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Maltan L, Najjar H, Tiffner A, Derler I. Deciphering Molecular Mechanisms and Intervening in Physiological and Pathophysiological Processes of Ca 2+ Signaling Mechanisms Using Optogenetic Tools. Cells 2021; 10:3340. [PMID: 34943850 PMCID: PMC8699489 DOI: 10.3390/cells10123340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/17/2021] [Accepted: 11/22/2021] [Indexed: 11/16/2022] Open
Abstract
Calcium ion channels are involved in numerous biological functions such as lymphocyte activation, muscle contraction, neurotransmission, excitation, hormone secretion, gene expression, cell migration, memory, and aging. Therefore, their dysfunction can lead to a wide range of cellular abnormalities and, subsequently, to diseases. To date various conventional techniques have provided valuable insights into the roles of Ca2+ signaling. However, their limited spatiotemporal resolution and lack of reversibility pose significant obstacles in the detailed understanding of the structure-function relationship of ion channels. These drawbacks could be partially overcome by the use of optogenetics, which allows for the remote and well-defined manipulation of Ca2+-signaling. Here, we review the various optogenetic tools that have been used to achieve precise control over different Ca2+-permeable ion channels and receptors and associated downstream signaling cascades. We highlight the achievements of optogenetics as well as the still-open questions regarding the resolution of ion channel working mechanisms. In addition, we summarize the successes of optogenetics in manipulating many Ca2+-dependent biological processes both in vitro and in vivo. In summary, optogenetics has significantly advanced our understanding of Ca2+ signaling proteins and the used tools provide an essential basis for potential future therapeutic application.
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Affiliation(s)
| | | | | | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria; (L.M.); (H.N.); (A.T.)
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Smaga LP, Pino NW, Ibarra GE, Krishnamurthy V, Chan J. A Photoactivatable Formaldehyde Donor with Fluorescence Monitoring Reveals Threshold To Arrest Cell Migration. J Am Chem Soc 2020; 142:680-684. [PMID: 31898899 DOI: 10.1021/jacs.9b11899] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Controlled light-mediated delivery of biological analytes can enable the investigation of highly reactivity molecules within living systems. As many biological effects are concentration dependent, it is critical to determine the location, time, and quantity of analyte donation. In this work, we have developed the first photoactivatable donor for formaldehyde (FA). Our optimized photoactivatable donor, photoFAD-3, is equipped with a fluorescence readout that enables monitoring of FA release with a concomitant 139-fold fluorescence enhancement. Tuning of photostability and cellular retention enabled quantification of intracellular FA release through cell lysate calibration. Application of photoFAD-3 uncovered the concentration range necessary for arresting wound healing in live cells. This marks the first report where a photoactivatable donor for any analyte has been used to quantify intracellular release.
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Affiliation(s)
- Lukas P Smaga
- Department of Chemistry and Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Nicholas W Pino
- Department of Chemistry and Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Gabriela E Ibarra
- Department of Chemistry and Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Vishnu Krishnamurthy
- Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Jefferson Chan
- Department of Chemistry and Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
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3
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Ducrot A, Tron A, Bofinger R, Sanz Beguer I, Pozzo JL, McClenaghan ND. Photoreversible stretching of a BAPTA chelator marshalling Ca 2+-binding in aqueous media. Beilstein J Org Chem 2019; 15:2801-2811. [PMID: 31807215 PMCID: PMC6880838 DOI: 10.3762/bjoc.15.273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 11/08/2019] [Indexed: 01/04/2023] Open
Abstract
Free calcium ion concentration is known to govern numerous biological processes and indeed calcium acts as an important biological secondary messenger for muscle contraction, neurotransmitter release, ion-channel gating, and exocytosis. As such, the development of molecules with the ability to instantaneously increase or diminish free calcium concentrations potentially allows greater control over certain biological functions. In order to permit remote regulation of Ca2+, a selective BAPTA-type synthetic receptor / host was integrated with a photoswitchable azobenzene motif, which upon photoirradiation would enhance (or diminish) the capacity to bind calcium upon acting on the conformation of the adjacent binding site, rendering it a stronger or weaker binder. Photoswitching was studied in pseudo-physiological conditions (pH 7.2, [KCl] = 100 mM) and dissociation constants for azobenzene cis- and trans-isomers have been determined (0.230 μM and 0.102 μM, respectively). Reversible photoliberation/uptake leading to a variation of free calcium concentration in solution was detected using a fluorescent Ca2+ chemosensor.
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Affiliation(s)
- Aurélien Ducrot
- Institut des Sciences Moléculaires, CNRS UMR 5255, Univ. Bordeaux, 351 cours de la Libération, 33405 Talence, France
| | - Arnaud Tron
- Institut des Sciences Moléculaires, CNRS UMR 5255, Univ. Bordeaux, 351 cours de la Libération, 33405 Talence, France
| | - Robin Bofinger
- Institut des Sciences Moléculaires, CNRS UMR 5255, Univ. Bordeaux, 351 cours de la Libération, 33405 Talence, France
| | - Ingrid Sanz Beguer
- Institut des Sciences Moléculaires, CNRS UMR 5255, Univ. Bordeaux, 351 cours de la Libération, 33405 Talence, France
| | - Jean-Luc Pozzo
- Institut des Sciences Moléculaires, CNRS UMR 5255, Univ. Bordeaux, 351 cours de la Libération, 33405 Talence, France
| | - Nathan D McClenaghan
- Institut des Sciences Moléculaires, CNRS UMR 5255, Univ. Bordeaux, 351 cours de la Libération, 33405 Talence, France
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Light-triggered release of photocaged therapeutics - Where are we now? J Control Release 2019; 298:154-176. [PMID: 30742854 DOI: 10.1016/j.jconrel.2019.02.006] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 02/04/2019] [Accepted: 02/06/2019] [Indexed: 01/02/2023]
Abstract
The current available therapeutics face several challenges such as the development of ideal drug delivery systems towards the goal of personalized treatments for patients benefit. The application of light as an exogenous activation mechanism has shown promising outcomes, owning to the spatiotemporal confinement of the treatment in the vicinity of the diseased tissue, which offers many intriguing possibilities. Engineering therapeutics with light responsive moieties have been explored to enhance the bioavailability, and drug efficacy either in vitro or in vivo. The tailor-made character turns the so-called photocaged compounds highly desirable to reduce the side effects of drugs and, therefore, have received wide research attention. Herein, we seek to highlight the potential of photocaged compounds to obtain a clear understanding of the mechanisms behind its use in therapeutic delivery. A deep overview on the progress achieved in the design, fabrication as well as current and possible future applications in therapeutics of photocaged compounds is provided, so that novel formulations for biomedical field can be designed.
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Asano T, Igarashi H, Ishizuka T, Yawo H. Organelle Optogenetics: Direct Manipulation of Intracellular Ca 2+ Dynamics by Light. Front Neurosci 2018; 12:561. [PMID: 30174581 PMCID: PMC6107701 DOI: 10.3389/fnins.2018.00561] [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: 02/27/2018] [Accepted: 07/25/2018] [Indexed: 12/20/2022] Open
Abstract
As one of the ubiquitous second messengers, the intracellular Ca2+, has been revealed to be a pivotal regulator of various cellular functions. Two major sources are involved in the initiation of Ca2+-dependent signals: influx from the extracellular space and release from the intracellular Ca2+ stores such as the endoplasmic/sarcoplasmic reticulum (ER/SR). To manipulate the Ca2+ release from the stores under high spatiotemporal precision, we established a new method termed “organelle optogenetics.” That is, one of the light-sensitive cation channels (channelrhodopsin-green receiver, ChRGR), which is Ca2+-permeable, was specifically targeted to the ER/SR. The expression specificity as well as the functional operation of the ER/SR-targeted ChRGR (ChRGRER) was evaluated using mouse skeletal myoblasts (C2C12): (1) the ChRGRER co-localized with the ER-marker KDEL; (2) no membrane current was generated by light under whole-cell clamp of cells expressing ChRGRER; (3) an increase of fluorometric Ca2+ was evoked by the optical stimulation (OS) in the cells expressing ChRGRER in a manner independent on the extracellular Ca2+ concentration ([Ca2+]o); (4) the ΔF/F0 was sensitive to the inhibitor of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and (5) the store-operated Ca2+ entry (SOCE) was induced by the OS in the ChRGRER-expressing cells. Our organelle optogenetics effectively manipulated the ER/SR to release Ca2+ from intracellular stores. The use of organelle optogenetics would reveal the neuroscientific significance of intracellular Ca2+ dynamics under spatiotemporal precision.
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Affiliation(s)
- Toshifumi Asano
- Department of Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroyuki Igarashi
- Department of Physiology and Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Toru Ishizuka
- Department of Developmental Biology and Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Hiromu Yawo
- Department of Physiology and Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan.,Department of Developmental Biology and Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan
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Heymann RR, Thum MD, Hardee AL, Falvey DE. Visible light initiated release of calcium ions through photochemical electron transfer reactions. Photochem Photobiol Sci 2018; 16:1003-1008. [PMID: 28497836 DOI: 10.1039/c6pp00469e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Photolysis of anthraquinone or flavin photosensitizers in the presence of calcium EDTA complexes results in decomposition of the EDTA complex, releasing free Ca2+. In the case of the flavin sensitizers, it is shown that millimolar concentrations of Ca2+ can be released using visible light (>440 nm) and with quantum yields as high as 0.31. The utility of this system is further demonstrated by in situ photogelation of an alginate solution.
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Affiliation(s)
- Romina R Heymann
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA.
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Ma G, Wen S, He L, Huang Y, Wang Y, Zhou Y. Optogenetic toolkit for precise control of calcium signaling. Cell Calcium 2017; 64:36-46. [PMID: 28104276 PMCID: PMC5457325 DOI: 10.1016/j.ceca.2017.01.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 12/19/2022]
Abstract
Calcium acts as a second messenger to regulate a myriad of cell functions, ranging from short-term muscle contraction and cell motility to long-term changes in gene expression and metabolism. To study the impact of Ca2+-modulated 'ON' and 'OFF' reactions in mammalian cells, pharmacological tools and 'caged' compounds are commonly used under various experimental conditions. The use of these reagents for precise control of Ca2+ signals, nonetheless, is impeded by lack of reversibility and specificity. The recently developed optogenetic tools, particularly those built upon engineered Ca2+ release-activated Ca2+ (CRAC) channels, provide exciting opportunities to remotely and non-invasively modulate Ca2+ signaling due to their superior spatiotemporal resolution and rapid reversibility. In this review, we briefly summarize the latest advances in the development of optogenetic tools (collectively termed as 'genetically encoded Ca2+ actuators', or GECAs) that are tailored for the interrogation of Ca2+ signaling, as well as their applications in remote neuromodulation and optogenetic immunomodulation. Our goal is to provide a general guide to choosing appropriate GECAs for optical control of Ca2+ signaling in cellulo, and in parallel, to stimulate further thoughts on evolving non-opsin-based optogenetics into a fully fledged technology for the study of Ca2+-dependent activities in vivo.
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Affiliation(s)
- Guolin Ma
- Center for Translational Cancer Research, Institute of Biosciences and Technology Texas A&M University, Houston, TX 77030, USA
| | - Shufan Wen
- Center for Translational Cancer Research, Institute of Biosciences and Technology Texas A&M University, Houston, TX 77030, USA
| | - Lian He
- Center for Translational Cancer Research, Institute of Biosciences and Technology Texas A&M University, Houston, TX 77030, USA
| | - Yun Huang
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA; Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University, Bryan, TX 77807, USA
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
| | - Yubin Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology Texas A&M University, Houston, TX 77030, USA; Department of Medical Physiology, College of Medicine Texas A&M University, Temple, TX 76504, USA, USA.
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Lavie-Cambot A, Tron A, Ducrot A, Castet F, Kauffmann B, Beauté L, Allouchi H, Pozzo JL, Bonnet CS, McClenaghan ND. Synthetic water soluble di-/tritopic molecular receptors exhibiting Ca 2+/Mg 2+ exchange. Org Biomol Chem 2017; 15:4367-4374. [PMID: 28474718 DOI: 10.1039/c6ob02732f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Structural integration of two synthetic water soluble receptors for Ca2+ and Mg2+, namely 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) and o-aminophenol-N,N,O-triacetic acid (APTRA), respectively, gave novel di- and tritopic ionophores (1 and 2). As Mg2+ and Ca2+ cannot be simultaneously complexed by the receptors, allosteric control of complexation results. Potentiometric measurements established stepwise protonation constants and showed high affinity for Ca2+ (log K = 6.08 and 8.70 for 1 and 2, respectively) and an excellent selectivity over Mg2+ (log K = 3.70 and 5.60 for 1 and 2, respectively), which is compatible with magnesium-calcium ion exchange. While ion-exchange of a single Mg2+ for a single Ca2+ is possible in both 1 and 2, the simultaneous binding of two Mg2+ by 2 appears prohibitive for replacement of these two ions by a single Ca2+. Ion-binding and exchange was further rationalized by DFT calculations.
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Affiliation(s)
- Aurélie Lavie-Cambot
- Institut des Sciences Moléculaires, University of Bordeaux/CNRS, UMR 5255, F-33400 Talence, France.
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9
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Sutton MV, McKinley M, Kulasekharan R, Popik VV. Photo-cleavable analog of BAPTA for the fast and efficient release of Ca 2. Chem Commun (Camb) 2017; 53:5598-5601. [PMID: 28393957 PMCID: PMC6015727 DOI: 10.1039/c7cc02056b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new photocleavable analog of BAPTA chelating ligand has a high affinity towards Ca2+ ions (K = 2.5 × 106 M-1). The use of photolabile 3-(hydroxymethyl)-2-naphthol core in the design of photo-BAPTA allows for the efficient (Φ = 0. 63) and very fast (τ < 12 μs) release of Ca2+ ions upon 300 or 350 nm irradiation.
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Affiliation(s)
- Mariia V Sutton
- Department of Chemistry, University of Georgia, Athens, GA 30677, USA.
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10
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Agarwal HK, Janicek R, Chi SH, Perry JW, Niggli E, Ellis-Davies GCR. Calcium Uncaging with Visible Light. J Am Chem Soc 2016; 138:3687-93. [PMID: 26974387 DOI: 10.1021/jacs.5b11606] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We have designed a nitroaromatic photochemical protecting group that absorbs visible light in the violet-blue range. The chromophore is a dinitro derivative of bisstyrylthiophene (or BIST) that absorbs light very effectively (ε440 = 66,000 M(-1) cm(-1) and two-photon cross section of 350 GM at 775 nm). We developed a "caged calcium" molecule by conjugation of BIST to a Ca(2+) chelator that upon laser flash photolysis rapidly releases Ca(2+) in <0.2 ms. Using the patch-clamp method the optical probe, loaded with Ca(2+), was delivered into acutely isolated mouse cardiac myocytes, where either one- and two-photon uncaging of Ca(2+) induced highly local or cell-wide physiological Ca(2+) signaling events.
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Affiliation(s)
- Hitesh K Agarwal
- Department of Neuroscience, Mount Sinai School of Medicine , New York, New York 10029, United States
| | - Radoslav Janicek
- Department of Physiology, University of Bern , Bern CH 3012, Switzerland
| | - San-Hui Chi
- School of Chemistry and Biochemistry, Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Joseph W Perry
- School of Chemistry and Biochemistry, Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Ernst Niggli
- Department of Physiology, University of Bern , Bern CH 3012, Switzerland
| | - Graham C R Ellis-Davies
- Department of Neuroscience, Mount Sinai School of Medicine , New York, New York 10029, United States
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Posey AD, Kawalekar OU, June CH. Measurement of intracellular ions by flow cytometry. ACTA ACUST UNITED AC 2015; 72:9.8.1-9.8.21. [PMID: 25827486 DOI: 10.1002/0471142956.cy0908s72] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Using flow cytometry, single-cell measurements of calcium can be made on isolated populations identified by one or more phenotypic characteristics. Most earlier techniques for measuring cellular activation parameters determined the mean value for a population of cells, which did not permit optimal resolution of the responses. The flow cytometer is particularly useful for this purpose because it can measure ion concentrations in large numbers of single cells and thereby allows ion concentration to be correlated with other parameters such as immunophenotype and cell cycle stage. A limitation of flow cytometry, however, is that it does not permit resolution of certain complex kinetic responses such as cellular oscillatory responses. This unit describes the preparation of cells, including labeling with antibodies and with calcium probes, and discusses the principles of data analysis and interpretation.
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Affiliation(s)
- Avery D Posey
- Abramson Family Cancer Research Institute, and the Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Omkar U Kawalekar
- Abramson Family Cancer Research Institute, and the Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Carl H June
- Abramson Family Cancer Research Institute, and the Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
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Yu X, Zhang P, Liu Q, Li Y, Zhen X, Zhang Y, Ma Z. An “off–on” fluorescent and colorimetric probe bearing fluorescein moiety for Mg2+ and Ca2+ via a controlled supramolecular approach. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 39:73-7. [DOI: 10.1016/j.msec.2014.02.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 01/12/2014] [Accepted: 02/17/2014] [Indexed: 10/25/2022]
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Abstract
Increasing interest in detecting metal ions in many chemical and biomedical fields has created demands for developing sensors and imaging agents for metal ions with high sensitivity and selectivity. This review covers recent progress in DNA-based sensors and imaging agents for metal ions. Through both combinatorial selection and rational design, a number of metal-ion-dependent DNAzymes and metal-ion-binding DNA structures that can selectively recognize specific metal ions have been obtained. By attachment of these DNA molecules with signal reporters such as fluorophores, chromophores, electrochemical tags, and Raman tags, a number of DNA-based sensors for both diamagnetic and paramagnetic metal ions have been developed for fluorescent, colorimetric, electrochemical, and surface Raman detection. These sensors are highly sensitive (with a detection limit down to 11 ppt) and selective (with selectivity up to millions-fold) toward specific metal ions. In addition, through further development to simplify the operation, such as the use of "dipstick tests", portable fluorometers, computer-readable disks, and widely available glucose meters, these sensors have been applied for on-site and real-time environmental monitoring and point-of-care medical diagnostics. The use of these sensors for in situ cellular imaging has also been reported. The generality of the combinatorial selection to obtain DNAzymes for almost any metal ion in any oxidation state and the ease of modification of the DNA with different signal reporters make DNA an emerging and promising class of molecules for metal-ion sensing and imaging in many fields of applications.
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Affiliation(s)
- Yu Xiang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Fax: 217-244-3186; Tel: 217-333-2619
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Fax: 217-244-3186; Tel: 217-333-2619
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Gwizdala C, Burdette SC. Following the Ca2+ roadmap to photocaged complexes for Zn2+ and beyond. Curr Opin Chem Biol 2013; 17:137-42. [DOI: 10.1016/j.cbpa.2012.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 11/15/2012] [Accepted: 11/15/2012] [Indexed: 12/30/2022]
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15
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Klán P, Šolomek T, Bochet CG, Blanc A, Givens R, Rubina M, Popik V, Kostikov A, Wirz J. Photoremovable protecting groups in chemistry and biology: reaction mechanisms and efficacy. Chem Rev 2013; 113:119-91. [PMID: 23256727 PMCID: PMC3557858 DOI: 10.1021/cr300177k] [Citation(s) in RCA: 1238] [Impact Index Per Article: 112.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Indexed: 02/06/2023]
Affiliation(s)
- Petr Klán
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
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Cui J, Gropeanu RA, Stevens DR, Rettig J, Campo AD. New Photolabile BAPTA-Based Ca2+ Cages with Improved Photorelease. J Am Chem Soc 2012; 134:7733-40. [DOI: 10.1021/ja2115184] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jiaxi Cui
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128
Mainz, Germany
| | - Radu A. Gropeanu
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128
Mainz, Germany
| | - David R. Stevens
- Physiologisches
Institut, Universität des Saarlandes, 66421 Homburg, Germany
| | - Jens Rettig
- Physiologisches
Institut, Universität des Saarlandes, 66421 Homburg, Germany
| | - Aránzazu del Campo
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128
Mainz, Germany
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17
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Honda T, Momotake A, Arai T. N-Acyl-N-carboxymethyl-2-nitroaniline and its analogues: a new class of water-soluble photolabile precursor of carboxylic acids. Photochem Photobiol Sci 2012; 11:493-6. [DOI: 10.1039/c2pp05322e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Chromophores for the Delivery of Bioactive Molecules with Two-Photon Excitation. NEUROMETHODS 2011. [DOI: 10.1007/978-1-61779-031-7_4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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19
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Ciesienski KL, Franz KJ. Keys for Unlocking Photolabile Metal-Containing Cages. Angew Chem Int Ed Engl 2010; 50:814-24. [DOI: 10.1002/anie.201002542] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Indexed: 01/22/2023]
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20
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Ciesienski KL, Franz KJ. Schlüssel zum Öffnen photolabiler, metallhaltiger Käfige. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201002542] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Obi N, Momotake A, Kanemoto Y, Matsuzaki M, Kasai H, Arai T. 1-Acyl-5-methoxy-8-nitro-1,2-dihydroquinoline: a biologically useful photolabile precursor of carboxylic acids. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2009.12.081] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Planey SL, Zacharias DA. Palmitoyl acyltransferases, their substrates, and novel assays to connect them (Review). Mol Membr Biol 2009; 26:14-31. [DOI: 10.1080/09687680802646703] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Avlonitis N, Chalmers S, McDougall C, Stanton-Humphreys MN, Brown CTA, McCarron JG, Conway SJ. Caged AG10: new tools for spatially predefined mitochondrial uncoupling. MOLECULAR BIOSYSTEMS 2009; 5:450-7. [DOI: 10.1039/b820415m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
A caged molecule is an inert but photosensitive molecule that is transformed by photolysis into a biologically active molecule at high speed (typically 1 msec). The process is referred to as photorelease. The spatial resolution of photorelease is limited by the properties of light; submicrometer resolution is potentially achievable. Therefore, focal photorelease of caged molecules enables one to control biological processes with high spatio-temporal precision. The principles underlying caged molecules as well as practical considerations for their use are discussed in this unit.
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Affiliation(s)
- Joseph P Y Kao
- University of Maryland Biotechnology Institute, Baltimore, Maryland, USA
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26
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Affiliation(s)
- Graham C. R. Ellis-Davies
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 North 15th Street, Philadelphia, Pennsylvania 19102
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27
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Sakata T, Jackson DK, Mao S, Marriott G. Optically switchable chelates: optical control and sensing of metal ions. J Org Chem 2007; 73:227-33. [PMID: 18072788 DOI: 10.1021/jo7019898] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study introduces new concepts in the design, synthesis, and in vitro and in vivo characterization, manipulation, and imaging of organic chelates whose association with metal ions is rapidly and reversibly controlled by using light. Di- and tricarboxylic group bearing photochromes, nitrobenzospiropyran (nitroBIPS), undergo rapid and reversible, optically driven transitions between their spiro (SP) and fluorescent merocyanine (MC) states. The MC state of nitroBIPS-8-DA binds tightly to various metal ions resulting in specific shifts in absorption and fluorescence, and the dissociation constant for its Gadolinium complex in water is measured at approximately 5 microM. The metal-bound MC state is converted to the weaker-binding SP state with use of 543 nm light, while the SP to MC transition is complete with use of 365 or 720 nm (2-photon) light within several microseconds. Fluorescence imaging of the MC state of nitroBIPS-8-TriA was used to quantify the rate and efficiency of optical switching and to provide a real-time readout of the state of the optically switchable chelate within living cells.
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Affiliation(s)
- Tomoyo Sakata
- Department of Physiology, University of Wisconsin, 1300 University Avenue, Madison, Wisconsin 53706, USA
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28
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Ellis-Davies GCR. Caged compounds: photorelease technology for control of cellular chemistry and physiology. Nat Methods 2007; 4:619-28. [PMID: 17664946 PMCID: PMC4207253 DOI: 10.1038/nmeth1072] [Citation(s) in RCA: 710] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Caged compounds are light-sensitive probes that functionally encapsulate biomolecules in an inactive form. Irradiation liberates the trapped molecule, permitting targeted perturbation of a biological process. Uncaging technology and fluorescence microscopy are 'optically orthogonal': the former allows control, and the latter, observation of cellular function. Used in conjunction with other technologies (for example, patch clamp and/or genetics), the light beam becomes a uniquely powerful tool to stimulate a selected biological target in space or time. Here I describe important examples of widely used caged compounds, their design features and synthesis, as well as practical details of how to use them with living cells.
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Affiliation(s)
- Graham C R Ellis-Davies
- Department of Pharmacology & Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.
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29
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Abstract
p-Quinoid cyclopropenone-containing enediyne precursor (1) has been synthesized by monocyclopropanation of one of the triple bonds in p-dimethoxy-substituted 3,4-benzocyclodeca-1,5-diyne followed by oxidative demethylation. Cyclopropenone 1 is stable up to 90 degrees C but readily produces reactive enediyne 2 upon single-photon (Phi(300)(nm) = 0.46) or two-photon (sigma(800 nm) = 0.5 GM) photolysis. The photoproduct 2 undergoes Bergman cyclization at 40 degrees C with the lifetime of 88 h.
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Affiliation(s)
- Andrei Poloukhtine
- Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA
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30
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Abstract
DM-nitrophen is a photolabile derivative of EDTA and therefore functions as either caged Ca(2+) or caged Mg(2+). Several papers have been published recently which use the AM ester to load intact cells with DM-nitrophen; under these conditions it is caged Mg(2+). In this commentary, I give a short history of the development and application of caged Ca(2+) probes, explaining why EGTA and BAPTA-based Ca(2+) cages are to be preferred for the photorelease of Ca(2+) under normal intracellular conditions.
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Affiliation(s)
- Graham C R Ellis-Davies
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA 19102, USA.
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31
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Urdabayev NK, Poloukhtine A, Popik VV. Two-photon induced photodecarbonylation reaction of cyclopropenones. Chem Commun (Camb) 2006:454-6. [PMID: 16493835 DOI: 10.1039/b513248g] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Irradiation of cyclopropenones (1a-c) with 800 nm pulses of ultrafast laser results in a photodecarbonylation reaction via nonresonant two-photon absorption of light.
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Affiliation(s)
- Nurtay K Urdabayev
- Center for Photochemical Sciences, Bowling Green State University, Ohio 43403, USA
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32
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Momotake A, Lindegger N, Niggli E, Barsotti RJ, Ellis-Davies GCR. The nitrodibenzofuran chromophore: a new caging group for ultra-efficient photolysis in living cells. Nat Methods 2005; 3:35-40. [PMID: 16369551 DOI: 10.1038/nmeth821] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Accepted: 10/28/2005] [Indexed: 11/08/2022]
Abstract
Photochemical uncaging of bio-active molecules was introduced in 1977, but since then, there has been no substantial improvement in the properties of generic caging chromophores. We have developed a new chromophore, nitrodibenzofuran (NDBF) for ultra-efficient uncaging of second messengers inside cells. Photolysis of a NDBF derivative of EGTA (caged calcium) is about 16-160 times more efficient than photolysis of the most widely used caged compounds (the quantum yield of photolysis is 0.7 and the extinction coefficient is 18,400 M(-1) cm(-1)). Ultraviolet (UV)-laser photolysis of NDBF-EGTA:Ca(2+) rapidly released Ca(2+) (rate of 20,000 s(-1)) and initiated contraction of skinned guinea pig cardiac muscle. NDBF-EGTA has a two-photon cross-section of approximately 0.6 GM and two-photon photolysis induced localized Ca(2+)-induced Ca(2+) release from the sarcoplasmic recticulum of intact cardiac myocytes. Thus, the NDBF chromophore has great promise as a generic and photochemically efficient protecting group for both one- and two-photon uncaging in living cells.
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Affiliation(s)
- Atsuya Momotake
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 North 15th St., Philadelphia, Pennsylvania 19102, USA
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33
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Ellis-Davies GCR, Barsotti RJ. Tuning caged calcium: photolabile analogues of EGTA with improved optical and chelation properties. Cell Calcium 2005; 39:75-83. [PMID: 16303177 DOI: 10.1016/j.ceca.2005.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 10/02/2005] [Accepted: 10/03/2005] [Indexed: 11/19/2022]
Abstract
The physico-chemical properties of several Ca(2+)-selective, photolabile chelators are described. These molecules have been developed as part of an effort to produce a caged Ca(2+) that improved upon the Ca(2+) chelation properties and light absorption capability of nitrophenyl-EGTA (NP-EGTA). Four dimethoxy-ortho-nitrophenyl derivatives of EGTA (called DMNPE-1 through -4), and one analogue of EGTA (DMNPE-5) have been characterized, each of which is bisected upon irradiation. One of these cages has a higher affinity than NP-EGTA: DMNPE-4 has a K(d) for Ca(2+) of 48 nm at pH 7.2 (19 nM at pH 7.4). Furthermore, this cage has a large extinction coefficient of 5120 M(-1)cm(-1) at 350 nm (cf. 975 M(-1)cm(-1) for NP-EGTA). The other physico-chemical properties of DMNPE-4 are: quantum yield of photolysis of 0.09; bipasic Ca(2+) release kinetics (70% released with a rate of about 48,000 s(-1) and 30% at 1.5s(-1)) and photoproducts that bind Ca(2+) with very low affinity (K(d) in the range of 2mM, pH 7.2), hence most of the bound Ca(2+) is released rapidly and efficiently upon photolysis. Thus, DMNPE-4 has a unique combination of properties that make it an extremely effective Ca(2+) cage.
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Affiliation(s)
- Graham C R Ellis-Davies
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
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34
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Schafer-Hales KJ, Belfield KD, Yao S, Frederiksen PK, Hales JM, Kolattukudy PE. Fluorene-based fluorescent probes with high two-photon action cross-sections for biological multiphoton imaging applications. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:051402. [PMID: 16292939 DOI: 10.1117/1.2104528] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Two-photon fluorescence microscopy is a powerful tool for the study of dynamic cellular processes and live-cell imaging. Many commercially available fluorescent probes have been used in multiphoton-based imaging studies despite exhibiting relatively low two-photon absorption cross-section values in the tunability range of ultrafast Ti:sapphire lasers commonly used in multiphoton microscopy imaging. Furthermore, available fluorophores may be plagued with low fluorescence quantum yield and/or photoinstability (i.e., photobleaching) on exposure to the high peak power and photon density provided by the ultrafast laser source. To address the demand for better performing dyes, we prepare fluorophores tailored for multiphoton imaging. These fluorophores are based on the fluorene ring system, known to exhibit high fluorescence quantum yield (>0.7) and high photostability. Furthermore, an amine-reactive fluorescent probe for the covalent attachment onto amine-containing biomolecules is also prepared. Epi-fluorescence and two-photon fluorescence microscopy images of H9c2 rat cardiomyoblasts stained with an efficient two-photon absorbing fluorene fluorophore is demonstrated. Additionally, single-photon spectral characteristics of the amine-reactive fluorophore, as well as the two-photon absorption cross sections of its model adduct in solution, and spectral characterization of a bovine serum albumin (BSA) as a model bioconjugate are presented.
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Affiliation(s)
- Katherine J Schafer-Hales
- University of Central Florida, Department of Chemistry and Burnett College of Biomedical Sciences, 4000 Central Florida Boulevard, Orlando, Florida 32816, USA
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35
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36
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Affiliation(s)
- Victoria E Centonze
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA
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37
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Abstract
Several caged calciums have been synthesized since 1986, and three are commercially available: DM-nitrophen, NP-EGTA, and nitr-5. Each of these caged compounds has uniquely useful properties, making the choice of which cage to use dependent on the specific experiment (i.e., the cell type and divalent cation requirements of the experiments within purview). Significantly, methods have been developed for all three cages that permit their quantitative use inside many cell types, including those with some of the most demanding of requirements for experiments with caged calcium, namely, in relating presynaptic [Ca] to postsynaptic function. The success of such experiments using DM-nitrophen and NP-EGTA suggests that caged calcium is now a mature tool for cellular physiology and neurobiology.
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Affiliation(s)
- Graham C R Ellis-Davies
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
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38
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Lu Y, Liu J, Li J, Bruesehoff PJ, Pavot CMB, Brown AK. New highly sensitive and selective catalytic DNA biosensors for metal ions. Biosens Bioelectron 2003; 18:529-40. [PMID: 12706559 DOI: 10.1016/s0956-5663(03)00013-7] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
While remarkable progress has been made in developing sensors for metal ions such as Ca(II) and Zn(II), designing and synthesizing sensitive and selective metal ion sensors remains a significant challenge. Perhaps the biggest challenge is the design and synthesis of a sensor capable of specific and strong metal binding. Since our knowledge about the construction of metal-binding sites in general is limited, searching for sensors in a combinatorial way is of significant value. Therefore, we have been able to use a combinatorial method called in vitro selection to obtain catalytic DNA that can bind a metal ion of choice strongly and specifically. The metal ion selectivity of the catalytic DNA was further improved using a 'negative selection' strategy where catalytic DNA that are selective for competing metal ions are discarded in the in vitro selection processes. By labeling the resulting catalytic DNA with a fluorophore/quencher pair, we have made a new class of metal ion fluorescent sensors that are the first examples of catalytic DNA biosensors for metal ions. The sensors combine the high selectivity of catalytic DNA with the high sensitivity of fluorescent detection, and can be applied to the quantitative detection of metal ions over a wide concentration range and with high selectivity. The use of DNA sensors in detection and quantification of lead ions in environmental samples such as water from Lake Michigan has been demonstrated. DNA is stable, cost-effective, environmentally benign, and easily adaptable to optical fiber and microarray technology for device manufacture. Thus, the DNA sensors explained here hold great promise for on-site and real-time monitoring of metal ions in the fields of environmental monitoring, developmental biology, clinical toxicology, wastewater treatment, and industrial process monitoring.
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Affiliation(s)
- Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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39
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Pelliccioli AP, Wirz J. Photoremovable protecting groups: reaction mechanisms and applications. Photochem Photobiol Sci 2002; 1:441-58. [PMID: 12659154 DOI: 10.1039/b200777k] [Citation(s) in RCA: 538] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photolabile protecting groups enable biochemists to control the release of bioactive compounds in living tissue. 'Caged compounds' (photoactivatable bioagents) have become an important tool to study the events that follow chemical signalling in, e.g., cell biology and the neurosciences. The possibilities are by no means exhausted. Progress will depend on the development of photoremovable protecting groups that satisfy the diverse requirements of new applications--a challenging task for photochemists.
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Affiliation(s)
- Anna Paola Pelliccioli
- Institut für Physikalische Chemie, Universität Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
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40
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Abstract
Biochemistry in the context of a living cell or organism is complicated by many variables such as supramolecular organization, cytoplasmic viscosity, and substrate heterogeneity. While these variables are easily excluded or avoided in reconstituted systems, they must be dealt with in cellular environments. New developments have allowed researchers to begin probing the inner workings of the cell to gain new insight into cell function and metabolism. Advances in cellular imaging and in small molecule-controlled gene expression, signal transduction and cell surface modification are discussed in this review. These techniques have permitted the study of molecular components within the context of living cells.
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Affiliation(s)
- Brian N Cook
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
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41
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Shogren-Knaak MA, Alaimo PJ, Shokat KM. Recent advances in chemical approaches to the study of biological systems. Annu Rev Cell Dev Biol 2002; 17:405-33. [PMID: 11687495 DOI: 10.1146/annurev.cellbio.17.1.405] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A number of novel chemical methods for studying biological systems have recently been developed that provide a means of addressing biological questions not easily studied with other techniques. In this review, examples that highlight the development and use of such chemical approaches are discussed. Specifically, strategies for modulating protein activity or protein-protein interactions using small molecules are presented. In addition, methods for generating and utilizing novel biomolecules (proteins, oligonucleotides, oligosaccharides, and second messengers) are examined.
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Affiliation(s)
- M A Shogren-Knaak
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94143-0450, USA
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42
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Abstract
Two-photon molecular excitation microscopy has several advantages over conventional confocal fluorescence microscopy, including the ability to section deeper into scattering samples and to allow spatially resolved flash photolysis. We describe and examine the benefit of incorporating non-descanned fluorescence detection in our microscope system. In a scattering sample where almost no signal could be obtained at a depth of 50 microm with confocal detection, non-descanned detection resulted in an improvement of signal strength by more than an order of magnitude at depths >40 microm. The spatio-temporal properties of stationary spot two-photon excited flash photolysis (TPEFP) in drops of test solutions and cardiac myocytes were also examined. At input powers that produce >10% of the maximum rate of DM-nitrophen photolysis, serious photodestruction of the reporter fluorochrome (Fluo-3) at the photolysis spot occurred. At power levels of approximately 4 mW for periods <50 ms, we were able to produce small repeatable calcium release events using DM-nitrophen in cardiac myocytes, which were similar to naturally occurring calcium sparks. The properties of these artificial calcium sparks were very similar to signals obtained from drops of test solutions, suggesting that the apparent rate of calcium diffusion in myocytes is similar to the rate of diffusion of Fluo-3 in solution. Using TPEFP, we also examined the ability of a combination of EGTA and a low-affinity calcium indicator to track the time course of calcium release. Although the addition of EGTA improved the temporal fidelity of the rise of the calcium signal, it did not significantly reduce the spread of the fluorescence signal from the photolysis spot.
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Affiliation(s)
- C Soeller
- Department of Physiology, School of Medicine and Health Sciences, University of Auckland, Auckland, New Zealand
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43
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Furuta T, Wang SS, Dantzker JL, Dore TM, Bybee WJ, Callaway EM, Denk W, Tsien RY. Brominated 7-hydroxycoumarin-4-ylmethyls: photolabile protecting groups with biologically useful cross-sections for two photon photolysis. Proc Natl Acad Sci U S A 1999; 96:1193-200. [PMID: 9990000 PMCID: PMC15439 DOI: 10.1073/pnas.96.4.1193] [Citation(s) in RCA: 484] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/1998] [Indexed: 11/18/2022] Open
Abstract
Photochemical release (uncaging) of bioactive messengers with three-dimensional spatial resolution in light-scattering media would be greatly facilitated if the photolysis could be powered by pairs of IR photons rather than the customary single UV photons. The quadratic dependence on light intensity would confine the photolysis to the focus point of the laser, and the longer wavelengths would be much less affected by scattering. However, previous caged messengers have had very small cross sections for two-photon excitation in the IR region. We now show that brominated 7-hydroxycoumarin-4-ylmethyl esters and carbamates efficiently release carboxylates and amines on photolysis, with one- and two-photon cross sections up to one or two orders of magnitude better than previously available. These advantages are demonstrated on neurons in brain slices from rat cortex and hippocampus excited by glutamate uncaged from N-(6-bromo-7-hydroxycoumarin-4-ylmethoxycarbonyl)-L-glutamate (Bhc-glu). Conventional UV photolysis of Bhc-glu requires less than one-fifth the intensities needed by one of the best previous caged glutamates, gamma-(alpha-carboxy-2-nitrobenzyl)-L-glutamate (CNB-glu). Two-photon photolysis with raster-scanned femtosecond IR pulses gives the first three-dimensionally resolved maps of the glutamate sensitivity of neurons in intact slices. Bhc-glu and analogs should allow more efficient and three-dimensionally localized uncaging and photocleavage, not only in cell biology and neurobiology but also in many technological applications.
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Affiliation(s)
- T Furuta
- Department of Pharmacology, University of California, San Diego, CA 92093-0647, USA
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44
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Brown EB, Shear JB, Adams SR, Tsien RY, Webb WW. Photolysis of caged calcium in femtoliter volumes using two-photon excitation. Biophys J 1999; 76:489-99. [PMID: 9876162 PMCID: PMC1302539 DOI: 10.1016/s0006-3495(99)77217-6] [Citation(s) in RCA: 148] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
A new technique for the determination of the two-photon uncaging action cross section (deltau) of photolyzable calcium cages is described. This technique is potentially applicable to other caged species that can be chelated by a fluorescent indicator dye, as well as caged fluorescent compounds. The two-photon action cross sections of three calcium cages, DM-nitrophen, NP-EGTA, and azid-1, are studied in the range of excitation wavelengths between 700 and 800 nm. Azid-1 has a maximum deltau of approximately 1.4 GM at 700 nm, DM-nitrophen has a maximum deltau of approximately 0.013 GM at 730 nm, and NP-EGTA has no measurable uncaging yield. The equations necessary to predict the amount of cage photolyzed and the temporal behavior of the liberated calcium distribution under a variety of conditions are derived. These equations predict that by using 700-nm light from a Ti:sapphire laser focused with a 1.3-NA objective, essentially all of the azid-1 within the two-photon focal volume would be photolyzed with a 10-micros pulse train of approximately 7 mW average power. The initially localized distributions of free calcium will dissipate rapidly because of diffusion of free calcium and uptake by buffers. In buffer-free cytoplasm, the elevation of the calcium concentration at the center of the focal volume is expected to last for approximately 165 micros.
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Affiliation(s)
- E B Brown
- Developmental Resource for Biophysical Imaging and Optoelectronics, Cornell University, Ithaca, New York 14853, USA
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45
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Winans KA, Bertozzi CR. Inner space exploration: the chemical biologist's guide to the cell. CHEMISTRY & BIOLOGY 1998; 5:R313-5. [PMID: 9862801 DOI: 10.1016/s1074-5521(98)90658-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- K A Winans
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
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46
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Brown EB, Webb WW. Two-photon activation of caged calcium with submicron, submillisecond resolution. Methods Enzymol 1998; 291:356-80. [PMID: 9661159 DOI: 10.1016/s0076-6879(98)91023-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- E B Brown
- Department of Physics, Cornell University, Ithaca, New York 14853, USA
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