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Ellis-Davies GCR. Reverse Engineering Caged Compounds: Design Principles for their Application in Biology. Angew Chem Int Ed Engl 2023; 62:e202206083. [PMID: 36646644 PMCID: PMC10015297 DOI: 10.1002/anie.202206083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Indexed: 01/18/2023]
Abstract
Light passes through biological tissue, and so it is used for imaging biological processes in situ. Such observation is part of the very essence of science, but mechanistic understanding requires intervention. For more than 50 years a "second function" for light has emerged; namely, that of photochemical control. Caged compounds are biologically inert signaling molecules that are activated by light. These optical probes enable external instruction of biological processes by stimulation of an individual element in complex signaling cascades in its native environment. Cause and effect are linked directly in spatial, temporal, and frequency domains in a quantitative manner by their use. I provide a guide to the basic properties required to make effective caged compounds for the biological sciences.
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Affiliation(s)
- Graham C R Ellis-Davies
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, (Previously, Mount Sinai School of Medicine), 10029, New York, NY, USA
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2
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Ellis‐Davies GCR. Reverse Engineering Caged Compounds: Design Principles for their Application in Biology. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/ange.202206083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Graham C. R. Ellis‐Davies
- Department of Neuroscience Icahn School of Medicine at Mount Sinai (Previously, Mount Sinai School of Medicine) 10029 New York NY USA
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3
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Bramham JE, Zalar M, Golovanov AP. Controlled release and characterisation of photocaged molecules using in situ LED illumination in solution NMR spectroscopy. Chem Commun (Camb) 2022; 58:11973-11976. [DOI: 10.1039/d2cc04731d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate that photo-uncaging reactions triggered by LED illumination can be conveniently monitored in situ by solution NMR, offering new ways to characterise and optimise photocages.
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Affiliation(s)
- Jack E. Bramham
- Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester, M13 9PL, UK
| | - Matja Zalar
- Department of Chemical Engineering, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester, M13 9PL, UK
| | - Alexander P. Golovanov
- Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester, M13 9PL, UK
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Weinstain R, Slanina T, Kand D, Klán P. Visible-to-NIR-Light Activated Release: From Small Molecules to Nanomaterials. Chem Rev 2020; 120:13135-13272. [PMID: 33125209 PMCID: PMC7833475 DOI: 10.1021/acs.chemrev.0c00663] [Citation(s) in RCA: 261] [Impact Index Per Article: 65.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Indexed: 02/08/2023]
Abstract
Photoactivatable (alternatively, photoremovable, photoreleasable, or photocleavable) protecting groups (PPGs), also known as caged or photocaged compounds, are used to enable non-invasive spatiotemporal photochemical control over the release of species of interest. Recent years have seen the development of PPGs activatable by biologically and chemically benign visible and near-infrared (NIR) light. These long-wavelength-absorbing moieties expand the applicability of this powerful method and its accessibility to non-specialist users. This review comprehensively covers organic and transition metal-containing photoactivatable compounds (complexes) that absorb in the visible- and NIR-range to release various leaving groups and gasotransmitters (carbon monoxide, nitric oxide, and hydrogen sulfide). The text also covers visible- and NIR-light-induced photosensitized release using molecular sensitizers, quantum dots, and upconversion and second-harmonic nanoparticles, as well as release via photodynamic (photooxygenation by singlet oxygen) and photothermal effects. Release from photoactivatable polymers, micelles, vesicles, and photoswitches, along with the related emerging field of photopharmacology, is discussed at the end of the review.
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Affiliation(s)
- Roy Weinstain
- School
of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 6997801, Israel
| | - Tomáš Slanina
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic
| | - Dnyaneshwar Kand
- School
of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 6997801, Israel
| | - Petr Klán
- Department
of Chemistry and RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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Abstract
Light has been instrumental in the study of living cells since its use helped in their discovery in the late 17th century. Further, combining chemical technology with light microscopy was an essential part of the Nobel Prize for Physiology in 1906. Such landmark scientific findings involved passive observation of cells. However, over the past 50 years, a "second use" of light has emerged in cell physiology, namely one of rational control. The seminal method for this emerged in late 1970s with the invention of caged compounds. This was the point when "caged compounds" were defined as optical probes in which the active functionality of a physiological signaling molecule was blocked with a photochemical protecting group. Caged compounds are analogous to prodrugs; in both, the activity of the effector is latent. However, caged compounds, unlike prodrugs, use a trigger that confers the power of full temporal and spatial manipulation of the effects of release of its latent biological cargo. Light is distinct because it is bio-orthogonal, passes through living tissue (even into the cell interior), and initiates rapid release of the "caged" biomolecule. Further, because light can be directed to broad areas or focused to small points, caged compounds offer an array of timing scenarios for physiologists to dissect virtually any type of cellular process.The collaborative interaction between chemists and physiologists plays a fundamental role in the development of caged compounds. First, the physiologists must define the problem to be addressed; then, with the help of chemists, decide if a caged compound would be useful. For this, structure-activity relationships of the potential optical probe and receptor must be determined. If rational targets seem feasible, synthetic organic chemistry is used to make the caged compound. The crucial property of prephotolysis bio-inertness relies on physiological or biochemical assays. Second, detailed optical characterization of the caged compound requires the skill of photochemists because the rate and efficiency of uncaging are also crucial properties for a useful caged compound. Often, these studies reveal limitations in the caged compound which has been developed; thus, chemists and physiologists use their abilities for iterative development of even more powerful optical probes. A similar dynamic will be familiar to scientists in the pharmaceutical industry. Therefore, caged compound development provides an excellent training framework for (young) chemists both intellectually and professionally. In this Account, I draw on my long experience in the field of making useful caged compounds for cell physiology by showing how each probe I have developed has been defined by an important physiological problem. Fundamental to this process has been my initial training by the pioneers in aromatic photochemistry, Derek Bryce-Smith and Andrew Gilbert. I discuss making a range of "caged calcium" probes, ones which went on to be the most widely used of all caged compounds. Then, I describe the development of caged neurotransmitters for two-photon uncaging microscopy. Finally, I survey recent work on making new photochemical protecting groups for wavelength orthogonal, two-color, and ultraefficient two-photon uncaging.
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Affiliation(s)
- Graham C R Ellis-Davies
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029, United States
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Cozzolino M, Bazzurro V, Gatta E, Bianchini P, Angeli E, Robello M, Diaspro A. Precise 3D modulation of electro-optical parameters during neurotransmitter uncaging experiments with neurons in vitro. Sci Rep 2020; 10:13380. [PMID: 32770032 PMCID: PMC7414112 DOI: 10.1038/s41598-020-70217-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 07/13/2020] [Indexed: 11/23/2022] Open
Abstract
Ruthenium–bipyridinetriphenylphosphine–GABA (RuBi–GABA) is a caged compound that allows studying the neuronal transmission in a specific region of a neuron. The inhibitory neurotransmitter γ-aminobutyric acid (GABA) is bound to a caged group that blocks the interaction of the neurotransmitter with its receptor site. Following linear—one-photon (1P)—and non-linear—multi-photon—absorption of light, the covalent bond of the caged molecule is broken, and GABA is released. Such a controlled release in time and space allows investigating the interaction with its receptor in four dimensions (X,Y,Z,t). Taking advantage of this strategy, we succeeded in addressing the modulation of GABAA in rat cerebellar neurons by coupling the photoactivation process, by confocal or two-photon excitation microscopy, with the electrophysiological technique of the patch-clamp in the whole-cell configuration. Key parameters have been comprehensively investigated and correlated in a temporally and spatially confined way, namely: photoactivation laser power, time of exposure, and distance of the uncaging point from the cell of interest along the X, Y, Z spatial coordinates. The goal of studying specific biological events as a function of controlled physical parameters has been achieved.
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Affiliation(s)
- Marco Cozzolino
- DIFILAB, Department of Physics, University of Genoa, via Dodecaneso 33, 16143, Genoa, Italy.,Nanoscopy, CHT Erzelli, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Virginia Bazzurro
- DIFILAB, Department of Physics, University of Genoa, via Dodecaneso 33, 16143, Genoa, Italy
| | - Elena Gatta
- DIFILAB, Department of Physics, University of Genoa, via Dodecaneso 33, 16143, Genoa, Italy
| | - Paolo Bianchini
- Nanoscopy, CHT Erzelli, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Elena Angeli
- DIFILAB, Department of Physics, University of Genoa, via Dodecaneso 33, 16143, Genoa, Italy
| | - Mauro Robello
- DIFILAB, Department of Physics, University of Genoa, via Dodecaneso 33, 16143, Genoa, Italy
| | - Alberto Diaspro
- DIFILAB, Department of Physics, University of Genoa, via Dodecaneso 33, 16143, Genoa, Italy. .,Nanoscopy, CHT Erzelli, Istituto Italiano di Tecnologia, Genoa, Italy.
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Abstract
Glutamate is the major excitatory neurotransmitter in the brain, and photochemical release of glutamate (or uncaging) is a chemical technique widely used by biologists to interrogate its physiology. A basic prerequisite of these optical probes is bio-inertness before photolysis. However, all caged glutamates are known to have strong antagonism toward receptors of γ-aminobutyric acid, the major inhibitory transmitter. We have developed a caged glutamate probe that is inert toward these receptors at concentrations that are effective for photolysis with violet light. Pharmacological tests in vitro revealed that attachment of a fifth-generation (G5) dendrimer (i.e., cloaking) to the widely used 4-methoxy-7-nitro-indolinyl(MNI)-Glu probe prevented such off-target effects while not changing the photochemical properties of MNI-Glu significantly. G5-MNI-Glu was used with optofluidic delivery to stimulate dopamine neurons of the ventral tegmental area of freely moving mice in a conditioned place-preference protocol so as to mediate Pavlovian conditioning.
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Shin JE, Ogunyankin MO, Zasadzinski JA. Near Infrared-Triggered Liposome Cages for Rapid, Localized Small Molecule Delivery. Sci Rep 2020; 10:1706. [PMID: 32015363 PMCID: PMC6997424 DOI: 10.1038/s41598-020-58764-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 01/17/2020] [Indexed: 11/09/2022] Open
Abstract
Photolabile chelating cages or protecting groups need complex chemical syntheses and require UV, visible, or two-photon NIR light to trigger release. Different cages have different solubilities, reaction rates, and energies required for triggering. Here we show that liposomes containing calcium, adenosine triphosphate, or carboxyfluorescein are tethered to plasmon-resonant hollow gold nanoshells (HGN) tuned to absorb light from 650-950 nm. Picosecond pulses of near infrared (NIR) light provided by a two-photon microscope, or by a stand-alone laser during flow through microfluidic channels, trigger contents release with spatial and temporal control. NIR light adsorption heats the HGN, inducing vapor nanobubbles that rupture the liposome, releasing cargo within milliseconds. Any water-soluble molecule can be released at essentially the same rate from the liposome-HGN. By using liposomes of different composition, or HGN of different sizes or shapes with different nanobubble threshold fluences, or irradiating on or off resonance, two different cargoes can be released simultaneously, one before the other, or in a desired ratio. Calcium release from liposome-HGN can be spatially patterned to crosslink alginate gels and trap living cells. Liposome-HGN provide stable, biocompatible isolation of the bioactive compound from its surroundings with minimal interactions with the local environment.
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Affiliation(s)
- Jeong Eun Shin
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Maria O Ogunyankin
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, 55455, USA.,Bristol, Myers, Squibb, 1 Squibb Drive, New Brunswick, NJ, 08902, USA
| | - Joseph A Zasadzinski
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, 55455, USA.
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Sitkowska K, Hoes MF, Lerch MM, Lameijer LN, van der Meer P, Szymański W, Feringa BL. Red-light-sensitive BODIPY photoprotecting groups for amines and their biological application in controlling heart rhythm. Chem Commun (Camb) 2020; 56:5480-5483. [DOI: 10.1039/d0cc02178d] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Protection of amine functionality with a BODIPY-derived photocleavable protecting group enables the control of heart beat frequency with red light.
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Affiliation(s)
- Kaja Sitkowska
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
| | - Martijn F. Hoes
- Department of Cardiology
- University of Groningen
- University Medical Centre Groningen
- 9713 GZ Groningen
- The Netherlands
| | - Michael M. Lerch
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
| | - Lucien N. Lameijer
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
| | - Peter van der Meer
- Department of Cardiology
- University of Groningen
- University Medical Centre Groningen
- 9713 GZ Groningen
- The Netherlands
| | - Wiktor Szymański
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
| | - Ben L. Feringa
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
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Richers MT, Passlick S, Agarwal H, Ellis‐Davies GCR. Dendrimer Conjugation Enables Multiphoton Chemical Neurophysiology Studies with an Extended π‐Electron Caging Chromophore. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Matthew T. Richers
- Department of NeuroscienceMount Sinai School of Medicine New York NY 10029 USA
| | - Stefan Passlick
- Department of NeuroscienceMount Sinai School of Medicine New York NY 10029 USA
| | - Hitesh Agarwal
- Department of NeuroscienceMount Sinai School of Medicine New York NY 10029 USA
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11
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Richers MT, Passlick S, Agarwal H, Ellis-Davies GCR. Dendrimer Conjugation Enables Multiphoton Chemical Neurophysiology Studies with an Extended π-Electron Caging Chromophore. Angew Chem Int Ed Engl 2019; 58:12086-12090. [PMID: 31216109 PMCID: PMC6707848 DOI: 10.1002/anie.201906067] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Indexed: 12/19/2022]
Abstract
We have developed a caged neurotransmitter using an extended π-electron chromophore for efficient multiphoton uncaging on living neurons. Widely studied in a chemical context, such chromophores are inherently bioincompatible due to their highly lipophilic character. Attachment of two polycarboxylate dendrimers, a method we call "cloaking", to a bisstyrylthiophene (or BIST) core effectively transformed the chromophore into a water-soluble optical probe, whilst maintaining the high two-photon absorption of over 500 GM. Importantly, the cloaked caged compound was biologically inert at the high concentrations required for multiphoton chemical physiology. Thus, in contrast to non-cloaked BIST compounds, the BIST-caged neurotransmitter can be safely delivered onto neurons in acutely isolated brain slices, thereby enabling high-resolution two-photon uncaging without any side effects. We expect that our cloaking method will enable the development of new classes of cell-compatible photolabile probes using a wide variety of extended π-electron caging chromophores.
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Affiliation(s)
- Matthew T Richers
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, 10029, USA
| | - Stefan Passlick
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, 10029, USA
| | - Hitesh Agarwal
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, 10029, USA
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Passlick S, Ellis-Davies GCR. Chromatically independent, two-color uncaging of glutamate and GABA with one- or two-photon excitation. Methods Enzymol 2019; 624:167-196. [PMID: 31370929 DOI: 10.1016/bs.mie.2019.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Caged compounds enable fast, light-induced, and spatially-defined application of bioactive molecules to cells. Covalent attachment of a caging chromophore to a crucial functionality of a biomolecule renders it inert, while short pulses of light release the caged molecule in its active form. Caged neurotransmitters have been widely used to study diverse neurobiological processes such as receptor distribution, synaptogenesis, transport, and long-term potentiation. Since the neurotransmitters glutamate and gamma-aminobutyric acid (GABA) are the most important, they have been studied extensively using uncaging. However, to be able to probe their interactions on a physiologically relevant timescale, fast and independent application of both neurotransmitters in an arbitrary order is desired. This can be achieved by combining two caging chromophores absorbing non-overlapping and thus orthogonal wavelengths of light, which enables the precise application of two caged molecules to the same preparation in any order, a technique called two-color uncaging. In this chapter, we describe the principles of orthogonal two-color uncaging with one- and two-photon excitation with an emphasis on caged glutamate and GABA. We then give a guide to its practical application and highlight some key studies utilizing this technique.
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Affiliation(s)
- Stefan Passlick
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, United States; Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany.
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Pálfi D, Chiovini B, Szalay G, Kaszás A, Turi GF, Katona G, Ábrányi-Balogh P, Szőri M, Potor A, Frigyesi O, Lukácsné Haveland C, Szadai Z, Madarász M, Vasanits-Zsigrai A, Molnár-Perl I, Viskolcz B, Csizmadia IG, Mucsi Z, Rózsa B. High efficiency two-photon uncaging coupled by the correction of spontaneous hydrolysis. Org Biomol Chem 2019; 16:1958-1970. [PMID: 29497727 DOI: 10.1039/c8ob00025e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-photon (TP) uncaging of neurotransmitter molecules is the method of choice to mimic and study the subtleties of neuronal communication either in the intact brain or in slice preparations. However, the currently available caged materials are just at the limit of their usability and have several drawbacks. The local and focal nature of their use may for example be jeopardized by a high spontaneous hydrolysis rate of the commercially available compounds with increased photochemical release rate. Here, using quantum chemical modelling we show the mechanisms of hydrolysis and two-photon activation, and synthesized more effective caged compounds. Furthermore, we have developed a new enzymatic elimination method removing neurotransmitters inadvertently escaping from their compound during experiment. This method, usable both in one and two-photon experiments, allows for the use of materials with an increased rate of photochemical release. The efficiency of the new compound and the enzymatic method and of the new compound are demonstrated in neurophysiological experiments.
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Affiliation(s)
- Dénes Pálfi
- Two-Photon Measurement Technology Research Group, The Faculty of Information Technology, Pázmány Péter Catholic University, Práter str 50, H-1083 Budapest, Hungary
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