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Zhan J, Fang F, Tian D, Li H. Anthraquinone-modified calix[4]arene: click synthesis, selective calcium ion fluorescent chemosensor and INHIBIT logic gate. Supramol Chem 2012. [DOI: 10.1080/10610278.2012.656124] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Junyan Zhan
- a Country Key Laboratory of Pesticide and Chemical Biology of the Ministry of Education, College of Chemistry, Central China Normal University , Wuhan , P.R. China
| | - Fei Fang
- a Country Key Laboratory of Pesticide and Chemical Biology of the Ministry of Education, College of Chemistry, Central China Normal University , Wuhan , P.R. China
| | - Demei Tian
- a Country Key Laboratory of Pesticide and Chemical Biology of the Ministry of Education, College of Chemistry, Central China Normal University , Wuhan , P.R. China
| | - Haibing Li
- a Country Key Laboratory of Pesticide and Chemical Biology of the Ministry of Education, College of Chemistry, Central China Normal University , Wuhan , P.R. China
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152
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153
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Riemensperger T, Pech U, Dipt S, Fiala A. Optical calcium imaging in the nervous system of Drosophila melanogaster. Biochim Biophys Acta Gen Subj 2012; 1820:1169-78. [PMID: 22402253 DOI: 10.1016/j.bbagen.2012.02.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/21/2012] [Accepted: 02/22/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Drosophila melanogaster is one of the best-studied model organisms in biology, mainly because of the versatility of methods by which heredity and specific expression of genes can be traced and manipulated. Sophisticated genetic tools have been developed to express transgenes in selected cell types, and these techniques can be utilized to target DNA-encoded fluorescence probes to genetically defined subsets of neurons. Neuroscientists make use of this approach to monitor the activity of restricted types or subsets of neurons in the brain and the peripheral nervous system. Since membrane depolarization is typically accompanied by an increase in intracellular calcium ions, calcium-sensitive fluorescence proteins provide favorable tools to monitor the spatio-temporal activity across groups of neurons. SCOPE OF REVIEW Here we describe approaches to perform optical calcium imaging in Drosophila in consideration of various calcium sensors and expression systems. In addition, we outline by way of examples for which particular neuronal systems in Drosophila optical calcium imaging have been used. Finally, we exemplify briefly how optical calcium imaging in the brain of Drosophila can be carried out in practice. MAJOR CONCLUSIONS AND GENERAL SIGNIFICANCE Drosophila provides an excellent model organism to combine genetic expression systems with optical calcium imaging in order to investigate principles of sensory coding, neuronal plasticity, and processing of neuronal information underlying behavior. This article is part of a Special Issue entitled Biochemical, Biophysical and Genetic Approaches to Intracellular Calcium Signaling.
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Affiliation(s)
- Thomas Riemensperger
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Georg-August-University of Goettingen, Goettingen, Germany.
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154
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Excitation spectra and brightness optimization of two-photon excited probes. Biophys J 2012; 102:934-44. [PMID: 22385865 DOI: 10.1016/j.bpj.2011.12.056] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 12/05/2011] [Accepted: 12/07/2011] [Indexed: 11/21/2022] Open
Abstract
Two-photon probe excitation data are commonly presented as absorption cross section or molecular brightness (the detected fluorescence rate per molecule). We report two-photon molecular brightness spectra for a diverse set of organic and genetically encoded probes with an automated spectroscopic system based on fluorescence correlation spectroscopy. The two-photon action cross section can be extracted from molecular brightness measurements at low excitation intensities, while peak molecular brightness (the maximum molecular brightness with increasing excitation intensity) is measured at higher intensities at which probe photophysical effects become significant. The spectral shape of these two parameters was similar across all dye families tested. Peak molecular brightness spectra, which can be obtained rapidly and with reduced experimental complexity, can thus serve as a first-order approximation to cross-section spectra in determining optimal wavelengths for two-photon excitation, while providing additional information pertaining to probe photostability. The data shown should assist in probe choice and experimental design for multiphoton microscopy studies. Further, we show that, by the addition of a passive pulse splitter, nonlinear bleaching can be reduced--resulting in an enhancement of the fluorescence signal in fluorescence correlation spectroscopy by a factor of two. This increase in fluorescence signal, together with the observed resemblance of action cross section and peak brightness spectra, suggests higher-order photobleaching pathways for two-photon excitation.
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155
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Aramuni G, Griesbeck O. Chronic calcium imaging in neuronal development and disease. Exp Neurol 2012; 242:50-6. [PMID: 22374357 DOI: 10.1016/j.expneurol.2012.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 12/05/2011] [Accepted: 02/13/2012] [Indexed: 12/12/2022]
Abstract
Neuronal circuits develop, adjust to experience and degenerate in response to injury or disease in the course of weeks and months. Available recording techniques, however, typically sample physiological properties of identified neurons on the time scale of minutes and hours. Thus, in order to obtain a full understanding of a long term physiological process data need to be extrapolated from numerous experimental sessions and animals, often collected blindly and under variable conditions. The generation and ongoing engineering of genetically encoded calcium indicators creates an opportunity to repeatedly record activity from the same individual neurons in vivo over weeks, months and potentially the entire lifetime of a model organism. Chronic calcium imaging with genetically encoded indicators thus may allow to establish functional biographies of identified neuronal cell types in the brain and to reveal the physiological relevance of structural changes as they occur under natural and pathological conditions.
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Affiliation(s)
- Gayane Aramuni
- Max-Planck-Institut für Neurobiologie, Am Klopferspitz 18, 82152 Martinsried, Germany
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156
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Del Bene F, Wyart C. Optogenetics: A new enlightenment age for zebrafish neurobiology. Dev Neurobiol 2012; 72:404-14. [DOI: 10.1002/dneu.20914] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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157
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Marvin JS, Schreiter ER, Echevarría IM, Looger LL. A genetically encoded, high-signal-to-noise maltose sensor. Proteins 2012; 79:3025-36. [PMID: 21989929 PMCID: PMC3265398 DOI: 10.1002/prot.23118] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We describe the generation of a family of high-signal-to-noise single-wavelength genetically encoded indicators for maltose. This was achieved by insertion of circularly permuted fluorescent proteins into a bacterial periplasmic binding protein (PBP), Escherichia coli maltodextrin-binding protein, resulting in a four-color family of maltose indicators. The sensors were iteratively optimized to have sufficient brightness and maltose-dependent fluorescence increases for imaging, under both one- and two-photon illumination. We demonstrate that maltose affinity of the sensors can be tuned in a fashion largely independent of the fluorescent readout mechanism. Using literature mutations, the binding specificity could be altered to moderate sucrose preference, but with a significant loss of affinity. We use the soluble sensors in individual E. coli bacteria to observe rapid maltose transport across the plasma membrane, and membrane fusion versions of the sensors on mammalian cells to visualize the addition of maltose to extracellular media. The PBP superfamily includes scaffolds specific for a number of analytes whose visualization would be critical to the reverse engineering of complex systems such as neural networks, biosynthetic pathways, and signal transduction cascades. We expect the methodology outlined here to be useful in the development of indicators for many such analytes.
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Affiliation(s)
- Jonathan S Marvin
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, USA.
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158
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Mehlmer N, Parvin N, Hurst CH, Knight MR, Teige M, Vothknecht UC. A toolset of aequorin expression vectors for in planta studies of subcellular calcium concentrations in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1751-61. [PMID: 22213817 PMCID: PMC3971373 DOI: 10.1093/jxb/err406] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Calcium has long been acknowledged as one of the most important signalling components in plants. Many abiotic and biotic stimuli are transduced into a cellular response by temporal and spatial changes in cellular calcium concentration and the calcium-sensitive protein aequorin has been exploited as a genetically encoded calcium indicator for the measurement of calcium in planta. The objective of this work was to generate a compatible set of aequorin expression plasmids for the generation of transgenic plant lines to measure changes in calcium levels in different cellular subcompartments. Aequorin was fused to different targeting peptides or organellar proteins as a means to localize it to the cytosol, the nucleus, the plasma membrane, and the mitochondria. Furthermore, constructs were designed to localize aequorin in the stroma as well as the inner and outer surface of the chloroplast envelope membranes. The modular set-up of the plasmids also allows the easy replacement of targeting sequences to include other compartments. An additional YFP-fusion was included to verify the correct subcellular localization of all constructs by laser scanning confocal microscopy. For each construct, pBin19-based binary expression vectors driven by the 35S or UBI10 promoter were made for Agrobacterium-mediated transformation. Stable Arabidopsis lines were generated and initial tests of several lines confirmed their feasibility to measure calcium signals in vivo.
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Affiliation(s)
- Norbert Mehlmer
- Department of Biology I, Botany, LMU Munich, Großhaderner Str. 2-4, D-82152 Planegg, Germany
| | - Nargis Parvin
- Department of Biology I, Botany, LMU Munich, Großhaderner Str. 2-4, D-82152 Planegg, Germany
| | - Charlotte H. Hurst
- Plant Stress Laboratory, Durham Centre for Crop Improvement Technology, School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Marc R. Knight
- Plant Stress Laboratory, Durham Centre for Crop Improvement Technology, School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Markus Teige
- Department of Biochemistry, MFPL, University of Vienna, Dr. Bohr Gasse 9/5, A-1030 Vienna, Austria
| | - Ute C. Vothknecht
- Department of Biology I, Botany, LMU Munich, Großhaderner Str. 2-4, D-82152 Planegg, Germany
- Centre for Integrated Protein Science (Munich) at the Department of Biology of the LMU Munich, D-81377 Munich, Germany
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159
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160
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Okumoto S, Jones A, Frommer WB. Quantitative imaging with fluorescent biosensors. ANNUAL REVIEW OF PLANT BIOLOGY 2012; 63:663-706. [PMID: 22404462 DOI: 10.1146/annurev-arplant-042110-103745] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Molecular activities are highly dynamic and can occur locally in subcellular domains or compartments. Neighboring cells in the same tissue can exist in different states. Therefore, quantitative information on the cellular and subcellular dynamics of ions, signaling molecules, and metabolites is critical for functional understanding of organisms. Mass spectrometry is generally used for monitoring ions and metabolites; however, its temporal and spatial resolution are limited. Fluorescent proteins have revolutionized many areas of biology-e.g., fluorescent proteins can report on gene expression or protein localization in real time-yet promoter-based reporters are often slow to report physiologically relevant changes such as calcium oscillations. Therefore, novel tools are required that can be deployed in specific cells and targeted to subcellular compartments in order to quantify target molecule dynamics directly. We require tools that can measure enzyme activities, protein dynamics, and biophysical processes (e.g., membrane potential or molecular tension) with subcellular resolution. Today, we have an extensive suite of tools at our disposal to address these challenges, including translocation sensors, fluorescence-intensity sensors, and Förster resonance energy transfer sensors. This review summarizes sensor design principles, provides a database of sensors for more than 70 different analytes/processes, and gives examples of applications in quantitative live cell imaging.
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Affiliation(s)
- Sakiko Okumoto
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA 24061, USA
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161
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Wong SS, Kotera I, Mills E, Suzuki H, Truong K. Split-intein mediated re-assembly of genetically encoded Ca2+ indicators. Cell Calcium 2012; 51:57-64. [DOI: 10.1016/j.ceca.2011.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 10/19/2011] [Accepted: 10/27/2011] [Indexed: 10/14/2022]
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162
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He Y, Wu Y, Mishra A, Acha V, Andrews T, Hornsby PJ. Biosensor technology in aging research and age-related diseases. Ageing Res Rev 2012; 11:1-9. [PMID: 22115588 DOI: 10.1016/j.arr.2011.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Revised: 10/31/2011] [Accepted: 11/04/2011] [Indexed: 11/30/2022]
Abstract
Cell- and tissue-based biosensors comprise genetically engineered proteins that are incorporated into cells ex vivo or into cells of tissues in vivo. They enable the investigator to sense levels of hormones, drugs, or toxins, continuously and noninvasively, using biophotonics or other physical principles, and could potentially be used over the entire lifespan of an experimental animal. The present work reviews the state of the art of cell- and tissue-based biosensors and discusses how they could be of value in aging research. Examples of recently developed biosensors are given, including those that detect levels of a cytokine (TNFα) and drugs (activators of the mTOR pathway). Finally, we discuss the hurdles that would have to be overcome for biosensor technology to be used in humans in monitoring health status and disease treatment in late life.
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Affiliation(s)
- Yulong He
- College of Life Science, Ningxia University, Yinchuan, China.
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163
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Abstract
A major challenge in neuroscience is to understand how universal behaviors, such as sensation, movement, cognition, and emotion, arise from the interactions of specific cells that are present within intricate neural networks in the brain. Dissection of such complex networks has typically relied on disturbing the activity of individual gene products, perturbing neuronal activities pharmacologically, or lesioning specific brain regions, to investigate the network's response in a behavioral output. Though informative for many kinds of studies, these approaches are not sufficiently fine-tuned for examining the functionality of specific cells or cell classes in a spatially or temporally restricted context. Recent advances in the field of optogenetics now enable researchers to monitor and manipulate the activity of genetically defined cell populations with the speed and precision uniquely afforded by light. Transgenic mice engineered to express optogenetic tools in a cell type-specific manner offer a powerful approach for examining the role of particular cells in discrete circuits in a defined and reproducible way. Not surprisingly then, recent years have seen substantial efforts directed toward generating transgenic mouse lines that express functionally relevant levels of optogenetic tools. In this chapter, we review the state of these efforts and consider aspects of the current technology that would benefit from additional improvement.
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Affiliation(s)
- Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA, USA.
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164
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165
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In vivo biochemistry: quantifying ion and metabolite levels in individual cells or cultures of yeast. Biochem J 2011; 438:1-10. [PMID: 21793803 DOI: 10.1042/bj20110428] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Over the past decade, we have learned that cellular processes, including signalling and metabolism, are highly compartmentalized, and that relevant changes in metabolic state can occur at sub-second timescales. Moreover, we have learned that individual cells in populations, or as part of a tissue, exist in different states. If we want to understand metabolic processes and signalling better, it will be necessary to measure biochemical and biophysical responses of individual cells with high temporal and spatial resolution. Fluorescence imaging has revolutionized all aspects of biology since it has the potential to provide information on the cellular and subcellular distribution of ions and metabolites with sub-second time resolution. In the present review we summarize recent progress in quantifying ions and metabolites in populations of yeast cells as well as in individual yeast cells with the help of quantitative fluorescent indicators, namely FRET metabolite sensors. We discuss the opportunities and potential pitfalls and the controls that help preclude misinterpretation.
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166
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Yamada Y, Michikawa T, Hashimoto M, Horikawa K, Nagai T, Miyawaki A, Häusser M, Mikoshiba K. Quantitative comparison of genetically encoded Ca indicators in cortical pyramidal cells and cerebellar Purkinje cells. Front Cell Neurosci 2011; 5:18. [PMID: 21994490 PMCID: PMC3182323 DOI: 10.3389/fncel.2011.00018] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 09/11/2011] [Indexed: 11/13/2022] Open
Abstract
Genetically encoded Ca2+ indicators (GECIs) are promising tools for cell type-specific and chronic recording of neuronal activity. In the mammalian central nervous system, however, GECIs have been tested almost exclusively in cortical and hippocampal pyramidal cells, and the usefulness of recently developed GECIs has not been systematically examined in other cell types. Here we expressed the latest series of GECIs, yellow cameleon (YC) 2.60, YC3.60, YC-Nano15, and GCaMP3, in mouse cortical pyramidal cells as well as cerebellar Purkinje cells using in utero injection of recombinant adenoviral vectors. We characterized the performance of the GECIs by simultaneous two-photon imaging and whole-cell patch-clamp recording in acute brain slices at 33 ± 2°C. The fluorescent responses of GECIs to action potentials (APs) evoked by somatic current injection or to synaptic stimulation were examined using rapid dendritic imaging. In cortical pyramidal cells, YC2.60 showed the largest responses to single APs, but its decay kinetics were slower than YC3.60 and GCaMP3, while GCaMP3 showed the largest responses to 20 APs evoked at 20 Hz. In cerebellar Purkinje cells, only YC2.60 and YC-Nano15 could reliably report single complex spikes (CSs), and neither showed signal saturation over the entire stimulus range tested (1–10 CSs at 10 Hz). The expression and response of YC2.60 in Purkinje cells remained detectable and comparable for at least over 100 days. These results provide useful information for selecting an optimal GECI depending on the experimental requirements: in cortical pyramidal cells, YC2.60 is suitable for detecting sparse firing of APs, whereas GCaMP3 is suitable for detecting burst firing of APs; in cerebellar Purkinje cells, YC2.60 as well as YC-Nano15 is suitable for detecting CSs.
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Affiliation(s)
- Yoshiyuki Yamada
- Japan Science and Technology Agency, International Cooperative Research Project and Solution-Oriented Research for Science and Technology, Calcium Oscillation Project, Wako-shi Saitama, Japan
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167
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Remington SJ. Green fluorescent protein: a perspective. Protein Sci 2011; 20:1509-19. [PMID: 21714025 PMCID: PMC3190146 DOI: 10.1002/pro.684] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 06/20/2011] [Accepted: 06/21/2011] [Indexed: 11/07/2022]
Abstract
A brief personal perspective is provided for green fluorescent protein (GFP), covering the period 1994-2011. The topics discussed are primarily those in which my research group has made a contribution and include structure and function of the GFP polypeptide, the mechanism of fluorescence emission, excited state protein transfer, the design of ratiometric fluorescent protein biosensors and an overview of the fluorescent proteins derived from coral reef animals. Structure-function relationships in photoswitchable fluorescent proteins and nonfluorescent chromoproteins are also briefly covered.
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Affiliation(s)
- S James Remington
- Institute of Molecular Biology and Department of Physics, University of Oregon, Eugene, Oregon 97403-1229, USA.
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168
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Kantevari S, Buskila Y, Ellis-Davies GCR. Synthesis and characterization of cell-permeant 6-nitrodibenzofuranyl-caged IP3. Photochem Photobiol Sci 2011; 11:508-13. [PMID: 21879138 DOI: 10.1039/c1pp05155e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have synthesized in a 6-nitrodibenzofuranyl (NDBF) derivative of inositol-1,4,5-trisphosphate (IP(3)) for efficient two-photon uncaging in living cells. As its hexakis acetoxymethyl ester, this caged compound may be applied at low concentration to the extracellular milieu to load the intact astrocytes in acutely isolated brain slices from the mouse cortex. Two-photon irradiation of single astrocytes evoked intracellular calcium signals that required 10% of the energy dosage compared to nitroveratyl (NV)-IP(3). Since NDBF-IP(3) has a 5-fold higher quantum yield than NV-IP(3), these data imply that photolysis of the new NDBF caged compound mobilized intracellular calcium about twice as efficiently as the NV cage.
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Affiliation(s)
- Srinivas Kantevari
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA
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169
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Abstract
INTRODUCTIONDuring the past decades, many different fluorescent indicators have been developed for measuring intracellular ion concentrations. Of particular interest are fluorescent calcium indicators because of the fundamental role of Ca2+in various cellular processes such as contraction, secretion, and gene activation. For a quantitative understanding of the physiological roles of Ca2+, fluorescence signals measured with calcium indicators have to be converted to intracellular free calcium concentration ([Ca2+]i). Similarly, changes in [Ca2+]iand the underlying calcium fluxes need to be inferred from the corresponding fluorescence changes. This article describes the theoretical background and the various principal methods for the calibration of calcium imaging data.
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170
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Wyart C, Del Bene F. Let there be light: zebrafish neurobiology and the optogenetic revolution. Rev Neurosci 2011; 22:121-30. [PMID: 21615266 DOI: 10.1515/rns.2011.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Optogenetics has revolutionized the toolbox arsenal that neuroscientists now possess to investigate neuronal circuit function in intact and living animals. With a combination of light emitting 'sensors' and light activated 'actuators', we can monitor and control neuronal activity with minimal perturbation and unprecedented spatiotemporal resolution. Zebrafish neuronal circuits represent an ideal system to apply an optogenetic based analysis owing to its transparency, relatively small size and amenability to genetic manipulation. In this review, we describe some of the most recent advances in the development and applications of optogenetic sensors (i.e., genetically encoded calcium indicators and voltage sensors) and actuators (i.e., light activated ion channels and ion pumps). We focus mostly on the tools that have already been successfully applied in zebrafish and on those that show the greatest potential for the future. We also describe crucial technical aspects to implement optogenetics in zebrafish including strategies to drive a high level of transgene expression in defined neuronal populations, and recent optical advances that allow the precise spatiotemporal control of sample illumination.
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Affiliation(s)
- Claire Wyart
- Institut du Cerveau et de la Moelle epiniere, Centre de Recherche, CHU Pitié-Salpétrière, Paris, France.
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171
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Newman RH, Fosbrink MD, Zhang J. Genetically encodable fluorescent biosensors for tracking signaling dynamics in living cells. Chem Rev 2011; 111:3614-66. [PMID: 21456512 PMCID: PMC3092831 DOI: 10.1021/cr100002u] [Citation(s) in RCA: 260] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Robert H. Newman
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Matthew D. Fosbrink
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Jin Zhang
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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172
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Jaepel J, Blum R. Capturing ER calcium dynamics. Eur J Cell Biol 2011; 90:613-9. [PMID: 21561683 DOI: 10.1016/j.ejcb.2011.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 02/21/2011] [Accepted: 02/28/2011] [Indexed: 12/22/2022] Open
Abstract
The lumen of the endoplasmic reticulum (ER) contributes to the dynamics of Ca(2+) signaling by acting as a source or sink of signal Ca(2+). Despite its relevance for the understanding of the cell biology and pathophysiology of the luminal calcium store, the direct measurement of luminal Ca(2+) release and uptake is still critical when Ca(2+) homeostasis is analyzed in neural cells. For the analysis of Ca(2+)-dependent signaling, synthetic Ca(2+) indicators have become popular. The properties of these indicators allow only limited targeting to subcellular structures such as the ER. Recently, we introduced a new strategy for the targeting of synthetic Ca(2+) indicators to the lumen of the ER. The method, termed Targeted-Esterase-induced Dye loading (TED) is based on the targeted recombinant expression of a high carboxylesterase (CES) activity in the lumen of the ER, which is needed to trap synthetic indicators. The method combines the selectivity of protein targeting with the biochemical advantages of low-affinity synthetic Ca(2+) indicators. TED permits direct and non-disruptive measurement and imaging of Ca(2+)-store dynamics. Here, we summarize major topics in the cell biology of ER Ca(2+) signaling and discuss the perspectives of the TED method for the morphological and physiological analysis of temporal and spatial Ca(2+)-dynamics in neural cells.
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Affiliation(s)
- Juliane Jaepel
- Institute for Clinical Neurobiology, University of Würzburg, Würzburg, Germany
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173
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Abstract
Microscopes using non-linear excitation of chromophores with pulsed near-IR light can generate highly localized foci of molecules in the electronic singlet state that are concentrated in volumes of less than one femtoliter. The three-dimensional confinement of excitation arises from the simultaneous absorption of two IR photons of approximately half the energy required for linear excitation. Two-photon microscopy is especially useful for two types of interrogation of neural processes. First, uncaging of signaling molecules such as glutamate, as stimulation is so refined it can be used to mimic normal unitary synaptic levels. In addition, uncaging allows complete control of the timing and position of stimulation, so the two-photon light beam provides the chemical neuroscientist with an "optical conductor's baton" which can command synaptic activity at will. A second powerful feature of two-photon microscopy is that when used for fluorescence imaging it enables the visualization of cellular structure and function in living animals at depths far beyond that possible with normal confocal microscopes. In this review I provide a survey of the many important applications of two-photon microscopy in these two fields of neuroscience, and suggest some areas for future technical development.
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174
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Abstract
This protocol describes a method for efficient chemical synthesis of dinitroindolinyl derivatives of glutamate and γ-aminobutyric acid. These caged neurotransmitters are currently the most chemically and photochemically efficient probes for two-photon photolysis in living brain slices. The protocol only requires basic organic synthesis equipment, and no silica gel column chromatography or NMR spectroscopy is needed at any stage. HPLC is used to purify the caged transmitters at the end of the syntheses. Thus, the synthesis of dinitroindolinyl-caged neurotransmitters is within the scope of a modestly equipped chemistry laboratory.
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175
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Yamauchi JG, Nemecz Á, Nguyen QT, Muller A, Schroeder LF, Talley TT, Lindstrom J, Kleinfeld D, Taylor P. Characterizing ligand-gated ion channel receptors with genetically encoded Ca2++ sensors. PLoS One 2011; 6:e16519. [PMID: 21305050 PMCID: PMC3030600 DOI: 10.1371/journal.pone.0016519] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 12/21/2010] [Indexed: 11/23/2022] Open
Abstract
We present a cell based system and experimental approach to characterize agonist and antagonist selectivity for ligand-gated ion channels (LGIC) by developing sensor cells stably expressing a Ca2+ permeable LGIC and a genetically encoded Förster (or fluorescence) resonance energy transfer (FRET)-based calcium sensor. In particular, we describe separate lines with human α7 and human α4β2 nicotinic acetylcholine receptors, mouse 5-HT3A serotonin receptors and a chimera of human α7/mouse 5-HT3A receptors. Complete concentration-response curves for agonists and Schild plots of antagonists were generated from these sensors and the results validate known pharmacology of the receptors tested. Concentration-response relations can be generated from either the initial rate or maximal amplitudes of FRET-signal. Although assaying at a medium throughput level, this pharmacological fluorescence detection technique employs a clonal line for stability and has versatility for screening laboratory generated congeners as agonists or antagonists on multiple subtypes of ligand-gated ion channels. The clonal sensor lines are also compatible with in vivo usage to measure indirectly receptor activation by endogenous neurotransmitters.
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Affiliation(s)
- John G. Yamauchi
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California, United States of America
| | - Ákos Nemecz
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, United States of America
| | - Quoc Thang Nguyen
- Department of Physics, University of California San Diego, La Jolla, California, United States of America
| | - Arnaud Muller
- Department of Physics, University of California San Diego, La Jolla, California, United States of America
| | - Lee F. Schroeder
- Department of Physics, University of California San Diego, La Jolla, California, United States of America
| | - Todd T. Talley
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Jon Lindstrom
- Department of Neurosciences, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - David Kleinfeld
- Department of Physics, University of California San Diego, La Jolla, California, United States of America
| | - Palmer Taylor
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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176
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Fluorescent Genetically Encoded Calcium Indicators and Their In Vivo Application. FLUORESCENT PROTEINS II 2011. [DOI: 10.1007/4243_2011_29] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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177
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Jia H, Rochefort NL, Chen X, Konnerth A. In vivo two-photon imaging of sensory-evoked dendritic calcium signals in cortical neurons. Nat Protoc 2010; 6:28-35. [DOI: 10.1038/nprot.2010.169] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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178
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Heider B, Nathanson JL, Isacoff EY, Callaway EM, Siegel RM. Two-photon imaging of calcium in virally transfected striate cortical neurons of behaving monkey. PLoS One 2010; 5:e13829. [PMID: 21079806 PMCID: PMC2973959 DOI: 10.1371/journal.pone.0013829] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 10/11/2010] [Indexed: 11/18/2022] Open
Abstract
Two-photon scanning microscopy has advanced our understanding of neural signaling in non-mammalian species and mammals. Various developments are needed to perform two-photon scanning microscopy over prolonged periods in non-human primates performing a behavioral task. In striate cortex in two macaque monkeys, cortical neurons were transfected with a genetically encoded fluorescent calcium sensor, memTNXL, using AAV1 as a viral vector. By constructing an extremely rigid and stable apparatus holding both the two-photon scanning microscope and the monkey's head, single neurons were imaged at high magnification for prolonged periods with minimal motion artifacts for up to ten months. Structural images of single neurons were obtained at high magnification. Changes in calcium during visual stimulation were measured as the monkeys performed a fixation task. Overall, functional responses and orientation tuning curves were obtained in 18.8% of the 234 labeled and imaged neurons. This demonstrated that the two-photon scanning microscopy can be successfully obtained in behaving primates.
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Affiliation(s)
- Barbara Heider
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey, United States of America
| | - Jason L. Nathanson
- System Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Ehud Y. Isacoff
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Edward M. Callaway
- System Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Ralph M. Siegel
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey, United States of America
- * E-mail:
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179
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Lacar B, Young SZ, Platel JC, Bordey A. Imaging and recording subventricular zone progenitor cells in live tissue of postnatal mice. Front Neurosci 2010; 4:43. [PMID: 20700392 PMCID: PMC2918349 DOI: 10.3389/fnins.2010.00043] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Accepted: 06/08/2010] [Indexed: 01/30/2023] Open
Abstract
The subventricular zone (SVZ) is one of two regions where neurogenesis persists in the postnatal brain. The SVZ, located along the lateral ventricle, is the largest neurogenic zone in the brain that contains multiple cell populations including astrocyte-like cells and neuroblasts. Neuroblasts migrate in chains to the olfactory bulb where they differentiate into interneurons. Here, we discuss the experimental approaches to record the electrophysiology of these cells and image their migration and calcium activity in acute slices. Although these techniques were in place for studying glial cells and neurons in mature networks, the SVZ raises new challenges due to the unique properties of SVZ cells, the cellular diversity, and the architecture of the region. We emphasize different methods, such as the use of transgenic mice and in vivo electroporation that permit identification of the different SVZ cell populations for patch clamp recording or imaging. Electroporation also permits genetic labeling of cells using fluorescent reporter mice and modification of the system using either RNA interference technology or floxed mice. In this review, we aim to provide conceptual and technical details of the approaches to perform electrophysiological and imaging studies of SVZ cells.
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Affiliation(s)
- Benjamin Lacar
- Department of Neurosurgery, Yale University School of MedicineNew Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale University School of MedicineNew Haven, CT, USA
| | - Stephanie Z. Young
- Department of Neurosurgery, Yale University School of MedicineNew Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale University School of MedicineNew Haven, CT, USA
| | - Jean-Claude Platel
- Department of Neurosurgery, Yale University School of MedicineNew Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale University School of MedicineNew Haven, CT, USA
| | - Angélique Bordey
- Department of Neurosurgery, Yale University School of MedicineNew Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale University School of MedicineNew Haven, CT, USA
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180
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Hernández-García D, Wood CD, Castro-Obregón S, Covarrubias L. Reactive oxygen species: A radical role in development? Free Radic Biol Med 2010; 49:130-43. [PMID: 20353819 DOI: 10.1016/j.freeradbiomed.2010.03.020] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 03/20/2010] [Accepted: 03/23/2010] [Indexed: 02/07/2023]
Abstract
Reactive oxygen species (ROS), mostly derived from mitochondrial activity, can damage various macromolecules and consequently cause cell death. This ROS activity has been characterized in vitro, and correlative evidence suggests a role in various pathological conditions. In addition to this passive ROS activity, ROS also participate in cell signaling processes, though the relevance of this function in vivo is poorly understood. Throughout development, elevated cell activity is probably accompanied by highly active metabolism and, consequently, the production of large amounts of ROS. To allow proper development, cells must protect themselves from these potentially damaging ROS. However, to what degree ROS could participate as signaling molecules controlling fundamental and developmentally relevant cellular processes such as proliferation, differentiation, and death is an open question. Here we discuss why available data do not yet provide conclusive evidence on the role of ROS in development, and we review recent methods to detect ROS in vivo and genetic strategies that can be exploited specifically to resolve these uncertainties.
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Affiliation(s)
- David Hernández-García
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
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181
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182
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Lütcke H, Murayama M, Hahn T, Margolis DJ, Astori S, Zum Alten Borgloh SM, Göbel W, Yang Y, Tang W, Kügler S, Sprengel R, Nagai T, Miyawaki A, Larkum ME, Helmchen F, Hasan MT. Optical recording of neuronal activity with a genetically-encoded calcium indicator in anesthetized and freely moving mice. Front Neural Circuits 2010; 4:9. [PMID: 20461230 PMCID: PMC2866455 DOI: 10.3389/fncir.2010.00009] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 03/17/2010] [Indexed: 12/29/2022] Open
Abstract
Fluorescent calcium (Ca2+) indicator proteins (FCIPs) are promising tools for functional imaging of cellular activity in living animals. However, they have still not reached their full potential for in vivo imaging of neuronal activity due to limitations in expression levels, dynamic range, and sensitivity for reporting action potentials. Here, we report that viral expression of the ratiometric Ca2+ sensor yellow cameleon 3.60 (YC3.60) in pyramidal neurons of mouse barrel cortex enables in vivo measurement of neuronal activity with high dynamic range and sensitivity across multiple spatial scales. By combining juxtacellular recordings and two-photon imaging in vitro and in vivo, we demonstrate that YC3.60 can resolve single action potential (AP)-evoked Ca2+ transients and reliably reports bursts of APs with negligible saturation. Spontaneous and whisker-evoked Ca2+ transients were detected in individual apical dendrites and somata as well as in local neuronal populations. Moreover, bulk measurements using wide-field imaging or fiber-optics revealed sensory-evoked YC3.60 signals in large areas of the barrel field. Fiber-optic recordings in particular enabled measurements in awake, freely moving mice and revealed complex Ca2+ dynamics, possibly reflecting different behavior-related brain states. Viral expression of YC3.60 – in combination with various optical techniques – thus opens a multitude of opportunities for functional studies of the neural basis of animal behavior, from dendrites to the levels of local and large-scale neuronal populations.
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Affiliation(s)
- Henry Lütcke
- Department of Neurophysiology, Brain Research Institute, University of Zurich Zurich, Switzerland
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183
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Naumann EA, Kampff AR, Prober DA, Schier AF, Engert F. Monitoring neural activity with bioluminescence during natural behavior. Nat Neurosci 2010; 13:513-20. [PMID: 20305645 PMCID: PMC2846983 DOI: 10.1038/nn.2518] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 02/22/2010] [Indexed: 02/07/2023]
Abstract
Existing techniques for monitoring neural activity in awake, freely behaving vertebrates are invasive and difficult to target to genetically identified neurons. We used bioluminescence to non-invasively monitor the activity of genetically specified neurons in freely behaving zebrafish. Transgenic fish with the Ca(2+)-sensitive photoprotein green fluorescent protein (GFP)-Aequorin in most neurons generated large and fast bioluminescent signals that were related to neural activity, neuroluminescence, which could be recorded continuously for many days. To test the limits of this technique, we specifically targeted GFP-Aequorin to the hypocretin-positive neurons of the hypothalamus. We found that neuroluminescence generated by this group of approximately 20 neurons was associated with periods of increased locomotor activity and identified two classes of neural activity corresponding to distinct swim latencies. Our neuroluminescence assay can report, with high temporal resolution and sensitivity, the activity of small subsets of neurons during unrestrained behavior.
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Affiliation(s)
- Eva A Naumann
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
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184
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Drobac E, Tricoire L, Chaffotte AF, Guiot E, Lambolez B. Calcium imaging in single neurons from brain slices using bioluminescent reporters. J Neurosci Res 2010; 88:695-711. [PMID: 19798746 DOI: 10.1002/jnr.22249] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Responses of three bioluminescent Ca(2+) sensors were studied in vitro and in neurons from brain slices. These sensors consisted of tandem fusions of green fluorescent protein (GFP) with the photoproteins aequorin, obelin, or a mutant aequorin with high Ca(2+) sensitivity. Kinetics of GFP-obelin responses to a saturating Ca(2+) concentration were faster than those of GFP-aequorin at all Mg(2+) concentrations tested, whereas GFP-mutant aequorin responses were the slowest. GFP-photoproteins were efficiently expressed in pyramidal neurons following overnight incubation of acute neocortical slices with recombinant Sindbis viruses. Expression of GFP-photoproteins did not result in conspicuous modification of morphological or electrophysiological properties of layer V pyramidal cells. The three sensors allowed the detection of Ca(2+) transients associated with action potential discharge in single layer V pyramidal neurons. In these neurons, depolarizing steps of increasing amplitude elicited action potential discharge of increasing frequency. Bioluminescent responses of the three sensors were similar in several respects: detection thresholds, an exponential increase with stimulus intensity, photoprotein consumptions, and kinetic properties. These responses, which were markedly slower than kinetics measured in vitro, increased linearly during the action potential discharge and decayed exponentially at the end of the discharge. Onset slopes increased with stimulus intensity, whereas decay kinetics remained constant. Dendritic light emission contributed to whole-field responses, but the spatial resolution of bioluminescence imaging was limited to the soma and proximal apical dendrite. Nonetheless, the high signal-to-background ratio of GFP-photoproteins allowed the detection of Ca(2+) transients associated with 5 action potentials in single neurons upon whole-field bioluminescence recordings.
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Affiliation(s)
- Estelle Drobac
- Université Pierre et Marie Curie-Paris 6, Neurobiologie des Processus Adaptatifs, CNRS UMR 7102, Paris, France
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185
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Control of intracellular calcium signaling as a neuroprotective strategy. Molecules 2010; 15:1168-95. [PMID: 20335972 PMCID: PMC2847496 DOI: 10.3390/molecules15031168] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Revised: 02/05/2010] [Accepted: 03/02/2010] [Indexed: 12/13/2022] Open
Abstract
Both acute and chronic degenerative diseases of the nervous system reduce the viability and function of neurons through changes in intracellular calcium signaling. In particular, pathological increases in the intracellular calcium concentration promote such pathogenesis. Disease involvement of numerous regulators of intracellular calcium signaling located on the plasma membrane and intracellular organelles has been documented. Diverse groups of chemical compounds targeting ion channels, G-protein coupled receptors, pumps and enzymes have been identified as potential neuroprotectants. The present review summarizes the discovery, mechanisms and biological activity of neuroprotective molecules targeting proteins that control intracellular calcium signaling to preserve or restore structure and function of the nervous system. Disease relevance, clinical applications and new technologies for the identification of such molecules are being discussed.
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186
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Design strategies of fluorescent biosensors based on biological macromolecular receptors. SENSORS 2010; 10:1355-76. [PMID: 22205872 PMCID: PMC3244018 DOI: 10.3390/s100201355] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 01/29/2010] [Accepted: 02/04/2010] [Indexed: 11/17/2022]
Abstract
Fluorescent biosensors to detect the bona fide events of biologically important molecules in living cells are increasingly demanded in the field of molecular cell biology. Recent advances in the development of fluorescent biosensors have made an outstanding contribution to elucidating not only the roles of individual biomolecules, but also the dynamic intracellular relationships between these molecules. However, rational design strategies of fluorescent biosensors are not as mature as they look. An insatiable request for the establishment of a more universal and versatile strategy continues to provide an attractive alternative, so-called modular strategy, which permits facile preparation of biosensors with tailored characteristics by a simple combination of a receptor and a signal transducer. This review describes an overview of the progress in design strategies of fluorescent biosensors, such as auto-fluorescent protein-based biosensors, protein-based biosensors covalently modified with synthetic fluorophores, and signaling aptamers, and highlights the insight into how a given receptor is converted to a fluorescent biosensor. Furthermore, we will demonstrate a significance of the modular strategy for the sensor design.
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187
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Wang H, Nakata E, Hamachi I. Recent progress in strategies for the creation of protein-based fluorescent biosensors. Chembiochem 2010; 10:2560-77. [PMID: 19693761 DOI: 10.1002/cbic.200900249] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The creation of novel bioanalytical tools for the detection and monitoring of a range of important target substances and biological events in vivo and in vitro is a great challenge in chemical biology and biotechnology. Protein-based fluorescent biosensors--integrated devices that convert a molecular-recognition event to a fluorescent signal--have recently emerged as a powerful tool. As the recognition units various proteins that can specifically recognize and bind a variety of molecules of biological significance with high affinity are employed. For the transducer, fluorescent proteins, such as green fluorescent protein (GFP) or synthetic fluorophores, are mostly adopted. Recent progress in protein engineering and organic synthesis allows us to manipulate proteins genetically and/or chemically, and a library of such protein scaffolds has been significantly expanded by genome projects. In this review, we briefly describe the recent progress of protein-based fluorescent biosensors on the basis of their platform and construction strategy, which are primarily divided into the genetically encoded fluorescent biosensors and chemically constructed biosensors.
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Affiliation(s)
- Hangxiang Wang
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
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188
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Nakazono M, Jinguji A, Nanbu S, Kuwano R, Zheng Z, Saita K, Oshikawa Y, Mikuni Y, Murakami T, Zhao Y, Sasaki S, Zaitsu K. Fluorescence and chemiluminescence properties of indolylmaleimides: experimental and theoretical studies. Phys Chem Chem Phys 2010; 12:9783-93. [DOI: 10.1039/c003021j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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189
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Resch-Genger U, Grabolle M, Nitschke R, Nann T. Nanocrystals and Nanoparticles Versus Molecular Fluorescent Labels as Reporters for Bioanalysis and the Life Sciences: A Critical Comparison. ADVANCED FLUORESCENCE REPORTERS IN CHEMISTRY AND BIOLOGY II 2010. [DOI: 10.1007/978-3-642-04701-5_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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190
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191
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Abstract
Small, fluorescent, calcium-sensing molecules have been enormously useful in mapping intracellular calcium signals in time and space, as chapters in this volume attest. Despite their widespread adoption and utility, they suffer some disadvantages. Genetically encoded calcium sensors that can be expressed inside cells by transfection or transgenesis are desirable. The last 10 years have been marked by a rapid evolution in the laboratory of genetically encoded calcium sensors both figuratively and literally, resulting in 11 distinct configurations of fluorescent proteins and their attendant calcium sensor modules. Here, the design logic and performance of this abundant collection of sensors and their in vitro and in vivo use and performance are described. Genetically encoded calcium sensors have proved valuable in the measurement of calcium concentration in cellular organelles, for the most part in single cells in vitro. Their success as quantitative calcium sensors in tissues in vitro and in vivo is qualified, but they have proved valuable in imaging the pattern of calcium signals within tissues in whole animals. Some branches of the calcium sensor evolutionary tree continue to evolve rapidly and the steady progress in optimizing sensor parameters leads to the certain hope that these drawbacks will eventually be overcome by further genetic engineering.
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Affiliation(s)
- Michael Whitaker
- Institute of Cell and Molecular Biosciences Medical School, Newcastle University, Framlington Place Newcastle upon Tyne, United Kingdom
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192
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Wilms CD, Häusser M. Lighting up neural networks using a new generation of genetically encoded calcium sensors. Nat Methods 2009; 6:871-2. [PMID: 19935839 DOI: 10.1038/nmeth1209-871] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Two improved genetically encoded calcium indicators-based on structure-guided sensor design or on precise subcellular targeting to presynaptic boutons-allow single spikes to be detected in genetically defined populations of neurons and synapses in vivo.
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Affiliation(s)
- Christian D Wilms
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, UK
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193
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Abstract
Electrophysiology, the 'gold standard' for investigating neuronal signalling, is being challenged by a new generation of optical probes. Together with new forms of microscopy, these probes allow us to measure and control neuronal signals with spatial resolution and genetic specificity that already greatly surpass those of electrophysiology. We predict that the photon will progressively replace the electron for probing neuronal function, particularly for targeted stimulation and silencing of neuronal populations. Although electrophysiological characterization of channels, cells and neural circuits will remain necessary, new combinations of electrophysiology and imaging should lead to transformational discoveries in neuroscience.
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194
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Ibraheem A, Campbell RE. Designs and applications of fluorescent protein-based biosensors. Curr Opin Chem Biol 2009; 14:30-6. [PMID: 19913453 DOI: 10.1016/j.cbpa.2009.09.033] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 09/23/2009] [Indexed: 10/20/2022]
Abstract
Genetically encoded biosensors allow the noninvasive imaging of specific biochemical or biorecognition processes with the preservation of subcellular spatial and temporal information. Aequorea green fluorescent protein (FP) and its engineered variants are a critical component of genetically encoded biosensors, as they serve to provide a 'read-out' of the biorecognition event under investigation. The family of FP-based biosensors includes a diverse array of designs that utilize various photophysical characteristics of the FPs. In this review, we will discuss these designs and their read-outs through reviewing some of the recent works in this area.
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Affiliation(s)
- Andreas Ibraheem
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada T6G2G2
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195
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Imaging neural activity in worms, flies and mice with improved GCaMP calcium indicators. Nat Methods 2009; 6:875-81. [PMID: 19898485 PMCID: PMC2858873 DOI: 10.1038/nmeth.1398] [Citation(s) in RCA: 1451] [Impact Index Per Article: 96.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 10/09/2009] [Indexed: 12/11/2022]
Abstract
Genetically encoded calcium indicators (GECIs) can be used to image activity in defined neuronal populations. However, current GECIs produce inferior signals compared to synthetic indicators and recording electrodes, precluding detection of low firing rates. We developed a single-wavelength GECI based on GCaMP2 (GCaMP3), with increased baseline fluorescence (3x), dynamic range (3x), and higher affinity for calcium (1.3x). GCaMP3 fluorescence changes triggered by single action potentials were detected in pyramidal cell dendrites, with signal-to-noise ratio and photostability significantly better than GCaMP2, D3cpVenus, and TN-XXL. In Caenorhabditis elegans chemosensory neurons and the Drosophila melanogaster antennal lobe, sensory stimulation-evoked fluorescence responses were significantly enhanced with the new indicator (4–6x). In somatosensory and motor cortical neurons in the intact mouse, GCaMP3 detected calcium transients with amplitudes linearly dependent on action potential number. Long-term imaging in the motor cortex of behaving mice revealed large fluorescence changes in imaged neurons over months.
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196
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Optical probing of neuronal ensemble activity. Curr Opin Neurobiol 2009; 19:520-9. [PMID: 19854041 DOI: 10.1016/j.conb.2009.09.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 09/15/2009] [Indexed: 11/24/2022]
Abstract
Neural computations are implemented in densely interconnected networks of excitable neurons as temporal sequences of coactive neuronal ensembles. Ensemble activity is produced by the interaction of external stimuli with internal states but has been difficult to directly study in the past. Currently, high-resolution optical imaging techniques are emerging as powerful tools to investigate neuronal ensembles in living animals and to characterize their spatiotemporal properties. Here we review recent advances of two-photon calcium imaging and highlight ongoing technical improvements as well as emerging applications. Significant progress has been made in the extent and speed of imaging and in the adaptation of imaging techniques to awake animals. These advances facilitate studies of the functional organization of local neural networks, their experience-dependent reconfiguration, and their functional impairment in diseases. Optical probing of neuronal ensemble dynamics in vivo thus promises to reveal fundamental principles of neural circuit function and dysfunction.
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197
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198
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Ben-Yakar A, Chronis N, Lu H. Microfluidics for the analysis of behavior, nerve regeneration, and neural cell biology in C. elegans. Curr Opin Neurobiol 2009; 19:561-7. [PMID: 19896831 PMCID: PMC3107678 DOI: 10.1016/j.conb.2009.10.010] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Accepted: 10/02/2009] [Indexed: 01/28/2023]
Abstract
The nematode Caenorhabditis elegans is a widely adopted model organism for studying various neurobiological processes at the molecular and cellular level in vivo. With a small, flexible, and continuously moving body, the manipulation of C. elegans becomes a challenging task. In this review, we highlight recent advances in microfluidic technologies for the manipulation of C. elegans. These new family of microfluidic chips are capable of handling single or populations of worms in a high-throughput fashion and accurately controlling their microenvironment. So far, they have been successfully used to study neural circuits and behavior, to perform large-scale phetotyping and morphology-based screens as well as to understand axon regeneration after injury. We envision that microfluidic chips can further be used to study different aspects of the C. elegans nervous system, extending from fundamental understanding of behavioral dynamics to more complicated biological processes such as neural aging and learning and memory.
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Affiliation(s)
- Adela Ben-Yakar
- Department of Mechanical Engineering, University of Texas at Austin, 204 E. Dean Keeton Street, Austin, TX 78705, USA
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199
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Frommer WB, Davidson MW, Campbell RE. Genetically encoded biosensors based on engineered fluorescent proteins. Chem Soc Rev 2009; 38:2833-41. [PMID: 19771330 DOI: 10.1039/b907749a] [Citation(s) in RCA: 236] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorescent proteins have revolutionized cell biology by allowing researchers to non-invasively peer into the inner workings of cells and organisms. While the most common applications of fluorescent proteins are to image expression, localization, and dynamics of protein chimeras, there is a growing interest in using fluorescent proteins to create biosensors for minimally invasive imaging of concentrations of ions and small molecules, the activity of enzymes, and changes in the conformation of proteins in living cells. This tutorial review provides an overview of the progress made in the development of fluorescent protein-based biosensors to date.
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Affiliation(s)
- Wolf B Frommer
- Carnegie Institution for Science, 260 Panama St., Stanford, CA 94305, USA.
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Akemann W, Middleton SJ, Knöpfel T. Optical imaging as a link between cellular neurophysiology and circuit modeling. Front Cell Neurosci 2009; 3:5. [PMID: 19649169 PMCID: PMC2718781 DOI: 10.3389/neuro.03.005.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 06/30/2009] [Indexed: 11/16/2022] Open
Abstract
The relatively simple and highly modular circuitry of the cerebellum raised expectations decades ago that a realistic computational model of cerebellar circuit operations would be feasible, and prove insightful for unraveling cerebellar information processing. To this end, the biophysical properties of most cerebellar cell types and their synaptic connections have been well characterized and integrated into realistic single cell models. Furthermore, large scale models of cerebellar circuits that extrapolate from single cell properties to circuit dynamics have been constructed. While the development of single cell models have been constrained by microelectrode recordings, guidance and validation as these models are scaled up to study network interactions requires an experimental methodology capable of monitoring cerebellar dynamics at the population level. Here we review the potential of optical imaging techniques to serve this purpose.
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Affiliation(s)
- Walther Akemann
- Laboratory for Neuronal Circuit Dynamics, RIKEN Brain Science Institute Wako, Japan
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