1
|
Kumar D, Khan B, Okcay Y, Sis ÇÖ, Abdallah A, Murray F, Sharma A, Uemura M, Taliyan R, Heinbockel T, Rahman S, Goyal R. Dynamic endocannabinoid-mediated neuromodulation of retinal circadian circuitry. Ageing Res Rev 2024; 99:102401. [PMID: 38964508 DOI: 10.1016/j.arr.2024.102401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 06/05/2024] [Accepted: 06/28/2024] [Indexed: 07/06/2024]
Abstract
Circadian rhythms are biological rhythms that originate from the "master circadian clock," called the suprachiasmatic nucleus (SCN). SCN orchestrates the circadian rhythms using light as a chief zeitgeber, enabling humans to synchronize their daily physio-behavioral activities with the Earth's light-dark cycle. However, chronic/ irregular photic disturbances from the retina via the retinohypothalamic tract (RHT) can disrupt the amplitude and the expression of clock genes, such as the period circadian clock 2, causing circadian rhythm disruption (CRd) and associated neuropathologies. The present review discusses neuromodulation across the RHT originating from retinal photic inputs and modulation offered by endocannabinoids as a function of mitigation of the CRd and associated neuro-dysfunction. Literature indicates that cannabinoid agonists alleviate the SCN's ability to get entrained to light by modulating the activity of its chief neurotransmitter, i.e., γ-aminobutyric acid, thus preventing light-induced disruption of activity rhythms in laboratory animals. In the retina, endocannabinoid signaling modulates the overall gain of the retinal ganglion cells by regulating the membrane currents (Ca2+, K+, and Cl- channels) and glutamatergic neurotransmission of photoreceptors and bipolar cells. Additionally, endocannabinoids signalling also regulate the high-voltage-activated Ca2+ channels to mitigate the retinal ganglion cells and intrinsically photosensitive retinal ganglion cells-mediated glutamate release in the SCN, thus regulating the RHT-mediated light stimulation of SCN neurons to prevent excitotoxicity. As per the literature, cannabinoid receptors 1 and 2 are becoming newer targets in drug discovery paradigms, and the involvement of endocannabinoids in light-induced CRd through the RHT may possibly mitigate severe neuropathologies.
Collapse
Affiliation(s)
- Deepak Kumar
- Department of Neuropharmacology, School of Pharmaceutical Sciences, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India.
| | - Bareera Khan
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India
| | - Yagmur Okcay
- University of Health Sciences Gulhane Faculty of Pharmacy Department of Pharmacology, Turkey.
| | - Çağıl Önal Sis
- University of Health Sciences Gulhane Faculty of Pharmacy Department of Pharmacology, Turkey.
| | - Aya Abdallah
- Institute of Medical Science, University of Aberdeen, Aberdeen, Scotland.
| | - Fiona Murray
- Institute of Medical Science, University of Aberdeen, Aberdeen, Scotland.
| | - Ashish Sharma
- School of Medicine, Washington University, St. Louis, USA
| | - Maiko Uemura
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Rajeev Taliyan
- Department of Pharmacy, Birla Institute of Technology Science, Pilani, Rajasthan 333301, India.
| | - Thomas Heinbockel
- Howard University College of Medicine, Department of Anatomy, Washington, DC 20059, USA
| | - Shafiqur Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy South Dakota State University, Brookings, SD, USA.
| | - Rohit Goyal
- Department of Neuropharmacology, School of Pharmaceutical Sciences, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India.
| |
Collapse
|
2
|
Contreras E, Liang C, Mahoney HL, Javier JL, Luce ML, Labastida Medina K, Bozza T, Schmidt TM. Flp-recombinase mouse line for genetic manipulation of ipRGCs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.06.592761. [PMID: 38766000 PMCID: PMC11100754 DOI: 10.1101/2024.05.06.592761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Light has myriad impacts on behavior, health, and physiology. These signals originate in the retina and are relayed to the brain by more than 40 types of retinal ganglion cells (RGCs). Despite a growing appreciation for the diversity of RGCs, how these diverse channels of light information are ultimately integrated by the ~50 retinorecipient brain targets to drive these light-evoked effects is a major open question. This gap in understanding primarily stems from a lack of genetic tools that specifically label, manipulate, or ablate specific RGC types. Here, we report the generation and characterization of a new mouse line (Opn4FlpO), in which FlpO is expressed from the Opn4 locus, to manipulate the melanopsin-expressing, intrinsically photosensitive retinal ganglion cells. We find that the Opn4FlpO line, when crossed to multiple reporters, drives expression that is confined to ipRGCs and primarily labels the M1-M3 subtypes. Labeled cells in this mouse line show the expected intrinsic, melanopsin-based light response and morphological features consistent with the M1-M3 subtypes. In alignment with the morphological and physiological findings, we see strong innervation of non-image forming brain targets by ipRGC axons, and weaker innervation of image forming targets in Opn4FlpO mice labeled using AAV-based and FlpO-reporter lines. Consistent with the FlpO insertion disrupting the endogenous Opn4 transcript, we find that Opn4FlpO/FlpO mice show deficits in the pupillary light reflex, demonstrating their utility for behavioral research in future experiments. Overall, the Opn4FlpO mouse line drives Flp-recombinase expression that is confined to ipRGCs and most effectively drives recombination in M1-M3 ipRGCs. This mouse line will be of broad use to those interested in manipulating ipRGCs through a Flp-based recombinase for intersectional studies or in combination with other, non-Opn4 Cre driver lines.
Collapse
Affiliation(s)
- E Contreras
- Department of Neurobiology, Northwestern University, Evanston, IL
- Northwestern University Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, United States
| | - C Liang
- Department of Neurobiology, Northwestern University, Evanston, IL
| | - H L Mahoney
- Department of Neurobiology, Northwestern University, Evanston, IL
| | - J L Javier
- Department of Neurobiology, Northwestern University, Evanston, IL
| | - M L Luce
- Department of Neurobiology, Northwestern University, Evanston, IL
| | | | - T Bozza
- Department of Neurobiology, Northwestern University, Evanston, IL
| | - T M Schmidt
- Department of Neurobiology, Northwestern University, Evanston, IL
- Department of Ophthalmology, Feinberg School of Medicine, Chicago, IL
| |
Collapse
|
3
|
Abstract
Melanopsin is a light-activated G protein coupled receptor that is expressed widely across phylogeny. In mammals, melanopsin is found in intrinsically photosensitive retinal ganglion cells (ipRGCs), which are especially important for "non-image" visual functions that include the regulation of circadian rhythms, sleep, and mood. Photochemical and electrophysiological experiments have provided evidence that melanopsin has at least two stable conformations and is thus multistable, unlike the monostable photopigments of the classic rod and cone photoreceptors. Estimates of melanopsin's properties vary, challenging efforts to understand how the molecule influences vision. This article seeks to reconcile disparate views of melanopsin and offer a practical guide to melanopsin's complexities.
Collapse
Affiliation(s)
- Alan J. Emanuel
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA, USA
- Present address: Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Michael Tri H. Do
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA, USA
| |
Collapse
|
4
|
Karthikeyan R, Davies WI, Gunhaga L. Non-image-forming functional roles of OPN3, OPN4 and OPN5 photopigments. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2023. [DOI: 10.1016/j.jpap.2023.100177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
|
5
|
Liu A, Milner ES, Peng YR, Blume HA, Brown MC, Bryman GS, Emanuel AJ, Morquette P, Viet NM, Sanes JR, Gamlin PD, Do MTH. Encoding of environmental illumination by primate melanopsin neurons. Science 2023; 379:376-381. [PMID: 36701440 PMCID: PMC10445534 DOI: 10.1126/science.ade2024] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 11/21/2022] [Indexed: 01/27/2023]
Abstract
Light regulates physiology, mood, and behavior through signals sent to the brain by intrinsically photosensitive retinal ganglion cells (ipRGCs). How primate ipRGCs sense light is unclear, as they are rare and challenging to target for electrophysiological recording. We developed a method of acute identification within the live, ex vivo retina. Using it, we found that ipRGCs of the macaque monkey are highly specialized to encode irradiance (the overall intensity of illumination) by blurring spatial, temporal, and chromatic features of the visual scene. We describe mechanisms at the molecular, cellular, and population scales that support irradiance encoding across orders-of-magnitude changes in light intensity. These mechanisms are conserved quantitatively across the ~70 million years of evolution that separate macaques from mice.
Collapse
Affiliation(s)
- Andreas Liu
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA 02115, USA
| | - Elliott S. Milner
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA 02115, USA
- Present address: Sainsbury Wellcome Centre for Neural Circuits and Behavior, University College London, 25 Howland Street, London, W1T 4JG, UK
| | - Yi-Rong Peng
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
- Present address: Department of Ophthalmology, Stein Eye Institute, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Hannah A. Blume
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA 02115, USA
| | - Michael C. Brown
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA 02115, USA
| | - Gregory S. Bryman
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA 02115, USA
- Present address: Merck & Co., Inc., 320 Bent St, Cambridge, MA 02141, USA
| | - Alan J. Emanuel
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA 02115, USA
- Present address: Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA, 02115, USA
| | - Philippe Morquette
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA 02115, USA
| | - Nguyen-Minh Viet
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA 02115, USA
| | - Joshua R. Sanes
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Paul D. Gamlin
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Michael Tri H. Do
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children’s Hospital and Harvard Medical School. Boston, MA 02115, USA
| |
Collapse
|
6
|
McDowell RJ, Rodgers J, Milosavljevic N, Lucas RJ. Divergent G-protein selectivity across melanopsins from mice and humans. J Cell Sci 2022; 135:274359. [PMID: 35274137 PMCID: PMC8977054 DOI: 10.1242/jcs.258474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 02/07/2022] [Indexed: 11/21/2022] Open
Abstract
Melanopsin is an opsin photopigment and light-activated G-protein-coupled receptor; it is expressed in photoreceptive retinal ganglion cells (mRGCs) and can be employed as an optogenetic tool. Mammalian melanopsins can signal via Gq/11 and Gi/o/t heterotrimeric G proteins, but aspects of the mRGC light response appear incompatible with either mode of signalling. We use live-cell reporter assays in HEK293T cells to show that melanopsins from mice and humans can also signal via Gs. We subsequently show that this mode of signalling is substantially divergent between species. The two established structural isoforms of mouse melanopsin (which differ in the length of their C-terminal tail) both signalled strongly through all three G-protein classes (Gq/11, Gi/o and Gs), whereas human melanopsin showed weaker signalling through Gs. Our data identify Gs as a new mode of signalling for mammalian melanopsins and reveal diversity in G-protein selectivity across mammalian melanopsins. Summary: The photopigment melanopsin (OPN4), which provides inner retinal photoreception in mammals, shows light-dependent activation of Gs G protein that is more pronounced for mouse than human photopigment.
Collapse
Affiliation(s)
- Richard J McDowell
- Centre for Biological Timing, Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Jessica Rodgers
- Centre for Biological Timing, Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Nina Milosavljevic
- Centre for Biological Timing, Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Robert J Lucas
- Centre for Biological Timing, Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| |
Collapse
|
7
|
Phillips J, Muheim R, Painter M, Raines J, Anderson C, Landler L, Dommer D, Raines A, Deutschlander M, Whitehead J, Fitzpatrick NE, Youmans P, Borland C, Sloan K, McKenna K. Why is it so difficult to study magnetic compass orientation in murine rodents? J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:197-212. [PMID: 35094127 DOI: 10.1007/s00359-021-01532-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 01/21/2023]
Abstract
A magnetic compass sense has been demonstrated in all major classes of vertebrates, as well as in many invertebrates. In mammals, controlled laboratory studies of mice have provided evidence for a robust magnetic compass that is comparable to, or exceeds, the performance of that in other animals. Nevertheless, the vast majority of laboratory studies of spatial behavior and cognition in murine rodents have failed to produce evidence of sensitivity to magnetic cues. Given the central role that a magnetic compass sense plays in the spatial ecology and cognition of non-mammalian vertebrates, and the potential utility that a global/universal reference frame derived from the magnetic field would have in mammals, the question of why responses to magnetic cues have been so difficult to demonstrate reliably is of considerable importance. In this paper, we review evidence that the magnetic compass of murine rodents shares a number of properties with light-dependent compasses in a wide variety of other animals generally believed to be mediated by a radical pair mechanism (RPM) or related quantum process. Consistent with the RPM, we summarize both published and previously unpublished findings suggesting that the murine rodent compass is sensitive to low-level radio frequency (RF) fields. Finally, we argue that the presence of anthropogenic RF fields in laboratory settings, may be an important source of variability in responses of murine rodents to magnetic cues.
Collapse
Affiliation(s)
- John Phillips
- Dept of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061-0406, USA.
| | - Rachel Muheim
- Dept of Biology, Lund University, Biology Building, 223 62, Lund, Sweden
| | - Michael Painter
- Dept of Biology, Barry University, 11300 NE 2nd Ave, Miami, FL, 33161, USA
| | - Jenny Raines
- University of Virginia, 409 Lane Road, Charlottesville, VA, 22908, USA
| | - Chris Anderson
- Electrical Engineering Dept, US Naval Academy, 105 Maryland Ave, Annapolis, MD, 21402, USA
| | - Lukas Landler
- Institute of Zoology, University of Natural Resources and Life Sciences (BOKU), Gregor-Mendel-Straße 33/I, 1180, Vienna, Austria
| | - Dave Dommer
- University of Mount Olive, 5001 South Miami Boulevard, Durham, NC, 27703, USA
| | - Adam Raines
- Dept of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061-0406, USA
| | - Mark Deutschlander
- Dept of Biology, Hobart and William Smith Colleges, 300 Pulteney St., Geneva, NY, 14456, USA
| | - John Whitehead
- Dept of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061-0406, USA
| | | | - Paul Youmans
- Dept of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061-0406, USA
| | - Chris Borland
- Civic Champs, 642 N. Madison St., Suite 116, Bloomington, IN, 47404, USA
| | - Kelly Sloan
- Sanibel Captiva Conservation Foundation, 3333 Sanibel Captiva Rd, PO Box 839, Sanibel, FL, 33957, USA
| | - Kaitlyn McKenna
- Dept of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061-0406, USA
| |
Collapse
|
8
|
Ashton A, Foster RG, Jagannath A. Photic Entrainment of the Circadian System. Int J Mol Sci 2022; 23:ijms23020729. [PMID: 35054913 PMCID: PMC8775994 DOI: 10.3390/ijms23020729] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/17/2021] [Accepted: 12/22/2021] [Indexed: 01/27/2023] Open
Abstract
Circadian rhythms are essential for the survival of all organisms, enabling them to predict daily changes in the environment and time their behaviour appropriately. The molecular basis of such rhythms is the circadian clock, a self-sustaining molecular oscillator comprising a transcriptional–translational feedback loop. This must be continually readjusted to remain in alignment with the external world through a process termed entrainment, in which the phase of the master circadian clock in the suprachiasmatic nuclei (SCN) is adjusted in response to external time cues. In mammals, the primary time cue, or “zeitgeber”, is light, which inputs directly to the SCN where it is integrated with additional non-photic zeitgebers. The molecular mechanisms underlying photic entrainment are complex, comprising a number of regulatory factors. This review will outline the photoreception pathways mediating photic entrainment, and our current understanding of the molecular pathways that drive it in the SCN.
Collapse
|
9
|
Sheng Y, Chen L, Ren X, Jiang Z, Yau KW. Molecular determinants of response kinetics of mouse M1 intrinsically-photosensitive retinal ganglion cells. Sci Rep 2021; 11:23424. [PMID: 34873237 PMCID: PMC8648817 DOI: 10.1038/s41598-021-02832-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 11/19/2021] [Indexed: 11/28/2022] Open
Abstract
Intrinsically-photosensitive retinal ganglion cells (ipRGCs) are non-rod/non-cone retinal photoreceptors expressing the visual pigment, melanopsin, to detect ambient irradiance for various non-image-forming visual functions. The M1-subtype, amongst the best studied, mediates primarily circadian photoentrainment and pupillary light reflex. Their intrinsic light responses are more prolonged than those of rods and cones even at the single-photon level, in accordance with the typically slower time course of non-image-forming vision. The short (OPN4S) and long (OPN4L) alternatively-spliced forms of melanopsin proteins are both present in M1-ipRGCs, but their functional difference is unclear. We have examined this point by genetically removing the Opn4 gene (Opn4-/-) in mouse and re-expressing either OPN4S or OPN4L singly in Opn4-/- mice by using adeno-associated virus, but found no obvious difference in their intrinsic dim-flash responses. Previous studies have indicated that two dominant slow steps in M1-ipRGC phototransduction dictate these cells' intrinsic dim-flash-response kinetics, with time constants (τ1 and τ2) at room temperature of ~ 2 s and ~ 20 s, respectively. Here we found that melanopsin inactivation by phosphorylation or by β-arrestins may not be one of these two steps, because their genetic disruptions did not prolong the two time constants or affect the response waveform. Disruption of GAP (GTPase-Activating-Protein) activity on the effector enzyme, PLCβ4, in M1-ipRGC phototransduction to slow down G-protein deactivation also did not prolong the response decay, but caused its rising phase to become slightly sigmoidal by giving rise to a third time constant, τ3, of ~ 2 s (room temperature). This last observation suggests that GAP-mediated G-protein deactivation does partake in the flash-response termination, although normally with a time constant too short to be visible in the response waveform.
Collapse
Affiliation(s)
- Yanghui Sheng
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 725 North Wolfe St, Baltimore, MD, 21205, USA
- Graduate Neuroscience Program, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Lujing Chen
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 725 North Wolfe St, Baltimore, MD, 21205, USA
- Graduate Neuroscience Program, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave, Boston, MA, 02115, USA
| | - Xiaozhi Ren
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 725 North Wolfe St, Baltimore, MD, 21205, USA
- Vedere Bio II, Inc., 700 Main St, Cambridge, MA, 02139, USA
| | - Zheng Jiang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 725 North Wolfe St, Baltimore, MD, 21205, USA
- Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin St, Houston, TX, 77030, USA
| | - King-Wai Yau
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 725 North Wolfe St, Baltimore, MD, 21205, USA.
| |
Collapse
|
10
|
Contreras E, Nobleman AP, Robinson PR, Schmidt TM. Melanopsin phototransduction: beyond canonical cascades. J Exp Biol 2021; 224:273562. [PMID: 34842918 PMCID: PMC8714064 DOI: 10.1242/jeb.226522] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Melanopsin is a visual pigment that is expressed in a small subset of intrinsically photosensitive retinal ganglion cells (ipRGCs). It is involved in regulating non-image forming visual behaviors, such as circadian photoentrainment and the pupillary light reflex, while also playing a role in many aspects of image-forming vision, such as contrast sensitivity. Melanopsin was initially discovered in the melanophores of the skin of the frog Xenopus, and subsequently found in a subset of ganglion cells in rat, mouse and primate retinas. ipRGCs were initially thought to be a single retinal ganglion cell population, and melanopsin was thought to activate a single, invertebrate-like Gq/transient receptor potential canonical (TRPC)-based phototransduction cascade within these cells. However, in the 20 years since the discovery of melanopsin, our knowledge of this visual pigment and ipRGCs has expanded dramatically. Six ipRGC subtypes have now been identified in the mouse, each with unique morphological, physiological and functional properties. Multiple subtypes have also been identified in other species, suggesting that this cell type diversity is a general feature of the ipRGC system. This diversity has led to a renewed interest in melanopsin phototransduction that may not follow the canonical Gq/TRPC cascade in the mouse or in the plethora of other organisms that express the melanopsin photopigment. In this Review, we discuss recent findings and discoveries that have challenged the prevailing view of melanopsin phototransduction as a single pathway that influences solely non-image forming functions.
Collapse
Affiliation(s)
- Ely Contreras
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA,Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL 60208, USA
| | - Alexis P. Nobleman
- University of Maryland Baltimore County, Department of Biological Sciences, Baltimore, MD 21250, USA,Section on Light and Circadian Rhythms (SLCR), National Institute of Mental Health, NIH, Bethesda, MD 20892, USA
| | - Phyllis R. Robinson
- University of Maryland Baltimore County, Department of Biological Sciences, Baltimore, MD 21250, USA,Authors for correspondence (; )
| | - Tiffany M. Schmidt
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA,Department of Ophthalmology, Feinberg School of Medicine, Chicago, IL 60611, USA,Authors for correspondence (; )
| |
Collapse
|
11
|
Hannibal J. Comparative Neurology of Circadian Photoreception: The Retinohypothalamic Tract (RHT) in Sighted and Naturally Blind Mammals. Front Neurosci 2021; 15:640113. [PMID: 34054403 PMCID: PMC8160255 DOI: 10.3389/fnins.2021.640113] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/29/2021] [Indexed: 11/13/2022] Open
Abstract
The mammalian eye contains two systems for light perception: an image detecting system constituted primarily of the classical photoreceptors, rods and cones, and a non-image forming system (NIF) constituted of a small group of intrinsically photosensitive retinal ganglion cells driven by melanopsin (mRGCs). The mRGCs receive input from the outer retina and NIF mediates light entrainment of circadian rhythms, masking behavior, light induced inhibition of nocturnal melatonin secretion, pupillary reflex (PLR), and affect the sleep/wake cycle. This review focuses on the mammalian NIF and its anatomy in the eye as well as its neuronal projection to the brain. This pathway is known as the retinohypothalamic tract (RHT). The development and functions of the NIF as well as the knowledge gained from studying gene modified mice is highlighted. Furthermore, the similarities of the NIF between sighted (nocturnal and diurnal rodent species, monkeys, humans) and naturally blind mammals (blind mole rats Spalax ehrenbergi and the Iberian mole, Talpa occidentalis) are discussed in relation to a changing world where increasing exposure to artificial light at night (ALAN) is becoming a challenge for humans and animals in the modern society.
Collapse
Affiliation(s)
- Jens Hannibal
- Department of Clinical Biochemistry, Bispebjerg Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
12
|
Upton BA, Díaz NM, Gordon SA, Van Gelder RN, Buhr ED, Lang RA. Evolutionary Constraint on Visual and Nonvisual Mammalian Opsins. J Biol Rhythms 2021; 36:109-126. [PMID: 33765865 PMCID: PMC8058843 DOI: 10.1177/0748730421999870] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Animals have evolved light-sensitive G protein-coupled receptors, known as opsins, to detect coherent and ambient light for visual and nonvisual functions. These opsins have evolved to satisfy the particular lighting niches of the organisms that express them. While many unique patterns of evolution have been identified in mammals for rod and cone opsins, far less is known about the atypical mammalian opsins. Using genomic data from over 400 mammalian species from 22 orders, unique patterns of evolution for each mammalian opsins were identified, including photoisomerases, RGR-opsin (RGR) and peropsin (RRH), as well as atypical opsins, encephalopsin (OPN3), melanopsin (OPN4), and neuropsin (OPN5). The results demonstrate that OPN5 and rhodopsin show extreme conservation across all mammalian lineages. The cone opsins, SWS1 and LWS, and the nonvisual opsins, OPN3 and RRH, demonstrate a moderate degree of sequence conservation relative to other opsins, with some instances of lineage-specific gene loss. Finally, the photoisomerase, RGR, and the best-studied atypical opsin, OPN4, have high sequence diversity within mammals. These conservation patterns are maintained in human populations. Importantly, all mammalian opsins retain key amino acid residues important for conjugation to retinal-based chromophores, permitting light sensitivity. These patterns of evolution are discussed along with known functions of each atypical opsin, such as in circadian or metabolic physiology, to provide insight into the observed patterns of evolutionary constraint.
Collapse
Affiliation(s)
- Brian A. Upton
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
- Center for Chronobiology, Division of Pediatric Ophthalmology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
- Molecular & Developmental Biology Graduate Program, University of Cincinnati College of Medicine, Cincinnati, Ohio
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Nicolás M. Díaz
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, Washington
| | - Shannon A. Gordon
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, Washington
| | - Russell N. Van Gelder
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, Washington
- Departments of Biological Structure and Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington
| | - Ethan D. Buhr
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, Washington
| | - Richard A. Lang
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
- Center for Chronobiology, Division of Pediatric Ophthalmology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
- Department of Ophthalmology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| |
Collapse
|
13
|
Aranda ML, Schmidt TM. Diversity of intrinsically photosensitive retinal ganglion cells: circuits and functions. Cell Mol Life Sci 2021; 78:889-907. [PMID: 32965515 PMCID: PMC8650628 DOI: 10.1007/s00018-020-03641-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/10/2020] [Accepted: 09/03/2020] [Indexed: 12/25/2022]
Abstract
The melanopsin-expressing, intrinsically photosensitive retinal ganglion cells (ipRGCs) are a relatively recently discovered class of atypical ganglion cell photoreceptor. These ipRGCs are a morphologically and physiologically heterogeneous population that project widely throughout the brain and mediate a wide array of visual functions ranging from photoentrainment of our circadian rhythms, to driving the pupillary light reflex to improve visual function, to modulating our mood, alertness, learning, sleep/wakefulness, regulation of body temperature, and even our visual perception. The presence of melanopsin as a unique molecular signature of ipRGCs has allowed for the development of a vast array of molecular and genetic tools to study ipRGC circuits. Given the emerging complexity of this system, this review will provide an overview of the genetic tools and methods used to study ipRGCs, how these tools have been used to dissect their role in a variety of visual circuits and behaviors in mice, and identify important directions for future study.
Collapse
Affiliation(s)
- Marcos L Aranda
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Tiffany M Schmidt
- Department of Neurobiology, Northwestern University, Evanston, IL, USA.
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| |
Collapse
|
14
|
Photosensitive ganglion cells: A diminutive, yet essential population. ARCHIVOS DE LA SOCIEDAD ESPAÑOLA DE OFTALMOLOGÍA 2020; 96:299-315. [PMID: 34092284 DOI: 10.1016/j.oftale.2020.06.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 06/15/2020] [Indexed: 12/30/2022]
Abstract
Our visual system has evolved to provide us with an image of the scene that surrounds us, informing us of its texture, colour, movement, and depth with an enormous spatial and temporal resolution, and for this purpose, the image formation (IF) dedicates the vast majority of our retinal ganglion cell (RGC) population and much of our cerebral cortex. On the other hand, a minuscule proportion of RGCs, in addition to receiving information from classic cone and rod photoreceptors, express melanopsin and are intrinsically photosensitive (ipRGC). These ipRGC are dedicated to non-image-forming (NIF) visual functions, of which we are unaware, but which are essential for aspects related to our daily physiology, such as the timing of our circadian rhythms and our pupillary light reflex, among many others. Before the discovery of ipRGCs, it was thought that the IF and NIF functions were distinct compartments regulated by different RGCs, but this concept has evolved in recent years with the discovery of new types of ipRGCs that innervate subcortical IF regions, and therefore have IF visual functions. Six different types of ipRGCs are currently known. These are termed M1-M6, and differ in their morphological, functional, molecular properties, central projections, and visual behaviour responsibilities. A review is presented on the melanopsin visual system, the most active field of research in vision, for which knowledge has grown exponentially during the last two decades, when RGCs giving rise to this pathway were first discovered.
Collapse
|
15
|
Foster RG, Hughes S, Peirson SN. Circadian Photoentrainment in Mice and Humans. BIOLOGY 2020; 9:biology9070180. [PMID: 32708259 PMCID: PMC7408241 DOI: 10.3390/biology9070180] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/03/2020] [Accepted: 07/05/2020] [Indexed: 12/26/2022]
Abstract
Light around twilight provides the primary entrainment signal for circadian rhythms. Here we review the mechanisms and responses of the mouse and human circadian systems to light. Both utilize a network of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). In both species action spectra and functional expression of OPN4 in vitro show that melanopsin has a λmax close to 480 nm. Anatomical findings demonstrate that there are multiple pRGC sub-types, with some evidence in mice, but little in humans, regarding their roles in regulating physiology and behavior. Studies in mice, non-human primates and humans, show that rods and cones project to and can modulate the light responses of pRGCs. Such an integration of signals enables the rods to detect dim light, the cones to detect higher light intensities and the integration of intermittent light exposure, whilst melanopsin measures bright light over extended periods of time. Although photoreceptor mechanisms are similar, sensitivity thresholds differ markedly between mice and humans. Mice can entrain to light at approximately 1 lux for a few minutes, whilst humans require light at high irradiance (>100’s lux) and of a long duration (>30 min). The basis for this difference remains unclear. As our retinal light exposure is highly dynamic, and because photoreceptor interactions are complex and difficult to model, attempts to develop evidence-based lighting to enhance human circadian entrainment are very challenging. A way forward will be to define human circadian responses to artificial and natural light in the “real world” where light intensity, duration, spectral quality, time of day, light history and age can each be assessed.
Collapse
|
16
|
Valdez-Lopez JC, Gulati S, Ortiz EA, Palczewski K, Robinson PR. Melanopsin Carboxy-terminus phosphorylation plasticity and bulk negative charge, not strict site specificity, achieves phototransduction deactivation. PLoS One 2020; 15:e0228121. [PMID: 32236094 PMCID: PMC7112210 DOI: 10.1371/journal.pone.0228121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/06/2020] [Indexed: 11/19/2022] Open
Abstract
Melanopsin is a visual pigment expressed in a small subset of ganglion cells in the mammalian retina known as intrinsically photosensitive retinal ganglion cells (ipRGCs) and is implicated in regulating non-image forming functions such as circadian photoentrainment and pupil constriction and contrast sensitivity in image formation. Mouse melanopsin's Carboxy-terminus (C-terminus) possesses 38 serine and threonine residues, which can potentially serve as phosphorylation sites for a G-protein Receptor Kinase (GRK) and be involved in the deactivation of signal transduction. Previous studies suggest that S388, T389, S391, S392, S394, S395 on the proximal region of the C-terminus of mouse melanopsin are necessary for melanopsin deactivation. We expressed a series of mouse melanopsin C-terminal mutants in HEK293 cells and using calcium imaging, and we found that the necessary cluster of six serine and threonine residues, while being critical, are insufficient for proper melanopsin deactivation. Interestingly, the additional six serine and threonine residues adjacent to the required six sites, in either proximal or distal direction, are capable of restoring wild-type deactivation of melanopsin. These findings suggest an element of plasticity in the molecular basis of melanopsin phosphorylation and deactivation. In addition, C-terminal chimeric mutants and molecular modeling studies support the idea that the initial steps of deactivation and β-arrestin binding are centered around these critical phosphorylation sites (S388-S395). The degree of functional versatility described in this study, along with ipRGC biophysical heterogeneity and the possible use of multiple signal transduction cascades, might contribute to the diverse ipRGC light responses for use in non-image and image forming behaviors, even though all six sub types of ipRGCs express the same melanopsin gene OPN4.
Collapse
MESH Headings
- HEK293 Cells
- Humans
- Light Signal Transduction/physiology
- Models, Molecular
- Mutagenesis, Site-Directed
- Mutation
- Phosphorylation/physiology
- Protein Binding
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Rod Opsins/chemistry
- Rod Opsins/genetics
- Rod Opsins/metabolism
- Serine/genetics
- Serine/metabolism
- Threonine/genetics
- Threonine/metabolism
- beta-Arrestin 1/chemistry
- beta-Arrestin 1/metabolism
Collapse
Affiliation(s)
- Juan C. Valdez-Lopez
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| | - Sahil Gulati
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, California, United States of America
- Gatan Inc, Pleasanton, California, United States of America
| | - Elelbin A. Ortiz
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, California, United States of America
| | - Phyllis R. Robinson
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| |
Collapse
|
17
|
Sondereker KB, Stabio ME, Renna JM. Crosstalk: The diversity of melanopsin ganglion cell types has begun to challenge the canonical divide between image-forming and non-image-forming vision. J Comp Neurol 2020; 528:2044-2067. [PMID: 32003463 DOI: 10.1002/cne.24873] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 01/22/2020] [Accepted: 01/22/2020] [Indexed: 12/15/2022]
Abstract
Melanopsin ganglion cells have defied convention since their discovery almost 20 years ago. In the years following, many types of these intrinsically photosensitive retinal ganglion cells (ipRGCs) have emerged. In the mouse retina, there are currently six known types (M1-M6) of melanopsin ganglion cells, each with unique morphology, mosaics, connections, physiology, projections, and functions. While melanopsin-expressing cells are usually associated with behaviors like circadian photoentrainment and the pupillary light reflex, the characterization of multiple types has demonstrated a reach that may extend far beyond non-image-forming vision. In fact, studies have shown that individual types of melanopsin ganglion cells have the potential to impact image-forming functions like contrast sensitivity and color opponency. Thus, the goal of this review is to summarize the morphological and functional aspects of the six known types of melanopsin ganglion cells in the mouse retina and to highlight their respective roles in non-image-forming and image-forming vision. Although many melanopsin ganglion cell types do project to image-forming brain targets, it is important to note that this is only the first step in determining their influence on image-forming vision. Even so, the visual system has canonically been divided into these two functional realms and melanopsin ganglion cells have begun to challenge the boundary between them, providing an overlap of visual information that is complementary rather than redundant. Further studies on these ganglion cell photoreceptors will no doubt continue to illustrate an ever-expanding role for melanopsin ganglion cells in image-forming vision.
Collapse
Affiliation(s)
| | - Maureen E Stabio
- Department of Cell & Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
| | | |
Collapse
|
18
|
Do MTH. Melanopsin and the Intrinsically Photosensitive Retinal Ganglion Cells: Biophysics to Behavior. Neuron 2019; 104:205-226. [PMID: 31647894 PMCID: PMC6944442 DOI: 10.1016/j.neuron.2019.07.016] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/19/2019] [Accepted: 07/12/2019] [Indexed: 12/19/2022]
Abstract
The mammalian visual system encodes information over a remarkable breadth of spatiotemporal scales and light intensities. This performance originates with its complement of photoreceptors: the classic rods and cones, as well as the intrinsically photosensitive retinal ganglion cells (ipRGCs). IpRGCs capture light with a G-protein-coupled receptor called melanopsin, depolarize like photoreceptors of invertebrates such as Drosophila, discharge electrical spikes, and innervate dozens of brain areas to influence physiology, behavior, perception, and mood. Several visual responses rely on melanopsin to be sustained and maximal. Some require ipRGCs to occur at all. IpRGCs fulfill their roles using mechanisms that include an unusual conformation of the melanopsin protein, an extraordinarily slow phototransduction cascade, divisions of labor even among cells of a morphological type, and unorthodox configurations of circuitry. The study of ipRGCs has yielded insight into general topics that include photoreceptor evolution, cellular diversity, and the steps from biophysical mechanisms to behavior.
Collapse
Affiliation(s)
- Michael Tri H Do
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital and Harvard Medical School, Center for Life Science 12061, 3 Blackfan Circle, Boston, MA 02115, USA.
| |
Collapse
|
19
|
Lucas JA, Schmidt TM. Cellular properties of intrinsically photosensitive retinal ganglion cells during postnatal development. Neural Dev 2019; 14:8. [PMID: 31470901 PMCID: PMC6716945 DOI: 10.1186/s13064-019-0132-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/12/2019] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Melanopsin-expressing, intrinsically photosensitive retinal ganglion cells (ipRGCs) respond directly to light and have been shown to mediate a broad variety of visual behaviors in adult animals. ipRGCs are also the first light sensitive cells in the developing retina, and have been implicated in a number of retinal developmental processes such as pruning of retinal vasculature and refinement of retinofugal projections. However, little is currently known about the properties of the six ipRGC subtypes during development, and how these cells act to influence retinal development. We therefore sought to characterize the structure, physiology, and birthdate of the most abundant ipRGC subtypes, M1, M2, and M4, at discrete postnatal developmental timepoints. METHODS We utilized whole cell patch clamp to measure the electrophysiological and morphological properties of ipRGC subtypes through postnatal development. We also used EdU labeling to determine the embryonic timepoints at which ipRGC subtypes terminally differentiate. RESULTS Our data show that ipRGC subtypes are distinguishable from each other early in postnatal development. Additionally, we find that while ipRGC subtypes terminally differentiate at similar embryonic stages, the subtypes reach adult-like morphology and physiology at different developmental timepoints. CONCLUSIONS This work provides a broad assessment of ipRGC morphological and physiological properties during the postnatal stages at which they are most influential in modulating retinal development, and lays the groundwork for further understanding of the specific role of each ipRGC subtype in influencing retinal and visual system development.
Collapse
Affiliation(s)
- Jasmine A. Lucas
- Department of Neurobiology, Northwestern University, Evanston, IL USA
| | | |
Collapse
|
20
|
Rodgers J, Peirson SN, Hughes S, Hankins MW. Functional characterisation of naturally occurring mutations in human melanopsin. Cell Mol Life Sci 2018; 75:3609-3624. [PMID: 29700553 PMCID: PMC6133154 DOI: 10.1007/s00018-018-2813-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/06/2018] [Accepted: 04/05/2018] [Indexed: 12/12/2022]
Abstract
Melanopsin is a blue light-sensitive opsin photopigment involved in a range of non-image forming behaviours, including circadian photoentrainment and the pupil light response. Many naturally occurring genetic variants exist within the human melanopsin gene (OPN4), yet it remains unclear how these variants affect melanopsin protein function and downstream physiological responses to light. Here, we have used bioinformatic analysis and in vitro expression systems to determine the functional phenotypes of missense human OPN4 variants. From 1242 human OPN4 variants collated in the NCBI Short Genetic Variation database (dbSNP), we identified 96 that lead to non-synonymous amino acid substitutions. These 96 missense mutations were screened using sequence alignment and comparative approaches to select 16 potentially deleterious variants for functional characterisation using calcium imaging of melanopsin-driven light responses in HEK293T cells. We identify several previously uncharacterised OPN4 mutations with altered functional properties, including attenuated or abolished light responses, as well as variants demonstrating abnormal response kinetics. These data provide valuable insight into the structure-function relationships of human melanopsin, including several key functional residues of the melanopsin protein. The identification of melanopsin variants with significantly altered function may serve to detect individuals with disrupted melanopsin-based light perception, and potentially highlight those at increased risk of sleep disturbance, circadian dysfunction, and visual abnormalities.
Collapse
Affiliation(s)
- Jessica Rodgers
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Sir William Dunn School of Pathology, University of Oxford, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Sir William Dunn School of Pathology, University of Oxford, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Steven Hughes
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Sir William Dunn School of Pathology, University of Oxford, OMPI G, South Parks Road, Oxford, OX1 3RE, UK.
| | - Mark W Hankins
- Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Sir William Dunn School of Pathology, University of Oxford, OMPI G, South Parks Road, Oxford, OX1 3RE, UK.
| |
Collapse
|
21
|
Stachurska A, Sarna T. Regulation of Melanopsin Signaling: Key Interactions of the Nonvisual Photopigment. Photochem Photobiol 2018; 95:83-94. [DOI: 10.1111/php.12995] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/26/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Anna Stachurska
- Labolatory of Imaging and Force Spectroscopy; Malopolska Centre of Biotechnology; Jagiellonian University; Krakow Poland
| | - Tadeusz Sarna
- Department of Biophysics; Faculty of Biochemistry, Biophysics and Biotechnology; Jagiellonian University; Krakow Poland
| |
Collapse
|
22
|
Rodgers J, Hughes S, Pothecary CA, Brown LA, Hickey DG, Peirson SN, Hankins MW. Defining the impact of melanopsin missense polymorphisms using in vivo functional rescue. Hum Mol Genet 2018; 27:2589-2603. [PMID: 29718372 PMCID: PMC6048994 DOI: 10.1093/hmg/ddy150] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 04/11/2018] [Accepted: 04/16/2018] [Indexed: 12/02/2022] Open
Abstract
Melanopsin (OPN4) is an opsin photopigment expressed within intrinsically photosensitive retinal ganglion cells (ipRGCs) that mediate non-image forming (NIF) responses to light. Two single-nucleotide polymorphisms (SNPs) in human melanopsin (hOPN4), Pro10Leu and Thr394Ile, have recently been associated with abnormal NIF responses to light, including seasonal affective disorder. It has been suggested these behavioural changes are due to altered melanopsin signalling. However, there is currently no direct evidence to support this. Here we have used ipRGC-specific delivery of hOPN4 wild-type (WT), Pro10Leu or Thr394Ile adeno-associated viruses (AAV) to determine the functional consequences of hOPN4 SNPs on melanopsin-driven light responses and associated behaviours. Immunohistochemistry confirmed hOPN4 AAVs exclusively transduced mouse ipRGCs. Behavioural phenotyping performed before and after AAV injection demonstrated that both hOPN4 Pro10Leu and Thr394Ile could functionally rescue pupillary light responses and circadian photoentrainment in Opn4-/- mice, with no differences in NIF behaviours detected for animals expressing either SNP compared to hOPN4 WT. Multi-electrode array recordings revealed that ipRGCs expressing hOPN4 Thr394Ile exhibit melanopsin-driven light responses with significantly attenuated response amplitude, decreased sensitivity and faster offset kinetics compared to hOPN4 WT. IpRGCs expressing hOpn4 Pro10Leu also showed reduced response amplitude. Collectively these data suggest Thr394Ile and Pro10Leu may be functionally significant SNPs, which result in altered melanopsin signalling. To our knowledge, this study provides the first direct evidence for the effects of hOPN4 polymorphisms on melanopsin-driven light responses and NIF behaviours in vivo, providing further insight into the role of these SNPs in melanopsin function and human physiology.
Collapse
Affiliation(s)
- Jessica Rodgers
- Nuffield Department of Clinical Neurosciences, Sleep and Circadian Neuroscience Institute, OMPI G, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Steven Hughes
- Nuffield Department of Clinical Neurosciences, Sleep and Circadian Neuroscience Institute, OMPI G, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Carina A Pothecary
- Nuffield Department of Clinical Neurosciences, Sleep and Circadian Neuroscience Institute, OMPI G, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Laurence A Brown
- Nuffield Department of Clinical Neurosciences, Sleep and Circadian Neuroscience Institute, OMPI G, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Doron G Hickey
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Stuart N Peirson
- Nuffield Department of Clinical Neurosciences, Sleep and Circadian Neuroscience Institute, OMPI G, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Mark W Hankins
- Nuffield Department of Clinical Neurosciences, Sleep and Circadian Neuroscience Institute, OMPI G, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| |
Collapse
|
23
|
Kankanamge D, Ratnayake K, Samaradivakara S, Karunarathne A. Melanopsin (Opn4) utilizes Gα i and Gβγ as major signal transducers. J Cell Sci 2018; 131:jcs.212910. [PMID: 29712722 DOI: 10.1242/jcs.212910] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 04/23/2018] [Indexed: 01/16/2023] Open
Abstract
Melanopsin (Opn4), a ubiquitously expressed photoreceptor in all classes of vertebrates, is crucial for both visual and non-visual signaling. Opn4 supports visual functions of the eye by sensing radiance levels and discriminating contrast and brightness. Non-image-forming functions of Opn4 not only regulate circadian behavior, but also control growth and development processes of the retina. It is unclear how a single photoreceptor could govern such a diverse range of physiological functions; a role in genetic hardwiring could be one explanation, but molecular and mechanistic evidence is lacking. In addition to its role in canonical Gq pathway activation, here we demonstrate that Opn4 efficiently activates Gi heterotrimers and signals through the G protein βγ. Compared with the low levels of Gi pathway activation observed for several Gq-coupled receptors, the robust Gαi and Gβγ signaling of Opn4 led to both generation of PIP3 and directional migration of RAW264.7 macrophages. We propose that the ability of Opn4 to signal through Gαi and Gβγ subunits is a major contributor to its functional diversity.
Collapse
Affiliation(s)
- Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kasun Ratnayake
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Saroopa Samaradivakara
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| |
Collapse
|
24
|
Green CB. Circadian Posttranscriptional Regulatory Mechanisms in Mammals. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a030692. [PMID: 28778869 DOI: 10.1101/cshperspect.a030692] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The circadian clock drives rhythms in the levels of thousands of proteins in the mammalian cell, arising in part from rhythmic transcriptional regulation of the genes that encode them. However, recent evidence has shown that posttranscriptional processes also play a major role in generating the rhythmic protein makeup and ultimately the rhythmic physiology of the cell. Regulation of steps throughout the life of the messenger RNA (mRNA), ranging from initial mRNA processing and export from the nucleus to extensive control of translation and degradation in the cytosol have been shown to be important for producing the final rhythms in protein levels critical for proper circadian rhythmicity. These findings will be reviewed here.
Collapse
Affiliation(s)
- Carla B Green
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9111
| |
Collapse
|
25
|
Torres M, Becquet D, Franc JL, François-Bellan AM. Circadian processes in the RNA life cycle. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1467. [PMID: 29424086 DOI: 10.1002/wrna.1467] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 11/24/2017] [Accepted: 12/18/2017] [Indexed: 12/11/2022]
Abstract
The circadian clock drives daily rhythms of multiple physiological processes, allowing organisms to anticipate and adjust to periodic changes in environmental conditions. These physiological rhythms are associated with robust oscillations in the expression of at least 30% of expressed genes. While the ability for the endogenous timekeeping system to generate a 24-hr cycle is a cell-autonomous mechanism based on negative autoregulatory feedback loops of transcription and translation involving core-clock genes and their protein products, it is now increasingly evident that additional mechanisms also govern the circadian oscillations of clock-controlled genes. Such mechanisms can take place post-transcriptionally during the course of the RNA life cycle. It has been shown that many steps during RNA processing are regulated in a circadian manner, thus contributing to circadian gene expression. These steps include mRNA capping, alternative splicing, changes in splicing efficiency, and changes in RNA stability controlled by the tail length of polyadenylation or the use of alternative polyadenylation sites. RNA transport can also follow a circadian pattern, with a circadian nuclear retention driven by rhythmic expression within the nucleus of particular bodies (the paraspeckles) and circadian export to the cytoplasm driven by rhythmic proteins acting like cargo. Finally, RNA degradation may also follow a circadian pattern through the rhythmic involvement of miRNAs. In this review, we summarize the current knowledge of the post-transcriptional circadian mechanisms known to play a prominent role in shaping circadian gene expression in mammals. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Processing > RNA Editing and Modification RNA Export and Localization > Nuclear Export/Import.
Collapse
Affiliation(s)
- Manon Torres
- CNRS, CRN2M-UMR7286, Faculté de Médecine Nord, Aix-Marseille Université, Marseille, France
| | - Denis Becquet
- CNRS, CRN2M-UMR7286, Faculté de Médecine Nord, Aix-Marseille Université, Marseille, France
| | - Jean-Louis Franc
- CNRS, CRN2M-UMR7286, Faculté de Médecine Nord, Aix-Marseille Université, Marseille, France
| | | |
Collapse
|
26
|
Melanopsin mRNA in the Iris of Red-Eared Slider Turtles (Trachemys scripta elegans). J HERPETOL 2017. [DOI: 10.1670/16-046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
27
|
Milner ES, Do MTH. A Population Representation of Absolute Light Intensity in the Mammalian Retina. Cell 2017; 171:865-876.e16. [PMID: 28965762 PMCID: PMC6647834 DOI: 10.1016/j.cell.2017.09.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 08/02/2017] [Accepted: 09/01/2017] [Indexed: 12/12/2022]
Abstract
Environmental illumination spans many log units of intensity and is tracked for essential functions that include regulation of the circadian clock, arousal state, and hormone levels. Little is known about the neural representation of light intensity and how it covers the necessary range. This question became accessible with the discovery of mammalian photoreceptors that are required for intensity-driven functions, the M1 ipRGCs. The spike outputs of M1s are thought to uniformly track intensity over a wide range. We provide a different understanding: individual cells operate over a narrow range, but the population covers irradiances from moonlight to full daylight. The range of most M1s is limited by depolarization block, which is generally considered pathological but is produced intrinsically by these cells. The dynamics of block allow the population to code stimulus intensity with flexibility and efficiency. Moreover, although spikes are distorted by block, they are regularized during axonal propagation.
Collapse
Affiliation(s)
- Elliott Scott Milner
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital and Harvard Medical School, Center for Life Science 12061, Boston, MA 02115, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
| | - Michael Tri Hoang Do
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital and Harvard Medical School, Center for Life Science 12061, Boston, MA 02115, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
| |
Collapse
|
28
|
Abstract
In this issue of Neuron, Mure et al. (2016) demonstrate that two mechanisms-phosphorylation of a C-terminal intracellular region, and mechanism involving the whole of the C terminus-oppositely shape the kinetics and sensitivity of the nonvisual photoreceptor melanopsin.
Collapse
Affiliation(s)
- Russell N Van Gelder
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98104, USA; Department of Biological Structure, University of Washington School of Medicine, Seattle, WA 98104, USA; Department of Pathology, University of Washington School of Medicine, Seattle, WA 98104, USA.
| | - Ethan D Buhr
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98104, USA
| |
Collapse
|
29
|
Emanuel AJ, Kapur K, Do MTH. Biophysical Variation within the M1 Type of Ganglion Cell Photoreceptor. Cell Rep 2017; 21:1048-1062. [PMID: 29069587 PMCID: PMC5675019 DOI: 10.1016/j.celrep.2017.09.095] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 08/21/2017] [Accepted: 09/27/2017] [Indexed: 12/27/2022] Open
Abstract
Intrinsically photosensitive retinal ganglion cells of the M1 type encode environmental irradiance for functions that include circadian and pupillary regulation. Their distinct role, morphology, and molecular markers indicate that they are stereotyped circuit elements, but their physiological uniformity has not been investigated in a systematic fashion. We have profiled the biophysical parameters of mouse M1s and found that extreme variation is their hallmark. Most parameters span 1-3 log units, and the full range is evident in M1s that innervate brain regions serving divergent functions. Biophysical profiles differ among cells possessing similar morphology and between neighboring M1s recorded simultaneously. Variation in each parameter is largely independent of that in others, allowing for flexible individualization. Accordingly, a common stimulus drives heterogeneous spike outputs across cells. By contrast, a population of directionally selective retinal ganglion cells appeared physiologically uniform under similar conditions. Thus, M1s lack biophysical constancy and send diverse signals downstream.
Collapse
Affiliation(s)
- Alan J Emanuel
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Center for Life Science 12061, 3 Blackfan Circle, Boston, MA 02115, USA; Department of Neurology, Boston Children's Hospital and Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
| | - Kush Kapur
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Michael Tri H Do
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Center for Life Science 12061, 3 Blackfan Circle, Boston, MA 02115, USA; Department of Neurology, Boston Children's Hospital and Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
| |
Collapse
|
30
|
Hughes S, Foster RG, Peirson SN, Hankins MW. Expression and localisation of two-pore domain (K2P) background leak potassium ion channels in the mouse retina. Sci Rep 2017; 7:46085. [PMID: 28443635 PMCID: PMC5405414 DOI: 10.1038/srep46085] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/10/2017] [Indexed: 12/11/2022] Open
Abstract
Two-pore domain (K2P) potassium channels perform essential roles in neuronal function. These channels produce background leak type potassium currents that act to regulate resting membrane potential and levels of cellular excitability. 15 different K2P channels have been identified in mammals and these channels perform important roles in a wide number of physiological systems. However, to date there is only limited data available concerning the expression and role of K2P channels in the retina. In this study we conduct the first comprehensive study of K2P channel expression in the retina. Our data show that K2P channels are widely expressed in the mouse retina, with variations in expression detected at different times of day and throughout postnatal development. The highest levels of K2P channel expression are observed for Müller cells (TWIK-1, TASK-3, TRAAK, and TREK-2) and retinal ganglion cells (TASK-1, TREK-1, TWIK-1, TWIK-2 and TWIK-3). These data offer new insight into the channels that regulate the resting membrane potential and electrical activity of retinal cells, and suggests that K2P channels are well placed to act as central regulators of visual signalling pathways. The prominent role of K2P channels in neuroprotection offers novel avenues of research into the treatment of common retinal diseases.
Collapse
Affiliation(s)
- Steven Hughes
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Russell G. Foster
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Stuart N. Peirson
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Mark W. Hankins
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| |
Collapse
|
31
|
Peirson SN, Brown LA, Pothecary CA, Benson LA, Fisk AS. Light and the laboratory mouse. J Neurosci Methods 2017; 300:26-36. [PMID: 28414048 PMCID: PMC5909038 DOI: 10.1016/j.jneumeth.2017.04.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 02/06/2023]
Abstract
Light exerts widespread effects on physiology and behaviour. As well as the widely-appreciated role of light in vision, light also plays a critical role in many non-visual responses, including regulating circadian rhythms, sleep, pupil constriction, heart rate, hormone release and learning and memory. In mammals, responses to light are all mediated via retinal photoreceptors, including the classical rods and cones involved in vision as well as the recently identified melanopsin-expressing photoreceptive retinal ganglion cells (pRGCs). Understanding the effects of light on the laboratory mouse therefore depends upon an appreciation of the physiology of these retinal photoreceptors, including their differing sens itivities to absolute light levels and wavelengths. The signals from these photoreceptors are often integrated, with different responses involving distinct retinal projections, making generalisations challenging. Furthermore, many commonly used laboratory mouse strains carry mutations that affect visual or non-visual physiology, ranging from inherited retinal degeneration to genetic differences in sleep and circadian rhythms. Here we provide an overview of the visual and non-visual systems before discussing practical considerations for the use of light for researchers and animal facility staff working with laboratory mice.
Collapse
Affiliation(s)
- Stuart N Peirson
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom.
| | - Laurence A Brown
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom
| | - Carina A Pothecary
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom
| | - Lindsay A Benson
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom
| | - Angus S Fisk
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom
| |
Collapse
|
32
|
Esquiva G, Lax P, Pérez-Santonja JJ, García-Fernández JM, Cuenca N. Loss of Melanopsin-Expressing Ganglion Cell Subtypes and Dendritic Degeneration in the Aging Human Retina. Front Aging Neurosci 2017; 9:79. [PMID: 28420980 PMCID: PMC5378720 DOI: 10.3389/fnagi.2017.00079] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/14/2017] [Indexed: 01/07/2023] Open
Abstract
In mammals, melanopsin-expressing retinal ganglion cells (mRGCs) are, among other things, involved in several non-image-forming visual functions, including light entrainment of circadian rhythms. Considering the profound impact of aging on visual function and ophthalmic diseases, here we evaluate changes in mRGCs throughout the life span in humans. In 24 post-mortem retinas from anonymous human donors aged 10–81 years, we assessed the distribution, number and morphology of mRGCs by immunostaining vertical retinal sections and whole-mount retinas with antibodies against melanopsin. Human retinas showed melanopsin immunoreactivity in the cell body, axon and dendrites of a subset of ganglion cells at all ages tested. Nearly half of the mRGCs (51%) were located within the ganglion cell layer (GCL), and stratified in the outer (M1, 12%) or inner (M2, 16%) margin of the inner plexiform layer (IPL) or in both plexuses (M3, 23%). M1 and M2 cells conformed fairly irregular mosaics, while M3 cell distribution was slightly more regular. The rest of the mRGCs were more regularly arranged in the inner nuclear layer (INL) and stratified in the outer margin of the IPL (M1d, 49%). The quantity of each cell type decrease after age 70, when the total number of mRGCs was 31% lower than in donors aged 30–50 years. Moreover, in retinas with an age greater than 50 years, mRGCs evidenced a decrease in the dendritic area that was both progressive and age-dependent, as well as fewer branch points and terminal neurite tips per cell and a smaller Sholl area. After 70 years of age, the distribution profile of the mRGCs was closer to a random pattern than was observed in younger retinas. We conclude that advanced age is associated with a loss in density and dendritic arborization of the mRGCs in human retinas, possibly accounting for the more frequent occurrence of circadian rhythm disorders in elderly persons.
Collapse
Affiliation(s)
- Gema Esquiva
- Department of Physiology, Genetics and Microbiology, University of AlicanteAlicante, Spain
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of AlicanteAlicante, Spain.,Alicante Institute for Health and Biomedical Research (ISABIAL-FISABIO Foundation)Alicante, Spain
| | - Juan J Pérez-Santonja
- Alicante Institute for Health and Biomedical Research (ISABIAL-FISABIO Foundation)Alicante, Spain.,Department of Ophthalmology, Alicante University General HospitalAlicante, Spain
| | - José M García-Fernández
- Department of Morphology and Cellular Biology, Institute of Neuroscience Principado de Asturias (INEUROPA), University of OviedoOviedo, Spain
| | - Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of AlicanteAlicante, Spain.,Alicante Institute for Health and Biomedical Research (ISABIAL-FISABIO Foundation)Alicante, Spain.,Institute Ramón Margalef, University of AlicanteAlicante, Spain
| |
Collapse
|
33
|
Hannibal J, Christiansen AT, Heegaard S, Fahrenkrug J, Kiilgaard JF. Melanopsin expressing human retinal ganglion cells: Subtypes, distribution, and intraretinal connectivity. J Comp Neurol 2017; 525:1934-1961. [PMID: 28160289 DOI: 10.1002/cne.24181] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/24/2017] [Accepted: 01/25/2017] [Indexed: 12/15/2022]
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin belong to a heterogenic population of RGCs which regulate the circadian clock, masking behavior, melatonin suppression, the pupillary light reflex, and sleep/wake cycles. The different functions seem to be associated to different subtypes of melanopsin cells. In rodents, subtype classification has associated subtypes to function. In primate and human retina such classification has so far, not been applied. In the present study using antibodies against N- and C-terminal parts of human melanopsin, confocal microscopy and 3D reconstruction of melanopsin immunoreactive (-ir) RGCs, we applied the criteria used in mouse on human melanopsin-ir RGCs. We identified M1, displaced M1, M2, and M4 cells. We found two other subtypes of melanopsin-ir RGCs, which were named "gigantic M1 (GM1)" and "gigantic displaced M1 (GDM1)." Few M3 cells and no M5 subtypes were labeled. Total cell counts from one male and one female retina revealed that the human retina contains 7283 ± 237 melanopsin-ir (0.63-0.75% of the total number of RGCs). The melanopsin subtypes were unevenly distributed. Most significant was the highest density of M4 cells in the nasal retina. We identified input to the melanopsin-ir RGCs from AII amacrine cells and directly from rod bipolar cells via ribbon synapses in the innermost ON layer of the inner plexiform layer (IPL) and from dopaminergic amacrine cells and GABAergic processes in the outermost OFF layer of the IPL. The study characterizes a heterogenic population of human melanopsin-ir RGCs, which most likely are involved in different functions.
Collapse
Affiliation(s)
- Jens Hannibal
- Department of Clinical Biochemistry, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | | | - Steffen Heegaard
- Department of Ophalmology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Pathology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jan Fahrenkrug
- Department of Clinical Biochemistry, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Jens Folke Kiilgaard
- Department of Ophalmology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
34
|
Kato M, Sugiyama T, Sakai K, Yamashita T, Fujita H, Sato K, Tomonari S, Shichida Y, Ohuchi H. Two Opsin 3-Related Proteins in the Chicken Retina and Brain: A TMT-Type Opsin 3 Is a Blue-Light Sensor in Retinal Horizontal Cells, Hypothalamus, and Cerebellum. PLoS One 2016; 11:e0163925. [PMID: 27861495 PMCID: PMC5115664 DOI: 10.1371/journal.pone.0163925] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/17/2016] [Indexed: 01/15/2023] Open
Abstract
Opsin family genes encode G protein-coupled seven-transmembrane proteins that bind a retinaldehyde chromophore in photoreception. Here, we sought potential as yet undescribed avian retinal photoreceptors, focusing on Opsin 3 homologs in the chicken. We found two Opsin 3-related genes in the chicken genome: one corresponding to encephalopsin/panopsin (Opn3) in mammals, and the other belonging to the teleost multiple tissue opsin (TMT) 2 group. Bioluminescence imaging and G protein activation assays demonstrated that the chicken TMT opsin (cTMT) functions as a blue light sensor when forced-expressed in mammalian cultured cells. We did not detect evidence of light sensitivity for the chicken Opn3 (cOpn3). In situ hybridization demonstrated expression of cTMT in subsets of differentiating cells in the inner retina and, as development progressed, predominant localization to retinal horizontal cells (HCs). Immunohistochemistry (IHC) revealed cTMT in HCs as well as in small numbers of cells in the ganglion and inner nuclear layers of the post-hatch chicken retina. In contrast, cOpn3-IR cells were found in distinct subsets of cells in the inner nuclear layer. cTMT-IR cells were also found in subsets of cells in the hypothalamus. Finally, we found differential distribution of cOpn3 and cTMT proteins in specific cells of the cerebellum. The present results suggest that a novel TMT-type opsin 3 may function as a photoreceptor in the chicken retina and brain.
Collapse
Affiliation(s)
- Mutsuko Kato
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | | | - Kazumi Sakai
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Takahiro Yamashita
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Hirofumi Fujita
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Keita Sato
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Sayuri Tomonari
- Department of Life Systems, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
| | - Yoshinori Shichida
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Hideyo Ohuchi
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- * E-mail:
| |
Collapse
|
35
|
Aptel F, Weinreb RN, Chiquet C, Mansouri K. 24-h monitoring devices and nyctohemeral rhythms of intraocular pressure. Prog Retin Eye Res 2016; 55:108-148. [PMID: 27477112 DOI: 10.1016/j.preteyeres.2016.07.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 07/07/2016] [Accepted: 07/12/2016] [Indexed: 01/26/2023]
Abstract
Intraocular pressure (IOP) is not a fixed value and varies over both the short term and periods lasting several months or years. In particular, IOP is known to vary throughout the 24-h period of a day, defined as a nyctohemeral rhythm in humans. In clinical practice, it is crucial to evaluate the changes in IOP over 24 h in several situations, including the diagnosis of ocular hypertension and glaucoma (IOP is often higher at night) and to optimize the therapeutic management of glaucoma. Until recently, all evaluations of 24-h IOP rhythm were performed using repeated IOP measurements, requiring individuals to be awakened for nocturnal measurements. This method may be imperfect, because it is not physiologic and disturbs the sleep architecture, and also because it provides a limited number of time point measurements not sufficient to finely asses IOP changes. These limitations may have biased previous descriptions of physiological IOP rhythm. Recently, extraocular and intraocular devices integrating a pressure sensor for continuous IOP monitoring have been developed and are available for use in humans. The objective of this article is to present the contributions of these new 24-h monitoring devices for the study of the nyctohemeral rhythms. In healthy subjects and untreated glaucoma subjects, a nyctohemeral rhythm is consistently found and frequently characterized by a mean diurnal IOP lower than the mean nocturnal IOP, with a diurnal bathyphase - usually in the middle or at the end of the afternoon - and a nocturnal acrophase, usually in the middle or at the end of the night.
Collapse
Affiliation(s)
- Florent Aptel
- Inserm U1042, Hypoxia and Physiopathology Laboratory, University Grenoble Alpes, Grenoble, France; Department of Ophthalmology, University Hospital, CHU Grenoble, Grenoble, France
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Center and Department of Ophthalmology, University of California, San Diego, La Jolla, CA, USA
| | - Christophe Chiquet
- Inserm U1042, Hypoxia and Physiopathology Laboratory, University Grenoble Alpes, Grenoble, France; Department of Ophthalmology, University Hospital, CHU Grenoble, Grenoble, France
| | - Kaweh Mansouri
- Glaucoma Center, Montchoisi Clinic, Swiss Vision Network, Lausanne, Switzerland; Department of Ophthalmology, University of Colorado School of Medicine, Denver, CO, USA.
| |
Collapse
|
36
|
Kelley JL, Davies WIL. The Biological Mechanisms and Behavioral Functions of Opsin-Based Light Detection by the Skin. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00106] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
37
|
Kingston ACN, Cronin TW. Diverse Distributions of Extraocular Opsins in Crustaceans, Cephalopods, and Fish. Integr Comp Biol 2016; 56:820-833. [PMID: 27252200 DOI: 10.1093/icb/icw022] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Non-visual and extraocular photoreceptors are common among animals, but current understanding linking molecular pathways to physiological function of these receptors is lacking. Opsin diversity in extraocular tissues suggests that many putative extraocular photoreceptors utilize the "visual" phototransduction pathway-the same phototransduction pathway as photoreceptors within the retina dedicated to light detection for image sensing. Here, we provide a brief overview of the current understanding of non-visual and extraocular photoreceptors, and contribute a synopsis of several novel putative extraocular photoreceptors that use both visual and non-visual phototransduction pathways. Crayfish, cephalopods, and flat fish express opsins in diverse tissues, suggesting the presence of extraocular photoreceptors. In most cases, we find that these animals use the same phototransduction pathway that is utilized in the retinas for image-formation. However, we also find the presence of non-visual phototransduction components in the skin of flounders. Our evidence suggests that extraocular photoreceptors may employ a number of phototransduction pathways that do not appear to correlate with purpose or location of the photoreceptor.
Collapse
Affiliation(s)
- Alexandra C N Kingston
- Department of Biological Sciences, University of Maryland Baltimore County 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Thomas W Cronin
- Department of Biological Sciences, University of Maryland Baltimore County 1000 Hilltop Circle, Baltimore, MD 21250, USA
| |
Collapse
|
38
|
Shirzad-Wasei N, DeGrip WJ. Heterologous expression of melanopsin: Present, problems and prospects. Prog Retin Eye Res 2016; 52:1-21. [DOI: 10.1016/j.preteyeres.2016.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/25/2016] [Accepted: 02/01/2016] [Indexed: 12/12/2022]
|
39
|
Hughes S, Jagannath A, Rodgers J, Hankins MW, Peirson SN, Foster RG. Signalling by melanopsin (OPN4) expressing photosensitive retinal ganglion cells. Eye (Lond) 2016; 30:247-54. [PMID: 26768919 DOI: 10.1038/eye.2015.264] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 11/23/2015] [Indexed: 12/17/2022] Open
Abstract
Over the past two decades there have been significant advances in our understanding of both the anatomy and function of the melanopsin system. It has become clear that rather than acting as a simple irradiance detector the melanopsin system is in fact far more complicated. The range of behavioural systems known to be influenced by melanopsin activity is increasing with time, and it is now clear that melanopsin contributes not only to multiple non-image forming systems but also has a role in visual pathways. How melanopsin is capable of driving so many different behaviours is unclear, but recent evidence suggests that the answer may lie in the diversity of melanopsin light responses and the functional specialisation of photosensitive retinal ganglion cell (pRGC) subtypes. In this review, we shall overview the current understanding of the melanopsin system, and evaluate the evidence for the hypothesis that individual pRGC subtypes not only perform specific roles, but are functionally specialised to do so. We conclude that while, currently, the available data somewhat support this hypothesis, we currently lack the necessary detail to fully understand how the functional diversity of pRGC subtypes correlates with different behavioural responses, and ultimately why such complexity is required within the melanopsin system. What we are lacking is a cohesive understanding of how light responses differ between the pRGC subtypes (based not only on anatomical classification but also based on their site of innervation); how these diverse light responses are generated, and most importantly how these responses relate to the physiological functions they underpin.
Collapse
Affiliation(s)
- S Hughes
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - A Jagannath
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - J Rodgers
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - M W Hankins
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - S N Peirson
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - R G Foster
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| |
Collapse
|
40
|
Tsukamoto H, Kubo Y, Farrens DL, Koyanagi M, Terakita A, Furutani Y. Retinal Attachment Instability Is Diversified among Mammalian Melanopsins. J Biol Chem 2015; 290:27176-27187. [PMID: 26416885 DOI: 10.1074/jbc.m115.666305] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Indexed: 01/12/2023] Open
Abstract
Melanopsins play a key role in non-visual photoreception in mammals. Their close phylogenetic relationship to the photopigments in invertebrate visual cells suggests they have evolved to acquire molecular characteristics that are more suited for their non-visual functions. Here we set out to identify such characteristics by comparing the molecular properties of mammalian melanopsin to those of invertebrate melanopsin and visual pigment. Our data show that the Schiff base linking the chromophore retinal to the protein is more susceptive to spontaneous cleavage in mammalian melanopsins. We also find this stability is highly diversified between mammalian species, being particularly unstable for human melanopsin. Through mutagenesis analyses, we find that this diversified stability is mainly due to parallel amino acid substitutions in extracellular regions. We propose that the different stability of the retinal attachment in melanopsins may contribute to functional tuning of non-visual photoreception in mammals.
Collapse
Affiliation(s)
- Hisao Tsukamoto
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Okazaki, 444-8585, Japan,; Department of Structural Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan,.
| | - Yoshihiro Kubo
- Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan,; Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - David L Farrens
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239-3098
| | - Mitsumasa Koyanagi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Akihisa Terakita
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Yuji Furutani
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Okazaki, 444-8585, Japan,; Department of Structural Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| |
Collapse
|
41
|
Jagannath A, Hughes S, Abdelgany A, Pothecary CA, Di Pretoro S, Pires SS, Vachtsevanos A, Pilorz V, Brown LA, Hossbach M, MacLaren RE, Halford S, Gatti S, Hankins MW, Wood MJA, Foster RG, Peirson SN. Isoforms of Melanopsin Mediate Different Behavioral Responses to Light. Curr Biol 2015; 25:2430-4. [PMID: 26320947 PMCID: PMC4580334 DOI: 10.1016/j.cub.2015.07.071] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 05/18/2015] [Accepted: 07/30/2015] [Indexed: 12/05/2022]
Abstract
Melanopsin (OPN4) is a retinal photopigment that mediates a wide range of non-image-forming (NIF) responses to light including circadian entrainment, sleep induction, the pupillary light response (PLR), and negative masking of locomotor behavior (the acute suppression of activity in response to light). How these diverse NIF responses can all be mediated by a single photopigment has remained a mystery. We reasoned that the alternative splicing of melanopsin could provide the basis for functionally distinct photopigments arising from a single gene. The murine melanopsin gene is indeed alternatively spliced, producing two distinct isoforms, a short (OPN4S) and a long (OPN4L) isoform, which differ only in their C terminus tails. Significantly, both isoforms form fully functional photopigments. Here, we show that different isoforms of OPN4 mediate different behavioral responses to light. By using RNAi-mediated silencing of each isoform in vivo, we demonstrated that the short isoform (OPN4S) mediates light-induced pupillary constriction, the long isoform (OPN4L) regulates negative masking, and both isoforms contribute to phase-shifting circadian rhythms of locomotor behavior and light-mediated sleep induction. These findings demonstrate that splice variants of a single receptor gene can regulate strikingly different behaviors.
Collapse
Affiliation(s)
- Aarti Jagannath
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK; F. Hoffmann-La Roche AG, Pharma Research and Early Development, DTA Neuroscience pRED, Grenzacherstrasse 124, Basel 4070, Switzerland
| | - Steven Hughes
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK; F. Hoffmann-La Roche AG, Pharma Research and Early Development, DTA Neuroscience pRED, Grenzacherstrasse 124, Basel 4070, Switzerland
| | - Amr Abdelgany
- Department of Physiology, Anatomy and Genetics, South Parks Road, Oxford OX1 3QX, UK
| | - Carina A Pothecary
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
| | - Simona Di Pretoro
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
| | - Susana S Pires
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
| | - Athanasios Vachtsevanos
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
| | - Violetta Pilorz
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
| | - Laurence A Brown
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
| | - Markus Hossbach
- Axolabs GmbH, Fritz-Hornschuch-Straße 9, 95326 Kulmbach, Germany
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
| | - Silvia Gatti
- F. Hoffmann-La Roche AG, Pharma Research and Early Development, DTA Neuroscience pRED, Grenzacherstrasse 124, Basel 4070, Switzerland
| | - Mark W Hankins
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, South Parks Road, Oxford OX1 3QX, UK
| | - Russell G Foster
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK.
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, University of Oxford, Levels 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK.
| |
Collapse
|
42
|
Baker GE, de Grip WJ, Turton M, Wagner HJ, Foster RG, Douglas RH. Light sensitivity in a vertebrate mechanoreceptor? J Exp Biol 2015; 218:2826-9. [PMID: 26206352 PMCID: PMC4582172 DOI: 10.1242/jeb.125203] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/15/2015] [Indexed: 12/22/2022]
Abstract
Using immunohistochemistry and western blot analysis, we demonstrate that melanopsin is localised in cells around the central pore of lateral line neuromasts in the African clawed frog, Xenopus laevis. Since melanopsin is a known photoreceptor pigment with diverse functions in vertebrates, we suggest that the lateral line of Xenopus laevis, which is primarily a mechanoreceptor, might also be light sensitive. Potential functions of such photosensitivity are discussed, including its role in mediating locomotor responses following dermal illumination.
Collapse
Affiliation(s)
- Gary E Baker
- Department of Optometry & Visual Science, School of Health Sciences, City University London, Northampton Square, London EC1V 0HB, UK
| | - Willem J de Grip
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 HP Nijmegen, The Netherlands
| | - Michael Turton
- Nuffield Laboratory of Ophthalmology, University of Oxford, Levels 5-6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
| | - Hans-Joachim Wagner
- Anatomisches Institut, Universität Tübingen, Ősterbergstrasse 3, Tübingen 72074, Germany
| | - Russell G Foster
- Nuffield Laboratory of Ophthalmology, University of Oxford, Levels 5-6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
| | - Ron H Douglas
- Department of Optometry & Visual Science, School of Health Sciences, City University London, Northampton Square, London EC1V 0HB, UK
| |
Collapse
|
43
|
Co-expression of two subtypes of melatonin receptor on rat M1-type intrinsically photosensitive retinal ganglion cells. PLoS One 2015; 10:e0117967. [PMID: 25714375 PMCID: PMC4340921 DOI: 10.1371/journal.pone.0117967] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 12/15/2014] [Indexed: 12/15/2022] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) are involved in circadian and other non-image forming visual responses. An open question is whether the activity of these neurons may also be under the regulation mediated by the neurohormone melatonin. In the present work, by double-staining immunohistochemical technique, we studied the expression of MT1 and MT2, two known subtypes of mammalian melatonin receptors, in rat ipRGCs. A single subset of retinal ganglion cells labeled by the specific antibody against melanopsin exhibited the morphology typical of M1-type ipRGCs. Immunoreactivity for both MT1 and MT2 receptors was clearly seen in the cytoplasm of all labeled ipRGCs, indicating that these two receptors were co-expressed in each of these neurons. Furthermore, labeling for both the receptors were found in neonatal M1 cells as early as the day of birth. It is therefore highly plausible that retinal melatonin may directly modulate the activity of ipRGCs, thus regulating non-image forming visual functions.
Collapse
|
44
|
Hughes S, Jagannath A, Hankins MW, Foster RG, Peirson SN. Photic regulation of clock systems. Methods Enzymol 2014; 552:125-43. [PMID: 25707275 DOI: 10.1016/bs.mie.2014.10.018] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Circadian rhythms in physiology and behavior provide a selective advantage by enabling organisms to anticipate rhythmic changes in their environment. These rhythms are based upon a molecular clock generated via an intracellular transcriptional-translational feedback loop involving a number of key clock genes. However, to be of practical use, circadian rhythms need to be entrained to the external environment. In mammals, the primary signal for entrainment is light detected by the photoreceptors of the eye. Research on the mechanisms of photic entrainment has identified a novel photoreceptor system in the retina, consisting of photosensitive retinal ganglion cells expressing the photopigment melanopsin. Light input from these retinal photoreceptors reaches the master circadian pacemaker in the suprachiasmatic nuclei (SCN) via the retinohypothalamic tract, where it then interacts with the molecular clock to bring about entrainment. This chapter focuses on the retinal photoreceptors mediating entrainment, and how light information from the retina is transmitted to the SCN, before detailing recent advances in our understanding of how the molecular clock within the SCN is regulated by light input. Finally, the primary assays that have been used to measure photic entrainment are described.
Collapse
Affiliation(s)
- Steven Hughes
- Sleep and Circadian Institute (SCNi), Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Oxford, United Kingdom
| | - Aarti Jagannath
- Sleep and Circadian Institute (SCNi), Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Oxford, United Kingdom
| | - Mark W Hankins
- Sleep and Circadian Institute (SCNi), Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Oxford, United Kingdom
| | - Russell G Foster
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
| |
Collapse
|
45
|
Hannibal J, Kankipati L, Strang CE, Peterson BB, Dacey D, Gamlin PD. Central projections of intrinsically photosensitive retinal ganglion cells in the macaque monkey. J Comp Neurol 2014; 522:2231-48. [PMID: 24752373 DOI: 10.1002/cne.23588] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 12/16/2013] [Accepted: 01/27/2014] [Indexed: 12/23/2022]
Abstract
Circadian rhythms generated by the suprachiasmatic nucleus (SCN) are entrained to the environmental light/dark cycle via intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin and the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP). The ipRGCs regulate other nonimage-forming visual functions such as the pupillary light reflex, masking behavior, and light-induced melatonin suppression. To evaluate whether PACAP-immunoreactive retinal projections are useful as a marker for central projection of ipRGCs in the monkey brain, we characterized the occurrence of PACAP in melanopsin-expressing ipRGCs and in the retinal target areas in the brain visualized by the anterograde tracer cholera toxin subunit B (CtB) in combination with PACAP staining. In the retina, PACAP and melanopsin were found to be costored in 99% of melanopsin-expressing cells characterized as inner and outer stratifying melanopsin RGCs. Two macaque monkeys were anesthetized and received a unilateral intravitreal injection of CtB. Bilateral retinal projections containing colocalized CtB and PACAP immunostaining were identified in the SCN, the lateral geniculate complex including the pregeniculate nucleus, the pretectal olivary nucleus, the nucleus of the optic tract, the brachium of the superior colliculus, and the superior colliculus. In conclusion, PACAP-immunoreactive projections with colocalized CtB represent retinal projections of ipRGCs in the macaque monkey, supporting previous retrograde tracer studies demonstrating that melanopsin-containing retinal projections reach areas in the primate brain involved in both image- and nonimage-forming visual processing.
Collapse
Affiliation(s)
- J Hannibal
- Department of Clinical Biochemistry, Bispebjerg Hospital, DK2400, NV, Copenhagen, Denmark
| | | | | | | | | | | |
Collapse
|
46
|
A role for the outer retina in development of the intrinsic pupillary light reflex in mice. Neuroscience 2014; 286:60-78. [PMID: 25433236 DOI: 10.1016/j.neuroscience.2014.11.044] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 11/12/2014] [Accepted: 11/13/2014] [Indexed: 02/02/2023]
Abstract
Mice do not require the brain in order to maintain constricted pupils. However, little is known about this intrinsic pupillary light reflex (iPLR) beyond a requirement for melanopsin in the iris and an intact retinal ciliary marginal zone (CMZ). Here, we study the mouse iPLR in vitro and examine a potential role for outer retina (rods and cones) in this response. In wild-type mice the iPLR was absent at postnatal day 17 (P17), developing progressively from P21-P49. However, the iPLR only achieved ∼ 30% of the wild-type constriction in adult mice with severe outer retinal degeneration (rd and rdcl). Paradoxically, the iPLR increased significantly in retinal degenerate mice >1.5 years of age. This was accompanied by an increase in baseline pupil tone in the dark to levels indistinguishable from those in adult wild types. This rejuvenated iPLR response was slowed by atropine application, suggesting the involvement of cholinergic neurotransmission. We could find no evidence of an increase in melanopsin expression by quantitative PCR in the iris and ciliary body of aged retinal degenerates and a detailed anatomical analysis revealed a significant decline in melanopsin-positive intrinsically photosensitive retinal ganglion cells (ipRGCs) in rdcl mice >1.5 years. Adult mice lacking rod function (Gnat1(-/-)) also had a weak iPLR, while mice lacking functional cones (Cpfl5) maintained a robust response. We also identify an important role for pigmentation in the development of the mouse iPLR, with only a weak and transient response present in albino animals. Our results show that the iPLR in mice develops unexpectedly late and are consistent with a role for rods and pigmentation in the development of this response in mice. The enhancement of the iPLR in aged degenerate mice was extremely surprising but may have relevance to behavioral observations in mice and patients with retinitis pigmentosa.
Collapse
|
47
|
Nadal-Nicolás FM, Salinas-Navarro M, Jiménez-López M, Sobrado-Calvo P, Villegas-Pérez MP, Vidal-Sanz M, Agudo-Barriuso M. Displaced retinal ganglion cells in albino and pigmented rats. Front Neuroanat 2014; 8:99. [PMID: 25339868 PMCID: PMC4186482 DOI: 10.3389/fnana.2014.00099] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 09/04/2014] [Indexed: 01/30/2023] Open
Abstract
We have studied in parallel the population of displaced retinal ganglion cells (dRGCs) and normally placed (orthotopic RGCs, oRGCs) in albino and pigmented rats. Using retrograde tracing from the optic nerve, from both superior colliculi (SC) or from the ipsilateral SC in conjunction with Brn3 and melanopsin immunodetection, we report for the first time their total number and topography as well as the number and distribution of those dRGCs and oRGCs that project ipsi- or contralaterally and/or that express any of the three Brn3 isoforms or melanopsin. The total number of RGCs (oRGCs+dRGCs) is 84,706 ± 1249 in albino and 90,440 ± 2236 in pigmented, out of which 2383 and 2428 are melanopsin positive (m-RGCs), respectively. Regarding dRGCs: i/ albino rats have a significantly lower number of dRGCs than pigmented animals (0.5% of the total number of RGCs vs. 2.5%, respectively), ii/ dRGCs project massively to the contralateral SC, iii/ the percentage of ipsilaterality is higher for dRGCs than for oRGCs, iv/ a higher proportion of ipsilateral dRGCs is observed in albino than pigmented animals, v/ dRGC topography is very specific, they predominate in the equatorial temporal retina, being densest where the oRGCs are densest, vi/ Brn3a detects all dRGCs except half of the ipsilateral ones and those that express melanopsin, vii/ the proportion of dRGCs that express Brn3b or Brn3c is slightly lower than in the oRGC population, viii/ a higher percentage of dRGCs (13% albino, 9% pigmented) than oRGCs (2.6%) express melanopsin, ix/ few m-RGCs (displaced and orthotopic) project to the ipsilateral SC, x/ the topography of m-dRGCs does not resemble the general distribution of dRGCs, xi/ The soma size in m-oRGCs ranges from 10 to 21 μm and in m-dRGCs from 8 to 15 μm, xii/ oRGCs and dRGCs have the same susceptibility to axonal injury and ocular hypertension. Although the role of mammalian dRGCs remains to be determined, our data suggest that they are not misplaced by an ontogenic mistake.
Collapse
Affiliation(s)
- Francisco M Nadal-Nicolás
- Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca Murcia, Spain ; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia Murcia, Spain ; Hospital Clínico Universitario Virgen de la Arrixaca Murcia, Spain
| | - Manuel Salinas-Navarro
- Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca Murcia, Spain ; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia Murcia, Spain
| | - Manuel Jiménez-López
- Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca Murcia, Spain ; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia Murcia, Spain
| | - Paloma Sobrado-Calvo
- Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca Murcia, Spain ; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia Murcia, Spain
| | - María P Villegas-Pérez
- Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca Murcia, Spain ; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia Murcia, Spain
| | - Manuel Vidal-Sanz
- Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca Murcia, Spain ; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia Murcia, Spain
| | - Marta Agudo-Barriuso
- Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca Murcia, Spain ; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia Murcia, Spain ; Hospital Clínico Universitario Virgen de la Arrixaca Murcia, Spain
| |
Collapse
|
48
|
Georg B, Rask L, Hannibal J, Fahrenkrug J. The Light-InducedFOSResponse in Melanopsin Expressing HEK-293 Cells is Correlated with Melanopsin Quantity and Dependent on Light Duration and Irradiance. Photochem Photobiol 2014; 90:1069-76. [DOI: 10.1111/php.12298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 05/29/2014] [Indexed: 01/26/2023]
Affiliation(s)
- Birgitte Georg
- Department of Clinical Biochemistry; Faculty of Health Sciences; Bispebjerg Hospital; University of Copenhagen; Copenhagen NV Denmark
| | - Lene Rask
- Department of Clinical Biochemistry; Faculty of Health Sciences; Bispebjerg Hospital; University of Copenhagen; Copenhagen NV Denmark
| | - Jens Hannibal
- Department of Clinical Biochemistry; Faculty of Health Sciences; Bispebjerg Hospital; University of Copenhagen; Copenhagen NV Denmark
| | - Jan Fahrenkrug
- Department of Clinical Biochemistry; Faculty of Health Sciences; Bispebjerg Hospital; University of Copenhagen; Copenhagen NV Denmark
| |
Collapse
|
49
|
Hughes S, Jagannath A, Hickey D, Gatti S, Wood M, Peirson SN, Foster RG, Hankins MW. Using siRNA to define functional interactions between melanopsin and multiple G Protein partners. Cell Mol Life Sci 2014; 72:165-79. [PMID: 24958088 PMCID: PMC4282707 DOI: 10.1007/s00018-014-1664-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 05/10/2014] [Accepted: 06/02/2014] [Indexed: 12/13/2022]
Abstract
Melanopsin expressing photosensitive retinal ganglion cells (pRGCs) represent a third class of ocular photoreceptors and mediate a range of non-image forming responses to light. Melanopsin is a G protein coupled receptor (GPCR) and existing data suggest that it employs a membrane bound signalling cascade involving Gnaq/11 type G proteins. However, to date the precise identity of the Gα subunits involved in melanopsin phototransduction remains poorly defined. Here we show that Gnaq, Gna11 and Gna14 are highly co-expressed in pRGCs of the mouse retina. Furthermore, using RNAi based gene silencing we show that melanopsin can signal via Gnaq, Gna11 or Gna14 in vitro, and demonstrate that multiple members of the Gnaq/11 subfamily, including Gna14 and at least Gnaq or Gna11, can participate in melanopsin phototransduction in vivo and contribute to the pupillary light responses of mice lacking rod and cone photoreceptors. This diversity of G protein interactions suggests additional complexity in the melanopsin phototransduction cascade and may provide a basis for generating the diversity of light responses observed from pRGC subtypes.
Collapse
Affiliation(s)
- Steven Hughes
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, OX3 9DU UK
| | - Aarti Jagannath
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, OX3 9DU UK
- F. Hoffman La Roche, RED Research and Development, CNS DTA, Basel, Switzerland
| | - Doron Hickey
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, OX3 9DU UK
| | - Silvia Gatti
- F. Hoffman La Roche, RED Research and Development, CNS DTA, Basel, Switzerland
| | - Matthew Wood
- Department of Anatomy, Physiology and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, OX1 3QX UK
| | - Stuart N. Peirson
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, OX3 9DU UK
| | - Russell G. Foster
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, OX3 9DU UK
| | - Mark W. Hankins
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, OX3 9DU UK
| |
Collapse
|
50
|
Hannibal J, Kankipati L, Strang C, Peterson B, Dacey D, Gamlin P. Central projections of intrinsically photosensitive retinal ganglion cells in the macaque monkey. J Comp Neurol 2014. [DOI: 10.1002/cne.23555] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- J. Hannibal
- Department of Clinical Biochemistry; Bispebjerg Hospital; DK2400, NV Copenhagen Denmark
| | - L. Kankipati
- Department of Ophthalmology; University of Alabama at Birmingham; Birmingham Alabama 35233
| | - C.E. Strang
- Department of Vision Sciences; University of Alabama at Birmingham; Birmingham Alabama 35233
| | - B.B. Peterson
- Department of Biological Structure and the National Primate Research Center; University of Washington; Seattle Washington 98195
| | - D. Dacey
- Department of Biological Structure and the National Primate Research Center; University of Washington; Seattle Washington 98195
| | - P.D. Gamlin
- Department of Ophthalmology; University of Alabama at Birmingham; Birmingham Alabama 35233
| |
Collapse
|