1
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Miller ML, Pindwarawala M, Agosto MA. Complex N-glycosylation of mGluR6 is required for trans-synaptic interaction with ELFN adhesion proteins. J Biol Chem 2024; 300:107119. [PMID: 38428819 PMCID: PMC10973816 DOI: 10.1016/j.jbc.2024.107119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/30/2024] [Accepted: 02/16/2024] [Indexed: 03/03/2024] Open
Abstract
Synaptic transmission from retinal photoreceptors to downstream ON-type bipolar cells (BCs) depends on the postsynaptic metabotropic glutamate receptor mGluR6, located at the BC dendritic tips. Glutamate binding to mGluR6 initiates G-protein signaling that ultimately leads to BC depolarization in response to light. The mGluR6 receptor also engages in trans-synaptic interactions with presynaptic ELFN adhesion proteins. The roles of post-translational modifications in mGluR6 trafficking and function are unknown. Treatment with glycosidase enzymes PNGase F and Endo H demonstrated that both endogenous and heterologously expressed mGluR6 contain complex N-glycosylation acquired in the Golgi. Pull-down experiments with ELFN1 and ELFN2 extracellular domains revealed that these proteins interact exclusively with the complex glycosylated form of mGluR6. Mutation of the four predicted N-glycosylation sites, either singly or in combination, revealed that all four sites are glycosylated. Single mutations partially reduced, but did not abolish, surface expression in heterologous cells, while triple mutants had little or no surface expression, indicating that no single glycosylation site is necessary or sufficient for plasma membrane trafficking. Mutation at N445 severely impaired both ELFN1 and ELFN2 binding. All single mutants exhibited dendritic tip enrichment in rod BCs, as did the triple mutant with N445 as the sole N-glycosylation site, demonstrating that glycosylation at N445 is sufficient but not necessary for dendritic tip localization. The quadruple mutant was completely mislocalized. These results reveal a key role for complex N-glycosylation in regulating mGluR6 trafficking and ELFN binding, and by extension, function of the photoreceptor synapses.
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Affiliation(s)
- Michael L Miller
- Faculty of Science, Medical Sciences Program, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Mustansir Pindwarawala
- Faculty of Science, Medical Sciences Program, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Melina A Agosto
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada.
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2
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Boff JM, Shrestha AP, Madireddy S, Viswaprakash N, Della Santina L, Vaithianathan T. The Interplay between Neurotransmitters and Calcium Dynamics in Retinal Synapses during Development, Health, and Disease. Int J Mol Sci 2024; 25:2226. [PMID: 38396913 PMCID: PMC10889697 DOI: 10.3390/ijms25042226] [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: 01/11/2024] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
The intricate functionality of the vertebrate retina relies on the interplay between neurotransmitter activity and calcium (Ca2+) dynamics, offering important insights into developmental processes, physiological functioning, and disease progression. Neurotransmitters orchestrate cellular processes to shape the behavior of the retina under diverse circumstances. Despite research to elucidate the roles of individual neurotransmitters in the visual system, there remains a gap in our understanding of the holistic integration of their interplay with Ca2+ dynamics in the broader context of neuronal development, health, and disease. To address this gap, the present review explores the mechanisms used by the neurotransmitters glutamate, gamma-aminobutyric acid (GABA), glycine, dopamine, and acetylcholine (ACh) and their interplay with Ca2+ dynamics. This conceptual outline is intended to inform and guide future research, underpinning novel therapeutic avenues for retinal-associated disorders.
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Affiliation(s)
- Johane M Boff
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Abhishek P Shrestha
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Saivikram Madireddy
- College of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Nilmini Viswaprakash
- Department of Medical Education, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | | | - Thirumalini Vaithianathan
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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3
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Chen W, Zhong W, Yu L, Lin X, Xie J, Liu Z. A Drosophila Model Reveals the Potential Role for mtt in Retinal Disease. Int J Mol Sci 2024; 25:899. [PMID: 38255972 PMCID: PMC10815649 DOI: 10.3390/ijms25020899] [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: 12/12/2023] [Revised: 01/03/2024] [Accepted: 01/06/2024] [Indexed: 01/24/2024] Open
Abstract
Congenital stationary night blindness (CSNB) is a genetically heterogeneous inherited retinal disorder, caused by over 300 mutations in 17 different genes. While there are numerous fly models available for simulating ocular diseases, most are focused on mimicking retinitis pigmentosa (RP), with animal models specifically addressing CSNB limited to mammals. Here, we present a CSNB fly model associated with the mtt gene, utilizing RNA interference (RNAi) to silence the mtt gene in fly eyes (homologous to the mammalian GRM6 gene) and construct a CSNB model. Through this approach, we observed significant defects in the eye structure and function upon reducing mtt expression in fly eyes. This manifested as disruptions in the compound eye lens structure and reduced sensitivity to light responses. These results suggest a critical role for mtt in the function of fly adult eyes. Interestingly, we found that the mtt gene is not expressed in the photoreceptor neurons of adult flies but is localized to the inner lamina neurons. In summary, these results underscore the crucial involvement of mtt in fly retinal function, providing a framework for understanding the pathogenic mechanisms of CSNB and facilitating research into potential therapeutic interventions.
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Affiliation(s)
- Wenfeng Chen
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Wenmiao Zhong
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Lingqi Yu
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Xiang Lin
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Jiayu Xie
- School of Medicine, Chongqing University, Chongqing 400044, China;
- State Key Laboratory of Resource Insects, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
| | - Zhenxing Liu
- State Key Laboratory of Resource Insects, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
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4
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Maddox JW, Ordemann GJ, Vázquez JDLR, Huang A, Gault C, Wisner SR, Randall K, Futagi D, DeVries SH, Hoon M, Lee A. A non-conducting role of the Ca v1.4 Ca 2+ channel drives homeostatic plasticity at the cone photoreceptor synapse. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570129. [PMID: 38106079 PMCID: PMC10723350 DOI: 10.1101/2023.12.05.570129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
In congenital stationary night blindness type 2 (CSNB2)-a disorder involving dysfunction of the Cav1.4 Ca2+ channel-visual impairment is relatively mild considering that Cav1.4 mediates synaptic transmission by rod and cone photoreceptors. Here, we addressed this conundrum using a Cav1.4 knockout (KO) mouse and a knock-in (KI) mouse expressing a non-conducting Cav1.4 mutant. Surprisingly, aberrant Cav3 currents were detected in cones of the KI and KO but not wild-type mice. Cone synapses, which fail to develop in KO mice, are present but enlarged in KI mice. Moreover, light responses in cone pathways and photopic visual behavior are preserved in KI but not in KO mice. In CSNB2, we propose that Cav3 channels maintain cone synaptic output provided that the Ca2+-independent role of Cav1.4 in cone synaptogenesis remains intact. Our findings reveal an unexpected form of homeostatic plasticity that relies on a non-canonical role of an ion channel.
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Affiliation(s)
- J. Wesley Maddox
- Dept of Neuroscience, University of Texas-Austin, Austin, TX 78712, USA
- These authors contributed equally
| | - Gregory J. Ordemann
- Dept of Neuroscience, University of Texas-Austin, Austin, TX 78712, USA
- These authors contributed equally
| | | | - Angie Huang
- Dept of Neuroscience, University of Texas-Austin, Austin, TX 78712, USA
| | - Christof Gault
- Dept of Neuroscience, University of Texas-Austin, Austin, TX 78712, USA
| | - Serena R. Wisner
- Dept. of Ophthalmology and Visual Sciences, University of Wisconsin- Madison, Madison, WI, 53706, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison WI 53706 USA
| | - Kate Randall
- Dept of Neuroscience, University of Texas-Austin, Austin, TX 78712, USA
| | - Daiki Futagi
- Dept. of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Steven H. DeVries
- Dept. of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Mrinalini Hoon
- Dept. of Ophthalmology and Visual Sciences, University of Wisconsin- Madison, Madison, WI, 53706, USA
- McPherson Eye Research Institute, Madison WI 53706 USA
| | - Amy Lee
- Dept of Neuroscience, University of Texas-Austin, Austin, TX 78712, USA
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5
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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.
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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
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6
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Zhou W, Jiang Z, Yi Z, Ouyang J, Li X, Zhang Q, Wang P. Defect of TIMP4 Is Associated with High Myopia and Participates in Rat Ocular Development in a Dose-Dependent Manner. Int J Mol Sci 2023; 24:16928. [PMID: 38069250 PMCID: PMC10707432 DOI: 10.3390/ijms242316928] [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: 10/12/2023] [Revised: 11/14/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Thinning of the sclera happens in myopia eyes owing to extracellular matrix (ECM) remodeling, but the initiators of the ECM remodeling in myopia are mainly unknown. The matrix metalloproteinase (MMPs) and tissue inhibitors of matrix metalloproteinase (TIMPs) regulate the homeostasis of the ECM. However, genetic studies of the MMPs and TIMPs in the occurrence of myopia are poor and limited. This study systematically investigated the association between twenty-nine genes of the TIMPs and MMPs families and early-onset high myopia (eoHM) based on whole exome sequencing data. Two TIMP4 heterozygous loss-of-function (LoF) variants, c.528C>A in six patients and c.234_235insAA in one patient, were statistically enriched in 928 eoHM probands compared to that in 5469 non-high myopia control (p = 3.7 × 10-5) and that in the general population (p = 2.78 × 10-9). Consequently, the Timp4 gene editing rat was further evaluated to explore the possible role of Timp4 on ocular and myopia development. A series of ocular morphology abnormalities in a dose-dependent manner (Timp4-/- < Timp4+/- < Timp4+/+) were observed in a rat model, including the decline in the retinal thickness, the elongation in the axial length, more vulnerable to the form deprivation model, morphology changes in sclera collagen bundles, and the decrease in collagen contents of the sclera and retina. Electroretinogram revealed that the b-wave amplitudes of Timp4 defect rats were significantly reduced, consistent with the shorter length of the bipolar axons detected by HE and IF staining. Heterozygous LoF variants in the TIMP4 are associated with early onset high myopia, and the Timp4 defect disturbs ocular development by influencing the morphology and function of the ocular tissue.
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Affiliation(s)
| | | | | | | | | | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510000, China; (W.Z.); (Z.J.); (Z.Y.); (J.O.); (X.L.)
| | - Panfeng Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510000, China; (W.Z.); (Z.J.); (Z.Y.); (J.O.); (X.L.)
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7
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Tsukamoto Y. Electrical synapses for a pooling layer of the convolutional neural network in retinas. Front Cell Neurosci 2023; 17:1281786. [PMID: 38026698 PMCID: PMC10648117 DOI: 10.3389/fncel.2023.1281786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/03/2023] [Indexed: 12/01/2023] Open
Abstract
We have an example of a synergetic effect between neuroscience and connectome via artificial intelligence. The invention of Neocognitron, a machine learning algorithm, was inspired by the visual cortical circuitry for complex cells to be made by combinations of simple cells, which uses a hierarchical convolutional neural network (CNN). The CNN machine learning algorithm is powerful in classifying neuron borderlines on electron micrograph images for automatized connectomic analysis. CNN is also useful as a functional framework to analyze the neurocircuitry of the visual system. The visual system encodes visual patterns in the retina and decodes them in the corresponding cortical areas. The knowledge of evolutionarily chosen mechanisms in retinas may help the innovation of new algorithms. Since over a half-century ago, a classical style of serial section transmission electron microscopy has vastly contributed to cell biology. It is still useful to comprehensively analyze the small area of retinal neurocircuitry that is rich in natural intelligence of pattern recognition. I discuss the perspective of our study on the primary rod signal pathway in mouse and macaque retinas with special reference to electrical synapses. Photon detection under the scotopic condition needs absolute sensitivity but no intricate pattern recognition. This extreme case is regarded as the most simplified pattern recognition of the input with no autocorrelation. A comparative study of mouse and macaque retinas, where exists the 7-fold difference in linear size, may give us the underlying principle with quantitative verification of their adaptational designs of neurocircuitry.
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Affiliation(s)
- Yoshihiko Tsukamoto
- Department of Biology, Hyogo Medical University, Nishinomiya, Hyogo, Japan
- Studio EM-Retina, Satonaka, Nishinomiya, Hyogo, Japan
- Center for Systems Vision Science, Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga, Japan
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8
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Seo H, Chung WG, Kwon YW, Kim S, Hong YM, Park W, Kim E, Lee J, Lee S, Kim M, Lim K, Jeong I, Song H, Park JU. Smart Contact Lenses as Wearable Ophthalmic Devices for Disease Monitoring and Health Management. Chem Rev 2023; 123:11488-11558. [PMID: 37748126 PMCID: PMC10571045 DOI: 10.1021/acs.chemrev.3c00290] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Indexed: 09/27/2023]
Abstract
The eye contains a complex network of physiological information and biomarkers for monitoring disease and managing health, and ocular devices can be used to effectively perform point-of-care diagnosis and disease management. This comprehensive review describes the target biomarkers and various diseases, including ophthalmic diseases, metabolic diseases, and neurological diseases, based on the physiological and anatomical background of the eye. This review also includes the recent technologies utilized in eye-wearable medical devices and the latest trends in wearable ophthalmic devices, specifically smart contact lenses for the purpose of disease management. After introducing other ocular devices such as the retinal prosthesis, we further discuss the current challenges and potential possibilities of smart contact lenses.
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Affiliation(s)
- Hunkyu Seo
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Won Gi Chung
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Yong Won Kwon
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Sumin Kim
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Yeon-Mi Hong
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Wonjung Park
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Enji Kim
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Jakyoung Lee
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Sanghoon Lee
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Moohyun Kim
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Kyeonghee Lim
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Inhea Jeong
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Hayoung Song
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
| | - Jang-Ung Park
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic
of Korea
- Department
of Neurosurgery, Yonsei University College
of Medicine, Seoul 03722, Republic of Korea
- Center
for Nanomedicine, Institute for Basic Science (IBS), Yonsei University, Seoul 03722, Republic
of Korea
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9
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Patil DN, Pantalone S, Cao Y, Laboute T, Novick SJ, Singh S, Savino S, Faravelli S, Magnani F, Griffin PR, Singh AK, Forneris F, Martemyanov KA. Structure of the photoreceptor synaptic assembly of the extracellular matrix protein pikachurin with the orphan receptor GPR179. Sci Signal 2023; 16:eadd9539. [PMID: 37490546 PMCID: PMC10561654 DOI: 10.1126/scisignal.add9539] [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] [Received: 07/14/2022] [Accepted: 07/06/2023] [Indexed: 07/27/2023]
Abstract
Precise synapse formation is essential for normal functioning of the nervous system. Retinal photoreceptors establish selective contacts with bipolar cells, aligning the neurotransmitter release apparatus with postsynaptic signaling cascades. This involves transsynaptic assembly between the dystroglycan-dystrophin complex on the photoreceptor and the orphan receptor GPR179 on the bipolar cell, which is mediated by the extracellular matrix protein pikachurin (also known as EGFLAM). This complex plays a critical role in the synaptic organization of photoreceptors and signal transmission, and mutations affecting its components cause blinding disorders in humans. Here, we investigated the structural organization and molecular mechanisms by which pikachurin orchestrates transsynaptic assembly and solved structures of the human pikachurin domains by x-ray crystallography and of the GPR179-pikachurin complex by single-particle, cryo-electron microscopy. The structures reveal molecular recognition principles of pikachurin by the Cache domains of GPR179 and show how the interaction is involved in the transsynaptic alignment of the signaling machinery. Together, these data provide a structural basis for understanding the synaptic organization of photoreceptors and ocular pathology.
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Affiliation(s)
- Dipak N. Patil
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL 33458, USA
| | - Serena Pantalone
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Via Ferrata, 9A, I-27100 Pavia, Italy
| | - Yan Cao
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL 33458, USA
| | - Thibaut Laboute
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL 33458, USA
| | - Scott J. Novick
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL 33458, USA
| | - Shikha Singh
- Department of Biological Sciences, Columbia University New York, NY 10027, USA
| | - Simone Savino
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Via Ferrata, 9A, I-27100 Pavia, Italy
| | - Silvia Faravelli
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Via Ferrata, 9A, I-27100 Pavia, Italy
| | - Francesca Magnani
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Via Ferrata, 9A, I-27100 Pavia, Italy
| | - Patrick R. Griffin
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL 33458, USA
| | - Appu K. Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
- Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Federico Forneris
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Via Ferrata, 9A, I-27100 Pavia, Italy
- Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Kirill A. Martemyanov
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL 33458, USA
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10
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Gupta AK, Haas-Neill S, Talukder M. The safety of oral antifungals for the treatment of onychomycosis. Expert Opin Drug Saf 2023; 22:1169-1178. [PMID: 37925672 DOI: 10.1080/14740338.2023.2280137] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 11/02/2023] [Indexed: 11/07/2023]
Abstract
INTRODUCTION Oral antifungals are used for the treatment of moderate-severe onychomycosis. Terbinafine and itraconazole are approved for onychomycosis treatment in North America; additionally, fluconazole is indicated for onychomycosis in Europe. Other oral antifungals such as ketoconazole and griseofulvin are no longer used for the treatment of onychomycosis due to safety concerns and relatively lower efficacy. SEARCH STRATEGY On 7 March 2023, we conducted a comprehensive search in PubMed and Google Scholar, while also manually examining selected article bibliographies and package inserts. AREAS COVERED Terbinafine, itraconazole, and fluconazole have several interactions with cytochrome-p450, and either alone, or when co-administered with other drugs these interactions can facilitate a multitude of adverse events. This article identifies possible hepatic, renal, cutaneous, cardiovascular, neurological, hemopoietic, and obstetric adverse events. We have also compared the rates of hepatotoxicity, clinically apparent liver injury, and alanine transaminase elevations between oral antifungals, and recommendations for hepatic monitoring. EXPERT OPINION We recommend laboratory testing of liver function tests prior to the administration of any oral antifungals, especially when clinically indicated. In the event of a first treatment failure, the diagnosis of onychomycosis must be confirmed, and consideration given to antifungal susceptibility testing. Antifungal stewardship will help reduce the incidence of antifungal resistance.
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Affiliation(s)
- Aditya K Gupta
- Mediprobe Research Inc, London, ON, Canada
- Division of Dermatology, Department of Medicine, University of Toronto, Toronto, Canada
| | | | - Mesbah Talukder
- Mediprobe Research Inc, London, ON, Canada
- School of Pharmacy, BRAC University, Dhaka, Bangladesh
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11
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Fehlhaber KE, Majumder A, Boyd KK, Griffis KG, Artemyev NO, Fain GL, Sampath AP. A Novel Role for UNC119 as an Enhancer of Synaptic Transmission. Int J Mol Sci 2023; 24:8106. [PMID: 37175812 PMCID: PMC10178850 DOI: 10.3390/ijms24098106] [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: 03/30/2023] [Revised: 04/22/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Mammalian UNC119 is a ciliary trafficking chaperone highly expressed in the inner segment of retinal photoreceptors. Previous research has shown that UNC119 can bind to transducin, the synaptic ribbon protein RIBEYE, and the calcium-binding protein CaBP4, suggesting that UNC119 may have a role in synaptic transmission. We made patch-clamp recordings from retinal slices in mice with the UNC119 gene deleted and showed that removal of even one gene of UNC119 has no effect on the rod outer segment photocurrent, but acted on bipolar cells much like background light: it depolarized membrane potential, decreased sensitivity, accelerated response decay, and decreased the Hill coefficient of the response-intensity relationship. Similar effects were seen on rod bipolar-cell current and voltage responses, and after exposure to bright light to translocate transducin into the rod inner segment. These findings indicate that UNC119 deletion reduces the steady-state glutamate release rate at rod synapses, though no change in the voltage dependence of the synaptic Ca current was detected. We conclude that UNC119, either by itself or together with transducin, can facilitate the release of glutamate at rod synapses, probably by some interaction with RIBEYE or other synaptic proteins rather than by binding to CaBP4 or calcium channels.
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Affiliation(s)
- Katherine E. Fehlhaber
- Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA (G.L.F.)
| | - Anurima Majumder
- Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA (N.O.A.)
| | - Kimberly K. Boyd
- Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA (N.O.A.)
| | - Khris G. Griffis
- Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA (G.L.F.)
| | - Nikolai O. Artemyev
- Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA (N.O.A.)
- Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Gordon L. Fain
- Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA (G.L.F.)
| | - Alapakkam P. Sampath
- Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA (G.L.F.)
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12
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Chan YJ, Hsiao G, Wan WN, Yang TM, Tsai CH, Kang JJ, Lee YC, Fang TC, Cheng YW, Li CH. Blue light exposure collapses the inner blood-retinal barrier by accelerating endothelial CLDN5 degradation through the disturbance of GNAZ and the activation of ADAM17. Fluids Barriers CNS 2023; 20:31. [PMID: 37095509 PMCID: PMC10124034 DOI: 10.1186/s12987-023-00430-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 04/07/2023] [Indexed: 04/26/2023] Open
Abstract
Blue light is part of the natural light spectrum that emits high energy. Currently, people are frequently exposed to blue light from 3C devices, resulting in a growing incidence of retinopathy. The retinal vasculature is complex, and retinal vessels not only serve the metabolic needs of the retinal sublayers, but also maintain electrolyte homeostasis by forming the inner blood-retinal barrier (iBRB). The iBRB, which is primarily composed of endothelial cells, has well-developed tight junctions. However, with exposure to blue light, the risks of targeting retinal endothelial cells are currently unknown. We found that endothelial claudin-5 (CLDN5) was rapidly degraded under blue light, coinciding with the activation of a disintegrin and metalloprotease 17 (ADAM17), even at non-cytotoxic lighting. An apparently broken tight junction and a permeable paracellular cleft were observed. Mice exposed to blue light displayed iBRB leakage, conferring attenuation of the electroretinogram b-wave and oscillatory potentials. Both pharmacological and genetic inhibition of ADAM17 remarkably alleviated CLDN5 degradation induced by blue light. Under untreated condition, ADAM17 is sequestered by GNAZ (a circadian-responsive, retina-enriched inhibitory G protein), whereas ADAM17 escapes from GNAZ by blue light illuminance. GNAZ knockdown led to ADAM17 hyperactivation, CLDN5 downregulation, and paracellular permeability in vitro, and retinal damage mimicked blue light exposure in vivo. These data demonstrate that blue light exposure might impair the iBRB by accelerating CLDN5 degradation through the disturbance of the GNAZ-ADAM17 axis.
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Affiliation(s)
- Yen-Ju Chan
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
- School of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
| | - George Hsiao
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
- TMU Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan
| | - Wang-Nok Wan
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
| | - Tsung-Min Yang
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
- School of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
| | - Chi-Hao Tsai
- Department of Ophthalmology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jaw-Jou Kang
- Institute of Food Safety and Health Risk Assessment, School of Pharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan
| | - Yu-Cheng Lee
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Te-Chao Fang
- TMU Research Center of Urology and Kidney, Taipei Medical University, Taipei, Taiwan
- Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yu-Wen Cheng
- School of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan.
- TMU Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan.
| | - Ching-Hao Li
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan.
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
- TMU Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan.
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13
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Rotov AY, Firsov ML. Optogenetic Prosthetization of Retinal Bipolar Cells. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022060011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Abstract
Although the experience of optogenetic retinal prosthetics
in animal models dates back to more than 16 years, the first results
obtained on humans have only been reported in the last year. Over this
period, the main challenges of prosthetics became clear and the
approaches to their solution were proposed. In this review, we aim
to present the achievements in the field of optogenetic prosthetization
of retinal bipolar cells with a focus mainly on relatively recent
publications. The review addresses the advantages and disadvantages
of bipolar cell prosthetics as compared to the alternative target,
retinal ganglion cells, and provides a comparative analysis of the
effectiveness of ionotropic light-sensitive proteins (channelrhodopsins)
or metabotropic receptors (rhodopsins) as prosthetic tools.
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14
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Tsukamoto Y, Omi N. Multiple Invagination Patterns and Synaptic Efficacy in Primate and Mouse Rod Synaptic Terminals. Invest Ophthalmol Vis Sci 2022; 63:11. [PMID: 35819284 PMCID: PMC9287620 DOI: 10.1167/iovs.63.8.11] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Optical retina images are scaled based on eye size, which results in a linear scale ratio of 10:1 for human versus mouse and 7:1 for macaque monkey versus mouse. We examined how this scale difference correlates with the structural configuration of synaptic wiring in the rod spherule (RS) between macaque and mouse retinas compared with human data. Methods Rod bipolar cell (BC) dendrites and horizontal cell (HC) axonal processes, which invaginate the RS to form synaptic ribbon-associated triads, were examined by serial section transmission electron microscopy. Results The number of rod BC invaginating dendrites ranged 1∼4 in the macaque RS but only 1∼2 in the mouse. Approximately 40% of those dendrites bifurcated into two central elements in the macaque, but 2% of those dendrites did in the mouse. Both factors gave rise to 10 invagination patterns of BC and HC neurites in the macaque RS but only two in the mouse. Five morphological parameters: the lengths of arciform densities and ribbons, the area of the BC-RS contact, and the surface areas of BC and HC invaginating neurites, were all independent of the invagination patterns in the macaque RS. However, those parameters were significantly greater in the macaque than in the mouse by ratios of 1.5∼1.8. Conclusions The primate RS provides a more expansive BC-RS interface associated with the longer arciform density and more branched invaginating neurites of BCs and HCs than the mouse RS. The resulting greater synaptic contact area may contribute to more efficient signal transfer.
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Affiliation(s)
- Yoshihiko Tsukamoto
- Department of Biology, Hyogo College of Medicine, Mukogawa, Nishinomiya, Hyogo, Japan.,Studio EM-Retina, Satonaka, Nishinomiya, Hyogo, Japan.,Center for Systems Vision Science, Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Naoko Omi
- Studio EM-Retina, Satonaka, Nishinomiya, Hyogo, Japan
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15
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Gilhooley MJ, Lindner M, Palumaa T, Hughes S, Peirson SN, Hankins MW. A systematic comparison of optogenetic approaches to visual restoration. Mol Ther Methods Clin Dev 2022; 25:111-123. [PMID: 35402632 PMCID: PMC8956963 DOI: 10.1016/j.omtm.2022.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/04/2022] [Indexed: 02/06/2023]
Abstract
During inherited retinal degenerations (IRDs), vision is lost due to photoreceptor cell death; however, a range of optogenetic tools have been shown to restore light responses in animal models. Restored response characteristics vary between tools and the neuronal cell population to which they are delivered: the interplay between these is complex, but targeting upstream neurons (such as retinal bipolar cells) may provide functional benefit by retaining intraretinal signal processing. In this study, our aim was to compare two optogenetic tools: mammalian melanopsin (hOPN4) and microbial red-shifted channelrhodopsin (ReaChR) expressed within two subpopulations of surviving cells in a degenerate retina. Intravitreal adeno-associated viral vectors and mouse models utilising the Cre/lox system restricted expression to populations dominated by bipolar cells or retinal ganglion cells and was compared with non-targeted delivery using the chicken beta actin (CBA) promoter. In summary, we found bipolar-targeted optogenetic tools produced faster kinetics and flatter intensity-response relationships compared with non-targeted or retinal-ganglion-cell-targeted hOPN4. Hence, optogenetic tools of both mammalian and microbial origins show advantages when targeted to bipolar cells. This demonstrates the advantage of bipolar-cell-targeted optogenetics for vision restoration in IRDs. We therefore developed a bipolar-cell-specific gene delivery system employing a compressed promoter with the potential for clinical translation.
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Affiliation(s)
- Michael J. Gilhooley
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
- Jules Thorne SCNi, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
- The Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
- Moorfields Eye Hospital, 162, City Road, London EC1V 2PD, UK
| | - Moritz Lindner
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
- Jules Thorne SCNi, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstrasse 1-2, Marburg 35037, Germany
| | - Teele Palumaa
- Jules Thorne SCNi, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
- East Tallinn Central Hospital Eye Clinic, Ravi 18, 10138 Tallinn, Estonia
| | - Steven Hughes
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
- Jules Thorne SCNi, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
| | - Stuart N. Peirson
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
- Jules Thorne SCNi, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
| | - Mark W. Hankins
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
- Jules Thorne SCNi, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK
- Corresponding author Mark W. Hankins, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX1 3QU, UK.
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16
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Yan J, Li Y, Zhang T, Shen Y. Numb deficiency impairs retinal structure and visual function in mice. Exp Eye Res 2022; 219:109066. [DOI: 10.1016/j.exer.2022.109066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/20/2022] [Accepted: 04/02/2022] [Indexed: 11/25/2022]
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17
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AMIGO1 Promotes Axon Growth and Territory Matching in the Retina. J Neurosci 2022; 42:2678-2689. [PMID: 35169021 PMCID: PMC8973419 DOI: 10.1523/jneurosci.1164-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 01/17/2022] [Accepted: 01/23/2022] [Indexed: 11/21/2022] Open
Abstract
Dendrite and axon arbor sizes are critical to neuronal function and vary widely between different neuron types. The relative dendrite and axon sizes of synaptic partners control signal convergence and divergence in neural circuits. The developmental mechanisms that determine cell-type-specific dendrite and axon size and match synaptic partners' arbor territories remain obscure. Here, we discover that retinal horizontal cells express the leucine-rich repeat domain cell adhesion molecule AMIGO1. Horizontal cells provide pathway-specific feedback to photoreceptors-horizontal cell axons to rods and horizontal cell dendrites to cones. AMIGO1 selectively expands the size of horizontal cell axons. When Amigo1 is deleted in all or individual horizontal cells of either sex, their axon arbors shrink. By contrast, horizontal cell dendrites and synapse formation of horizontal cell axons and dendrites are unaffected by AMIGO1 removal. The dendrites of rod bipolar cells, which do not express AMIGO1, shrink in parallel with horizontal cell axons in Amigo1 knockout (Amigo1 KO) mice. This territory matching maintains the function of the rod bipolar pathway, preserving bipolar cell responses and retinal output signals in Amigo1 KO mice. We previously identified AMIGO2 as a scaling factor that constrains retinal neurite arbors. Our current results identify AMIGO1 as a scaling factor that expands retinal neurite arbors and reveal territory matching as a novel homeostatic mechanism. Territory matching interacts with other homeostatic mechanisms to stabilize the development of the rod bipolar pathway, which mediates vision near the threshold.SIGNIFICANCE STATEMENT Neurons send and receive signals through branched axonal and dendritic arbors. The size of these arbors is critical to the function of a neuron. Axons and dendrites grow during development and are stable at maturity. The mechanisms that determine axon and dendrite size are not well understood. Here, we identify a cell surface protein, AMIGO1, that selectively promotes axon growth of horizontal cells, a retinal interneuron. Removal of AMIGO1 reduces the size of horizontal cell axons without affecting the size of their dendrites or the ability of both arbors to form connections. The changes in horizontal cell axons are matched by changes in synaptic partner dendrites to stabilize retinal function. This identifies territory matching as a novel homeostatic plasticity mechanism.
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18
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Schilardi G, Kleinlogel S. Two Functional Classes of Rod Bipolar Cells in the Healthy and Degenerated Optogenetically Treated Murine Retina. Front Cell Neurosci 2022; 15:809531. [PMID: 35095426 PMCID: PMC8793500 DOI: 10.3389/fncel.2021.809531] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/20/2021] [Indexed: 11/25/2022] Open
Abstract
Bipolar cells have become successful targets for optogenetic gene therapies that restore vision after photoreceptor degeneration. However, degeneration was shown to cause changes in neuronal connectivity and protein expression, which may impact the quality of synthetically restored signaling. Further, the expression of an optogenetic protein may alter passive membrane properties of bipolar cells affecting signal propagation. We here investigated the passive membrane properties of rod bipolar cells in three different systems, the healthy retina, the degenerated retina, and the degenerated retina expressing the optogenetic actuator Opto-mGluR6. We found that, based on the shape of their current-voltage relations, rod bipolar cells in healthy and degenerated retinas form two clear functional groups (type 1 and type 2 cells). Depolarizing the membrane potential changed recorded current-voltage curves from type 1 to type 2, confirming a single cell identity with two functional states. Expression of Opto-mGluR6 did not alter the passive properties of the rod bipolar cell. With progressing degeneration, dominant outward rectifying currents recorded in type 2 rod bipolar cells decreased significantly. We demonstrate that this is caused by a downregulation of BK channel expression in the degenerated retina. Since this BK conductance will normally recover the membrane potential after RBCs are excited by open TRPM1 channels, a loss in BK will decrease high-pass filtering at the rod bipolar cell level. A better understanding of the changes of bipolar cell physiology during retinal degeneration may pave the way to optimize future treatment strategies of blindness.
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19
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Young BK, Ramakrishnan C, Ganjawala T, Wang P, Deisseroth K, Tian N. An uncommon neuronal class conveys visual signals from rods and cones to retinal ganglion cells. Proc Natl Acad Sci U S A 2021; 118:e2104884118. [PMID: 34702737 PMCID: PMC8612366 DOI: 10.1073/pnas.2104884118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 01/01/2023] Open
Abstract
Neurons in the central nervous system (CNS) are distinguished by the neurotransmitter types they release, their synaptic connections, morphology, and genetic profiles. To fully understand how the CNS works, it is critical to identify all neuronal classes and reveal their synaptic connections. The retina has been extensively used to study neuronal development and circuit formation. Here, we describe a previously unidentified interneuron in mammalian retina. This interneuron shares some morphological, physiological, and molecular features with retinal bipolar cells, such as receiving input from photoreceptors and relaying visual signals to retinal ganglion cells. It also shares some features with amacrine cells (ACs), particularly Aii-ACs, such as their neurite morphology in the inner plexiform layer, the expression of some AC-specific markers, and possibly the release of the inhibitory neurotransmitter glycine. Thus, we unveil an uncommon interneuron, which may play an atypical role in vision.
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Affiliation(s)
- Brent K Young
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT 84132
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84114
| | | | - Tushar Ganjawala
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48202
| | - Ping Wang
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT 84132
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Ning Tian
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT 84132;
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84114
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84132
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84132
- Veterans Affairs Medical Center, Salt Lake City, UT 84148
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20
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Kralik J, Kleinlogel S. Functional Availability of ON-Bipolar Cells in the Degenerated Retina: Timing and Longevity of an Optogenetic Gene Therapy. Int J Mol Sci 2021; 22:ijms222111515. [PMID: 34768944 PMCID: PMC8584043 DOI: 10.3390/ijms222111515] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/13/2021] [Accepted: 10/23/2021] [Indexed: 01/19/2023] Open
Abstract
Degenerative diseases of the retina are responsible for the death of photoreceptors and subsequent loss of vision in patients. Nevertheless, the inner retinal layers remain intact over an extended period of time, enabling the restoration of light sensitivity in blind retinas via the expression of optogenetic tools in the remaining retinal cells. The chimeric Opto-mGluR6 protein represents such a tool. With exclusive ON-bipolar cell expression, it combines the light-sensitive domains of melanopsin and the intracellular domains of the metabotropic glutamate receptor 6 (mGluR6), which naturally mediates light responses in these cells. Albeit vision restoration in blind mice by Opto-mGluR6 delivery was previously shown, much is left to be explored in regard to the effects of the timing of the treatment in the degenerated retina. We performed a functional evaluation of Opto-mGluR6-treated murine blind retinas using multi-electrode arrays (MEAs) and observed long-term functional preservation in the treated retinas, as well as successful therapeutical intervention in later stages of degeneration. Moreover, the treatment decreased the inherent retinal hyperactivity of the degenerated retinas to levels undistinguishable from healthy controls. Finally, we observed for the first time micro electroretinograms (mERGs) in optogenetically treated animals, corroborating the origin of Opto-mGluR6 signalling at the level of mGluR6 of ON-bipolar cells.
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21
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Jiang X, Mahroo OA. Negative electroretinograms: genetic and acquired causes, diagnostic approaches and physiological insights. Eye (Lond) 2021; 35:2419-2437. [PMID: 34127841 PMCID: PMC8377097 DOI: 10.1038/s41433-021-01604-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/05/2021] [Accepted: 05/10/2021] [Indexed: 02/07/2023] Open
Abstract
The dark-adapted human electroretinogram (ERG) response to a standard bright flash includes a negative-going a-wave followed by a positive-going b-wave that crosses the baseline. An electronegative waveform (or negative ERG) results when the b-wave is selectively reduced such that the ERG fails to cross the baseline following the a-wave. In the context of a normally sized a-wave, it indicates a site of retinal dysfunction occurring after phototransduction (commonly at the photoreceptor to bipolar cell synapse). This is an important finding. In genetic disease, the pattern of ERG abnormality can point to variants in a small group of genes (frequently those associated with congenital stationary night blindness and X-linked retinoschisis, but negative ERGs can also be seen in other conditions including syndromic disease). In acquired disease, there are numerous causes, but specific features may point to melanoma-associated retinopathy (MAR). In some cases, the visual symptoms precede the diagnosis of the melanoma and so the ERG findings can initiate investigations facilitating early detection and treatment. Negative ERGs can occur in other paraneoplastic conditions, and in a range of other diseases. This review will outline the physiological basis for the negative ERG, report prevalences in the literature from different cohorts, discuss the range of causes, displaying examples of a number of ERG phenotypes, highlight features of a clinical approach to patients, and briefly discuss further insights relating to current flows shaping the a-wave trough and from single-cell transcriptome analysis.
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Affiliation(s)
- Xiaofan Jiang
- grid.83440.3b0000000121901201Institute of Ophthalmology, University College London, London, UK ,grid.439257.e0000 0000 8726 5837Retinal and Genetics Services, Moorfields Eye Hospital, London, UK ,grid.425213.3Section of Ophthalmology and Department of Twin Research and Genetic Epidemiology, King’s College London, St Thomas’ Hospital Campus, London, UK
| | - Omar A. Mahroo
- grid.83440.3b0000000121901201Institute of Ophthalmology, University College London, London, UK ,grid.439257.e0000 0000 8726 5837Retinal and Genetics Services, Moorfields Eye Hospital, London, UK ,grid.425213.3Section of Ophthalmology and Department of Twin Research and Genetic Epidemiology, King’s College London, St Thomas’ Hospital Campus, London, UK ,grid.5335.00000000121885934Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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22
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Ellis EM, Frederiksen R, Morshedian A, Fain GL, Sampath AP. Separate ON and OFF pathways in vertebrate vision first arose during the Cambrian. Curr Biol 2021; 30:R633-R634. [PMID: 32516608 DOI: 10.1016/j.cub.2020.04.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Ellis et al. show that retinal ON and OFF bipolar cells, and the novel metabotropic glutamate receptors of ON bipolar-cell dendrites, are both present in lamprey. They conclude that the fundamental organizing principle of separate ON and OFF pathways first appeared in the vertebrate visual system over 500 million years ago in the late Cambrian.
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Affiliation(s)
- Erika M Ellis
- Department of Ophthalmology and Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Rikard Frederiksen
- Department of Ophthalmology and Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ala Morshedian
- Department of Ophthalmology and Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Gordon L Fain
- Department of Ophthalmology and Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA.
| | - Alapakkam P Sampath
- Department of Ophthalmology and Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA.
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Abstract
Time is largely a hidden variable in vision. It is the condition for seeing interesting things such as spatial forms and patterns, colours and movements in the external world, and yet is not meant to be noticed in itself. Temporal aspects of visual processing have received comparatively little attention in research. Temporal properties have been made explicit mainly in measurements of resolution and integration in simple tasks such as detection of spatially homogeneous flicker or light pulses of varying duration. Only through a mechanistic understanding of their basis in retinal photoreceptors and circuits can such measures guide modelling of natural vision in different species and illuminate functional and evolutionary trade-offs. Temporal vision research would benefit from bridging traditions that speak different languages. Towards that goal, I here review studies from the fields of human psychophysics, retinal physiology and neuroethology, with a focus on fundamental constraints set by early vision. Summary: Simple measures of temporal vision such as the critical flicker frequency can be useful for modelling natural vision only if their relationship to photoreceptor responses and retinal processing is understood.
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Affiliation(s)
- Kristian Donner
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland
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Südhof TC. The cell biology of synapse formation. J Cell Biol 2021; 220:e202103052. [PMID: 34086051 PMCID: PMC8186004 DOI: 10.1083/jcb.202103052] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 04/25/2023] Open
Abstract
In a neural circuit, synapses transfer information rapidly between neurons and transform this information during transfer. The diverse computational properties of synapses are shaped by the interactions between pre- and postsynaptic neurons. How synapses are assembled to form a neural circuit, and how the specificity of synaptic connections is achieved, is largely unknown. Here, I posit that synaptic adhesion molecules (SAMs) organize synapse formation. Diverse SAMs collaborate to achieve the astounding specificity and plasticity of synapses, with each SAM contributing different facets. In orchestrating synapse assembly, SAMs likely act as signal transduction devices. Although many candidate SAMs are known, only a few SAMs appear to have a major impact on synapse formation. Thus, a limited set of collaborating SAMs likely suffices to account for synapse formation. Strikingly, several SAMs are genetically linked to neuropsychiatric disorders, suggesting that impairments in synapse assembly are instrumental in the pathogenesis of neuropsychiatric disorders.
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Tsukamoto Y, Iseki K, Omi N. Helical Fasciculation of Bipolar and Horizontal Cell Neurites for Wiring With Photoreceptors in Macaque and Mouse Retinas. Invest Ophthalmol Vis Sci 2021; 62:31. [PMID: 33507230 PMCID: PMC7846946 DOI: 10.1167/iovs.62.1.31] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The three-dimensional configurations of rod and cone bipolar cell (BC) dendrites and horizontal cell (HC) processes outside rod and cone synaptic terminals have not been fully elucidated. We reveal how these neurites are mutually arranged to coordinate formation and maintenance of the postsynaptic complex of ribbon synapses in mouse and monkey retinas. Methods Serial section transmission electron microscopy was utilized to reconstruct BC and HC neurites in macaque monkey and mouse, including metabotropic glutamate receptor 6 (mGluR6)-knockout mice. Results Starting from sporadically distributed branching points, rod BC and HC neurites (B and H, respectively) took specific paths to rod spherules by gradually adjusting their mutual positions, which resulted in a closed alternating pattern of H‒B‒H‒B neurites at the rod spherule aperture. This order corresponded to the array of elements constituting the postsynaptic complex of ribbon synapses. We identified novel helical coils of HC processes surrounding the rod BC dendrite in both mouse and macaque retinas, and these structures occurred more frequently in mGluR6-knockout than wild-type mouse retinas. Horizontal cell processes also formed hook-like protrusions that encircled cone BC and HC neurites below the cone pedicles in the macaque retina. Conclusions Bipolar and horizontal cell neurites take specific paths to adjust their mutual positions at the rod spherule aperture. Some HC processes are helically coiled around rod BC dendrites or form hook-like protrusions around cone BC dendrites and HC processes. Loss of mGluR6 signaling may be one factor promoting unbalanced neurite growth and compensatory neurite coiling.
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Affiliation(s)
- Yoshihiko Tsukamoto
- Department of Biology, Hyogo College of Medicine, Mukogawa, Nishinomiya, Hyogo, Japan.,Studio EM-Retina, Satonaka, Nishinomiya, Hyogo, Japan
| | - Kyoko Iseki
- Laboratory for Retinal Regeneration, RIKEN Center for Developmental Biology, Minatojima Minamimachi, Chuo-ku, Kobe, Hyogo, Japan
| | - Naoko Omi
- Studio EM-Retina, Satonaka, Nishinomiya, Hyogo, Japan
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Barboni MTS, Dias SL, Silva LA, Damico FM, Vidal KS, Costa MF, Nagy BV, Kremers J, Ventura DF. Correlations Between Dark-Adapted Rod Threshold Elevations and ERG Response Deficits in Duchenne Muscular Dystrophy. Invest Ophthalmol Vis Sci 2021; 62:29. [PMID: 33891680 PMCID: PMC8083068 DOI: 10.1167/iovs.62.4.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Purpose The purpose of this study was to characterize changes in the full-field flash electroretinogram (ERG) in association with psychophysical dark-adapted visual thresholds in patients with genetically characterized Duchenne muscular dystrophy (DMD) either lacking Dp427 (Up 30) or at least Dp260 in addition to Dp427 (Down 30). Methods Twenty-one patients with DMD and 27 age-similar controls participated in this study. Dark-adapted (0.01, 3.0, and 10 cd.s/m² flashes) and light-adapted (3.0 cd.s/m² flash) ERGs were recorded following International Society for Clinical Electrophysiology of Vision (ISCEV) standard protocols. Visual detection thresholds to 625-nm (cone function) and 527-nm (rod function) light-emitting diode (LED) flashes (2 degree diameter) were measured during a dark adaptation period after a 1-minute exposure to a bleaching light (3000 cd/m²). Initially, 8 minutes of interleaved 625-nm and 527-nm thresholds were measured. After an additional 5 minutes of dark-adaptation, a second set of threshold measurements to 527-nm stimuli was performed during the subsequent 6 minutes. Results Dark-adapted b-wave amplitude was significantly reduced to all strengths of flash and a-wave in response to the strong flash stimulus was delayed (15.6 vs. 14.7 ms, P < 0.05) in patients with Down 30 compared with controls. Dark-adapted cone thresholds did not differ among the groups (−2.0, −1.8, and −1.7 log cd/m² for Down 30, Up 30, and controls, respectively, P = 0.21). In contrast, dark-adapted rod thresholds were elevated (F(2,36) = 8.537, P = 0.001) in patients with Down 30 (mean = −3.2 ± 1.1 log cd/m²) relative to controls (mean = −4.2 ± 0.3 log cd/m²). Dark-adapted b-wave amplitudes were correlated with dark-adapted rod sensitivity in patients with DMD (Spearman Rho = 0.943, P = 0.005). The changes were much smaller or absent in patients with intact Dp260. Conclusions Dp260 is particularly required for normal rod-system function in dark adaptation.
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Affiliation(s)
- Mirella Telles Salgueiro Barboni
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary.,Department of Experimental Psychology, Institute of Psychology, University of Sao Paulo, Brazil
| | - Sarah Leonardo Dias
- Department of Experimental Psychology, Institute of Psychology, University of Sao Paulo, Brazil
| | | | - Francisco Max Damico
- Department of Experimental Psychology, Institute of Psychology, University of Sao Paulo, Brazil.,Department of Ophthalmology, Faculty of Medicine, University of Sao Paulo, Brazil
| | - Kallene Summer Vidal
- Department of Experimental Psychology, Institute of Psychology, University of Sao Paulo, Brazil
| | - Marcelo Fernandes Costa
- Department of Experimental Psychology, Institute of Psychology, University of Sao Paulo, Brazil
| | - Balázs Vince Nagy
- Department of Mechatronics, Optics and Mechanical Engineering Informatics, Budapest University of Technology and Economics, Budapest, Hungary
| | - Jan Kremers
- Section for Retinal Physiology, University Hospital Erlangen, Erlangen, Germany
| | - Dora Fix Ventura
- Department of Experimental Psychology, Institute of Psychology, University of Sao Paulo, Brazil
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Murenu E, Pavlou M, Richter L, Rapti K, Just S, Cehajic-Kapetanovic J, Tafrishi N, Hayes A, Scholey R, Lucas R, Büning H, Grimm D, Michalakis S. A universal protocol for isolating retinal ON bipolar cells across species via fluorescence-activated cell sorting. Mol Ther Methods Clin Dev 2021; 20:587-600. [PMID: 33665228 PMCID: PMC7895692 DOI: 10.1016/j.omtm.2021.01.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/19/2021] [Indexed: 11/17/2022]
Abstract
Inherited retinal dystrophies (IRDs) are characterized by progressive degeneration and loss of light-sensing photoreceptors. The most promising therapeutic approach for IRDs is gene supplementation therapy using viral vectors, which requires the presence of viable photoreceptors at the time of intervention. At later disease stages, photoreceptors are lost and can no longer be rescued with this approach. For these patients, conferring light-sensing abilities to the remaining interneurons of the ON circuit (i.e., ON bipolar cells) using optogenetic tools poses an alternative treatment strategy. Such treatments, however, are hampered by the lack of efficient gene delivery tools targeting ON bipolar cells, which in turn rely on the effective isolation of these cells to facilitate tool development. Herein, we describe a method to selectively isolate ON bipolar cells via fluorescence-activated cell sorting (FACS), based on the expression of two intracellular markers. We show that the method is compatible with highly sensitive downstream analyses and suitable for the isolation of ON bipolar cells from healthy as well as degenerated mouse retinas. Moreover, we demonstrate that this approach works effectively using non-human primate (NHP) retinal tissue, thereby offering a reliable pipeline for universal screening strategies that do not require inter-species adaptations or transgenic animals.
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Affiliation(s)
- Elisa Murenu
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
- Department of Pharmacy, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Marina Pavlou
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
- Department of Pharmacy, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Lisa Richter
- Core Facility Flow Cytometry, Biomedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Kleopatra Rapti
- Department of Infectious Diseases/Virology, Medical Faculty, University of Heidelberg, 69120 Heidelberg, Germany
- BioQuant Center, University of Heidelberg, 69120 Heidelberg, Germany
| | - Sabrina Just
- Laboratory for Infection Biology and Gene Transfer, Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University and Oxford University Hospitals, Oxford OX3 9DU, UK
| | - Neda Tafrishi
- Core Facility Flow Cytometry, Gene Center, BioSysM, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Andrew Hayes
- Center for Biological Timing & School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Rachel Scholey
- Center for Biological Timing & School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Robert Lucas
- Center for Biological Timing & School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Hildegard Büning
- Laboratory for Infection Biology and Gene Transfer, Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, Hannover Medical School, 30625 Hannover, Germany
- German Center for Infection Research (DZIF), partner site, Hannover, Germany
| | - Dirk Grimm
- Department of Infectious Diseases/Virology, Medical Faculty, University of Heidelberg, 69120 Heidelberg, Germany
- BioQuant Center, University of Heidelberg, 69120 Heidelberg, Germany
- German Center for Infection Research (DZIF) and German Center for Cardiovascular Research (DZHK), partner site, Heidelberg, Germany
| | - Stylianos Michalakis
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
- Department of Pharmacy, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
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28
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Korecki AJ, Cueva-Vargas JL, Fornes O, Agostinone J, Farkas RA, Hickmott JW, Lam SL, Mathelier A, Zhou M, Wasserman WW, Di Polo A, Simpson EM. Human MiniPromoters for ocular-rAAV expression in ON bipolar, cone, corneal, endothelial, Müller glial, and PAX6 cells. Gene Ther 2021; 28:351-372. [PMID: 33531684 PMCID: PMC8222000 DOI: 10.1038/s41434-021-00227-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/17/2020] [Accepted: 01/15/2021] [Indexed: 02/06/2023]
Abstract
Small and cell-type restricted promoters are important tools for basic and preclinical research, and clinical delivery of gene therapies. In clinical gene therapy, ophthalmic trials have been leading the field, with over 50% of ocular clinical trials using promoters that restrict expression based on cell type. Here, 19 human DNA MiniPromoters were bioinformatically designed for rAAV, tested by neonatal intravenous delivery in mouse, and successful MiniPromoters went on to be tested by intravitreal, subretinal, intrastromal, and/or intravenous delivery in adult mouse. We present promoter development as an overview for each cell type, but only show results in detail for the recommended MiniPromoters: Ple265 and Ple341 (PCP2) ON bipolar, Ple349 (PDE6H) cone, Ple253 (PITX3) corneal stroma, Ple32 (CLDN5) endothelial cells of the blood-retina barrier, Ple316 (NR2E1) Müller glia, and Ple331 (PAX6) PAX6 positive. Overall, we present a resource of new, redesigned, and improved MiniPromoters for ocular gene therapy that range in size from 784 to 2484 bp, and from weaker, equal, or stronger in strength relative to the ubiquitous control promoter smCBA. All MiniPromoters will be useful for therapies involving small regulatory RNA and DNA, and proteins ranging from 517 to 1084 amino acids, representing 62.9-90.2% of human proteins.
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Affiliation(s)
- Andrea J. Korecki
- grid.17091.3e0000 0001 2288 9830Centre for Molecular Medicine and Therapeutics at BC Children’s Hospital, University of British Columbia, Vancouver, BC Canada
| | - Jorge L. Cueva-Vargas
- grid.14848.310000 0001 2292 3357Department of Neuroscience, University of Montreal Hospital Research Centre, University of Montreal, Montreal, QC Canada
| | - Oriol Fornes
- grid.17091.3e0000 0001 2288 9830Centre for Molecular Medicine and Therapeutics at BC Children’s Hospital, University of British Columbia, Vancouver, BC Canada
| | - Jessica Agostinone
- grid.14848.310000 0001 2292 3357Department of Neuroscience, University of Montreal Hospital Research Centre, University of Montreal, Montreal, QC Canada
| | - Rachelle A. Farkas
- grid.17091.3e0000 0001 2288 9830Centre for Molecular Medicine and Therapeutics at BC Children’s Hospital, University of British Columbia, Vancouver, BC Canada ,grid.17091.3e0000 0001 2288 9830Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
| | - Jack W. Hickmott
- grid.17091.3e0000 0001 2288 9830Centre for Molecular Medicine and Therapeutics at BC Children’s Hospital, University of British Columbia, Vancouver, BC Canada ,grid.17091.3e0000 0001 2288 9830Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
| | - Siu Ling Lam
- grid.17091.3e0000 0001 2288 9830Centre for Molecular Medicine and Therapeutics at BC Children’s Hospital, University of British Columbia, Vancouver, BC Canada
| | - Anthony Mathelier
- grid.17091.3e0000 0001 2288 9830Centre for Molecular Medicine and Therapeutics at BC Children’s Hospital, University of British Columbia, Vancouver, BC Canada
| | - Michelle Zhou
- grid.17091.3e0000 0001 2288 9830Centre for Molecular Medicine and Therapeutics at BC Children’s Hospital, University of British Columbia, Vancouver, BC Canada
| | - Wyeth W. Wasserman
- grid.17091.3e0000 0001 2288 9830Centre for Molecular Medicine and Therapeutics at BC Children’s Hospital, University of British Columbia, Vancouver, BC Canada ,grid.17091.3e0000 0001 2288 9830Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
| | - Adriana Di Polo
- grid.14848.310000 0001 2292 3357Department of Neuroscience, University of Montreal Hospital Research Centre, University of Montreal, Montreal, QC Canada
| | - Elizabeth M. Simpson
- grid.17091.3e0000 0001 2288 9830Centre for Molecular Medicine and Therapeutics at BC Children’s Hospital, University of British Columbia, Vancouver, BC Canada ,grid.17091.3e0000 0001 2288 9830Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
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Lankford CK, Laird JG, Inamdar SM, Baker SA. A Comparison of the Primary Sensory Neurons Used in Olfaction and Vision. Front Cell Neurosci 2020; 14:595523. [PMID: 33250719 PMCID: PMC7676898 DOI: 10.3389/fncel.2020.595523] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 10/06/2020] [Indexed: 12/18/2022] Open
Abstract
Vision, hearing, smell, taste, and touch are the tools used to perceive and navigate the world. They enable us to obtain essential resources such as food and highly desired resources such as mates. Thanks to the investments in biomedical research the molecular unpinning’s of human sensation are rivaled only by our knowledge of sensation in the laboratory mouse. Humans rely heavily on vision whereas mice use smell as their dominant sense. Both modalities have many features in common, starting with signal detection by highly specialized primary sensory neurons—rod and cone photoreceptors (PR) for vision, and olfactory sensory neurons (OSN) for the smell. In this chapter, we provide an overview of how these two types of primary sensory neurons operate while highlighting the similarities and distinctions.
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Affiliation(s)
- Colten K Lankford
- Department of Biochemistry, University of Iowa, Iowa City, IA, United States
| | - Joseph G Laird
- Department of Biochemistry, University of Iowa, Iowa City, IA, United States
| | - Shivangi M Inamdar
- Department of Biochemistry, University of Iowa, Iowa City, IA, United States
| | - Sheila A Baker
- Department of Biochemistry, University of Iowa, Iowa City, IA, United States.,Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, United States
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30
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Interplay between cell-adhesion molecules governs synaptic wiring of cone photoreceptors. Proc Natl Acad Sci U S A 2020; 117:23914-23924. [PMID: 32879010 DOI: 10.1073/pnas.2009940117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Establishment of functional synaptic connections in a selective manner is essential for nervous system operation. In mammalian retinas, rod and cone photoreceptors form selective synaptic connections with different classes of bipolar cells (BCs) to propagate light signals. While there has been progress in elucidating rod wiring, molecular mechanisms used by cones to establish functional synapses with BCs have remained unknown. Using an unbiased proteomic strategy in cone-dominant species, we identified the cell-adhesion molecule ELFN2 to be pivotal for the functional wiring of cones with the ON type of BC. It is selectively expressed in cones and transsynaptically recruits the key neurotransmitter receptor mGluR6 in ON-BCs to enable synaptic transmission. Remarkably, ELFN2 in cone terminals functions in synergy with a related adhesion molecule, ELFN1, and their concerted interplay during development specifies selective wiring and transmission of cone signals. These findings identify a synaptic connectivity mechanism of cones and illustrate how interplay between adhesion molecules and postsynaptic transmitter receptors orchestrates functional synaptic specification in a neural circuit.
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31
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Senapati S, Park PSH. Differential adaptations in rod outer segment disc membranes in different models of congenital stationary night blindness. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183396. [PMID: 32533975 DOI: 10.1016/j.bbamem.2020.183396] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/01/2020] [Accepted: 06/08/2020] [Indexed: 01/20/2023]
Abstract
Rod photoreceptor cells initiate scotopic vision when the light receptor rhodopsin absorbs a photon of light to initiate phototransduction. These photoreceptor cells are exquisitely sensitive and have adaptive mechanisms in place to maintain optimal function and to overcome dysfunctional states. One adaptation rod photoreceptor cells exhibit is in the packing properties of rhodopsin within the membrane. The mechanism underlying these adaptations is unclear. Mouse models of congenital stationary night blindness with different molecular causes were investigated to determine which signals are important for adaptations in rod photoreceptor cells. Night blindness in these mice is caused by dysfunction in either rod photoreceptor cell signaling or bipolar cell signaling. Changes in the packing of rhodopsin within photoreceptor cell membranes were examined by atomic force microscopy. Mice expressing constitutively active rhodopsin did not exhibit any adaptations, even under constant dark conditions. Mice with disrupted bipolar cell signaling exhibited adaptations, however, they were distinct from those in mice with disrupted phototransduction. These differential adaptations demonstrate that although multiple molecular defects can lead to a similar primary defect causing disease (i.e., night blindness), they can cause different secondary effects (i.e., adaptations). The lighting environment or signaling defects present from birth and during early rearing can condition mice and affect the adaptations occurring in more mature animals. A comparison of effects in wild-type mice, mice with defective phototransduction, and mice with defective bipolar cell signaling, indicated that bipolar cell signaling plays a role in this conditioning but is not required for adaptations in more mature animals.
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Affiliation(s)
- Subhadip Senapati
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA.
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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.
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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
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Empowering Retinal Gene Therapy with a Specific Promoter for Human Rod and Cone ON-Bipolar Cells. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 17:505-519. [PMID: 32258214 PMCID: PMC7114634 DOI: 10.1016/j.omtm.2020.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 03/09/2020] [Indexed: 12/31/2022]
Abstract
Optogenetic gene therapy holds promise to restore high-quality vision in blind patients and recently reached clinical trials. Although the ON-bipolar cells, the first retinal interneurons, make the most attractive targets for optogenetic vision restoration, they have remained inaccessible to human gene therapy due to the lack of a robust cell-specific promoter. We describe the design and functional evaluation of 770En_454P(hGRM6), a human GRM6 gene-derived, short promoter that drives strong and highly specific expression in both the rod- and cone-type ON-bipolar cells of the human retina. Expression also in cone-type ON-bipolar cells is of importance, since the cone-dominated macula mediates high-acuity vision and is the primary target of gene therapies. 770En_454P(hGRM6)-driven middle-wave opsin expression in ON-bipolar cells achieved lasting restoration of high visual acuity in the rd1 mouse model of late retinal degeneration. The new promoter enables precise manipulation of the inner retinal network and paves the way for clinical application of gene therapies for high-resolution optogenetic vision restoration, raising hopes of significantly improving the life quality of people suffering from blindness.
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Orlandi C, Omori Y, Wang Y, Cao Y, Ueno A, Roux MJ, Condomitti G, de Wit J, Kanagawa M, Furukawa T, Martemyanov KA. Transsynaptic Binding of Orphan Receptor GPR179 to Dystroglycan-Pikachurin Complex Is Essential for the Synaptic Organization of Photoreceptors. Cell Rep 2020; 25:130-145.e5. [PMID: 30282023 PMCID: PMC6203450 DOI: 10.1016/j.celrep.2018.08.068] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 08/16/2018] [Accepted: 08/23/2018] [Indexed: 01/05/2023] Open
Abstract
Establishing synaptic contacts between neurons is paramount for nervous system function. This process involves transsynaptic interactions between a host of cell adhesion molecules that act in cooperation with the proteins of the extracellular matrix to specify uniquephysiological propertiesofindividual synaptic connections. However, understanding of the molecular mechanisms that generate functional diversity in an input-specific fashion is limited. In this study, we identify that major components of the extracellular matrix proteins present in the synaptic cleft—members oftheheparansulfateproteoglycan (HSPG) family—associate with the GPR158/179 group of orphan receptors. Using the mammalian retina as a model system, we demonstrate that the HSPG member Pikachurin, released by photoreceptors, recruits a key post-synaptic signaling complex of downstream ON-bipolar neurons in coordination with the presynaptic dystroglycan glycoprotein complex. We further demonstrate that this transsynaptic assembly plays an essential role in synaptic transmission of photoreceptor signals. Orlandi et al. identify transsynaptic assembly at photoreceptor synapses involving pre-synaptic dystrophindystroglycan complex and the postsynaptic orphan receptor GPR179 bridged by HSPG protein Pikachurin in the cleft and demonstrate its role in shaping transmission of photoreceptor signals.
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Affiliation(s)
- Cesare Orlandi
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Yoshihiro Omori
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Yuchen Wang
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Yan Cao
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Akiko Ueno
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Michel J Roux
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Centre National de la Recherche Scientifique, UMR7104, INSERM, U1258, Illkirch, France
| | - Giuseppe Condomitti
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Herestraat 49, 3000 Leuven, Belgium
| | - Joris de Wit
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Herestraat 49, 3000 Leuven, Belgium
| | - Motoi Kanagawa
- Division of Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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Thoreson WB, Dacey DM. Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina. Physiol Rev 2019; 99:1527-1573. [PMID: 31140374 DOI: 10.1152/physrev.00027.2018] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Synaptic interactions to extract information about wavelength, and thus color, begin in the vertebrate retina with three classes of light-sensitive cells: rod photoreceptors at low light levels, multiple types of cone photoreceptors that vary in spectral sensitivity, and intrinsically photosensitive ganglion cells that contain the photopigment melanopsin. When isolated from its neighbors, a photoreceptor confounds photon flux with wavelength and so by itself provides no information about color. The retina has evolved elaborate color opponent circuitry for extracting wavelength information by comparing the activities of different photoreceptor types broadly tuned to different parts of the visible spectrum. We review studies concerning the circuit mechanisms mediating opponent interactions in a range of species, from tetrachromatic fish with diverse color opponent cell types to common dichromatic mammals where cone opponency is restricted to a subset of specialized circuits. Distinct among mammals, primates have reinvented trichromatic color vision using novel strategies to incorporate evolution of an additional photopigment gene into the foveal structure and circuitry that supports high-resolution vision. Color vision is absent at scotopic light levels when only rods are active, but rods interact with cone signals to influence color perception at mesopic light levels. Recent evidence suggests melanopsin-mediated signals, which have been identified as a substrate for setting circadian rhythms, may also influence color perception. We consider circuits that may mediate these interactions. While cone opponency is a relatively simple neural computation, it has been implemented in vertebrates by diverse neural mechanisms that are not yet fully understood.
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Affiliation(s)
- Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
| | - Dennis M Dacey
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
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Balancing the Photoreceptor Proteome: Proteostasis Network Therapeutics for Inherited Retinal Disease. Genes (Basel) 2019; 10:genes10080557. [PMID: 31344897 PMCID: PMC6722924 DOI: 10.3390/genes10080557] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/09/2019] [Accepted: 07/16/2019] [Indexed: 12/17/2022] Open
Abstract
The light sensing outer segments of photoreceptors (PRs) are renewed every ten days due to their high photoactivity, especially of the cones during daytime vision. This demands a tremendous amount of energy, as well as a high turnover of their main biosynthetic compounds, membranes, and proteins. Therefore, a refined proteostasis network (PN), regulating the protein balance, is crucial for PR viability. In many inherited retinal diseases (IRDs) this balance is disrupted leading to protein accumulation in the inner segment and eventually the death of PRs. Various studies have been focusing on therapeutically targeting the different branches of the PR PN to restore the protein balance and ultimately to treat inherited blindness. This review first describes the different branches of the PN in detail. Subsequently, insights are provided on how therapeutic compounds directed against the different PN branches might slow down or even arrest the appalling, progressive blinding conditions. These insights are supported by findings of PN modulators in other research disciplines.
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In Focus in HCB. Histochem Cell Biol 2019; 151:457-459. [PMID: 31111197 DOI: 10.1007/s00418-019-01788-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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38
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Okawa H, Yu WQ, Matti U, Schwarz K, Odermatt B, Zhong H, Tsukamoto Y, Lagnado L, Rieke F, Schmitz F, Wong ROL. Dynamic assembly of ribbon synapses and circuit maintenance in a vertebrate sensory system. Nat Commun 2019; 10:2167. [PMID: 31092821 PMCID: PMC6520400 DOI: 10.1038/s41467-019-10123-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 04/10/2019] [Indexed: 11/11/2022] Open
Abstract
Ribbon synapses transmit information in sensory systems, but their development is not well understood. To test the hypothesis that ribbon assembly stabilizes nascent synapses, we performed simultaneous time-lapse imaging of fluorescently-tagged ribbons in retinal cone bipolar cells (BCs) and postsynaptic densities (PSD95-FP) of retinal ganglion cells (RGCs). Ribbons and PSD95-FP clusters were more stable when these components colocalized at synapses. However, synapse density on ON-alpha RGCs was unchanged in mice lacking ribbons (ribeye knockout). Wildtype BCs make both ribbon-containing and ribbon-free synapses with these GCs even at maturity. Ribbon assembly and cone BC-RGC synapse maintenance are thus regulated independently. Despite the absence of synaptic ribbons, RGCs continued to respond robustly to light stimuli, although quantitative examination of the responses revealed reduced frequency and contrast sensitivity.
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Affiliation(s)
- Haruhisa Okawa
- Department of Biological Structure, University of Washington, Seattle, 98195, WA, USA
| | - Wan-Qing Yu
- Department of Biological Structure, University of Washington, Seattle, 98195, WA, USA
| | - Ulf Matti
- Department of Neuroanatomy, Medical School Homburg/Saar, Institute for Anatomy and Cell Biology, Saarland University, Homburg/Saar, 66421, Germany
| | - Karin Schwarz
- Department of Neuroanatomy, Medical School Homburg/Saar, Institute for Anatomy and Cell Biology, Saarland University, Homburg/Saar, 66421, Germany
| | | | - Haining Zhong
- Vollum institute, Oregon Health and Science University, Portland, 97239, OR, USA
| | - Yoshihiko Tsukamoto
- Department of Biology, Hyogo College of Medicine, Nishinomiya, 663-8501, Hyogo, Japan
| | - Leon Lagnado
- School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Fred Rieke
- Department of Physiology and Biophysics, University of Washington, Seattle, 98195, WA, USA
| | - Frank Schmitz
- Department of Neuroanatomy, Medical School Homburg/Saar, Institute for Anatomy and Cell Biology, Saarland University, Homburg/Saar, 66421, Germany
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, Seattle, 98195, WA, USA.
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Twenty-Seven Tamoxifen-Inducible iCre-Driver Mouse Strains for Eye and Brain, Including Seventeen Carrying a New Inducible-First Constitutive-Ready Allele. Genetics 2019; 211:1155-1177. [PMID: 30765420 PMCID: PMC6456315 DOI: 10.1534/genetics.119.301984] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 02/11/2019] [Indexed: 12/25/2022] Open
Abstract
To understand gene function, the cre/loxP conditional system is the most powerful available for temporal and spatial control of expression in mouse. However, the research community requires more cre recombinase expressing transgenic mouse strains (cre-drivers) that restrict expression to specific cell types. To address these problems, a high-throughput method for large-scale production that produces high-quality results is necessary. Further, endogenous promoters need to be chosen that drive cell type specific expression, or we need to further focus the expression by manipulating the promoter. Here we test the suitability of using knock-ins at the docking site 5′ of Hprt for rapid development of numerous cre-driver strains focused on expression in adulthood, using an improved cre tamoxifen inducible allele (icre/ERT2), and testing a novel inducible-first, constitutive-ready allele (icre/f3/ERT2/f3). In addition, we test two types of promoters either to capture an endogenous expression pattern (MaxiPromoters), or to restrict expression further using minimal promoter element(s) designed for expression in restricted cell types (MiniPromoters). We provide new cre-driver mouse strains with applicability for brain and eye research. In addition, we demonstrate the feasibility and applicability of using the locus 5′ of Hprt for the rapid generation of substantial numbers of cre-driver strains. We also provide a new inducible-first constitutive-ready allele to further speed cre-driver generation. Finally, all these strains are available to the research community through The Jackson Laboratory.
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Hoffman BU, Baba Y, Griffith TN, Mosharov EV, Woo SH, Roybal DD, Karsenty G, Patapoutian A, Sulzer D, Lumpkin EA. Merkel Cells Activate Sensory Neural Pathways through Adrenergic Synapses. Neuron 2018; 100:1401-1413.e6. [PMID: 30415995 DOI: 10.1016/j.neuron.2018.10.034] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/21/2018] [Accepted: 10/22/2018] [Indexed: 01/06/2023]
Abstract
Epithelial-neuronal signaling is essential for sensory encoding in touch, itch, and nociception; however, little is known about the release mechanisms and neurotransmitter receptors through which skin cells govern neuronal excitability. Merkel cells are mechanosensory epidermal cells that have long been proposed to activate neuronal afferents through chemical synaptic transmission. We employed a set of classical criteria for chemical neurotransmission as a framework to test this hypothesis. RNA sequencing of adult mouse Merkel cells demonstrated that they express presynaptic molecules and biosynthetic machinery for adrenergic transmission. Moreover, live-cell imaging directly demonstrated that Merkel cells mediate activity- and VMAT-dependent release of fluorescent catecholamine neurotransmitter analogs. Touch-evoked firing in Merkel-cell afferents was inhibited either by pre-synaptic silencing of SNARE-mediated vesicle release from Merkel cells or by neuronal deletion of β2-adrenergic receptors. Together, these results identify both pre- and postsynaptic mechanisms through which Merkel cells excite mechanosensory afferents to encode gentle touch. VIDEO ABSTRACT.
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Affiliation(s)
- Benjamin U Hoffman
- Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, USA; Program in Neurobiology & Behavior, Columbia University, New York, NY, USA
| | - Yoshichika Baba
- Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, USA
| | - Theanne N Griffith
- Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, USA
| | - Eugene V Mosharov
- Departments of Psychiatry, Neurology, and Pharmacology, Columbia University: Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Seung-Hyun Woo
- The Scripps Research Institute & Howard Hughes Medical Institute, La Jolla, CA, USA
| | - Daniel D Roybal
- Pharmacology Graduate Program, Columbia University, New York, NY, USA
| | - Gerard Karsenty
- Department of Genetics and Development, Columbia University, New York, NY, USA
| | - Ardem Patapoutian
- The Scripps Research Institute & Howard Hughes Medical Institute, La Jolla, CA, USA
| | - David Sulzer
- Departments of Psychiatry, Neurology, and Pharmacology, Columbia University: Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Ellen A Lumpkin
- Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, USA; Program in Neurobiology & Behavior, Columbia University, New York, NY, USA; Department of Dermatology, Columbia University, New York, NY, USA.
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41
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Hellmer CB, Clemons MR, Nawy S, Ichinose T. A group I metabotropic glutamate receptor controls synaptic gain between rods and rod bipolar cells in the mouse retina. Physiol Rep 2018; 6:e13885. [PMID: 30338673 PMCID: PMC6194217 DOI: 10.14814/phy2.13885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 09/10/2018] [Accepted: 09/16/2018] [Indexed: 11/24/2022] Open
Abstract
The canonical mGluR6-Trpm1 pathway that generates the sign-inverting signal between photoreceptors and ON bipolar cells has been well described. However, one type of ON bipolar cell, the rod bipolar cell (RBC), additionally is thought to express the group I mGluRs whose function is unknown. We examined the role of group I mGluRs in mouse RBCs and here provide evidence that it controls synaptic gain between rods and RBCs. In dark-adapted conditions, the mGluR1 antagonists LY367385 and (RS)-1-Aminoindan-1,5-dicarboxylic acid, but not the mGluR5 antagonist 2-Methyl-6-(phenylethynyl)pyridine hydrochloride reduced the light-evoked responses in RBCs indicating that mGluR1, but not mGluR5, serves to potentiate RBC responses. Perturbing the downstream phospholipase C (PLC)-protein kinase C (PKC) pathway by inhibiting PLC, tightly buffering intracellular Ca2+ , or preventing its release from intracellular stores reduced the synaptic potentiation by mGluR1. The effect of mGluR1 activation was dependent upon adaptation state, strongly increasing the synaptic gain in dark-, but not in light-adapted retinas, or in the presence of a moderate background light, consistent with the idea that mGluR1 activation requires light-dependent glutamate release from rods. Moreover, immunostaining revealed that protein kinase Cα (PKCα) is more strongly expressed in RBC dendrites in dark-adapted conditions, revealing an additional mechanism behind the loss of mGluR1 potentiation. In light-adapted conditions, exogenous activation of mGluR1 with the agonist 3,5-Dihydroxyphenylglycine increased the mGluR6 currents in some RBCs and decreased it in others, suggesting an additional action of mGluR1 that is unmasked in the light-adapted state. Elevating intracellular free Ca2+ , consistently resulted in a decrease in synaptic gain. Our results provide evidence that mGluR1 controls the synaptic gain in RBCs.
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Affiliation(s)
- Chase B. Hellmer
- Department of Ophthalmology, Visual and Anatomical SciencesWayne State University School of MedicineDetroitMichigan48201
| | - Melissa Rampino Clemons
- Dominic P Purpura Dept. of NeuroscienceAlbert Einstein College of Medicine BronxBronxNew York10461
| | - Scott Nawy
- Dominic P Purpura Dept. of NeuroscienceAlbert Einstein College of Medicine BronxBronxNew York10461
- Department of Ophthalmology and Visual SciencesUniversity of Nebraska Medical CenterOmahaNebraska68198
| | - Tomomi Ichinose
- Department of Ophthalmology, Visual and Anatomical SciencesWayne State University School of MedicineDetroitMichigan48201
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Vinberg F, Chen J, Kefalov VJ. Regulation of calcium homeostasis in the outer segments of rod and cone photoreceptors. Prog Retin Eye Res 2018; 67:87-101. [PMID: 29883715 DOI: 10.1016/j.preteyeres.2018.06.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/30/2018] [Accepted: 06/04/2018] [Indexed: 12/11/2022]
Abstract
Calcium plays important roles in the function and survival of rod and cone photoreceptor cells. Rapid regulation of calcium in the outer segments of photoreceptors is required for the modulation of phototransduction that drives the termination of the flash response as well as light adaptation in rods and cones. On a slower time scale, maintaining proper calcium homeostasis is critical for the health and survival of photoreceptors. Decades of work have established that the level of calcium in the outer segments of rods and cones is regulated by a dynamic equilibrium between influx via the transduction cGMP-gated channels and extrusion via rod- and cone-specific Na+/Ca2+, K+ exchangers (NCKXs). It had been widely accepted that the only mechanism for extrusion of calcium from rod outer segments is via the rod-specific NCKX1, while extrusion from cone outer segments is driven exclusively by the cone-specific NCKX2. However, recent evidence from mice lacking NCKX1 and NCKX2 have challenged that notion and have revealed a more complex picture, including a NCKX-independent mechanism in rods and two separate NCKX-dependent mechanisms in cones. This review will focus on recent findings on the molecular mechanisms of extrusion of calcium from the outer segments of rod and cone photoreceptors, and the functional and structural changes in photoreceptors when normal extrusion is disrupted.
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Affiliation(s)
- Frans Vinberg
- Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, USA; John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Jeannie Chen
- Zilkha Neurogenetic Institute, Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
| | - Vladimir J Kefalov
- Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, USA.
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43
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Agosto MA, Anastassov IA, Robichaux MA, Wensel TG. A Large Endoplasmic Reticulum-Resident Pool of TRPM1 in Retinal ON-Bipolar Cells. eNeuro 2018; 5:ENEURO.0143-18.2018. [PMID: 30027108 PMCID: PMC6051591 DOI: 10.1523/eneuro.0143-18.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 12/22/2022] Open
Abstract
The chemical signal of light onset, a decrease in glutamate release from rod and cone photoreceptors, is processed by a postsynaptic G protein signaling cascade in ON-bipolar cells (BPCs). The metabotropic glutamate receptor mGluR6, along with other cascade elements, is localized synaptically at the BPC dendritic tips. The effector ion channel protein transient receptor potential melastatin-1 (TRPM1), in contrast, is located not only at the dendritic tips but also in BPC bodies and axons. Little is known about the intracellular localization of TRPM1, or its trafficking route to the dendritic tip plasma membrane. Recombinant TRPM1 expressed in mammalian cells colocalized with endoplasmic reticulum (ER) markers, with little or none detected at the plasma membrane. In mouse retina, somatic TRPM1 was similarly intracellular, and not at the plasma membrane. Labeling of ER membranes by expression of a fluorescent marker showed that in BPCs the ER extends into axons and dendrites, but not dendritic tips. In cell bodies, TRPM1 colocalized with the ER, and not with the Golgi apparatus. Fluorescence protease protection (FPP) assays with TRPM1-GFP fusions in heterologous cells revealed that the N and C termini are both accessible to the cytoplasm, consistent with the transmembrane domain topology of related TRP channels. These results indicate that the majority of TRPM1 is present in the ER, from which it can potentially be transported to the dendritic tips as needed for ON light responses. The excess of ER-resident TRPM1 relative to the amount needed at the dendritic tips suggests a potential new function for TRPM1 in the ER.
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Affiliation(s)
- Melina A. Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Ivan A. Anastassov
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Michael A. Robichaux
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Theodore G. Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
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Sarria I, Cao Y, Wang Y, Ingram NT, Orlandi C, Kamasawa N, Kolesnikov AV, Pahlberg J, Kefalov VJ, Sampath AP, Martemyanov KA. LRIT1 Modulates Adaptive Changes in Synaptic Communication of Cone Photoreceptors. Cell Rep 2018; 22:3562-3573. [PMID: 29590623 PMCID: PMC5902029 DOI: 10.1016/j.celrep.2018.03.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/10/2018] [Accepted: 02/28/2018] [Indexed: 12/15/2022] Open
Abstract
Cone photoreceptors scale dynamically the sensitivity of responses to maintain responsiveness across wide range of changes in luminance. Synaptic changes contribute to this adaptation, but how this process is coordinated at the molecular level is poorly understood. Here, we report that a cell adhesion-like molecule, LRIT1, is enriched selectively at cone photoreceptor synapses where it engages in a trans-synaptic interaction with mGluR6, the principal receptor in postsynaptic ON-bipolar cells. The levels of LRIT1 are regulated by the neurotransmitter release apparatus that controls photoreceptor output. Knockout of LRIT1 in mice increases the sensitivity of cone synaptic signaling while impairing its ability to adapt to background light without overtly influencing the morphology or molecular composition of photoreceptor synapses. Accordingly, mice lacking LRIT1 show visual deficits under conditions requiring temporally challenging discrimination of visual signals in steady background light. These observations reveal molecular mechanisms involved in scaling synaptic communication in the retina.
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Affiliation(s)
- Ignacio Sarria
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Yan Cao
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Yuchen Wang
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Norianne T Ingram
- Department of Ophthalmology, Stein Eye Institute, UCLA School of Medicine, Los Angeles, CA 90095, USA
| | - Cesare Orlandi
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Naomi Kamasawa
- Electron Microscopy Core Facility, Max Planck Florida Institute, Jupiter, FL 33458, USA
| | - Alexander V Kolesnikov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Johan Pahlberg
- Department of Ophthalmology, Stein Eye Institute, UCLA School of Medicine, Los Angeles, CA 90095, USA
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alapakkam P Sampath
- Department of Ophthalmology, Stein Eye Institute, UCLA School of Medicine, Los Angeles, CA 90095, USA
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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