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Johnsen KA, Cruzado NA, Menard ZC, Willats AA, Charles AS, Markowitz JE, Rozell CJ. Bridging model and experiment in systems neuroscience with Cleo: the Closed-Loop, Electrophysiology, and Optophysiology simulation testbed. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.01.27.525963. [PMID: 39026717 PMCID: PMC11257437 DOI: 10.1101/2023.01.27.525963] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Systems neuroscience has experienced an explosion of new tools for reading and writing neural activity, enabling exciting new experiments such as all-optical or closed-loop control that effect powerful causal interventions. At the same time, improved computational models are capable of reproducing behavior and neural activity with increasing fidelity. Unfortunately, these advances have drastically increased the complexity of integrating different lines of research, resulting in the missed opportunities and untapped potential of suboptimal experiments. Experiment simulation can help bridge this gap, allowing model and experiment to better inform each other by providing a low-cost testbed for experiment design, model validation, and methods engineering. Specifically, this can be achieved by incorporating the simulation of the experimental interface into our models, but no existing tool integrates optogenetics, two-photon calcium imaging, electrode recording, and flexible closed-loop processing with neural population simulations. To address this need, we have developed Cleo: the Closed-Loop, Electrophysiology, and Optophysiology experiment simulation testbed. Cleo is a Python package enabling injection of recording and stimulation devices as well as closed-loop control with realistic latency into a Brian spiking neural network model. It is the only publicly available tool currently supporting two-photon and multi-opsin/wavelength optogenetics. To facilitate adoption and extension by the community, Cleo is open-source, modular, tested, and documented, and can export results to various data formats. Here we describe the design and features of Cleo, validate output of individual components and integrated experiments, and demonstrate its utility for advancing optogenetic techniques in prospective experiments using previously published systems neuroscience models.
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Affiliation(s)
- Kyle A. Johnsen
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | | | - Zachary C. Menard
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Adam A. Willats
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Adam S. Charles
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - Jeffrey E. Markowitz
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
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2
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Leong LM, Storace DA. Imaging different cell populations in the mouse olfactory bulb using the genetically encoded voltage indicator ArcLight. NEUROPHOTONICS 2024; 11:033402. [PMID: 38288247 PMCID: PMC10823906 DOI: 10.1117/1.nph.11.3.033402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/30/2023] [Accepted: 12/14/2023] [Indexed: 01/31/2024]
Abstract
Genetically encoded voltage indicators (GEVIs) are protein-based optical sensors that allow for measurements from genetically defined populations of neurons. Although in vivo imaging in the mammalian brain with early generation GEVIs was difficult due to poor membrane expression and low signal-to-noise ratio, newer and more sensitive GEVIs have begun to make them useful for answering fundamental questions in neuroscience. We discuss principles of imaging using GEVIs and genetically encoded calcium indicators, both useful tools for in vivo imaging of neuronal activity, and review some of the recent mechanistic advances that have led to GEVI improvements. We provide an overview of the mouse olfactory bulb (OB) and discuss recent studies using the GEVI ArcLight to study different cell types within the bulb using both widefield and two-photon microscopy. Specific emphasis is placed on using GEVIs to begin to study the principles of concentration coding in the OB, how to interpret the optical signals from population measurements in the in vivo brain, and future developments that will push the field forward.
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Affiliation(s)
- Lee Min Leong
- Florida State University, Department of Biological Science, Tallahassee, Florida, United States
| | - Douglas A. Storace
- Florida State University, Department of Biological Science, Tallahassee, Florida, United States
- Florida State University, Program in Neuroscience, Tallahassee, Florida, United States
- Florida State University, Institute of Molecular Biophysics, Tallahassee, Florida, United States
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3
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Márquez-Nogueras KM, Bovo E, Neczypor JE, Cao Q, Zima AV, Kuo IY. Utilization of the genetically encoded calcium indicator Salsa6F in cardiac applications. Cell Calcium 2024; 119:102873. [PMID: 38537433 PMCID: PMC11018326 DOI: 10.1016/j.ceca.2024.102873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/23/2024] [Accepted: 03/13/2024] [Indexed: 04/05/2024]
Abstract
Calcium signaling is a critical process required for cellular mechanisms such as cardiomyocyte contraction. The inability of the cell to properly activate or regulate calcium signaling can lead to contractile dysfunction. In isolated cardiomyocytes, calcium signaling has been primarily studied using calcium fluorescent dyes, however these dyes have limited applicability to whole organs. Here, we crossed the Salsa6f mouse which expresses a genetically encoded ratiometric cytosolic calcium indicator with a cardiomyocyte specific inducible cre to temporally-induce expression and studied cytosolic calcium transients in isolated cardiomyocytes and modified Langendorff heart preparations. Isolated cardiomyocytes expressing Salsa6f or Fluo-4AM loaded were compared. We also crossed the Salsa6f mouse with a floxed Polycystin 2 (PC2) mouse to test the feasibility of using the Salsa6f mouse to measure calcium transients in PC2 heterozygous or homozygous knock out mice. Although there are caveats in the applicability of the Salsa6f mouse, there are clear advantages to using the Salsa6f mouse to measure whole heart calcium signals.
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Affiliation(s)
- Karla M Márquez-Nogueras
- Department of Cell and Molecular Physiology, and Cardiovascular Research Institute, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA
| | - Elisa Bovo
- Department of Cell and Molecular Physiology, and Cardiovascular Research Institute, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA
| | - Jacy E Neczypor
- Department of Cell and Molecular Physiology, and Cardiovascular Research Institute, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA
| | - Quan Cao
- Department of Cell and Molecular Physiology, and Cardiovascular Research Institute, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA
| | - Aleksey V Zima
- Department of Cell and Molecular Physiology, and Cardiovascular Research Institute, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA
| | - Ivana Y Kuo
- Department of Cell and Molecular Physiology, and Cardiovascular Research Institute, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA.
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4
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Sanchez C, Ramirez A, Hodgson L. Unravelling molecular dynamics in living cells: Fluorescent protein biosensors for cell biology. J Microsc 2024. [PMID: 38357769 PMCID: PMC11324865 DOI: 10.1111/jmi.13270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/11/2024] [Accepted: 01/22/2024] [Indexed: 02/16/2024]
Abstract
Genetically encoded, fluorescent protein (FP)-based Förster resonance energy transfer (FRET) biosensors are microscopy imaging tools tailored for the precise monitoring and detection of molecular dynamics within subcellular microenvironments. They are characterised by their ability to provide an outstanding combination of spatial and temporal resolutions in live-cell microscopy. In this review, we begin by tracing back on the historical development of genetically encoded FP labelling for detection in live cells, which lead us to the development of early biosensors and finally to the engineering of single-chain FRET-based biosensors that have become the state-of-the-art today. Ultimately, this review delves into the fundamental principles of FRET and the design strategies underpinning FRET-based biosensors, discusses their diverse applications and addresses the distinct challenges associated with their implementation. We place particular emphasis on single-chain FRET biosensors for the Rho family of guanosine triphosphate hydrolases (GTPases), pointing to their historical role in driving our understanding of the molecular dynamics of this important class of signalling proteins and revealing the intricate relationships and regulatory mechanisms that comprise Rho GTPase biology in living cells.
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Affiliation(s)
- Colline Sanchez
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Andrea Ramirez
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Louis Hodgson
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
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5
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Chen J, Gish CM, Fransen JW, Salazar-Gatzimas E, Clark DA, Borghuis BG. Direct comparison reveals algorithmic similarities in fly and mouse visual motion detection. iScience 2023; 26:107928. [PMID: 37810236 PMCID: PMC10550730 DOI: 10.1016/j.isci.2023.107928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/07/2023] [Accepted: 09/12/2023] [Indexed: 10/10/2023] Open
Abstract
Evolution has equipped vertebrates and invertebrates with neural circuits that selectively encode visual motion. While similarities in the computations performed by these circuits in mouse and fruit fly have been noted, direct experimental comparisons have been lacking. Because molecular mechanisms and neuronal morphology in the two species are distinct, we directly compared motion encoding in these two species at the algorithmic level, using matched stimuli and focusing on a pair of analogous neurons, the mouse ON starburst amacrine cell (ON SAC) and Drosophila T4 neurons. We find that the cells share similar spatiotemporal receptive field structures, sensitivity to spatiotemporal correlations, and tuning to sinusoidal drifting gratings, but differ in their responses to apparent motion stimuli. Both neuron types showed a response to summed sinusoids that deviates from models for motion processing in these cells, underscoring the similarities in their processing and identifying response features that remain to be explained.
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Affiliation(s)
- Juyue Chen
- Interdepartmental Neurosciences Program, Yale University, New Haven, CT 06511, USA
| | - Caitlin M Gish
- Department of Physics, Yale University, New Haven, CT 06511, USA
| | - James W Fransen
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40202, USA
| | | | - Damon A Clark
- Interdepartmental Neurosciences Program, Yale University, New Haven, CT 06511, USA
- Department of Physics, Yale University, New Haven, CT 06511, USA
- Department of Molecular, Cellular, Developmental Biology, Yale University, New Haven, CT 06511, USA
- Department of Neuroscience, Yale University, New Haven, CT 06511, USA
| | - Bart G Borghuis
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40202, USA
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Eisner D, Neher E, Taschenberger H, Smith G. Physiology of intracellular calcium buffering. Physiol Rev 2023; 103:2767-2845. [PMID: 37326298 DOI: 10.1152/physrev.00042.2022] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 05/08/2023] [Accepted: 06/11/2023] [Indexed: 06/17/2023] Open
Abstract
Calcium signaling underlies much of physiology. Almost all the Ca2+ in the cytoplasm is bound to buffers, with typically only ∼1% being freely ionized at resting levels in most cells. Physiological Ca2+ buffers include small molecules and proteins, and experimentally Ca2+ indicators will also buffer calcium. The chemistry of interactions between Ca2+ and buffers determines the extent and speed of Ca2+ binding. The physiological effects of Ca2+ buffers are determined by the kinetics with which they bind Ca2+ and their mobility within the cell. The degree of buffering depends on factors such as the affinity for Ca2+, the Ca2+ concentration, and whether Ca2+ ions bind cooperatively. Buffering affects both the amplitude and time course of cytoplasmic Ca2+ signals as well as changes of Ca2+ concentration in organelles. It can also facilitate Ca2+ diffusion inside the cell. Ca2+ buffering affects synaptic transmission, muscle contraction, Ca2+ transport across epithelia, and the killing of bacteria. Saturation of buffers leads to synaptic facilitation and tetanic contraction in skeletal muscle and may play a role in inotropy in the heart. This review focuses on the link between buffer chemistry and function and how Ca2+ buffering affects normal physiology and the consequences of changes in disease. As well as summarizing what is known, we point out the many areas where further work is required.
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Affiliation(s)
- David Eisner
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Erwin Neher
- Membrane Biophysics Laboratory, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Holger Taschenberger
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Godfrey Smith
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Patel N, Ouellet V, Paquet-Mercier F, Chetoui N, Bélanger E, Paquet ME, Godin AG, Marquet P. A robust and reliable methodology to perform GECI-based multi-time point neuronal calcium imaging within mixed cultures of human iPSC-derived cortical neurons. Front Neurosci 2023; 17:1247397. [PMID: 37817802 PMCID: PMC10560759 DOI: 10.3389/fnins.2023.1247397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 08/16/2023] [Indexed: 10/12/2023] Open
Abstract
Introduction Human induced pluripotent stem cells (iPSCs), with their ability to generate human neural cells (astrocytes and neurons) from patients, hold great promise for understanding the pathophysiology of major neuropsychiatric diseases such as schizophrenia and bipolar disorders, which includes alterations in cerebral development. Indeed, the in vitro neurodifferentiation of iPSCs, while recapitulating certain major stages of neurodevelopment in vivo, makes it possible to obtain networks of living human neurons. The culture model presented is particularly attractive within this framework since it involves iPSC-derived neural cells, which more specifically differentiate into cortical neurons of diverse types (in particular glutamatergic and GABAergic) and astrocytes. However, these in vitro neuronal networks, which may be heterogeneous in their degree of differentiation, remain challenging to bring to an appropriate level of maturation. It is therefore necessary to develop tools capable of analyzing a large number of cells to assess this maturation process. Calcium (Ca2+) imaging, which has been extensively developed, undoubtedly offers an incredibly good approach, particularly in its versions using genetically encoded calcium indicators. However, in the context of these iPSC-derived neural cell cultures, there is a lack of studies that propose Ca2+ imaging methods that can finely characterize the evolution of neuronal maturation during the neurodifferentiation process. Methods In this study, we propose a robust and reliable method for specifically measuring neuronal activity at two different time points of the neurodifferentiation process in such human neural cultures. To this end, we have developed a specific Ca2+ signal analysis procedure and tested a series of different AAV serotypes to obtain expression levels of GCaMP6f under the control of the neuron-specific human synapsin1 (hSyn) promoter. Results The retro serotype has been found to be the most efficient in driving the expression of the GCaMP6f and is compatible with multi-time point neuronal Ca2+ imaging in our human iPSC-derived neural cultures. An AAV2/retro carrying GCaMP6f under the hSyn promoter (AAV2/retro-hSyn-GCaMP6f) is an efficient vector that we have identified. To establish the method, calcium measurements were carried out at two time points in the neurodifferentiation process with both hSyn and CAG promoters, the latter being known to provide high transient gene expression across various cell types. Discussion Our results stress that this methodology involving AAV2/retro-hSyn-GCaMP6f is suitable for specifically measuring neuronal calcium activities over multiple time points and is compatible with the neurodifferentiation process in our mixed human neural cultures.
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Affiliation(s)
- Niraj Patel
- Department of Psychiatry and Neuroscience, Laval University, Quebec, QC, Canada
- CERVO Brain Research Centre, Laval University, Quebec, QC, Canada
| | - Vincent Ouellet
- Department of Psychiatry and Neuroscience, Laval University, Quebec, QC, Canada
- CERVO Brain Research Centre, Laval University, Quebec, QC, Canada
| | | | - Nizar Chetoui
- CERVO Brain Research Centre, Laval University, Quebec, QC, Canada
| | - Erik Bélanger
- CERVO Brain Research Centre, Laval University, Quebec, QC, Canada
| | - Marie-Eve Paquet
- CERVO Brain Research Centre, Laval University, Quebec, QC, Canada
- Department of Biochemistry, Microbiology and Bioinformatics, Laval University, Quebec, QC, Canada
| | - Antoine G. Godin
- Department of Psychiatry and Neuroscience, Laval University, Quebec, QC, Canada
- CERVO Brain Research Centre, Laval University, Quebec, QC, Canada
- Centre for Optics, Photonics and Lasers (COPL), Laval University, Quebec, QC, Canada
| | - Pierre Marquet
- Department of Psychiatry and Neuroscience, Laval University, Quebec, QC, Canada
- CERVO Brain Research Centre, Laval University, Quebec, QC, Canada
- Centre for Optics, Photonics and Lasers (COPL), Laval University, Quebec, QC, Canada
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8
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Cunha MR, Catta-Preta CMC, Takarada JE, Moreira GA, Massirer KB, Couñago RM. A novel BRET-based assay to investigate binding and residence times of unmodified ligands to the human lysosomal ion channel TRPML1 in intact cells. J Biol Chem 2023:104807. [PMID: 37172730 DOI: 10.1016/j.jbc.2023.104807] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/17/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Here we report a Bioluminescence Resonance Energy Transfer (BRET) assay as a novel way to investigate the binding of unlabeled ligands to the human Transient Receptor Potential Mucolipin 1 (hTRPML1), a lysosomal ion channel involved in several genetic diseases and cancer progression. This novel BRET assay can be used to determine equilibrium and kinetic binding parameters of unlabeled compounds to hTRPML1 using intact human-derived cells, thus complementing the information obtained using functional assays based on ion channel activation. We expect this new BRET assay to expedite the identification and optimization of cell-permeable ligands that interact with hTRPML1 within the physiologically-relevant environment of lysosomes.
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Affiliation(s)
- Micael R Cunha
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil.
| | - Carolina M C Catta-Preta
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil; Current address: Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jéssica E Takarada
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil
| | - Gabriela A Moreira
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil
| | - Katlin B Massirer
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil.
| | - Rafael M Couñago
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil; Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States.
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9
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Abstract
The genetically encoded fluorescent sensors convert chemical and physical signals into light. They are powerful tools for the visualisation of physiological processes in living cells and freely moving animals. The fluorescent protein is the reporter module of a genetically encoded biosensor. In this study, we first review the history of the fluorescent protein in full emission spectra on a structural basis. Then, we discuss the design of the genetically encoded biosensor. Finally, we briefly review several major types of genetically encoded biosensors that are currently widely used based on their design and molecular targets, which may be useful for the future design of fluorescent biosensors.
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Affiliation(s)
- Minji Wang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, No. 3663 Zhong Shan Road North, Shanghai, 200062, China
| | - Yifan Da
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, No. 3663 Zhong Shan Road North, Shanghai, 200062, China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, No. 3663 Zhong Shan Road North, Shanghai, 200062, China
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10
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Functional Two-Dimensional Materials for Bioelectronic Neural Interfacing. J Funct Biomater 2023; 14:jfb14010035. [PMID: 36662082 PMCID: PMC9863167 DOI: 10.3390/jfb14010035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/26/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
Realizing the neurological information processing by analyzing the complex data transferring behavior of populations and individual neurons is one of the fast-growing fields of neuroscience and bioelectronic technologies. This field is anticipated to cover a wide range of advanced applications, including neural dynamic monitoring, understanding the neurological disorders, human brain-machine communications and even ambitious mind-controlled prosthetic implant systems. To fulfill the requirements of high spatial and temporal resolution recording of neural activities, electrical, optical and biosensing technologies are combined to develop multifunctional bioelectronic and neuro-signal probes. Advanced two-dimensional (2D) layered materials such as graphene, graphene oxide, transition metal dichalcogenides and MXenes with their atomic-layer thickness and multifunctional capabilities show bio-stimulation and multiple sensing properties. These characteristics are beneficial factors for development of ultrathin-film electrodes for flexible neural interfacing with minimum invasive chronic interfaces to the brain cells and cortex. The combination of incredible properties of 2D nanostructure places them in a unique position, as the main materials of choice, for multifunctional reception of neural activities. The current review highlights the recent achievements in 2D-based bioelectronic systems for monitoring of biophysiological indicators and biosignals at neural interfaces.
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11
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Nietz AK, Popa LS, Streng ML, Carter RE, Kodandaramaiah SB, Ebner TJ. Wide-Field Calcium Imaging of Neuronal Network Dynamics In Vivo. BIOLOGY 2022; 11:1601. [PMID: 36358302 PMCID: PMC9687960 DOI: 10.3390/biology11111601] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
A central tenet of neuroscience is that sensory, motor, and cognitive behaviors are generated by the communications and interactions among neurons, distributed within and across anatomically and functionally distinct brain regions. Therefore, to decipher how the brain plans, learns, and executes behaviors requires characterizing neuronal activity at multiple spatial and temporal scales. This includes simultaneously recording neuronal dynamics at the mesoscale level to understand the interactions among brain regions during different behavioral and brain states. Wide-field Ca2+ imaging, which uses single photon excitation and improved genetically encoded Ca2+ indicators, allows for simultaneous recordings of large brain areas and is proving to be a powerful tool to study neuronal activity at the mesoscopic scale in behaving animals. This review details the techniques used for wide-field Ca2+ imaging and the various approaches employed for the analyses of the rich neuronal-behavioral data sets obtained. Also discussed is how wide-field Ca2+ imaging is providing novel insights into both normal and altered neural processing in disease. Finally, we examine the limitations of the approach and new developments in wide-field Ca2+ imaging that are bringing new capabilities to this important technique for investigating large-scale neuronal dynamics.
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Affiliation(s)
- Angela K. Nietz
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Laurentiu S. Popa
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Martha L. Streng
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Russell E. Carter
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Timothy J. Ebner
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
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12
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Benisty H, Song A, Mishne G, Charles AS. Review of data processing of functional optical microscopy for neuroscience. NEUROPHOTONICS 2022; 9:041402. [PMID: 35937186 PMCID: PMC9351186 DOI: 10.1117/1.nph.9.4.041402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 07/15/2022] [Indexed: 05/04/2023]
Abstract
Functional optical imaging in neuroscience is rapidly growing with the development of optical systems and fluorescence indicators. To realize the potential of these massive spatiotemporal datasets for relating neuronal activity to behavior and stimuli and uncovering local circuits in the brain, accurate automated processing is increasingly essential. We cover recent computational developments in the full data processing pipeline of functional optical microscopy for neuroscience data and discuss ongoing and emerging challenges.
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Affiliation(s)
- Hadas Benisty
- Yale Neuroscience, New Haven, Connecticut, United States
| | - Alexander Song
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Gal Mishne
- UC San Diego, Halıcığlu Data Science Institute, Department of Electrical and Computer Engineering and the Neurosciences Graduate Program, La Jolla, California, United States
| | - Adam S. Charles
- Johns Hopkins University, Kavli Neuroscience Discovery Institute, Center for Imaging Science, Department of Biomedical Engineering, Department of Neuroscience, and Mathematical Institute for Data Science, Baltimore, Maryland, United States
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13
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Malci A, Lin X, Sandoval R, Gundelfinger ED, Naumann M, Seidenbecher CI, Herrera-Molina R. Ca 2+ signaling in postsynaptic neurons: Neuroplastin-65 regulates the interplay between plasma membrane Ca 2+ ATPases and ionotropic glutamate receptors. Cell Calcium 2022; 106:102623. [PMID: 35853264 DOI: 10.1016/j.ceca.2022.102623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 06/28/2022] [Accepted: 07/05/2022] [Indexed: 11/17/2022]
Abstract
Upon postsynaptic glutamate receptor activation, the cytosolic Ca2+ concentration rises and initiates signaling and plasticity in spines. The plasma membrane Ca2+ ATPase (PMCA) is a major player to limit the duration of cytosolic Ca2+ signals. It forms complexes with the glycoprotein neuroplastin (Np) isoforms Np55 and Np65 and functionally interplays with N-methyl-D-aspartate (NMDA)-type ionotropic glutamate receptors (iGluNRs). Moreover, binding of the Np65-specific extracellular domain to Ca2+-permeable GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type ionotropic glutamate receptors (iGluA1Rs) was found to be required for long-term potentiation (LTP). However, the link between PMCA and iGluRs function to regulate cytosolic Ca2+ signals remained unclear. Here, we report that Np65 coordinates PMCA and iGluRs' functions to modulate the duration and amplitude of cytosolic Ca2+ transients in dendrites and spines of hippocampal neurons. Using live-cell Ca2+ imaging, acute pharmacological treatments, and GCaMP5G-expressing hippocampal neurons, we discovered that endogenous or Np65-promoted PMCA activity contributes to the restoration of basal Ca2+ levels and that this effect is dependent on iGluR activation. Super-resolution STED and confocal microscopy revealed that electrical stimulation increases the abundance of synaptic neuroplastin-PMCA complexes depending on iGluR activation and that low-rate overexpression of Np65 doubled PMCA levels and decreased cell surface levels of GluN2A and GluA1 in dendrites and Shank2-positive glutamatergic synapses. In neuroplastin-deficient hippocampi, we observed reduced PMCA and unchanged GluN2B levels, while GluN2A and GluA1 levels were imbalanced. Our electrophysiological data from hippocampal slices argues for an essential interplay of PMCA with GluN2A- but not with GluN2B-containing receptors upon induction of synaptic plasticity. Accordingly, we conclude that Np65 may interconnect PMCA with core players of glutamatergic neurotransmission to fine-tune the Ca2+ signal regulation in basal synaptic function and plasticity.
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Affiliation(s)
- Ayse Malci
- Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Xiao Lin
- Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Rodrigo Sandoval
- Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
| | - Eckart D Gundelfinger
- Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany; Institute of Pharmacology and Toxicology, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Constanze I Seidenbecher
- Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Rodrigo Herrera-Molina
- Center for Behavioral Brain Sciences, Magdeburg, Germany; Centro Integrativo de Biología y Química Aplicada, Universidad Bernardo O'Higgins, Santiago, Chile; Combinatorial Combinatorial NeuroImaging (CNI), Leibniz Institute for Neurobiology, Magdeburg, Germany.
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14
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Kempmann A, Gensch T, Offenhäusser A, Tihaa I, Maybeck V, Balfanz S, Baumann A. The Functional Characterization of GCaMP3.0 Variants Specifically Targeted to Subcellular Domains. Int J Mol Sci 2022; 23:ijms23126593. [PMID: 35743038 PMCID: PMC9223625 DOI: 10.3390/ijms23126593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/31/2022] [Accepted: 06/06/2022] [Indexed: 11/16/2022] Open
Abstract
Calcium (Ca2+) ions play a pivotal role in physiology and cellular signaling. The intracellular Ca2+ concentration ([Ca2+]i) is about three orders of magnitude lower than the extracellular concentration, resulting in a steep transmembrane concentration gradient. Thus, the spatial and the temporal dynamics of [Ca2+]i are ideally suited to modulate Ca2+-mediated cellular responses to external signals. A variety of highly sophisticated methods have been developed to gain insight into cellular Ca2+ dynamics. In addition to electrophysiological measurements and the application of synthetic dyes that change their fluorescent properties upon interaction with Ca2+, the introduction and the ongoing development of genetically encoded Ca2+ indicators (GECI) opened a new era to study Ca2+-driven processes in living cells and organisms. Here, we have focused on one well-established GECI, i.e., GCaMP3.0. We have systematically modified the protein with sequence motifs, allowing localization of the sensor in the nucleus, in the mitochondrial matrix, at the mitochondrial outer membrane, and at the plasma membrane. The individual variants and a cytosolic version of GCaMP3.0 were overexpressed and purified from E. coli cells to study their biophysical properties in solution. All versions were examined to monitor Ca2+ signaling in stably transfected cell lines and in primary cortical neurons transduced with recombinant Adeno-associated viruses (rAAV). In this comparative study, we provide evidence for a robust approach to reliably trace Ca2+ signals at the (sub)-cellular level with pronounced temporal resolution.
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Affiliation(s)
- Annika Kempmann
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
| | - Thomas Gensch
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
| | - Andreas Offenhäusser
- Institute of Biological Information Processing, IBI-3, Research Center Jülich, 52428 Jülich, Germany; (A.O.); (I.T.); (V.M.)
| | - Irina Tihaa
- Institute of Biological Information Processing, IBI-3, Research Center Jülich, 52428 Jülich, Germany; (A.O.); (I.T.); (V.M.)
| | - Vanessa Maybeck
- Institute of Biological Information Processing, IBI-3, Research Center Jülich, 52428 Jülich, Germany; (A.O.); (I.T.); (V.M.)
| | - Sabine Balfanz
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
| | - Arnd Baumann
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
- Correspondence: ; Tel.: +49-2461-614014
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15
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Charles AS, Cermak N, Affan RO, Scott BB, Schiller J, Mishne G. GraFT: Graph Filtered Temporal Dictionary Learning for Functional Neural Imaging. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2022; 31:3509-3524. [PMID: 35533160 PMCID: PMC9278524 DOI: 10.1109/tip.2022.3171414] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Optical imaging of calcium signals in the brain has enabled researchers to observe the activity of hundreds-to-thousands of individual neurons simultaneously. Current methods predominantly use morphological information, typically focusing on expected shapes of cell bodies, to better identify neurons in the field-of-view. The explicit shape constraints limit the applicability of automated cell identification to other important imaging scales with more complex morphologies, e.g., dendritic or widefield imaging. Specifically, fluorescing components may be broken up, incompletely found, or merged in ways that do not accurately describe the underlying neural activity. Here we present Graph Filtered Temporal Dictionary (GraFT), a new approach that frames the problem of isolating independent fluorescing components as a dictionary learning problem. Specifically, we focus on the time-traces-the main quantity used in scientific discovery-and learn a time trace dictionary with the spatial maps acting as the presence coefficients encoding which pixels the time-traces are active in. Furthermore, we present a novel graph filtering model which redefines connectivity between pixels in terms of their shared temporal activity, rather than spatial proximity. This model greatly eases the ability of our method to handle data with complex non-local spatial structure. We demonstrate important properties of our method, such as robustness to morphology, simultaneously detecting different neuronal types, and implicitly inferring number of neurons, on both synthetic data and real data examples. Specifically, we demonstrate applications of our method to calcium imaging both at the dendritic, somatic, and widefield scales.
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16
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Gauthier JL, Koay SA, Nieh EH, Tank DW, Pillow JW, Charles AS. Detecting and correcting false transients in calcium imaging. Nat Methods 2022; 19:470-478. [PMID: 35347320 PMCID: PMC10715860 DOI: 10.1038/s41592-022-01422-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 02/10/2022] [Indexed: 11/08/2022]
Abstract
Population recordings of calcium activity are a major source of insight into neural function. Large datasets require automated processing, but this can introduce errors that are difficult to detect. Here we show that popular time course-estimation algorithms often contain substantial misattribution errors affecting 10-20% of transients. Misattribution, in which fluorescence is ascribed to the wrong cell, arises when overlapping cells and processes are imperfectly defined or not identified. To diagnose misattribution, we develop metrics and visualization tools for evaluating large datasets. To correct time courses, we introduce a robust estimator that explicitly accounts for contaminating signals. In one hippocampal dataset, removing contamination reduced the number of place cells by 15%, and 19% of place fields shifted by over 10 cm. Our methods are compatible with other cell-finding techniques, empowering users to diagnose and correct a potentially widespread problem that could alter scientific conclusions.
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Affiliation(s)
| | - Sue Ann Koay
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Edward H Nieh
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - David W Tank
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA.
- Bezos Center for Neural Circuit Dynamics, Princeton University, Princeton, NJ, USA.
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
| | - Jonathan W Pillow
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
- Department of Psychology, Princeton University, Princeton, NJ, USA
| | - Adam S Charles
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA.
- Center for Imaging Science, Johns Hopkins University, Baltimore, MD, USA.
- Mathematical Institute for Data Science, Johns Hopkins University, Baltimore, MD, USA.
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17
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Margiotta JF, Smith-Edwards KM, Nestor-Kalinoski A, Davis BM, Albers KM, Howard MJ. Synaptic Components, Function and Modulation Characterized by GCaMP6f Ca 2+ Imaging in Mouse Cholinergic Myenteric Ganglion Neurons. Front Physiol 2021; 12:652714. [PMID: 34408655 PMCID: PMC8365335 DOI: 10.3389/fphys.2021.652714] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 06/28/2021] [Indexed: 12/12/2022] Open
Abstract
The peristaltic contraction and relaxation of intestinal circular and longitudinal smooth muscles is controlled by synaptic circuit elements that impinge upon phenotypically diverse neurons in the myenteric plexus. While electrophysiological studies provide useful information concerning the properties of such synaptic circuits, they typically involve tissue disruption and do not correlate circuit activity with biochemically defined neuronal phenotypes. To overcome these limitations, mice were engineered to express the sensitive, fast Ca2+ indicator GCaMP6f selectively in neurons that express the acetylcholine (ACh) biosynthetic enzyme choline acetyltransfarse (ChAT) thereby allowing rapid activity-driven changes in Ca2+ fluorescence to be observed without disrupting intrinsic connections, solely in cholinergic myenteric ganglion (MG) neurons. Experiments with selective receptor agonists and antagonists reveal that most mouse colonic cholinergic (i.e., GCaMP6f+/ChAT+) MG neurons express nicotinic ACh receptors (nAChRs), particularly the ganglionic subtype containing α3 and β4 subunits, and most express ionotropic serotonin receptors (5-HT3Rs). Cholinergic MG neurons also display small, spontaneous Ca2+ transients occurring at ≈ 0.2 Hz. Experiments with inhibitors of Na+ channel dependent impulses, presynaptic Ca2+ channels and postsynaptic receptor function reveal that the Ca2+ transients arise from impulse-driven presynaptic activity and subsequent activation of postsynaptic nAChRs or 5-HT3Rs. Electrical stimulation of axonal connectives to MG evoked Ca2+ responses in the neurons that similarly depended on nAChRs or/and 5-HT3Rs. Responses to single connective shocks had peak amplitudes and rise and decay times that were indistinguishable from the spontaneous Ca2+ transients and the largest fraction had brief synaptic delays consistent with activation by monosynaptic inputs. These results indicate that the spontaneous Ca2+ transients and stimulus evoked Ca2+ responses in MG neurons originate in circuits involving fast chemical synaptic transmission mediated by nAChRs or/and 5-HT3Rs. Experiments with an α7-nAChR agonist and antagonist, and with pituitary adenylate cyclase activating polypeptide (PACAP) reveal that the same synaptic circuits display extensive capacity for presynaptic modulation. Our use of non-invasive GCaMP6f/ChAT Ca2+ imaging in colon segments with intrinsic connections preserved, reveals an abundance of direct and modulatory synaptic influences on cholinergic MG neurons.
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Affiliation(s)
- Joseph F Margiotta
- Department of Neurosciences, College of Medicine and Life Sciences, University of Toledo, Toledo, OH, United States
| | - Kristen M Smith-Edwards
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Andrea Nestor-Kalinoski
- Department of Surgery, College of Medicine and Life Sciences, University of Toledo, Toledo, OH, United States
| | - Brian M Davis
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Kathryn M Albers
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Marthe J Howard
- Department of Neurosciences, College of Medicine and Life Sciences, University of Toledo, Toledo, OH, United States
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18
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Wei L, Xue Z, Lan B, Yuan S, Li Y, Guo C, Zhang R, Ding R, Shen H. Arctigenin Exerts Neuroprotective Effect by Ameliorating Cortical Activities in Experimental Autoimmune Encephalomyelitis In Vivo. Front Immunol 2021; 12:691590. [PMID: 34349758 PMCID: PMC8327179 DOI: 10.3389/fimmu.2021.691590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/01/2021] [Indexed: 11/19/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic disease in the central nervous system (CNS), characterized by inflammatory cells that invade into the brain and the spinal cord. Among a bulk of different MS models, the most widely used and best understood rodent model is experimental autoimmune encephalomyelitis (EAE). Arctigenin, a botanical extract from Arctium lappa, is reported to exhibit pharmacological properties, including anti-inflammation and neuroprotection. However, the effects of arctigenin on neural activity attacked by inflammation in MS are still unclear. Here, we use two-photon calcium imaging to observe the activity of somatosensory cortex neurons in awake EAE mice in vivo and found added hyperactive cells, calcium influx, network connectivity, and synchronization, mainly at preclinical stage of EAE model. Besides, more silent cells and decreased calcium influx and reduced network synchronization accompanied by a compensatory rise in functional connectivity are found at the remission stage. Arctigenin treatment not only restricts inordinate individually neural spiking, calcium influx, and network activity at preclinical stage but also restores neuronal activity and communication at remission stage. In addition, we confirm that the frequency of AMPA receptor-mediated spontaneous excitatory postsynaptic current (sEPSC) is also increased at preclinical stage and can be blunted by arctigenin. These findings suggest that excitotoxicity characterized by calcium influx is involved in EAE at preclinical stage. What is more, arctigenin exerts neuroprotective effect by limiting hyperactivity at preclinical stage and ameliorates EAE symptoms, indicating that arctigenin could be a potential therapeutic drug for neuroprotection in MS-related neuropsychological disorders.
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Affiliation(s)
- Liangpeng Wei
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China
| | - Zhenyi Xue
- Department of Immunology, Key Laboratory of Immune Microenvironment and Diseases of Educational Ministry of China, Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China
| | - Baihui Lan
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China
| | - Shiyang Yuan
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China
| | - Yuanyuan Li
- Innovation Institute of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Cunle Guo
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China
| | - Rongxin Zhang
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
| | - Ran Ding
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Chinese Institute for Brain Research, Beijing, China
| | - Hui Shen
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China
- Research Institute of Neurology, General Hospital, Tianjin Medical University, Tianjin, China
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19
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Takano T, Wahl AM, Huang KT, Narita T, Rugis J, Sneyd J, Yule DI. Highly localized intracellular Ca 2+ signals promote optimal salivary gland fluid secretion. eLife 2021; 10:66170. [PMID: 34240705 PMCID: PMC8352588 DOI: 10.7554/elife.66170] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 07/08/2021] [Indexed: 11/23/2022] Open
Abstract
Salivary fluid secretion involves an intricate choreography of membrane transporters to result in the trans-epithelial movement of NaCl and water into the acinus lumen. Current models are largely based on experimental observations in enzymatically isolated cells where the Ca2+ signal invariably propagates globally and thus appears ideally suited to activate spatially separated Cl and K channels, present on the apical and basolateral plasma membrane, respectively. We monitored Ca2+ signals and salivary secretion in live mice expressing GCamp6F, following stimulation of the nerves innervating the submandibular gland. Consistent with in vitro studies, Ca2+ signals were initiated in the apical endoplasmic reticulum. In marked contrast to in vitro data, highly localized trains of Ca2+ transients that failed to fully propagate from the apical region were observed. Following stimuli optimum for secretion, large apical-basal gradients were elicited. A new mathematical model, incorporating these data was constructed to probe how salivary secretion can be optimally stimulated by apical Ca2+ signals.
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Affiliation(s)
- Takahiro Takano
- Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
| | - Amanda M Wahl
- Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
| | - Kai-Ting Huang
- Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
| | - Takanori Narita
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - John Rugis
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - James Sneyd
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
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20
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Song A, Gauthier JL, Pillow JW, Tank DW, Charles AS. Neural anatomy and optical microscopy (NAOMi) simulation for evaluating calcium imaging methods. J Neurosci Methods 2021; 358:109173. [PMID: 33839190 PMCID: PMC8217135 DOI: 10.1016/j.jneumeth.2021.109173] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND The past decade has seen a multitude of new in vivo functional imaging methodologies. However, the lack of ground-truth comparisons or evaluation metrics makes the large-scale, systematic validation vital to the continued development and use of optical microscopy impossible. NEW-METHOD We provide a new framework for evaluating two-photon microscopy methods via in silico Neural Anatomy and Optical Microscopy (NAOMi) simulation. Our computationally efficient model generates large anatomical volumes of mouse cortex, simulates neural activity, and incorporates optical propagation and scanning to create realistic calcium imaging datasets. RESULTS We verify NAOMi simulations against in vivo two-photon recordings from mouse cortex. We leverage this in silico ground truth to directly compare different segmentation algorithms and optical designs. We find modern segmentation algorithms extract strong neural time-courses comparable to estimation using oracle spatial information, but with an increase in the false positive rate. Comparison between optical setups demonstrate improved resilience to motion artifacts in sparsely labeled samples using Bessel beams, increased signal-to-noise ratio and cell-count using low numerical aperture Gaussian beams and nuclear GCaMP, and more uniform spatial sampling with temporal focusing versus multi-plane imaging. COMPARISON WITH EXISTING METHODS NAOMi is a first-of-its kind framework for assessing optical imaging modalities. Existing methods are either anatomical simulations or do not address functional imaging. Thus there is no competing method for simulating realistic functional optical microscopy data. CONCLUSIONS By leveraging the rich accumulated knowledge of neural anatomy and optical physics, we provide a powerful new tool to assess and develop important methods in neural imaging.
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Affiliation(s)
- Alexander Song
- Princeton Neuroscience Institute, Princeton University, Princeton, 08540 NJ, USA; Department of Physics, Princeton University, Princeton, 08540 NJ, USA
| | - Jeff L Gauthier
- Princeton Neuroscience Institute, Princeton University, Princeton, 08540 NJ, USA
| | - Jonathan W Pillow
- Princeton Neuroscience Institute, Princeton University, Princeton, 08540 NJ, USA; Department of Psychology, Princeton University, Princeton, 08540 NJ, USA
| | - David W Tank
- Princeton Neuroscience Institute, Princeton University, Princeton, 08540 NJ, USA; Bezos Center for Neural Circuit Dynamics, Princeton University, Princeton, 08540 NJ, USA; Department of Molecular Biology, Princeton University, Princeton, 08540 NJ, USA
| | - Adam S Charles
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, 21218, MD, USA; Mathematical Institute for Data Science, Johns Hopkins University, Baltimore, 21218, MD, USA; Center for Imaging Science, Johns Hopkins University, Baltimore, 21218, MD, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, 21218, MD, USA
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21
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Rahmati Ishka M, Brown E, Rosenberg A, Romanowsky S, Davis JA, Choi WG, Harper JF. Arabidopsis Ca2+-ATPases 1, 2, and 7 in the endoplasmic reticulum contribute to growth and pollen fitness. PLANT PHYSIOLOGY 2021; 185:1966-1985. [PMID: 33575795 PMCID: PMC8133587 DOI: 10.1093/plphys/kiab021] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 11/23/2020] [Indexed: 05/18/2023]
Abstract
Generating cellular Ca2+ signals requires coordinated transport activities from both Ca2+ influx and efflux pathways. In Arabidopsis (Arabidopsis thaliana), multiple efflux pathways exist, some of which involve Ca2+-pumps belonging to the Autoinhibited Ca2+-ATPase (ACA) family. Here, we show that ACA1, 2, and 7 localize to the endoplasmic reticulum (ER) and are important for plant growth and pollen fertility. While phenotypes for plants harboring single-gene knockouts (KOs) were weak or undetected, a triple KO of aca1/2/7 displayed a 2.6-fold decrease in pollen transmission efficiency, whereas inheritance through female gametes was normal. The triple KO also resulted in smaller rosettes showing a high frequency of lesions. Both vegetative and reproductive phenotypes were rescued by transgenes encoding either ACA1, 2, or 7, suggesting that all three isoforms are biochemically redundant. Lesions were suppressed by expression of a transgene encoding NahG, an enzyme that degrades salicylic acid (SA). Triple KO mutants showed elevated mRNA expression for two SA-inducible marker genes, Pathogenesis-related1 (PR1) and PR2. The aca1/2/7 lesion phenotype was similar but less severe than SA-dependent lesions associated with a double KO of vacuolar pumps aca4 and 11. Imaging of Ca2+ dynamics triggered by blue light or the pathogen elicitor flg22 revealed that aca1/2/7 mutants display Ca2+ transients with increased magnitudes and durations. Together, these results indicate that ER-localized ACAs play important roles in regulating Ca2+ signals, and that the loss of these pumps results in male fertility and vegetative growth deficiencies.
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Affiliation(s)
- Maryam Rahmati Ishka
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Elizabeth Brown
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Alexa Rosenberg
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Shawn Romanowsky
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - James A Davis
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Won-Gyu Choi
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Jeffrey F Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
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22
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Population imaging discrepancies between a genetically-encoded calcium indicator (GECI) versus a genetically-encoded voltage indicator (GEVI). Sci Rep 2021; 11:5295. [PMID: 33674659 PMCID: PMC7935943 DOI: 10.1038/s41598-021-84651-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/11/2021] [Indexed: 11/25/2022] Open
Abstract
Genetically-encoded calcium indicators (GECIs) are essential for studying brain function, while voltage indicators (GEVIs) are slowly permeating neuroscience. Fundamentally, GECI and GEVI measure different things, but both are advertised as reporters of “neuronal activity”. We quantified the similarities and differences between calcium and voltage imaging modalities, in the context of population activity (without single-cell resolution) in brain slices. GECI optical signals showed 8–20 times better SNR than GEVI signals, but GECI signals attenuated more with distance from the stimulation site. We show the exact temporal discrepancy between calcium and voltage imaging modalities, and discuss the misleading aspects of GECI imaging. For example, population voltage signals already repolarized to the baseline (~ disappeared), while the GECI signals were still near maximum. The region-to-region propagation latencies, easily captured by GEVI imaging, are blurred in GECI imaging. Temporal summation of GECI signals is highly exaggerated, causing uniform voltage events produced by neuronal populations to appear with highly variable amplitudes in GECI population traces. Relative signal amplitudes in GECI recordings are thus misleading. In simultaneous recordings from multiple sites, the compound EPSP signals in cortical neuropil (population signals) are less distorted by GEVIs than by GECIs.
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23
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Li ES, Saha MS. Optimizing Calcium Detection Methods in Animal Systems: A Sandbox for Synthetic Biology. Biomolecules 2021; 11:343. [PMID: 33668387 PMCID: PMC7996158 DOI: 10.3390/biom11030343] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 12/16/2022] Open
Abstract
Since the 1970s, the emergence and expansion of novel methods for calcium ion (Ca2+) detection have found diverse applications in vitro and in vivo across a series of model animal systems. Matched with advances in fluorescence imaging techniques, the improvements in the functional range and stability of various calcium indicators have significantly enhanced more accurate study of intracellular Ca2+ dynamics and its effects on cell signaling, growth, differentiation, and regulation. Nonetheless, the current limitations broadly presented by organic calcium dyes, genetically encoded calcium indicators, and calcium-responsive nanoparticles suggest a potential path toward more rapid optimization by taking advantage of a synthetic biology approach. This engineering-oriented discipline applies principles of modularity and standardization to redesign and interrogate endogenous biological systems. This review will elucidate how novel synthetic biology technologies constructed for eukaryotic systems can offer a promising toolkit for interfacing with calcium signaling and overcoming barriers in order to accelerate the process of Ca2+ detection optimization.
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Affiliation(s)
| | - Margaret S. Saha
- Department of Biology, College of William and Mary, Williamsburg, VA 23185, USA;
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24
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Forro C, Caron D, Angotzi GN, Gallo V, Berdondini L, Santoro F, Palazzolo G, Panuccio G. Electrophysiology Read-Out Tools for Brain-on-Chip Biotechnology. MICROMACHINES 2021; 12:124. [PMID: 33498905 PMCID: PMC7912435 DOI: 10.3390/mi12020124] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 02/07/2023]
Abstract
Brain-on-Chip (BoC) biotechnology is emerging as a promising tool for biomedical and pharmaceutical research applied to the neurosciences. At the convergence between lab-on-chip and cell biology, BoC couples in vitro three-dimensional brain-like systems to an engineered microfluidics platform designed to provide an in vivo-like extrinsic microenvironment with the aim of replicating tissue- or organ-level physiological functions. BoC therefore offers the advantage of an in vitro reproduction of brain structures that is more faithful to the native correlate than what is obtained with conventional cell culture techniques. As brain function ultimately results in the generation of electrical signals, electrophysiology techniques are paramount for studying brain activity in health and disease. However, as BoC is still in its infancy, the availability of combined BoC-electrophysiology platforms is still limited. Here, we summarize the available biological substrates for BoC, starting with a historical perspective. We then describe the available tools enabling BoC electrophysiology studies, detailing their fabrication process and technical features, along with their advantages and limitations. We discuss the current and future applications of BoC electrophysiology, also expanding to complementary approaches. We conclude with an evaluation of the potential translational applications and prospective technology developments.
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Affiliation(s)
- Csaba Forro
- Tissue Electronics, Fondazione Istituto Italiano di Tecnologia, Largo Barsanti e Matteucci, 53-80125 Naples, Italy; (C.F.); (F.S.)
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Davide Caron
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| | - Gian Nicola Angotzi
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (G.N.A.); (L.B.)
| | - Vincenzo Gallo
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| | - Luca Berdondini
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (G.N.A.); (L.B.)
| | - Francesca Santoro
- Tissue Electronics, Fondazione Istituto Italiano di Tecnologia, Largo Barsanti e Matteucci, 53-80125 Naples, Italy; (C.F.); (F.S.)
| | - Gemma Palazzolo
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| | - Gabriella Panuccio
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
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25
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Weigand C, Kim SH, Brown E, Medina E, Mares M, Miller G, Harper JF, Choi WG. A Ratiometric Calcium Reporter CGf Reveals Calcium Dynamics Both in the Single Cell and Whole Plant Levels Under Heat Stress. FRONTIERS IN PLANT SCIENCE 2021; 12:777975. [PMID: 34975960 PMCID: PMC8718611 DOI: 10.3389/fpls.2021.777975] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/17/2021] [Indexed: 05/02/2023]
Abstract
Land plants evolved to quickly sense and adapt to temperature changes, such as hot days and cold nights. Given that calcium (Ca2+) signaling networks are implicated in most abiotic stress responses, heat-triggered changes in cytosolic Ca2+ were investigated in Arabidopsis leaves and pollen. Plants were engineered with a reporter called CGf, a ratiometric, genetically encoded Ca2+ reporter with an mCherry reference domain fused to an intensiometric Ca2+ reporter GCaMP6f. Relative changes in [Ca2+]cyt were estimated based on CGf's apparent K D around 220 nM. The ratiometric output provided an opportunity to compare Ca2+ dynamics between different tissues, cell types, or subcellular locations. In leaves, CGf detected heat-triggered cytosolic Ca2+ signals, comprised of three different signatures showing similarly rapid rates of Ca2+ influx followed by differing rates of efflux (50% durations ranging from 5 to 19 min). These heat-triggered Ca2+ signals were approximately 1.5-fold greater in magnitude than blue light-triggered signals in the same leaves. In contrast, growing pollen tubes showed two different heat-triggered responses. Exposure to heat caused tip-focused steady growth [Ca2+]cyt oscillations to shift to a pattern characteristic of a growth arrest (22%), or an almost undetectable [Ca2+]cyt (78%). Together, these contrasting examples of heat-triggered Ca2+ responses in leaves and pollen highlight the diversity of Ca2+ signals in plants, inviting speculations about their differing kinetic features and biological functions.
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Affiliation(s)
- Chrystle Weigand
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Su-Hwa Kim
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Elizabeth Brown
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Emily Medina
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Moises Mares
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Gad Miller
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel
| | - Jeffrey F. Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
- *Correspondence: Jeffrey F. Harper,
| | - Won-Gyu Choi
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
- Won-Gyu Choi,
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26
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Milosevic MM, Jang J, McKimm EJ, Zhu MH, Antic SD. In Vitro Testing of Voltage Indicators: Archon1, ArcLightD, ASAP1, ASAP2s, ASAP3b, Bongwoori-Pos6, BeRST1, FlicR1, and Chi-VSFP-Butterfly. eNeuro 2020; 7:ENEURO.0060-20.2020. [PMID: 32817120 PMCID: PMC7540930 DOI: 10.1523/eneuro.0060-20.2020] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 08/03/2020] [Accepted: 08/09/2020] [Indexed: 01/04/2023] Open
Abstract
Genetically encoded voltage indicators (GEVIs) could potentially be used for mapping neural circuits at the plane of synaptic potentials and plateau potentials-two blind spots of GCaMP-based imaging. In the last year alone, several laboratories reported significant breakthroughs in the quality of GEVIs and the efficacy of the voltage imaging equipment. One major obstacle of using well performing GEVIs in the pursuit of interesting biological data is the process of transferring GEVIs between laboratories, as their reported qualities (e.g., membrane targeting, brightness, sensitivity, optical signal quality) are often difficult to reproduce outside of the laboratory of the GEVI origin. We have tested eight available GEVIs (Archon1, ArcLightD, ASAP1, ASAP2s, ASAP3b, Bongwoori-Pos6, FlicR1, and chi-VSFP-Butterfly) and two voltage-sensitive dyes (BeRST1 and di-4-ANEPPS). We used the same microscope, lens, and optical detector, while the light sources were interchanged. GEVI voltage imaging was attempted in the following three preparations: (1) cultured neurons, (2) HEK293 cells, and (3) mouse brain slices. Systematic measurements were successful only in HEK293 cells and brain slices. Despite the significant differences in brightness and dynamic response (ON rate), all tested indicators produced reasonable optical signals in brain slices and solid in vitro quality properties, in the range initially reported by the creator laboratories. Side-by-side comparisons between GEVIs and organic dyes obtained in HEK293 cells and brain slices by a "third party" (current data) will be useful for determining the right voltage indicator for a given research application.
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Affiliation(s)
- Milena M Milosevic
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
- Center for Laser Microscopy, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Jinyoung Jang
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
| | - Eric J McKimm
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
| | - Mei Hong Zhu
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
| | - Srdjan D Antic
- Institute for Systems Genomics, Department of Neuroscience, UConn School of Medicine, Farmington, Connecticut 06030
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27
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Dingle YTL, Liaudanskaya V, Finnegan LT, Berlind KC, Mizzoni C, Georgakoudi I, Nieland TJF, Kaplan DL. Functional Characterization of Three-Dimensional Cortical Cultures for In Vitro Modeling of Brain Networks. iScience 2020; 23:101434. [PMID: 32805649 PMCID: PMC7452433 DOI: 10.1016/j.isci.2020.101434] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/27/2020] [Accepted: 08/03/2020] [Indexed: 12/22/2022] Open
Abstract
Three-dimensional (3D) in vitro cultures recapitulate key features of the brain including morphology, cell-cell and cell-extracellular matrix interactions, gradients of factors, and mechanical properties. However, there remains a need for experimental and computational tools to investigate network functions in these 3D models. To address this need, we present an experimental system based on 3D scaffold-based cortical neuron cultures in which we expressed the genetically encoded calcium indicator GCaMP6f to record neuronal activity at the millimeter-scale. Functional neural network descriptors were computed with graph-theory-based network analysis methods, showing the formation of functional networks at 3 weeks of culture. Changes to the functional network properties upon perturbations to glutamatergic neurotransmission or GABAergic neurotransmission were quantitatively characterized. The results illustrate the applicability of our 3D experimental system for the study of brain network development, function, and disruption in a biomimetic microenvironment.
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Affiliation(s)
- Yu-Ting L Dingle
- Department of Biomedical Engineering, Tufts University, 200 College Avenue, Medford, MA 02155, USA
| | - Volha Liaudanskaya
- Department of Biomedical Engineering, Tufts University, 200 College Avenue, Medford, MA 02155, USA
| | - Liam T Finnegan
- Department of Biomedical Engineering, Tufts University, 200 College Avenue, Medford, MA 02155, USA
| | - Kyler C Berlind
- Department of Biomedical Engineering, Tufts University, 200 College Avenue, Medford, MA 02155, USA
| | - Craig Mizzoni
- Department of Biomedical Engineering, Tufts University, 200 College Avenue, Medford, MA 02155, USA
| | - Irene Georgakoudi
- Department of Biomedical Engineering, Tufts University, 200 College Avenue, Medford, MA 02155, USA
| | - Thomas J F Nieland
- Department of Biomedical Engineering, Tufts University, 200 College Avenue, Medford, MA 02155, USA
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, 200 College Avenue, Medford, MA 02155, USA.
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28
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Williams PDE, Verma S, Robertson AP, Martin RJ. Adapting techniques for calcium imaging in muscles of adult Brugia malayi. INVERTEBRATE NEUROSCIENCE 2020; 20:12. [PMID: 32803437 DOI: 10.1007/s10158-020-00247-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/06/2020] [Indexed: 02/07/2023]
Abstract
Brugia malayi is a human filarial nematode parasite that causes lymphatic filariasis or 'elephantiasis' a disfiguring neglected tropical disease. This parasite is a more tractable nematode parasite for the experimental study of anthelmintic drugs and has been studied with patch-clamp and RNAi techniques. Unlike in C. elegans however, calcium signaling in B. malayi or other nematode parasites has not been achieved, limiting the studies of the mode of action of anthelmintic drugs. We describe here the development of calcium imaging methods that allow us to characterize changes in cellular calcium in the muscles of B. malayi. This is a powerful technique that can help in elucidating the mode of action of selected anthelmintics. We developed two approaches that allow the recording of calcium signals in the muscles of adult B. malayi: (a) soaking the muscles with Fluo-3AM, promoting large-scale imaging of multiple cells simultaneously and, (b) direct insertion of Fluo-3 using microinjection, providing the possibility of performing dual calcium and electrophysiological recordings. Here, we describe the techniques used to optimize dye entry into the muscle cells and demonstrate that detectable increases in Fluo-3 fluorescence to elevated calcium concentrations can be achieved in B. malayi using both techniques.
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Affiliation(s)
- Paul D E Williams
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Dr, Ames, IA, 50011, USA
| | - Saurabh Verma
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Dr, Ames, IA, 50011, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Dr, Ames, IA, 50011, USA
| | - Richard J Martin
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Dr, Ames, IA, 50011, USA.
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29
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Tran LM, Mocle AJ, Ramsaran AI, Jacob AD, Frankland PW, Josselyn SA. Automated Curation of CNMF-E-Extracted ROI Spatial Footprints and Calcium Traces Using Open-Source AutoML Tools. Front Neural Circuits 2020; 14:42. [PMID: 32792911 PMCID: PMC7384547 DOI: 10.3389/fncir.2020.00042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/19/2020] [Indexed: 11/17/2022] Open
Abstract
In vivo 1-photon (1p) calcium imaging is an increasingly prevalent method in behavioral neuroscience. Numerous analysis pipelines have been developed to improve the reliability and scalability of pre-processing and ROI extraction for these large calcium imaging datasets. Despite these advancements in pre-processing methods, manual curation of the extracted spatial footprints and calcium traces of neurons remains important for quality control. Here, we propose an additional semi-automated curation step for sorting spatial footprints and calcium traces from putative neurons extracted using the popular constrained non-negative matrixfactorization for microendoscopic data (CNMF-E) algorithm. We used the automated machine learning (AutoML) tools TPOT and AutoSklearn to generate classifiers to curate the extracted ROIs trained on a subset of human-labeled data. AutoSklearn produced the best performing classifier, achieving an F1 score >92% on the ground truth test dataset. This automated approach is a useful strategy for filtering ROIs with relatively few labeled data points and can be easily added to pre-existing pipelines currently using CNMF-E for ROI extraction.
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Affiliation(s)
- Lina M. Tran
- Hospital for Sick Children, Neurosciences and Mental Health, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Postgraduate Affiliates Program, Vector Institute, Toronto, ON, Canada
| | - Andrew J. Mocle
- Hospital for Sick Children, Neurosciences and Mental Health, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Adam I. Ramsaran
- Hospital for Sick Children, Neurosciences and Mental Health, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
| | - Alexander D. Jacob
- Hospital for Sick Children, Neurosciences and Mental Health, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
| | - Paul W. Frankland
- Hospital for Sick Children, Neurosciences and Mental Health, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, ON, Canada
| | - Sheena A. Josselyn
- Hospital for Sick Children, Neurosciences and Mental Health, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Brain, Mind & Consciousness Program, Canadian Institute for Advanced Research (CIFAR), Toronto, ON, Canada
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30
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Slaoui Hasnaoui M, Arsenault I, Verdier D, Obeid S, Kolta A. Functional Connectivity Between the Trigeminal Main Sensory Nucleus and the Trigeminal Motor Nucleus. Front Cell Neurosci 2020; 14:167. [PMID: 32655373 PMCID: PMC7324845 DOI: 10.3389/fncel.2020.00167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/19/2020] [Indexed: 11/24/2022] Open
Abstract
The present study shows new evidence of functional connectivity between the trigeminal main sensory (NVsnpr) and motor (NVmt) nuclei in rats and mice. NVsnpr neurons projecting to NVmt are most highly concentrated in its dorsal half. Their electrical stimulation induced multiphasic excitatory synaptic responses in trigeminal MNs and evoked calcium responses mainly in the jaw-closing region of NVmt. Induction of rhythmic bursting in NVsnpr neurons by local applications of BAPTA also elicited rhythmic firing or clustering of postsynaptic potentials in trigeminal motoneurons, further emphasizing the functional relationship between these two nuclei in terms of rhythm transmission. Biocytin injections in both nuclei and calcium-imaging in one of the two nuclei during electrical stimulation of the other revealed a specific pattern of connectivity between the two nuclei, which organization seemed to critically depend on the dorsoventral location of the stimulation site within NVsnpr with the most dorsal areas of NVsnpr projecting to the dorsolateral region of NVmt and intermediate areas projecting to ventromedial NVmt. This study confirms and develops earlier experiments by exploring the physiological nature and functional topography of the connectivity between NVsnpr and NVmt that was demonstrated in the past with neuroanatomical techniques.
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Affiliation(s)
- Mohammed Slaoui Hasnaoui
- Groupe de Recherche sur le Systéme Nerveux Central, Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréeal, QC, Canada
| | - Isabel Arsenault
- Groupe de Recherche sur le Systéme Nerveux Central, Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréeal, QC, Canada
| | - Dorly Verdier
- Groupe de Recherche sur le Systéme Nerveux Central, Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréeal, QC, Canada
| | - Sami Obeid
- Groupe de Recherche sur le Systéme Nerveux Central, Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréeal, QC, Canada
| | - Arlette Kolta
- Groupe de Recherche sur le Systéme Nerveux Central, Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréeal, QC, Canada.,Département de Stomatologie, Faculté de Médecine Dentaire, Université de Montreal, Montreal, QC, Canada
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31
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Tanaka R, Clark DA. Object-Displacement-Sensitive Visual Neurons Drive Freezing in Drosophila. Curr Biol 2020; 30:2532-2550.e8. [PMID: 32442466 PMCID: PMC8716191 DOI: 10.1016/j.cub.2020.04.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/22/2020] [Accepted: 04/24/2020] [Indexed: 11/26/2022]
Abstract
Visual systems are often equipped with neurons that detect small moving objects, which may represent prey, predators, or conspecifics. Although the processing properties of those neurons have been studied in diverse organisms, links between the proposed algorithms and animal behaviors or circuit mechanisms remain elusive. Here, we have investigated behavioral function, computational algorithm, and neurochemical mechanisms of an object-selective neuron, LC11, in Drosophila. With genetic silencing and optogenetic activation, we show that LC11 is necessary for a visual object-induced stopping behavior in walking flies, a form of short-term freezing, and its activity can promote stopping. We propose a new quantitative model for small object selectivity based on the physiology and anatomy of LC11 and its inputs. The model accurately reproduces LC11 responses by pooling fast-adapting, tightly size-tuned inputs. Direct visualization of neurotransmitter inputs to LC11 confirmed the model conjectures about upstream processing. Our results demonstrate how adaptation can enhance selectivity for behaviorally relevant, dynamic visual features.
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Affiliation(s)
- Ryosuke Tanaka
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511, USA
| | - Damon A Clark
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA; Department of Physics, Yale University, New Haven, CT 06511, USA; Department of Neuroscience, Yale University, New Haven, CT 06511, USA.
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32
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Griffiths VA, Valera AM, Lau JY, Roš H, Younts TJ, Marin B, Baragli C, Coyle D, Evans GJ, Konstantinou G, Koimtzis T, Nadella KMNS, Punde SA, Kirkby PA, Bianco IH, Silver RA. Real-time 3D movement correction for two-photon imaging in behaving animals. Nat Methods 2020; 17:741-748. [PMID: 32483335 PMCID: PMC7370269 DOI: 10.1038/s41592-020-0851-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 04/28/2020] [Indexed: 11/09/2022]
Abstract
Two-photon microscopy is widely used to investigate brain function across multiple spatial scales. However, measurements of neural activity are compromised by brain movement in behaving animals. Brain motion-induced artifacts are typically corrected using post hoc processing of two-dimensional images, but this approach is slow and does not correct for axial movements. Moreover, the deleterious effects of brain movement on high-speed imaging of small regions of interest and photostimulation cannot be corrected post hoc. To address this problem, we combined random-access three-dimensional (3D) laser scanning using an acousto-optic lens and rapid closed-loop field programmable gate array processing to track 3D brain movement and correct motion artifacts in real time at up to 1 kHz. Our recordings from synapses, dendrites and large neuronal populations in behaving mice and zebrafish demonstrate real-time movement-corrected 3D two-photon imaging with submicrometer precision.
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Affiliation(s)
- Victoria A Griffiths
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Antoine M Valera
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Joanna Yn Lau
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Hana Roš
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Thomas J Younts
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Bóris Marin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, Brazil
| | - Chiara Baragli
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- , Paris, France
| | - Diccon Coyle
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Geoffrey J Evans
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- Department of Engineering, Sencon (UK) Ltd., Droitwich, UK
| | - George Konstantinou
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- The Francis Crick Institute, London, UK
| | - Theo Koimtzis
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- Optical Metrology Service, Stansted, UK
| | | | - Sameer A Punde
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Paul A Kirkby
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Isaac H Bianco
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - R Angus Silver
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK.
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33
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Chen M, Mu L, Wang S, Cao X, Liang S, Wang Y, She G, Yang J, Wang Y, Shi W. A Single Silicon Nanowire-Based Ratiometric Biosensor for Ca 2+ at Various Locations in a Neuron. ACS Chem Neurosci 2020; 11:1283-1290. [PMID: 32293869 DOI: 10.1021/acschemneuro.0c00041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Ionic calcium (Ca2+) is an important second messenger in cells, particularly in the neuron. A deficiency or excess of Ca2+ would lead to neuronal apoptosis and further injury to the brain. For accurate analysis of intracellular Ca2+, a single silicon nanowire (SiNW)-based ratiometric biosensor was constructed by simultaneously anchoring Ru(bpy)2(mcbpy-O-Su-ester)(PF6)2, as a reference molecule, and Fluo-3, as a response molecule, onto the surface of a single SiNW. The SiNW-based biosensor exhibits high sensitivity and favorable selectivity for detecting Ca2+. With the assistance of a micromanipulator and laser scanning confocal microscope, two single SiNW sensors were placed in the body and the neurites of an individual neuron to detect Ca2+. The difference between the concentrations of Ca2+ in the body and neurites was identified. The results from the present study provide new insights into Ca2+ in neurons at a high spatial resolution, and the strategy used in this study provides a new opportunity to investigate cellular metabolism by combining the advantages of a single-cell detection technique and physiology.
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Affiliation(s)
- Min Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lixuan Mu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Shuai Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institutes of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China
| | - Xingxing Cao
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sen Liang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guangwei She
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Jun Yang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institutes of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China
| | - Yongan Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institutes of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China
| | - Wensheng Shi
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Tang S, Deng X, Jiang J, Kirberger M, Yang JJ. Design of Calcium-Binding Proteins to Sense Calcium. Molecules 2020; 25:molecules25092148. [PMID: 32375353 PMCID: PMC7248937 DOI: 10.3390/molecules25092148] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 01/25/2023] Open
Abstract
Calcium controls numerous biological processes by interacting with different classes of calcium binding proteins (CaBP’s), with different affinities, metal selectivities, kinetics, and calcium dependent conformational changes. Due to the diverse coordination chemistry of calcium, and complexity associated with protein folding and binding cooperativity, the rational design of CaBP’s was anticipated to present multiple challenges. In this paper we will first discuss applications of statistical analysis of calcium binding sites in proteins and subsequent development of algorithms to predict and identify calcium binding proteins. Next, we report efforts to identify key determinants for calcium binding affinity, cooperativity and calcium dependent conformational changes using grafting and protein design. Finally, we report recent advances in designing protein calcium sensors to capture calcium dynamics in various cellular environments.
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Affiliation(s)
- Shen Tang
- Department of Chemistry, Center for Diagnostics and Therapeutics and Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA; (S.T.); (X.D.); (J.J.)
| | - Xiaonan Deng
- Department of Chemistry, Center for Diagnostics and Therapeutics and Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA; (S.T.); (X.D.); (J.J.)
| | - Jie Jiang
- Department of Chemistry, Center for Diagnostics and Therapeutics and Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA; (S.T.); (X.D.); (J.J.)
| | - Michael Kirberger
- School of Science and Technology, Georgia Gwinnett College, Lawrenceville, GA 30043, USA;
| | - Jenny J. Yang
- Department of Chemistry, Center for Diagnostics and Therapeutics and Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA; (S.T.); (X.D.); (J.J.)
- Correspondence: ; Tel.: +1-404-413-5520
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Andreoni A, Davis CM, Tian L. Measuring brain chemistry using genetically encoded fluorescent sensors. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2019. [DOI: 10.1016/j.cobme.2019.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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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: 8.2] [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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Gould TW, Swope WA, Heredia DJ, Corrigan RD, Smith TK. Activity within specific enteric neurochemical subtypes is correlated with distinct patterns of gastrointestinal motility in the murine colon. Am J Physiol Gastrointest Liver Physiol 2019; 317:G210-G221. [PMID: 31268770 PMCID: PMC6734370 DOI: 10.1152/ajpgi.00252.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The enteric nervous system in the large intestine generates two important patterns relating to motility: 1) propagating rhythmic peristaltic smooth muscle contractions referred to as colonic migrating motor complexes (CMMCs) and 2) tonic inhibition, during which colonic smooth muscle contractions are suppressed. The precise neurobiological substrates underlying each of these patterns are unclear. Using transgenic animals expressing the genetically encoded calcium indicator GCaMP3 to monitor activity or the optogenetic actuator channelrhodopsin (ChR2) to drive activity in defined enteric neuronal subpopulations, we provide evidence that cholinergic and nitrergic neurons play significant roles in mediating CMMCs and tonic inhibition, respectively. Nitrergic neurons [neuronal nitric oxide synthase (nNOS)-positive neurons] expressing GCaMP3 exhibited higher levels of activity during periods of tonic inhibition than during CMMCs. Consistent with these findings, optogenetic activation of ChR2 in nitrergic neurons depressed ongoing CMMCs. Conversely, cholinergic neurons [choline acetyltransferase (ChAT)-positive neurons] expressing GCaMP3 markedly increased their activity during the CMMC. Treatment with the NO synthesis inhibitor Nω-nitro-l-arginine also augmented the activity of ChAT-GCaMP3 neurons, suggesting that the reciprocal patterns of activity exhibited by nitrergic and cholinergic enteric neurons during distinct phases of colonic motility may be related.NEW & NOTEWORTHY Correlating the activity of neuronal populations in the myenteric plexus to distinct periods of gastrointestinal motility is complicated by the difficulty of measuring the activity of specific neuronal subtypes. Here, using mice expressing genetically encoded calcium indicators or the optical actuator channelrhodopsin-2, we provide compelling evidence that cholinergic and nitrergic neurons play important roles in mediating coordinated propagating peristaltic contractions or tonic inhibition, respectively, in the murine colon.
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Affiliation(s)
- Thomas W. Gould
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine, Reno, Nevada
| | - William A. Swope
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine, Reno, Nevada
| | - Dante J. Heredia
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine, Reno, Nevada
| | - Robert D. Corrigan
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine, Reno, Nevada
| | - Terence K. Smith
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine, Reno, Nevada
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Suk HJ, Boyden ES, van Welie I. Advances in the automation of whole-cell patch clamp technology. J Neurosci Methods 2019; 326:108357. [PMID: 31336060 DOI: 10.1016/j.jneumeth.2019.108357] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/05/2019] [Accepted: 07/10/2019] [Indexed: 12/22/2022]
Abstract
Electrophysiology is the study of neural activity in the form of local field potentials, current flow through ion channels, calcium spikes, back propagating action potentials and somatic action potentials, all measurable on a millisecond timescale. Despite great progress in imaging technologies and sensor proteins, none of the currently available tools allow imaging of neural activity on a millisecond timescale and beyond the first few hundreds of microns inside the brain. The patch clamp technique has been an invaluable tool since its inception several decades ago and has generated a wealth of knowledge about the nature of voltage- and ligand-gated ion channels, sub-threshold and supra-threshold activity, and characteristics of action potentials related to higher order functions. Many techniques that evolve to be standardized tools in the biological sciences go through a period of transformation in which they become, at least to some degree, automated, in order to improve reproducibility, throughput and standardization. The patch clamp technique is currently undergoing this transition, and in this review, we will discuss various aspects of this transition, covering advances in automated patch clamp technology both in vitro and in vivo.
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Affiliation(s)
- Ho-Jun Suk
- Health Sciences and Technology, MIT, Cambridge, MA 02139, USA; Media Lab, MIT, Cambridge, MA 02139, USA; McGovern Institute, MIT, Cambridge, MA 02139, USA
| | - Edward S Boyden
- Media Lab, MIT, Cambridge, MA 02139, USA; McGovern Institute, MIT, Cambridge, MA 02139, USA; Department of Biological Engineering, MIT, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA
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39
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High-performance calcium sensors for imaging activity in neuronal populations and microcompartments. Nat Methods 2019; 16:649-657. [DOI: 10.1038/s41592-019-0435-6] [Citation(s) in RCA: 512] [Impact Index Per Article: 102.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 04/30/2019] [Indexed: 02/07/2023]
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40
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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: 140] [Impact Index Per Article: 28.0] [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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41
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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: 17] [Impact Index Per Article: 3.4] [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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42
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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: 2.4] [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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43
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Fontaine AK, Segil JL, Caldwell JH, Weir RFF. Real-Time Prosthetic Digit Actuation by Optical Read-out of Activity-Dependent Calcium Signals in an Ex Vivo Peripheral Nerve. INTERNATIONAL IEEE/EMBS CONFERENCE ON NEURAL ENGINEERING : [PROCEEDINGS]. INTERNATIONAL IEEE EMBS CONFERENCE ON NEURAL ENGINEERING 2019; 2019:143-146. [PMID: 38566861 PMCID: PMC10984832 DOI: 10.1109/ner.2019.8717033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Improved neural interfacing strategies are needed for the full articulation of advanced prostheses. To address limitations of existing control interface designs, the work of our laboratory has presented an optical approach to reading activity from individual nerve fibers using activity-dependent calcium transients. Here, we demonstrate the feasibility of such signals to control prosthesis actuation by using the axonal fluorescence signal in an ex vivo mouse nerve to drive a prosthetic digit in real-time. Additionally, signals of varying action potential frequency are streamed post hoc to the prosthesis, showing graded motor output and the potential for proportional neural control. This proof-of-concept work is a novel demonstration of the functional use of activity-dependent optical read-out in the nerve.
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Affiliation(s)
- Arjun K Fontaine
- Department of Bioengineering, University of Colorado | Anschutz Medical Campus, Aurora, CO 80045 USA
| | - Jacob L Segil
- Engineering Plus Program, University of Colorado Boulder, Boulder, CO, 80309 USA
| | - John H Caldwell
- Department of Cell and Developmental Biology, University of Colorado | Anschutz Medical Campus, Aurora, CO 80045 USA
| | - Richard F Ff Weir
- Department of Bioengineering, University of Colorado | Anschutz Medical Campus, Aurora, CO 80045 USA
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44
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Brodskiy PA, Wu Q, Soundarrajan DK, Huizar FJ, Chen J, Liang P, Narciso C, Levis MK, Arredondo-Walsh N, Chen DZ, Zartman JJ. Decoding Calcium Signaling Dynamics during Drosophila Wing Disc Development. Biophys J 2019; 116:725-740. [PMID: 30704858 PMCID: PMC6382932 DOI: 10.1016/j.bpj.2019.01.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 12/04/2018] [Accepted: 01/04/2019] [Indexed: 01/07/2023] Open
Abstract
The robust specification of organ development depends on coordinated cell-cell communication. This process requires signal integration among multiple pathways, relying on second messengers such as calcium ions. Calcium signaling encodes a significant portion of the cellular state by regulating transcription factors, enzymes, and cytoskeletal proteins. However, the relationships between the inputs specifying cell and organ development, calcium signaling dynamics, and final organ morphology are poorly understood. Here, we have designed a quantitative image-analysis pipeline for decoding organ-level calcium signaling. With this pipeline, we extracted spatiotemporal features of calcium signaling dynamics during the development of the Drosophila larval wing disc, a genetic model for organogenesis. We identified specific classes of wing phenotypes that resulted from calcium signaling pathway perturbations, including defects in gross morphology, vein differentiation, and overall size. We found four qualitative classes of calcium signaling activity. These classes can be ordered based on agonist stimulation strength Gαq-mediated signaling. In vivo calcium signaling dynamics depend on both receptor tyrosine kinase/phospholipase C γ and G protein-coupled receptor/phospholipase C β activities. We found that spatially patterned calcium dynamics correlate with known differential growth rates between anterior and posterior compartments. Integrated calcium signaling activity decreases with increasing tissue size, and it responds to morphogenetic perturbations that impact organ growth. Together, these findings define how calcium signaling dynamics integrate upstream inputs to mediate multiple response outputs in developing epithelial organs.
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Affiliation(s)
- Pavel A Brodskiy
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Qinfeng Wu
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Dharsan K Soundarrajan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Francisco J Huizar
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Jianxu Chen
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Peixian Liang
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Cody Narciso
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Megan K Levis
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | | | - Danny Z Chen
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Jeremiah J Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana.
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45
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Albers F, Wachsmuth L, van Alst TM, Faber C. Multimodal Functional Neuroimaging by Simultaneous BOLD fMRI and Fiber-Optic Calcium Recordings and Optogenetic Control. Mol Imaging Biol 2019; 20:171-182. [PMID: 29027094 DOI: 10.1007/s11307-017-1130-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Recent developments of optogenetic tools and fluorescence-based calcium recording techniques enable the manipulation and monitoring of neural circuits on a cellular level. Non-invasive imaging of brain networks, however, requires the application of methods such as blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI), which is commonly used for functional neuroimaging. While BOLD fMRI provides brain-wide non-invasive reading of the hemodynamic response, it is only an indirect measure of neural activity. Direct observation of neural responses requires electrophysiological or optical methods. The latter can be combined with optogenetic control of neuronal circuits and are MRI compatible. Yet, simultaneous optical recordings are still limited to fiber-optic-based approaches. Here, we review the integration of optical recordings and optogenetic manipulation into fMRI experiments. As a practical example, we describe how BOLD fMRI in a 9.4-T small animal MR scanner can be combined with in vivo fiber-optic calcium recordings and optogenetic control in a multimodal setup. We present simultaneous BOLD fMRI and calcium recordings under optogenetic control in rat. We outline details about MR coil configuration, choice, and usage of opsins and chemically and genetically encoded calcium sensors, fiber implantation, appropriate light power for stimulation, and calcium signal detection, to provide a glimpse into challenges and opportunities of this multimodal molecular neuroimaging approach.
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Affiliation(s)
- Franziska Albers
- Department of Clinical Radiology, University Hospital Münster, Münster, Germany
| | - Lydia Wachsmuth
- Department of Clinical Radiology, University Hospital Münster, Münster, Germany
| | | | - Cornelius Faber
- Department of Clinical Radiology, University Hospital Münster, Münster, Germany.
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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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47
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Soleja N, Manzoor O, Khan I, Ahmad A, Mohsin M. Role of green fluorescent proteins and their variants in development of FRET-based sensors. J Biosci 2018; 43:763-784. [PMID: 30207321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Since the last decade, a lot of advancement has been made to understand biological processes involving complex intracellular pathways. The major challenge faced was monitoring and trafficking of metabolites in real time. Although a range of quantitative and imaging techniques have been developed so far, the discovery of green fluorescent proteins (GFPs) has revolutionized the advancement in the field of metabolomics. GFPs and their variants have enabled researchers to 'paint' a wide range of biological molecules. Fluorescence resonance energy transfer (FRET)-based genetically encoded sensors is a promising technology to decipher the real-time monitoring of the cellular events inside living cells. GFPs and their variants, due to their intrinsic fluorescence properties, are extensively being used nowadays in cell-based assays. This review focuses on structure and function of GFP and its derivatives, mechanism emission and their use in the development of FRET-based sensors for metabolites.
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Affiliation(s)
- Neha Soleja
- Department of Biosciences, Jamia Millia Islamia, New Delhi 110 025, India
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48
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Soleja N, Manzoor O, Khan I, Ahmad A, Mohsin M. Role of green fluorescent proteins and their variants in development of FRET-based sensors. J Biosci 2018. [DOI: 10.1007/s12038-018-9783-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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49
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Lu Y, Liu X, Hattori R, Ren C, Zhang X, Komiyama T, Kuzum D. Ultra-low Impedance Graphene Microelectrodes with High Optical Transparency for Simultaneous Deep 2-photon Imaging in Transgenic Mice. ADVANCED FUNCTIONAL MATERIALS 2018; 28:1800002. [PMID: 34084100 PMCID: PMC8172040 DOI: 10.1002/adfm.201800002] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Indexed: 05/27/2023]
Abstract
The last decades have witnessed substantial progress in optical technologies revolutionizing our ability to record and manipulate neural activity in genetically modified animal models. Meanwhile, human studies mostly rely on electrophysiological recordings of cortical potentials, which cannot be inferred from optical recordings, leading to a gap between our understanding of dynamics of microscale populations and brain-scale neural activity. By enabling concurrent integration of electrical and optical modalities, transparent graphene microelectrodes can close this gap. However, the high impedance of graphene constitutes a big challenge towards the widespread use of this technology. Here, we experimentally demonstrate that this high impedance of graphene microelectrodes is fundamentally limited by quantum capacitance. We overcome this quantum capacitance limit by creating a parallel conduction path using platinum nanoparticles. We achieve a 100 times reduction in graphene electrode impedance, while maintaining the high optical transparency crucial for deep 2-photon microscopy. Using a transgenic mouse model, we demonstrate simultaneous electrical recording of cortical activity with high fidelity while imaging calcium signals at various cortical depths right beneath the transparent microelectrodes. Multimodal analysis of Ca2+ spikes and cortical surface potentials offers unique opportunities to bridge our understanding of cellular dynamics and brain-scale neural activity.
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Affiliation(s)
- Yichen Lu
- 9500 Gilman Drive, Electrical and Computer Engineering Department, Jacobs School of Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Xin Liu
- 9500 Gilman Drive, Electrical and Computer Engineering Department, Jacobs School of Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Ryoma Hattori
- 9500 Gilman Drive, Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Chi Ren
- 9500 Gilman Drive, Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xingwang Zhang
- 9500 Gilman Drive, Nanoengineering Department, Jacobs School of Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Takaki Komiyama
- 9500 Gilman Drive, Neurobiology Section, Center for Neural Circuits and Behavior, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Duygu Kuzum
- 9500 Gilman Drive, Electrical and Computer Engineering Department, Jacobs School of Engineering, University of California, San Diego, La Jolla, California 92093, USA
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Singh M, Lujan B, Renden R. Presynaptic GCaMP expression decreases vesicle release probability at the calyx of Held. Synapse 2018; 72:e22040. [PMID: 29935099 PMCID: PMC6186185 DOI: 10.1002/syn.22040] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 12/15/2022]
Abstract
Synaptic vesicle (SV) exocytosis is intimately dependent on free local Ca2+ near active zones. Genetically encoded calcium indicators (GECIs) have become an indispensable tool to monitor calcium dynamics during physiological responses, and they are widely used as a proxy to monitor activity in neuronal ensembles and at synaptic terminals. However, GECIs’ ability to bind Ca2+ at physiologically relevant concentration makes them strong candidates to affect calcium homeostasis and alter synaptic transmission by exogenously increasing Ca2+ buffering. In the present study, we show that genetically expressed GCaMP6m modulates SV release probability at the mouse calyx of Held synapse. GCaMP6m expression for approximately three weeks decreased initial SV release for both low‐frequency stimulation and high‐frequency stimulation trains, and slowed presynaptic short‐term depression. However, GCaMP6m does not affect quantal events during spontaneous activity at this synapse. This study emphasizes the careful use of GECIs as monitors of neuronal activity and inspects the role of these transgenic indicators which may alter calcium‐dependent physiological responses.
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Affiliation(s)
- Mahendra Singh
- Department of Physiology and Cell Biology, University of Nevada, Reno, Nevada, 89557
| | - Brendan Lujan
- Department of Physiology and Cell Biology, University of Nevada, Reno, Nevada, 89557.,Currently at Vollum Institute, Oregon Health and Science University, Portland, Oregon
| | - Robert Renden
- Department of Physiology and Cell Biology, University of Nevada, Reno, Nevada, 89557
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