1
|
Ziółkowska N, Lewczuk B, Szyryńska N, Rawicka A, Vyniarska A. Low-Intensity Blue Light Exposure Reduces Melanopsin Expression in Intrinsically Photosensitive Retinal Ganglion Cells and Damages Mitochondria in Retinal Ganglion Cells in Wistar Rats. Cells 2023; 12:cells12071014. [PMID: 37048087 PMCID: PMC10093228 DOI: 10.3390/cells12071014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/18/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023] Open
Abstract
This study investigated the effect of low-intensity blue light on the albino Wistar rat retina, including intrinsically photosensitive retinal ganglion cells (ipRGCs). Three groups of nine albino Wistar rats were used. One group was continuously exposed to blue light (150 lx) for 2 d (STE); one was exposed to 12 h of blue light and 12 h of darkness for 10 d (LTE); one was maintained in 12 h of white light (150 lx) and 12 h of darkness for 10 d (control). Melanopsin (Opn4) was immunolabelled on retinal whole-mounts. To count and measure Opn4-positive ipRGC somas and dendrites (including Sholl profiles), Neuron J was used. Retinal cryosections were immunolabeled for glial fibrillary acid protein (GFAP) and with terminal deoxynucleotidyl transferase dUTP nick-end labelling for apoptosis detection. LTE reduced the length of Opn4-positive ipRGC dendrites (p = 0.03) and decreased Opn4-immunoreactivity in ipRGC outer stratifying dendrites. LTE and STE decreased the complexity of dendritic arborization (Sholl profile; p < 0.001, p = 0.03, respectively), increased retinal GFAP immunoreactivity (p < 0.001, p = 0.002, respectively), and caused outer segment vesiculation and outer nuclear layer apoptosis. Ultrastructural analysis showed that LTE damaged mitochondria in retinal ganglion cells and in the inner plexiform layer. Thus, LTE to low-intensity blue light harms the retinas of albino Wistar rats.
Collapse
|
2
|
Ziólkowska N, Chmielewska-Krzesinska M, Vyniarska A, Sienkiewicz W. Exposure to Blue Light Reduces Melanopsin Expression in Intrinsically Photoreceptive Retinal Ganglion Cells and Damages the Inner Retina in Rats. Invest Ophthalmol Vis Sci 2022; 63:26. [PMID: 35060997 PMCID: PMC8787613 DOI: 10.1167/iovs.63.1.26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Purpose The purpose of this study was to investigative the effects of blue light on intrinsically photoreceptive retinal ganglion cells (ipRGCs). Methods Brown Norway rats were used. Nine rats were continuously exposed to blue light (light emitting diodes [LEDs]: 463 nm; 1000 lx) for 2 days (acute exposure [AE]); 9 rats were exposed to 12 hours of blue light and 12 hours of darkness for 10 days (long-term exposure [LTE]); 6 control rats were exposed to 12 hours of white fluorescent light (1000 lx) and 12 hours of darkness for 10 days. Whole-mount retinas were immunolabelled with melanopsin antibodies; melanopsin-positive (MP) ipRGC somas and processes were counted and measured with Neuron J. To detect apoptosis, retinal cryo-sections were stained with terminal deoxynucleotidyl transferase dUTP nick-end labeling. Ultra-thin sections were visualized with transmission electron microscopy. Results The number of MP ipRGC somas was significantly lower in retinas from AE and LTE rats than in those from control rats (P < 0.001 and = 0.002, respectively). The mean length of MP areas of processes was significantly lower in AE rats (P < 0.001). AE rats had severe retinal damage and massive apoptosis in the outer nuclear layer; their mitochondria were damaged in the axons and dendrites of the nerve fiber layer and the inner plexiform layer. Retinal ganglion cells (RGCs) in AE rats appeared to have reduced amounts of free ribosomes and rough endoplasmic reticulum. Conclusions AE to blue light reduces melanopsin expression and damages RGCs, likely including ipRGCs. Changes in the axons and dendrites of RGCs suggest possible disruption of intraretinal and extraretinal signal transmission.
Collapse
Affiliation(s)
- Natalia Ziólkowska
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Malgorzata Chmielewska-Krzesinska
- Department of Pathophysiology, Forensic Veterinary and Administration, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Alla Vyniarska
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Stepan Gzhytskyi National University of Veterinary and Biotechnologies, Lviv, Ukraine
| | - Waldemar Sienkiewicz
- Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| |
Collapse
|
3
|
Geng AL, Zhang J, Zhang Y, Wang HH, Chu Q, Yan ZX, Liu HG. Effects of lighting regimes on performance, pineal melanopsin expression and melatonin content in native laying hens aged from 19 to 34 weeks. Poult Sci 2021; 101:101567. [PMID: 34823188 PMCID: PMC8626689 DOI: 10.1016/j.psj.2021.101567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/09/2021] [Accepted: 10/21/2021] [Indexed: 11/28/2022] Open
Abstract
Melanopsin, a key light sensitive pigment, plays an important role in the regulation of bio-rhythm and photo-adaptation in poultry. This study aimed to investigate the effects of different lighting regimes on performance, pineal melanopsin expression and melatonin content in a native chicken, Beijing You Chicken (BYC) aged from 19 to 34 wk. A total of 900 nineteen-wk-old BYC female chicken having no significant body weight differences were randomly allocated to 3 groups with 3 replicates each, 100 birds each replicate, reared in individually lit floor pens with separate outdoor areas. Three different lighting regimes were used, including continuous 16 h (16L:8D, 6:00–22:00) for group 1, intermittent 16 h (12L:2D:4L:6D, 6:00–18:00, 20:00–24:00) for group 2, and continuous 12 h (12L:12D, 6:00–18:00) for group 3, respectively. The performance was measured for 19 to 34 wk. Serum melatonin (Mel), prolactin (Prl), luteinizing hormone (LH), and 17-beta estradiol (E2) contents were measured at 24 wk, 29 wk, and 34 wk of age, the relative expression of pineal melanopsin gene (Opn4 mRNA) was measured on 1 d at 9:00, 13:00, 17:00, 21:00, 1:00, and 5:00 at 29 wk of age, and at the end of 29 wk and 34 wk. The results showed that the egg mass, egg-laying rate, and feed egg ratio of BYC were not affected by lighting regimes for 19 to 34 wk (P > 0.05), except for the average feed intake (AFI) (P < 0.05). The AFI in the 12L:12D group was significantly higher than that in the 16L:8D group (P < 0.05), but had no difference with that in the 12L:2D:4L:6D group. The pineal Opn4 mRNA level was significantly upregulated in the 12L:2D:4L:6D group and downregulated in the 12L:12D group when compared with 16L:8D group at 29 and 34 wks of age (P < 0.05). The Mel content in the 16L:8D group was lower than that in the other 2 groups at 29 wk of age (P < 0.05), there was no difference in Mel content between 16L:8D group and 12L:2D:4L:6D group at 34 wk of age (P > 0.05). The present study suggested that the pineal melanopsin expression of the birds in the intermittent 16 h lighting group was higher than in the continuous 16 h and 12 h lighting group, and a significant negative correlation was found between melanopsin expression and Mel content at 34 wk of age, which may interact to promote the photo-adaptation of the native chicken and affect the future laying performance.
Collapse
Affiliation(s)
- A L Geng
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, P. R. China.
| | - J Zhang
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, P. R. China
| | - Y Zhang
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, P. R. China
| | - H H Wang
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, P. R. China
| | - Q Chu
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, P. R. China
| | - Z X Yan
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, P. R. China
| | - H G Liu
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, P. R. China
| |
Collapse
|
4
|
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
|
5
|
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: 3] [Impact Index Per Article: 0.8] [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
|
6
|
Sheng W, Jin M, Pan G, Weng S, Sik A, Han L, Liu K. Cellular localization of melatonin receptor Mel1b in pigeon retina. Neuropeptides 2019; 78:101974. [PMID: 31645269 DOI: 10.1016/j.npep.2019.101974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/10/2019] [Accepted: 09/22/2019] [Indexed: 12/15/2022]
Abstract
Melatonin, an important neuromodulator involved in circadian rhythms, modulates a series of physiological processes via activating its specific receptors, namely Mel1a (MT1), Mel1b (MT2) and Mel1c receptors. In this work, the localization of Mel1b receptor was studied in pigeon retina using double immunohistochemistry staining and confocal scanning microscopy. Our results showed that Mel1b receptor widely existed in the outer segment of photoreceptors and in the somata of dopaminergic amacrine cells, cholinergic amacrine cells, glycinergic AII amacrine cells, conventional ganglion cells and intrinsically photosensitive retinal ganglion cells, while horizontal cells, bipolar cells and Müller glial cells seemed to lack immunoreactivity of Mel1b receptor. That multiple types of retinal cells expressing Mel1b receptor suggests melatonin may directly modulate the activities of retina via activating Mel1b receptor.
Collapse
Affiliation(s)
- Wenlong Sheng
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China.
| | - Meng Jin
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Ge Pan
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Shijun Weng
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Attila Sik
- Institute of Transdisciplinary Discoveries, University of Pecs, Pecs, Hungary; Institute of Physiology, Medical School, University of Pecs, Pecs, Hungary; Szentagothai Research Centre, University of Pecs, Pecs, Hungary; Medical School, University of Birmingham, Birmingham, UK
| | - Liwen Han
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Kechun Liu
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China.
| |
Collapse
|
7
|
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
|
8
|
Benedetto MM, Guido ME, Contin MA. Non-Visual Photopigments Effects of Constant Light-Emitting Diode Light Exposure on the Inner Retina of Wistar Rats. Front Neurol 2017; 8:417. [PMID: 28871236 PMCID: PMC5566984 DOI: 10.3389/fneur.2017.00417] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 07/31/2017] [Indexed: 12/31/2022] Open
Abstract
The retina is part of the central nervous system specially adapted to capture light photons and transmit this information to the brain through photosensitive retinal cells involved in visual and non-visual activities. However, excessive light exposure may accelerate genetic retinal diseases or induce photoreceptor cell (PRC) death, finally leading to retinal degeneration (RD). Light pollution (LP) caused by the characteristic use of artificial light in modern day life may accelerate degenerative diseases or promote RD and circadian desynchrony. We have developed a working model to study RD mechanisms in a low light environment using light-emitting diode (LED) sources, at constant or long exposure times under LP conditions. The mechanism of PRC death is still not fully understood. Our main goal is to study the biochemical mechanisms of RD. We have previously demonstrated that constant light (LL) exposure to white LED produces a significant reduction in the outer nuclear layer (ONL) by classical PRC death after 7 days of LL exposure. The PRCs showed TUNEL-positive labeling and a caspase-3-independent mechanism of cell death. Here, we investigate whether constant LED exposure affects the inner-retinal organization and structure, cell survival and the expression of photopigments; in particular we look into whether constant LED exposure causes the death of retinal ganglion cells (RGCs), of intrinsically photosensitive RGCs (ipRGCs), or of other inner-retinal cells. Wistar rats exposed to 200 lx of LED for 2 to 8 days (LL 2 and LL 8) were processed for histological and protein. The results show no differences in the number of nucleus or TUNEL positive RGCs nor inner structural damage in any of LL groups studied, indicating that LL exposure affects ONL but does not produce RGC death. However, the photopigments melanopsin (OPN4) and neuropsin (OPN5) expressed in the inner retina were seen to modify their localization and expression during LL exposure. Our findings suggest that constant light during several days produces retinal remodeling and ONL cell death as well as significant changes in opsin expression in the inner nuclear layer.
Collapse
Affiliation(s)
- María M Benedetto
- Facultad de Ciencias Químicas, Departamento de Química Biológica "Dr. Ranwel Caputto", Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mario E Guido
- Facultad de Ciencias Químicas, Departamento de Química Biológica "Dr. Ranwel Caputto", Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María A Contin
- Facultad de Ciencias Químicas, Departamento de Química Biológica "Dr. Ranwel Caputto", Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| |
Collapse
|
9
|
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
|
10
|
Pupillary responses to short-wavelength light are preserved in aging. Sci Rep 2017; 7:43832. [PMID: 28266650 PMCID: PMC5339857 DOI: 10.1038/srep43832] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 01/30/2017] [Indexed: 01/22/2023] Open
Abstract
With aging, less blue light reaches the retina due to gradual yellowing of the lens. This could result in reduced activation of blue light-sensitive melanopsin-containing retinal ganglion cells, which mediate non-visual light responses (e.g., the pupillary light reflex, melatonin suppression, and circadian resetting). Herein, we tested the hypothesis that older individuals show greater impairment of pupillary responses to blue light relative to red light. Dose-response curves for pupillary constriction to 469-nm blue light and 631-nm red light were compared between young normal adults aged 21–30 years (n = 60) and older adults aged ≥50 years (normal, n = 54; mild cataract, n = 107; severe cataract, n = 18). Irrespective of wavelength, pupillary responses were reduced in older individuals and further attenuated by severe, but not mild, cataract. The reduction in pupillary responses was comparable in response to blue light and red light, suggesting that lens yellowing did not selectively reduce melanopsin-dependent light responses. Compensatory mechanisms likely occur in aging that ensure relative constancy of pupillary responses to blue light despite changes in lens transmission.
Collapse
|
11
|
Ouk K, Hughes S, Pothecary CA, Peirson SN, Morton AJ. Attenuated pupillary light responses and downregulation of opsin expression parallel decline in circadian disruption in two different mouse models of Huntington's disease. Hum Mol Genet 2016; 25:ddw359. [PMID: 28031289 PMCID: PMC5418835 DOI: 10.1093/hmg/ddw359] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/14/2016] [Accepted: 10/17/2016] [Indexed: 12/28/2022] Open
Abstract
Circadian deficits in Huntington's disease (HD) are recapitulated in both fragment (R6/2) and full-length (Q175) mouse models of HD. Circadian rhythms are regulated by the suprachiasmatic nuclei (SCN) in the hypothalamus, which are primarily entrained by light detected by the retina. The SCN receives input from intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the photopigment melanopsin, but also receive input from rods and cones. In turn, ipRGCs mediate a range of non-image forming responses to light including circadian entrainment and the pupillary light response (PLR). Retinal degeneration/dysfunction has been described previously in R6/2 mice. We investigated, therefore, whether or not circadian disruption in HD mice is due to abnormalities in retinal photoreception. We measured the expression of melanopsin, rhodopsin and cone opsin, as well as other retinal markers (tyrosine hydroxylase, calbindin, PKCα and Brna3), in R6/2 and Q175 mice at different stages of disease. We also measured the PLR as a 'readout' for ipRGC function and a marker of light reception by the retina. We found that the PLR was attenuated in both lines of HD mice. This was accompanied by a progressive downregulation of cone opsin and melanopsin expression. We suggest that disease-related changes in photoreception by the retina contribute to the progressive dysregulation of circadian rhythmicity and entrainment seen in HD mice. Colour vision is abnormal in HD patients. Therefore, if retinal deficits similar to those seen in HD mice are confirmed in patients, specifically designed light therapy may be an effective strategy to improve circadian dysfunction.
Collapse
Affiliation(s)
- Koliane Ouk
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Steven Hughes
- Nuffield Department of Clinical Neurosciences, Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK
| | - Carina A Pothecary
- Nuffield Department of Clinical Neurosciences, Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK
| | - Stuart N Peirson
- Nuffield Department of Clinical Neurosciences, Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK
| | - A Jennifer Morton
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| |
Collapse
|
12
|
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
|
13
|
Najjar RP, Chiquet C, Teikari P, Cornut PL, Claustrat B, Denis P, Cooper HM, Gronfier C. Aging of non-visual spectral sensitivity to light in humans: compensatory mechanisms? PLoS One 2014; 9:e85837. [PMID: 24465738 PMCID: PMC3900444 DOI: 10.1371/journal.pone.0085837] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/02/2013] [Indexed: 11/30/2022] Open
Abstract
The deterioration of sleep in the older population is a prevalent feature that contributes to a decrease in quality of life. Inappropriate entrainment of the circadian clock by light is considered to contribute to the alteration of sleep structure and circadian rhythms in the elderly. The present study investigates the effects of aging on non-visual spectral sensitivity to light and tests the hypothesis that circadian disturbances are related to a decreased light transmittance. In a within-subject design, eight aged and five young subjects were exposed at night to 60 minute monochromatic light stimulations at 9 different wavelengths (420-620 nm). Individual sensitivity spectra were derived from measures of melatonin suppression. Lens density was assessed using a validated psychophysical technique. Although lens transmittance was decreased for short wavelength light in the older participants, melatonin suppression was not reduced. Peak of non-visual sensitivity was, however, shifted to longer wavelengths in the aged participants (494 nm) compared to young (484 nm). Our results indicate that increased lens filtering does not necessarily lead to a decreased non-visual sensitivity to light. The lack of age-related decrease in non-visual sensitivity to light may involve as yet undefined adaptive mechanisms.
Collapse
Affiliation(s)
- Raymond P. Najjar
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| | - Christophe Chiquet
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University Joseph Fourier Grenoble 1, Grenoble, France
- Department of Ophthalmology, CHU Grenoble, Grenoble, France
| | - Petteri Teikari
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| | - Pierre-Loïc Cornut
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- Department of Ophthalmology, CHU de Lyon Hôpital Edouard Herriot, Lyon, France
| | - Bruno Claustrat
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- Center of Biology, Hormone Laboratory, Bron, France
| | - Philippe Denis
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- Department of Ophtalmology, Hôpital de la Croix-Rousse, Lyon, France
| | - Howard M. Cooper
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| | - Claude Gronfier
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| |
Collapse
|
14
|
Ramsey DJ, Ramsey KM, Vavvas DG. Genetic advances in ophthalmology: the role of melanopsin-expressing, intrinsically photosensitive retinal ganglion cells in the circadian organization of the visual system. Semin Ophthalmol 2013; 28:406-21. [PMID: 24010846 DOI: 10.3109/08820538.2013.825294] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Daily changes in the light-dark cycle are the principal environmental signal that enables organisms to synchronize their internal biology with the 24-hour day-night cycle. In humans, the visual system is integral to photoentrainment and is primarily driven by a specialized class of intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the photopigment melanopsin (OPN4) in the inner retina. These cells project through the retinohypothalamic tract (RHT) to the suprachiasmatic nuclei (SCN) of the hypothalamus, which serves as the body's master biological clock. At the same time, the retina itself possesses intrinsic circadian oscillations, exemplified by diurnal fluctuations in visual sensitivity, neurotransmitter levels, and outer segment turnover rates. Recently, it has been noted that both central and peripheral oscillators share a molecular clock consisting of an endogenous, circadian-driven, transcription-translation feedback loop that cycles with a periodicity of approximately 24 hours. This review will cover the role that melanopsin and ipRGCs play in the circadian organization of the visual system.
Collapse
Affiliation(s)
- David J Ramsey
- Retina Service, Harvard Medical School, Massachusetts Eye and Ear Infirmary and Mass General Hospital , Boston, Massachusetts , USA
| | | | | |
Collapse
|
15
|
Goetze JP, Eiland S, Svendsen LB, Vainer B, Hannibal J, Rehfeld JF. Characterization of gastrins and their receptor in solid human gastric adenocarcinomas. Scand J Gastroenterol 2013; 48:688-95. [PMID: 23544442 DOI: 10.3109/00365521.2013.783101] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE The gastrin and the gastrin/CCK-B receptor genes are co-expressed in several carcinomas. The primary translational product, progastrin, however, is processed to several peptides of which only those that are α-amidated at their C-terminus are receptor ligands. So far, characterization of the progastrin-derived peptides in gastric cancer has not been reported. The authors therefore examined the molecular nature of gastrin and its receptor in human gastric carcinomas. MATERIALS AND METHODS Twenty patients with adenocarcinoma underwent partial or total gastrectomy. In samples from each carcinoma, gastrin peptides were characterized, using a library of sequence-specific immunoassays. Expression was also demonstrated by immunohistochemistry. In addition, the gastrin and gastrin/CCK-B receptor gene expression was quantitated using real-time PCR, and the receptor protein demonstrated by western blotting. RESULTS α-Amidated gastrins were detectable in 16 of 20 carcinomas (median concentration 2.1 pmol/g tissue; range 0-386 pmol/g tissue). The tissue concentrations correlated closely to the gastrin mRNA contents (r = 0.75, p < 0.0001). Moreover, progastrin and non-amidated processing intermediates, including glycine-extended gastrins, were detected in 19 carcinomas. Immunohistochemistry corroborated gastrin expression in carcinoma cells. Chromatography revealed extensive progastrin processing with α-amidated gastrin-34 and -17 (tyrosyl-sulfated as well as non-sulfated) as major products. Finally, gastrin/CCK-B receptor mRNA and protein were detected in all tumors. CONCLUSIONS The results show that the elements for a local loop of α-amidated gastrins and their receptor are detectable in 80% of human gastric adenocarcinomas. Therefore, the results support the contention that locally expressed gastrin may be involved in the tumorigenesis of gastric adenocarcinomas.
Collapse
Affiliation(s)
- Jens Peter Goetze
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
| | | | | | | | | | | |
Collapse
|
16
|
Hong J, Zeng Q, Wang H, Kuo DS, Baldridge WH, Wang N. Controlling the number of melanopsin-containing retinal ganglion cells by early light exposure. Exp Eye Res 2013; 111:17-26. [DOI: 10.1016/j.exer.2013.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 03/08/2013] [Accepted: 03/14/2013] [Indexed: 11/28/2022]
|
17
|
Hannibal J, Georg B, Fahrenkrug J. Differential expression of melanopsin mRNA and protein in Brown Norwegian rats. Exp Eye Res 2013. [DOI: 10.1016/j.exer.2012.11.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
18
|
González-Menéndez I, Contreras F, García-Fernández JM, Cernuda-Cernuda R. Perinatal development of melanopsin expression in the mouse retina. Brain Res 2011; 1419:12-8. [DOI: 10.1016/j.brainres.2011.08.061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 08/17/2011] [Accepted: 08/24/2011] [Indexed: 01/21/2023]
|
19
|
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) respond to light in the absence of all rod and cone photoreceptor input. The existence of these ganglion cell photoreceptors, although predicted from observations scattered over many decades, was not established until it was shown that a novel photopigment, melanopsin, was expressed in retinal ganglion cells of rodents and primates. Phototransduction in mammalian ipRGCs more closely resembles that of invertebrate than vertebrate photoreceptors and appears to be mediated by transient receptor potential channels. In the retina, ipRGCs provide excitatory drive to dopaminergic amacrine cells and ipRGCs are coupled to GABAergic amacrine cells via gap junctions. Several subtypes of ipRGC have been identified in rodents based on their morphology, physiology and expression of molecular markers. ipRGCs convey irradiance information centrally via the optic nerve to influence several functions including photoentrainment of the biological clock located in the hypothalamus, the pupillary light reflex, sleep and perhaps some aspects of vision. In addition, ipRGCs may also contribute irradiance signals that interface directly with the autonomic nervous system to regulate rhythmic gene activity in major organs of the body. Here we review the early work that provided the motivation for searching for a new mammalian photoreceptor, the ground-breaking discoveries, current progress that continues to reveal the unusual properties of these neuron photoreceptors, and directions for future investigation.
Collapse
Affiliation(s)
- Gary E Pickard
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE 68583, USA.
| | | |
Collapse
|
20
|
González-Menéndez I, Contreras F, Cernuda-Cernuda R, Provencio I, García-Fernández JM. Postnatal development and functional adaptations of the melanopsin photoreceptive system in the albino mouse retina. Invest Ophthalmol Vis Sci 2010; 51:4840-7. [PMID: 20435589 DOI: 10.1167/iovs.10-5253] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To study the melanopsin system of the albino CD1 mouse retina during postnatal development. METHODS Pups were kept under different ambient conditions: light/dark (LD) cycles, constant light (LL), constant darkness (DD), LL followed by LD, and DD followed by LL. Using immunohistochemistry, melanopsin-expressing cells were classified as M1 or M2 according to the location of their somata and dendritic processes and were counted. RESULTS Under LD cycles an increase in the number of immunoreactive cells was observed within the first week of postnatal development. When mice were maintained in DD, the increase in the number of immunopositive cells detected was significantly higher than that in LD. On the contrary, when mice were exposed to LL within the same period, no increase was detected. To determine whether the effect of LL during the early postnatal period was reversible, the authors studied animals born in LL and subsequently maintained under LD cycles. After 3 days in LD, these animals showed a significant increase in melanopsin cell number. However, after 1 month in LD, the number was similar to that of the LD controls. Surprisingly, when mice born in DD were exposed to LL, no decrease was detected, though the immunostaining was of low intensity. CONCLUSIONS The amount of melanopsin protein per cell varies, depending on ambient light conditions. Periods of darkness or, more likely, the sequence of light and dark periods occurring under the daily cycles might be necessary for the normal development of the melanopsin system.
Collapse
|
21
|
Intrinsically photosensitive retinal ganglion cells. SCIENCE CHINA-LIFE SCIENCES 2010; 53:58-67. [PMID: 20596956 DOI: 10.1007/s11427-010-0024-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2009] [Accepted: 12/30/2009] [Indexed: 01/13/2023]
Abstract
A new mammalian photoreceptor was recently discovered to reside in the ganglion cell layer of the inner retina. These intrinsically photosensitive retinal ganglion cells (ipRGCs) express a photopigment, melanopsin that confers upon them the ability to respond to light in the absence of all rod and cone photoreceptor input. Although relatively few in number, ipRGCs extend their dendrites across large expanses of the retina making them ideally suited to function as irradiance detectors to assess changes in ambient light levels. Phototransduction in ipRGCs appears to be mediated by transient receptor potential channels more closely resembling the phototransduction cascade of invertebrate than vertebrate photoreceptors. ipRGCs convey irradiance information centrally via the optic nerve to influence several functions. ipRGCs are the primary retinal input to the hypothalamic suprachiasmatic nucleus (SCN), a circadian oscillator and biological clock, and this input entrains the SCN to the day/night cycle. ipRGCs contribute irradiance signals that regulate pupil size and they also provide signals that interface with the autonomic nervous system to regulate rhythmic gene activity in major organs of the body. ipRGCs also provide excitatory drive to dopaminergic amacrine cells in the retina, providing a novel basis for the restructuring of retinal circuits by light. Here we review the ground-breaking discoveries, current progress and directions for future investigation.
Collapse
|
22
|
Moldrup ML, Georg B, Falktoft B, Mortensen R, Hansen JL, Fahrenkrug J. Light inducesFosexpression via extracellular signal-regulated kinases 1/2 in melanopsin-expressing PC12 cells. J Neurochem 2010; 112:797-806. [DOI: 10.1111/j.1471-4159.2009.06504.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
23
|
Ingham ES, Günhan E, Fuller PM, Fuller CA. Immunotoxin-induced ablation of melanopsin retinal ganglion cells in a non-murine mammalian model. J Comp Neurol 2009; 516:125-40. [PMID: 19575450 DOI: 10.1002/cne.22103] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In mammals, non-image-forming visual functions, including circadian photoentrainment and the pupillary light reflex, are thought to be mediated by the combination of rods, cones, and the melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs). Although several genetic models have been developed to clarify the individual roles of the rod, cone, and ipRGC systems in mediating non-image visual function, assessing the in vivo role(s) of the ipRGCs has been complicated by the possibility of ontogenetic issues in these genetically modified animal models. In the present study, we describe the development and validation of an immunotoxin that specifically targets the ipRGC population in the mature mammalian retina. This ipRGC immunotoxin, consisting of saporin conjugated to a melanopsin polyclonal antibody, was evaluated with respect to its effectiveness and specificity in depleting the ipRGC population in the fully developed rat retina. The results showed that the ipRGC toxin rapidly and permanently depleted approximately 70% of the ipRGC population, without inducing appreciable changes in the cell number or morphology of any of the non-melanopsin-containing retinal cell populations investigated. These findings suggest that the newly developed ipRGC immunotoxin provides a potent method for achieving relatively rapid, permanent, and selective depletion of the ipRGC population in a non-murine model system. The development of this ipRGC-ablation method is the next step in elucidating the role of ipRGCs in mediating non-visual and circadian light-resetting responses in a wide range of non-murine mammalian models.
Collapse
Affiliation(s)
- Elizabeth S Ingham
- Department of Neurobiology, Physiology & Behavior, University of California, Davis, California 95616, USA
| | | | | | | |
Collapse
|
24
|
Fahrenkrug J, Falktoft B, Georg B, Rask L. N-linked deglycosylated melanopsin retains its responsiveness to light. Biochemistry 2009; 48:5142-8. [PMID: 19413349 DOI: 10.1021/bi900249n] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanopsin is an opsin expressed in the plasma membrane of retinal ganglion cells that mainly project to the circadian clock and thus is important for nonvisual responses to light. Rat melanopsin contains two potential sites (Asn31 and Asn35) for N-linked glycosylation in the N-terminal extracellular part. To investigate if melanopsin is N-linked glycosylated and whether N-bound glycans influence the response of melanopsin to light as evidenced by Fos mRNA induction, we transfected PC12 cells to stably express rat wild-type melanopsin or mutant melanopsin lacking both N-linked glycosylation sites. Immunoblotting for membrane-bound melanopsin from the PC12 cells transfected to express wild-type melanopsin disclosed two immunoreactive bands of 62 and 49 kDa. Removal of N-linked glycosylation by tunicamycin or PNGase F changed the 62 kDa band to a 55 kDa band, while the 49 kDa band corresponding to the core melanopsin protein was unaffected. Likewise, mutation of the two extracellular N-linked glycosylation sites gave a melanopsin size comparable to that of PNGase F or tunicamycin treatment (55 kDa). Further in vitro O-linked deglycosylation of wild-type or mutant melanopsin with O-glycosidase and neuraminidase converted the 55 kDa band to a 49 kDa band. Finally, neither in vivo N-linked deglycosylation nor mutations of the two N-linked glycosylation sites significantly affected melanopsin function measured by Fos induction after light stimulation. In conclusion, we have shown that heterologously expressed rat melanopsin is both N-linked and O-linked glycosylated and that N-linked glycosylation is not crucial for the melanopsin response to light.
Collapse
Affiliation(s)
- Jan Fahrenkrug
- Department of Clinical Biochemistry, Bispebjerg Hospital, Faculty of Health Sciences, University of Copenhagen, DK-2400 Copenhagen NV, Denmark.
| | | | | | | |
Collapse
|
25
|
González-Menéndez I, Contreras F, Cernuda-Cernuda R, García-Fernández JM. Daily rhythm of melanopsin-expressing cells in the mouse retina. Front Cell Neurosci 2009; 3:3. [PMID: 19562086 PMCID: PMC2701677 DOI: 10.3389/neuro.03.003.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 06/05/2009] [Indexed: 11/13/2022] Open
Abstract
In addition to some other functions, melanopsin-expressing retinal ganglion cells (RGCs) constitute the principal mediators of the circadian photoentrainment, a process by which the suprachiasmatic nucleus (the central clock of mammals), adjusts daily to the external day/night cycle. In the present study these RGCs were immunohistochemically labelled using a specific polyclonal antiserum raised against mouse melanopsin. A daily oscillation in the number of immunostained cells was detected in mice kept under a light / dark (LD) cycle. One hour before the lights were on (i.e., the end of the night period) the highest number of immunopositive cells was detected while the lowest was seen 4 h later (i.e., within the first hours of the light period). This finding suggests that some of the melanopsin-expressing RGCs “turn on” and “off” during the day/night cycle. We have also detected that these daily variations already occur in the early postnatal development, when the rod/cone photoreceptor system is not yet functional. Two main melanopsin-expressing cell subpopulations could be found within the retina: M1 cells showed robust dendritic arborization within the OFF sublamina of the inner plexiform layer (IPL), whilst M2 cells had fine dendritic processes within the ON sublamina of the IPL. These two cell subpopulations also showed different daily oscillations throughout the LD cycle. In order to find out whether or not the melanopsin rhythm was endogenous, other mice were maintained in constant darkness for 6 days. Under these conditions, no defined rhythm was detected, which suggests that the daily oscillation detected either is light-dependent or is gradually lost under constant conditions. This is the first study to analyze immunohistochemically the daily oscillation of the number of melanopsin-expressing cells in the mouse retina.
Collapse
|
26
|
Falktoft B, Georg B, Fahrenkrug J. Calmodulin interacts with PAC1 and VPAC2 receptors and regulates PACAP-induced FOS expression in human neuroblastoma cells. Neuropeptides 2009; 43:53-61. [PMID: 19269029 DOI: 10.1016/j.npep.2009.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 02/05/2009] [Accepted: 02/05/2009] [Indexed: 10/21/2022]
Abstract
The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) mediates its physiological functions through activation of PAC1, VPAC1 and VPAC2 receptors, and the ubiquitous Ca(2+)-sensor calmodulin has been implicated in PACAP-induced signaling. The immediate early response gene FOS is a well-known marker of neuronal activation, so we used a human neuroblastoma cell line NB-1 to explore the role of calmodulin in PACAP-induced FOS gene expression. We observed both short-term and prolonged altered PACAP-mediated activation of the FOS gene in the presence of the calmodulin-antagonist W-7. NB-1 cells were shown to express PAC1 and VPAC2 receptors, and immunoprecipitation of both receptors displayed a co-association with calmodulin in the absence of Ca(2+). Our findings indicate a novel mechanism of calmodulin in regulating PACAP signaling by possible interaction with the inactive state of PAC1 and VPAC2 receptors.
Collapse
Affiliation(s)
- Birgitte Falktoft
- Department of Clinical Biochemistry, Bispebjerg Hospital, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
| | | | | |
Collapse
|
27
|
Abstract
Recent publications in the Journal of Biological Rhythms have focused on the hypothesis that the property of melanopsin bistability is functionally translated to in vivo mammalian physiology. Physiological consequences of photopigment bistability likely can be inferred from the more extensive invertebrate literature. In invertebrates, photopigment bistability results in (a) photoreceptor independence from specialized chromophore regenerating systems, (b) long-wavelength enhancement of a blue light effect, (c) expression of a prolonged depolarization after potential following intense blue light stimulation,and (d) photopigment endocytosis following chronic short-wavelength light exposure. If analogous physiological phenomena result from melanopsin bistability in mammals, then one can take advantage of the spectral composition of a light source to modulate its impact on photoentrainment and other light-dependent circadian phenomena. In any event,investigators studying phenomena that are affected by photic stimulation of intrinsically photosensitive retinal ganglion cells should detail the spectral composition of their light sources before, during, and after an experimental photic stimulus.
Collapse
Affiliation(s)
- Mark D Rollag
- Department of Biology, University of Virginia, Charlottesville, VA, USA.
| |
Collapse
|
28
|
Jusuf PR, Lee SCS, Hannibal J, Grünert U. Characterization and synaptic connectivity of melanopsin-containing ganglion cells in the primate retina. Eur J Neurosci 2008; 26:2906-21. [PMID: 18001286 DOI: 10.1111/j.1460-9568.2007.05924.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanopsin is a photopigment expressed in retinal ganglion cells, which are intrinsically photosensitive and are also involved in retinal circuits arising from rod and cone photoreceptors. This circuitry, however, is poorly understood. Here, we studied the morphology, distribution and synaptic input to melanopsin-containing ganglion cells in a New World monkey, the common marmoset (Callithrix jacchus). The dendrites of melanopsin-containing cells in marmoset stratify either close to the inner nuclear layer (outer stratifying), or close to the ganglion cell layer (inner stratifying). The dendritic fields of outer-stratifying cells tile the retina, with little overlap. However, the dendritic fields of outer-stratifying cells largely overlap with the dendritic fields of inner-stratifying cells. Thus, inner-stratifying and outer-stratifying cells may form functionally independent populations. The synaptic input to melanopsin-containing cells was determined using synaptic markers (antibodies to C-terminal binding protein 2, CtBP2, for presumed bipolar synapses, and antibodies to gephyrin for presumed amacrine synapses). Both outer-stratifying and inner-stratifying cells show colocalized immunoreactive puncta across their entire dendritic tree for both markers. The density of CtBP2 puncta on inner dendrites was about 50% higher than that on outer dendrites. The density of gephyrin puncta was comparable for outer and inner dendrites but higher than the density of CtBP2 puncta. The inner-stratifying cells may receive their input from a type of diffuse bipolar cell (DB6). Our results are consistent with the idea that both outer and inner melanopsin cells receive bipolar and amacrine input across their dendritic tree.
Collapse
Affiliation(s)
- Patricia R Jusuf
- National Vision Research Institute of Australia, Cnr Keppel & Cardigan Streets, Carlton, Victoria 3053, Australia
| | | | | | | |
Collapse
|