1
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Schuhmann F, Ramsay JL, Kattnig DR, Solov’yov IA. Structural Rearrangements of Pigeon Cryptochrome 4 Undergoing a Complete Redox Cycle. J Phys Chem B 2024; 128:3844-3855. [PMID: 38568745 PMCID: PMC11056986 DOI: 10.1021/acs.jpcb.4c00424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 03/04/2024] [Accepted: 03/11/2024] [Indexed: 04/26/2024]
Abstract
Cryptochrome is currently the major contender of a protein to underpin magnetoreception, the ability to sense the Earth's magnetic field. Among various types of cryptochromes, cryptochrome 4 has been identified as the likely magnetoreceptor in migratory birds. All-atom molecular dynamics (MD) studies have offered first insights into the structural dynamics of cryptochrome but are limited to a short time scale due to large computational demands. Here, we employ coarse-grained MD simulations to investigate the emergence of long-lived states and conformational changes in pigeon cryptochrome 4. Our coarse-grained simulations complete the picture by permitting observation on a significantly longer time scale. We observe conformational transitions in the phosphate-binding loop of pigeon cryptochrome 4 upon activation and identify prominent motions in residues 440-460, suggesting a possible role as a signaling state of the protein or as a gated interaction site for forming protein complexes that might facilitate downstream processes. The findings highlight the importance of considering longer time scales in studying cryptochrome dynamics and magnetoreception. Coarse-grained MD simulations offer a valuable tool to unravel the complex behavior of cryptochrome proteins and shed new light on the mechanisms underlying their role in magnetoreception. Further exploration of these conformational changes and their functional implications may contribute to a deeper understanding of the molecular mechanisms of magnetoreception in birds.
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Affiliation(s)
- Fabian Schuhmann
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, Carl-von-Ossietzky Str. 9-11, Oldenburg 26129, Germany
- Niels
Bohr International Academy, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen 2100, Denmark
| | - Jessica L. Ramsay
- Living
Systems Institute and Department of Physics, University of Exeter, Stocker Rd., Exeter EX4
4QD, U.K.
| | - Daniel R. Kattnig
- Living
Systems Institute and Department of Physics, University of Exeter, Stocker Rd., Exeter EX4
4QD, U.K.
| | - Ilia A. Solov’yov
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, Carl-von-Ossietzky Str. 9-11, Oldenburg 26129, Germany
- Research
Centre for Neurosensory Science, Carl von
Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, Oldenburg 26129, Germany
- Center
for Nanoscale Dynamics (CENAD), Carl von
Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, Oldenburg 26129, Germany
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2
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Aguida B, Babo J, Baouz S, Jourdan N, Procopio M, El-Esawi MA, Engle D, Mills S, Wenkel S, Huck A, Berg-Sørensen K, Kampranis SC, Link J, Ahmad M. 'Seeing' the electromagnetic spectrum: spotlight on the cryptochrome photocycle. FRONTIERS IN PLANT SCIENCE 2024; 15:1340304. [PMID: 38495372 PMCID: PMC10940379 DOI: 10.3389/fpls.2024.1340304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/12/2024] [Indexed: 03/19/2024]
Abstract
Cryptochromes are widely dispersed flavoprotein photoreceptors that regulate numerous developmental responses to light in plants, as well as to stress and entrainment of the circadian clock in animals and humans. All cryptochromes are closely related to an ancient family of light-absorbing flavoenzymes known as photolyases, which use light as an energy source for DNA repair but themselves have no light sensing role. Here we review the means by which plant cryptochromes acquired a light sensing function. This transition involved subtle changes within the flavin binding pocket which gave rise to a visual photocycle consisting of light-inducible and dark-reversible flavin redox state transitions. In this photocycle, light first triggers flavin reduction from an initial dark-adapted resting state (FADox). The reduced state is the biologically active or 'lit' state, correlating with biological activity. Subsequently, the photoreduced flavin reoxidises back to the dark adapted or 'resting' state. Because the rate of reoxidation determines the lifetime of the signaling state, it significantly modulates biological activity. As a consequence of this redox photocycle Crys respond to both the wavelength and the intensity of light, but are in addition regulated by factors such as temperature, oxygen concentration, and cellular metabolites that alter rates of flavin reoxidation even independently of light. Mechanistically, flavin reduction is correlated with conformational change in the protein, which is thought to mediate biological activity through interaction with biological signaling partners. In addition, a second, entirely independent signaling mechanism arises from the cryptochrome photocycle in the form of reactive oxygen species (ROS). These are synthesized during flavin reoxidation, are known mediators of biotic and abiotic stress responses, and have been linked to Cry biological activity in plants and animals. Additional special properties arising from the cryptochrome photocycle include responsivity to electromagnetic fields and their applications in optogenetics. Finally, innovations in methodology such as the use of Nitrogen Vacancy (NV) diamond centers to follow cryptochrome magnetic field sensitivity in vivo are discussed, as well as the potential for a whole new technology of 'magneto-genetics' for future applications in synthetic biology and medicine.
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Affiliation(s)
- Blanche Aguida
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
| | - Jonathan Babo
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
| | - Soria Baouz
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
| | - Nathalie Jourdan
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
| | - Maria Procopio
- Department of Biophysics, Faculty of Arts and Sciences, Johns Hopkins University, Baltimore, MD, United States
| | | | - Dorothy Engle
- Biology Department, Xavier University, Cincinnati, OH, United States
| | - Stephen Mills
- Chemistry Department, Xavier University, Cincinnati, OH, United States
| | - Stephan Wenkel
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Alexander Huck
- DTU Physics, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Sotirios C. Kampranis
- Biochemical Engineering Group, Plant Biochemistry Section, Department of Plant and Environment Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Justin Link
- Physics and Engineering Department, Cincinnati, OH, United States
| | - Margaret Ahmad
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
- Biology Department, Xavier University, Cincinnati, OH, United States
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3
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Lohof AM, Dufor T, Sherrard RM. Neural Circuit Repair by Low-Intensity rTMS. CEREBELLUM (LONDON, ENGLAND) 2022; 21:750-754. [PMID: 35023064 DOI: 10.1007/s12311-021-01354-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/25/2021] [Indexed: 06/14/2023]
Abstract
Electromagnetic brain stimulation is a promising treatment in neurology and psychiatry. However, clinical outcomes are variable and underlying mechanisms remain ill-defined, impeding the development of new effective stimulation protocols. There is increasing application of repetitive transcranial magnetic stimulation (rTMS) to the cerebellum to induce forebrain plasticity through its long-distance cerebello-cerebral circuits. To better understand what magnetic stimulation does within the cerebellum, we have developed tools to generate defined low-intensity (LI) magnetic fields and deliver them in vivo, in 3D organotypic culture and in primary cultures, over a range of stimulation parameters. Here we show that low-intensity rTMS (LI-rTMS) to the cerebellum induces axon growth and synapse formation providing olivocerebellar reinnervation. This repair depends on stimulation pattern, with complex biomimetic patterns being most effective, and this requires the presence of a cellular magnetoreceptor, cryptochrome. To explain these reparative changes, we found that repair-promoting LI-rTMS patterns, but not ineffective ones, increased c-fos expression in Purkinje neurons, consistent with the production of reactive oxygen species by activated cryptochrome. Rather than activating neurons via induced electric currents, we propose that weak magnetic fields act through cryptochrome, activating intracellular signals that induce climbing fibre-Purkinje cell reinnervation. This information opens new routes to optimize cerebellar magnetic stimulation and its potential role as an effective treatment for neurological diseases.
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Affiliation(s)
- A M Lohof
- Sorbonne Université and CNRS, IBPS-B2A UMR8256 Biological Adaptation and Ageing, Boite 256, 9 Quai St Bernard, 75005, Paris, France
| | - T Dufor
- Sorbonne Université and CNRS, IBPS-B2A UMR8256 Biological Adaptation and Ageing, Boite 256, 9 Quai St Bernard, 75005, Paris, France
| | - R M Sherrard
- Sorbonne Université and CNRS, IBPS-B2A UMR8256 Biological Adaptation and Ageing, Boite 256, 9 Quai St Bernard, 75005, Paris, France.
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4
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Zadeh-Haghighi H, Simon C. Magnetic field effects in biology from the perspective of the radical pair mechanism. J R Soc Interface 2022; 19:20220325. [PMID: 35919980 PMCID: PMC9346374 DOI: 10.1098/rsif.2022.0325] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/14/2022] [Indexed: 04/07/2023] Open
Abstract
Hundreds of studies have found that weak magnetic fields can significantly influence various biological systems. However, the underlying mechanisms behind these phenomena remain elusive. Remarkably, the magnetic energies implicated in these effects are much smaller than thermal energies. Here, we review these observations, and we suggest an explanation based on the radical pair mechanism, which involves the quantum dynamics of the electron and nuclear spins of transient radical molecules. While the radical pair mechanism has been studied in detail in the context of avian magnetoreception, the studies reviewed here show that magnetosensitivity is widespread throughout biology. We review magnetic field effects on various physiological functions, discussing static, hypomagnetic and oscillating magnetic fields, as well as isotope effects. We then review the radical pair mechanism as a potential unifying model for the described magnetic field effects, and we discuss plausible candidate molecules for the radical pairs. We review recent studies proposing that the radical pair mechanism provides explanations for isotope effects in xenon anaesthesia and lithium treatment of hyperactivity, magnetic field effects on the circadian clock, and hypomagnetic field effects on neurogenesis and microtubule assembly. We conclude by discussing future lines of investigation in this exciting new area of quantum biology.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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5
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Schwinn K, Ferré N, Huix-Rotllant M. UV-visible absorption spectrum of FAD and its reduced forms embedded in a cryptochrome protein. Phys Chem Chem Phys 2020; 22:12447-12455. [PMID: 32458897 DOI: 10.1039/d0cp01714k] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cryptochromes are a class of flavoproteins proposed as candidates to explain magnetoreception of animals, plants and bacteria. The main hypothesis is that a biradical is formed upon blue-light absorption by flavin adenine dinucleotide (FAD). In a protein milieu, the oxidized form of FAD can be reduced, leading to four redox derivative forms: anionic and neutral semi-reduced radicals, and anionic and neutral fully reduced forms. All these forms have a characteristic electronic absorption spectrum, with a strong vibrational resolution. Here, we carried out a normal mode analysis at the electrostatic embedding QM/MM level of theory to compute the vibrationally resolved absorption spectra of the five redox forms of FAD embedded in a plant cryptochrome. We show that explicitly accounting for vibrational broadening contributions to electronic transitions is essential to reproduce the experimental spectra. In the case of the neutral radical form of FAD, the absorption spectrum is reproduced only if the presence of a tryptophan radical is considered.
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6
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Margiotta JF, Howard MJ. Cryptochromes Mediate Intrinsic Photomechanical Transduction in Avian Iris and Somatic Striated Muscle. Front Physiol 2020; 11:128. [PMID: 32153427 PMCID: PMC7047837 DOI: 10.3389/fphys.2020.00128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/06/2020] [Indexed: 01/12/2023] Open
Abstract
Irises isolated from the eyes of diverse species constrict when exposed to light. Depending on species this intrinsic photomechanical transduction response (PMTR) requires either melanopsin or cryptochrome (CRY) photopigment proteins, generated by their respective association with retinoid or flavin adenine dinucleotide (FAD) chromophores. Although developmentally relevant circadian rhythms are also synchronized and reset by these same proteins, the cell type, mechanism, and specificity of photomechanical transduction (PMT) and its relationship to circadian processes remain poorly understood. Here we show that PMTRs consistent with CRY activation by 430 nm blue light occur in developing chicken iris striated muscle, identify relevant mechanisms, and demonstrate that similar PMTRs occur in striated iris and pectoral muscle fibers, prevented in both cases by knocking down CRY gene transcript levels. Supporting CRY activation, iris PMTRs were reduced by inhibiting flavin reductase, but unaffected by melanopsin antagonism. The largest iris PMTRs paralleled the developmental predominance of striated over smooth muscle fibers, and shared their requirement for extracellular Ca2+ influx and release of intracellular Ca2+. Photo-stimulation of identified striated myotubes maintained in dissociated culture revealed the cellular and molecular bases of PMT. Myotubes in iris cell cultures responded to 435 nm light with increased intracellular Ca2+ and contractions, mimicking iris PMTRs and their spectral sensitivity. Interestingly PMTRs featuring contractions and requiring extracellular Ca2+ influx and release of intracellular Ca2+ were also displayed by striated myotubes derived from pectoral muscle. Consistent with these findings, cytosolic CRY1 and CRY2 proteins were detected in both iris and pectoral myotubes, and knocking down myotube CRY1/CRY2 gene transcript levels specifically blocked PMTRs in both cases. Thus CRY-mediated PMT is not unique to iris, but instead reflects a more general feature of developing striated muscle fibers. Because CRYs are core timing components of circadian clocks and CRY2 is critical for circadian regulation of myogenic differentiation CRY-mediated PMT may interact with cell autonomous clocks to influence the progression of striated muscle development.
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Affiliation(s)
- Joseph F Margiotta
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Marthe J Howard
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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7
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Player TC, Hore PJ. Viability of superoxide-containing radical pairs as magnetoreceptors. J Chem Phys 2020; 151:225101. [PMID: 31837685 DOI: 10.1063/1.5129608] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The ability of night-migratory songbirds to sense the direction of the Earth's magnetic field is increasingly attributed to a photochemical mechanism in which the magnetic field acts on transient radical pairs in cryptochrome flavoproteins located in the birds' eyes. The magnetically sensitive species is commonly assumed to be [FAD•- TrpH•+], formed by sequential light-induced intraprotein electron transfers from a chain of tryptophan residues to the flavin adenine dinucleotide chromophore. However, some evidence points to superoxide, O2 •-, as an alternative partner for the flavin radical. The absence of hyperfine interactions in O2 •- could lead to a more sensitive magnetic compass, but only if the electron spin relaxation of the O2 •- radical is much slower than normally expected for a small mobile radical with an orbitally degenerate electronic ground state. In this study we use spin dynamics simulations to model the sensitivity of a flavin-superoxide radical pair to the direction of a 50 μT magnetic field. By varying parameters that characterize the local environment and molecular dynamics of the radicals, we identify the highly restrictive conditions under which a O2 •--containing radical pair could form the basis of a geomagnetic compass sensor. We conclude that the involvement of superoxide in compass magnetoreception must remain highly speculative until further experimental evidence is forthcoming.
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Affiliation(s)
- Thomas C Player
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - P J Hore
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
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8
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Mondal P, Huix-Rotllant M. Theoretical insights into the formation and stability of radical oxygen species in cryptochromes. Phys Chem Chem Phys 2019; 21:8874-8882. [PMID: 30977757 DOI: 10.1039/c9cp00782b] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cryptochrome is a blue-light absorbing flavoprotein containing a flavin adenine dinucleotide (FAD) cofactor. FAD can accept up to two electrons and two protons, which can be subsequently transferred to substrates present in the binding pocket. It is well known that reactive oxygen species are generated when triplet molecular oxygen is present in the cavity. Here, we investigate the formation and stability of radical oxygen species in Drosophila melanogaster cryptochrome using molecular dynamics simulations and electronic structure calculations. We find that the superoxide and hydroxyl radicals in doublet spin states are stabilized in the pocket due to the attractive electrostatic interactions and hydrogen bonding with partially reduced FAD. These findings validate from a molecular dynamics perspective that [FAD˙--HO2˙] or [FADH˙-O2˙-] can be alternative radical pairs at the origin of magnetoreception.
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9
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Zoltowski BD, Chelliah Y, Wickramaratne A, Jarocha L, Karki N, Xu W, Mouritsen H, Hore PJ, Hibbs RE, Green CB, Takahashi JS. Chemical and structural analysis of a photoactive vertebrate cryptochrome from pigeon. Proc Natl Acad Sci U S A 2019; 116:19449-19457. [PMID: 31484780 PMCID: PMC6765304 DOI: 10.1073/pnas.1907875116] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Computational and biochemical studies implicate the blue-light sensor cryptochrome (CRY) as an endogenous light-dependent magnetosensor enabling migratory birds to navigate using the Earth's magnetic field. Validation of such a mechanism has been hampered by the absence of structures of vertebrate CRYs that have functional photochemistry. Here we present crystal structures of Columba livia (pigeon) CRY4 that reveal evolutionarily conserved modifications to a sequence of Trp residues (Trp-triad) required for CRY photoreduction. In ClCRY4, the Trp-triad chain is extended to include a fourth Trp (W369) and a Tyr (Y319) residue at the protein surface that imparts an unusually high quantum yield of photoreduction. These results are consistent with observations of night migratory behavior in animals at low light levels and could have implications for photochemical pathways allowing magnetosensing.
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Affiliation(s)
- Brian D Zoltowski
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275
- Center for Drug Discovery, Design, and Delivery, Southern Methodist University, Dallas, TX 75275
| | - Yogarany Chelliah
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Anushka Wickramaratne
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Lauren Jarocha
- Department of Chemistry, University of Oxford, OX1 3QZ Oxford, United Kingdom
| | - Nischal Karki
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275
- Center for Drug Discovery, Design, and Delivery, Southern Methodist University, Dallas, TX 75275
| | - Wei Xu
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University of Oldenburg, DE-26111 Oldenburg, Germany
- Research Center for Neurosensory Sciences, University of Oldenburg, DE-26111 Oldenburg, Germany
| | - Peter J Hore
- Department of Chemistry, University of Oxford, OX1 3QZ Oxford, United Kingdom
| | - Ryan E Hibbs
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Carla B Green
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Joseph S Takahashi
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390;
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
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10
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Kar RK, Borin VA, Ding Y, Matysik J, Schapiro I. Spectroscopic Properties of Lumiflavin: A Quantum Chemical Study. Photochem Photobiol 2018; 95:662-674. [DOI: 10.1111/php.13023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/05/2018] [Indexed: 12/24/2022]
Affiliation(s)
- Rajiv Kumar Kar
- Fritz Haber Center for Molecular Dynamics Research Institute of Chemistry Hebrew University of Jerusalem Jerusalem Israel
| | - Veniamin A. Borin
- Fritz Haber Center for Molecular Dynamics Research Institute of Chemistry Hebrew University of Jerusalem Jerusalem Israel
| | - Yonghong Ding
- Institute of Analytical Chemistry University of Leipzig Leipzig Germany
| | - Jörg Matysik
- Institute of Analytical Chemistry University of Leipzig Leipzig Germany
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics Research Institute of Chemistry Hebrew University of Jerusalem Jerusalem Israel
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11
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Sherrard RM, Morellini N, Jourdan N, El-Esawi M, Arthaut LD, Niessner C, Rouyer F, Klarsfeld A, Doulazmi M, Witczak J, d’Harlingue A, Mariani J, Mclure I, Martino CF, Ahmad M. Low-intensity electromagnetic fields induce human cryptochrome to modulate intracellular reactive oxygen species. PLoS Biol 2018; 16:e2006229. [PMID: 30278045 PMCID: PMC6168118 DOI: 10.1371/journal.pbio.2006229] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/29/2018] [Indexed: 12/11/2022] Open
Abstract
Exposure to man-made electromagnetic fields (EMFs), which increasingly pollute our environment, have consequences for human health about which there is continuing ignorance and debate. Whereas there is considerable ongoing concern about their harmful effects, magnetic fields are at the same time being applied as therapeutic tools in regenerative medicine, oncology, orthopedics, and neurology. This paradox cannot be resolved until the cellular mechanisms underlying such effects are identified. Here, we show by biochemical and imaging experiments that exposure of mammalian cells to weak pulsed electromagnetic fields (PEMFs) stimulates rapid accumulation of reactive oxygen species (ROS), a potentially toxic metabolite with multiple roles in stress response and cellular ageing. Following exposure to PEMF, cell growth is slowed, and ROS-responsive genes are induced. These effects require the presence of cryptochrome, a putative magnetosensor that synthesizes ROS. We conclude that modulation of intracellular ROS via cryptochromes represents a general response to weak EMFs, which can account for either therapeutic or pathological effects depending on exposure. Clinically, our findings provide a rationale to optimize low field magnetic stimulation for novel therapeutic applications while warning against the possibility of harmful synergistic effects with environmental agents that further increase intracellular ROS. Repetitive low-intensity magnetic stimulation has been used in the treatment of disease for over 50 years. Associated benefits have included alleviation of depression, memory loss, and symptoms of Parkinson disease, as well as accelerated bone and wound healing and the treatment of certain cancers, independently of surgery or drugs. However, the cellular mechanisms underlying these effects remain unclear. Here, we demonstrate that repetitive magnetic field exposure in human cells stimulates production of biological stress response chemicals known as reactive oxygen species (ROS). At moderate doses, we find that reactive oxygen actively stimulates cellular repair and stress response pathways, which might account for the observed therapeutic effects to repetitive magnetic stimulation. We further show that this response requires the function of a well-characterized, evolutionarily conserved flavoprotein receptor known as cryptochrome, which has been implicated in magnetic sensing in organisms ranging from plants to flies, including migratory birds. We conclude that exposure to weak magnetic fields induces the production of ROS in human cells and that this process requires the presence of the cryptochrome receptor.
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Affiliation(s)
- Rachel M. Sherrard
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Team Repairing Neural Networks, Paris, France
| | - Natalie Morellini
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Team Repairing Neural Networks, Paris, France
| | - Nathalie Jourdan
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
| | - Mohamed El-Esawi
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
- Botany Department, Faculty of Science, Tanta University, Tanta, Egypt
| | - Louis-David Arthaut
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
| | - Christine Niessner
- Department of Earth and Environmental Sciences, Ludwig-Maximillians-Universität Munich, Theresienstraße, Munich, Germany
| | - Francois Rouyer
- Institut des Neurosciences Paris-Saclay, Université Paris Sud, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Andre Klarsfeld
- Brain Plasticity Unit, UMR 8249 (ESPCI Paris/CNRS), PSL Research University, Paris, France
| | - Mohamed Doulazmi
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Team Repairing Neural Networks, Paris, France
| | - Jacques Witczak
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
| | - Alain d’Harlingue
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
| | - Jean Mariani
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Team Repairing Neural Networks, Paris, France
| | - Ian Mclure
- Department of Biomedical Engineering, Florida Institute of Technology, Melbourne, Florida, United States of America
| | - Carlos F. Martino
- Department of Biomedical Engineering, Florida Institute of Technology, Melbourne, Florida, United States of America
| | - Margaret Ahmad
- Sorbonne Université, CNRS Unit Biological Adaptation and Ageing, Photobiology Team, Paris, France
- Xavier University, Cincinnati, Ohio, United States of America
- * E-mail:
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12
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Hong G, Pachter R, Ritz T. Coupling Drosophila melanogaster Cryptochrome Light Activation and Oxidation of the Kvβ Subunit Hyperkinetic NADPH Cofactor. J Phys Chem B 2018; 122:6503-6510. [PMID: 29847128 DOI: 10.1021/acs.jpcb.8b03493] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Motivated by the observations on the involvement of light-induced processes in the Drosophila melanogaster cryptochrome (DmCry) in regulation of the neuronal firing rate, which is achieved by a redox-state change of its voltage-dependent K+ channel Kvβ subunit hyperkinetic (Hk) reduced nicotinamide adenine dinucleotide phosphate (NADPH) cofactor, we propose in this work two hypothetical pathways that may potentially enable such coupling. In the first pathway, triggered by blue-light-induced formation of a radical pair [FAD•-TRP•+] in DmCry, the hole (TRP•+) may hop to Hk, for example, through a tryptophan chain and oxidize NADPH, possibly leading to inhibition of the N-terminus inactivation in the K+ channel. In a second possible pathway, DmCry's FAD•- is reoxidized by molecular oxygen, producing H2O2, which then diffuses to Hk and oxidizes NADPH. In this work, by applying a combination of quantum and empirical-based methods for free-energy calculations, we find that the oxidation of NADPH by TRP•+ or H2O2 and the reoxidation of FAD•- by O2 are thermodynamically feasible. Our results may have an implication in identifying a magnetic sensing signal transduction pathway, specifically upon Drosophila's Hk NADPH cofactor oxidation, with a subsequent inhibition of the K+ channel N-terminus inactivation gate, permitting K+ flux.
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Affiliation(s)
- Gongyi Hong
- Air Force Research Laboratory , Wright-Patterson Air Force Base , Dayton , Ohio 45433-7702 , United States
| | - Ruth Pachter
- Air Force Research Laboratory , Wright-Patterson Air Force Base , Dayton , Ohio 45433-7702 , United States
| | - Thorsten Ritz
- Department of Physics and Astronomy , University of California , Irvine , California 92697-4575 , United States
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Kattnig DR. Radical-Pair-Based Magnetoreception Amplified by Radical Scavenging: Resilience to Spin Relaxation. J Phys Chem B 2017; 121:10215-10227. [DOI: 10.1021/acs.jpcb.7b07672] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Daniel R. Kattnig
- Living Systems Institute
and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, United Kingdom
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Arthaut LD, Jourdan N, Mteyrek A, Procopio M, El-Esawi M, d’Harlingue A, Bouchet PE, Witczak J, Ritz T, Klarsfeld A, Birman S, Usselman RJ, Hoecker U, Martino CF, Ahmad M. Blue-light induced accumulation of reactive oxygen species is a consequence of the Drosophila cryptochrome photocycle. PLoS One 2017; 12:e0171836. [PMID: 28296892 PMCID: PMC5351967 DOI: 10.1371/journal.pone.0171836] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/26/2017] [Indexed: 01/03/2023] Open
Abstract
Cryptochromes are evolutionarily conserved blue-light absorbing flavoproteins which participate in many important cellular processes including in entrainment of the circadian clock in plants, Drosophila and humans. Drosophila melanogaster cryptochrome (DmCry) absorbs light through a flavin (FAD) cofactor that undergoes photoreduction to the anionic radical (FAD•-) redox state both in vitro and in vivo. However, recent efforts to link this photoconversion to the initiation of a biological response have remained controversial. Here, we show by kinetic modeling of the DmCry photocycle that the fluence dependence, quantum yield, and half-life of flavin redox state interconversion are consistent with the anionic radical (FAD•-) as the signaling state in vivo. We show by fluorescence detection techniques that illumination of purified DmCry results in enzymatic conversion of molecular oxygen (O2) to reactive oxygen species (ROS). We extend these observations in living cells to demonstrate transient formation of superoxide (O2•-), and accumulation of hydrogen peroxide (H2O2) in the nucleus of insect cell cultures upon DmCry illumination. These results define the kinetic parameters of the Drosophila cryptochrome photocycle and support light-driven electron transfer to the flavin in DmCry signaling. They furthermore raise the intriguing possibility that light-dependent formation of ROS as a byproduct of the cryptochrome photocycle may contribute to its signaling role.
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Affiliation(s)
- Louis-David Arthaut
- UMR CNRS 8256 (B2A), IBPS, Université Paris VI, Paris, France
- Department of Biomedical Engineering, Florida Institute of Technology, Melbourne, Florida, United States of America
| | | | - Ali Mteyrek
- GCRN team, Brain Plasticity Unit, UMR 8249 CNRS/ESPCI Paris, PSL Research University, Paris, France
| | - Maria Procopio
- UMR CNRS 8256 (B2A), IBPS, Université Paris VI, Paris, France
- Department of Physics and Astronomy, University of California, Irvine, California, United States of America
| | - Mohamed El-Esawi
- UMR CNRS 8256 (B2A), IBPS, Université Paris VI, Paris, France
- Botany Department, Faculty of Science, Tanta University, Tanta, Egypt
| | | | | | - Jacques Witczak
- UMR CNRS 8256 (B2A), IBPS, Université Paris VI, Paris, France
| | - Thorsten Ritz
- Department of Physics and Astronomy, University of California, Irvine, California, United States of America
| | - André Klarsfeld
- GCRN team, Brain Plasticity Unit, UMR 8249 CNRS/ESPCI Paris, PSL Research University, Paris, France
| | - Serge Birman
- GCRN team, Brain Plasticity Unit, UMR 8249 CNRS/ESPCI Paris, PSL Research University, Paris, France
| | - Robert J. Usselman
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Ute Hoecker
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Cologne, Germany
| | - Carlos F. Martino
- Department of Biomedical Engineering, Florida Institute of Technology, Melbourne, Florida, United States of America
| | - Margaret Ahmad
- UMR CNRS 8256 (B2A), IBPS, Université Paris VI, Paris, France
- Department of Biology, Xavier University, Cincinnati, Ohio, United States of America
- * E-mail:
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Ahmad M. Photocycle and signaling mechanisms of plant cryptochromes. CURRENT OPINION IN PLANT BIOLOGY 2016; 33:108-115. [PMID: 27423124 DOI: 10.1016/j.pbi.2016.06.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/14/2016] [Accepted: 06/17/2016] [Indexed: 05/20/2023]
Abstract
Cryptochromes are flavoprotein blue light receptors that control many aspects of plant growth and development including seedling de-etiolation, elongation growth, the initiation of flowering, and entrainment of the circadian clock. Photon absorption by Arabidopsis cryptochromes cry1 and cry2 initiates electron transfer to the oxidized flavin cofactor (FADox) and formation of the presumed biological signaling state FADH°. Current literature on the nature and formation of the signaling state is reviewed, and potential novel roles for cryptochromes in oxidative stress and as magnetosensors are discussed in light of the cryptochrome photocycle.
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Affiliation(s)
- Margaret Ahmad
- UMR 8256B B2A, IBPS, Casier 156, Université Pierre et Marie Curie, 7 Quai St. Bernard, 75005 Paris, France; Xavier University, 3800 Victory Parkway, Cincinnati, OH 45207, USA.
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Affiliation(s)
- P. J. Hore
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität Oldenburg, DE-26111 Oldenburg, Germany;
- Research Centre for Neurosensory Sciences, University of Oldenburg, DE-26111 Oldenburg, Germany
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