1
|
Wilmet B, Michiels C, Zhang J, Callebert J, Sahel JA, Picaud S, Audo I, Zeitz C. Loss of ON-Pathway Function in Mice Lacking Lrit3 Decreases Recovery From Lens-Induced Myopia. Invest Ophthalmol Vis Sci 2024; 65:18. [PMID: 39250117 PMCID: PMC11385651 DOI: 10.1167/iovs.65.11.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2024] Open
Abstract
Purpose To determine whether the Lrit3-/- mouse model of complete congenital stationary night blindness with an ON-pathway defect harbors myopic features and whether the genetic defect influences the recovery from lens-induced myopia. Methods Retinal levels of dopamine (DA) and 3,4 dihydroxyphenylacetic acid (DOPAC) from adult isolated Lrit3-/- retinas were quantified using ultra performance liquid chromatography after light adaptation. Natural refractive development of Lrit3-/- mice was measured from three weeks to nine weeks of age using an infrared photorefractometer. Susceptibility to myopia induction was assessed using a lens-induced myopia protocol with -25 D lenses placed in front of the right eye of the animals for three weeks; the mean interocular shift was measured with an infrared photorefractometer after two and three weeks of goggling and after one and two weeks after removal of goggles. Results Compared to wild-type littermates (Lrit3+/+), both DA and DOPAC were drastically reduced in Lrit3-/- retinas. Natural refractive development was normal but Lrit3-/- mice showed a higher myopic shift and a lower ability to recover from induced myopia. Conclusions Our data consolidate the link between ON pathway defect altered dopaminergic signaling and myopia. We document for the first time the role of ON pathway on the recovery from myopia induction.
Collapse
Affiliation(s)
- Baptiste Wilmet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Jingyi Zhang
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Jacques Callebert
- Service of Biochemistry and Molecular Biology, INSERM U942, Hospital Lariboisière, Paris, France
| | - José Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburg, PA, United States
| | - Serge Picaud
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| |
Collapse
|
2
|
Hölzel MB, Kamermans W, Winkelman BHJ, Howlett MHC, De Zeeuw CI, Kamermans M. A common cause for nystagmus in different congenital stationary night blindness mouse models. J Physiol 2023; 601:5317-5340. [PMID: 37864560 DOI: 10.1113/jp284965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 09/22/2023] [Indexed: 10/23/2023] Open
Abstract
In Nyxnob mice, a model for congenital nystagmus associated with congenital stationary night blindness (CSNB), synchronous oscillating retinal ganglion cells (RGCs) lead to oscillatory eye movements, i.e. nystagmus. Given the specific expression of mGluR6 and Cav 1.4 in the photoreceptor to bipolar cell synapses, as well as their clinical association with CSNB, we hypothesize that Grm6nob3 and Cav 1.4-KO mutants show, like the Nyxnob mouse, oscillations in both their RGC activity and eye movements. Using multi-electrode array recordings of RGCs and measurements of the eye movements, we demonstrate that Grm6nob3 and Cav 1.4-KO mice also show oscillations of their RGCs as well as a nystagmus. Interestingly, the preferred frequencies of RGC activity as well as the eye movement oscillations of the Grm6nob3 , Cav 1.4-KO and Nyxnob mice differ among mutants, but the neuronal activity and eye movement behaviour within a strain remain aligned in the same frequency domain. Model simulations indicate that mutations affecting the photoreceptor-bipolar cell synapse can form a common cause of the nystagmus of CSNB by driving oscillations in RGCs via AII amacrine cells. KEY POINTS: In Nyxnob mice, a model for congenital nystagmus associated with congenital stationary night blindness (CSNB), their oscillatory eye movements (i.e. nystagmus) are caused by synchronous oscillating retinal ganglion cells. Here we show that the same mechanism applies for two other CSNB mouse models - Grm6nob3 and Cav 1.4-KO mice. We propose that the retinal ganglion cell oscillations originate in the AII amacrine cells. Model simulations show that by only changing the input to ON-bipolar cells, all phenotypical differences between the various genetic mouse models can be reproduced.
Collapse
Affiliation(s)
- Maj-Britt Hölzel
- Netherlands Institute for Neuroscience Amsterdam, Amsterdam, the Netherlands
| | - Wouter Kamermans
- Netherlands Institute for Neuroscience Amsterdam, Amsterdam, the Netherlands
| | - Beerend H J Winkelman
- Netherlands Institute for Neuroscience Amsterdam, Amsterdam, the Netherlands
- Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands
| | - Marcus H C Howlett
- Netherlands Institute for Neuroscience Amsterdam, Amsterdam, the Netherlands
| | - Chris I De Zeeuw
- Netherlands Institute for Neuroscience Amsterdam, Amsterdam, the Netherlands
- Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands
| | - Maarten Kamermans
- Netherlands Institute for Neuroscience Amsterdam, Amsterdam, the Netherlands
- Department of Biomedical Physics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| |
Collapse
|
3
|
Kamermans M, Winkelman BHJ, Hölzel MB, Howlett MHC, Kamermans W, Simonsz HJ, de Zeeuw CI. A retinal origin of nystagmus-a perspective. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1186280. [PMID: 38983059 PMCID: PMC11182158 DOI: 10.3389/fopht.2023.1186280] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 05/15/2023] [Indexed: 07/11/2024]
Abstract
Congenital nystagmus is a condition where the eyes of patients oscillate, mostly horizontally, with a frequency of between 2 and 10 Hz. Historically, nystagmus is believed to be caused by a maladaptation of the oculomotor system and is thus considered a disease of the brain stem. However, we have recently shown that congenital nystagmus associated with congenital stationary night blindness is caused by synchronously oscillating retinal ganglion cells. In this perspective article, we discuss how some details of nystagmus can be accounted for by the retinal mechanism we propose.
Collapse
Affiliation(s)
- Maarten Kamermans
- Department of Retinal Signal Processing, Netherlands Institute for Neuroscience Amsterdam, Amsterdam, Netherlands
- Department of Biomedical Physics, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Beerend H. J. Winkelman
- Department of Cerebellum: Coordination & Cognition, Netherlands Institute for Neuroscience Amsterdam, Amsterdam, Netherlands
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
| | - M-B. Hölzel
- Department of Retinal Signal Processing, Netherlands Institute for Neuroscience Amsterdam, Amsterdam, Netherlands
| | - Marcus H. C. Howlett
- Department of Retinal Signal Processing, Netherlands Institute for Neuroscience Amsterdam, Amsterdam, Netherlands
| | - Wouter Kamermans
- Department of Retinal Signal Processing, Netherlands Institute for Neuroscience Amsterdam, Amsterdam, Netherlands
- Department of Cerebellum: Coordination & Cognition, Netherlands Institute for Neuroscience Amsterdam, Amsterdam, Netherlands
| | - H. J. Simonsz
- Department of Cerebellum: Coordination & Cognition, Netherlands Institute for Neuroscience Amsterdam, Amsterdam, Netherlands
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, Netherlands
| | - C. I. de Zeeuw
- Department of Cerebellum: Coordination & Cognition, Netherlands Institute for Neuroscience Amsterdam, Amsterdam, Netherlands
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
| |
Collapse
|
4
|
Townes-Anderson E, Halász É, Sugino I, Davidow AL, Frishman LJ, Fritzky L, Yousufzai FAK, Zarbin M. Injury to Cone Synapses by Retinal Detachment: Differences from Rod Synapses and Protection by ROCK Inhibition. Cells 2023; 12:1485. [PMID: 37296606 PMCID: PMC10253016 DOI: 10.3390/cells12111485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
Attachment of a detached retina does not always restore vision to pre-injury levels, even if the attachment is anatomically successful. The problem is due in part to long-term damage to photoreceptor synapses. Previously, we reported on damage to rod synapses and synaptic protection using a Rho kinase (ROCK) inhibitor (AR13503) after retinal detachment (RD). This report documents the effects of detachment, reattachment, and protection by ROCK inhibition on cone synapses. Conventional confocal and stimulated emission depletion (STED) microscopy were used for morphological assessment and electroretinograms for functional analysis of an adult pig model of RD. RDs were examined 2 and 4 h after injury or two days later when spontaneous reattachment had occurred. Cone pedicles respond differently than rod spherules. They lose their synaptic ribbons, reduce invaginations, and change their shape. ROCK inhibition protects against these structural abnormalities whether the inhibitor is applied immediately or 2 h after the RD. Functional restoration of the photopic b-wave, indicating cone-bipolar neurotransmission, is also improved with ROCK inhibition. Successful protection of both rod and cone synapses with AR13503 suggests this drug will (1) be a useful adjunct to subretinal administration of gene or stem cell therapies and (2) improve recovery of the injured retina when treatment is delayed.
Collapse
Affiliation(s)
- Ellen Townes-Anderson
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA;
| | - Éva Halász
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA;
| | - Ilene Sugino
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, 90 Bergen Street, Newark, NJ 07103, USA; (I.S.); (M.Z.)
| | - Amy L. Davidow
- Department of Biostatistics, New York University School of Global Public Health, 708 Broadway, New York, NY 10003, USA;
| | - Laura J. Frishman
- Department of Vision Sciences, College of Optometry, University of Houston, Martin Luther King Blvd, Houston, TX 77204, USA;
| | - Luke Fritzky
- Cellular Imaging and Histology Core, Rutgers New Jersey Medical School, 205 South Orange Avenue, Newark, NJ 07103, USA; (L.F.); (F.A.K.Y.)
| | - Fawad A. K. Yousufzai
- Cellular Imaging and Histology Core, Rutgers New Jersey Medical School, 205 South Orange Avenue, Newark, NJ 07103, USA; (L.F.); (F.A.K.Y.)
| | - Marco Zarbin
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, 90 Bergen Street, Newark, NJ 07103, USA; (I.S.); (M.Z.)
| |
Collapse
|
5
|
Wilmet B, Callebert J, Duvoisin R, Goulet R, Tourain C, Michiels C, Frederiksen H, Schaeffel F, Marre O, Sahel JA, Audo I, Picaud S, Zeitz C. Mice Lacking Gpr179 with Complete Congenital Stationary Night Blindness Are a Good Model for Myopia. Int J Mol Sci 2022; 24:ijms24010219. [PMID: 36613663 PMCID: PMC9820543 DOI: 10.3390/ijms24010219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/25/2022] Open
Abstract
Mutations in GPR179 are one of the most common causes of autosomal recessive complete congenital stationary night blindness (cCSNB). This retinal disease is characterized in patients by impaired dim and night vision, associated with other ocular symptoms, including high myopia. cCSNB is caused by a complete loss of signal transmission from photoreceptors to ON-bipolar cells. In this study, we hypothesized that the lack of Gpr179 and the subsequent impaired ON-pathway could lead to myopic features in a mouse model of cCSNB. Using ultra performance liquid chromatography, we show that adult Gpr179-/- mice have a significant decrease in both retinal dopamine and 3,4-dihydroxyphenylacetic acid, compared to Gpr179+/+ mice. This alteration of the dopaminergic system is thought to be correlated with an increased susceptibility to lens-induced myopia but does not affect the natural refractive development. Altogether, our data added a novel myopia model, which could be used to identify therapeutic interventions.
Collapse
Affiliation(s)
- Baptiste Wilmet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Correspondence: (B.W.); (C.Z.); Tel.: +33-1-53-46-25-26 (B.W.); +33-1-53-46-25-40 (C.Z.)
| | - Jacques Callebert
- Service of Biochemistry and Molecular Biology, INSERM U942, Hospital Lariboisière, AP-HP, 75010 Paris, France
| | - Robert Duvoisin
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ruben Goulet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - Christophe Tourain
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS UMR8250, Paris Descartes University, 75270 Paris, France
| | - Christelle Michiels
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - Helen Frederiksen
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - Frank Schaeffel
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4056 Basel, Switzerland
- Section of Neurobiology of the Eye, Ophthalmic Research Institute, University of Tuebingen, 72076 Tuebingen, Germany
- Zeiss Vision Lab, Ophthalmic Research Institute, University of Tuebingen, 72076 Tuebingen, Germany
| | - Olivier Marre
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - José Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, 75012 Paris, France
- Fondation Ophtalmologique Adolphe de Rothschild, 75019 Paris, France
- Académie des Sciences, Institut de France, 75006 Paris, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, 75012 Paris, France
| | - Serge Picaud
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France
- Correspondence: (B.W.); (C.Z.); Tel.: +33-1-53-46-25-26 (B.W.); +33-1-53-46-25-40 (C.Z.)
| |
Collapse
|
6
|
Comparing the RETeval® portable ERG device with more traditional tabletop ERG systems in normal subjects and selected retinopathies. Doc Ophthalmol 2022; 146:137-150. [PMID: 36273363 PMCID: PMC10082128 DOI: 10.1007/s10633-022-09903-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/28/2022] [Indexed: 11/03/2022]
Abstract
Abstract
Purpose
Our study aimed to determine if ISCEV standard-like ERGs recorded with the LKC RETeval® portable ERG unit compared to those obtained using the more traditional tabletop unit.
Methods
ERGs recorded from normal subjects and patients affected with retinal ON and OFF pathway anomalies were compared. Analysis included peak time and amplitude measurements as well as time–frequency domain analysis with the discrete wavelet transform of waveforms obtained with the two systems.
Results
Although both systems were similarly able to record reliable and highly reproducible ERG responses, there were major discrepancies in ERG responses between the portable and tabletop units, pointing toward a weaker stimulation of the retinal OFF pathway with the portable RETeval® unit.
Conclusion
The portable RETeval® unit appears to be able to record highly reproducible and diagnostically useful clinical ERGs, albeit with some significant differences in waveform composition compared to those obtained with more standard tabletop systems. Given the unknown origin of these waveform discrepancies, if left uncorrected, these differences could potentially lead to erroneous interpretation when used in the clinical context and/or compared to ERGs recorded using more traditional table top units. Clearly, more research is warranted before handheld devices, such as the RETeval®, can be homologated as a diagnostically sound ERG devices.
Collapse
|
7
|
Aung MH, Hogan K, Mazade RE, Park HN, Sidhu CS, Iuvone PM, Pardue MT. ON than OFF pathway disruption leads to greater deficits in visual function and retinal dopamine signaling. Exp Eye Res 2022; 220:109091. [PMID: 35487263 DOI: 10.1016/j.exer.2022.109091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/15/2022] [Accepted: 04/20/2022] [Indexed: 11/19/2022]
Abstract
The visual system uses ON and OFF pathways to signal luminance increments and decrements. Increasing evidence suggests that ON and OFF pathways have different signaling properties and serve specialized visual functions. However, it is still unclear the contribution of ON and OFF pathways to visual behavior. Therefore, we examined the effects on optomotor response and the retinal dopamine system in nob mice with ON pathway dysfunction and Vsx1-/- mice with partial OFF pathway dysfunction. Spatial frequency and contrast sensitivity thresholds were determined, and values were compared to age-matched wild-type controls. Retinas were collected immediately after visual testing to measure levels of dopamine and its metabolite, DOPAC. At 4 weeks of age, we found that nob mice had significantly reduced spatial frequency (19%) and contrast sensitivity (60%) thresholds compared to wild-type mice. Vsx1-/- mice also exhibited reductions in optomotor responses (3% in spatial frequency; 18% in contrast sensitivity) at 4 weeks, although these changes were significantly smaller than those found in nob mice. Furthermore, nob mice had significantly lower DOPAC levels (53%) and dopamine turnover (41%) compared to controls while Vsx1-/- mice displayed a transient increase in DOPAC levels at 4 weeks of age (55%). Our results show that dysfunction of ON pathways leads to reductions in contrast sensitivity, spatial frequency threshold, and retinal dopamine and DOPAC levels whereas partial loss of the OFF pathway has minimal effect. We conclude that ON pathways play a critical role in visual reflexes and retinal dopamine signaling, highlighting a potential association for future investigations.
Collapse
Affiliation(s)
- Moe H Aung
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Health Care System, 1670 Clairmont Rd, Decatur, GA, 30033, USA; Neuroscience Program, Emory University School of Medicine, 1365 Clifton Rd NE, Atlanta, GA, 30322, USA; Department of Ophthalmology, Dell Medical School, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Kelleigh Hogan
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Health Care System, 1670 Clairmont Rd, Decatur, GA, 30033, USA; Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Dr, Atlanta, GA, 30332, USA
| | - Reece E Mazade
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Health Care System, 1670 Clairmont Rd, Decatur, GA, 30033, USA; Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Dr, Atlanta, GA, 30332, USA
| | - Han Na Park
- Neuroscience Program, Emory University School of Medicine, 1365 Clifton Rd NE, Atlanta, GA, 30322, USA; Department of Ophthalmology, Emory University School of Medicine, 1365 Clifton Road NE, Atlanta, GA, 0322, USA
| | - Curran S Sidhu
- Department of Ophthalmology, Emory University School of Medicine, 1365 Clifton Road NE, Atlanta, GA, 0322, USA
| | - P Michael Iuvone
- Neuroscience Program, Emory University School of Medicine, 1365 Clifton Rd NE, Atlanta, GA, 30322, USA; Department of Ophthalmology, Emory University School of Medicine, 1365 Clifton Road NE, Atlanta, GA, 0322, USA
| | - Machelle T Pardue
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Health Care System, 1670 Clairmont Rd, Decatur, GA, 30033, USA; Neuroscience Program, Emory University School of Medicine, 1365 Clifton Rd NE, Atlanta, GA, 30322, USA; Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Dr, Atlanta, GA, 30332, USA; Department of Ophthalmology, Emory University School of Medicine, 1365 Clifton Road NE, Atlanta, GA, 0322, USA.
| |
Collapse
|
8
|
Receptive Field Sizes of Nyxnob Mouse Retinal Ganglion Cells. Int J Mol Sci 2022; 23:ijms23063202. [PMID: 35328623 PMCID: PMC8951180 DOI: 10.3390/ijms23063202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/14/2022] [Accepted: 03/15/2022] [Indexed: 02/04/2023] Open
Abstract
Patients with congenital nystagmus, involuntary eye movements, often have a reduced visual acuity. Some of these patients have a retinal-specific mutation in the protein nyctalopin, which is also present in the Nyxnob mouse. In these mice, retinal ganglion cells (RGCs) have oscillatory activity, which leads to expanded axonal projections towards the dLGN and consequently to a desegregation of retinal projections to the brain. In this study, we investigate whether the receptive fields of Nyxnob RGCs have also expanded by measuring the size of their receptive fields using MEA recordings. Contrary to our expectation, relative to wild-type (WT) mice we found receptive field sizes in the Nyxnob retina had not increased but instead had decreased for green-light preferring RGCs. Additionally, we also found the receptive fields of UV-light preferring RGCs are larger than green-light preferring RGCs in both WT and Nyxnob mice.
Collapse
|
9
|
Agosto MA, Adeosun AAR, Kumar N, Wensel TG. The mGluR6 ligand-binding domain, but not the C-terminal domain, is required for synaptic localization in retinal ON-bipolar cells. J Biol Chem 2021; 297:101418. [PMID: 34793838 PMCID: PMC8671642 DOI: 10.1016/j.jbc.2021.101418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/03/2021] [Accepted: 11/08/2021] [Indexed: 11/26/2022] Open
Abstract
Signals from retinal photoreceptors are processed in two parallel channels—the ON channel responds to light increments, while the OFF channel responds to light decrements. The ON pathway is mediated by ON type bipolar cells (BCs), which receive glutamatergic synaptic input from photoreceptors via a G-protein-coupled receptor signaling cascade. The metabotropic glutamate receptor mGluR6 is located at the dendritic tips of all ON-BCs and is required for synaptic transmission. Thus, it is critically important for delivery of information from photoreceptors into the ON pathway. In addition to detecting glutamate, mGluR6 participates in interactions with other postsynaptic proteins, as well as trans-synaptic interactions with presynaptic ELFN proteins. Mechanisms of mGluR6 synaptic targeting and functional interaction with other synaptic proteins are unknown. Here, we show that multiple regions in the mGluR6 ligand-binding domain are necessary for both synaptic localization in BCs and ELFN1 binding in vitro. However, these regions were not required for plasma membrane localization in heterologous cells, indicating that secretory trafficking and synaptic localization are controlled by different mechanisms. In contrast, the mGluR6 C-terminus was dispensable for synaptic localization. In mGluR6 null mice, localization of the postsynaptic channel protein TRPM1 was compromised. Introducing WT mGluR6 rescued TRPM1 localization, while a C-terminal deletion mutant had significantly reduced rescue ability. We propose a model in which trans-synaptic ELFN1 binding is necessary for mGluR6 postsynaptic localization, whereas the C-terminus has a role in mediating TRPM1 trafficking. These findings reveal different sequence determinants of the multifunctional roles of mGluR6 in ON-BCs.
Collapse
Affiliation(s)
- Melina A Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston TX, USA.
| | - Abiodun Adefola R Adeosun
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston TX, USA; Pharmacology and Chemical Biology Graduate Program, Baylor College of Medicine, Houston TX, USA
| | - Nitin Kumar
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston TX, USA
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston TX, USA; Pharmacology and Chemical Biology Graduate Program, Baylor College of Medicine, Houston TX, USA
| |
Collapse
|
10
|
Small Leucine-Rich Proteoglycans (SLRPs) in the Retina. Int J Mol Sci 2021; 22:ijms22147293. [PMID: 34298915 PMCID: PMC8305803 DOI: 10.3390/ijms22147293] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 01/17/2023] Open
Abstract
Retinal diseases such as age-related macular degeneration (AMD), retinopathy of prematurity (ROP), and diabetic retinopathy (DR) are the leading causes of visual impairment worldwide. There is a critical need to understand the structural and cellular components that play a vital role in the pathophysiology of retinal diseases. One potential component is the family of structural proteins called small leucine-rich proteoglycans (SLRPs). SLRPs are crucial in many fundamental biological processes involved in the maintenance of retinal homeostasis. They are present within the extracellular matrix (ECM) of connective and vascular tissues and contribute to tissue organization and modulation of cell growth. They play a vital role in cell–matrix interactions in many upstream signaling pathways involved in fibrillogenesis and angiogenesis. In this comprehensive review, we describe the expression patterns and function of SLRPs in the retina, including Biglycan and Decorin from class I; Fibromodulin, Lumican, and a Proline/arginine-rich end leucine-rich repeat protein (PRELP) from class II; Opticin and Osteoglycin/Mimecan from class III; and Chondroadherin (CHAD), Tsukushi and Nyctalopin from class IV.
Collapse
|
11
|
Lukasiewcz PD, Bligard GW, DeBrecht JD. EAAT5 Glutamate Transporter-Mediated Inhibition in the Vertebrate Retina. Front Cell Neurosci 2021; 15:662859. [PMID: 34025361 PMCID: PMC8134652 DOI: 10.3389/fncel.2021.662859] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/19/2021] [Indexed: 12/29/2022] Open
Abstract
Glutamate transporters typically remove glutamate from the synaptic cleft. In addition, all glutamate transporters have a chloride channel, which is opened upon glutamate binding to the transporter. There are five types of glutamate transporter (EAATs 1–5, excitatory amino acid transporters), which have distinct chloride conductances. Some EAATs that have low chloride conductances, remove glutamate from the synaptic cleft most effectively (e.g., EAAT1). By contrast, EAATs that have high chloride conductances, remove glutamate less effectively (e.g., EAAT5). We have studied EAAT5 in the retina. In the retina, light activates a chloride current, mediated by the glutamate activation of EAAT5. EAAT5 is not a significant contributor to lateral inhibition in the retina. Instead, it is the main source of autoinhibition to rod bipolar cells (RBCs). EAAT5-mediated inhibition has a substantial effect on synaptic transmission from RBCs to downstream retinal neurons.
Collapse
Affiliation(s)
- Peter D Lukasiewcz
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, United States.,Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - Gregory W Bligard
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - James D DeBrecht
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| |
Collapse
|
12
|
Matsushima N, Miyashita H, Kretsinger RH. Sequence features, structure, ligand interaction, and diseases in small leucine rich repeat proteoglycans. J Cell Commun Signal 2021; 15:519-531. [PMID: 33860400 DOI: 10.1007/s12079-021-00616-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 03/25/2021] [Indexed: 12/26/2022] Open
Abstract
Small leucine rich repeat proteoglycans (SLRPs) are a group of active components of the extracellular matrix in all tissues. SLRPs bind to collagens and regulate collagen fibril growth and fibril organization. SLRPs also interact with various cytokines and extracellular compounds, which lead to various biological functions such cell adhesion and signaling, proliferation, and differentiation. Mutations in SLRP genes are associated with human diseases. Now crystal structures of five SLRPs are available. We describe some features of amino acid sequence and structures of SLRPs. We also review ligand interactions and then discuss the interaction surfaces. Furthermore, we map mutations associated with human diseases and discuss possible effects on structures by the mutations.
Collapse
Affiliation(s)
- Norio Matsushima
- Division of Bioinformatics, Institute of Tandem Repeats, Noboribetsu, 059-0464, Japan.
- Center for Medical Education, Sapporo Medical University, Sapporo, 060-8556, Japan.
| | - Hiroki Miyashita
- Division of Bioinformatics, Institute of Tandem Repeats, Noboribetsu, 059-0464, Japan
- Hokubu Rinsho Co., Ltd, Sapporo, 060⎼0061, Japan
| | - Robert H Kretsinger
- Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
| |
Collapse
|
13
|
Hayashi T, Murakami Y, Mizobuchi K, Koyanagi Y, Sonoda KH, Nakano T. Complete congenital stationary night blindness associated with a novel NYX variant (p.Asn216Lys) in middle-aged and older adult patients. Ophthalmic Genet 2021; 42:412-419. [PMID: 33769208 DOI: 10.1080/13816810.2021.1904422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Complete congenital stationary night blindness (CSNB) is a retinal disorder thought to be non-progressive. The purpose of this study was to characterize the clinical and genetic findings of middle-aged and older adult patients with X-linked complete CSNB. METHODS Three male CSNB patients (aged 62, 72, and 51 years) and one unaffected female carrier in a Japanese family were included in this study. Whole-exome sequencing (WES) was performed to determine the disease-causing variants. Co-segregation was confirmed in the family members. We performed a comprehensive ophthalmic examination on each patient. RESULTS In the 62-year-old patient, a novel hemizygous variant (c.648 C > A; p.Asn216Lys) of the NYX gene was identified by WES analysis. The other two patients carried the variant hemizygously, and the unaffected carrier harbored the variant heterozygously. The clinical and electroretinography (ERG) findings were very similar among all three patients. Fundus images exhibited high myopic chorioretinal atrophy with long axial length. Ultra-wide field fundus autofluorescence images showed no retinal degenerative changes except for changes resulting from high myopia and previous retinal diseases. The ERG findings showed no response in rod ERG, electronegative configuration with preserved a-waves in standard/bright-flash ERG, and preserved responses in cone and 30-Hz flicker ERG, which were compared with age-matched controls with high myopia. CONCLUSIONS We identified a novel missense NYX variant in a Japanese family with complete CSNB. Our clinical findings indicated that photoreceptor mediated ERG responses are well preserved even in middle-aged and older adult patients.
Collapse
Affiliation(s)
- Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan.,Department of Ophthalmology, Katsushika Medical Center, The Jikei University School of Medicine, Tokyo, Japan
| | - Yusuke Murakami
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kei Mizobuchi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Yoshito Koyanagi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Koh-Hei Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tadashi Nakano
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| |
Collapse
|
14
|
Agosto MA, Wensel TG. LRRTM4 is a member of the transsynaptic complex between rod photoreceptors and bipolar cells. J Comp Neurol 2020; 529:221-233. [PMID: 32390181 DOI: 10.1002/cne.24944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/09/2020] [Accepted: 05/01/2020] [Indexed: 12/22/2022]
Abstract
Leucine rich repeat transmembrane (LRRTM) proteins are synaptic adhesion molecules with roles in synapse formation and signaling. LRRTM4 transcripts were previously shown to be enriched in rod bipolar cells (BCs), secondary neurons of the retina that form synapses with rod photoreceptors. Using two different antibodies, LRRTM4 was found to reside primarily at rod BC dendritic tips, where it colocalized with the transduction channel protein, TRPM1. LRRTM4 was not detected at dendritic tips of ON-cone BCs. Following somatic knockout of LRRTM4 in BCs by subretinal injection and electroporation of CRISPR/Cas9, LRRTM4 was abolished or reduced in the dendritic tips of transfected cells. Knockout cells had a normal complement of TRPM1 at their dendritic tips, while GPR179 accumulation was partially reduced. In experiments with heterologously expressed protein, the extracellular domain of LRRTM4 was found to engage in heparan-sulfate dependent binding with pikachurin. These results implicate LRRTM4 in the GPR179-pikachurin-dystroglycan transsynaptic complex at rod synapses.
Collapse
Affiliation(s)
- Melina A Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|
15
|
Furukawa T, Ueno A, Omori Y. Molecular mechanisms underlying selective synapse formation of vertebrate retinal photoreceptor cells. Cell Mol Life Sci 2020; 77:1251-1266. [PMID: 31586239 PMCID: PMC11105113 DOI: 10.1007/s00018-019-03324-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/21/2019] [Accepted: 09/25/2019] [Indexed: 11/29/2022]
Abstract
In vertebrate central nervous systems (CNSs), highly diverse neurons are selectively connected via synapses, which are essential for building an intricate neural network. The vertebrate retina is part of the CNS and is comprised of a distinct laminar organization, which serves as a good model system to study developmental synapse formation mechanisms. In the retina outer plexiform layer, rods and cones, two types of photoreceptor cells, elaborate selective synaptic contacts with ON- and/or OFF-bipolar cell terminals as well as with horizontal cell terminals. In the mouse retina, three photoreceptor subtypes and at least 15 bipolar subtypes exist. Previous and recent studies have significantly progressed our understanding of how selective synapse formation, between specific subtypes of photoreceptor and bipolar cells, is designed at the molecular level. In the ON pathway, photoreceptor-derived secreted and transmembrane proteins directly interact in trans with the GRM6 (mGluR6) complex, which is localized to ON-bipolar cell dendritic terminals, leading to selective synapse formation. Here, we review our current understanding of the key factors and mechanisms underlying selective synapse formation of photoreceptor cells with bipolar and horizontal cells in the retina. In addition, we describe how defects/mutations of the molecules involved in photoreceptor synapse formation are associated with human retinal diseases and visual disorders.
Collapse
Affiliation(s)
- Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Akiko Ueno
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshihiro Omori
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| |
Collapse
|
16
|
Kinoshita J, Hasan N, Bell BA, Peachey NS. Reduced expression of the nob8 gene does not normalize the distribution or function of mGluR6 in the mouse retina. Mol Vis 2019; 25:890-901. [PMID: 32025181 PMCID: PMC6982428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 12/30/2019] [Indexed: 11/21/2022] Open
Abstract
Purpose The Grm6nob8 mouse carries a missense mutation in the Grm6 gene (p.Met66Leu), and exhibits a reduced b-wave of the electroretinogram (ERG), abnormal localization of metabotropic glutamate receptor 6 (mGluR6) to the depolarizing bipolar cell (DBC) soma, and a reduced level of mGluR6 at the DBC dendritic tips. Although the underlying mechanism remains unknown, one possible explanation is that DBCs cannot efficiently traffic the mutant mGluR6. In that scenario, reducing the total amount of mutant mGluR6 protein might normalize localization, and thus, improve the ERG phenotype as well. The second purpose of this study was to determine whether the abnormal cellular distribution of mutant mGluR6 in Grm6nob8 retinas might induce late onset DBC degeneration. Methods We crossed Grm6nob8 animals with Grm6nob3 mice, which carry a null mutation in Grm6, to generate Grm6nob3/nob8 compound heterozygotes. We used western blotting to measure the total mGluR6 content, and immunohistochemistry to document mGluR6 localization within DBCs. In addition, we examined outer retinal function with ERG and retinal architecture in vivo with spectral domain optical coherence tomography (SD-OCT). Results The retinal content of mGluR6 was reduced in the retinas of the Grm6nob3/nob8 compound heterozygotes compared to the Grm6nob8 homozygotes. The cellular distribution of mGluR6 in the Grm6nob3/nob8 compound heterozygotes matched that of the Grm6nob8 homozygotes, with extensive expression throughout the DBC cell body and limited expression at the DBC dendritic tips. The dark-adapted ERG b-waves of the Grm6nob3/nob8 mice were reduced in comparison to those of the Grm6nob8 homozygotes at postnatal day 21 and 28. The overall ERG waveforms obtained from 4- through 68-week old Grm6nob8 mice were in general agreement for dark- and light-adapted conditions. The maximum response and sensitivity of the dark-adapted ERG b-wave did not change statistically significantly with age. SD-OCT revealed the maintained laminar structure of the retina, including a clear inner nuclear layer (INL) at each age examined (from 11 to 57 weeks old), although the INL in the mice older than 39 weeks of age was somewhat thinner than that seen at 11 weeks. Conclusions Mislocalization of mutant mGluR6 is not normalized by reducing the total mGluR6. Mislocalized mutant mGluR6 does not trigger substantial loss of DBCs.
Collapse
Affiliation(s)
| | - Nazarul Hasan
- Department of Biochemistry & Molecular Genetics, University of Louisville, Louisville, KY
| | | | - Neal S. Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH
| |
Collapse
|
17
|
Ivanova ME, Zolnikova IV, Gorgisheli KV, Atarshchikov DS, Ghosh P, Barh D. Novel frameshift mutation in NYX gene in a Russian family with complete congenital stationary night blindness. Ophthalmic Genet 2019; 40:558-563. [PMID: 31826698 DOI: 10.1080/13816810.2019.1698617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Background: The complete form of X-linked congenital stationary night blindness (CSNB1A) is a very rare genetic disease caused by mutation in the NYX gene. CSNB1A-associated several mutations in the NYX gene have been reported earlier.Methods: In this case report, we have clinically diagnosed and genetically confirmed a novel mutation associated with CSNB1A in four members of a Russian family. Two male siblings from a family of four siblings (two girls, two boys) with non-progressive stable night blindness since early childhood and high myopia underwent - visual acuity test, perimetry, biomicroscopy, OCT, ophthalmoscopy, electroretinography, color vision Hue test, NGS based whole exome analysis and Sanger sequencing for clinical characterization and genetic confirmation of CSNB.Results: The members are clinically diagnosed and genetically confirmed with CSNB1A. All the patients had a novel frameshift mutation in the NYX gene (c.283delC, p.His95fs, NM_022567.2) that is found to segregate in X-linked mannerConclusions: This is probably the first case report with a novel mutation from Russia associated with CSNB1A.
Collapse
Affiliation(s)
| | | | | | | | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Debmalya Barh
- Oftalmic LLC, Moscow, Russia.,Center for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology (IIOAB), Purba Medinipur, India
| |
Collapse
|
18
|
Listik E, Azevedo Marques Gaschler J, Matias M, Neuppmann Feres MF, Toma L, Raphaelli Nahás-Scocate AC. Proteoglycans and dental biology: the first review. Carbohydr Polym 2019; 225:115199. [DOI: 10.1016/j.carbpol.2019.115199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 08/11/2019] [Accepted: 08/12/2019] [Indexed: 01/08/2023]
|
19
|
Akula JD, Ambrosio L, Howard FI, Hansen RM, Fulton AB. Extracting the ON and OFF contributions to the full-field photopic flash electroretinogram using summed growth curves. Exp Eye Res 2019; 189:107827. [PMID: 31600486 DOI: 10.1016/j.exer.2019.107827] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/27/2019] [Accepted: 10/02/2019] [Indexed: 10/25/2022]
Abstract
Under cone-mediated (photopic) conditions, an "instantaneous" flash of light, including both stimulus onset and offset, will simultaneously activate both "ON" and "OFF" bipolar cells, which either depolarize (ON) or hyperpolarize (OFF) in response and, respectively, produce positive-going and negative-going deflections in the electroretinogram (ERG). The stimulus-response (SR) relationship of the photopic ON response demonstrates logistic growth, like that manifested in the rod-mediated (scotopic) b-wave, which is driven by a single class of depolarizing bipolar cell. However, the photopic b-wave SR function is importantly shaped by OFF responses, leading to a "photopic hill." Furthermore, both on and off stimuli elicit activity in both ON and OFF bipolar cells. This has made it difficult to produce meaningful parameters for ready interpretation of the photopic b-wave SR relationship. Therefore, we evaluated whether the sum of sigmoidal SR functions, as descriptors of the depolarizing and hyperpolarizing components of the photopic flash ERG, could be used to elucidate and quantitate the mechanisms that produce the photopic hill. We used a novel fitting routine to optimize a sum of simple sigmoidal curves to SR data in five groups of subjects: Healthy adult, 10-week-old infant, congenital stationary night blindness (CSNB), X-linked juvenile retinoschisis (XJR), and preterm-born, both without and with a history of retinopathy of prematurity (ROP). Differences in ON and OFF amplitude, sensitivity, and implicit time among the groups were then compared using parameters extracted from these fits. We found that our modeling procedure enabled plausible derivations of ON and OFF pathway contributions to the ERG, and that the parameters produced appeared to have physiological relevance. In adult subjects, the ON and OFF amplitudes were similar in magnitude with respectively longer and shorter implicit times. Infant, CSNB, and XJR subjects showed significant ON pathway deficits. History of preterm-birth, without or with a diagnosis of ROP, did not much affect cone responses.
Collapse
Affiliation(s)
- James D Akula
- Ophthalmology, Boston Children's Hospital, Boston, MA, United States; Ophthalmology, Harvard Medical School, Boston, MA, United States.
| | - Lucia Ambrosio
- Ophthalmology, Boston Children's Hospital, Boston, MA, United States; Ophthalmology, Harvard Medical School, Boston, MA, United States
| | - Fiona I Howard
- Ophthalmology, Boston Children's Hospital, Boston, MA, United States; Psychology, Northeastern University, Boston, MA, United States
| | - Ronald M Hansen
- Ophthalmology, Boston Children's Hospital, Boston, MA, United States; Ophthalmology, Harvard Medical School, Boston, MA, United States
| | - Anne B Fulton
- Ophthalmology, Boston Children's Hospital, Boston, MA, United States; Ophthalmology, Harvard Medical School, Boston, MA, United States
| |
Collapse
|
20
|
Matsushima N, Takatsuka S, Miyashita H, Kretsinger RH. Leucine Rich Repeat Proteins: Sequences, Mutations, Structures and Diseases. Protein Pept Lett 2019; 26:108-131. [PMID: 30526451 DOI: 10.2174/0929866526666181208170027] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 12/18/2022]
Abstract
Mutations in the genes encoding Leucine Rich Repeat (LRR) containing proteins are associated with over sixty human diseases; these include high myopia, mitochondrial encephalomyopathy, and Crohn's disease. These mutations occur frequently within the LRR domains and within the regions that shield the hydrophobic core of the LRR domain. The amino acid sequences of fifty-five LRR proteins have been published. They include Nod-Like Receptors (NLRs) such as NLRP1, NLRP3, NLRP14, and Nod-2, Small Leucine Rich Repeat Proteoglycans (SLRPs) such as keratocan, lumican, fibromodulin, PRELP, biglycan, and nyctalopin, and F-box/LRR-repeat proteins such as FBXL2, FBXL4, and FBXL12. For example, 363 missense mutations have been identified. Replacement of arginine, proline, or cysteine by another amino acid, or the reverse, is frequently observed. The diverse effects of the mutations are discussed based on the known structures of LRR proteins. These mutations influence protein folding, aggregation, oligomerization, stability, protein-ligand interactions, disulfide bond formation, and glycosylation. Most of the mutations cause loss of function and a few, gain of function.
Collapse
Affiliation(s)
- Norio Matsushima
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan.,Institute of Tandem Repeats, Noboribetsu 059-0464, Japan
| | - Shintaro Takatsuka
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Hiroki Miyashita
- Institute of Tandem Repeats, Noboribetsu 059-0464, Japan.,Hokubu Rinsho Co., Ltd, Sapporo 060-0061, Japan
| | - Robert H Kretsinger
- Department of Biology, University of Virginia, Charlottesville, VA 22904, United States
| |
Collapse
|
21
|
Winkelman BHJ, Howlett MHC, Hölzel MB, Joling C, Fransen KH, Pangeni G, Kamermans S, Sakuta H, Noda M, Simonsz HJ, McCall MA, De Zeeuw CI, Kamermans M. Nystagmus in patients with congenital stationary night blindness (CSNB) originates from synchronously firing retinal ganglion cells. PLoS Biol 2019; 17:e3000174. [PMID: 31513577 PMCID: PMC6741852 DOI: 10.1371/journal.pbio.3000174] [Citation(s) in RCA: 13] [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: 02/12/2019] [Accepted: 08/12/2019] [Indexed: 11/19/2022] Open
Abstract
Congenital nystagmus, involuntary oscillating small eye movements, is commonly thought to originate from aberrant interactions between brainstem nuclei and foveal cortical pathways. Here, we investigated whether nystagmus associated with congenital stationary night blindness (CSNB) results from primary deficits in the retina. We found that CSNB patients as well as an animal model (nob mice), both of which lacked functional nyctalopin protein (NYX, nyx) in ON bipolar cells (BCs) at their synapse with photoreceptors, showed oscillating eye movements at a frequency of 4-7 Hz. nob ON direction-selective ganglion cells (DSGCs), which detect global motion and project to the accessory optic system (AOS), oscillated with the same frequency as their eyes. In the dark, individual ganglion cells (GCs) oscillated asynchronously, but their oscillations became synchronized by light stimulation. Likewise, both patient and nob mice oscillating eye movements were only present in the light when contrast was present. Retinal pharmacological and genetic manipulations that blocked nob GC oscillations also eliminated their oscillating eye movements, and retinal pharmacological manipulations that reduced the oscillation frequency of nob GCs also reduced the oscillation frequency of their eye movements. We conclude that, in nob mice, synchronized oscillations of retinal GCs, most likely the ON-DCGCs, cause nystagmus with properties similar to those associated with CSNB in humans. These results show that the nob mouse is the first animal model for a form of congenital nystagmus, paving the way for development of therapeutic strategies.
Collapse
Affiliation(s)
- Beerend H. J. Winkelman
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
- Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands
| | | | - Maj-Britt Hölzel
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Coen Joling
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Kathryn H. Fransen
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, United States of America
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, United States of America
| | - Gobinda Pangeni
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, United States of America
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, United States of America
| | | | - Hiraki Sakuta
- National Institute for Basic Biology, Okazaki, Japan
| | - Masaharu Noda
- National Institute for Basic Biology, Okazaki, Japan
| | - Huibert J. Simonsz
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
- Department of Ophthalmology, Erasmus MC, Rotterdam, the Netherlands
| | - Maureen A. McCall
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, United States of America
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, United States of America
| | - Chris I. De Zeeuw
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
- Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands
| | - Maarten Kamermans
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
- Department of Biomedical Physics, Academic Medical Center, University of Amsterdam, the Netherlands
- * E-mail:
| |
Collapse
|
22
|
Pang JJ, Yang Z, Jacoby RA, Wu SM. Cone synapses in mammalian retinal rod bipolar cells. J Comp Neurol 2018; 526:1896-1909. [PMID: 29667170 PMCID: PMC6031453 DOI: 10.1002/cne.24456] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 11/29/2017] [Accepted: 11/30/2017] [Indexed: 01/25/2023]
Abstract
Some mammalian rod bipolar cells (RBCs) can receive excitatory chemical synaptic inputs from both rods and cones (DBCR2 ), but anatomical evidence for mammalian cone-RBC contacts has been sparse. We examined anatomical cone-RBC contacts using neurobiotin (NB) to visualize individual mouse cones and standard immuno-markers to identify RBCs, cone pedicles and synapses in mouse and baboon retinas. Peanut agglutinin (PNA) stained the basal membrane of all cone pedicles, and mouse cones were positive for red/green (R/G)-opsin, whereas baboon cones were positive for calbindin D-28k. All synapses in the outer plexiform layer were labeled for synaptic vesicle protein 2 (SV2) and PSD (postsynaptic density)-95, and those that coincided with PNA resided closest to bipolar cell somas. Cone-RBC synaptic contacts were identified by: (a) RBC dendrites deeply invaginating into the center of cone pedicles (invaginating synapses), (b) RBC dendritic spines intruding into the surface of cone pedicles (superficial synapses), and (c) PKCα immunoreactivity coinciding with synaptic marker SV2, PSD-95, mGluR6, G protein beta 5 or PNA at cone pedicles. One RBC could form 0-1 invaginating and 1-3 superficial contacts with cones. 20.7% and 38.9% of mouse RBCs contacted cones in the peripheral and central retina (p < .05, n = 14 samples), respectively, while 34.4% (peripheral) and 48.5% (central) of cones contacted RBCs (p > .05). In baboon retinas (n = 4 samples), cone-RBC contacts involved 12.2% of RBCs (n = 416 cells) and 22.5% of cones (n = 225 cells). This suggests that rod and cone signals in the ON pathway are integrated in some RBCs before reaching AII amacrine cells.
Collapse
Affiliation(s)
- Ji-Jie Pang
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, 77030
| | - Zhuo Yang
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, 77030
| | - Roy A Jacoby
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, 77030
| | - Samuel M Wu
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, 77030
| |
Collapse
|
23
|
Abstract
The transient receptor potential channel TRPM1 is required for synaptic transmission between photoreceptors and the ON subtype of bipolar cells (ON-BPC), mediating depolarization in response to light. TRPM1 is present in the somas and postsynaptic dendritic tips of ON-BPCs. Monoclonal antibodies generated against full-length TRPM1 were found to have differential labeling patterns when used to immunostain the mouse retina, with some yielding reduced labeling of dendritic tips relative to the labeling of cell bodies. Epitope mapping revealed that those antibodies that poorly label the dendritic tips share a binding site (N2d) in the N-terminal arm near the transmembrane domain. A major splice variant of TRPM1 lacking exon 19 does not contain the N2d binding site, but quantitative immunoblotting revealed no enrichment of this variant in synaptsomes. One explanation of the differential labeling is masking of the N2d epitope by formation of a synapse-specific multiprotein complex. Identifying the binding partners that are specific for the fraction of TRPM1 present at the synapses is an ongoing challenge for understanding TRPM1 function.
Collapse
|
24
|
Abstract
Cacna1s encodes the α1S subunit (Cav1.1) of voltage-dependent calcium channels, and is required for normal skeletal and cardiac muscle function, where it couples with the ryanodine receptor to regulate muscle contraction. Recently CACNA1S was reported to be expressed on the tips of retinal depolarizing bipolar cells (DBCs) and colocalized with metabotropic glutamate receptor 6 (mGluR6), which is critical to DBC signal transduction. Further, in mGluR6 knockout mice, expression at this location is down regulated. We examined RNAseq data from mouse retina and found expression of a novel isoform of Cacna1s. To determine if CACNA1S was a functional component of the DBC signal transduction cascade, we performed immunohistochemistry to visualize its expression in several mouse lines that lack DBC function. Immunohistochemical staining with antibodies to CACNA1S show punctate labeling at the tips of DBCs in wild type (WT) retinas that are absent in Gpr179 nob5 mutant retinas and decreased in Grm6 -/- mouse retinas. CACNA1S and transient receptor potential cation channel, subfamily M, member 1 (TRPM1) staining also colocalized in WT retinas. Western blot analyses for CACNA1S of either retinal lysates or proteins after immunoprecipitation with the CACNA1S antibody failed to show the presence of bands expected for CACNA1S. Mass spectrometric analysis of CACNA1S immunoprecipitated proteins also failed to detect any peptides matching CACNA1S. Immunohistochemistry and western blotting after expression of GPR179 in HEK293T cells indicate that the CACNA1S antibody used here and in the retinal studies published to date, cross-reacts with GPR179. These data suggest caution should be exercised in conferring a role for CACNA1S in DBC signal transduction based solely on immunohistochemical staining.
Collapse
|
25
|
Martemyanov KA, Sampath AP. The Transduction Cascade in Retinal ON-Bipolar Cells: Signal Processing and Disease. Annu Rev Vis Sci 2017; 3:25-51. [PMID: 28715957 DOI: 10.1146/annurev-vision-102016-061338] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Our robust visual experience is based on the reliable transfer of information from our photoreceptor cells, the rods and cones, to higher brain centers. At the very first synapse of the visual system, information is split into two separate pathways, ON and OFF, which encode increments and decrements in light intensity, respectively. The importance of this segregation is borne out in the fact that receptive fields in higher visual centers maintain a separation between ON and OFF regions. In the past decade, the molecular mechanisms underlying the generation of ON signals have been identified, which are unique in their use of a G-protein signaling cascade. In this review, we consider advances in our understanding of G-protein signaling in ON-bipolar cell (BC) dendrites and how insights about signaling have emerged from visual deficits, mostly night blindness. Studies of G-protein signaling in ON-BCs reveal an intricate mechanism that permits the regulation of visual sensitivity over a wide dynamic range.
Collapse
Affiliation(s)
| | - Alapakkam P Sampath
- Jules Stein Eye Institute, University of California, Los Angeles, California 90095;
| |
Collapse
|
26
|
Neuillé M, Cao Y, Caplette R, Guerrero-Given D, Thomas C, Kamasawa N, Sahel JA, Hamel CP, Audo I, Picaud S, Martemyanov KA, Zeitz C. LRIT3 Differentially Affects Connectivity and Synaptic Transmission of Cones to ON- and OFF-Bipolar Cells. Invest Ophthalmol Vis Sci 2017; 58:1768-1778. [PMID: 28334377 PMCID: PMC5374884 DOI: 10.1167/iovs.16-20745] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose Mutations in LRIT3 lead to complete congenital stationary night blindness (cCSNB). Using a cCSNB mouse model lacking Lrit3 (nob6), we recently have shown that LRIT3 has a role in the correct localization of TRPM1 (transient receptor potential melastatin 1) to the dendritic tips of ON-bipolar cells (BCs), contacting both rod and cone photoreceptors. Furthermore, postsynaptic clustering of other mGluR6 cascade components is selectively eliminated at the dendritic tips of cone ON-BCs. The purpose of this study was to further define the role of LRIT3 in structural and functional organization of cone synapses. Methods Exhaustive electroretinogram analysis was performed in a patient with LRIT3 mutations. Multielectrode array recordings were performed at the level of retinal ganglion cells in nob6 mice. Targeting of GluR1 and GluR5 at the dendritic tips of OFF-BCs in nob6 retinas was assessed by immunostaining and confocal microscopy. The ultrastructure of photoreceptor synapses was evaluated by electron microscopy in nob6 mice. Results The patient with LRIT3 mutations had a selective ON-BC dysfunction with relatively preserved OFF-BC responses. In nob6 mice, complete lack of ON-pathway function with robust, yet altered signaling processing in OFF-pathways was detected. Consistent with these observations, molecules essential for the OFF-BC signaling were normally targeted to the synapse. Finally, synaptic contacts made by ON-BC but not OFF-BC neurons with the cone pedicles were disorganized without ultrastructural alterations in cone terminals, horizontal cell processes, or synaptic ribbons. Conclusions These results suggest that LRIT3 is likely involved in coordination of the transsynaptic communication between cones and ON-BCs during synapse formation and function.
Collapse
Affiliation(s)
- Marion Neuillé
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France
| | - Yan Cao
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida United States
| | - Romain Caplette
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France
| | | | - Connon Thomas
- Max Planck Florida Institute for Neuroscience, Jupiter, Florida United States
| | - Naomi Kamasawa
- Max Planck Florida Institute for Neuroscience, Jupiter, Florida United States
| | - José-Alain Sahel
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France 4CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France 5Institute of Ophthalmology, University College of London, London, United Kingdom 6Fondation Ophtalmologique Adolphe de Rothschild, Paris, France 8Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Christian P Hamel
- INSERM U583, Physiopathologie et thérapie des déficits sensoriels et moteurs, Institut des Neurosciences de Montpellier, Hôpital Saint-Eloi, Montpellier, France
| | - Isabelle Audo
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France 4CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France 5Institute of Ophthalmology, University College of London, London, United Kingdom
| | - Serge Picaud
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida United States
| | - Christina Zeitz
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France
| |
Collapse
|
27
|
Tu HY, Hsu CC, Chen YJ, Chen CK. Patch Clamp Recording of Starburst Amacrine Cells in a Flat-mount Preparation of Deafferentated Mouse Retina. J Vis Exp 2016:54608. [PMID: 27768050 PMCID: PMC5092195 DOI: 10.3791/54608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The mammalian retina is a layered tissue composed of multiple neuronal types. To understand how visual signals are processed within its intricate synaptic network, electrophysiological recordings are frequently used to study connections among individual neurons. We have optimized a flat-mount preparation for patch clamp recording of genetically marked neurons in both GCL (ganglion cell layer) and INL (inner nuclear layer) of mouse retinas. Recording INL neurons in flat-mounts is favored over slices because both vertical and lateral connections are preserved in the former configuration, allowing retinal circuits with large lateral components to be studied. We have used this procedure to compare responses of mirror-partnered neurons in retinas such as the cholinergic starburst amacrine cells (SACs).
Collapse
Affiliation(s)
- Hung-Ya Tu
- Department of Ophthalmology, Baylor College of Medicine
| | - Chih-Chun Hsu
- Department of Ophthalmology, Baylor College of Medicine; Department of Neuroscience, Baylor College of Medicine
| | - Yu-Jiun Chen
- Department of Ophthalmology, Baylor College of Medicine
| | - Ching-Kang Chen
- Department of Ophthalmology, Baylor College of Medicine; Department of Neuroscience, Baylor College of Medicine; Department of Biochemistry and Molecular Biology, Baylor College of Medicine;
| |
Collapse
|
28
|
Identification of a new mutant allele, Grm6(nob7), for complete congenital stationary night blindness. Vis Neurosci 2016; 32:E004. [PMID: 26241901 DOI: 10.1017/s0952523815000012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Electroretinogram (ERG) studies identified a new mouse line with a normal a-wave but lacking the b-wave component. The ERG phenotype of this new allele, nob7, matched closely that of mouse mutants for Grm6, Lrit3, Trpm1, and Nyx, which encode for proteins expressed in depolarizing bipolar cells (DBCs). To identify the underlying mutation, we first crossed nob7 mice with Grm6 nob3 mutants and measured the ERGs in offspring. All the offspring lacked the b-wave, indicating that nob7 is a new allele for Grm6: Grm6 nob7 . Sequence analyses of Grm6 nob7 cDNAs identified a 28 base pair insertion between exons 8 and 9, which would result in a frameshift mutation in the open reading frame that encodes the metabotropic glutamate receptor 6 (Grm6). Sequencing both the cDNA and genomic DNA from exon 8 and intron 8, respectively, from the Grm6 nob7 mouse revealed a G to A transition at the last position in exon 8. This mutation disrupts splicing and the normal exon 8 is extended by 28 base pairs, because splicing occurs 28 base pairs downstream at a cryptic splice donor. Consistent with the impact of the resulting frameshift mutation, there is a loss of mGluR6 protein (encoded by Grm6) from the dendritic tips of DBCs in the Grm6 nob7 retina. These results indicate that Grm6 nob7 is a new model of the complete form of congenital stationary night blindness, a human condition that has been linked to mutations of GRM6.
Collapse
|
29
|
Tanimoto N, Akula JD, Fulton AB, Weber BHF, Seeliger MW. Differentiation of murine models of “negative ERG” by single and repetitive light stimuli. Doc Ophthalmol 2016; 132:101-9. [DOI: 10.1007/s10633-016-9534-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/03/2016] [Indexed: 02/03/2023]
|
30
|
Abstract
The first synapses transmitting visual information contain an unusual organelle, the ribbon, which is involved in the transport and priming of vesicles to be released at the active zone. The ribbon is one of many design features that allow efficient refilling of the active zone, which in turn enables graded changes in membrane potential to be transmitted using a continuous mode of neurotransmitter release. The ribbon also plays a key role in supplying vesicles for rapid and transient bursts of release that signal fast changes, such as the onset of light. We increasingly understand how the physiological properties of ribbon synapses determine basic transformations of the visual signal and, in particular, how the process of refilling the active zone regulates the gain and adaptive properties of the retinal circuit. The molecular basis of ribbon function is, however, far from clear.
Collapse
Affiliation(s)
- Leon Lagnado
- School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom;
| | - Frank Schmitz
- Department of Neuroanatomy, Institute for Anatomy and Cell Biology, Medical School Saarland University, Homburg/Saar, Germany;
| |
Collapse
|
31
|
Soto F, Kerschensteiner D. Synaptic remodeling of neuronal circuits in early retinal degeneration. Front Cell Neurosci 2015; 9:395. [PMID: 26500497 PMCID: PMC4595653 DOI: 10.3389/fncel.2015.00395] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 09/22/2015] [Indexed: 11/27/2022] Open
Abstract
Photoreceptor degenerations are a major cause of blindness and among the most common forms of neurodegeneration in humans. Studies of mouse models revealed that synaptic dysfunction often precedes photoreceptor degeneration, and that abnormal synaptic input from photoreceptors to bipolar cells causes circuits in the inner retina to become hyperactive. Here, we provide a brief overview of frequently used mouse models of photoreceptor degenerations. We then discuss insights into circuit remodeling triggered by early synaptic dysfunction in the outer and hyperactivity in the inner retina. We discuss these insights in the context of other experimental manipulations of synaptic function and activity. Knowledge of the plasticity and early remodeling of retinal circuits will be critical for the design of successful vision rescue strategies.
Collapse
Affiliation(s)
- Florentina Soto
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine in St. Louis St. Louis, MO, USA
| | - Daniel Kerschensteiner
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine in St. Louis St. Louis, MO, USA ; Department of Anatomy and Neurobiology, Washington University School of Medicine in St. Louis St. Louis, MO, USA ; Department of Biomedical Engineering, Washington University School of Medicine in St. Louis St. Louis, MO, USA ; Hope Center for Neurological Disorders, Washington University School of Medicine in St. Louis St. Louis, MO, USA
| |
Collapse
|
32
|
A Naturally Occurring Canine Model of Autosomal Recessive Congenital Stationary Night Blindness. PLoS One 2015; 10:e0137072. [PMID: 26368928 PMCID: PMC4569341 DOI: 10.1371/journal.pone.0137072] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 08/12/2015] [Indexed: 11/20/2022] Open
Abstract
Congenital stationary night blindness (CSNB) is a non-progressive, clinically and genetically heterogeneous disease of impaired night vision. We report a naturally-occurring, stationary, autosomal recessive phenotype in beagle dogs with normal daylight vision but absent night vision. Affected dogs had normal retinas on clinical examination, but showed no detectable rod responses. They had “negative-type” mixed rod and cone responses in full-field ERGs. Their photopic long-flash ERGs had normal OFF-responses associated with severely reduced ON-responses. The phenotype is similar to the Schubert-Bornschein form of complete CSNB in humans. Homozygosity mapping ruled out most known CSNB candidates as well as CACNA2D4 and GNB3. Three remaining genes were excluded based on sequencing the open reading frame and intron-exon boundaries (RHO, NYX), causal to a different form of CSNB (RHO) or X-chromosome (NYX, CACNA1F) location. Among the genes expressed in the photoreceptors and their synaptic terminals, and mGluR6 cascade and modulators, reduced expression of GNAT1, CACNA2D4 and NYX was observed by qRT-PCR in both carrier (n = 2) and affected (n = 2) retinas whereas CACNA1F was down-regulated only in the affecteds. Retinal morphology revealed normal cellular layers and structure, and electron microscopy showed normal rod spherules and synaptic ribbons. No difference from normal was observed by immunohistochemistry (IHC) for antibodies labeling rods, cones and their presynaptic terminals. None of the retinas showed any sign of stress. Selected proteins of mGluR6 cascade and its modulators were examined by IHC and showed that PKCα weakly labeled the rod bipolar somata in the affected, but intensely labeled axonal terminals that appeared thickened and irregular. Dendritic terminals of ON-bipolar cells showed increased Goα labeling. Both PKCα and Goα labeled the more prominent bipolar dendrites that extended into the OPL in affected but not normal retinas. Interestingly, RGS11 showed no labeling in the affected retina. Our results indicate involvement of a yet unknown gene in this canine model of complete CSNB.
Collapse
|
33
|
Xiong WH, Pang JJ, Pennesi ME, Duvoisin RM, Wu SM, Morgans CW. The Effect of PKCα on the Light Response of Rod Bipolar Cells in the Mouse Retina. Invest Ophthalmol Vis Sci 2015; 56:4961-74. [PMID: 26230760 DOI: 10.1167/iovs.15-16622] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Protein kinase C α (PKCα) is abundantly expressed in rod bipolar cells (RBCs) in the retina, yet the physiological function of PKCα in these cells is not well understood. To elucidate the role of PKCα in visual processing in the eye, we examined the effect of genetic deletion of PKCα on the ERG and on RBC light responses in the mouse. METHODS Immunofluorescent labeling was performed on wild-type (WT), TRPM1 knockout, and PKCα knockout (PKC-KO) retina. Scotopic and photopic ERGs were recorded from WT and PKC-KO mice. Light responses of RBCs were measured using whole-cell recordings in retinal slices from WT and PKC-KO mice. RESULTS Protein kinase C alpha expression in RBCs is correlated with the activity state of the cell. Rod bipolar cells dendrites are a major site of PKCα phosphorylation. Electroretinogram recordings indicated that loss of PKCα affects the scotopic b-wave, including a larger peak amplitude, longer implicit time, and broader width of the b-wave. There were no differences in the ERG a- or c-wave between PKCα KO and WT mice, indicating no measurable effect of PKCα in photoreceptors or the RPE. The photopic ERG was unaffected consistent with the lack of detectable PKCα in cone bipolar cells. Whole-cell recordings from RBCs in PKC-KO retinal slices revealed that, compared with WT, RBC light responses in the PKC-KO retina are delayed and of longer duration. CONCLUSIONS Protein kinase C alpha plays an important modulatory role in RBCs, regulating both the peak amplitude and temporal properties of the RBC light response in the rod visual pathway.
Collapse
Affiliation(s)
- Wei-Hong Xiong
- Department of Physiology & Pharmacology Oregon Health & Science University, Portland, Oregon, United States
| | - Ji-Jie Pang
- Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, United States
| | - Mark E Pennesi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Robert M Duvoisin
- Department of Physiology & Pharmacology Oregon Health & Science University, Portland, Oregon, United States
| | - Samuel M Wu
- Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, United States
| | - Catherine W Morgans
- Department of Physiology & Pharmacology Oregon Health & Science University, Portland, Oregon, United States
| |
Collapse
|
34
|
Scalabrino ML, Boye SL, Fransen KMH, Noel JM, Dyka FM, Min SH, Ruan Q, De Leeuw CN, Simpson EM, Gregg RG, McCall MA, Peachey NS, Boye SE. Intravitreal delivery of a novel AAV vector targets ON bipolar cells and restores visual function in a mouse model of complete congenital stationary night blindness. Hum Mol Genet 2015; 24:6229-39. [PMID: 26310623 DOI: 10.1093/hmg/ddv341] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/17/2015] [Indexed: 11/13/2022] Open
Abstract
Adeno-associated virus (AAV) effectively targets therapeutic genes to photoreceptors, pigment epithelia, Müller glia and ganglion cells of the retina. To date, no one has shown the ability to correct, with gene replacement, an inherent defect in bipolar cells (BCs), the excitatory interneurons of the retina. Targeting BCs with gene replacement has been difficult primarily due to the relative inaccessibility of BCs to standard AAV vectors. This approach would be useful for restoration of vision in patients with complete congenital stationary night blindness (CSNB1), where signaling through the ON BCs is eliminated due to mutations in their G-protein-coupled cascade genes. For example, the majority of CSNB1 patients carry a mutation in nyctalopin (NYX), which encodes a protein essential for proper localization of the TRPM1 cation channel required for ON BC light-evoked depolarization. As a group, CSNB1 patients have a normal electroretinogram (ERG) a-wave, indicative of photoreceptor function, but lack a b-wave due to defects in ON BC signaling. Despite retinal dysfunction, the retinas of CSNB1 patients do not degenerate. The Nyx(nob) mouse model of CSNB1 faithfully mimics this phenotype. Here, we show that intravitreally injected, rationally designed AAV2(quadY-F+T-V) containing a novel 'Ple155' promoter drives either GFP or YFP_Nyx in postnatal Nyx(nob) mice. In treated Nyx(nob) retina, robust and targeted Nyx transgene expression in ON BCs partially restored the ERG b-wave and, at the cellular level, signaling in ON BCs. Our results support the potential for gene delivery to BCs and gene replacement therapy in human CSNB1.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Charles N De Leeuw
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada V5Z 4H4, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Elizabeth M Simpson
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada V5Z 4H4, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Ronald G Gregg
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY 40202, USA
| | - Maureen A McCall
- Department of Ophthalmology and Visual Sciences, Department of Anatomical Sciences and Neurobiology and
| | - Neal S Peachey
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Shannon E Boye
- Department of Ophthalmology and, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL 32610, USA,
| |
Collapse
|
35
|
Schneider FM, Mohr F, Behrendt M, Oberwinkler J. Properties and functions of TRPM1 channels in the dendritic tips of retinal ON-bipolar cells. Eur J Cell Biol 2015; 94:420-7. [PMID: 26111660 DOI: 10.1016/j.ejcb.2015.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
An increase in light intensity induces a depolarization in retinal ON-bipolar cells via a reduced glutamate release from presynaptic photoreceptor cells. The underlying transduction cascade in the dendritic tips of ON-bipolar cells involves mGluR6 glutamate receptors signaling to TRPM1 proteins that are an indispensable part of the transduction channel. Several other proteins are recognized to participate in the transduction machinery. Deficiency in many of these leads to congenital stationary night blindness, because rod bipolar cells, a subgroup of ON-bipolar cells, constitute the main route for sensory information under scotopic conditions. Here, we review the current knowledge about TRPM1 ion channels and how their activity is regulated within the postsynaptic compartment of ON-bipolar cells. The functional properties of TRPM1 channels in the dendritic compartment are not well understood as they differ substantially from those of recombinant TRPM1 channels. Critical evaluation of possible explanations of these discrepancies indicates that some key components of this transduction pathway might still not be known. The continued exploration of this pathway will yield further clinically useful insights.
Collapse
Affiliation(s)
- Franziska M Schneider
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany
| | - Florian Mohr
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany
| | - Marc Behrendt
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany
| | - Johannes Oberwinkler
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany.
| |
Collapse
|
36
|
Zhou L, Li T, Song X, Li Y, Li H, Dan H. NYX mutations in four families with high myopia with or without CSNB1. Mol Vis 2015; 21:213-23. [PMID: 25802485 PMCID: PMC4357032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 03/03/2015] [Indexed: 11/03/2022] Open
Abstract
PURPOSE Mutations in the NYX gene are known to cause complete congenital stationary night blindness (CSNB1), which is always accompanied by high myopia. In this study, we aimed to investigate the association between NYX mutations and high myopia with or without CSNB1. METHODS Four Chinese families having high myopia with or without CSNB1 and 96 normal controls were recruited. We searched for mutations in the NYX gene using Sanger sequencing. Further analyses of the detected variations in the available family members were performed, and the frequencies of the detected variations in 96 normal controls were determined to verify our deduction. The effect of each variation on the nyctalopin protein was predicted using online tools. RESULTS Four potential pathogenic variations in the NYX gene were found in four families with high myopia with or without CSNB1. Three of the four variants were novel (c.626G>C; c.121delG; c.335T>C). The previously identified variant, c.529_530delGCinsAT, was found in an isolated highly myopic patient and an affected brother, but the other affected brother did not carry the same variation. Further linkage analyses of this family showed a coinheritance of markers at MYP1. These four mutations were not identified in the 96 normal controls. CONCLUSIONS Our study expands the mutation spectrum of NYX for cases of high myopia with CSNB1; however, more evidence is needed to elucidate the pathogenic effects of NYX on isolated high myopia.
Collapse
Affiliation(s)
- Lin Zhou
- Department of Ophthalmology, Remin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China,Department of Ophthalmology, Central Hospital of Enshi Autonomous Prefecture, Enshi Clinical College of Wuhan University, Enshi, Hubei Province, People's Republic of China
| | - Tuo Li
- Department of Ophthalmology, Central Hospital of Enshi Autonomous Prefecture, Enshi Clinical College of Wuhan University, Enshi, Hubei Province, People's Republic of China
| | - Xiusheng Song
- Department of Ophthalmology, Central Hospital of Enshi Autonomous Prefecture, Enshi Clinical College of Wuhan University, Enshi, Hubei Province, People's Republic of China
| | - Yin Li
- Department of Ophthalmology, Remin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China,Department of Ophthalmology, Central Hospital of Enshi Autonomous Prefecture, Enshi Clinical College of Wuhan University, Enshi, Hubei Province, People's Republic of China
| | - Hongyan Li
- Department of Ophthalmology, Central Hospital of Enshi Autonomous Prefecture, Enshi Clinical College of Wuhan University, Enshi, Hubei Province, People's Republic of China
| | - Handong Dan
- Department of Ophthalmology, Central Hospital of Enshi Autonomous Prefecture, Enshi Clinical College of Wuhan University, Enshi, Hubei Province, People's Republic of China
| |
Collapse
|
37
|
Congenital stationary night blindness: An analysis and update of genotype–phenotype correlations and pathogenic mechanisms. Prog Retin Eye Res 2015; 45:58-110. [DOI: 10.1016/j.preteyeres.2014.09.001] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/25/2014] [Accepted: 09/30/2014] [Indexed: 01/18/2023]
|
38
|
Agosto MA, Zhang Z, He F, Anastassov IA, Wright SJ, McGehee J, Wensel TG. Oligomeric state of purified transient receptor potential melastatin-1 (TRPM1), a protein essential for dim light vision. J Biol Chem 2014; 289:27019-27033. [PMID: 25112866 PMCID: PMC4175340 DOI: 10.1074/jbc.m114.593780] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 08/03/2014] [Indexed: 11/06/2022] Open
Abstract
Transient receptor potential melastatin-1 (TRPM1) is essential for the light-induced depolarization of retinal ON bipolar cells. TRPM1 likely forms a multimeric channel complex, although almost nothing is known about the structure or subunit composition of channels formed by TRPM1 or any of its close relatives. Recombinant TRPM1 was robustly expressed in insect cells, but only a small fraction was localized to the plasma membrane. Similar intracellular localization was observed when TRPM1 was heterologously expressed in mammalian cells. TRPM1 was affinity-purified from Sf9 cells and complexed with amphipol, followed by detergent removal. In blue native gels and size exclusion chromatography, TRPM1 migrated with a mobility consistent with detergent- or amphipol-bound dimers. Cross-linking experiments were also consistent with a dimeric subunit stoichiometry, and cryoelectron microscopy and single particle analysis without symmetry imposition yielded a model with approximate 2-fold symmetrical features. Finally, electron microscopy of TRPM1-antibody complexes revealed a large particle that can accommodate TRPM1 and two antibody molecules. Taken together, these data indicate that purified TRPM1 is mostly dimeric. The three-dimensional structure of TRPM1 dimers is characterized by a small putative transmembrane domain and a larger domain with a hollow cavity. Blue native gels of solubilized mouse retina indicate that TRPM1 is present in two distinct complexes: one similar in size to the recombinant protein and one much larger. Because dimers are likely not functional ion channels, these results suggest that additional partner subunits participate in forming the transduction channel required for dim light vision and the ON pathway.
Collapse
Affiliation(s)
- Melina A Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Zhixian Zhang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Feng He
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Ivan A Anastassov
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Sara J Wright
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Jennifer McGehee
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.
| |
Collapse
|
39
|
Hoon M, Okawa H, Della Santina L, Wong ROL. Functional architecture of the retina: development and disease. Prog Retin Eye Res 2014; 42:44-84. [PMID: 24984227 DOI: 10.1016/j.preteyeres.2014.06.003] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/08/2014] [Accepted: 06/22/2014] [Indexed: 12/22/2022]
Abstract
Structure and function are highly correlated in the vertebrate retina, a sensory tissue that is organized into cell layers with microcircuits working in parallel and together to encode visual information. All vertebrate retinas share a fundamental plan, comprising five major neuronal cell classes with cell body distributions and connectivity arranged in stereotypic patterns. Conserved features in retinal design have enabled detailed analysis and comparisons of structure, connectivity and function across species. Each species, however, can adopt structural and/or functional retinal specializations, implementing variations to the basic design in order to satisfy unique requirements in visual function. Recent advances in molecular tools, imaging and electrophysiological approaches have greatly facilitated identification of the cellular and molecular mechanisms that establish the fundamental organization of the retina and the specializations of its microcircuits during development. Here, we review advances in our understanding of how these mechanisms act to shape structure and function at the single cell level, to coordinate the assembly of cell populations, and to define their specific circuitry. We also highlight how structure is rearranged and function is disrupted in disease, and discuss current approaches to re-establish the intricate functional architecture of the retina.
Collapse
Affiliation(s)
- Mrinalini Hoon
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Haruhisa Okawa
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Luca Della Santina
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA.
| |
Collapse
|
40
|
GPR179 is required for high sensitivity of the mGluR6 signaling cascade in depolarizing bipolar cells. J Neurosci 2014; 34:6334-43. [PMID: 24790204 DOI: 10.1523/jneurosci.4044-13.2014] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Parallel visual pathways are initiated at the first retinal synapse by signaling between the rod and cone photoreceptors and two general classes of bipolar cells. For normal function, ON or depolarizing bipolar cells (DBCs) require the G-protein-coupled receptor, mGluR6, an intact G-protein-coupled cascade and the transient receptor potential melastatin 1 (TRPM1) cation channel. In addition, another seven transmembrane protein, GPR179, is required for DBC function and recruits the regulators of G-protein signaling (RGS) proteins, RGS7 and RGS11, to the dendritic tips of the DBCs. Here we use the Gpr179(nob5) mouse, which lacks GPR179 and has a no b-wave electroretinogram (ERG) phenotype, to demonstrate that despite the absence of both GPR179 and RGS7/RGS11, a small dark-adapted ERG b-wave remains and can be enhanced with long duration flashes. Consistent with the ERG, the mGluR6-mediated gating of TRPM1 can be evoked pharmacologically in Gpr179(nob5) and RGS7(-/-)/RGS11(-/-) rod BCs if strong stimulation conditions are used. In contrast, direct gating of TRPM1 by capsaicin in RGS7(-/-)/RGS11(-/-) and WT rod BCs is similar, but severely compromised in Gpr179(nob5) rod BCs. Noise and standing current analyses indicate that the remaining channels in Gpr179(nob5) and RGS7(-/-)/RGS11(-/-) rod BCs have a very low open probability. We propose that GPR179 along with RGS7 and RGS11 controls the ability of the mGluR6 cascade to gate TRPM1. In addition to its role in localizing RGS7 and RGS11 to the dendritic tips, GPR179 via a direct interaction with the TRPM1 channel alters its ability to be gated directly by capsaicin.
Collapse
|
41
|
Garon ML, Dorfman AL, Racine J, Koenekoop RK, Little JM, Lachapelle P. Estimating ON and OFF contributions to the photopic hill: normative data and clinical applications. Doc Ophthalmol 2014; 129:9-16. [PMID: 24894580 DOI: 10.1007/s10633-014-9446-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 05/26/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND With progressively brighter stimuli, the amplitude of the b-wave of the human photopic electroretinogram (ERG) first increases to a maximal value (Vmax) and then decreases to finally reach a plateau, a phenomenon known as the photopic hill (PH). A mathematical model combining a Gaussian (G) and a logistic (L) growth function was previously proposed to fit this unusual luminance-response curve, where the G and L functions were suggested to represent, respectively, the OFF and ON retinal pathway contributions to the building of the PH. METHOD The PHs of patients presenting stationary diseases affecting specifically the ON (3 CSNB-1) or OFF (4 CPCPA) retinal pathways as well as patients affected with retinitis pigmentosa (14 RP) of different stages or etiology were analyzed using this mathematical model and compared to the PHs of a group of 28 normal subjects. RESULTS The PH of the CSNB-1 patients had a much larger contribution from the G function compared to normal subjects, whereas the opposite was observed for the CPCPA patients. On the other hand, analysis of data from RP patients revealed variable G-L contributions to the building of their PH. CONCLUSION In this study, we confirm the previous claim that the luminance-response function of the photopic ERG b-wave can be decomposed into a Gaussian function and a logistic growth function representing, respectively, the OFF and ON retinal pathways. Furthermore, our findings suggest that this mathematical decomposition could be useful to further segregate and potentially follow the progression of retinopathies such as RP.
Collapse
Affiliation(s)
- M-L Garon
- Department of Ophthalmology (D-164), McGill University - Montreal Children's Hospital Research Institute, 2300 Tupper Street, Montreal, QC, H3H 1P3, Canada
| | | | | | | | | | | |
Collapse
|
42
|
Malaichamy S, Sen P, Sachidanandam R, Arokiasamy T, Lancelot ME, Audo I, Zeitz C, Soumittra N. Molecular profiling of complete congenital stationary night blindness: a pilot study on an Indian cohort. Mol Vis 2014; 20:341-51. [PMID: 24715752 PMCID: PMC3962728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 03/18/2014] [Indexed: 10/27/2022] Open
Abstract
PURPOSE Congenital stationary night blindness (CSNB) is a non-progressive retinal disorder that shows genetic and clinical heterogeneity. CSNB is inherited as an autosomal recessive, autosomal dominant, or X-linked recessive trait and shows a good genotype-phenotype correlation. Clinically, CSNB is classified as the Riggs type and the Schubert-Bornschein type. The latter form is further sub-classified into complete and incomplete forms based on specific waveforms on the electroretinogram (ERG). There are no molecular genetic data for CSNB in the Indian population. Therefore, we present for the first time molecular profiling of eight families with complete CSNB (cCSNB). METHODS The index patients and their other affected family members were comprehensively evaluated for the phenotype, including complete ophthalmic evaluation, ERG, fundus autofluorescence, optical coherence tomography, and color vision test. The known gene defects for cCSNB, LRIT3, TRPM1, GRM6, GPR179, and NYX, were screened by PCR direct sequencing. Bioinformatic analyses were performed using SIFT and PolyPhen for the identified missense mutations. RESULTS All eight affected index patients and affected family members were identified as having cCSNB based on their ERG waveforms. Mutations in the TRPM1 gene were identified in six index patients. The two remaining index patients each carried a GPR179 and GRM6 mutation. Seven of the patients revealed homozygous mutations, while one patient showed a compound heterozygous mutation. Six of the eight mutations identified are novel. CONCLUSIONS This is the first report on molecular profiling of candidate genes in CSNB in an Indian cohort. As shown for other cohorts, TRPM1 seems to be a major gene defect in patients with cCSNB in India.
Collapse
Affiliation(s)
- Sivasankar Malaichamy
- SNONGC department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - Parveen Sen
- Department of Vitreo-Retinal Services, Medical Research Foundation, Chennai, India
| | | | - Tharigopala Arokiasamy
- SNONGC department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - Marie Elise Lancelot
- INSERM, U968, Paris, F-75012, France,CNRS, UMR_7210, Paris, F-75012, France,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, F-75012, France
| | - Isabelle Audo
- INSERM, U968, Paris, F-75012, France,CNRS, UMR_7210, Paris, F-75012, France,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, F-75012, France,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 503, Paris F-75012, France,UCL-Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Christina Zeitz
- INSERM, U968, Paris, F-75012, France,CNRS, UMR_7210, Paris, F-75012, France,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, F-75012, France
| | - Nagasamy Soumittra
- SNONGC department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| |
Collapse
|
43
|
Abstract
The b-wave is a major component of the electroretinogram that reflects the activity of depolarizing bipolar cells (DBCs). The b-wave is used diagnostically to identify patients with defects in DBC signaling or in transmission from photoreceptors to DBCs. In mouse models, an abnormal b-wave has been used to demonstrate a critical role of a particular protein in the release of glutamate from photoreceptor terminals, in establishing the structure of the photoreceptor-to-DBC synapse, in DBC signal transduction, and also in DBC development, survival, or metabolic support. The purpose of this review is to summarize these models and how they have advanced our understanding of outer retinal function.
Collapse
|
44
|
Abstract
The transient receptor potential (TRP) channels play a wide variety of essential roles in the sensory systems of various species, both invertebrates and vertebrates. The TRP channel was first identified as a molecule required for proper light response in Drosophila melanogaster. We and another group recently revealed that TRPM1, the founding member of the melanoma-related transient receptor potential (TRPM) subfamily, is required for the photoresponse in mouse retinal ON-bipolar cells. We further demonstrated that Trpm1 is a component of the transduction cation channel negatively regulated by the metabotropic glutamate receptor 6 (mGulR6) cascade in ON-bipolar cells through a reconstitution experiment using CHO cells expressing Trpm1, mGluR6, and Goα. Furthermore, human TRPM1 mutations are associated with congenital stationary night blindness (CSNB), whose patients lack rod function and suffer from night blindness starting in early childhood. In addition to the function of transduction cation channel, TRPM1 is one of the retinal autoantigens in some paraneoplastic retinopathy (PR) associated with retinal ON-bipolar cell dysfunction. In this chapter, we describe physiological functions of the TRPM1 channel and its underlying biochemical mechanisms in retinal ON-bipolar cells in association with CSNB and PR.
Collapse
Affiliation(s)
- Shoichi Irie
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | | |
Collapse
|
45
|
Klooster J, van Genderen MM, Yu M, Florijn RJ, Riemslag FCC, Bergen AAB, Gregg RG, Peachey NS, Kamermans M. Ultrastructural localization of GPR179 and the impact of mutant forms on retinal function in CSNB1 patients and a mouse model. Invest Ophthalmol Vis Sci 2013; 54:6973-81. [PMID: 24084093 DOI: 10.1167/iovs.13-12293] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Complete congenital stationary night blindness (CSNB1) is characterized by loss of night vision due to a defect in the retinal ON-bipolar cells (BCs). Mutations in GPR179, encoding the G-protein-coupled receptor 179, have been found in CSNB1 patients. In the mouse, GPR179 is localized to the tips of ON-BC dendrites. In this study we determined the ultrastructural localization of GPR179 in human retina and determined the functional consequences of mutations in GPR179 in patients and mice. METHODS The localization of GRP179 was analyzed in postmortem human retinas with immunohistochemistry. The functional consequences of the loss of GPR179 were analyzed with standard and 15-Hz flicker ERG protocols. RESULTS In the human retina, GPR179 is localized on the tips of ON-BC dendrites, which invaginate photoreceptors and terminate juxtaposed to the synaptic ribbon. The 15-Hz flicker ERG abnormalities found in patients with mutations in GPR179 more closely resemble those from patients with mutations in either TRPM1 or NYX than in GRM6. 15-Hz flicker ERG abnormalities of Gpr179(nob5) and Grm6(nob3) mice were comparable. CONCLUSIONS GRP179 is expressed on dendrites of ON-BCs, indicating that GRP179 is involved in the ON-BCs' signaling cascade. The similarities of 15-Hz flicker ERGs noted in GPR179 patients and NYX or TRPM1 patients suggest that the loss of GPR179 leads to the loss or closure of TRPM1 channels. The difference between the 15-Hz flicker ERGs of mice and humans indicates the presence of important species differences in the retinal activity that this signal represents.
Collapse
Affiliation(s)
- Jan Klooster
- Retinal Signal Processing, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Bijveld MMC, Florijn RJ, Bergen AAB, van den Born LI, Kamermans M, Prick L, Riemslag FCC, van Schooneveld MJ, Kappers AML, van Genderen MM. Genotype and phenotype of 101 dutch patients with congenital stationary night blindness. Ophthalmology 2013; 120:2072-81. [PMID: 23714322 DOI: 10.1016/j.ophtha.2013.03.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 02/25/2013] [Accepted: 03/01/2013] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE To investigate the relative frequency of the genetic causes of the Schubert-Bornschein type of congenital stationary night blindness (CSNB) and to determine the genotype-phenotype correlations in CSNB1 and CSNB2. DESIGN Clinic-based, longitudinal, multicenter study. PARTICIPANTS A total of 39 patients with CSNB1 from 29 families and 62 patients with CSNB2 from 43 families. METHODS Patients underwent full ophthalmologic and electrophysiologic examinations. On the basis of standard electroretinograms (ERGs), patients were diagnosed with CSNB1 or CSNB2. Molecular analysis was performed by direct Sanger sequencing of the entire coding regions in NYX, TRPM1, GRM6, and GPR179 in patients with CSNB1 and CACNA1F and CABP4 in patients with CSNB2. MAIN OUTCOME MEASURES Data included genetic cause of CSNB, refractive error, visual acuity, nystagmus, strabismus, night blindness, photophobia, color vision, dark adaptation (DA) curve, and standard ERGs. RESULTS A diagnosis of CSNB1 or CSNB2 was based on standard ERGs. The photopic ERG was the most specific criterion to distinguish between CSNB1 and CSNB2 because it showed a "square-wave" appearance in CSNB1 and a decreased b-wave in CSNB2. Mutations causing CSNB1 were found in NYX (20 patients, 13 families), TRPM1 (10 patients, 9 families), GRM6 (4 patients, 3 families), and GPR179 (2 patients, 1 family). Congenital stationary night blindness 2 was primarily caused by mutations in CACNA1F (55 patients, 37 families). Only 3 patients had causative mutations in CABP4 (2 families). Patients with CSNB1 mainly had rod-related problems, and patients with CSNB2 had rod- and cone-related problems. The visual acuity on average was better in CSNB1 (0.30 logarithm of the minimum angle of resolution [logMAR]) than in CSNB2 (0.52 logMAR). All patients with CSNB1 and only 54% of the patients with CSNB2 reported night blindness. The dark-adapted threshold was on average more elevated in CSNB1 (3.0 log) than in CSNB2 (1.8 log). The 3 patients with CABP4 had a relative low visual acuity, were hyperopic, had severe nonspecific color vision defects, and had only 1.0 log elevated DA threshold. CONCLUSIONS Congenital stationary night blindness 1, despite different causative mutations, shows 1 unique CSNB1 phenotype. Congenital stationary night blindness 2 caused by mutations in CABP4 merely shows cone-related problems and therefore appears to be distinct from CSNB2 caused by mutations in CACNA1F. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Collapse
Affiliation(s)
- Mieke M C Bijveld
- Bartiméus Institute for the Visually Impaired, Zeist, The Netherlands; MOVE Research Institute, Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Bijveld MMC, van Genderen MM, Hoeben FP, Katzin AA, van Nispen RMA, Riemslag FCC, Kappers AML. Assessment of night vision problems in patients with congenital stationary night blindness. PLoS One 2013; 8:e62927. [PMID: 23658786 PMCID: PMC3643903 DOI: 10.1371/journal.pone.0062927] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 03/27/2013] [Indexed: 12/03/2022] Open
Abstract
Congenital Stationary Night Blindness (CSNB) is a retinal disorder caused by a signal transmission defect between photoreceptors and bipolar cells. CSNB can be subdivided in CSNB2 (rod signal transmission reduced) and CSNB1 (rod signal transmission absent). The present study is the first in which night vision problems are assessed in CSNB patients in a systematic way, with the purpose of improving rehabilitation for these patients. We assessed the night vision problems of 13 CSNB2 patients and 9 CSNB1 patients by means of a questionnaire on low luminance situations. We furthermore investigated their dark adapted visual functions by the Goldmann Weekers dark adaptation curve, a dark adapted static visual field, and a two-dimensional version of the “Light Lab”. In the latter test, a digital image of a living room with objects was projected on a screen. While increasing the luminance of the image, we asked the patients to report on detection and recognition of objects. The questionnaire showed that the CSNB2 patients hardly experienced any night vision problems, while all CSNB1 patients experienced some problems although they generally did not describe them as severe. The three scotopic tests showed minimally to moderately decreased dark adapted visual functions in the CSNB2 patients, with differences between patients. In contrast, the dark adapted visual functions of the CSNB1 patients were more severely affected, but showed almost no differences between patients. The results from the “2D Light Lab” showed that all CSNB1 patients were blind at low intensities (equal to starlight), but quickly regained vision at higher intensities (full moonlight). Just above their dark adapted thresholds both CSNB1 and CSNB2 patients had normal visual fields. From the results we conclude that night vision problems in CSNB, in contrast to what the name suggests, are not conspicuous and generally not disabling.
Collapse
Affiliation(s)
- Mieke M C Bijveld
- Bartiméus Institute for the Visually Impaired, Zeist, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
48
|
Dhingra A, Vardi N. "mGlu Receptors in the Retina" - WIREs Membrane Transport and Signaling. WILEY INTERDISCIPLINARY REVIEWS. MEMBRANE TRANSPORT AND SIGNALING 2012; 1:641-653. [PMID: 24003403 PMCID: PMC3755759 DOI: 10.1002/wmts.43] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Glutamate, a key neurotransmitter in the vertebrate retina, acts via ionotropic and metabotropic receptors. Retina expresses mRNA for all metabotropic glutamate receptors and proteins for all but mGluR3. Every retinal cell class expresses one or more of these receptors. In general, these receptors are present presynaptically and serve to modulate synaptic transmission. While mGluRs on the photoreceptor terminal act as autoreceptors to titer glutamate levels, those on horizontal cell processes seem to shape the light response. Similarly, autoreceptors on bipolar axon terminals modulate glutamate release and the receptors on amacrine and ganglion cells modulate feedforward signals by modulating K+ or Ca2+ current to fine tune light responses. Since most of the mGluR sub-types are present in amacrine and ganglion cells that belong to many cell types, the pathways downstream of mGluRs are highly diverse with primarily modulatory effects. An exception to most mGluRs which have modulatory function is mGluR6 because it plays a key role in the feedforward transmission from photoreceptors to ON bipolar cells and is also required for the correct localization of the synaptic proteins in the dendritic tips. In humans, mutations in the gene encoding mGluR6 cause autosomal recessive night blindness. In addition, mGluRs appear to play a trophic role in development and after retinal damage, suggesting potential future therapeutic implications.
Collapse
|
49
|
Peachey NS, Pearring JN, Bojang P, Hirschtritt ME, Sturgill-Short G, Ray TA, Furukawa T, Koike C, Goldberg AFX, Shen Y, McCall MA, Nawy S, Nishina PM, Gregg RG. Depolarizing bipolar cell dysfunction due to a Trpm1 point mutation. J Neurophysiol 2012; 108:2442-51. [PMID: 22896717 DOI: 10.1152/jn.00137.2012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mutations in TRPM1 are found in humans with an autosomal recessive form of complete congenital stationary night blindness (cCSNB). The Trpm1(-/-) mouse has been an important animal model for this condition. Here we report a new mouse mutant, tvrm27, identified in a chemical mutagenesis screen. Genetic mapping of the no b-wave electroretinogram (ERG) phenotype of tvrm27 localized the mutation to a chromosomal region that included Trpm1. Complementation testing with Trpm1(-/-) mice confirmed a mutation in Trpm1. Sequencing identified a nucleotide change in exon 23, converting a highly conserved alanine within the pore domain to threonine (p.A1068T). Consistent with prior studies of Trpm1(-/-) mice, no anatomical changes were noted in the Trpm1(tvrm27/tvrm27) retina. The Trpm1(tvrm27/tvrm27) phenotype is distinguished from that of Trpm1(-/-) by the retention of TRPM1 expression on the dendritic tips of depolarizing bipolar cells (DBCs). While ERG b-wave amplitudes of Trpm1(+/-) heterozygotes are comparable to wild type, those of Trpm1(+/tvrm27) mice are reduced by 32%. A similar reduction in the response of Trpm1(+/tvrm27) DBCs to LY341495 or capsaicin is evident in whole cell recordings. These data indicate that the p.A1068T mutant TRPM1 acts as a dominant negative with respect to TRPM1 channel function. Furthermore, these data indicate that the number of functional TRPM1 channels at the DBC dendritic tips is a key factor in defining DBC response amplitude. The Trpm1(tvrm27/tvrm27) mutant will be useful for elucidating the role of TRPM1 in DBC signal transduction, for determining how Trpm1 mutations impact central visual processing, and for evaluating experimental therapies for cCSNB.
Collapse
Affiliation(s)
- Neal S Peachey
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Peachey NS, Sturgill-Short GM. Response properties of slow PIII in the Large (vls) mutant. Doc Ophthalmol 2012; 125:203-9. [PMID: 22865473 DOI: 10.1007/s10633-012-9347-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 07/23/2012] [Indexed: 11/24/2022]
Abstract
PURPOSE Mouse mutants for proteins expressed in the dystrophin-glycoprotein complex at the photoreceptor terminal have electroretinogram (ERG) b-waves with a delayed onset and time course. The b-wave is defined by the sum of PII generated by depolarizing bipolar cells and slow PIII generated by Müller glial cells. In this study, we evaluated the hypothesis that the abnormalities observed in one of these mutants, Large (vls) , are caused by abnormal response properties of slow PIII. METHODS To isolate slow PIII, we crossed the Large (vls) mutant to a mouse line (Gpr179 (nob5) ) that lacks the ERG b-wave but maintains normal photoreceptor function and in which retinal degeneration does not occur. ERGs were recorded to strobe flash stimuli after overnight dark adaptation. RESULTS In comparison with control responses, the a-wave and slow PIII had comparable waveforms but were reduced in amplitude in Large (vls) mice. The magnitude of this reduction was comparable for these components, and across stimulus luminance. There was no stimulus condition where the amplitude of slow PIII was larger than control. CONCLUSIONS The data obtained are inconsistent with the idea that the b-wave abnormalities noted in Large (vls) mutant mice are caused by abnormal response properties of slow PIII.
Collapse
Affiliation(s)
- Neal S Peachey
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA. ,Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA. .,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
| | - Gwen M Sturgill-Short
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH, 44106, USA
| |
Collapse
|