crucial for the entire life of eukaryotic cells from the beginning to the end. Mishandling in Ca2+ homeostasis is indeed linked with a large number of pathological conditions. Thus, the possibility to specifically monitor cellular calcium fluxes in different subcellular compartments represents a key tool to deeply understand the mechanisms involved in cellular dysfunctions. To cope with this need, several Ca2+ indicators have been developed allowing to accurately measure both basal Ca2+ concentration and agonist-induced Ca2+ signals in a wide spectrum of organelles. Among these, the genetically encoded GFP-based indicators are routinely used to measure Ca2+ transients thanks to their ability to change their spectral properties in response to Ca2+ binding. In this chapter, we will describe a protocol that utilizes the GCaMP6f probe targeted to mitochondria (4mtGCaMP) to measure mitochondrial calcium levels in resting conditions in HeLa cells. This method allows to easily and quickly register alterations of mitochondrial Ca2+ homeostasis in different cell populations and experimental settings, representing a precious tool to unravel the pathological pathways leading to pathogenic conditions.
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Affiliation(s)
- Mattia Vicario
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Tito Calì
- Department of Biomedical Sciences, University of Padua, Padua, Italy.
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243
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Wang W, Kim CK, Ting AY. Molecular tools for imaging and recording neuronal activity. Nat Chem Biol 2019; 15:101-110. [PMID: 30659298 DOI: 10.1038/s41589-018-0207-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 11/20/2018] [Indexed: 11/09/2022]
Abstract
To understand how the brain relates to behavior, it is essential to record neural activity in awake, behaving animals. To achieve this goal, a large variety of genetically encoded sensors have been developed to monitor and record the series of events following neuronal firing, including action potentials, intracellular calcium rise, neurotransmitter release and immediate early gene expression. In this Review, we discuss the existing genetically encoded tools for detecting and integrating neuronal activity in animals and highlight the remaining challenges and future opportunities for molecular biologists.
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Affiliation(s)
- Wenjing Wang
- Departments of Genetics, Biology, and Chemistry, Stanford University, Stanford, CA, USA.,Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.,Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Christina K Kim
- Departments of Genetics, Biology, and Chemistry, Stanford University, Stanford, CA, USA
| | - Alice Y Ting
- Departments of Genetics, Biology, and Chemistry, Stanford University, Stanford, CA, USA. .,Chan Zuckerberg Biohub, San Francisco, CA, USA.
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244
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Davies SA, Cabrero P, Marley R, Corrales GM, Ghimire S, Dornan AJ, Dow JAT. Epithelial Function in the Drosophila Malpighian Tubule: An In Vivo Renal Model. Methods Mol Biol 2019; 1926:203-221. [PMID: 30742274 DOI: 10.1007/978-1-4939-9021-4_17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The insect renal (Malpighian) tubule has long been a model system for the study of fluid secretion and its neurohormonal control, as well as studies on ion transport mechanisms. To extend these studies beyond the boundaries of classical physiology, a molecular genetic approach together with the 'omics technologies is required. To achieve this in any vertebrate transporting epithelium remains a daunting task, as the genetic tools available are still relatively unsophisticated. Drosophila melanogaster, however, is an outstanding model organism for molecular genetics. Here we describe a technique for fluid secretion assays in the D. melanogaster equivalent of the kidney nephron. The development of this first physiological assay for a Drosophila epithelium, allowing combined approaches of integrative physiology and functional genomics, has now provided biologists with an entirely new model system, the Drosophila Malpighian tubule, which is utilized in multiple fields as diverse as kidney disease research and development of new modes of pest insect control.
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Affiliation(s)
- Shireen-A Davies
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK.
| | - Pablo Cabrero
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Richard Marley
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Guillermo Martinez Corrales
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Saurav Ghimire
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Anthony J Dornan
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Julian A T Dow
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK.
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245
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Benskey MJ, Sandoval IM, Miller K, Sellnow RL, Gezer A, Kuhn NC, Vashon R, Manfredsson FP. Basic Concepts in Viral Vector-Mediated Gene Therapy. Methods Mol Biol 2019; 1937:3-26. [PMID: 30706387 DOI: 10.1007/978-1-4939-9065-8_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Today any researcher with the desire can easily purchase a viral vector. However, despite the availability of viral vectors themselves, the requisite knowledge that is absolutely essential to conducting a gene therapy experiment remains somewhat obscure and esoteric. To utilize viral vectors to their full potential, a large number of decisions must be made, in some instances prior to even obtaining the vector itself. For example, critical decisions include selection of the proper virus, selection of the proper expression cassette, whether to produce or purchase a viral vector, proper viral handling and storage, the most appropriate delivery method, selecting the proper controls, how to ensure your virus is expressing properly, and many other complex decisions that are essential to performing a successful gene therapy experiment. The need to make so many important decisions can be overwhelming and potentially prohibitive, especially to the novice gene therapist. In order to aid in this challenging process, here we provide an overview of basic gene therapy modalities and a decision tree that can be used to make oneself aware of the options available to the beginning gene therapist. This information can be used as a road map to help navigate the complex and perhaps confusing process of designing a successful gene therapy experiment.
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Affiliation(s)
- Matthew J Benskey
- Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Ivette M Sandoval
- Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI, USA
- Mercy Health Saint Mary's, Grand Rapids, MI, USA
| | - Kathryn Miller
- Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Rhyomi L Sellnow
- Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Aysegul Gezer
- Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Nathan C Kuhn
- Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Roslyn Vashon
- Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Fredric P Manfredsson
- Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI, USA.
- Mercy Health Saint Mary's, Grand Rapids, MI, USA.
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246
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Owen SF, Kreitzer AC. An open-source control system for in vivo fluorescence measurements from deep-brain structures. J Neurosci Methods 2019; 311:170-177. [PMID: 30342106 PMCID: PMC6258340 DOI: 10.1016/j.jneumeth.2018.10.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/26/2018] [Accepted: 10/16/2018] [Indexed: 11/17/2022]
Abstract
BACKGROUND Intracranial photometry through chronically implanted optical fibers is a widely adopted technique for measuring signals from fluorescent probes in deep-brain structures. The recent proliferation of bright, photo-stable, and specific genetically encoded fluorescent reporters for calcium and for other neuromodulators has greatly increased the utility and popularity of this technique. NEW METHOD Here we describe an open-source, cost-effective, microcontroller-based solution for controlling optical components in an intracranial photometry system and processing the resulting signal. RESULTS We show proof-of-principle that this system supports high quality intracranial photometry recordings from dorsal striatum in freely moving mice. A single system supports simultaneous fluorescence measurements in two independent color channels, but multiple systems can be integrated together if additional fluorescence channels are required. This system is designed to work in combination with either commercially available or custom-built optical components. Parts can be purchased for less than one tenth the cost of commercially available alternatives and complete assembly takes less than one day for an inexperienced user. COMPARISON WITH EXISTING METHOD(S) Currently available hardware draws on a variety of commercial, custom-built, or hybrid elements for both optical and electronic components. Many of these hardware systems are either specialized and inflexible, or over-engineered and expensive. CONCLUSIONS This open-source system increases experimental flexibility while reducing cost relative to current commercially available components. All software and firmware are open-source and customizable, affording a degree of experimental flexibility that is not available in current commercial systems.
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Affiliation(s)
| | - Anatol C Kreitzer
- Gladstone Institutes, United States; Department of Neurology, UCSF, United states; Kavli Institute for Fundamental Neuroscience, United States; UCSF Weill Institute for Neurosciences, United States; Department of Physiology, UCSF, United States
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247
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The Astrocyte-Neuron Interface: An Overview on Molecular and Cellular Dynamics Controlling Formation and Maintenance of the Tripartite Synapse. Methods Mol Biol 2019; 1938:3-18. [PMID: 30617969 DOI: 10.1007/978-1-4939-9068-9_1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Astrocytes are known to provide trophic support to neurons and were originally thought to be passive space-filling cells in the brain. However, recent advances in astrocyte development and functions have highlighted their active roles in controlling brain functions by modulating synaptic transmission. A bidirectional cross talk between astrocytic processes and neuronal synapses define the concept of tripartite synapse. Any change in astrocytic structure/function influences neuronal activity which could lead to neurodevelopmental and neurodegenerative disorders. In this chapter, we briefly overview the methodologies used in deciphering the mechanisms of dynamic interplay between astrocytes and neurons.
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248
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Huang C, Gu Y, Chen J, Bahrani AA, Abu Jawdeh EG, Bada HS, Saatman K, Yu G, Chen L. A Wearable Fiberless Optical Sensor for Continuous Monitoring of Cerebral Blood Flow in Mice. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS : A PUBLICATION OF THE IEEE LASERS AND ELECTRO-OPTICS SOCIETY 2019; 25:1-9. [PMID: 31666792 DOI: 10.1109/jstqe.2018.2869613] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Continuous and longitudinal monitoring of cerebral blood flow (CBF) in animal models provides information for studying the mechanisms and interventions of various cerebral diseases. Since anesthesia may affect brain hemodynamics, researchers have been seeking wearable devices for use in conscious animals. We present a wearable diffuse speckle contrast flowmeter (DSCF) probe for monitoring CBF variations in mice. The DSCF probe consists of a small low-power near-infrared laser diode as a point source and an ultra-small low-power CMOS camera as a 2D detector array, which can be affixed on a mouse head. The movement of red blood cells in brain cortex (i.e., CBF) produces spatial fluctuations of laser speckles, which are captured by the camera. The DSCF system was calibrated using tissue phantoms and validated in a human forearm and mouse brains for continuous monitoring of blood flow increases and decreases against the established technologies. Significant correlations were observed among these measurements (R2 ≥ 0.80, p < 10-5). This small fiberless probe has the potential to be worn by a freely moving conscious mouse. Moreover, the flexible source-detector configuration allows for varied probing depths up to ~8 mm, which is sufficient for transcranially detecting CBF in the cortices of rodents and newborn infants.
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Affiliation(s)
- Chong Huang
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506 USA
| | - Yutong Gu
- Department of Electrical Engineering, University of Southern California, Los Angeles, CA, 90089 USA
| | - Jing Chen
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506 USA
| | - Ahmed A Bahrani
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506 USA
| | - Elie G Abu Jawdeh
- Department of Pediatrics, College of Medicine, University of Kentucky, Lexington, KY 40536 USA
| | - Henrietta S Bada
- Department of Pediatrics, College of Medicine, University of Kentucky, Lexington, KY 40536 USA
| | - Kathryn Saatman
- Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536 USA
| | - Guoqiang Yu
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506 USA
| | - Lei Chen
- Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536 USA
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249
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Abstract
Fluorescent probes that indicate biologically important quantities are widely used for many different types of biological experiments across life sciences. During recent years, limitations of small molecule-based indicators have been overcome by the development of genetically encoded indicators. Here we focus on fluorescent calcium and voltage indicators and point to their applications mainly in neurosciences.
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250
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Conner JM, Bain GL, Dulin JN. Intraspinal and Intracortical Delivery of AAV Vectors for Intersectional Circuit Tracing in Non-transgenic Species. Methods Mol Biol 2019; 1950:165-176. [PMID: 30783973 DOI: 10.1007/978-1-4939-9139-6_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The mapping of long-range axonal projections is a rapidly growing endeavor in the field of neuroscience. Recent advances in the development of adeno-associated viral vectors that can achieve efficient retrograde transport now enable the characterization and manipulation of specific neuronal subpopulations using Cre-dependent, intersectional approaches. Importantly, these approaches can be applied to non-transgenic animals, making it possible to carry out detailed anatomical studies across a variety of species including nonhuman primates. In this chapter, we demonstrate the utility of such intersectional strategies by describing methods for targeting viral constructs to distinct subsets of corticospinal motor neurons based on their projections to specific spinal cord segments.
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Affiliation(s)
- James M Conner
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Greg L Bain
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Jennifer N Dulin
- Department of Biology, Texas A&M University, College Station, TX, USA.
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