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Narayan DS, Wood JPM, Chidlow G, Casson RJ. A review of the mechanisms of cone degeneration in retinitis pigmentosa. Acta Ophthalmol 2016; 94:748-754. [PMID: 27350263 DOI: 10.1111/aos.13141] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/30/2016] [Indexed: 12/12/2022]
Abstract
Retinitis pigmentosa (RP) is an inherited condition that features degeneration of rod and cone photoreceptors. In all forms of RP, the genetic mutation is expressed exclusively in rods; however, cones die too. The secondary death of cones in RP remains somewhat mysterious. A better understanding of the mechanisms that cause cone degeneration in RP could lead to novel treatments that preserve cones. There are a number of prevailing theories that attempt to explain cone degeneration in RP. One concept is that cone survival is dependent on trophic factors produced by rods. Another hypothesis is that cones suffer from a nutrient shortage after rods have been lost. Additionally, oxidative stress and pro-inflammatory microglial activation have also been suggested to play a role in cone death. The present review evaluates the evidence supporting these theories and provides an update on the mechanisms of cone degeneration in RP.
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Affiliation(s)
- Daniel S. Narayan
- Ophthalmic Research Laboratories; Hanson Institute Centre for Neurological Diseases; Adelaide South Australia Australia
- South Australian Institute of Ophthalmology; University of Adelaide; Adelaide South Australia Australia
| | - John P. M. Wood
- Ophthalmic Research Laboratories; Hanson Institute Centre for Neurological Diseases; Adelaide South Australia Australia
- South Australian Institute of Ophthalmology; University of Adelaide; Adelaide South Australia Australia
| | - Glyn Chidlow
- Ophthalmic Research Laboratories; Hanson Institute Centre for Neurological Diseases; Adelaide South Australia Australia
- South Australian Institute of Ophthalmology; University of Adelaide; Adelaide South Australia Australia
| | - Robert J. Casson
- Ophthalmic Research Laboratories; Hanson Institute Centre for Neurological Diseases; Adelaide South Australia Australia
- South Australian Institute of Ophthalmology; University of Adelaide; Adelaide South Australia Australia
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Keenan WT, Rupp AC, Ross RA, Somasundaram P, Hiriyanna S, Wu Z, Badea TC, Robinson PR, Lowell BB, Hattar SS. A visual circuit uses complementary mechanisms to support transient and sustained pupil constriction. eLife 2016; 5:e15392. [PMID: 27669145 PMCID: PMC5079752 DOI: 10.7554/elife.15392] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 09/22/2016] [Indexed: 12/22/2022] Open
Abstract
Rapid and stable control of pupil size in response to light is critical for vision, but the neural coding mechanisms remain unclear. Here, we investigated the neural basis of pupil control by monitoring pupil size across time while manipulating each photoreceptor input or neurotransmitter output of intrinsically photosensitive retinal ganglion cells (ipRGCs), a critical relay in the control of pupil size. We show that transient and sustained pupil responses are mediated by distinct photoreceptors and neurotransmitters. Transient responses utilize input from rod photoreceptors and output by the classical neurotransmitter glutamate, but adapt within minutes. In contrast, sustained responses are dominated by non-conventional signaling mechanisms: melanopsin phototransduction in ipRGCs and output by the neuropeptide PACAP, which provide stable pupil maintenance across the day. These results highlight a temporal switch in the coding mechanisms of a neural circuit to support proper behavioral dynamics.
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Affiliation(s)
| | - Alan C Rupp
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Rachel A Ross
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Department of Psychiatry, Massachusetts General Hospital, Boston, United States
| | - Preethi Somasundaram
- Department of Biological Sciences, University of Marlyand, Baltimore, United States
| | - Suja Hiriyanna
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Zhijian Wu
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Tudor C Badea
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Phyllis R Robinson
- Department of Biological Sciences, University of Marlyand, Baltimore, United States
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Program in Neuroscience, Harvard Medical School, Boston, United States
| | - Samer S Hattar
- Department of Biology, Johns Hopkins University, Baltimore, United States
- Department of Neuroscience, Johns Hopkins University, Baltimore, United States
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Dasilva M, Storchi R, Davis KE, Grieve KL, Lucas RJ. Melanopsin supports irradiance-driven changes in maintained activity in the superior colliculus of the mouse. Eur J Neurosci 2016; 44:2314-23. [DOI: 10.1111/ejn.13336] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/23/2016] [Accepted: 07/12/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Miguel Dasilva
- Faculty of Life Sciences; University of Manchester; Manchester M13 9PT UK
| | - Riccardo Storchi
- Faculty of Life Sciences; University of Manchester; Manchester M13 9PT UK
| | - Katherine E. Davis
- Faculty of Life Sciences; University of Manchester; Manchester M13 9PT UK
| | - Kenneth L. Grieve
- Faculty of Life Sciences; University of Manchester; Manchester M13 9PT UK
| | - Robert J. Lucas
- Faculty of Life Sciences; University of Manchester; Manchester M13 9PT UK
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Marangoni D, Vijayasarathy C, Bush RA, Wei LL, Wen R, Sieving PA. Intravitreal Ciliary Neurotrophic Factor Transiently Improves Cone-Mediated Function in a CNGB3-/- Mouse Model of Achromatopsia. Invest Ophthalmol Vis Sci 2016; 56:6810-22. [PMID: 26567794 DOI: 10.1167/iovs.15-16866] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Ciliary neurotrophic factor (CNTF) was recently shown to augment cone function in CNGB3 mutant achromat dogs. However, testing CNTF-releasing implant in human CNGB3 achromats failed to show benefit. We evaluated the effects of CNTF protein on the retinal function in an additional achromatopsia model, the CNGB3-/- mouse. METHODS Fifty-nine CNGB3-/- mice (postnatal day [PD] ± SD = 30 ± 7) received a unilateral intravitreal injection of 1 or 2 μg CNTF protein, and 15 wild-type (WT) mice (PD = 34 ± 3) received 1 μg CNTF. Retinal function was evaluated by flash ERG and photopic flicker ERG (fERG) at 7 and 14 days after treatment. RESULTS Seven days post CNTF, the photopic b-wave Vmax was significantly increased in CNGB3-/- mice (P < 0.01), whereas it was reduced in WT mice (P < 0.05). Ciliary neurotrophic factor significantly increased the amplitude of photopic fERG and the photopic oscillatory potentials (OPs) in CNGB3-/- mice. Ciliary neurotrophic factor did not alter the scotopic a-wave in either CNGB3-/- or WT mice, but it increased the scotopic b-wave k (P < 0.01) in CNGB3-/- mice, indicating diminished scotopic sensitivity, and reduced the scotopic b-wave Vmax in WT mice (P < 0.05). No difference was found in ERG parameters between 1 or 2 μg CNTF. Fourteen days after CNTF injection the ERG changes in CNGB3-/- mice were lost. CONCLUSIONS Intravitreal bolus CNTF protein caused a small and transient improvement of cone-mediated function in CNGB3-/- mice, whereas it reduced rod-mediated function. The increase in photopic OPs and the lack of changes in scotopic a-wave suggest a CNTF effect on the inner retina.
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Affiliation(s)
- Dario Marangoni
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States 3Department of Biotechnology and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy
| | - Camasamudram Vijayasarathy
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Ronald A Bush
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Lisa L Wei
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Rong Wen
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami, Miller School of Medicine, Miami, Florida, United States
| | - Paul A Sieving
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States 2National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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HCN1 Channels Enhance Rod System Responsivity in the Retina under Conditions of Light Exposure. PLoS One 2016; 11:e0147728. [PMID: 26807953 PMCID: PMC4725747 DOI: 10.1371/journal.pone.0147728] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/07/2016] [Indexed: 11/20/2022] Open
Abstract
Purpose Vision originates in rods and cones at the outer retina. Already at these early stages, diverse processing schemes shape and enhance image information to permit perception over a wide range of lighting conditions. In this work, we address the role of hyperpolarization-activated and cyclic nucleotide-gated channels 1 (HCN1) in rod photoreceptors for the enhancement of rod system responsivity under conditions of light exposure. Methods To isolate HCN1 channel actions in rod system responses, we generated double mutant mice by crossbreeding Hcn1-/- mice with Cnga3-/- mice in which cones are non-functional. Retinal function in the resulting Hcn1-/-Cnga3-/- animals was followed by means of electroretinography (ERG) up to the age of four month. Retinal imaging via scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) was also performed to exclude potential morphological alterations. Results This study on Hcn1-/-Cnga3-/- mutant mice complements our previous work on HCN1 channel function in the retina. We show here in a functional rod-only setting that rod responses following bright light exposure terminate without the counteraction of HCN channels much later than normal. The resulting sustained signal elevation does saturate the retinal network due to an intensity-dependent reduction in the dynamic range. In addition, the lack of rapid adaptational feedback modulation of rod photoreceptor output via HCN1 in this double mutant limits the ability to follow repetitive (flicker) stimuli, particularly under mesopic conditions. Conclusions This work corroborates the hypothesis that, in the absence of HCN1-mediated feedback, the amplitude of rod signals remains at high levels for a prolonged period of time, leading to saturation of the retinal pathways. Our results demonstrate the importance of HCN1 channels for regular vision.
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Schön C, Asteriti S, Koch S, Sothilingam V, Garrido MG, Tanimoto N, Herms J, Seeliger MW, Cangiano L, Biel M, Michalakis S. Loss of HCN1 enhances disease progression in mouse models of CNG channel-linked retinitis pigmentosa and achromatopsia. Hum Mol Genet 2016; 25:1165-75. [DOI: 10.1093/hmg/ddv639] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 12/22/2015] [Indexed: 01/24/2023] Open
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Understanding Cone Photoreceptor Cell Death in Achromatopsia. RETINAL DEGENERATIVE DISEASES 2016; 854:231-6. [DOI: 10.1007/978-3-319-17121-0_31] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Giblin JP, Comes N, Strauss O, Gasull X. Ion Channels in the Eye: Involvement in Ocular Pathologies. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 104:157-231. [PMID: 27038375 DOI: 10.1016/bs.apcsb.2015.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The eye is the sensory organ of vision. There, the retina transforms photons into electrical signals that are sent to higher brain areas to produce visual sensations. In the light path to the retina, different types of cells and tissues are involved in maintaining the transparency of avascular structures like the cornea or lens, while others, like the retinal pigment epithelium, have a critical role in the maintenance of photoreceptor function by regenerating the visual pigment. Here, we have reviewed the roles of different ion channels expressed in ocular tissues (cornea, conjunctiva and neurons innervating the ocular surface, lens, retina, retinal pigment epithelium, and the inflow and outflow systems of the aqueous humor) that are involved in ocular disease pathophysiologies and those whose deletion or pharmacological modulation leads to specific diseases of the eye. These include pathologies such as retinitis pigmentosa, macular degeneration, achromatopsia, glaucoma, cataracts, dry eye, or keratoconjunctivitis among others. Several disease-associated ion channels are potential targets for pharmacological intervention or other therapeutic approaches, thus highlighting the importance of these channels in ocular physiology and pathophysiology.
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Affiliation(s)
- Jonathan P Giblin
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Nuria Comes
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Xavier Gasull
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
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Díaz NM, Morera LP, Guido ME. Melanopsin and the Non-visual Photochemistry in the Inner Retina of Vertebrates. Photochem Photobiol 2015; 92:29-44. [DOI: 10.1111/php.12545] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/09/2015] [Indexed: 01/28/2023]
Affiliation(s)
- Nicolás M. Díaz
- Departamento de Química Biológica-CIQUIBIC (CONICET); Facultad de Ciencias Químicas; Universidad Nacional de Córdoba (UNC); Córdoba Argentina
| | - Luis P. Morera
- Departamento de Química Biológica-CIQUIBIC (CONICET); Facultad de Ciencias Químicas; Universidad Nacional de Córdoba (UNC); Córdoba Argentina
| | - Mario E. Guido
- Departamento de Química Biológica-CIQUIBIC (CONICET); Facultad de Ciencias Químicas; Universidad Nacional de Córdoba (UNC); Córdoba Argentina
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Li FF, Huang XF, Chen J, Yu XD, Zheng MQ, Lu F, Jin ZB, Gan DK. Identification of novel mutations by targeted exome sequencing and the genotype-phenotype assessment of patients with achromatopsia. J Transl Med 2015; 13:334. [PMID: 26493561 PMCID: PMC4618873 DOI: 10.1186/s12967-015-0694-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/10/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Achromatopsia (ACHM) is a severe congenital autosomal recessive retinal disorder caused by loss of cone photoreceptors. Here, we aimed to determine the underlying genetic lesions and phenotypic correlations in two Chinese families with ACHM. METHODS Medical history and clinical evaluation were obtained from both families. Targeted exome sequencing (TES) was performed on 201 disease-causing genes of inherited retinal dystrophies to screen for ACHM causative mutations in the two probands. RESULTS The compound heterozygous mutations in CNGA3 (c.1074G > A, p.W358X; c.1706G > A, p.R569H) were identified in the first proband, and a novel homozygous mutation (c.968C > A, p.A323D) was detected in the other pedigree. The proposed topological model of the CNGA3 polypeptide suggested that the missense mutations primarily affected the transmembrane helix 5 and the cGMP-binding domain, respectively. Crystal structure modeling of the cyclic nucleotide-gated cation channel α-3 (CNGA3) protein encoded by the CNGA3 gene revealed an abnormal combined structure generated by R569H. CONCLUSIONS We firstly used the TES approach to identify genetic alterations in patients with ACHM. We uncovered three mutations in CNGA3, including one novel mutation. Our results not only expand the genotypic spectrum for CNGA3 mutations, but also demonstrate that the TES approach is a valuable tool for molecular diagnosis.
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Affiliation(s)
- Fen-Fen Li
- The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, Wenzhou, 325027, China.
| | - Xiu-Feng Huang
- The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, Wenzhou, 325027, China.
| | - Jie Chen
- The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, Wenzhou, 325027, China.
| | - Xu-Dong Yu
- The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, Wenzhou, 325027, China.
| | - Mei-Qin Zheng
- The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, Wenzhou, 325027, China.
| | - Fan Lu
- The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, Wenzhou, 325027, China.
| | - Zi-Bing Jin
- The Eye Hospital of Wenzhou Medical University, The State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health, Wenzhou, 325027, China.
| | - De-Kang Gan
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fen Yang Road, Shanghai, 200031, People's Republic of China.
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Veleri S, Lazar CH, Chang B, Sieving PA, Banin E, Swaroop A. Biology and therapy of inherited retinal degenerative disease: insights from mouse models. Dis Model Mech 2015; 8:109-29. [PMID: 25650393 PMCID: PMC4314777 DOI: 10.1242/dmm.017913] [Citation(s) in RCA: 179] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Retinal neurodegeneration associated with the dysfunction or death of photoreceptors is a major cause of incurable vision loss. Tremendous progress has been made over the last two decades in discovering genes and genetic defects that lead to retinal diseases. The primary focus has now shifted to uncovering disease mechanisms and designing treatment strategies, especially inspired by the successful application of gene therapy in some forms of congenital blindness in humans. Both spontaneous and laboratory-generated mouse mutants have been valuable for providing fundamental insights into normal retinal development and for deciphering disease pathology. Here, we provide a review of mouse models of human retinal degeneration, with a primary focus on diseases affecting photoreceptor function. We also describe models associated with retinal pigment epithelium dysfunction or synaptic abnormalities. Furthermore, we highlight the crucial role of mouse models in elucidating retinal and photoreceptor biology in health and disease, and in the assessment of novel therapeutic modalities, including gene- and stem-cell-based therapies, for retinal degenerative diseases.
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Affiliation(s)
- Shobi Veleri
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Csilla H Lazar
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA. Molecular Biology Center, Interdisciplinary Research Institute on Bio-Nano Sciences, Babes-Bolyai-University, Cluj-Napoca, 400271, Romania
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Paul A Sieving
- National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Eyal Banin
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA. Center for Retinal and Macular Degenerations, Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Anand Swaroop
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Phytochemical analysis and effects of Pteris vittata extract on visual processes. J Nat Med 2015; 70:8-17. [DOI: 10.1007/s11418-015-0930-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 07/19/2015] [Indexed: 10/23/2022]
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Ma H, Butler MR, Thapa A, Belcher J, Yang F, Baehr W, Biel M, Michalakis S, Ding XQ. cGMP/Protein Kinase G Signaling Suppresses Inositol 1,4,5-Trisphosphate Receptor Phosphorylation and Promotes Endoplasmic Reticulum Stress in Photoreceptors of Cyclic Nucleotide-gated Channel-deficient Mice. J Biol Chem 2015; 290:20880-20892. [PMID: 26124274 DOI: 10.1074/jbc.m115.641159] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Indexed: 11/06/2022] Open
Abstract
Photoreceptor cyclic nucleotide-gated (CNG) channels play a pivotal role in phototransduction. Mutations in the cone CNG channel subunits CNGA3 and CNGB3 are associated with achromatopsia and cone dystrophies. We have shown endoplasmic reticulum (ER) stress-associated apoptotic cone death and increased phosphorylation of the ER Ca(2+) channel inositol 1,4,5-trisphosphate receptor 1 (IP3R1) in CNG channel-deficient mice. We also presented a remarkable elevation of cGMP and an increased activity of the cGMP-dependent protein kinase (protein kinase G, PKG) in CNG channel deficiency. This work investigated whether cGMP/PKG signaling regulates ER stress and IP3R1 phosphorylation in CNG channel-deficient cones. Treatment with PKG inhibitor and deletion of guanylate cyclase-1 (GC1), the enzyme producing cGMP in cones, were used to suppress cGMP/PKG signaling in cone-dominant Cnga3(-/-)/Nrl(-/-) mice. We found that treatment with PKG inhibitor or deletion of GC1 effectively reduced apoptotic cone death, increased expression levels of cone proteins, and decreased activation of Müller glial cells. Furthermore, we observed significantly increased phosphorylation of IP3R1 and reduced ER stress. Our findings demonstrate a role of cGMP/PKG signaling in ER stress and ER Ca(2+) channel regulation and provide insights into the mechanism of cone degeneration in CNG channel deficiency.
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Affiliation(s)
- Hongwei Ma
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Michael R Butler
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Arjun Thapa
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Josh Belcher
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Fan Yang
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Wolfgang Baehr
- John A. Moran Eye Center, University of Utah, Salt Lake City, Utah 84132
| | - Martin Biel
- Center for Integrated Protein Science Munich and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Xi-Qin Ding
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104.
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Tanimoto N, Sothilingam V, Kondo M, Biel M, Humphries P, Seeliger MW. Electroretinographic assessment of rod- and cone-mediated bipolar cell pathways using flicker stimuli in mice. Sci Rep 2015; 5:10731. [PMID: 26029863 PMCID: PMC5377071 DOI: 10.1038/srep10731] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/21/2015] [Indexed: 11/18/2022] Open
Abstract
Mouse full-field electroretinograms (ERGs) are dominated by responses of photoreceptors and depolarizing (ON-) bipolar cells, but not much of hyperpolarizing (OFF-) bipolar cells under conventional recording conditions. Here we investigate a novel ERG protocol in mice for functional assessment of the major ON- and OFF-bipolar cell pathways using flicker stimuli for a high luminance with varying frequency up to 30 Hz. Wild-type (WT) and functionally specific transgenic mice (Cnga3-/-, no cone photoreceptor function; rho-/-, no rod photoreceptor function; mGluR6-/-, no ON-bipolar cell function) were examined. The Cnga3-/- flicker ERG was similar to the WT flicker ERG at very low stimulus frequencies, whereas ERGs were comparable between WT and rho-/- mice at 5 Hz and above. Between 5 and 15 Hz, ERGs in mGluR6-/- mice differed in configuration and amplitude from those in WT and rho-/- mice; in contrast, response amplitudes above 15 Hz were comparable among WT, rho-/- and mGluR6-/- mice. In summary, we found three frequency ranges with these conditions that are dominated by activity in the rod pathways (below 5 Hz), cone ON-pathway (between 5 and 15 Hz), and cone OFF-pathway (above 15 Hz) that enables a quick overview of the functionality of the major bipolar cell pathways.
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Affiliation(s)
- Naoyuki Tanimoto
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University, Schleichstr. 4/3, D-72076 Tübingen, Germany
| | - Vithiyanjali Sothilingam
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University, Schleichstr. 4/3, D-72076 Tübingen, Germany
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, 2-175 Edobashi, Tsu, Mie 514-8507, Japan
| | - Martin Biel
- Center for Integrated Protein Science Munich, CIPSM and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, D-81377 München, Germany
| | - Peter Humphries
- The Ocular Genetics Unit, Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Mathias W Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University, Schleichstr. 4/3, D-72076 Tübingen, Germany
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Thierry M, Pasquis B, Buteau B, Fourgeux C, Dembele D, Leclere L, Gambert-Nicot S, Acar N, Bron AM, Creuzot-Garcher CP, Bretillon L. Early adaptive response of the retina to a pro-diabetogenic diet: Impairment of cone response and gene expression changes in high-fructose fed rats. Exp Eye Res 2015; 135:37-46. [PMID: 25912194 DOI: 10.1016/j.exer.2015.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 11/17/2022]
Abstract
The lack of plasticity of neurons to respond to dietary changes, such as high fat and high fructose diets, by modulating gene and protein expression has been associated with functional and behavioral impairments that can have detrimental consequences. The inhibition of high fat-induced rewiring of hypothalamic neurons induced obesity. Feeding rodents with high fructose is a recognized and widely used model to trigger obesity and metabolic syndrome. However the adaptive response of the retina to short term feeding with high fructose is poorly documented. We therefore aimed to characterize both the functional and gene expression changes in the neurosensory retina of Brown Norway rats fed during 3 and 8 days with a 60%-rich fructose diet (n = 16 per diet and per time point). Glucose, insulin, leptin, triacylglycerols, total cholesterol, HDL-cholesterol, LDL-cholesterol and fructosamine were quantified in plasma (n = 8 in each group). Functionality of the inner retina was studied using scotopic single flash electroretinography (n = 8 in each group) and the individual response of rod and cone photoreceptors was determined using 8.02 Hz Flicker electroretinography (n = 8 in each group). Analysis of gene expression in the neurosensory retina was performed by Affymetrix genechips, and confirmed by RT-qPCR (n = 6 in each group). Elevated glycemia (+13%), insulinemia (+83%), and leptinemia (+172%) was observed after 8 days of fructose feeding. The cone photoreceptor response was altered at day 8 in high fructose fed rats (Δ = 0.5 log unit of light stimulus intensity). Affymetrix analysis of gene expression highlighted significant modulation of the pathways of eIF2 signaling and endoplasmic reticulum stress, regulation of eIF4 and p70S6K signaling, as well as mTOR signaling and mitochondrial dysfunction. RT-qPCR analysis confirmed the down regulation of Crystallins, Npy, Nid1 and Optc genes after 3 days of fructose feeding, and up regulation of End2. Meanwhile, a trend towards an increased expression of αA- and αB-crystallin proteins was observed at day 8. Our results are consistent with early alterations of the functioning and gene expression in the retina in a pro diabetogenic environment.
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Affiliation(s)
- Magalie Thierry
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France
| | - Bruno Pasquis
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France
| | - Bénédicte Buteau
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France
| | - Cynthia Fourgeux
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France
| | - Doulaye Dembele
- INSERM, UMR964 Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), F-67404 Illkirch, France; CNRS, UMR7104 Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), F-67404 Illkirch, France; Université de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), F-67404 Illkirch, France; IGBMC, Microarray and Sequencing Platform, F-67404 Illkirch, France
| | - Laurent Leclere
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France
| | - Ségolène Gambert-Nicot
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; University Hospital, Department of Clinical Chemistry, F-21000 Dijon, France
| | - Niyazi Acar
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France
| | - Alain M Bron
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; University Hospital, Department of Ophthalmology, F-21000 Dijon, France
| | - Catherine P Creuzot-Garcher
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; University Hospital, Department of Ophthalmology, F-21000 Dijon, France
| | - Lionel Bretillon
- INRA, UMR1324 Centre des Sciences du Goût et de l'Alimentation, Eye and Nutrition Research Group, F-21000 Dijon, France; CNRS, UMR6265 Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation, F-21000 Dijon, France.
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Walmsley L, Hanna L, Mouland J, Martial F, West A, Smedley AR, Bechtold DA, Webb AR, Lucas RJ, Brown TM. Colour as a signal for entraining the mammalian circadian clock. PLoS Biol 2015; 13:e1002127. [PMID: 25884537 PMCID: PMC4401556 DOI: 10.1371/journal.pbio.1002127] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 03/11/2015] [Indexed: 11/18/2022] Open
Abstract
Twilight is characterised by changes in both quantity (“irradiance”) and quality (“colour”) of light. Animals use the variation in irradiance to adjust their internal circadian clocks, aligning their behaviour and physiology with the solar cycle. However, it is currently unknown whether changes in colour also contribute to this entrainment process. Using environmental measurements, we show here that mammalian blue–yellow colour discrimination provides a more reliable method of tracking twilight progression than simply measuring irradiance. We next use electrophysiological recordings to demonstrate that neurons in the mouse suprachiasmatic circadian clock display the cone-dependent spectral opponency required to make use of this information. Thus, our data show that some clock neurons are highly sensitive to changes in spectral composition occurring over twilight and that this input dictates their response to changes in irradiance. Finally, using mice housed under photoperiods with simulated dawn/dusk transitions, we confirm that spectral changes occurring during twilight are required for appropriate circadian alignment under natural conditions. Together, these data reveal a new sensory mechanism for telling time of day that would be available to any mammalian species capable of chromatic vision. Environmental measurements and physiological recordings reveal that mice not only use changes in the intensity of sunlight to entrain their circadian clock, but also employ blue–yellow color discrimination to detect spectral changes associated with dawn and dusk. Animals use an internal brain clock to keep track of time and adjust their behaviour in anticipation of the coming day or night. To be useful, however, this clock must be synchronised to external time. Assessing external time is typically thought to rely on measuring large changes in ambient light intensity that occur over dawn/dusk. The colour of light also changes over these twilight transitions, but it is currently unknown whether such changes in colour are important for synchronising biological clocks to the solar cycle. Here we show that the mammalian blue–yellow colour discrimination axis provides a more reliable indication of twilight progression than a system solely measuring changes in light intensity. We go on to use electrical recordings from the brain clock to reveal the presence of many neurons that can track changes in blue–yellow colour occurring during natural twilight. Finally, using mice housed under lighting regimes with simulated dawn/dusk transitions, we show that changes in colour are required for appropriate biological timing with respect to the solar cycle. In sum, our data reveal a new sensory mechanism for estimating time of day that should be available to all mammals capable of chromatic vision, including humans.
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Affiliation(s)
- Lauren Walmsley
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Lydia Hanna
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Josh Mouland
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Franck Martial
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Alexander West
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Andrew R. Smedley
- School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, United Kingdom
| | - David A. Bechtold
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Ann R. Webb
- School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, United Kingdom
| | - Robert J. Lucas
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail: (RJL); (TMB)
| | - Timothy M. Brown
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail: (RJL); (TMB)
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Du W, Tao Y, Deng WT, Zhu P, Li J, Dai X, Zhang Y, Shi W, Liu X, Chiodo VA, Ding XQ, Zhao C, Michalakis S, Biel M, Zhang Z, Qu J, Hauswirth WW, Pang JJ. Vitreal delivery of AAV vectored Cnga3 restores cone function in CNGA3-/-/Nrl-/- mice, an all-cone model of CNGA3 achromatopsia. Hum Mol Genet 2015; 24:3699-707. [PMID: 25855802 DOI: 10.1093/hmg/ddv114] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/30/2015] [Indexed: 11/14/2022] Open
Abstract
The CNGA3(-/-)/Nrl(-/-) mouse is a cone-dominant model with Cnga3 channel deficiency, which partially mimics the all cone foveal structure of human achromatopsia 2 with CNGA3 mutations. Although subretinal (SR) AAV vector administration can transfect retinal cells efficiently, the injection-induced retinal detachment can cause retinal damage, particularly when SR vector bleb includes the fovea. We therefore explored whether cone function-structure could be rescued in CNGA3(-/-)/Nrl(-/-) mice by intravitreal (IVit) delivery of tyrosine to phenylalanine (Y-F) capsid mutant AAV8. We find that AAV-mediated CNGA3 expression can restore cone function and rescue structure following IVit delivery of AAV8 (Y447, 733F) vector. Rescue was assessed by restoration of the cone-mediated electroretinogram (ERG), optomotor responses, and cone opsin immunohistochemistry. Demonstration of gene therapy in a cone-dominant mouse model by IVit delivery provides a potential alternative vector delivery mode for safely transducing foveal cones in achromatopsia patients and in other human retinal diseases affecting foveal function.
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Affiliation(s)
- Wei Du
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Ye Tao
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Wen-Tao Deng
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Ping Zhu
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Jie Li
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Xufeng Dai
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA, School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Yuxin Zhang
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA, Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China
| | - Wei Shi
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Xuan Liu
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Vince A Chiodo
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Xi-Qin Ding
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Chen Zhao
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China
| | - Stylianos Michalakis
- Munich Center for Integrated Protein Science and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany and
| | - Martin Biel
- Munich Center for Integrated Protein Science and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany and
| | - Zuoming Zhang
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, Xi'an 710032, China
| | - Jia Qu
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China,
| | - William W Hauswirth
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA,
| | - Ji-Jing Pang
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA, School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China, Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China,
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Davis KE, Eleftheriou CG, Allen AE, Procyk CA, Lucas RJ. Melanopsin-derived visual responses under light adapted conditions in the mouse dLGN. PLoS One 2015; 10:e0123424. [PMID: 25822371 PMCID: PMC4379008 DOI: 10.1371/journal.pone.0123424] [Citation(s) in RCA: 27] [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: 09/12/2014] [Accepted: 02/24/2015] [Indexed: 01/16/2023] Open
Abstract
A direct projection from melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) reaches the primary visual thalamus (dorsal lateral geniculate nucleus; dLGN). The significance of this melanopsin input to the visual system is only recently being investigated. One unresolved question is the degree to which neurons in the dLGN could use melanopsin to track dynamic changes in light intensity under light adapted conditions. Here we set out to address this question. We were able to present full field steps visible only to melanopsin by switching between rod-isoluminant ‘yellow’ and ‘blue’ lights in a mouse lacking cone function (Cnga3-/-). In the retina these stimuli elicited melanopsin-like responses from a subset of ganglion cells. When presented to anaesthetised mice, we found that ~25-30% of visually responsive neurones in the contralateral dLGN responded to these melanopsin-isolating steps with small increases in firing rate. Such responses could be elicited even with fairly modest increases in effective irradiance (32% Michelson contrast for melanopsin). These melanopsin-driven responses were apparent at bright backgrounds (corresponding to twilight-daylight conditions), but their threshold irradiance was strongly dependent upon prior light exposure when stimuli were superimposed on a spectrally neutral ramping background light. While both onset and offset latencies were long for melanopsin-derived responses compared to those evoked by rods, there was great variability in these parameters with some cells responding to melanopsin steps in <1 s. These data indicate that a subset of dLGN units can employ melanopsin signals to detect modest changes in irradiance under photopic conditions.
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Affiliation(s)
- Katherine E. Davis
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail: (KED); (RJL)
| | | | - Annette E. Allen
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | | | - Robert J. Lucas
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail: (KED); (RJL)
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Venkatesh A, Ma S, Le YZ, Hall MN, Rüegg MA, Punzo C. Activated mTORC1 promotes long-term cone survival in retinitis pigmentosa mice. J Clin Invest 2015; 125:1446-58. [PMID: 25798619 DOI: 10.1172/jci79766] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/05/2015] [Indexed: 02/06/2023] Open
Abstract
Retinitis pigmentosa (RP) is an inherited photoreceptor degenerative disorder that results in blindness. The disease is often caused by mutations in genes that are specific to rod photoreceptors; however, blindness results from the secondary loss of cones by a still unknown mechanism. Here, we demonstrated that the mammalian target of rapamycin complex 1 (mTORC1) is required to slow the progression of cone death during disease and that constitutive activation of mTORC1 in cones is sufficient to maintain cone function and promote long-term cone survival. Activation of mTORC1 in cones enhanced glucose uptake, retention, and utilization, leading to increased levels of the key metabolite NADPH. Moreover, cone death was delayed in the absence of the NADPH-sensitive cell death protease caspase 2, supporting the contribution of reduced NADPH in promoting cone death. Constitutive activation of mTORC1 preserved cones in 2 mouse models of RP, suggesting that the secondary loss of cones is caused mainly by metabolic deficits and is independent of a specific rod-associated mutation. Together, the results of this study address a longstanding question in the field and suggest that activating mTORC1 in cones has therapeutic potential to prolong vision in RP.
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70
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Dai X, Zhang H, He Y, Qi Y, Chang B, Pang JJ. The frequency-response electroretinogram distinguishes cone and abnormal rod function in rd12 mice. PLoS One 2015; 10:e0117570. [PMID: 25706871 PMCID: PMC4338143 DOI: 10.1371/journal.pone.0117570] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 12/28/2014] [Indexed: 11/19/2022] Open
Abstract
Early studies on Rpe65 knockout mice reported that remaining visual function was attributable to cone function. However, this finding has been challenged more and more as time has passed. Electroretinograms (ERGs) showed that rd12 mice, a spontaneous animal model of RPE65 Leber’s congenital amaurosis, had sizeable photopic responses. Unfortunately, the recorded ERG waveform was difficult to interpret because of a remarkably delayed peak-time, which resembles a rod response more than a cone response. Here, we compare flicker ERGs in animals with normal rod and cone function (C57BL/6J mice), pure rod function (cpfl5 mice), and pure cone function (Rho-/- mice) under different adaptation levels and stimulus intensities. These responses were then compared with those obtained from rd12 mice. Our results showed that normal rods respond to low frequency flicker (5 and 15 Hz) and that normal cones respond to both low and high frequency flicker (5–35 Hz). As was seen in cpfl5 mice, rd12 mice had recordable responses to low frequency flicker (5 and 15Hz), but not to high frequency flicker (25 and 35 Hz). We hypothesize that abnormal rods may be the source of residual vision in rd12 mice, which is proved correct here with double mutant rd12mice. In this study, we show, for the first time, that frequency-response ERGs can effectively distinguish cone- and rod-driven responses in the rd12 mouse. It is another simple and valid method for evaluating the respective contributions of retinal rods and cones.
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Affiliation(s)
- Xufeng Dai
- Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
| | - Hua Zhang
- Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Ying He
- Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Yan Qi
- Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Ji-jing Pang
- Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
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71
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Zelinger L, Cideciyan AV, Kohl S, Schwartz SB, Rosenmann A, Eli D, Sumaroka A, Roman AJ, Luo X, Brown C, Rosin B, Blumenfeld A, Wissinger B, Jacobson SG, Banin E, Sharon D. Genetics and Disease Expression in the CNGA3 Form of Achromatopsia: Steps on the Path to Gene Therapy. Ophthalmology 2015; 122:997-1007. [PMID: 25616768 DOI: 10.1016/j.ophtha.2014.11.025] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 11/17/2014] [Accepted: 11/23/2014] [Indexed: 01/18/2023] Open
Abstract
PURPOSE Achromatopsia (ACHM) is a congenital, autosomal recessive retinal disease that manifests cone dysfunction, reduced visual acuity and color vision, nystagmus, and photoaversion. Five genes are known causes of ACHM. The present study took steps toward performing a trial of gene therapy in ACHM by characterizing the genetics of ACHM in Israel and the Palestinian Territories and analyzing retinal function and structure in CNGA3 ACHM patients from the Israeli-Palestinian population and US patients with other origins. DESIGN Case series study. PARTICIPANTS Patients with clinically suspected ACHM, cone dysfunction phenotypes, and unaffected family members were included. The protocol was approved by the local institutional review board and informed consent was obtained from all participants. METHODS Genetic analyses included homozygosity mapping and exome sequencing. Phenotype was assessed with electroretinography (ERG), optical coherence tomography, psychophysics, and photoaversion testing. MAIN OUTCOME MEASURES Single nucleotide polymorphism microarray, exome analysis, DNA sequence analysis, visual function testing including ERG, and photoaversion. RESULTS We identified 148 ACHM patients from 57 Israeli and Palestinian families; there were 16 CNGA3 mutations (5 novel) in 41 families and 5 CNGB3 mutations (1 novel) in 8 families. Two CNGA3 founder mutations underlie >50% of cases. These mutations lead to a high ACHM prevalence of ∼1:5000 among Arab-Muslims residing in Jerusalem. Rod ERG abnormalities (in addition to cone dysfunction) were detected in 59% of patients. Retinal structure in CNGA3 ACHM patients revealed persistent but abnormal foveal cones. Under dark- and light-adapted conditions, patients use rod-mediated pathways. Photoaversion was readily demonstrated with transition from the dark to a dim light background. CONCLUSIONS Among Israeli and Palestinian patients, CNGA3 mutations are the leading cause of ACHM. Retinal structural results support the candidacy of CNGA3 ACHM for clinical trials for therapy of cone photoreceptors. Efficacy outcome measures would include chromatic light-adapted psychophysics, with attention to the photoreceptor basis of the response, and quantitation of photoaversion.
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Affiliation(s)
- Lina Zelinger
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Artur V Cideciyan
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Sharon B Schwartz
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ada Rosenmann
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Dalia Eli
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Alexander Sumaroka
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alejandro J Roman
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Xunda Luo
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cassondra Brown
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Boris Rosin
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Anat Blumenfeld
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
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Arango-Gonzalez B, Trifunović D, Sahaboglu A, Kranz K, Michalakis S, Farinelli P, Koch S, Koch F, Cottet S, Janssen-Bienhold U, Dedek K, Biel M, Zrenner E, Euler T, Ekström P, Ueffing M, Paquet-Durand F. Identification of a common non-apoptotic cell death mechanism in hereditary retinal degeneration. PLoS One 2014; 9:e112142. [PMID: 25392995 PMCID: PMC4230983 DOI: 10.1371/journal.pone.0112142] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 10/13/2014] [Indexed: 01/10/2023] Open
Abstract
Cell death in neurodegenerative diseases is often thought to be governed by apoptosis; however, an increasing body of evidence suggests the involvement of alternative cell death mechanisms in neuronal degeneration. We studied retinal neurodegeneration using 10 different animal models, covering all major groups of hereditary human blindness (rd1, rd2, rd10, Cngb1 KO, Rho KO, S334ter, P23H, Cnga3 KO, cpfl1, Rpe65 KO), by investigating metabolic processes relevant for different forms of cell death. We show that apoptosis plays only a minor role in the inherited forms of retinal neurodegeneration studied, where instead, a non-apoptotic degenerative mechanism common to all mutants is of major importance. Hallmark features of this pathway are activation of histone deacetylase, poly-ADP-ribose-polymerase, and calpain, as well as accumulation of cyclic guanosine monophosphate and poly-ADP-ribose. Our work thus demonstrates the prevalence of alternative cell death mechanisms in inherited retinal degeneration and provides a rational basis for the design of mutation-independent treatments.
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Affiliation(s)
| | - Dragana Trifunović
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Ayse Sahaboglu
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Katharina Kranz
- Department of Neurobiology, University of Oldenburg, Oldenburg, Germany
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Pietro Farinelli
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Division of Ophthalmology, Department of Clinical Sciences, University of Lund, Lund, Sweden
| | - Susanne Koch
- Center for Integrated Protein Science Munich and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Fred Koch
- Center for Integrated Protein Science Munich and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Sandra Cottet
- Institute for Research in Ophthalmology, Sion, Switzerland
| | | | - Karin Dedek
- Department of Neurobiology, University of Oldenburg, Oldenburg, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Eberhart Zrenner
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Centre for Integrative Neuroscience, University of Tuebingen, Tuebingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Centre for Integrative Neuroscience, University of Tuebingen, Tuebingen, Germany
| | - Per Ekström
- Division of Ophthalmology, Department of Clinical Sciences, University of Lund, Lund, Sweden
| | - Marius Ueffing
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
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Szikra T, Trenholm S, Drinnenberg A, Jüttner J, Raics Z, Farrow K, Biel M, Awatramani G, Clark DA, Sahel JA, da Silveira RA, Roska B. Rods in daylight act as relay cells for cone-driven horizontal cell-mediated surround inhibition. Nat Neurosci 2014; 17:1728-35. [PMID: 25344628 DOI: 10.1038/nn.3852] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 09/29/2014] [Indexed: 12/18/2022]
Abstract
Vertebrate vision relies on two types of photoreceptors, rods and cones, which signal increments in light intensity with graded hyperpolarizations. Rods operate in the lower range of light intensities while cones operate at brighter intensities. The receptive fields of both photoreceptors exhibit antagonistic center-surround organization. Here we show that at bright light levels, mouse rods act as relay cells for cone-driven horizontal cell-mediated surround inhibition. In response to large, bright stimuli that activate their surrounds, rods depolarize. Rod depolarization increases with stimulus size, and its action spectrum matches that of cones. Rod responses at high light levels are abolished in mice with nonfunctional cones and when horizontal cells are reversibly inactivated. Rod depolarization is conveyed to the inner retina via postsynaptic circuit elements, namely the rod bipolar cells. Our results show that the retinal circuitry repurposes rods, when they are not directly sensing light, to relay cone-driven surround inhibition.
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Affiliation(s)
- Tamas Szikra
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Stuart Trenholm
- 1] Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland. [2] Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Antonia Drinnenberg
- 1] Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland. [2] University of Basel, Basel, Switzerland
| | - Josephine Jüttner
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Zoltan Raics
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Karl Farrow
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Martin Biel
- Department of Pharmacy-Center for Drug Research, Center for Integrated Protein Science Munich, Ludwig-Maximilians University, Munich, Germany
| | - Gautam Awatramani
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Damon A Clark
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA
| | - José-Alain Sahel
- 1] Université Pierre et Marie Curie-Sorbonne Universités, Institut de la Vision, Paris, France. [2] Institut national de la santé et de la recherche médicale, Institut de la Vision, Paris, France. [3] Centre national de la recherche scientifique, Institut de la Vision, Paris, France. [4] Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Département Hospitalo-Universitaire ViewMaintain, Paris, France. [5] Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
| | - Rava Azeredo da Silveira
- 1] Department of Physics, École Normale Supérieure, Paris, France. [2] Laboratoire de Physique Statistique, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Université Denis Diderot, Paris, France
| | - Botond Roska
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
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74
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Ezra-Elia R, Banin E, Honig H, Rosov A, Obolensky A, Averbukh E, Hauswirth WW, Gootwine E, Ofri R. Flicker cone function in normal and day blind sheep: a large animal model for human achromatopsia caused by CNGA3 mutation. Doc Ophthalmol 2014; 129:141-50. [PMID: 25204753 DOI: 10.1007/s10633-014-9458-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 09/01/2014] [Indexed: 11/30/2022]
Abstract
PURPOSE Recently we reported on day blindness in sheep caused by a mutation in the CNGA3 gene, thus making affected sheep a naturally occurring large animal model for therapeutic intervention in CNGA3 achromatopsia patients. The purpose of this study was to characterize flicker cone function in normal and day blind sheep, with the aim of generating a normative data base for ongoing gene therapy studies. METHODS Electoretinographic (ERG) cone responses were evoked with full-field conditions in 10 normal, 6 heterozygous carriers and 36 day blind sheep. Following light adaptation (10 min, 30 cd/m(2)), responses were recorded at four increasing light intensities (1, 2.5, 5 and 10 cd s/m(2)). At each of these intensities, a single photopic flash response followed by 8 cone flicker responses (10-80 Hz) was recorded. Results were used to generate a normative data base for the three groups. Differences between day blind and normal control animals were tested in two age-matched groups (n = 10 per group). RESULTS The normal sheep cone ERG wave is bipartite in nature, with critical flicker fusion frequency (CFF) >80 Hz. In all four flash intensities, the single photopic flash a-wave and b-wave amplitudes were significantly lower (p < 0.005), and implicit times significantly delayed (p < 0.0001), in day blind animals. In all four flash intensities, CFF values were significantly lower (p < 0.0001) in day blind sheep. CONCLUSIONS Cone function is severely depressed in day blind sheep. Our results will provide a normative data base for ongoing gene therapy studies.
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Affiliation(s)
- Raaya Ezra-Elia
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, PO Box 12, 7610001, Rehovot, Israel
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75
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Zein WM, Jeffrey BG, Wiley HE, Turriff AE, Tumminia SJ, Tao W, Bush RA, Marangoni D, Wen R, Wei LL, Sieving PA. CNGB3-achromatopsia clinical trial with CNTF: diminished rod pathway responses with no evidence of improvement in cone function. Invest Ophthalmol Vis Sci 2014; 55:6301-8. [PMID: 25205868 DOI: 10.1167/iovs.14-14860] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Ciliary neurotrophic factor (CNTF) protects rod photoreceptors from retinal degenerative disease in multiple nonhuman models. Thus far, CNTF has failed to demonstrate rod protection in trials for human retinitis pigmentosa. Recently, CNTF was found to improve cone photoreceptor function in a canine CNGB3 achromatopsia model. This study explores whether this finding translates to humans with CNGB3 achromatopsia. METHODS A five-subject, open-label Phase I/II study was initiated by implanting intraocular microcapsules releasing CNTF (nominally 20 ng/d) into one eye each of CNGB3 achromat participants. Fellow eyes served as untreated controls. Subjects were followed for 1 year. RESULTS Pupil constriction in treated eyes gave evidence of intraocular CNTF release. Additionally, scotopic ERG responses were reduced, and dark-adapted psychophysical absolute thresholds were increased, attributable to diminished rod or rod pathway activity. Optical coherence tomography revealed that the cone-rich fovea underwent structural changes as the foveal hyporeflective zone (HRZ) became diminished in CNTF-treated eyes. No objectively measurable enhancement of cone function was found by assessments of visual acuity, mesopic increment sensitivity threshold, or the photopic ERG. Careful measurements of color hue discrimination showed no change. Nonetheless, subjects reported beneficial changes of visual function in the treated eyes, including reduced light sensitivity and aversion to bright light, which may trace to decreased effective ambient light from the pupillary constriction; further they noted slowed adaptation to darkness, consistent with CNTF action on rod photoreceptors. CONCLUSIONS Ciliary neurotrophic factor did not measurably enhance cone function, which reveals a species difference between human and canine CNGB3 cones in response to CNTF. (ClinicalTrials.gov number, NCT01648452.).
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Affiliation(s)
- Wadih M Zein
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Brett G Jeffrey
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Henry E Wiley
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Amy E Turriff
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Santa J Tumminia
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Weng Tao
- Neurotech Pharmaceuticals, Inc., Cumberland, Rhode Island, United States
| | - Ronald A Bush
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Dario Marangoni
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States Department of Biotechnology and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy
| | - Rong Wen
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami, Miller School of Medicine, Miami, Florida, United States
| | - Lisa L Wei
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Paul A Sieving
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
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Samardzija M, Grimm C. Mouse models for cone degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:567-73. [PMID: 24664745 DOI: 10.1007/978-1-4614-3209-8_72] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Loss of cone vision has devastating effects on everyday life. Even though much effort has been made to understand cone physiology and pathophysiology, no successful therapies are available for patients suffering from cone disorders. As complex retinal interactions cannot be studied in vitro, utilization of different animal models is inevitable. Due to recent advances in transgenesis, mice became the most popular animal model to study human diseases, also in ophthalmology. While there are similarities in retinal anatomy and pathophysiology between mice and humans, there are also differences, most importantly the lack of a cone-rich macula in mice. Instead, cones in mice are rare and distributed over the whole retina, which makes the analysis of cone pathophysiology very difficult in these animals. This hindrance is one of the reasons why our understanding of rod pathophysiological processes is much more advanced. Recently, however, the sparseness of cones was overcome by the generation of the Nrl (- / -) mouse that expresses only cone photoreceptors in the retina. This paper will give a brief overview of some of the known mouse models to study cone degeneration and discuss the current knowledge gained from the analysis of these models.
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Affiliation(s)
- Marijana Samardzija
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Wagistr 14 Schlieren, 8952, Zurich, Switzerland,
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77
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Buffone MG, Wertheimer EV, Visconti PE, Krapf D. Central role of soluble adenylyl cyclase and cAMP in sperm physiology. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2610-20. [PMID: 25066614 DOI: 10.1016/j.bbadis.2014.07.013] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 11/15/2022]
Abstract
Cyclic adenosine 3',5'-monophosphate (cAMP), the first second messenger to be described, plays a central role in cell signaling in a wide variety of cell types. Over the last decades, a wide body of literature addressed the different roles of cAMP in cell physiology, mainly in response to neurotransmitters and hormones. cAMP is synthesized by a wide variety of adenylyl cyclases that can generally be grouped in two types: transmembrane adenylyl cyclase and soluble adenylyl cyclases. In particular, several aspects of sperm physiology are regulated by cAMP produced by a single atypical adenylyl cyclase (Adcy10, aka sAC, SACY). The signature that identifies sAC among other ACs, is their direct stimulation by bicarbonate. The essential nature of cAMP in sperm function has been demonstrated using gain of function as well as loss of function approaches. This review unifies state of the art knowledge of the role of cAMP and those enzymes involved in cAMP signaling pathways required for the acquisition of fertilizing capacity of mammalian sperm. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- Mariano G Buffone
- Instituto de Biología y Medicina Experimental, National Research Council of Argentina (CONICET), Buenos Aires, Argentina
| | - Eva V Wertheimer
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Facultad de Medicina, Universidad de Buenos Aires, Argentina
| | - Pablo E Visconti
- Department of Veterinary and Animal Sciences, ISB, University of Massachusetts, Amherst, MA 01003, USA.
| | - Dario Krapf
- Instituto de Biología Molecular y Celular de Rosario (CONICET), UNR, Rosario, Argentina; Facultad de Ciencias Bioquímicas y Farmacéuticas, UNR, Rosario, Argentina
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78
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Roosing S, Thiadens AAHJ, Hoyng CB, Klaver CCW, den Hollander AI, Cremers FPM. Causes and consequences of inherited cone disorders. Prog Retin Eye Res 2014; 42:1-26. [PMID: 24857951 DOI: 10.1016/j.preteyeres.2014.05.001] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 04/29/2014] [Accepted: 05/06/2014] [Indexed: 11/18/2022]
Abstract
Hereditary cone disorders (CDs) are characterized by defects of the cone photoreceptors or retinal pigment epithelium underlying the macula, and include achromatopsia (ACHM), cone dystrophy (COD), cone-rod dystrophy (CRD), color vision impairment, Stargardt disease (STGD) and other maculopathies. Forty-two genes have been implicated in non-syndromic inherited CDs. Mutations in the 5 genes implicated in ACHM explain ∼93% of the cases. On the contrary, only 21% of CRDs (17 genes) and 25% of CODs (8 genes) have been elucidated. The fact that the large majority of COD and CRD-associated genes are yet to be discovered hints towards the existence of unknown cone-specific or cone-sensitive processes. The ACHM-associated genes encode proteins that fulfill crucial roles in the cone phototransduction cascade, which is the most frequently compromised (10 genes) process in CDs. Another 7 CD-associated proteins are required for transport processes towards or through the connecting cilium. The remaining CD-associated proteins are involved in cell membrane morphogenesis and maintenance, synaptic transduction, and the retinoid cycle. Further novel genes are likely to be identified in the near future by combining large-scale DNA sequencing and transcriptomics technologies. For 31 of 42 CD-associated genes, mammalian models are available, 14 of which have successfully been used for gene augmentation studies. However, gene augmentation for CDs should ideally be developed in large mammalian models with cone-rich areas, which are currently available for only 11 CD genes. Future research will aim to elucidate the remaining causative genes, identify the molecular mechanisms of CD, and develop novel therapies aimed at preventing vision loss in individuals with CD in the future.
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Affiliation(s)
- Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | | | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Caroline C W Klaver
- Department of Ophthalmology Erasmus Medical Centre, 3000 CA, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus Medical Centre, 3000 CA, Rotterdam, The Netherlands
| | - Anneke I den Hollander
- Department of Human Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, PO Box 9101, 6500 HB, Nijmegen, The Netherlands; Department of Ophthalmology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
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Greenberg JP, Sherman J, Zweifel SA, Chen RWS, Duncker T, Kohl S, Baumann B, Wissinger B, Yannuzzi LA, Tsang SH. Spectral-domain optical coherence tomography staging and autofluorescence imaging in achromatopsia. JAMA Ophthalmol 2014; 132:437-45. [PMID: 24504161 PMCID: PMC4423754 DOI: 10.1001/jamaophthalmol.2013.7987] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Evidence is mounting that achromatopsia is a progressive retinal degeneration, and treatments for this condition are on the horizon. OBJECTIVES To categorize achromatopsia into clinically identifiable stages using spectral-domain optical coherence tomography and to describe fundus autofluorescence imaging in this condition. DESIGN, SETTING, AND PARTICIPANTS A prospective observational study was performed between 2010 and 2012 at the Edward S. Harkness Eye Institute, New York-Presbyterian Hospital. Participants included 17 patients (aged 10-62 years) with full-field electroretinography-confirmed achromatopsia. MAIN OUTCOMES AND MEASURES Spectral-domain optical coherence tomography features and staging system, fundus autofluorescence and near-infrared reflectance features and their correlation to optical coherence tomography, and genetic mutations served as the outcomes and measures. RESULTS Achromatopsia was categorized into 5 stages on spectral-domain optical coherence tomography: stage 1 (2 patients [12%]), intact outer retina; stage 2 (2 patients [12%]), inner segment ellipsoid line disruption; stage 3 (5 patients [29%]), presence of an optically empty space; stage 4 (5 patients [29%]), optically empty space with partial retinal pigment epithelium disruption; and stage 5 (3 patients [18%]), complete retinal pigment epithelium disruption and/or loss of the outer nuclear layer. Stage 1 patients showed isolated hyperreflectivity of the external limiting membrane in the fovea, and the external limiting membrane was hyperreflective above each optically empty space. On near infrared reflectance imaging, the fovea was normal, hyporeflective, or showed both hyporeflective and hyperreflective features. All patients demonstrated autofluorescence abnormalities in the fovea and/or parafovea: 9 participants (53%) had reduced or absent autofluorescence surrounded by increased autofluorescence, 4 individuals (24%) showed only reduced or absent autofluorescence, 3 patients (18%) displayed only increased autofluorescence, and 1 individual (6%) exhibited decreased macular pigment contrast. Inner segment ellipsoid line loss generally correlated with the area of reduced autofluorescence, but hyperautofluorescence extended into this region in 2 patients (12%). Bilateral coloboma-like atrophic macular lesions were observed in 1 patient (6%). Five novel mutations were identified (4 in the CNGA3 gene and 1 in the CNGB3 gene). CONCLUSIONS AND RELEVANCE Achromatopsia often demonstrates hyperautofluorescence suggestive of progressive retinal degeneration. The proposed staging system facilitates classification of the disease into different phases of progression and may have therapeutic implications.
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Affiliation(s)
| | - Jerome Sherman
- Department of Clinical Sciences, State University of New York College of Optometry, New York, New York
| | - Sandrine A Zweifel
- The Vitreous, Retina, Macula Consultants of New York, New York4The LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Hospital, New York, New York
| | - Royce W S Chen
- Department of Ophthalmology, Columbia University, New York, New York
| | - Tobias Duncker
- Department of Ophthalmology, Columbia University, New York, New York
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Britta Baumann
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Lawrence A Yannuzzi
- The Vitreous, Retina, Macula Consultants of New York, New York4The LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Hospital, New York, New York
| | - Stephen H Tsang
- Department of Ophthalmology, Columbia University, New York, New York6Bernard and Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, New York 7Department of Pathology and Cell Biology, Columbia Un
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cGMP accumulation causes photoreceptor degeneration in CNG channel deficiency: evidence of cGMP cytotoxicity independently of enhanced CNG channel function. J Neurosci 2013; 33:14939-48. [PMID: 24027293 DOI: 10.1523/jneurosci.0909-13.2013] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Photoreceptor cyclic nucleotide-gated (CNG) channels regulate Ca(2+) influx in rod and cone photoreceptors. cGMP, the native ligand of the photoreceptor CNG channels, has been associated with cytotoxicity when its levels rise above normal due to defects in photoreceptor phosphodiesterase (PDE6) or regulation of retinal guanylyl cyclase (retGC). We found a massive accumulation of cGMP in CNGA3-deficient retina and investigated whether cGMP accumulation plays a role in cone degeneration in CNG channel deficiency. The time course study showed that the retinal cGMP level in Cnga3(-/-);Nrl(-/-) mice with CNGA3 deficiency on a cone-dominant background was sharply increased at postnatal day 8 (P8), peaked around P10-P15, remained high through P30-P60, and returned to near control level at P90. This elevation pattern correlated with photoreceptor apoptotic death, which peaked around P15-P20. In Cnga3(-/-);Gucy2e(-/-) mice lacking retGC1, cone density and expression levels of cone-specific proteins were significantly increased compared with Cnga3(-/-), consistent with a role of cGMP accumulation as the major contributor to cone death caused by CNG channel deficiency. The activity and expression levels of cGMP-dependent protein kinase G (PKG) were significantly increased in Cnga3(-/-);Nrl(-/-) retina compared with Nrl(-/-), suggesting an involvement of PKG regulation in cell death. Our results indicate that cGMP accumulation in photoreceptors can itself exert cytotoxic effect in cones, independently of CNG channel activity and Ca(2+) influx.
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81
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Fahim AT, Khan NW, Zahid S, Schachar IH, Branham K, Kohl S, Wissinger B, Elner VM, Heckenlively JR, Jayasundera T. Diagnostic fundus autofluorescence patterns in achromatopsia. Am J Ophthalmol 2013; 156:1211-1219.e2. [PMID: 23972307 DOI: 10.1016/j.ajo.2013.06.033] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 06/23/2013] [Accepted: 06/24/2013] [Indexed: 01/10/2023]
Abstract
PURPOSE To describe the unique diagnostic fundus autofluorescence (FAF) patterns in patients with achromatopsia and the associated findings on optical coherence tomography (OCT). DESIGN Observational case series. METHODS We evaluated 10 patients with achromatopsia by means of best-corrected visual acuity (BCVA), ophthalmoscopy, Goldmann visual field, full-field electroretinography (ffERG), OCT, and FAF photography. FAF patterns were compared with patient age and foveal changes on OCT. RESULTS Patients fell into two dichotomous age groups at the time of evaluation: six patients ranged from 11 to 23 years of age, and 3 patients ranged from 52 to 63 years of age. All patients had severely reduced photopic ffERG responses, including those exhibiting preserved foveal structure on OCT. The younger patients had absent to mild foveal atrophy on OCT, and four of the six demonstrated foveal and parafoveal hyperfluorescence on FAF. In addition, a 7-month-old child with compound heterozygous mutations in CNGA3 demonstrated similar foveal hyperfluorescence. The older patients demonstrated advanced foveal atrophy and punched-out foveal hypofluorescence with discrete borders on FAF imaging corresponding to the area of outer retinal cavitation on OCT. CONCLUSIONS Foveal hyperfluorescence is an early sign of achromatopsia that can aid in clinical diagnosis. In our cohort, patients with achromatopsia demonstrated age-dependent changes in FAF, which are likely to be progressive and to correlate with foveal atrophy and cavitation on OCT. This finding may be useful in charting the natural course of the disease and in defining a therapeutic window for treatment.
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Affiliation(s)
- Abigail T Fahim
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
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Tanimoto N, Sothilingam V, Gloeckner G, Bryda EC, Humphries P, Biel M, Seeliger MW. Auditory event-related signals in mouse ERG recordings. Doc Ophthalmol 2013; 128:25-32. [PMID: 24221507 DOI: 10.1007/s10633-013-9417-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 11/06/2013] [Indexed: 11/24/2022]
Abstract
PURPOSE In murine disease models, particularly in cases when retinal electrical activity is reduced, an event-related component becomes apparent that does not change with the stimulus intensity in electroretinogram (ERG) recordings. In this work, we show that this electric component is evoked by the sound of the flash discharge rather than the light flash itself. METHODS Wild-type mice (C57BL/6), mice with rod function only (Cnga3 (-/-)), mice lacking any photoreceptor function (Cnga3 (-/-) rho (-/-)), and mice with no auditory function (Cdh23 (vAlb/vAlb) ) were examined with Xenon flash ERG systems. An acoustic noise generator was used to mask discharge sounds. RESULTS ERG recording modalities were identified where usually no discernible response can be elicited. These include photopic conditions in Cnga3 (-/-) mice, photopic conditions together with very low stimulus intensities in C57BL/6 mice, and both scotopic and photopic conditions in Cnga3 (-/-) rho (-/-) mice. However, in all of these cases, small signals, featuring an initial a-wave like deflection at about 20 ms and a subsequent b-wave like deflection peaking at about 40 ms after the flash, were detected. In contrast, such signals could not be detected in deaf Cdh23 (vAlb/vAlb) mice. Furthermore, masking the Xenon discharge sound by continuous acoustic noise led to a loss of the event-related signals in a reversible manner. CONCLUSIONS We could identify an auditory event-related component, presumably resembling auditory evoked potentials, as a major source of ERG signals of non-visual origin in mice. This finding may be of particular importance for the analysis and interpretation of ERG data in mice with reduced visual responses.
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Affiliation(s)
- Naoyuki Tanimoto
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University, Schleichstr. 4/3, 72076, Tübingen, Germany,
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Podda MV, Grassi C. New perspectives in cyclic nucleotide-mediated functions in the CNS: the emerging role of cyclic nucleotide-gated (CNG) channels. Pflugers Arch 2013; 466:1241-57. [PMID: 24142069 DOI: 10.1007/s00424-013-1373-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 09/27/2013] [Accepted: 09/28/2013] [Indexed: 01/07/2023]
Abstract
Cyclic nucleotides play fundamental roles in the central nervous system (CNS) under both physiological and pathological conditions. The impact of cAMP and cGMP signaling on neuronal and glial cell functions has been thoroughly characterized. Most of their effects have been related to cyclic nucleotide-dependent protein kinase activity. However, cyclic nucleotide-gated (CNG) channels, first described as key mediators of sensory transduction in retinal and olfactory receptors, have been receiving increasing attention as possible targets of cyclic nucleotides in the CNS. In the last 15 years, consistent evidence has emerged for their expression in neurons and astrocytes of the rodent brain. Far less is known, however, about the functional role of CNG channels in these cells, although several of their features, such as Ca(2+) permeability and prolonged activation in the presence of cyclic nucleotides, make them ideal candidates for mediators of physiological functions in the CNS. Here, we review literature suggesting the involvement of CNG channels in a number of CNS cellular functions (e.g., regulation of membrane potential, neuronal excitability, and neurotransmitter release) as well as in more complex phenomena, like brain plasticity, adult neurogenesis, and pain sensitivity. The emerging picture is that functional and dysfunctional cyclic nucleotide signaling in the CNS has to be reconsidered including CNG channels among possible targets. However, concerted efforts and multidisciplinary approaches are still needed to get more in-depth knowledge in this field.
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Affiliation(s)
- Maria Vittoria Podda
- Institute of Human Physiology, Medical School, Università Cattolica, Largo Francesco Vito 1, 00168, Rome, Italy
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84
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The thermosensitive potassium channel TREK-1 contributes to coolness-evoked responses of Grueneberg ganglion neurons. Cell Mol Neurobiol 2013; 34:113-22. [PMID: 24101433 DOI: 10.1007/s10571-013-9992-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/19/2013] [Indexed: 10/26/2022]
Abstract
Neurons of the Grueneberg ganglion (GG) residing in the vestibule of the murine nose are activated by cool ambient temperatures. Activation of thermosensory neurons is usually mediated by thermosensitive ion channels of the transient receptor potential (TRP) family. However, there is no evidence for the expression of thermo-TRPs in the GG, suggesting that GG neurons utilize distinct mechanisms for their responsiveness to cool temperatures. In search for proteins that render GG neurons responsive to coolness, we have investigated whether TREK/TRAAK channels may play a role; in heterologous expression systems, these potassium channels have been previously found to close upon exposure to coolness, leading to a membrane depolarization. The results of the present study indicate that the thermosensitive potassium channel TREK-1 is expressed in those GG neurons that are responsive to cool temperatures. Studies analyzing TREK-deficient mice revealed that coolness-evoked responses of GG neurons were clearly attenuated in these animals compared with wild-type conspecifics. These data suggest that TREK-1 channels significantly contribute to the responsiveness of GG neurons to cool temperatures, further supporting the concept that TREK channels serve as thermoreceptors in sensory cells. Moreover, the present findings provide the first evidence of how thermosensory GG neurons are activated by given temperature stimuli in the absence of thermo-TRPs.
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85
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Schön C, Biel M, Michalakis S. Gene replacement therapy for retinal CNG channelopathies. Mol Genet Genomics 2013; 288:459-67. [DOI: 10.1007/s00438-013-0766-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 06/25/2013] [Indexed: 12/20/2022]
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86
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Cho KI, Haque M, Wang J, Yu M, Hao Y, Qiu S, Pillai ICL, Peachey NS, Ferreira PA. Distinct and atypical intrinsic and extrinsic cell death pathways between photoreceptor cell types upon specific ablation of Ranbp2 in cone photoreceptors. PLoS Genet 2013; 9:e1003555. [PMID: 23818861 PMCID: PMC3688534 DOI: 10.1371/journal.pgen.1003555] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 04/23/2013] [Indexed: 12/26/2022] Open
Abstract
Non-autonomous cell-death is a cardinal feature of the disintegration of neural networks in neurodegenerative diseases, but the molecular bases of this process are poorly understood. The neural retina comprises a mosaic of rod and cone photoreceptors. Cone and rod photoreceptors degenerate upon rod-specific expression of heterogeneous mutations in functionally distinct genes, whereas cone-specific mutations are thought to cause only cone demise. Here we show that conditional ablation in cone photoreceptors of Ran-binding protein-2 (Ranbp2), a cell context-dependent pleiotropic protein linked to neuroprotection, familial necrotic encephalopathies, acute transverse myelitis and tumor-suppression, promotes early electrophysiological deficits, subcellular erosive destruction and non-apoptotic death of cones, whereas rod photoreceptors undergo cone-dependent non-autonomous apoptosis. Cone-specific Ranbp2 ablation causes the temporal activation of a cone-intrinsic molecular cascade highlighted by the early activation of metalloproteinase 11/stromelysin-3 and up-regulation of Crx and CoREST, followed by the down-modulation of cone-specific phototransduction genes, transient up-regulation of regulatory/survival genes and activation of caspase-7 without apoptosis. Conversely, PARP1+-apoptotic rods develop upon sequential activation of caspase-9 and caspase-3 and loss of membrane permeability. Rod photoreceptor demise ceases upon cone degeneration. These findings reveal novel roles of Ranbp2 in the modulation of intrinsic and extrinsic cell death mechanisms and pathways. They also unveil a novel spatiotemporal paradigm of progression of neurodegeneration upon cell-specific genetic damage whereby a cone to rod non-autonomous death pathway with intrinsically distinct cell-type death manifestations is triggered by cell-specific loss of Ranbp2. Finally, this study casts new light onto cell-death mechanisms that may be shared by human dystrophies with distinct retinal spatial signatures as well as with other etiologically distinct neurodegenerative disorders. The secondary demise of healthy neurons upon the degeneration of neurons harboring primary genetic defect(s) is hallmark to neurodegenerative diseases. However, the factors and mechanisms driving these cell-death processes are not understood, a severe limitation which has hampered the therapeutic development of neuroprotective approaches. The neuroretina is comprised of two main types of photoreceptor neurons, rods and cones. These undergo degeneration upon heterogeneous mutations or environmental stressors and the underlying diseases present conspicuous spatiotemporal pathological signatures whose molecular bases are not understood. We employed the multifunctional protein, Ran-binding protein-2 (Ranbp2), which is implicated in cell-type and stress-dependent clinical manifestations, to examine its role(s) in primary and secondary photoreceptor death mechanisms upon its specific loss in cones. Contrary to prior findings, we found that dying cones can trigger the loss of healthy rods. This process arises by the immediate activation of novel Ranbp2-responsive factors and downstream cascade events in cones that promote extrinsically the demise of rods. The mechanisms of rod and cone demise are molecularly distinct. Collectively, the data uncover distinct Ranbp2 roles in intrinsic and extrinsic cell-death and will likely contribute to our understanding of the spatiotemporal onset and progression of diseases affecting photoreceptor mosaics and other neural networks.
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Affiliation(s)
- Kyoung-in Cho
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - MdEmdadul Haque
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jessica Wang
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Sunny Qiu
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Indulekha C. L. Pillai
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Neal S. Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
- Research Service, Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Paulo A. Ferreira
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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87
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Ma H, Thapa A, Morris LM, Michalakis S, Biel M, Frank MB, Bebak M, Ding XQ. Loss of cone cyclic nucleotide-gated channel leads to alterations in light response modulating system and cellular stress response pathways: a gene expression profiling study. Hum Mol Genet 2013; 22:3906-19. [PMID: 23740940 DOI: 10.1093/hmg/ddt245] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The cone photoreceptor cyclic nucleotide-gated (CNG) channel is essential for central and color vision and visual acuity. Mutations in the channel subunits CNGA3 and CNGB3 are associated with achromatopsia and cone dystrophy. We investigated the gene expression profiles in mouse retina with CNG channel deficiency using whole genome expression microarrays. As cones comprise only 2 to 3% of the total photoreceptor population in the wild-type mouse retina, the mouse lines with CNG channel deficiency on a cone-dominant background, i.e. Cnga3-/-/Nrl-/- and Cngb3-/-/Nrl-/- mice, were used in our study. Comparative data analysis revealed a total of 105 genes altered in Cnga3-/-/Nrl-/- and 92 in Cngb3-/-/Nrl-/- retinas, relative to Nrl-/- retinas, with 27 genes changed in both genotypes. The differentially expressed genes primarily encode proteins associated with cell signaling, cellular function maintenance and gene expression. Ingenuity pathway analysis (IPA) identified 26 and 9 canonical pathways in Cnga3-/-/Nrl-/- and Cngb3-/-/Nrl-/- retinas, respectively, with 6 pathways being shared. The shared pathways include phototransduction, cAMP/PKA-mediated signaling, endothelin signaling, and EIF2/endoplasmic reticulum (ER) stress, whereas the IL-1, CREB, and purine metabolism signaling were found to specifically associate with Cnga3 deficiency. Thus, CNG channel deficiency differentially regulates genes that affect cell processes such as phototransduction, cellular survival and gene expression, and such regulations play a crucial role(s) in the retinal adaptation to impaired cone phototransduction. Though lack of Cnga3 and Cngb3 shares many common pathways, deficiency of Cnga3 causes more significant alterations in gene expression. This work provides insights into how cones respond to impaired phototransduction at the gene expression levels.
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88
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Michalakis S, Schäferhoff K, Spiwoks-Becker I, Zabouri N, Koch S, Koch F, Bonin M, Biel M, Haverkamp S. Characterization of neurite outgrowth and ectopic synaptogenesis in response to photoreceptor dysfunction. Cell Mol Life Sci 2013; 70:1831-47. [PMID: 23269435 PMCID: PMC11113940 DOI: 10.1007/s00018-012-1230-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 11/27/2012] [Accepted: 12/03/2012] [Indexed: 11/28/2022]
Abstract
In the mammalian retina, light signals generated in photoreceptors are passed to bipolar and horizontal cells via synaptic contacts. In various pathological conditions, these second-order neurons extend neurites into the outer nuclear layer (ONL). However, the molecular events associated with this neurite outgrowth are not known. Here, we characterized the morphological synaptic changes in the CNGA3/CNGB1 double-knockout (A3B1) mouse, a model of retinitis pigmentosa. In these mice, horizontal cells looked normal until postnatal day (p) 11, but started growing neurites into the ONL 1 day later. At p28, the number of sprouting processes decreased, but the remaining sprouts developed synapse-like contacts at rod cell bodies, with an ultrastructural appearance reminiscent of ribbon synapses. Hence, neurite outgrowth and ectopic synaptogenesis in the A3B1 retina were precisely timed events starting at p12 and p28, respectively. We therefore performed microarray analysis of retinal gene expression in A3B1 and wild-type mice at those ages to evaluate the genomic response underlying these two events. This analysis identified 163 differentially regulated genes in the A3B1 retina related to neurite outgrowth or plasticity of synapses. The global changes in gene expression in the A3B1 retina were consistent with activation of signaling pathways related to Tp53, Smad, and Stat3. Moreover, key molecules of these signaling pathways could be localized at or in close proximity to outgrowing neurites. We therefore propose that Tp53, Smad, and Stat3 signaling pathways contribute to the synaptic plasticity in the A3B1 retina.
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Affiliation(s)
- Stylianos Michalakis
- Center for Integrated Protein Science Munich CiPSM and Department of Pharmacy – Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr 7, 81377 Munich, Germany
| | - Karin Schäferhoff
- Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Isabella Spiwoks-Becker
- Institute for Microscopic Anatomy and Neurobiology, University Medicine Mainz, Mainz, Germany
| | - Nawal Zabouri
- Neuroanatomy, Max-Planck-Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt, Germany
| | - Susanne Koch
- Center for Integrated Protein Science Munich CiPSM and Department of Pharmacy – Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr 7, 81377 Munich, Germany
| | - Fred Koch
- Center for Integrated Protein Science Munich CiPSM and Department of Pharmacy – Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr 7, 81377 Munich, Germany
| | - Michael Bonin
- Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich CiPSM and Department of Pharmacy – Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr 7, 81377 Munich, Germany
| | - Silke Haverkamp
- Neuroanatomy, Max-Planck-Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt, Germany
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89
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Hanke W, Mamasuew K, Biel M, Yang RB, Fleischer J. Odorant-evoked electrical responses in Grueneberg ganglion neurons rely on cGMP-associated signaling proteins. Neurosci Lett 2013; 539:38-42. [PMID: 23384572 DOI: 10.1016/j.neulet.2013.01.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 01/04/2013] [Accepted: 01/21/2013] [Indexed: 10/27/2022]
Abstract
The Grueneberg ganglion (GG) in the anterior nasal region of mice is considered as an olfactory compartment since its neurons were recently observed to be activated by chemical stimuli, in particular by the odorant 2,3-dimethylpyrazine (2,3-DMP). However, it is unclear whether the GG indeed serves an olfactory function since these findings are solely based on the expression of the activity-dependent gene c-Fos. Consequently, it is yet uncertain whether chemical compounds, such as given odorants, elicit electrical responses in GG neurons which are required to convey the chemosensory information to the brain. Therefore, in the present study, electrical recording experiments on tissue sections through the anterior nasal region of mice were conducted which revealed that 2,3-DMP induces electrical signals in the GG. These responses were restricted to sites harboring GG neurons, indicating that 2,3-DMP elicits an electrical signal only in these but not in other cells of the anterior nasal region. 2,3-DMP-sensitive GG neurons express signaling proteins associated with the second messenger substance cyclic guanosine monophosphate (cGMP); most notably the cyclic nucleotide-gated ion channel CNGA3 and the transmembrane guanylyl cyclase GC-G. Using mice deficient for CNGA3 or GC-G demonstrated that the 2,3-DMP-evoked electrical signals in the GG of these knockout mice were substantially lower than in the GG of wildtype conspecifics, indicating that cGMP signaling plays a crucial role for odorant-induced electrical responses in the GG.
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Affiliation(s)
- Wolfgang Hanke
- Institute of Physiology, University of Hohenheim, Stuttgart, Germany
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90
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Abstract
Cyclic guanosine 3'-5'-monophosphate (cGMP) plays a key role in the physiological process of light detection in photoreceptor cells of the retina. However, there is also growing evidence that cGMP may be critically involved in some pathophysiological processes of the retina since degenerating photoreceptors in mouse models of retinitis pigmentosa and achromatopsia accumulate high levels of cGMP. Here, we describe methods that allow the detection, subcellular localization, and quantification of cGMP in the retina and propose that cGMP accumulation can be used as a biomarker for photoreceptor degeneration.
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91
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Thomas MG, Gottlob I. Optical Coherence Tomography Studies Provides New Insights into Diagnosis and Prognosis of Infantile Nystagmus: A Review. Strabismus 2012; 20:175-80. [DOI: 10.3109/09273972.2012.735336] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Mervyn G. Thomas
- Ophthalmology Group, School of Medicine, University of Leicester,
Leicester, UK
| | - Irene Gottlob
- Ophthalmology Group, School of Medicine, University of Leicester,
Leicester, UK
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92
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Abstract
Calcium mediates various neuronal functions. The complexity of neuronal Ca²⁺ signaling is well exemplified by retinal cone photoreceptors, which, with their distinct compartmentalization, offer unique possibilities for studying the diversity of Ca²⁺ functions in a single cell. Measuring subcellular Ca²⁺ signals in cones under physiological conditions is not only fundamental for understanding cone function, it also bears important insights into pathophysiological processes governing retinal neurodegeneration. However, due to the proximity of light-sensitive outer segments to other cellular compartments, optical measurements of light-evoked Ca²⁺ responses in cones are challenging. We addressed this problem by generating a transgenic mouse (HR2.1:TN-XL) in which both short- and middle-wavelength-sensitive cones selectively express the genetically encoded ratiometric Ca²⁺ biosensor TN-XL. We show that HR2.1:TN-XL allows recording of light-evoked Ca²⁺ responses using two-photon imaging in individual cone photoreceptor terminals and to probe phototransduction and its diverse regulatory mechanisms with pharmacology at subcellular resolution. To further test this system, we asked whether the classical, nitric oxide (NO)-soluble guanylyl-cyclase (sGC)-cGMP pathway could modulate Ca²⁺ in cone terminals. Surprisingly, NO reduced Ca²⁺ resting levels in mouse cones, without evidence for direct sGC involvement. In conclusion, HR2.1:TN-XL mice offer unprecedented opportunities to elucidate light-driven Ca²⁺ dynamics and their (dys)regulation in cone photoreceptors.
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93
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Pang JJ, Lei L, Dai X, Shi W, Liu X, Dinculescu A, McDowell JH. AAV-mediated gene therapy in mouse models of recessive retinal degeneration. Curr Mol Med 2012; 12:316-30. [PMID: 22300136 DOI: 10.2174/156652412799218877] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 08/23/2011] [Accepted: 10/25/2011] [Indexed: 02/01/2023]
Abstract
In recent years, more and more mutant genes that cause retinal diseases have been detected. At the same time, many naturally occurring mouse models of retinal degeneration have also been found, which show similar changes to human retinal diseases. These, together with improved viral vector quality allow more and more traditionally incurable inherited retinal disorders to become potential candidates for gene therapy. Currently, the most common vehicle to deliver the therapeutic gene into target retinal cells is the adenoassociated viral vector (AAV). Following delivery to the immuno-privileged subretinal space, AAV-vectors can efficiently target both retinal pigment epithelium and photoreceptor cells, the origin of most retinal degenerations. This review focuses on the AAV-based gene therapy in mouse models of recessive retinal degenerations, especially those in which delivery of the correct copy of the wild-type gene has led to significant beneficial effects on visual function, as determined by morphological, biochemical, electroretinographic and behavioral analysis. The past studies in animal models and ongoing successful LCA2 clinical trials, predict a bright future for AAV gene replacement treatment for inherited recessive retinal diseases.
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Affiliation(s)
- J-J Pang
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, China.
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94
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Gene therapy restores missing cone-mediated vision in the CNGA3-/- mouse model of achromatopsia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 723:183-9. [PMID: 22183332 DOI: 10.1007/978-1-4614-0631-0_25] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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95
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AAV-mediated cone rescue in a naturally occurring mouse model of CNGA3-achromatopsia. PLoS One 2012; 7:e35250. [PMID: 22509403 PMCID: PMC3324465 DOI: 10.1371/journal.pone.0035250] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 03/12/2012] [Indexed: 12/22/2022] Open
Abstract
Achromatopsia is a rare autosomal recessive disorder which shows color blindness, severely impaired visual acuity, and extreme sensitivity to bright light. Mutations in the alpha subunits of the cone cyclic nucleotide-gated channels (CNGA3) are responsible for about 1/4 of achromatopsia in the U.S. and Europe. Here, we test whether gene replacement therapy using an AAV5 vector could restore cone-mediated function and arrest cone degeneration in the cpfl5 mouse, a naturally occurring mouse model of achromatopsia with a CNGA3 mutation. We show that gene therapy leads to significant rescue of cone-mediated ERGs, normal visual acuities and contrast sensitivities. Normal expression and outer segment localization of both M- and S-opsins were maintained in treated retinas. The therapeutic effect of treatment lasted for at least 5 months post-injection. This study is the first demonstration of substantial, relatively long-term restoration of cone-mediated light responsiveness and visual behavior in a naturally occurring mouse model of CNGA3 achromatopsia. The results provide the foundation for development of an AAV5-based gene therapy trial for human CNGA3 achromatopsia.
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96
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Thapa A, Morris L, Xu J, Ma H, Michalakis S, Biel M, Ding XQ. Endoplasmic reticulum stress-associated cone photoreceptor degeneration in cyclic nucleotide-gated channel deficiency. J Biol Chem 2012; 287:18018-29. [PMID: 22493484 DOI: 10.1074/jbc.m112.342220] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclic nucleotide-gated (CNG) channels play a pivotal role in phototransduction. Mutations in the cone CNG channel subunits CNGA3 and CNGB3 account for >70% of all known cases of achromatopsia. Cones degenerate in achromatopsia patients and in CNGA3(-/-) and CNGB3(-/-) mice. This work investigates the molecular basis of cone degeneration in CNG channel deficiency. As cones comprise only 2-3% of the total photoreceptor population in the wild-type mouse retina, we generated mouse lines with CNG channel deficiency on a cone-dominant background, i.e. CNGA3(-/-)/Nrl(-/-) and CNGB3(-/-)/Nrl(-/-) mice. The retinal phenotype and potential cell death pathways were examined by functional, biochemical, and immunohistochemical approaches. CNGA3(-/-)/Nrl(-/-) and CNGB3(-/-)/Nrl(-/-) mice showed impaired cone function, opsin mislocalization, and cone degeneration similar to that in the single knock-out mice. The endoplasmic reticulum stress marker proteins, including Grp78/Bip, phospho-eIF2α, phospho-IP(3)R, and CCAAT/enhancer-binding protein homologous protein, were elevated significantly in CNGA3(-/-)/Nrl(-/-) and CNGB3(-/-)/Nrl(-/-) retinas, compared with the age-matched (postnatal 30 days) Nrl(-/-) controls. Along with these, up-regulation of the cysteine protease calpains and cleavage of caspase-12 and caspase-7 were found in the channel-deficient retinas, suggesting an endoplasmic reticulum stress-associated apoptosis. In addition, we observed a nuclear translocation of apoptosis-inducing factor (AIF) and endonuclease G in CNGA3(-/-)/Nrl(-/-) and CNGB3(-/-)/Nrl(-/-) retinas, implying a mitochondrial insult in the endoplasmic reticulum stress-activated cell death process. Taken together, our findings suggest a crucial role of endoplasmic reticulum stress in cone degeneration associated with CNG channel deficiency.
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Affiliation(s)
- Arjun Thapa
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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97
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Xu J, Morris LM, Michalakis S, Biel M, Fliesler SJ, Sherry DM, Ding XQ. CNGA3 deficiency affects cone synaptic terminal structure and function and leads to secondary rod dysfunction and degeneration. Invest Ophthalmol Vis Sci 2012; 53:1117-29. [PMID: 22247469 DOI: 10.1167/iovs.11-8168] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To investigate rod function and survival after cone dysfunction and degeneration in a mouse model of cone cyclic nucleotide-gated (CNG) channel deficiency. METHODS Rod function and survival in mice with cone CNG channel subunit CNGA3 deficiency (CNGA3-/- mice) were evaluated by electroretinographic (ERG), morphometric, and Western blot analyses. The arrangement, integrity, and ultrastructure of photoreceptor terminals were investigated by immunohistochemistry and electron microscopy. RESULTS The authors found loss of cone function and cone death accompanied by impairment of rods and rod-driven signaling in CNGA3-/- mice. Scotopic ERG b-wave amplitudes were reduced by 15% at 1 month, 30% at 6 months, and 40% at 9 months and older, while scotopic a-wave amplitudes were decreased by 20% at 9 months, compared with ERGs of age-matched wild-type mice. Outer nuclear layer thickness in CNGA3-/- retina was reduced by 15% at 12 months compared with age-matched wild-type controls. This was accompanied by a 30%-40% reduction in expression of rod-specific proteins, including rhodopsin, rod transducin α-subunit, and glutamic acid-rich protein (GARP). Cone terminals in the CNGA3-/- retina showed a progressive loss of neurochemical and ultrastructural integrity. Abnormalities were observed as early as 1 month. Disorganized rod terminal ultrastructure was noted by 12 months. CONCLUSIONS These findings demonstrate secondary rod impairment and degeneration after cone degeneration in mice with cone CNG channel deficiency. Loss of cone phototransduction accompanies the compromised integrity of cone terminals. With time, rod synaptic structure, function, and viability also become compromised.
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Affiliation(s)
- Jianhua Xu
- Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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98
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Tanimoto N, Sothilingam V, Seeliger MW. Functional phenotyping of mouse models with ERG. Methods Mol Biol 2012; 935:69-78. [PMID: 23150360 DOI: 10.1007/978-1-62703-080-9_4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In many situations it is important to be able to assess the degree of retinal function, e.g., for the characterization of mouse models with unknown retinal involvement, when studying degenerative processes, for the analysis of visual signal processing, and during the follow-up of therapeutic interventions. Full-field electroretinography (ERG), yielding a sum response of event-related transient electrical activity of the entire retina to light stimulation, is widely applied in human as well as experimental functional diagnostics. ERG examinations normally include initial dark-adapted (scotopic) measurements that enable rod-driven activity to be studied, followed by light-adapted (photopic) recordings to obtain information about cone system contributions. The results allow the correlation of acute or long-term disease-related changes or their alleviation by therapy with morphological data, in order to obtain a comprehensive understanding of the underlying processes and mechanisms.
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Affiliation(s)
- Naoyuki Tanimoto
- Division of Ocular Neurodegeneration, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany.
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99
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Mujoo K, Krumenacker JS, Murad F. Nitric oxide-cyclic GMP signaling in stem cell differentiation. Free Radic Biol Med 2011; 51:2150-7. [PMID: 22019632 PMCID: PMC3232180 DOI: 10.1016/j.freeradbiomed.2011.09.037] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 09/27/2011] [Accepted: 09/29/2011] [Indexed: 12/15/2022]
Abstract
The nitric oxide-cyclic GMP (NO-cGMP) pathway mediates important physiological functions associated with various integrative body systems including the cardiovascular and nervous systems. Furthermore, NO regulates cell growth, survival, apoptosis, proliferation, and differentiation at the cellular level. To understand the significance of the NO-cGMP pathway in development and differentiation, studies have been conducted both in developing embryos and in stem cells. Manipulation of the NO-cGMP pathway, by employing activators and inhibitors as pharmacological probes, and genetic manipulation of NO signaling components have implicated the involvement of this pathway in the regulation of stem cell differentiation. This review focuses on some of the work pertaining to the role of NO-cGMP in the differentiation of stem cells into cells of various lineages, particularly into myocardial cells, and in stem cell-based therapy.
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Affiliation(s)
- Kalpana Mujoo
- Brown Foundation Institute of Molecular Medicine, Texas Therapeutics Institute, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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Wen R, Tao W, Li Y, Sieving PA. CNTF and retina. Prog Retin Eye Res 2011; 31:136-51. [PMID: 22182585 DOI: 10.1016/j.preteyeres.2011.11.005] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Revised: 10/29/2011] [Accepted: 11/17/2011] [Indexed: 11/15/2022]
Abstract
Ciliary neurotrophic factor (CNTF) is one of the most studied neurotrophic factors for neuroprotection of the retina. A large body of evidence demonstrates that CNTF promotes rod photoreceptor survival in almost all animal models. Recent studies indicate that CNTF also promotes cone photoreceptor survival and cone outer segment regeneration in the degenerating retina and improves cone function in dogs with congenital achromotopsia. In addition, CNTF is a neuroprotective factor and an axogenesis factor for retinal ganglion cells (RGCs). This review focuses on the effects of exogenous CNTF on photoreceptors and RGCs in the mammalian retina and the potential clinical application of CNTF for retinal degenerative diseases.
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Affiliation(s)
- Rong Wen
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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