1
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Brodrick E, Jékely G. Photobehaviours guided by simple photoreceptor systems. Anim Cogn 2023; 26:1817-1835. [PMID: 37650997 PMCID: PMC10770211 DOI: 10.1007/s10071-023-01818-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/29/2023] [Accepted: 08/01/2023] [Indexed: 09/01/2023]
Abstract
Light provides a widely abundant energy source and valuable sensory cue in nature. Most animals exposed to light have photoreceptor cells and in addition to eyes, there are many extraocular strategies for light sensing. Here, we review how these simpler forms of detecting light can mediate rapid behavioural responses in animals. Examples of these behaviours include photophobic (light avoidance) or scotophobic (shadow) responses, photokinesis, phototaxis and wavelength discrimination. We review the cells and response mechanisms in these forms of elementary light detection, focusing on aquatic invertebrates with some protist and terrestrial examples to illustrate the general principles. Light cues can be used very efficiently by these simple photosensitive systems to effectively guide animal behaviours without investment in complex and energetically expensive visual structures.
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Affiliation(s)
- Emelie Brodrick
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Centre for Organismal Studies, University of Heidelberg, 69120, Heidelberg, Germany
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2
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Arévalo-López C, Gleitze S, Madariaga S, Plaza-Rosales I. Pupillary response to chromatic light stimuli as a possible biomarker at the early stage of glaucoma: a review. Int Ophthalmol 2023; 43:343-356. [PMID: 35781599 DOI: 10.1007/s10792-022-02381-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 06/14/2022] [Indexed: 02/07/2023]
Abstract
Glaucoma is a multifactorial neurodegenerative disease of the optic nerve currently considered a severe health problem because of its high prevalence, being the primary cause of irreversible blindness worldwide. The most common type corresponds to Primary Open-Angle Glaucoma. Glaucoma produces, among other alterations, a progressive loss of retinal ganglion cells (RGC) and its axons which are the key contributors to generate action potentials that reach the visual cortex to create the visual image. Glaucoma is characterized by Visual Field loss whose main feature is to be painless and therefore makes early detection difficult, causing a late diagnosis and a delayed treatment indication that slows down its progression. Intrinsically photosensitive retinal ganglion cells, which represent a subgroup of RGCs are characterized by their response to short-wave light stimulation close to 480 nm, their non-visual function, and their role in the generation of the pupillary reflex. Currently, the sensitivity of clinical examinations correlates to RGC damage; however, the need for an early damage biomarker is still relevant. It is an urgent task to create new diagnostic approaches to detect an early stage of glaucoma in a prompt, quick, and economical manner. We summarize the pathology of glaucoma and its current clinical detection methods, and we suggest evaluating the pupillary response to chromatic light as a potential biomarker of disease, due to its diagnostic benefit and its cost-effectiveness in clinical practice in order to reduce irreversible damage caused by glaucoma.
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Affiliation(s)
- Carla Arévalo-López
- Department of Medical Technology, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Silvia Gleitze
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Samuel Madariaga
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Laboratorio de Neurosistemas, Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Ecological Cognitive Neuroscience Group, Santiago, Chile
| | - Iván Plaza-Rosales
- Department of Medical Technology, Faculty of Medicine, Universidad de Chile, Santiago, Chile. .,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile. .,Laboratorio de Neurosistemas, Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile. .,Ecological Cognitive Neuroscience Group, Santiago, Chile.
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3
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Guo X, Wang H, Xu J, Hua H. Impacts of vitamin A deficiency on biological rhythms: Insights from the literature. Front Nutr 2022; 9:886244. [PMID: 36466383 PMCID: PMC9718491 DOI: 10.3389/fnut.2022.886244] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 11/02/2022] [Indexed: 03/21/2024] Open
Abstract
Vitamin A is essential for brain function, in addition to its important roles in vision, immunity, and reproduction. Previous studies have shown that retinoic acid (RA), the bioactive form of vitamin A, is involved in the regulation of various intracellular responses related to biological rhythms. RA is reported to affect the circadian rhythm by binding to RA receptors, such as receptors in the circadian feedback loops in the mammalian suprachiasmatic nucleus. However, evidence of the impacts of vitamin A deficiency (VAD) on biological rhythms is limited, and most of the related studies were conducted on animals. In this review, we described the physiological functions of biological rhythms and physiological pathways/molecular mechanisms regulating the biological rhythms. We then discussed the current understanding of the associations of VAD with biological rhythm disorders/diseases (sleep disorders, impairments in learning/memory, emotional disorders, and other immune or metabolism diseases) and summarized the currently proposed mechanisms (mainly by retinoid nuclear receptors and related proteins) for the associations. This review may help recognize the role of VAD in biological rhythm disorders and stimulate clinical or epidemiological studies to confirm the findings of related animal studies.
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Affiliation(s)
- Xiangrong Guo
- Shanghai Key Laboratory of Embryo Original Diseases, The International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hui Wang
- MOE-Shanghai Key Lab of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Xu
- Shanghai Key Laboratory of Embryo Original Diseases, The International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hui Hua
- Shanghai Key Laboratory of Embryo Original Diseases, The International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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4
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Argilés M, Sunyer-Grau B, Arteche-Fernandez S, Peña-Gómez C. Functional connectivity of brain networks with three monochromatic wavelengths: a pilot study using resting-state functional magnetic resonance imaging. Sci Rep 2022; 12:16197. [PMID: 36171254 PMCID: PMC9519584 DOI: 10.1038/s41598-022-20668-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 09/16/2022] [Indexed: 11/28/2022] Open
Abstract
Exposure to certain monochromatic wavelengths can affect non-visual brain regions. Growing research indicates that exposure to light can have a positive impact on health-related problems such as spring asthenia, circadian rhythm disruption, and even bipolar disorders and Alzheimer’s. However, the extent and location of changes in brain areas caused by exposure to monochromatic light remain largely unknown. This pilot study (N = 7) using resting-state functional magnetic resonance shows light-dependent functional connectivity patterns on brain networks. We demonstrated that 1 min of blue, green, or red light exposure modifies the functional connectivity (FC) of a broad range of visual and non-visual brain regions. Largely, we observed: (i) a global decrease in FC in all the networks but the salience network after blue light exposure, (ii) a global increase in FC after green light exposure, particularly noticeable in the left hemisphere, and (iii) a decrease in FC on attentional networks coupled with a FC increase in the default mode network after red light exposure. Each one of the FC patterns appears to be best arranged to perform better on tasks associated with specific cognitive domains. Results can be relevant for future research on the impact of light stimulation on brain function and in a variety of health disciplines.
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Affiliation(s)
- Marc Argilés
- School of Optics and Optometry, Universitat Politècnica de Catalunya, Terrassa, Catalonia, Spain.
| | - Bernat Sunyer-Grau
- School of Optics and Optometry, Universitat Politècnica de Catalunya, Terrassa, Catalonia, Spain
| | - Sílvia Arteche-Fernandez
- School of Optics and Optometry, Universitat Politècnica de Catalunya, Terrassa, Catalonia, Spain
| | - Cleofé Peña-Gómez
- BarcelonaBeta Brain Research Center (BBRC), Pasqual Maragall Foundation, Barcelona, Catalonia, Spain
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5
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Feng Z, Ducos B, Scerbo P, Aujard I, Jullien L, Bensimon D. The Development and Application of Opto-Chemical Tools in the Zebrafish. Molecules 2022; 27:6231. [PMID: 36234767 PMCID: PMC9572478 DOI: 10.3390/molecules27196231] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 11/18/2022] Open
Abstract
The zebrafish is one of the most widely adopted animal models in both basic and translational research. This popularity of the zebrafish results from several advantages such as a high degree of similarity to the human genome, the ease of genetic and chemical perturbations, external fertilization with high fecundity, transparent and fast-developing embryos, and relatively low cost-effective maintenance. In particular, body translucency is a unique feature of zebrafish that is not adequately obtained with other vertebrate organisms. The animal's distinctive optical clarity and small size therefore make it a successful model for optical modulation and observation. Furthermore, the convenience of microinjection and high embryonic permeability readily allow for efficient delivery of large and small molecules into live animals. Finally, the numerous number of siblings obtained from a single pair of animals offers large replicates and improved statistical analysis of the results. In this review, we describe the development of opto-chemical tools based on various strategies that control biological activities with unprecedented spatiotemporal resolution. We also discuss the reported applications of these tools in zebrafish and highlight the current challenges and future possibilities of opto-chemical approaches, particularly at the single cell level.
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Affiliation(s)
- Zhiping Feng
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Bertrand Ducos
- Laboratoire de Physique de l’Ecole Normale Supérieure, Paris Sciences Letters University, Sorbonne Université, Université de Paris, Centre National de la Recherche Scientifique, 24 Rue Lhomond, 75005 Paris, France
- High Throughput qPCR Core Facility, Ecole Normale Supérieure, Paris Sciences Letters University, 46 Rue d’Ulm, 75005 Paris, France
| | - Pierluigi Scerbo
- Laboratoire de Physique de l’Ecole Normale Supérieure, Paris Sciences Letters University, Sorbonne Université, Université de Paris, Centre National de la Recherche Scientifique, 24 Rue Lhomond, 75005 Paris, France
- Inovarion, 75005 Paris, France
| | - Isabelle Aujard
- Laboratoire PASTEUR, Département de Chimie, Ecole Normale Supérieure, Paris Sciences Letters University, Sorbonne Université, Centre National de la Recherche Scientifique, 24 Rue Lhomond, 75005 Paris, France
| | - Ludovic Jullien
- Laboratoire PASTEUR, Département de Chimie, Ecole Normale Supérieure, Paris Sciences Letters University, Sorbonne Université, Centre National de la Recherche Scientifique, 24 Rue Lhomond, 75005 Paris, France
| | - David Bensimon
- Laboratoire de Physique de l’Ecole Normale Supérieure, Paris Sciences Letters University, Sorbonne Université, Université de Paris, Centre National de la Recherche Scientifique, 24 Rue Lhomond, 75005 Paris, France
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
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6
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Chambers S, Leftwich T, Pamonag M, Rice J, Walker MT. Trpm1: Novel function at the intersection of light and pain response in the iris. Exp Eye Res 2021; 215:108897. [PMID: 34954202 DOI: 10.1016/j.exer.2021.108897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/06/2021] [Accepted: 12/09/2021] [Indexed: 11/16/2022]
Abstract
In mammals, the retina is the photosensitive tissue that is responsible for the capture of light and the transduction of the light-initiated signals to the brain. These visual signals help to drive image and non-image forming behaviors. The pupillary light reflex (PLR) is an involuntary non-image forming behavior which involves the constriction of the iris muscle tissue in response to ambient light intensity. A subset of photosensitive retinal ganglion cells provides the principal pathway for all light input to the olivary pretectal nucleus which directs the neuronal input to drive iris constriction. Transient receptor potential melastatin 1 (Trpm1) knockout mice have a severe defect in PLR, but it remains unclear how the Trpm1 channel contributes to this behavior. We have demonstrated that the reduced PLR in Trpm1-/- mice at scotopic and photopic intensities is due to a functional loss of Trpm1 in the retina as well as the iris sphincter muscle. We have also tested constriction in isolated eyes and have shown that light-driven constriction independent of signaling from the brain also requires Trpm1 expression. In both the in vivo PLR and the iris photomechanical response, melanopsin is required for the light-dependent activation. Finally, pharmacological experiments using capsaicin to activate pain afferents in the eye demonstrate that Trpm1 expression is required for all sensory driven iris constriction. Our results demonstrate for the first time that Trpm1 has a novel and necessary role in iridial cells and is required for all sensory-driven constriction in the iris.
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Affiliation(s)
- Shane Chambers
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Tess Leftwich
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Michael Pamonag
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Jeremy Rice
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Marquis T Walker
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA.
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7
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Fasick JI, Algrain H, Samuels C, Mahadevan P, Schweikert LE, Naffaa ZJ, Robinson PR. Spectral tuning and deactivation kinetics of marine mammal melanopsins. PLoS One 2021; 16:e0257436. [PMID: 34653198 PMCID: PMC8519484 DOI: 10.1371/journal.pone.0257436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/31/2021] [Indexed: 02/04/2023] Open
Abstract
In mammals, the photopigment melanopsin (Opn4) is found in a subset of retinal ganglion cells that serve light detection for circadian photoentrainment and pupil constriction (i.e., mydriasis). For a given species, the efficiency of photoentrainment and length of time that mydriasis occurs is determined by the spectral sensitivity and deactivation kinetics of melanopsin, respectively, and to date, neither of these properties have been described in marine mammals. Previous work has indicated that the absorbance maxima (λmax) of marine mammal rhodopsins (Rh1) have diversified to match the available light spectra at foraging depths. However, similar to the melanopsin λmax of terrestrial mammals (~480 nm), the melanopsins of marine mammals may be conserved, with λmax values tuned to the spectrum of solar irradiance at the water's surface. Here, we investigated the Opn4 pigments of 17 marine mammal species inhabiting diverse photic environments including the Infraorder Cetacea, as well as the Orders Sirenia and Carnivora. Both genomic and cDNA sequences were used to deduce amino acid sequences to identify substitutions most likely involved in spectral tuning and deactivation kinetics of the Opn4 pigments. Our results show that there appears to be no amino acid substitutions in marine mammal Opn4 opsins that would result in any significant change in λmax values relative to their terrestrial counterparts. We also found some marine mammal species to lack several phosphorylation sites in the carboxyl terminal domain of their Opn4 pigments that result in significantly slower deactivation kinetics, and thus longer mydriasis, compared to terrestrial controls. This finding was restricted to cetacean species previously found to lack cone photoreceptor opsins, a condition known as rod monochromacy. These results suggest that the rod monochromat whales rely on extended pupillary constriction to prevent photobleaching of the highly photosensitive all-rod retina when moving between photopic and scotopic conditions.
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Affiliation(s)
- Jeffry I. Fasick
- Department of Biological Sciences, The University of Tampa, Tampa, Florida, United States of America
| | - Haya Algrain
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| | - Courtland Samuels
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Padmanabhan Mahadevan
- Department of Biological Sciences, The University of Tampa, Tampa, Florida, United States of America
| | - Lorian E. Schweikert
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America
| | - Zaid J. Naffaa
- Department of Biological Sciences, Kean University, Union, New Jersey, United States of America
| | - Phyllis R. Robinson
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
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8
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Van Gelder RN. Gene Therapy Approaches to Slow or Reverse Blindness From Inherited Retinal Degeneration: Growth Factors and Optogenetics. Int Ophthalmol Clin 2021; 61:209-228. [PMID: 34584058 PMCID: PMC8486303 DOI: 10.1097/iio.0000000000000386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To date, clinical gene therapy efforts for inherited retinal degeneration (IRD) have focused largely on gene replacement. The large number of genes and alleles causing IRD, however, makes this approach practical only for the most common causes. Additionally, gene replacement therapy cannot reverse existing retinal degeneration. Viral-mediated gene therapy can be used for two other approaches to slow or reverse IRD. First, by driving intraocular expression of growth factors or neuroprotective proteins, retinal degeneration can be slowed. Second, by expressing light-sensitive proteins (either microbial channelopsins or mammalian G-protein coupled opsins) in preserved inner retinal neurons, light sensitivity can be restored to the blind retina. Both approaches have advanced substantially in the past decade, and both are nearing clinical tests. This review surveys recent progress in these approaches.
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9
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Abstract
The increasing prevalence of myopia is a significant public health concern. Unfortunately, the mechanisms driving myopia remain elusive, limiting effective treatment options. This report identifies a refractive development pathway that requires Opn5-expressing retinal ganglion cells (RGCs). Stimulation of Opn5 RGCs with short-wavelength violet light prevented experimental myopia in mice. Furthermore, this effect was dependent on the time of day, with evening exposure being sufficient to protect against experimental myopia. Thus, these studies suggest Opn5 RGCs may contribute to the mechanisms of emmetropization and identify the OPN5 pathway as a potential target for the treatment of myopia. Myopia has become a major public health concern, particularly across much of Asia. It has been shown in multiple studies that outdoor activity has a protective effect on myopia. Recent reports have shown that short-wavelength visible violet light is the component of sunlight that appears to play an important role in preventing myopia progression in mice, chicks, and humans. The mechanism underlying this effect has not been understood. Here, we show that violet light prevents lens defocus–induced myopia in mice. This violet light effect was dependent on both time of day and retinal expression of the violet light sensitive atypical opsin, neuropsin (OPN5). These findings identify Opn5-expressing retinal ganglion cells as crucial for emmetropization in mice and suggest a strategy for myopia prevention in humans.
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10
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Kleinlogel S, Vogl C, Jeschke M, Neef J, Moser T. Emerging approaches for restoration of hearing and vision. Physiol Rev 2020; 100:1467-1525. [DOI: 10.1152/physrev.00035.2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Impairments of vision and hearing are highly prevalent conditions limiting the quality of life and presenting a major socioeconomic burden. For long, retinal and cochlear disorders have remained intractable for causal therapies, with sensory rehabilitation limited to glasses, hearing aids, and electrical cochlear or retinal implants. Recently, the application of gene therapy and optogenetics to eye and ear has generated hope for a fundamental improvement of vision and hearing restoration. To date, one gene therapy for the restoration of vision has been approved and undergoing clinical trials will broaden its application including gene replacement, genome editing, and regenerative approaches. Moreover, optogenetics, i.e. controlling the activity of cells by light, offers a more general alternative strategy. Over little more than a decade, optogenetic approaches have been developed and applied to better understand the function of biological systems, while protein engineers have identified and designed new opsin variants with desired physiological features. Considering potential clinical applications of optogenetics, the spotlight is on the sensory systems. Multiple efforts have been undertaken to restore lost or hampered function in eye and ear. Optogenetic stimulation promises to overcome fundamental shortcomings of electrical stimulation, namely poor spatial resolution and cellular specificity, and accordingly to deliver more detailed sensory information. This review aims at providing a comprehensive reference on current gene therapeutic and optogenetic research relevant to the restoration of hearing and vision. We will introduce gene-therapeutic approaches and discuss the biotechnological and optoelectronic aspects of optogenetic hearing and vision restoration.
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Affiliation(s)
| | | | | | | | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Germany
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11
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Kusumoto J, Takeo M, Hashikawa K, Komori T, Tsuji T, Terashi H, Sakakibara S. OPN4 belongs to the photosensitive system of the human skin. Genes Cells 2020; 25:215-225. [DOI: 10.1111/gtc.12751] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/18/2020] [Accepted: 01/21/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Junya Kusumoto
- Department of Plastic Surgery Kobe University Graduate School of Medicine Kobe Japan
- Department of Oral and Maxillofacial Surgery Kobe University Graduate School of Medicine Kobe Japan
| | - Makoto Takeo
- Laboratory for Organ Regeneration RIKEN Center for Biosystems Dynamics Research Kobe Japan
| | - Kazunobu Hashikawa
- Department of Plastic Surgery Kobe University Graduate School of Medicine Kobe Japan
| | - Takahide Komori
- Department of Oral and Maxillofacial Surgery Kobe University Graduate School of Medicine Kobe Japan
| | - Takashi Tsuji
- Laboratory for Organ Regeneration RIKEN Center for Biosystems Dynamics Research Kobe Japan
| | - Hiroto Terashi
- Department of Plastic Surgery Kobe University Graduate School of Medicine Kobe Japan
| | - Shunsuke Sakakibara
- Department of Plastic Surgery Kobe University Graduate School of Medicine Kobe Japan
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12
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Jiang C, Li HT, Zhou YM, Wang X, Wang L, Liu ZQ. Cardiac optogenetics: a novel approach to cardiovascular disease therapy. Europace 2019; 20:1741-1749. [PMID: 29253159 DOI: 10.1093/europace/eux345] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 10/24/2017] [Indexed: 12/13/2022] Open
Abstract
Optogenetics is a cell-type specific and high spatial-temporal resolution method that combines genetic encoding of light-sensitive proteins and optical manipulation techniques. Optogenetics technology provides a novel approach for research on cardiac arrhythmia treatment, including pacing, recovering the conduction system, and achieving cardiac resynchronization with precise and low-energy optical control. Photosensitive proteins, which usually act as ion channels, pumps, or receptors, are delivered to target cells, where they respond to light pulses of specific wavelengths, evoke transient flows of transmembrane ion currents, and induce signal transmission. With the development of gene technology, the in vivo efficiency of optogenetics in cardiology has been trialed, and in vitro experiments have been performed to test its potential in cardiac electrophysiology. Challenges for applying optogenetics in large animals and humans include the effectiveness, safety, and long-term expression of photosensitive proteins, unscattered and unattenuated exogenous light stimulation, and the need for implantable miniature light stimulators. Photosensitive proteins, genetic engineering technology, and light equipment are essential for experiments in cardiac optogenetics. Optogenetics may provide an alternative method for evaluating the mechanism of cardiac arrhythmias, testing hypotheses, and treating cardiovascular diseases.
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Affiliation(s)
- Chan Jiang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China.,Cardiovascular Research Institute, Wuhan University, Wuhan, PR China.,Hubei Key Laboratory of Cardiology, Wuhan, PR China
| | - Hai Tao Li
- Department of Cardiology, Hainan General Hospital, Haikou, PR China
| | - Yong Ming Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China.,Cardiovascular Research Institute, Wuhan University, Wuhan, PR China.,Hubei Key Laboratory of Cardiology, Wuhan, PR China
| | - Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China.,Cardiovascular Research Institute, Wuhan University, Wuhan, PR China.,Hubei Key Laboratory of Cardiology, Wuhan, PR China
| | - Long Wang
- Cardiovascular Research Institute, Wuhan University, Wuhan, PR China.,Hubei Key Laboratory of Cardiology, Wuhan, PR China.,Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Zi Qiang Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China.,Cardiovascular Research Institute, Wuhan University, Wuhan, PR China.,Hubei Key Laboratory of Cardiology, Wuhan, PR China
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13
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Mederos S, Hernández-Vivanco A, Ramírez-Franco J, Martín-Fernández M, Navarrete M, Yang A, Boyden ES, Perea G. Melanopsin for precise optogenetic activation of astrocyte-neuron networks. Glia 2019; 67:915-934. [PMID: 30632636 DOI: 10.1002/glia.23580] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/28/2018] [Accepted: 11/30/2018] [Indexed: 12/11/2022]
Abstract
Optogenetics has been widely expanded to enhance or suppress neuronal activity and it has been recently applied to glial cells. Here, we have used a new approach based on selective expression of melanopsin, a G-protein-coupled photopigment, in astrocytes to trigger Ca2+ signaling. Using the genetically encoded Ca2+ indicator GCaMP6f and two-photon imaging, we show that melanopsin is both competent to stimulate robust IP3-dependent Ca2+ signals in astrocyte fine processes, and to evoke an ATP/Adenosine-dependent transient boost of hippocampal excitatory synaptic transmission. Additionally, under low-frequency light stimulation conditions, melanopsin-transfected astrocytes can trigger long-term synaptic changes. In vivo, melanopsin-astrocyte activation enhances episodic-like memory, suggesting melanopsin as an optical tool that could recapitulate the wide range of regulatory actions of astrocytes on neuronal networks in behaving animals. These results describe a novel approach using melanopsin as a precise trigger for astrocytes that mimics their endogenous G-protein signaling pathways, and present melanopsin as a valuable optical tool for neuron-glia studies.
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Affiliation(s)
- Sara Mederos
- Department of Functional and Systems Neurobiology, Instituto Cajal, CSIC, Madrid, Spain
| | | | - Jorge Ramírez-Franco
- Department of Functional and Systems Neurobiology, Instituto Cajal, CSIC, Madrid, Spain
| | | | - Marta Navarrete
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Aimei Yang
- Media Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Edward S Boyden
- Media Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts.,McGovern Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Gertrudis Perea
- Department of Functional and Systems Neurobiology, Instituto Cajal, CSIC, Madrid, Spain
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14
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Mc Mahon B, Nørgaard M, Svarer C, Andersen SB, Madsen MK, Baaré WFC, Madsen J, Frokjaer VG, Knudsen GM. Seasonality-resilient individuals downregulate their cerebral 5-HT transporter binding in winter - A longitudinal combined 11C-DASB and 11C-SB207145 PET study. Eur Neuropsychopharmacol 2018; 28:1151-1160. [PMID: 30077433 DOI: 10.1016/j.euroneuro.2018.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 05/17/2018] [Accepted: 06/25/2018] [Indexed: 12/18/2022]
Abstract
We have recently shown that the emergence and severity of seasonal affective disorder (SAD) symptoms in the winter is associated with an increase in cerebral serotonin (5-HT) transporter (SERT) binding. Intriguingly, we also found that individuals resilient to SAD downregulate their cerebral SERT binding in the winter. In the present paper, we provide an analysis of the SERT- and 5-HT dynamics as indexed by 5-HT4 receptor (5-HT4R) binding related to successful stress coping. We included 46 11C-DASB positron emission tomography (PET) scans (N = 23, 13 women, age: 26 ± 6 years) and 14 11C-SB207145 PET scans (7 participants, 3 women, age: 25 ± 3 years) from 23 SAD-resilient Danes. Data was collected longitudinally in summer and winter. We found that compared to the summer, raphe nuclei and global brain SERT binding decreased significantly in the winter (praphe = 0.003 and pglobal = 0.003) and the two measures were positively correlated across seasons (summer: R2 = 0.33, p = .004, winter: R2 = 0.24, p = .018). A voxel-based analysis revealed prominent changes in SERT in clusters covering both angular gyri (0.0005 < pcorrected < 0.0016), prefrontal cortices (0.00087 < pcorrected < 0.0039) and the posterior temporal and adjacent occipital cortices (0.0001 < pcorrected < 0.0066). We did not observe changes in 5-HT4R binding, suggesting that 5-HT levels remained stable across seasons. We conclude that resilience to SAD is associated with a global downregulation of SERT levels in winter which serves to keep 5-HT levels across seasons.
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Affiliation(s)
- Brenda Mc Mahon
- Neurobiology Research Unit, Rigshospitalet and Center for Integrated Molecular Brain Imaging, Section 6931, Blegdamsvej 9, 2100 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
| | - Martin Nørgaard
- Neurobiology Research Unit, Rigshospitalet and Center for Integrated Molecular Brain Imaging, Section 6931, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Claus Svarer
- Neurobiology Research Unit, Rigshospitalet and Center for Integrated Molecular Brain Imaging, Section 6931, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Sofie B Andersen
- Neurobiology Research Unit, Rigshospitalet and Center for Integrated Molecular Brain Imaging, Section 6931, Blegdamsvej 9, 2100 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Martin K Madsen
- Neurobiology Research Unit, Rigshospitalet and Center for Integrated Molecular Brain Imaging, Section 6931, Blegdamsvej 9, 2100 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - William F C Baaré
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Kettegårds Allé 30, 2650 Hvidovre, Denmark
| | - Jacob Madsen
- PET and Cyclotron Unit, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Vibe G Frokjaer
- Neurobiology Research Unit, Rigshospitalet and Center for Integrated Molecular Brain Imaging, Section 6931, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Rigshospitalet and Center for Integrated Molecular Brain Imaging, Section 6931, Blegdamsvej 9, 2100 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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15
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Zeitzer JM. When is a proxy not a proxy? The foibles of studying non-image forming light. J Physiol 2018; 596:2029-2030. [PMID: 29717490 DOI: 10.1113/jp276076] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Jamie M Zeitzer
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, 94305, USA.,Stanford Center for Sleep Sciences and Medicine, Stanford University, Stanford, CA, 94305, USA.,Mental Illness Research, Education, and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA
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16
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Abstract
Photobiomodulation (PBM) also known as low-level level laser therapy is the use of red and near-infrared light to stimulate healing, relieve pain, and reduce inflammation. The primary chromophores have been identified as cytochrome c oxidase in mitochondria, and calcium ion channels (possibly mediated by light absorption by opsins). Secondary effects of photon absorption include increases in ATP, a brief burst of reactive oxygen species, an increase in nitric oxide, and modulation of calcium levels. Tertiary effects include activation of a wide range of transcription factors leading to improved cell survival, increased proliferation and migration, and new protein synthesis. There is a pronounced biphasic dose response whereby low levels of light have stimulating effects, while high levels of light have inhibitory effects. It has been found that PBM can produce ROS in normal cells, but when used in oxidatively stressed cells or in animal models of disease, ROS levels are lowered. PBM is able to up-regulate anti-oxidant defenses and reduce oxidative stress. It was shown that PBM can activate NF-kB in normal quiescent cells, however in activated inflammatory cells, inflammatory markers were decreased. One of the most reproducible effects of PBM is an overall reduction in inflammation, which is particularly important for disorders of the joints, traumatic injuries, lung disorders, and in the brain. PBM has been shown to reduce markers of M1 phenotype in activated macrophages. Many reports have shown reductions in reactive nitrogen species and prostaglandins in various animal models. PBM can reduce inflammation in the brain, abdominal fat, wounds, lungs, spinal cord.
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Affiliation(s)
- Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, BAR414, 40 Blossom Street, Boston, MA 02114, USA
- Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
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17
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Allen AE, Storchi R, Martial FP, Bedford RA, Lucas RJ. Melanopsin Contributions to the Representation of Images in the Early Visual System. Curr Biol 2017; 27:1623-1632.e4. [PMID: 28528909 PMCID: PMC5462620 DOI: 10.1016/j.cub.2017.04.046] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/18/2017] [Accepted: 04/21/2017] [Indexed: 11/19/2022]
Abstract
Melanopsin photoreception enhances retinal responses to variations in ambient light (irradiance) and drives non-image-forming visual reflexes such as circadian entrainment [1, 2, 3, 4, 5, 6]. Melanopsin signals also reach brain regions responsible for form vision [7, 8, 9], but melanopsin’s contribution, if any, to encoding visual images remains unclear. We addressed this deficit using principles of receptor silent substitution to present images in which visibility for melanopsin versus rods+cones was independently modulated, and we recorded evoked responses in the mouse dorsal lateral geniculate nucleus (dLGN; thalamic relay for cortical vision). Approximately 20% of dLGN units responded to patterns visible only to melanopsin, revealing that melanopsin signals alone can convey spatial information. Spatial receptive fields (RFs) mapped using melanopsin-isolating stimuli had ON centers with diameters ∼13°. Melanopsin and rod+cone responses differed in the temporal domain, and responses to slow changes in radiance (<0.9 Hz) and stationary images were deficient when stimuli were rendered invisible for melanopsin. We employed these data to devise and test a mathematical model of melanopsin’s involvement in form vision and applied it, along with further experimental recordings, to explore melanopsin signals under simulated active view of natural scenes. Our findings reveal that melanopsin enhances the thalamic representation of scenes containing local correlations in radiance, compensating for the high temporal frequency bias of cone vision and the negative correlation between magnitude and frequency for changes in direction of view. Together, these data reveal a distinct melanopsin contribution to encoding visual images, predicting that, under natural view, melanopsin augments the early visual system’s ability to encode patterns over moderate spatial scales. A five-primary display is used to define melanopsin’s contribution to form vision Melanopsin extends the spatiotemporal range of the mouse early visual system The representation of spatial patterns is deficient when melanopsin is not engaged A linear model predicting melanopsin’s contribution to pattern vision is defined
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Affiliation(s)
- Annette E Allen
- Division of Neuroscience and Experimental Psychology, School of Biology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK.
| | - Riccardo Storchi
- Division of Neuroscience and Experimental Psychology, School of Biology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Franck P Martial
- Division of Neuroscience and Experimental Psychology, School of Biology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Robert A Bedford
- Division of Neuroscience and Experimental Psychology, School of Biology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Robert J Lucas
- Division of Neuroscience and Experimental Psychology, School of Biology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK.
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18
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Michael AK, Fribourgh JL, Van Gelder RN, Partch CL. Animal Cryptochromes: Divergent Roles in Light Perception, Circadian Timekeeping and Beyond. Photochem Photobiol 2017; 93:128-140. [PMID: 27891621 DOI: 10.1111/php.12677] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 10/09/2016] [Indexed: 12/15/2022]
Abstract
Cryptochromes are evolutionarily related to the light-dependent DNA repair enzyme photolyase, serving as major regulators of circadian rhythms in insects and vertebrate animals. There are two types of cryptochromes in the animal kingdom: Drosophila-like CRYs that act as nonvisual photopigments linking circadian rhythms to the environmental light/dark cycle, and vertebrate-like CRYs that do not appear to sense light directly, but control the generation of circadian rhythms by acting as transcriptional repressors. Some animals have both types of CRYs, while others possess only one. Cryptochromes have two domains, the photolyase homology region (PHR) and an extended, intrinsically disordered C-terminus. While all animal CRYs share a high degree of sequence and structural homology in their PHR domains, the C-termini are divergent in both length and sequence identity. Recently, cryptochrome function has been shown to extend beyond its pivotal role in circadian clocks, participating in regulation of the DNA damage response, cancer progression and glucocorticoid signaling, as well as being implicated as possible magnetoreceptors. In this review, we provide a historical perspective on the discovery of animal cryptochromes, examine similarities and differences of the two types of animal cryptochromes and explore some of the divergent roles for this class of proteins.
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Affiliation(s)
- Alicia K Michael
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA
| | - Jennifer L Fribourgh
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA
| | | | - Carrie L Partch
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA.,Center for Circadian Biology, University of California San Diego, San Diego, CA
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19
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Nissilä JS, Mänttäri SK, Särkioja TT, Tuominen HJ, Takala TE, Kiviniemi VJ, Sormunen RT, Saarela SYO, Timonen MJ. The distribution of melanopsin (OPN4) protein in the human brain. Chronobiol Int 2016; 34:37-44. [PMID: 27690288 DOI: 10.1080/07420528.2016.1232269] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Until now, melanopsin (OPN4) - a specialized photopigment being responsive especially to blue light wavelengths - has not been found in the human brain at protein level outside the retina. More specifically, OPN4 has only been found in about 2% of retinal ganglion cells (i.e. in intrinsically photosensitive retinal ganglion cells), and in a subtype of retinal cone-cells. Given that Allen Institute for Brain Science has described a wide distribution of OPN4 mRNA in two human brains, we aimed to investigate whether OPN4 is present in the human brain also at protein level. Western blotting and immunohistochemistry, as well as immunoelectron microscopy, were used to analyse the existence and distribution of OPN4 protein in 18 investigated areas of the human brain in samples obtained in forensic autopsies from 10 male subjects (54 ± 3.5 years). OPN4 protein expression was found in all subjects, and, furthermore, in 5 out of 10 subjects in all investigated brain areas localized in membranous compartments and cytoplasmic vesicles of neurons. To our opinion, the wide distribution of OPN4 in central areas of the human brain evokes a question whether ambient light has important straight targets in the human brain outside the retinohypothalamic tract (RHT). Further studies are, however, needed to investigate the putative physiological phototransductive actions of inborn OPN4 protein outside the RHT in the human brain.
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Affiliation(s)
- Juuso S Nissilä
- a University of Oulu, Center for Life Course Health Research , Oulu , Finland.,b Department of Biology, University of Oulu , Oulu , Finland
| | - Satu K Mänttäri
- b Department of Biology, University of Oulu , Oulu , Finland
| | - Terttu T Särkioja
- c University of Oulu , Institute of Diagnostics, Forensic Medicine , Oulu , Finland
| | - Hannu J Tuominen
- d University of Oulu , Institute of Diagnostics, Pathology , Oulu , Finland.,e Department of Pathology , Oulu University Hospital , Oulu , Finland
| | | | - Vesa J Kiviniemi
- g Department of Diagnostic Radiology , Oulu University Hospital , Oulu , Finland
| | - Raija T Sormunen
- d University of Oulu , Institute of Diagnostics, Pathology , Oulu , Finland.,e Department of Pathology , Oulu University Hospital , Oulu , Finland.,h Biocenter Oulu , University of Oulu , Oulu , Finland
| | | | - Markku J Timonen
- a University of Oulu, Center for Life Course Health Research , Oulu , Finland
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20
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Prolonged Inner Retinal Photoreception Depends on the Visual Retinoid Cycle. J Neurosci 2016; 36:4209-17. [PMID: 27076420 DOI: 10.1523/jneurosci.2629-14.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 03/08/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED In addition to rods and cones, mammals have inner retinal photoreceptors called intrinsically photosensitive retinal ganglion cells (ipRGCs), which use the photopigment melanopsin and mediate nonimage-forming visual responses, such as pupil reflexes and circadian entrainment. After photic activation, photopigments must be reverted to their dark state to be light-sensitive again. For rods and to some extent cones, photopigment regeneration depends on the retinoid cycle in the adjacent retinal pigment epithelium (RPE). By contrast, ipRGCs are far from the RPE, and previous work suggests that melanopsin is capable of light-dependent self-regeneration. Here, we used in vitro ipRGC recording and in vivo pupillometry to show that the RPE is required for normal melanopsin-based responses to prolonged light, especially at high stimulus intensities. Melanopsin-based photoresponses of rat ipRGCs were remarkably sustained when a functional RPE was attached to the retina, but became far more transient if the RPE was removed, or if the retinoid cycle was inhibited, or when Müller glia were poisoned. Similarly, retinoid cycle inhibition markedly reduced the steady-state amplitude of melanopsin-driven pupil reflexes in both mice and rats. However, melanopsin photoresponses in RPE-separated rat retinas became more sustained in the presence of an 11-cis-retinal analog. In conclusion, during prolonged illumination, melanopsin regeneration depends partly on 11-cis-retinal from the RPE, possibly imported via Müller cells. Implications for RPE-related eye diseases and the acne drug isotretinoin (a retinoid cycle inhibitor) are discussed. SIGNIFICANCE STATEMENT Intrinsically photosensitive retinal ganglion cells (ipRGCs) contain the photopigment melanopsin and drive subconscious physiological responses to light, e.g., pupillary constriction and neuroendocrine regulation. In darkness, each photopigment molecule in ipRGCs, as well as rod/cone photoreceptors, contains 11-cis-retinal (a vitamin A derivative) and light isomerizes it to all-trans-retinal, which activates the photopigment. To make this photopigment excitable again,all-trans-retinal must be reisomerized to 11-cis-retinal. For rods and to some extent cones, this reisomerization occurs in the adjacent retinal pigment epithelium (RPE), but because ipRGCs are far from the RPE, they are thought to regenerate excitable melanopsin exclusively through RPE-independent means. Here, we present electrophysiological and behavioral evidence that ipRGCs depend on the RPE to continuously regenerate melanopsin during intense prolonged photostimulation.
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21
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Abstract
Circadian rhythms are self-sustained, approximately 24-h rhythms of physiology and behavior. These rhythms are entrained to an exactly 24-h period by the daily light-dark cycle. Remarkably, mice lacking all rod and cone photoreceptors still demonstrate photic entrainment, an effect mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells utilize melanopsin (OPN4) as their photopigment. Distinct from the ciliary rod and cone opsins, melanopsin appears to function as a stable photopigment utilizing sequential photon absorption for its photocycle; this photocycle, in turn, confers properties on ipRGCs such as sustained signaling and resistance from photic bleaching critical for an irradiance detection system. The retina itself also functions as a circadian pacemaker that can be autonomously entrained to light-dark cycles. Recent experiments have demonstrated that another novel opsin, neuropsin (OPN5), is required for this entrainment, which appears to be mediated by a separate population of ipRGCs. Surprisingly, the circadian clock of the mammalian cornea is also light entrainable and is also neuropsin-dependent for this effect. The retina thus utilizes a surprisingly broad array of opsins for mediation of different light-detection tasks.
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Affiliation(s)
- Russell N Van Gelder
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, Washington 98109.,Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98195.,Department of Biological Structure, University of Washington School of Medicine, Seattle, Washington 98195;
| | - Ethan D Buhr
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, Washington 98109
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22
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Fasick JI, Robinson PR. Adaptations of Cetacean Retinal Pigments to Aquatic Environments. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00070] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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23
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Liu MM, Dai JM, Liu WY, Zhao CJ, Lin B, Yin ZQ. Human melanopsin-AAV2/8 transfection to retina transiently restores visual function in rd1 mice. Int J Ophthalmol 2016; 9:655-61. [PMID: 27275417 DOI: 10.18240/ijo.2016.05.03] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 02/05/2016] [Indexed: 11/23/2022] Open
Abstract
AIM To explore whether ectopic expression of human melanopsin can effectively and safely restore visual function in rd1 mice. METHODS Hematoxylin-eosin staining of retinal sections from rd1 mice was used to detect the thickness of the outer nuclear layer to determine the timing of surgery. We constructed a human melanopsin-AAV2/8 viral vector and injected it into the subretinal space of rd1 mice. The Phoenix Micron IV system was used to exclude the aborted injections, and immunohistochemistry was used to validate the ectopic expression of human melanopsin. Furthermore, visual electrophysiology and behavioral tests were used to detect visual function 30 and 45d after the injection. The structure of the retina was compared between the human melanopsin-injected group and phosphate buffer saline (PBS)-injected group. RESULTS Retinas of rd1 mice lost almost all of their photoreceptors on postnatal day 28 (P28). We therefore injected the human melanopsin-adeno-associated virus (AAV) 2/8 viral vector into P30 rd1 mice. After excluding aborted injections, we used immunohistochemistry of the whole mount retina to confirm the ectopic expression of human melanopsin by co-expression of human melanopsin and YFP that was carried by a viral vector. At 30d post-injection, visual electrophysiology and the behavioral test significantly improved. However, restoration of vision disappeared 45d after human melanopsin injection. Notably, human melanopsin-injected mice did not show any structural differences in their retinas compared with PBS-injected mice. CONCLUSION Ectopic expression of human melanopsin effectively and safely restores visual function in rd1 mice.
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Affiliation(s)
- Ming-Ming Liu
- Southwest Hospital, Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing 400038, China
| | - Jia-Man Dai
- Southwest Hospital, Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing 400038, China
| | - Wen-Yi Liu
- Southwest Hospital, Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing 400038, China
| | - Cong-Jian Zhao
- Southwest Hospital, Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing 400038, China
| | - Bin Lin
- Departments of Anatomy and Ophthalmology, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong 200131, China
| | - Zheng-Qin Yin
- Southwest Hospital, Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China; Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing 400038, China
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24
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Daneault V, Dumont M, Massé É, Vandewalle G, Carrier J. Light-sensitive brain pathways and aging. J Physiol Anthropol 2016; 35:9. [PMID: 26980095 PMCID: PMC4791759 DOI: 10.1186/s40101-016-0091-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/01/2016] [Indexed: 01/08/2023] Open
Abstract
Notwithstanding its effects on the classical visual system allowing image formation, light acts upon several non-image-forming (NIF) functions including body temperature, hormonal secretions, sleep-wake cycle, alertness, and cognitive performance. Studies have shown that NIF functions are maximally sensitive to blue wavelengths (460–480 nm), in comparison to longer light wavelengths. Higher blue light sensitivity has been reported for melatonin suppression, pupillary constriction, vigilance, and performance improvement but also for modulation of cognitive brain functions. Studies investigating acute stimulating effects of light on brain activity during the execution of cognitive tasks have suggested that brain activations progress from subcortical regions involved in alertness, such as the thalamus, the hypothalamus, and the brainstem, before reaching cortical regions associated with the ongoing task. In the course of aging, lower blue light sensitivity of some NIF functions has been reported. Here, we first describe neural pathways underlying effects of light on NIF functions and we discuss eye and cerebral mechanisms associated with aging which may affect NIF light sensitivity. Thereafter, we report results of investigations on pupillary constriction and cognitive brain sensitivity to light in the course of aging. Whereas the impact of light on cognitive brain responses appears to decrease substantially, pupillary constriction seems to remain more intact over the lifespan. Altogether, these results demonstrate that aging research should take into account the diversity of the pathways underlying the effects of light on specific NIF functions which may explain their differences in light sensitivity.
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Affiliation(s)
- V Daneault
- Functional Neuroimaging Unit, University of Montreal Geriatric Institute, Montreal, QC, Canada. .,Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada. .,Department of Psychology, University of Montreal, Montreal, QC, Canada.
| | - M Dumont
- Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada
| | - É Massé
- Functional Neuroimaging Unit, University of Montreal Geriatric Institute, Montreal, QC, Canada.,Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada
| | - G Vandewalle
- Department of Psychology, University of Montreal, Montreal, QC, Canada.,Cyclotron Research Centre, University of Liège, Liège, Belgium
| | - J Carrier
- Functional Neuroimaging Unit, University of Montreal Geriatric Institute, Montreal, QC, Canada.,Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada.,Department of Psychology, University of Montreal, Montreal, QC, Canada
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25
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Light and the evolution of vision. Eye (Lond) 2015; 30:173-8. [PMID: 26541087 DOI: 10.1038/eye.2015.220] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 09/22/2015] [Indexed: 01/09/2023] Open
Abstract
It might seem a little ridiculous to cover the period over which vision evolved, perhaps 1.5 billion years, in only 3000 words. Yet, if we examine the photoreceptor molecules of the most basic eukaryote protists and even before that, in those of prokaryote bacteria and cyanobacteria, we see how similar they are to those of mammalian rod and cone photoreceptor opsins and the photoreceptive molecules of light sensitive ganglion cells. This shows us much with regard the development of vision once these proteins existed, but there is much more to discover about the evolution of even more primitive vision systems.
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26
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Sexton TJ, Bleckert A, Turner MH, Van Gelder RN. Type I intrinsically photosensitive retinal ganglion cells of early post-natal development correspond to the M4 subtype. Neural Dev 2015; 10:17. [PMID: 26091805 PMCID: PMC4480886 DOI: 10.1186/s13064-015-0042-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 06/03/2015] [Indexed: 12/16/2022] Open
Abstract
Background Intrinsically photosensitive retinal ganglion cells (ipRGCs) mediate circadian light entrainment and the pupillary light response in adult mice. In early development these cells mediate different processes, including negative phototaxis and the timing of retinal vascular development. To determine if ipRGC physiologic properties also change with development, we measured ipRGC cell density and light responses in wild-type mouse retinas at post-natal days 8, 15 and 30. Results Melanopsin-positive cell density decreases by 17 % between post-natal days 8 and 15 and by 25 % between days 8 and 30. This decrease is due specifically to a decrease in cells co-labeled with a SMI-32, a marker for alpha-on ganglion cells (corresponding to adult morphologic type M4 ipRGCs). On multi-electrode array recordings, post-natal day 8 (P8) ipRGC light responses show more robust firing, reduced adaptation and more rapid recovery from short and extended light pulses than do the light responses of P15 and P30 ipRGCs. Three ipRGC subtypes – Types I-III – have been defined in early development based on sensitivity and latency on multielectrode array recordings. We find that Type I cells largely account for the unique physiologic properties of P8 ipRGCs. Type I cells have previously been shown to have relatively short latencies and high sensitivity. We now show that Type I cells show have rapid and robust recovery from long and short bright light exposures compared with Type II and III cells, suggesting differential light adaptation mechanisms between cell types. By P15, Type I ipRGCs are no longer detectable. Loose patch recordings of P8 M4 ipRGCs demonstrate Type I physiology. Conclusions Type I ipRGCs are found only in early development. In addition to their previously described high sensitivity and rapid kinetics, these cells are uniquely resistant to adaptation and recover quickly and fully to short and prolonged light exposure. Type I ipRGCs correspond to the SMI-32 positive, M4 subtype and largely lose melanopsin expression in development. These cells constitute a unique morphologic and physiologic class of ipRGCs functioning early in postnatal development. Electronic supplementary material The online version of this article (doi:10.1186/s13064-015-0042-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Timothy J Sexton
- Department of Ophthalmology, University of Washington, 325 9th Avenue, Seattle, WA, 98104, USA. .,Program in Neurobiology and Behavior, University of Washington, Health Sciences Center, Seattle, WA, 98195, USA.
| | - Adam Bleckert
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA. .,Program in Neurobiology and Behavior, University of Washington, Health Sciences Center, Seattle, WA, 98195, USA.
| | - Maxwell H Turner
- Department of Physiology & Biophysics, University of Washington, 1705 NE Pacific St., Seattle, WA, 98195, USA. .,Program in Neurobiology and Behavior, University of Washington, Health Sciences Center, Seattle, WA, 98195, USA.
| | - Russell N Van Gelder
- Department of Ophthalmology, University of Washington, 325 9th Avenue, Seattle, WA, 98104, USA. .,Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA. .,Department of Pathology, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA. .,Program in Neurobiology and Behavior, University of Washington, Health Sciences Center, Seattle, WA, 98195, USA.
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G-Protein Coupled Receptor Kinase 2 Minimally Regulates Melanopsin Activity in Intrinsically Photosensitive Retinal Ganglion Cells. PLoS One 2015; 10:e0128690. [PMID: 26069965 PMCID: PMC4467020 DOI: 10.1371/journal.pone.0128690] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 04/29/2015] [Indexed: 12/20/2022] Open
Abstract
Phosphorylation is a primary modulator of mammalian G-protein coupled receptor (GPCR) activity. The GPCR melanopsin is the photopigment of intrinsically photosensitive retinal ganglion cells (ipRGCs) in the mammalian retina. Recent evidence from in vitro experiments suggests that the G-protein coupled receptor kinase 2 (GRK2) phosphorylates melanopsin and reduces its activity following light exposure. Using an ipRGC-specific GRK2 loss-of-function mouse, we show that GRK2 loss alters melanopsin response dynamics and termination time in postnatal day 8 (P8) ipRGCs but not in older animals. However, the alterations are small in comparison to the changes reported for other opsins with loss of their cognate GRK. These results suggest GRK2 contributes to melanopsin deactivation, but that other mechanisms account for most of modulation of melanopsin activity in ipRGCs.
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Xie AX, Petravicz J, McCarthy KD. Molecular approaches for manipulating astrocytic signaling in vivo. Front Cell Neurosci 2015; 9:144. [PMID: 25941472 PMCID: PMC4403552 DOI: 10.3389/fncel.2015.00144] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 03/27/2015] [Indexed: 12/26/2022] Open
Abstract
Astrocytes are the predominant glial type in the central nervous system and play important roles in assisting neuronal function and network activity. Astrocytes exhibit complex signaling systems that are essential for their normal function and the homeostasis of the neural network. Altered signaling in astrocytes is closely associated with neurological and psychiatric diseases, suggesting tremendous therapeutic potential of these cells. To further understand astrocyte function in health and disease, it is important to study astrocytic signaling in vivo. In this review, we discuss molecular tools that enable the selective manipulation of astrocytic signaling, including the tools to selectively activate and inactivate astrocyte signaling in vivo. Lastly, we highlight a few tools in development that present strong potential for advancing our understanding of the role of astrocytes in physiology, behavior, and pathology.
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Affiliation(s)
- Alison X Xie
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Jeremy Petravicz
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Ken D McCarthy
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill Chapel Hill, NC, USA
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29
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Crane BR, Young MW. Interactive features of proteins composing eukaryotic circadian clocks. Annu Rev Biochem 2015; 83:191-219. [PMID: 24905781 DOI: 10.1146/annurev-biochem-060713-035644] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Research into the molecular mechanisms of eukaryotic circadian clocks has proceeded at an electrifying pace. In this review, we discuss advances in our understanding of the structures of central molecular players in the timing oscillators of fungi, insects, and mammals. A series of clock protein structures demonstrate that the PAS (Per/Arnt/Sim) domain has been used with great variation to formulate the transcriptional activators and repressors of the clock. We discuss how posttranslational modifications and external cues, such as light, affect the conformation and function of core clock components. Recent breakthroughs have also revealed novel interactions among clock proteins and new partners that couple the clock to metabolic and developmental pathways. Overall, a picture of clock function has emerged wherein conserved motifs and structural platforms have been elaborated into a highly dynamic collection of interacting molecules that undergo orchestrated changes in chemical structure, conformational state, and partners.
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Affiliation(s)
- Brian R Crane
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853;
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30
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31
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Three-week bright-light intervention has dose-related effects on threat-related corticolimbic reactivity and functional coupling. Biol Psychiatry 2014; 76:332-9. [PMID: 24439303 DOI: 10.1016/j.biopsych.2013.11.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/22/2013] [Accepted: 11/30/2013] [Indexed: 12/11/2022]
Abstract
BACKGROUND Bright-light intervention is reported to successfully treat depression, in particular seasonal affective disorder, but the neural pathways and molecular mechanisms mediating its effects are unclear. An amygdala-prefrontal cortex corticolimbic circuit regulates responses to salient environmental stimuli (e.g., threat) and may underlie these effects. Serotonin signaling modulates this circuit and is implicated in the pathophysiology of seasonal and other affective disorders. METHODS We evaluated the effects of a bright-light intervention protocol on threat-related corticolimbic reactivity and functional coupling, assessed with an emotional faces functional magnetic resonance imaging paradigm at preintervention and postintervention. In a double-blind study conducted in the winter, 30 healthy male subjects received bright-light intervention (dose range between participants: .1-11.0 kilolux) for 30 minutes daily over a period of 3 weeks. Additionally, we considered serotonin transporter-linked polymorphic region (5-HTTLPR) genotype status as a model for differences in serotonin signaling and moderator of intervention effects. RESULTS Bright-light dose significantly negatively affected threat-related amygdala and prefrontal reactivity in a dose-dependent manner. Conversely, amygdala-prefrontal and intraprefrontal functional coupling increased significantly in a dose-dependent manner. Genotype status significantly moderated bright-light intervention effects on intraprefrontal functional coupling. CONCLUSIONS This is the first study to evaluate the effects of clinically relevant bright-light intervention on threat-related brain function. We show that amygdala-prefrontal reactivity and communication are significantly affected by bright-light intervention, an effect partly moderated by genotype. These novel findings support that this threat-related corticolimbic circuit is sensitive to light intervention and may mediate the therapeutic effects of bright-light intervention.
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32
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Teng J, Loukin S, Anishkin A, Kung C. The force-from-lipid (FFL) principle of mechanosensitivity, at large and in elements. Pflugers Arch 2014; 467:27-37. [PMID: 24888690 DOI: 10.1007/s00424-014-1530-2] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 04/29/2014] [Accepted: 05/05/2014] [Indexed: 12/27/2022]
Abstract
Focus on touch and hearing distracts attention from numerous subconscious force sensors, such as the vital control of blood pressure and systemic osmolarity, and sensors in nonanimals. Multifarious manifestations should not obscure invariant and fundamental physicochemical principles. We advocate that force from lipid (FFL) is one such principle. It is based on the fact that the self-assembled bilayer necessitates inherent forces that are large and anisotropic, even at life's origin. Functional response of membrane proteins is governed by bilayer force changes. Added stress can redirect these forces, leading to geometric changes of embedded proteins such as ion channels. The FFL principle was first demonstrated when purified bacterial mechanosensitive channel of large conductance (MscL) remained mechanosensitive (MS) after reconstituting into bilayers. This key experiment has recently been unequivocally replicated with two vertebrate MS K2p channels. Even the canonical Kv and the Drosophila canonical transient receptor potentials (TRPCs) have now been shown to be MS in biophysical and in physiological contexts, supporting the universality of the FFL paradigm. We also review the deterministic role of mechanical force during stem cell differentiation as well as the cell-cell and cell-matrix tethers that provide force communications. In both the ear hair cell and the worm's touch neuron, deleting the cadherin or microtubule tethers reduces but does not eliminate MS channel activities. We found no evidence to distinguish whether these tethers directly pull on the channel protein or a surrounding lipid platform. Regardless of the implementation, pulling tether tenses up the bilayer. Membrane tenting is directly visible at the apexes of the stereocilia.
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Affiliation(s)
- Jinfeng Teng
- Laboratory of Molecular Biology, University of Wisconsin, Madison, WI, 53706, USA
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33
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Feeling the hidden mechanical forces in lipid bilayer is an original sense. Proc Natl Acad Sci U S A 2014; 111:7898-905. [PMID: 24850861 DOI: 10.1073/pnas.1313364111] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Life's origin entails enclosing a compartment to hoard material, energy, and information. The envelope necessarily comprises amphipaths, such as prebiotic fatty acids, to partition the two aqueous domains. The self-assembled lipid bilayer comes with a set of properties including its strong anisotropic internal forces that are chemically or physically malleable. Added bilayer stretch can alter force vectors on embedded proteins to effect conformational change. The force-from-lipid principle was demonstrated 25 y ago when stretches opened purified Escherichia coli MscL channels reconstituted into artificial bilayers. This reductionistic exercise has rigorously been recapitulated recently with two vertebrate mechanosensitive K(+) channels (TREK1 and TRAAK). Membrane stretches have also been known to activate various voltage-, ligand-, or Ca(2+)-gated channels. Careful analyses showed that Kv, the canonical voltage-gated channel, is in fact exquisitely sensitive even to very small tension. In an unexpected context, the canonical transient-receptor-potential channels in the Drosophila eye, long presumed to open by ligand binding, is apparently opened by membrane force due to PIP2 hydrolysis-induced changes in bilayer strain. Being the intimate medium, lipids govern membrane proteins by physics as well as chemistry. This principle should not be a surprise because it parallels water's paramount role in the structure and function of soluble proteins. Today, overt or covert mechanical forces govern cell biological processes and produce sensations. At the genesis, a bilayer's response to osmotic force is likely among the first senses to deal with the capricious primordial sea.
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34
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Colors cast long shadows on brain activity. Proc Natl Acad Sci U S A 2014; 111:5769-70. [DOI: 10.1073/pnas.1403596111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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35
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Blasic JR, Matos-Cruz V, Ujla D, Cameron EG, Hattar S, Halpern ME, Robinson PR. Identification of critical phosphorylation sites on the carboxy tail of melanopsin. Biochemistry 2014; 53:2644-9. [PMID: 24678795 PMCID: PMC4010260 DOI: 10.1021/bi401724r] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
![]()
Light-activated
opsins undergo carboxy-terminal phosphorylation,
which contributes to the deactivation of their photoresponse. The
photopigment melanopsin possesses an unusually long carboxy tail containing
37 serine and threonine sites that are potential sites for phosphorylation
by a G-protein dependent kinase (GRK). Here, we show that a small
cluster of six to seven sites is sufficient for deactivation of light-activated
mouse melanopsin. Surprisingly, these sites are distinct from those
that regulate deactivation of rhodopsin. In zebrafish, there are five
different melanopsin genes that encode proteins with distinct carboxy-terminal
domains. Naturally occurring changes in the same cluster of phosphorylatable
amino acids provides diversity in the deactivation kinetics of the
zebrafish proteins. These results suggest that variation in phosphorylation
sites provides flexibility in the duration and kinetics of melanopsin-mediated
light responses.
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Affiliation(s)
- Joseph R Blasic
- Department of Biological Sciences, University of Maryland, Baltimore County , Baltimore, Maryland 21250, United States
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36
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Beiert T, Bruegmann T, Sasse P. Optogenetic activation of Gq signalling modulates pacemaker activity of cardiomyocytes. Cardiovasc Res 2014; 102:507-16. [PMID: 24576953 DOI: 10.1093/cvr/cvu046] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Investigation of Gq signalling with pharmacological agonists of Gq-coupled receptors lacks spatio-temporal precision. The aim of this study was to establish melanopsin, a light-sensitive Gq-coupled receptor, as a new tool for the investigation of spatial and temporal effects of Gq stimulation on pacemaking in cardiomyocytes at an early developmental stage. METHODS AND RESULTS A vector for ubiquitous expression of melanopsin was tested in HEK293FT cells, which showed light-induced production of inositol-1,4,5-trisphosphate and elevation of intracellular Ca(2+) concentration. Mouse embryonic stem cells were stably transfected with this plasmid and differentiated into spontaneously beating embryoid bodies (EBs). Cardiomyocytes within EBs showed melanopsin expression and illumination (60 s, 308.5 nW/mm(2), 470 nm) of EBs increased beating rate within 10.2 ± 1.7 s to 317.1 ± 16.3% of baseline frequency. Illumination as short as 5 s was sufficient for generating the maximal frequency response. After termination of illumination, baseline frequency was reached with a decay constant of 27.1 ± 2.5 s. The light-induced acceleration of beating frequency showed a sigmoid dependence on light intensity with a half maximal effective light intensity of 41.7 nW/mm(2). Interestingly, EBs showed a high rate of irregular contractions after termination of high-intensity illumination. Local Gq activation by illumination of a small region in a functional syncytium of cardiomyocytes led to pacemaker activity within the illuminated area. CONCLUSIONS Light-induced Gq activation in melanopsin-expressing cardiomyocytes increases beating rate and generates local pacemaker activity. We propose that melanopsin is a powerful optogenetic tool for the investigation of spatial and temporal aspects of Gq signalling in cardiovascular research.
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Affiliation(s)
- Thomas Beiert
- Institute of Physiology I, Life & Brain Center, University of Bonn, Sigmund-Freud-Strasse 25, Bonn 53105, Germany
| | - Tobias Bruegmann
- Institute of Physiology I, Life & Brain Center, University of Bonn, Sigmund-Freud-Strasse 25, Bonn 53105, Germany
| | - Philipp Sasse
- Institute of Physiology I, Life & Brain Center, University of Bonn, Sigmund-Freud-Strasse 25, Bonn 53105, Germany
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37
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Liu W, Tang FL, Erion J, Xiao H, Ye J, Xiong WC. Vps35 haploinsufficiency results in degenerative-like deficit in mouse retinal ganglion neurons and impairment of optic nerve injury-induced gliosis. Mol Brain 2014; 7:10. [PMID: 24512632 PMCID: PMC4016418 DOI: 10.1186/1756-6606-7-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 02/08/2014] [Indexed: 03/28/2023] Open
Abstract
VPS35 (vacuolar protein sorting 35) is a major component of retromer that selectively promotes endosome-to-Golgi retrieval of transmembrane proteins. Dysfunction of retromer is a risk factor for the pathogenesis of Parkinson’s disease (PD) and Alzheimer’s disease (AD), both neuro-degeneration disorders. However, VPS35/retromer’s function in retina or the contribution of Vps35-deficiency to retinal neuro-degenerative disorders has not been investigated. Here we provide evidence for a role of VPS35 in mouse retinal ganglion cell (RGC) survival and regeneration. VPS35 is selectively expressed in developing mouse RGCs. RGCs from young adult Vps35 heterozygotes (Vps35+/m) show degenerative-like features, such as dystrophic dendrites, reduced axon fibers, and increased TUNEL labeled RGCs. Additionally, gliosis in the optic nerve is transiently elevated in neonatal, but reduced in aged Vps35+/m mice. Optic nerve injury-induced gliosis is also attenuated in Vps35+/m mice. These results suggest that Vps35 is necessary for mouse RGC survival and regeneration, and Vps35-deficiency may contribute to the pathogenesis of retinal ganglion neuro-degeneration, a critical pathology leading to the blindness of many retinal degenerative disorders.
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Affiliation(s)
| | | | | | | | - Jian Ye
- Department of Ophthalmology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China.
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Najjar RP, Chiquet C, Teikari P, Cornut PL, Claustrat B, Denis P, Cooper HM, Gronfier C. Aging of non-visual spectral sensitivity to light in humans: compensatory mechanisms? PLoS One 2014; 9:e85837. [PMID: 24465738 PMCID: PMC3900444 DOI: 10.1371/journal.pone.0085837] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/02/2013] [Indexed: 11/30/2022] Open
Abstract
The deterioration of sleep in the older population is a prevalent feature that contributes to a decrease in quality of life. Inappropriate entrainment of the circadian clock by light is considered to contribute to the alteration of sleep structure and circadian rhythms in the elderly. The present study investigates the effects of aging on non-visual spectral sensitivity to light and tests the hypothesis that circadian disturbances are related to a decreased light transmittance. In a within-subject design, eight aged and five young subjects were exposed at night to 60 minute monochromatic light stimulations at 9 different wavelengths (420-620 nm). Individual sensitivity spectra were derived from measures of melatonin suppression. Lens density was assessed using a validated psychophysical technique. Although lens transmittance was decreased for short wavelength light in the older participants, melatonin suppression was not reduced. Peak of non-visual sensitivity was, however, shifted to longer wavelengths in the aged participants (494 nm) compared to young (484 nm). Our results indicate that increased lens filtering does not necessarily lead to a decreased non-visual sensitivity to light. The lack of age-related decrease in non-visual sensitivity to light may involve as yet undefined adaptive mechanisms.
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Affiliation(s)
- Raymond P. Najjar
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| | - Christophe Chiquet
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University Joseph Fourier Grenoble 1, Grenoble, France
- Department of Ophthalmology, CHU Grenoble, Grenoble, France
| | - Petteri Teikari
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| | - Pierre-Loïc Cornut
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- Department of Ophthalmology, CHU de Lyon Hôpital Edouard Herriot, Lyon, France
| | - Bruno Claustrat
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- Center of Biology, Hormone Laboratory, Bron, France
| | - Philippe Denis
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- Department of Ophtalmology, Hôpital de la Croix-Rousse, Lyon, France
| | - Howard M. Cooper
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| | - Claude Gronfier
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
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Bolze CS, Helbling RE, Owen RL, Pearson AR, Pompidor G, Dworkowski F, Fuchs MR, Furrer J, Golczak M, Palczewski K, Cascella M, Stocker A. Human cellular retinaldehyde-binding protein has secondary thermal 9-cis-retinal isomerase activity. J Am Chem Soc 2013; 136:137-46. [PMID: 24328211 DOI: 10.1021/ja411366w] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cellular retinaldehyde-binding protein (CRALBP) chaperones 11-cis-retinal to convert opsin receptor molecules into photosensitive retinoid pigments of the eye. We report a thermal secondary isomerase activity of CRALBP when bound to 9-cis-retinal. UV/vis and (1)H NMR spectroscopy were used to characterize the product as 9,13-dicis-retinal. The X-ray structure of the CRALBP mutant R234W:9-cis-retinal complex at 1.9 Å resolution revealed a niche in the binding pocket for 9-cis-aldehyde different from that reported for 11-cis-retinal. Combined computational, kinetic, and structural data lead us to propose an isomerization mechanism catalyzed by a network of buried waters. Our findings highlight a specific role of water molecules in both CRALBP-assisted specificity toward 9-cis-retinal and its thermal isomerase activity yielding 9,13-dicis-retinal. Kinetic data from two point mutants of CRALBP support an essential role of Glu202 as the initial proton donor in this isomerization reaction.
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Affiliation(s)
- Christin S Bolze
- Department of Chemistry and Biochemistry, and ‡Graduate School for Cellular and Biomedical Sciences, University of Bern , Freiestrasse 3, 3012 Bern, Switzerland
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Ramsey DJ, Ramsey KM, Vavvas DG. Genetic advances in ophthalmology: the role of melanopsin-expressing, intrinsically photosensitive retinal ganglion cells in the circadian organization of the visual system. Semin Ophthalmol 2013; 28:406-21. [PMID: 24010846 DOI: 10.3109/08820538.2013.825294] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Daily changes in the light-dark cycle are the principal environmental signal that enables organisms to synchronize their internal biology with the 24-hour day-night cycle. In humans, the visual system is integral to photoentrainment and is primarily driven by a specialized class of intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the photopigment melanopsin (OPN4) in the inner retina. These cells project through the retinohypothalamic tract (RHT) to the suprachiasmatic nuclei (SCN) of the hypothalamus, which serves as the body's master biological clock. At the same time, the retina itself possesses intrinsic circadian oscillations, exemplified by diurnal fluctuations in visual sensitivity, neurotransmitter levels, and outer segment turnover rates. Recently, it has been noted that both central and peripheral oscillators share a molecular clock consisting of an endogenous, circadian-driven, transcription-translation feedback loop that cycles with a periodicity of approximately 24 hours. This review will cover the role that melanopsin and ipRGCs play in the circadian organization of the visual system.
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Affiliation(s)
- David J Ramsey
- Retina Service, Harvard Medical School, Massachusetts Eye and Ear Infirmary and Mass General Hospital , Boston, Massachusetts , USA
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41
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Matynia A. Blurring the boundaries of vision: novel functions of intrinsically photosensitive retinal ganglion cells. J Exp Neurosci 2013; 7:43-50. [PMID: 25157207 PMCID: PMC4089729 DOI: 10.4137/jen.s11267] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mammalian vision consists of the classic image-forming pathway involving rod and cone photoreceptors interacting through a neural network within the retina before sending signals to the brain, and a non image-forming pathway that uses a photosensitive cell employing an alternative and evolutionary ancient phototransduction system and a direct connection to various centers in the brain. Intrinsically photosensitive retinal ganglion cells (ipRGCs) contain the photopigment melanopsin, which is independently capable of photon detection while also receiving synaptic input from rod and cone photoreceptors via bipolar cells. These cells are the retinal sentry for subconscious visual processing that controls circadian photoentrainment and the pupillary light reflex. Classified as irradiance detectors, recent investigations have led to expanding roles for this specific cell type and its own neural pathways, some of which are blurring the boundaries between image-forming and non image-forming visual processes.
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Affiliation(s)
- Anna Matynia
- Department of Ophthalmology, Jules Stein Eye Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA. ; Brain Research Institute, UCLA, Los Angeles, CA
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42
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Large scale expression and purification of mouse melanopsin-L in the baculovirus expression system. Protein Expr Purif 2013; 91:134-46. [PMID: 23921072 DOI: 10.1016/j.pep.2013.07.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 07/14/2013] [Accepted: 07/17/2013] [Indexed: 11/22/2022]
Abstract
Melanopsin is the mammalian photopigment that primarily mediates non-visual photoregulated physiology. So far, this photopigment is poorly characterized with respect to structure and function. Here, we report large-scale production and purification of the intact long isoform of mouse melanopsin (melanopsin-L) using the baculovirus/insect cell expression system. Exploiting the baculoviral GP67 signal peptide, we obtained expression levels that varied between 10-30pmol/10(6)cells, equivalent to 2-5mg/L. This could be further enhanced using DMSO as a chemical chaperone. LC-MS analysis confirmed that full-length melanopsin-L was expressed and demonstrated that the majority of the expressed protein was N-glycosylated at Asn(30) and Asn(34). Other posttranslational modifications were not yet detected. Purification was achieved exploiting a C-terminal deca-histag, realizing a purification factor of several hundred-fold. The final recovery of purified melanopsin-L averaged 2.5% of the starting material. This was mainly due to low extraction yields, probably since most of the protein was present as the apoprotein. The spectral data we obtained agree with an absorbance maximum in the 460-500nm wavelength region and a significant red-shift upon illumination. This is the first report on expression and purification of full length melanopsin-L at a scale that can easily be further amplified.
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Cascella M, Bärfuss S, Stocker A. Cis-retinoids and the chemistry of vision. Arch Biochem Biophys 2013; 539:187-95. [PMID: 23791723 DOI: 10.1016/j.abb.2013.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/04/2013] [Accepted: 06/10/2013] [Indexed: 11/17/2022]
Abstract
We discuss here principal biochemical transformations of retinoid molecules in the visual cycle. We focus our analysis on the accumulating evidence of alternate pathways and functional redundancies in the cycle. The efficiency of the visual cycle depends, on one hand, on fast regeneration of the photo-bleached chromophores. On the other hand, it is crucial that the cyclic process should be highly selective to avoid accumulation of byproducts. The state-of-the-art knowledge indicates that single enzymatically active components of the cycle are not strictly selective and may require chaperones to enhance their rates. It appears that protein-protein interactions significantly improve the biological stability of the visual cycle. In particular, synthesis of thermodynamically less stable 11-cis-retinoid conformers is favored by physical interactions of the isomerases present in the retina with cellular retinaldehyde binding protein.
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Affiliation(s)
- Michele Cascella
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
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Lemaire JJ, Nezzar H, Sakka L, Boirie Y, Fontaine D, Coste A, Coll G, Sontheimer A, Sarret C, Gabrillargues J, De Salles A. Maps of the adult human hypothalamus. Surg Neurol Int 2013; 4:S156-63. [PMID: 23682342 PMCID: PMC3654779 DOI: 10.4103/2152-7806.110667] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 02/01/2013] [Indexed: 01/14/2023] Open
Abstract
The human hypothalamus is a small deeply located region placed at the crossroad of neurovegetative, neuroendocrine, limbic, and optic systems. Although deep brain stimulation techniques have proven that it could be feasible to modulate these systems, targeting the hypothalamus and in particular specific nuclei and white bundles, is still challenging. Our goal was to make a synthesis of relevant topographical data of the human hypothalamus, under the form of magnetic resonance imaging maps useful for mastering its elaborated structure as well as its neighborhood. As from 1.5 Tesla, Inversion-Recovery sequence allows locating the hypothalamus and most of its components. Spotting hypothalamic compartments is possible according to specific landmarks: the anterior commissure, the mammillary bodies, the preoptic recess, the infundibular recess, the crest between the preoptic and the infundibular recesses, the optical tract, the fornix, and the mammillo-thalamic bundle. The identification of hypothalamus and most of its components could be useful to allow the quantification of local pathological processes and to target specific circuitry to alleviate severe symptoms, using physical or biological agents.
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Affiliation(s)
- Jean-Jacques Lemaire
- Univ Clermont 1, UFR Médecine, EA 7282, Image-Guided Clinical Neuroscience and Connectomics, Clermont-Ferrand, F-63001, France ; Service de Neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, F-63003, France
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Brown TM, Allen AE, al-Enezi J, Wynne J, Schlangen L, Hommes V, Lucas RJ. The melanopic sensitivity function accounts for melanopsin-driven responses in mice under diverse lighting conditions. PLoS One 2013; 8:e53583. [PMID: 23301090 PMCID: PMC3536742 DOI: 10.1371/journal.pone.0053583] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 12/03/2012] [Indexed: 12/19/2022] Open
Abstract
In addition to rods and cones, photoreception in mammals extends to a third retinal cell type expressing the photopigment melanopsin. The influences of this novel opsin are widespread, ranging from pupillary and circadian responses to brightness perception, yet established approaches to quantifying the biological effects of light do not adequately account for melanopsin sensitivity. We have recently proposed a novel metric, the melanopic sensitivity function (V(Z)λ), to address this deficiency. Here, we further validate this new measure with a variety of tests based on potential barriers to its applicability identified in the literature or relating to obvious practical benefits. Using electrophysiogical approaches and pupillometry, initially in rodless+coneless mice, our data demonstrate that under a very wide range of different conditions (including switching between stimuli with highly divergent spectral content) the V(Z)λ function provides an accurate prediction of the sensitivity of melanopsin-dependent responses. We further show that V(Z)λ provides the best available description of the spectral sensitivity of at least one aspect of the visual response in mice with functional rods and cones: tonic firing activity in the lateral geniculate nuclei. Together, these data establish V(Z)λ as an important new approach for light measurement with widespread practical utility.
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Affiliation(s)
- Timothy M. Brown
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Annette E. Allen
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Jazi al-Enezi
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Jonathan Wynne
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | | | - Vanja Hommes
- Philips Consumer Lifestyle, Drachten, The Netherlands
| | - Robert J. Lucas
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail:
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Ectopic expression of melanopsin in orexin/hypocretin neurons enables control of wakefulness of mice in vivo by blue light. Neurosci Res 2013; 75:23-8. [DOI: 10.1016/j.neures.2012.07.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/27/2012] [Indexed: 11/19/2022]
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Koizumi A, Tanaka KF, Yamanaka A. The manipulation of neural and cellular activities by ectopic expression of melanopsin. Neurosci Res 2013; 75:3-5. [DOI: 10.1016/j.neures.2012.07.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/26/2012] [Accepted: 06/27/2012] [Indexed: 12/01/2022]
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Hilton JD, Brady AK, Spaho SA, Vize PD. Photoreception and signal transduction in corals: proteomic and behavioral evidence for cytoplasmic calcium as a mediator of light responsivity. THE BIOLOGICAL BULLETIN 2012; 223:291-299. [PMID: 23264475 DOI: 10.1086/bblv223n3p291] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Little is known about how corals sense and respond to light. In this report the proteome of coral is explored using 2D protein electrophoresis in two species, Montastraea cavernosa and Acropora millepora. Multiple protein species have major shifts in abundance in both species when sampled in daylight compared to corals sampled late in the night. These changes were observed both in larvae lacking zooxanthellae and in adult tissue containing zooxanthellae, including both Pacific and Caribbean corals. When larvae kept in the dark were treated with either thapsigargin or ionomycin, compounds that raise the level of cytoplasmic calcium, the night pattern of proteins shifted to the day pattern. This implies that photoreceptors responding to light elevate calcium levels and that calcium acts as the second messenger relaying light responses in corals. Corals spawn at night, and spawning can be delayed by exposure to light or pushed forward by early artificial sunsets. In a series of behavioral experiments, treatment of corals with ionomycin or thapsigargin was found to delay broadcast spawning in M. franksi, demonstrating that pharmacologically altering cytoplasmic calcium levels generates the same response as light exposure. Together these results show that the photo-responsive cells of corals detect and respond to light by altering cytoplasmic calcium levels, similarly to the transduction pathways in complex invertebrate eyes. The primacy of cytoplasmic calcium levels in light responsivity has broad implications for coral reproduction, including predicting how different species spawn at different times after sunset and how reproductive isolation is achieved during coral speciation.
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Affiliation(s)
- J Daniel Hilton
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada
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Lapan SW, Reddien PW. Transcriptome analysis of the planarian eye identifies ovo as a specific regulator of eye regeneration. Cell Rep 2012; 2:294-307. [PMID: 22884275 DOI: 10.1016/j.celrep.2012.06.018] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 05/12/2012] [Accepted: 06/22/2012] [Indexed: 11/24/2022] Open
Abstract
Among the millions of invertebrate species with visual systems, the genetic basis of eye development and function is well understood only in Drosophila melanogaster. We describe an eye transcriptome for the planarian Schmidtea mediterranea. Planarian photoreceptors expressed orthologs of genes required for phototransduction and microvillus structure in Drosophila and vertebrates, and optic pigment cells expressed solute transporters and melanin synthesis enzymes similar to those active in the vertebrate retinal pigment epithelium. Orthologs of several planarian eye genes, such as bestrophin-1 and Usher syndrome genes, cause eye defects in mammals when perturbed and were not previously described to have roles in invertebrate eyes. Five previously undescribed planarian eye transcription factors were required for normal eye formation during head regeneration. In particular, a conserved, transcription-factor-encoding ovo gene was expressed from the earliest stages of eye regeneration and was required for regeneration of all cell types of the eye.
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Affiliation(s)
- Sylvain W Lapan
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
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Matsuyama T, Yamashita T, Imamoto Y, Shichida Y. Photochemical properties of mammalian melanopsin. Biochemistry 2012; 51:5454-62. [PMID: 22670683 DOI: 10.1021/bi3004999] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanopsin is the photoreceptor molecule of intrinsically photosensitive retinal ganglion cells, which serve as the input for various nonvisual behavior and physiological functions fundamental to organisms. The retina, therefore, possess a melanopsin-based nonvisual system in addition to the visual system based on the classical visual photoreceptor molecules. To elucidate the molecular properties of melanopsin, we have exogenously expressed mouse melanopsin in cultured cells. We were able to obtain large amounts of purified mouse melanopsin and conducted a comprehensive spectroscopic study of its photochemical properties. Melanopsin has an absorption maximum at 467 nm, and it converts to a meta intermediate having an absorption maximum at 476 nm. The melanopsin photoreaction is similar to that of squid rhodopsin, exhibiting bistability that results in a photosteady mixture of a resting state (melanopsin containing 11-cis-retinal) and an excited state (metamelanopsin containing all-trans-retinal) upon sustained irradiation. The absorption coefficient of melanopsin is 33000 ± 1000 M(-1) cm(-1), and its quantum yield of isomerization is 0.52; these values are also typical of invertebrate bistable pigments. Thus, the nonvisual system in the retina relies on a type of photoreceptor molecule different from that of the visual system. Additionally, we found a new state of melanopsin, containing 7-cis-retinal (extramelanopsin), which forms readily upon long-wavelength irradiation (yellow to red light) and photoconverts to metamelanopsin with short-wavelength (blue light) irradiation. Although it is unclear whether extramelanopsin would have any physiological role, it could potentially allow wavelength-dependent regulation of melanopsin functions.
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Affiliation(s)
- Take Matsuyama
- Department of Biophysics, Graduate School of Science, Kyoto University, Japan
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