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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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Santhanam A, Shihabeddin E, Wei H, Wu J, O'Brien J. Molecular basis of retinal remodeling in a zebrafish model of retinitis pigmentosa. Cell Mol Life Sci 2023; 80:362. [PMID: 37979052 PMCID: PMC10657301 DOI: 10.1007/s00018-023-05021-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 10/10/2023] [Accepted: 10/27/2023] [Indexed: 11/19/2023]
Abstract
A hallmark of inherited retinal degenerative diseases such as retinitis pigmentosa (RP) is progressive structural and functional remodeling of the remaining retinal cells as photoreceptors degenerate. Extensive remodeling of the retina stands as a barrier for the successful implementation of strategies to restore vision. To understand the molecular basis of remodeling, we performed analyses of single-cell transcriptome data from adult zebrafish retina of wild type AB strain (WT) and a P23H mutant rhodopsin transgenic model of RP with continuous degeneration and regeneration. Retinas from both female and male fish were pooled to generate each library, combining data from both sexes. We provide a benchmark atlas of retinal cell type transcriptomes in zebrafish and insight into how each retinal cell type is affected in the P23H model. Oxidative stress is found throughout the retina, with increases in reliance on oxidative metabolism and glycolysis in the affected rods as well as cones, bipolar cells, and retinal ganglion cells. There is also transcriptional evidence for widespread synaptic remodeling and enhancement of glutamatergic transmission in the inner retina. Notably, changes in circadian rhythm regulation are detected in cones, bipolar cells, and retinal pigmented epithelium. We also identify the transcriptomic signatures of retinal progenitor cells and newly formed rods essential for the regenerative process. This comprehensive transcriptomic analysis provides a molecular road map to understand how the retina remodels in the context of chronic retinal degeneration with ongoing regeneration.
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Affiliation(s)
- Abirami Santhanam
- Department of Ophthalmology & Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
- University of Houston College of Optometry, Houston, TX, 77204, USA.
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Eyad Shihabeddin
- Department of Ophthalmology & Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
- MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
| | - Haichao Wei
- Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Jiaqian Wu
- MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
- Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - John O'Brien
- Department of Ophthalmology & Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
- University of Houston College of Optometry, Houston, TX, 77204, USA.
- MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, TX, 77030, USA.
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3
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Shrestha AP, Rameshkumar N, Boff JM, Rajmanna R, Chandrasegaran T, Frederick CE, Zenisek D, Vaithianathan T. The Effects of Aging on Rod Bipolar Cell Ribbon Synapses. Cells 2023; 12:2385. [PMID: 37830599 PMCID: PMC10572008 DOI: 10.3390/cells12192385] [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: 08/20/2023] [Revised: 09/20/2023] [Accepted: 09/27/2023] [Indexed: 10/14/2023] Open
Abstract
The global health concern posed by age-related visual impairment highlights the need for further research focused on the visual changes that occur during the process of aging. To date, multiple sensory alterations related to aging have been identified, including morphological and functional changes in inner hair cochlear cells, photoreceptors, and retinal ganglion cells. While some age-related morphological changes are known to occur in rod bipolar cells in the retina, their effects on these cells and on their connection to other cells via ribbon synapses remain elusive. To investigate the effects of aging on rod bipolar cells and their ribbon synapses, we compared synaptic calcium currents, calcium dynamics, and exocytosis in zebrafish (Danio rerio) that were middle-aged (MA,18 months) or old-aged (OA, 36 months). The bipolar cell terminal in OA zebrafish exhibited a two-fold reduction in number of synaptic ribbons, an increased ribbon length, and a decrease in local Ca2+ signals at the tested ribbon location, with little change in the overall magnitude of the calcium current or exocytosis in response to brief pulses. Staining of the synaptic ribbons with antibodies specific for PKCa revealed shortening of the inner nuclear and plexiform layers (INL and IPL). These findings shed light on age-related changes in the retina that are related to synaptic ribbons and calcium signals.
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Affiliation(s)
- Abhishek P. Shrestha
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Nirujan Rameshkumar
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Johane M. Boff
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Rhea Rajmanna
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | | | - Courtney E. Frederick
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA (D.Z.)
| | - David Zenisek
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA (D.Z.)
| | - 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, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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4
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Shukla D, Gural BM, Cauley ES, Battula N, Mowla S, Karas BF, Roberts LE, Cavallo L, Turkalj L, Moody SA, Swan LE, Manzini MC. Duplicated zebrafish (Danio rerio) inositol phosphatases inpp5ka and inpp5kb diverged in expression pattern and function. Dev Genes Evol 2023; 233:25-34. [PMID: 37184573 PMCID: PMC10239392 DOI: 10.1007/s00427-023-00703-z] [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: 08/31/2022] [Accepted: 04/27/2023] [Indexed: 05/16/2023]
Abstract
One hurdle in the development of zebrafish models of human disease is the presence of multiple zebrafish orthologs resulting from whole genome duplication in teleosts. Mutations in inositol polyphosphate 5-phosphatase K (INPP5K) lead to a syndrome characterized by variable presentation of intellectual disability, brain abnormalities, cataracts, muscle disease, and short stature. INPP5K is a phosphatase acting at position 5 of phosphoinositides to control their homeostasis and is involved in insulin signaling, cytoskeletal regulation, and protein trafficking. Previously, our group and others have replicated the human phenotypes in zebrafish knockdown models by targeting both INPP5K orthologs inpp5ka and inpp5kb. Here, we show that inpp5ka is the more closely related orthologue to human INPP5K. While both inpp5ka and inpp5kb mRNA expression levels follow a similar trend in the developing head, eyes, and tail, inpp5ka is much more abundantly expressed in these tissues than inpp5kb. In situ hybridization revealed a similar trend, also showing unique localization of inpp5kb in the pineal gland and retina indicating different transcriptional regulation. We also found that inpp5kb has lost its catalytic activity against its preferred substrate, PtdIns(4,5)P2. Since most human mutations are missense changes disrupting phosphatase activity, we propose that loss of inpp5ka alone can be targeted to recapitulate the human presentation. In addition, we show that the function of inpp5kb has diverged from inpp5ka and may play a novel role in the zebrafish.
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Affiliation(s)
- Dhyanam Shukla
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, 89 French Street, CHINJ Rm 3274, New Brunswick, NJ, 08901, USA
| | - Brian M Gural
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, 89 French Street, CHINJ Rm 3274, New Brunswick, NJ, 08901, USA
| | - Edmund S Cauley
- Department of Biochemistry and Molecular Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Namarata Battula
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, 89 French Street, CHINJ Rm 3274, New Brunswick, NJ, 08901, USA
| | - Shorbon Mowla
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, 89 French Street, CHINJ Rm 3274, New Brunswick, NJ, 08901, USA
| | - Brittany F Karas
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, 89 French Street, CHINJ Rm 3274, New Brunswick, NJ, 08901, USA
| | - Llion E Roberts
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Luca Cavallo
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, 89 French Street, CHINJ Rm 3274, New Brunswick, NJ, 08901, USA
| | - Luka Turkalj
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, 89 French Street, CHINJ Rm 3274, New Brunswick, NJ, 08901, USA
| | - Sally A Moody
- Department of Anatomy and Cell Biology, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Laura E Swan
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - M Chiara Manzini
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, 89 French Street, CHINJ Rm 3274, New Brunswick, NJ, 08901, USA.
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5
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Su H, Xie T, Liu YU, Cui Y, Wen W, Tang BZ, Qin W. Facile synthesis of ultrabright luminogens with specific lipid droplets targeting feature for in vivo two-photon fluorescence retina imaging. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.107949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Alba‐González A, Folgueira M, Castro A, Anadón R, Yáñez J. Distribution of neurogranin-like immunoreactivity in the brain and sensory organs of the adult zebrafish. J Comp Neurol 2022; 530:1569-1587. [PMID: 35015905 PMCID: PMC9415131 DOI: 10.1002/cne.25297] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 12/30/2021] [Accepted: 01/03/2022] [Indexed: 11/11/2022]
Abstract
We studied the expression of neurogranin in the brain and some sensory organs (barbel taste buds, olfactory organs, and retina) of adult zebrafish. Database analysis shows zebrafish has two paralog neurogranin genes (nrgna and nrgnb) that translate into three peptides with a conserved IQ domain, as in mammals. Western blots of zebrafish brain extracts using an anti-neurogranin antiserum revealed three separate bands, confirming the presence of three neurogranin peptides. Immunohistochemistry shows neurogranin-like expression in the brain and sensory organs (taste buds, neuromasts and olfactory epithelium), not being able to discern its three different peptides. In the retina, the most conspicuous positive cells were bipolar neurons. In the brain, immunopositive neurons were observed in all major regions (pallium, subpallium, preoptic area, hypothalamus, diencephalon, mesencephalon and rhombencephalon, including the cerebellum), a more extended distribution than in mammals. Interestingly, dendrites, cell bodies and axon terminals of some neurons were immunopositive, thus zebrafish neurogranins may play presynaptic and postsynaptic roles. Most positive neurons were found in primary sensory centers (viscerosensory column and medial octavolateral nucleus) and integrative centers (pallium, subpallium, optic tectum and cerebellum), which have complex synaptic circuitry. However, we also observed expression in areas not related to sensory or integrative functions, such as in cerebrospinal fluid-contacting cells associated with the hypothalamic recesses, which exhibited high neurogranin-like immunoreactivity. Together, these results reveal important differences with the patterns reported in mammals, suggesting divergent evolution from the common ancestor.
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Affiliation(s)
- Anabel Alba‐González
- Department of Biology, Faculty of SciencesUniversity of A CoruñaA CoruñaSpain,Centro de Investigaciones Científicas Avanzadas (CICA)University of A CoruñaA CoruñaSpain
| | - Mónica Folgueira
- Department of Biology, Faculty of SciencesUniversity of A CoruñaA CoruñaSpain,Centro de Investigaciones Científicas Avanzadas (CICA)University of A CoruñaA CoruñaSpain
| | - Antonio Castro
- Department of Biology, Faculty of SciencesUniversity of A CoruñaA CoruñaSpain,Centro de Investigaciones Científicas Avanzadas (CICA)University of A CoruñaA CoruñaSpain
| | - Ramón Anadón
- Department of Functional Biology, Faculty of BiologyUniversity of Santiago de CompostelaSantiago de CompostelaSpain
| | - Julián Yáñez
- Department of Biology, Faculty of SciencesUniversity of A CoruñaA CoruñaSpain,Centro de Investigaciones Científicas Avanzadas (CICA)University of A CoruñaA CoruñaSpain
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7
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Frederiksen R, Fain GL, Sampath AP. A hyperpolarizing rod bipolar cell in the sea lamprey, Petromyzon marinus. J Exp Biol 2022; 225:jeb243949. [PMID: 35319772 PMCID: PMC10658897 DOI: 10.1242/jeb.243949] [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: 12/29/2021] [Accepted: 03/15/2022] [Indexed: 11/20/2022]
Abstract
Retinal bipolar cells receive direct input from rod and cone photoreceptors and send axons into the inner retina, synapsing onto amacrine and ganglion cells. Bipolar cell responses can be either depolarizing (ON) or hyperpolarizing (OFF); in lower vertebrates, bipolar cells receive mixed rod and cone input, whereas in mammals, input is mostly segregated into 14 classes of cone ON and OFF cells and a single rod ON bipolar cell. We show that lamprey, like mammals, have rod bipolar cells with little or no cone input, but these cells are OFF rather than ON. They have a characteristic morphology and a spectral sensitivity nearly indistinguishable from that of rod photoreceptors. In background light known to saturate rods, rod bipolar cells are also saturated and cannot respond to increment flashes. Our results suggest that early vertebrate progenitors of both agnathans and gnathostomes may have had a more fluid retinal organization than previously thought.
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Affiliation(s)
- Rikard Frederiksen
- Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-7000, USA
| | - Gordon L. Fain
- Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-7000, USA
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095-7239, USA
| | - Alapakkam P. Sampath
- Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-7000, USA
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8
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Sharpe ZJ, Shehu A, Ichinose T. Asymmetric Distributions of Achromatic Bipolar Cells in the Mouse Retina. Front Neuroanat 2022; 15:786142. [PMID: 35095431 PMCID: PMC8792968 DOI: 10.3389/fnana.2021.786142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/13/2021] [Indexed: 11/23/2022] Open
Abstract
In the retina, evolutionary changes can be traced in the topography of photoreceptors. The shape of the visual streak depends on the height of the animal and its habitat, namely, woods, prairies, or mountains. Also, the distribution of distinct wavelength-sensitive cones is unique to each animal. For example, UV and green cones reside in the ventral and dorsal regions in the mouse retina, respectively, whereas in the rat retina these cones are homogeneously distributed. In contrast with the abundant investigation on the distribution of photoreceptors and the third-order neurons, the distribution of bipolar cells has not been well understood. We utilized two enhanced green fluorescent protein (EGFP) mouse lines, Lhx4-EGFP (Lhx4) and 6030405A18Rik-EGFP (Rik), to examine the topographic distributions of bipolar cells in the retina. First, we characterized their GFP-expressing cells using type-specific markers. We found that GFP was expressed by type 2, type 3a, and type 6 bipolar cells in the Rik mice and by type 3b, type 4, and type 5 bipolar cells in the Lhx4 mice. All these types are achromatic. Then, we examined the distributions of bipolar cells in the four cardinal directions and three different eccentricities of the retinal tissue. In the Rik mice, GFP-expressing bipolar cells were more highly observed in the nasal region than those in the temporal retina. The number of GFP cells was not different along with the ventral-dorsal axis. In contrast, in the Lhx4 mice, GFP-expressing cells occurred at a higher density in the ventral region than in the dorsal retina. However, no difference was observed along the nasal-temporal axis. Furthermore, we examined which type of bipolar cells contributed to the asymmetric distributions in the Rik mice. We found that type 3a bipolar cells occurred at a higher density in the temporal region, whereas type 6 bipolar cells were denser in the nasal region. The asymmetricity of these bipolar cells shaped the uneven distribution of the GFP cells in the Rik mice. In conclusion, we found that a subset of achromatic bipolar cells is asymmetrically distributed in the mouse retina, suggesting their unique roles in achromatic visual processing.
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Bartel P, Yoshimatsu T, Janiak FK, Baden T. Spectral inference reveals principal cone-integration rules of the zebrafish inner retina. Curr Biol 2021; 31:5214-5226.e4. [PMID: 34653362 PMCID: PMC8669161 DOI: 10.1016/j.cub.2021.09.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/09/2021] [Accepted: 09/17/2021] [Indexed: 01/05/2023]
Abstract
Retinal bipolar cells integrate cone signals at dendritic and axonal sites. The axonal route, involving amacrine cells, remains largely uncharted. However, because cone types differ in their spectral sensitivities, insights into bipolar cells' cone integration might be gained based on their spectral tunings. We therefore recorded in vivo responses of bipolar cell presynaptic terminals in larval zebrafish to widefield but spectrally resolved flashes of light and mapped the results onto spectral responses of the four cones. This "spectral circuit mapping" allowed explaining ∼95% of the spectral and temporal variance of bipolar cell responses in a simple linear model, thereby revealing several notable integration rules of the inner retina. Bipolar cells were dominated by red-cone inputs, often alongside equal sign inputs from blue and green cones. In contrast, UV-cone inputs were uncorrelated with those of the remaining cones. This led to a new axis of spectral opponency where red-, green-, and blue-cone "Off" circuits connect to "natively-On" UV-cone circuits in the outermost fraction of the inner plexiform layer-much as how key color opponent circuits are established in mammals. Beyond this, and despite substantial temporal diversity that was not present in the cones, bipolar cell spectral tunings were surprisingly simple. They either approximately resembled both opponent and non-opponent spectral motifs already present in the cones or exhibited a stereotyped non-opponent broadband response. In this way, bipolar cells not only preserved the efficient spectral representations in the cones but also diversified them to set up a total of six dominant spectral motifs, which included three axes of spectral opponency.
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Affiliation(s)
- Philipp Bartel
- School of Life Sciences, University of Sussex, Biology Road, BN1 9QG Brighton, UK
| | - Takeshi Yoshimatsu
- School of Life Sciences, University of Sussex, Biology Road, BN1 9QG Brighton, UK
| | - Filip K Janiak
- School of Life Sciences, University of Sussex, Biology Road, BN1 9QG Brighton, UK
| | - Tom Baden
- School of Life Sciences, University of Sussex, Biology Road, BN1 9QG Brighton, UK; Institute of Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076 Tübingen, Germany.
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Yoshimatsu T, Bartel P, Schröder C, Janiak FK, St-Pierre F, Berens P, Baden T. Ancestral circuits for vertebrate color vision emerge at the first retinal synapse. SCIENCE ADVANCES 2021; 7:eabj6815. [PMID: 34644120 PMCID: PMC8514090 DOI: 10.1126/sciadv.abj6815] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
For color vision, retinal circuits separate information about intensity and wavelength. In vertebrates that use the full complement of four “ancestral” cone types, the nature and implementation of this computation remain poorly understood. Here, we establish the complete circuit architecture of outer retinal circuits underlying color processing in larval zebrafish. We find that the synaptic outputs of red and green cones efficiently rotate the encoding of natural daylight in a principal components analysis–like manner to yield primary achromatic and spectrally opponent axes, respectively. Blue cones are tuned to capture most remaining variance when opposed to green cones, while UV cone present a UV achromatic axis for prey capture. We note that fruitflies use essentially the same strategy. Therefore, rotating color space into primary achromatic and chromatic axes at the eye’s first synapse may thus be a fundamental principle of color vision when using more than two spectrally well-separated photoreceptor types.
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Affiliation(s)
| | - Philipp Bartel
- School of Life Sciences, University of Sussex, Brighton, UK
| | - Cornelius Schröder
- Institute of Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | | | - François St-Pierre
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
- Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, USA
| | - Philipp Berens
- Institute of Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany
| | - Tom Baden
- School of Life Sciences, University of Sussex, Brighton, UK
- Institute of Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Corresponding author.
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Abstract
The use of spectral information in natural light to inform behaviour is one of the oldest and most fundamental abilities of visual systems. It long-predates animals' venture onto the land, and even the appearance of image-forming eyes. Accordingly, circuits for colour vision evolved under the surface of ancient oceans for hundreds of millions of years. These aquatic beginnings fundamentally underpin, and likely constrain, the organisation of modern visual systems. In contrast to our detailed circuit level understanding from diverse terrestrial vertebrates, however, comparatively little is known about their aquatic counterparts. Here, I summarise some of what is known about neural circuits for colour vision in fish, the most species-diverse group of vertebrates. With a focus on zebrafish, I will explore how their computational strategies are linked to the statistics of natural light in the underwater world, and how their study might help us understand vision in general, including in our own eyes.
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12
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Wang M, Du L, Lee AC, Li Y, Qin H, He J. Different lineage contexts direct common pro-neural factors to specify distinct retinal cell subtypes. J Cell Biol 2021; 219:151968. [PMID: 32699896 PMCID: PMC7480095 DOI: 10.1083/jcb.202003026] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 05/13/2020] [Accepted: 06/04/2020] [Indexed: 02/08/2023] Open
Abstract
How astounding neuronal diversity arises from variable cell lineages in vertebrates remains mostly elusive. By in vivo lineage tracing of ∼1,000 single zebrafish retinal progenitors, we identified a repertoire of subtype-specific stereotyped neurogenic lineages. Remarkably, within these stereotyped lineages, GABAergic amacrine cells were born with photoreceptor cells, whereas glycinergic amacrine cells were born with OFF bipolar cells. More interestingly, post-mitotic differentiation blockage of GABAergic and glycinergic amacrine cells resulted in their respecification into photoreceptor and bipolar cells, respectively, suggesting lineage constraint in cell subtype specification. Using single-cell RNA-seq and ATAC-seq analyses, we further identified lineage-specific progenitors, each defined by specific transcription factors that exhibited characteristic chromatin accessibility dynamics. Finally, single pro-neural factors could specify different neuron types/subtypes in a lineage-dependent manner. Our findings reveal the importance of lineage context in defining neuronal subtypes and provide a demonstration of in vivo lineage-dependent induction of unique retinal neuron subtypes for treatment purposes.
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Affiliation(s)
- Mei Wang
- State Key Laboratory of Neuroscience, Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
| | - Lei Du
- State Key Laboratory of Neuroscience, Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
| | - Aih Cheun Lee
- State Key Laboratory of Neuroscience, Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Yan Li
- State Key Laboratory of Neuroscience, Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
| | - Huiwen Qin
- State Key Laboratory of Neuroscience, Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
| | - Jie He
- State Key Laboratory of Neuroscience, Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
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13
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LeFauve MK, Rowe CJ, Crowley-Perry M, Wiegand JL, Shapiro AG, Connaughton VP. Using a variant of the optomotor response as a visual defect detection assay in zebrafish. J Biol Methods 2021; 8:e144. [PMID: 33604396 PMCID: PMC7884848 DOI: 10.14440/jbm.2021.341] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 12/10/2020] [Accepted: 12/10/2020] [Indexed: 11/23/2022] Open
Abstract
We describe a visual stimulus that can be used with both larval and adult zebrafish (Danio rerio). This protocol is a modification of a standard visual behavior analysis, the optomotor response (OMR). The OMR is often used to determine the spatial response or to detect directional visuomotor deficiencies. An OMR can be generated using a high contrast grated pattern, typically vertical bars. The spatial sensitivity is measured by detection and response to a change in grating bar width and is reported in cycles per degree (CPD). This test has been used extensively with zebrafish larvae and adults to identify visual- and/or motor-based mutations. Historically, when tested in adults, the grated pattern was presented from a vertical perspective, using a rotating cylinder around a holding tank, allowing the grating to be seen solely from the sides and front of the organism. In contrast, OMRs in zebrafish larvae are elicited using a stimulus projected below the fish. This difference in methodology means that two different experimental set-ups are required: one for adults and one for larvae. Our visual stimulus modifies the stimulation format so that a single OMR stimulus, suitable for use with both adults and larvae, is being presented underneath the fish. Analysis of visuomotor responses using this method does not require costly behavioral tracking software and, using a single behavioral paradigm, allows the observer to rapidly determine visual spatial response in both zebrafish larvae and adults.
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Affiliation(s)
- Matthew K LeFauve
- Department of Biological Sciences, George Washington University, 800 22 St NW, Washington, DC 20052, USA.,Department of Biology, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA
| | - Cassie J Rowe
- Department of Biology, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA.,Center for Behavioral Neuroscience, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA
| | - Mikayla Crowley-Perry
- Department of Biology, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA.,Department of Chemistry, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA
| | - Jenna L Wiegand
- Department of Biology, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA
| | - Arthur G Shapiro
- Center for Behavioral Neuroscience, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA.,Department of Psychology, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA.,Department of Computer Science, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA
| | - Victoria P Connaughton
- Department of Biology, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA.,Center for Behavioral Neuroscience, American University, 4400 Massachusetts Ave NW, Washington, DC 20016, USA
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14
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Controlling Horizontal Cell-Mediated Lateral Inhibition in Transgenic Zebrafish Retina with Chemogenetic Tools. eNeuro 2020; 7:ENEURO.0022-20.2020. [PMID: 33060180 PMCID: PMC7665903 DOI: 10.1523/eneuro.0022-20.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 08/11/2020] [Accepted: 08/28/2020] [Indexed: 12/03/2022] Open
Abstract
Horizontal cells (HCs) form reciprocal synapses with rod and cone photoreceptors, an arrangement that underlies lateral inhibition in the retina. HCs send negative and positive feedback signals to photoreceptors, but how HCs initiate these signals remains unclear. Unfortunately, because HCs have no unique neurotransmitter receptors, there are no pharmacological treatments for perturbing membrane potential specifically in HCs. Here we use transgenic zebrafish whose HCs express alien receptors, enabling cell-type-specific control by cognate alien agonists. To depolarize HCs, we used the Phe-Met-Arg-Phe-amide (FMRFamide)-gated Na+ channel (FaNaC) activated by the invertebrate neuropeptide FMRFamide. To hyperpolarize HCs we used a pharmacologically selective actuator module (PSAM)-glycine receptor (GlyR), an engineered Cl– selective channel activated by a synthetic agonist. Expression of FaNaC or PSAM-GlyR was restricted to HCs with the cell-type selective promoter for connexin-55.5. We assessed HC-feedback control of photoreceptor synapses in three ways. First, we measured presynaptic exocytosis from photoreceptor terminals using the fluorescent dye FM1-43. Second, we measured the electroretinogram (ERG) b-wave, a signal generated by postsynaptic responses. Third, we used Ca2+ imaging in retinal ganglion cells (RGCs) expressing the Ca2+ indicator GCaMP6. Addition of FMRFamide significantly decreased FM1-43 destaining in darkness, whereas the addition of PSAM-GlyR significantly increased it. However, both agonists decreased the light-elicited ERG b-wave and eliminated surround inhibition of the Ca2+ response of RGCs. Taken together, our findings show that chemogenetic tools can selectively manipulate negative feedback from HCs, providing a platform for understanding its mechanism and helping to elucidate its functional roles in visual information processing at a succession of downstream stages.
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15
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Cassar S, Dunn C, Ramos MF. Zebrafish as an Animal Model for Ocular Toxicity Testing: A Review of Ocular Anatomy and Functional Assays. Toxicol Pathol 2020; 49:438-454. [PMID: 33063651 DOI: 10.1177/0192623320964748] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Xenobiotics make their way into organisms from diverse sources including diet, medication, and pollution. Our understanding of ocular toxicities from xenobiotics in humans, livestock, and wildlife is growing thanks to laboratory animal models. Anatomy and physiology are conserved among vertebrate eyes, and studies with common mammalian preclinical species (rodent, dog) can predict human ocular toxicity. However, since the eye is susceptible to toxicities that may not involve a histological correlate, and these species rely heavily on smell and hearing to navigate their world, discovering visual deficits can be challenging with traditional animal models. Alternative models capable of identifying functional impacts on vision and requiring minimal amounts of chemical are valuable assets to toxicology. Human and zebrafish eyes are anatomically and functionally similar, and it has been reported that several common human ocular toxicants cause comparable toxicity in zebrafish. Vision develops rapidly in zebrafish; the tiny larvae rely on visual cues as early as 4 days, and behavioral responses to those cues can be monitored in high-throughput fashion. This article describes the comparative anatomy of the zebrafish eye, the notable differences from the mammalian eye, and presents practical applications of this underutilized model for assessment of ocular toxicity.
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Affiliation(s)
- Steven Cassar
- Preclinical Safety, 419726AbbVie, Inc, North Chicago, IL, USA
| | - Christina Dunn
- Preclinical Safety, 419726AbbVie, Inc, North Chicago, IL, USA
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16
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Abstract
Visual stimuli can evoke complex behavioral responses, but the underlying streams of neural activity in mammalian brains are difficult to follow because of their size. Here, I review the visual system of zebrafish larvae, highlighting where recent experimental evidence has localized the functional steps of visuomotor transformations to specific brain areas. The retina of a larva encodes behaviorally relevant visual information in neural activity distributed across feature-selective ganglion cells such that signals representing distinct stimulus properties arrive in different areas or layers of the brain. Motor centers in the hindbrain encode motor variables that are precisely tuned to behavioral needs within a given stimulus setting. Owing to rapid technological progress, larval zebrafish provide unique opportunities for obtaining a comprehensive understanding of the intermediate processing steps occurring between visual and motor centers, revealing how visuomotor transformations are implemented in a vertebrate brain.
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Affiliation(s)
- Johann H. Bollmann
- Developmental Biology, Institute of Biology I, Faculty of Biology, and Bernstein Center Freiburg, University of Freiburg, 79104 Freiburg, Germany
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17
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Haug MF, Berger M, Gesemann M, Neuhauss SCF. Differential expression of PKCα and -β in the zebrafish retina. Histochem Cell Biol 2019; 151:521-530. [PMID: 30604284 DOI: 10.1007/s00418-018-1764-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2018] [Indexed: 01/08/2023]
Abstract
The retina is a complex neural circuit, which processes and transmits visual information from light perceiving photoreceptors to projecting retinal ganglion cells. Much of the computational power of the retina rests on signal integrating interneurons, such as bipolar cells. Commercially available antibodies against bovine and human conventional protein kinase C (PKC) α and -β are frequently used as markers for retinal ON-bipolar cells in different species, despite the fact that it is not known which bipolar cell subtype(s) they actually label. In zebrafish (Danio rerio) five prkc genes (coding for PKC proteins) have been identified. Their expression has not been systematically determined. While prkcg is not expressed in retinal tissue, the other four prkc (prkcaa, prkcab, prkcba, prkcbb) transcripts were found in different parts of the inner nuclear layer and some as well in the retinal ganglion cell layer. Immunohistochemical analysis in adult zebrafish retina using fluorescent in situ hybridization and PKC antibodies showed an overlapping immunolabeling of ON-bipolar cells that are most likely of the BON s6 and BON s6L or RRod type. However, comparison of transcript expression with immunolabeling, implies that these antibodies are not specific for one single zebrafish conventional PKC, but rather detect a combination of PKC -α and -β variants.
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Affiliation(s)
- Marion F Haug
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Manuela Berger
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Matthias Gesemann
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Stephan C F Neuhauss
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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18
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Meier A, Nelson R, Connaughton VP. Color Processing in Zebrafish Retina. Front Cell Neurosci 2018; 12:327. [PMID: 30337857 PMCID: PMC6178926 DOI: 10.3389/fncel.2018.00327] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 09/10/2018] [Indexed: 11/13/2022] Open
Abstract
Zebrafish (Danio rerio) is a model organism for vertebrate developmental processes and, through a variety of mutant and transgenic lines, various diseases and their complications. Some of these diseases relate to proper function of the visual system. In the US, the National Eye Institute indicates >140 million people over the age of 40 have some form of visual impairment. The causes of the impairments range from refractive error to cataract, diabetic retinopathy and glaucoma, plus heritable diseases such as retinitis pigmentosa and color vision deficits. Most impairments directly affect the retina, the nervous tissue at the back of the eye. Zebrafish with long or short-wavelength color blindness, altered retinal anatomy due to hyperglycemia, high intraocular pressure, and reduced pigment epithelium are all used, and directly applicable, to study how these symptoms affect visual function. However, many published reports describe only molecular/anatomical/structural changes or behavioral deficits. Recent work in zebrafish has documented physiological responses of the different cell types to colored (spectral) light stimuli, indicating a complex level of information processing and color vision in this species. The purpose of this review article is to consolidate published morphological and physiological data from different cells to describe how zebrafish retina is capable of complex visual processing. This information is compared to findings in other vertebrates and relevance to disorders affecting color processing is discussed.
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Affiliation(s)
- April Meier
- Zebrafish Ecotoxicology, Neuropharmacology, and Vision Lab, Department of Biology, and Center for Behavioral Neuroscience, American University, Washington, DC, United States
| | - Ralph Nelson
- Neural Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), NIH, Bethesda, MD, United States
| | - Victoria P Connaughton
- Zebrafish Ecotoxicology, Neuropharmacology, and Vision Lab, Department of Biology, and Center for Behavioral Neuroscience, American University, Washington, DC, United States
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19
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Angueyra JM, Kindt KS. Leveraging Zebrafish to Study Retinal Degenerations. Front Cell Dev Biol 2018; 6:110. [PMID: 30283779 PMCID: PMC6156122 DOI: 10.3389/fcell.2018.00110] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 08/20/2018] [Indexed: 12/11/2022] Open
Abstract
Retinal degenerations are a heterogeneous group of diseases characterized by death of photoreceptors and progressive loss of vision. Retinal degenerations are a major cause of blindness in developed countries (Bourne et al., 2017; De Bode, 2017) and currently have no cure. In this review, we will briefly review the latest advances in therapies for retinal degenerations, highlighting the current barriers to study and develop therapies that promote photoreceptor regeneration in mammals. In light of these barriers, we present zebrafish as a powerful model to study photoreceptor regeneration and their integration into retinal circuits after regeneration. We outline why zebrafish is well suited for these analyses and summarize the powerful tools available in zebrafish that could be used to further uncover the mechanisms underlying photoreceptor regeneration and rewiring. In particular, we highlight that it is critical to understand how rewiring occurs after regeneration and how it differs from development. Insights derived from photoreceptor regeneration and rewiring in zebrafish may provide leverage to develop therapeutic targets to treat retinal degenerations.
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Affiliation(s)
- Juan M. Angueyra
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Katie S. Kindt
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
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20
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Restoration of Dendritic Complexity, Functional Connectivity, and Diversity of Regenerated Retinal Bipolar Neurons in Adult Zebrafish. J Neurosci 2017; 38:120-136. [PMID: 29133431 DOI: 10.1523/jneurosci.3444-16.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 10/27/2017] [Accepted: 11/03/2017] [Indexed: 12/29/2022] Open
Abstract
Adult zebrafish (Danio rerio) are capable of regenerating retinal neurons that have been lost due to mechanical, chemical, or light damage. In the case of chemical damage, there is evidence that visually mediated behaviors are restored after regeneration, consistent with recovery of retinal function. However, the extent to which regenerated retinal neurons attain appropriate morphologies and circuitry after such tissue-disrupting lesions has not been investigated. Adult zebrafish of both sexes were subjected to intravitreal injections of ouabain, which destroys the inner retina. After retinal regeneration, cell-selective markers, confocal microscopy, morphometrics, and electrophysiology were used to examine dendritic and axonal morphologies, connectivities, and the diversities of each, as well as retinal function, for a subpopulation of regenerated bipolar neurons (BPs). Although regenerated BPs were reduced in numbers, BP dendritic spreads, dendritic tree morphologies, and cone-bipolar connectivity patterns were restored in regenerated retinas, suggesting that regenerated BPs recover accurate input pathways from surviving cone photoreceptors. Morphological measurements of bipolar axons found that numbers and types of stratifications were also restored; however, the thickness of the inner plexiform layer and one measure of axon branching were slightly reduced after regeneration, suggesting some minor differences in the recovery of output pathways to downstream partners. Furthermore, ERG traces from regenerated retinas displayed waveforms matching those of controls, but with reduced b-wave amplitudes. These results support the hypothesis that regenerated neurons of the adult zebrafish retina are capable of restoring complex morphologies and circuitry, suggesting that complex visual functions may also be restored.SIGNIFICANCE STATEMENT Adult zebrafish generate new retinal neurons after a tissue-disrupting lesion. Existing research does not address whether regenerated neurons of adults successfully reconnect with surrounding neurons and establish complex morphologies and functions. We report that, after a chemical lesion that ablates inner retinal neurons, regenerated retinal bipolar neurons (BPs), although reduced in numbers, reconnected to undamaged cone photoreceptors with correct wiring patterns. Regenerated BPs had complex morphologies similar to those within undamaged retina and a physiological measure of photoreceptor-BP connectivity, the ERG, was restored to a normal waveform. This new understanding of neural connectivity, morphology, and physiology suggests that complex functional processing is possible within regenerated adult retina and offers a system for the future study of synaptogenesis during adult retinal regeneration.
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21
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Dudczig S, Currie PD, Jusuf PR. Developmental and adult characterization of secretagogin expressing amacrine cells in zebrafish retina. PLoS One 2017; 12:e0185107. [PMID: 28949993 PMCID: PMC5614429 DOI: 10.1371/journal.pone.0185107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 09/06/2017] [Indexed: 12/19/2022] Open
Abstract
Calcium binding proteins show stereotypical expression patterns within diverse neuron types across the central nervous system. Here, we provide a characterization of developmental and adult secretagogin-immunolabelled neurons in the zebrafish retina with an emphasis on co-expression of multiple calcium binding proteins. Secretagogin is a recently identified and cloned member of the F-hand family of calcium binding proteins, which labels distinct neuron populations in the retinas of mammalian vertebrates. Both the adult distribution of secretagogin labeled retinal neurons as well as the developmental expression indicative of the stage of neurogenesis during which this calcium binding protein is expressed was quantified. Secretagogin expression was confined to an amacrine interneuron population in the inner nuclear layer, with monostratified neurites in the center of the inner plexiform layer and a relatively regular soma distribution (regularity index > 2.5 across central–peripheral areas). However, only a subpopulation (~60%) co-labeled with gamma-aminobutyric acid as their neurotransmitter, suggesting that possibly two amacrine subtypes are secretagogin immunoreactive. Quantitative co-labeling analysis with other known amacrine subtype markers including the three main calcium binding proteins parvalbumin, calbindin and calretinin identifies secretagogin immunoreactive neurons as a distinct neuron population. The highest density of secretagogin cells of ~1800 cells / mm2 remained relatively evenly along the horizontal meridian, whilst the density dropped of to 125 cells / mm2 towards the dorsal and ventral periphery. Thus, secretagogin represents a new amacrine label within the zebrafish retina. The developmental expression suggests a possible role in late stage differentiation. This characterization forms the basis of functional studies assessing how the expression of distinct calcium binding proteins might be regulated to compensate for the loss of one of the others.
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Affiliation(s)
- Stefanie Dudczig
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
- School of Biosciences, University of Melbourne, Parkville, VIC, Australia
| | - Peter David Currie
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - Patricia Regina Jusuf
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
- School of Biosciences, University of Melbourne, Parkville, VIC, Australia
- * E-mail:
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22
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Abstract
The zebrafish (Danio rerio) possesses a vertebrate-type retina that is extraordinarily conserved in evolution. This well-organized and anatomically easily accessible part of the central nervous system has been widely investigated in zebrafish, promoting general understanding of retinal development, morphology, function and associated diseases. Over the recent years, genome and protein engineering as well as imaging techniques have experienced revolutionary advances and innovations, creating new possibilities and methods to study zebrafish development and function. In this review, we focus on some of these emerging technologies and how they may impact retinal research in the future. We place an emphasis on genetic techniques, such as transgenic approaches and the revolutionizing new possibilities in genome editing.
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Affiliation(s)
- Stephanie Niklaus
- a Institute of Molecular Life Sciences , University of Zurich , Zurich , Switzerland.,b Life Science Zurich Graduate Program - Neuroscience , Zurich , Switzerland
| | - Stephan C F Neuhauss
- a Institute of Molecular Life Sciences , University of Zurich , Zurich , Switzerland
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23
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Torvund MM, Ma TS, Connaughton VP, Ono F, Nelson RF. Cone signals in monostratified and bistratified amacrine cells of adult zebrafish retina. J Comp Neurol 2016; 525:1532-1557. [PMID: 27570913 DOI: 10.1002/cne.24107] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 08/17/2016] [Accepted: 08/24/2016] [Indexed: 11/10/2022]
Abstract
Strata within the inner plexiform layer (IPL) of vertebrate retinas are suspected to be distinct signaling regions. Functions performed within adult zebrafish IPL strata were examined through microelectrode recording and staining of stratified amacrine types. The stimulus protocol and analysis discriminated the pattern of input from red, green, blue, and UV cones as well as the light-response waveforms in this tetrachromatic species. A total of 36 cells were analyzed. Transient depolarizing waveforms at ON and OFF originated with bistratified amacrine types, whose dendritic planes branched either in IPL sublaminas a & b, or only within sublamina a. Monophasic-sustained depolarizing waveforms originated with types monostratified in IPL s4 (sublamina b). OFF responses hyperpolarized at onset, depolarized at offset, and in some cases depolarized during mid-stimulus. These signals originated with types monostratified in s1 or s2 (sublamina a). Bistratified amacrines received depolarizing signals only from red cones, at both ON and OFF, while s4 stratified ON cells combined red and green cone signals. The s1/s2 stratified OFF cells utilized hyperpolarizing signals from red, red and green, or red and blue cones at ON, but only depolarizing red cone signals at OFF. ON and OFF depolarizing transients from red cones appear widely distributed within IPL strata. "C-type" physiologies, depolarized by some wavelengths, hyperpolarized by others, in biphasic or triphasic spectral patterns, originated with amacrine cells monostratified in s5. Collectively, cells in this stratum processed signals from all cone types. J. Comp. Neurol. 525:1532-1557, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- M M Torvund
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rockville Maryland, 20892.,Graduate Program in Neuroscience, University of Arizona, Tucson, Arizona, 85421
| | - T S Ma
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rockville Maryland, 20892.,University of Pennsylvania, Department of Neurosurgery, Philadelphia, PA, 19104
| | - V P Connaughton
- Biology Department, American University, Washington, DC, 20016
| | - F Ono
- National Institute of Alcoholism and Alcohol Abuse, National Institutes of Health, Rockville, Maryland, 20892.,Department of Physiology, Osaka Medical College, Takatsuki, Japan, 569-8686
| | - R F Nelson
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rockville Maryland, 20892
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24
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Sukeena JM, Galicia CA, Wilson JD, McGinn T, Boughman JW, Robison BD, Postlethwait JH, Braasch I, Stenkamp DL, Fuerst PG. Characterization and Evolution of the Spotted Gar Retina. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 326:403-421. [PMID: 27862951 DOI: 10.1002/jez.b.22710] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/22/2016] [Accepted: 09/24/2016] [Indexed: 12/17/2022]
Abstract
In this study, we characterize the retina of the spotted gar, Lepisosteus oculatus, a ray-finned fish. Gar did not undergo the whole genome duplication event that occurred at the base of the teleost fish lineage, which includes the model species zebrafish and medaka. The divergence of gars from the teleost lineage and the availability of a high-quality genome sequence make it a uniquely useful species to understand how genome duplication sculpted features of the teleost visual system, including photoreceptor diversity. We developed reagents to characterize the cellular organization of the spotted gar retina, including representative markers for all major classes of retinal neurons and Müller glia. We report that the gar has a preponderance of predicted short-wavelength shifted (SWS) opsin genes, including a duplicated set of SWS1 (ultraviolet) sensitive opsin encoding genes, a SWS2 (blue) opsin encoding gene, and two rod opsin encoding genes, all of which were expressed in retinal photoreceptors. We also report that gar SWS1 cones lack the geometric organization of photoreceptors observed in teleost fish species, consistent with the crystalline photoreceptor mosaic being a teleost innovation. Of note the spotted gar expresses both exo-rhodopsin (RH1-1) and rhodopsin (RH1-2) in rods. Exo-rhodopsin is an opsin that is not expressed in the retina of zebrafish and other teleosts, but rather is expressed in regions of the brain. This study suggests that exo-rhodopsin is an ancestral actinopterygian (ray finned fish) retinal opsin, and in teleosts its expression has possibly been subfunctionalized to the pineal gland.
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Affiliation(s)
- Joshua M Sukeena
- Department of Biological Sciences, University of Idaho, Moscow, Idaho
| | - Carlos A Galicia
- Department of Biological Sciences, University of Idaho, Moscow, Idaho
| | | | - Tim McGinn
- Department of Biological Sciences, University of Idaho, Moscow, Idaho
| | - Janette W Boughman
- Department of Integrative Biology and Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, Michigan
| | - Barrie D Robison
- Department of Biological Sciences, University of Idaho, Moscow, Idaho
| | - John H Postlethwait
- Department of Evolution, Development, and Genetics, University of Oregon, Eugene, Oregon
| | - Ingo Braasch
- Department of Integrative Biology and Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, Michigan
| | | | - Peter G Fuerst
- Department of Biological Sciences, University of Idaho, Moscow, Idaho.,WWAMI Medical Education Program, University of Washington School of Medicine, Moscow, Idaho
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25
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Klaassen LJ, de Graaff W, van Asselt JB, Klooster J, Kamermans M. Specific connectivity between photoreceptors and horizontal cells in the zebrafish retina. J Neurophysiol 2016; 116:2799-2814. [PMID: 27707811 DOI: 10.1152/jn.00449.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/30/2016] [Indexed: 11/22/2022] Open
Abstract
The functional and morphological connectivity between various horizontal cell (HC) types (H1, H2, H3, and H4) and photoreceptors was studied in zebrafish retina. Since HCs are strongly coupled by gap junctions and feedback from HCs to photoreceptors depends strongly on connexin (Cx) hemichannels, we characterized the various HC Cxs (Cx52.6, Cx52.7, Cx52.9, and Cx55.5) in Xenopus oocytes. All Cxs formed hemichannels that were conducting at physiological membrane potentials. The Cx hemichannels differed in kinetic properties and voltage dependence, allowing for specific tuning of the coupling of HCs and the feedback signal from HCs to cones. The morphological connectivity between HC layers and cones was determined next. We used zebrafish expressing green fluorescent protein under the control of Cx promoters. We found that all HCs showed Cx55.5 promoter activity. Cx52.7 promoter activity was exclusively present in H4 cells, while Cx52.9 promoter activity occurred only in H1 cells. Cx52.6 promoter activity was present in H4 cells and in the ventral quadrant of the retina also in H1 cells. Finally, we determined the spectral sensitivities of the HC layers. Three response types were found. Monophasic responses were generated by HCs that contacted all cones (H1 cells), biphasic responses were generated by HCs that contacted M, S, and UV cones (H2 cells), and triphasic responses were generated by HCs that contacted either S and UV cones (H3 cells) or rods and UV cones (H4 cells). Electron microscopy confirms that H4 cells innervate cones. This indicates that rod-driven HCs process spectral information during photopic and luminance information during scotopic conditions.
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Affiliation(s)
- Lauw J Klaassen
- Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands; and
| | - Wim de Graaff
- Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands; and
| | - Jorrit B van Asselt
- Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands; and
| | - Jan Klooster
- Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands; and
| | - Maarten Kamermans
- Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands; and .,Department of Genome Analysis, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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26
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Boije H, Shirazi Fard S, Edqvist PH, Hallböök F. Horizontal Cells, the Odd Ones Out in the Retina, Give Insights into Development and Disease. Front Neuroanat 2016; 10:77. [PMID: 27486389 PMCID: PMC4949263 DOI: 10.3389/fnana.2016.00077] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/21/2016] [Indexed: 01/03/2023] Open
Abstract
Thorough investigation of a neuronal population can help reveal key aspects regarding the nervous system and its development. The retinal horizontal cells have several extraordinary features making them particularly interesting for addressing questions regarding fate assignment and subtype specification. In this review we discuss and summarize data concerning the formation and diversity of horizontal cells, how morphology is correlated to molecular markers, and how fate assignment separates the horizontal lineage from the lineages of other retinal cell types. We discuss the novel and unique features of the final cell cycle of horizontal cell progenitors and how they may relate to retinoblastoma carcinogenesis.
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Affiliation(s)
- Henrik Boije
- Department of Neuroscience, Uppsala University Uppsala, Sweden
| | | | - Per-Henrik Edqvist
- Department of Immunology, Genetics and Pathology, Uppsala University Uppsala, Sweden
| | - Finn Hallböök
- Department of Neuroscience, Uppsala University Uppsala, Sweden
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27
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Glasauer SMK, Wäger R, Gesemann M, Neuhauss SCF. mglur6b:EGFP Transgenic zebrafish suggest novel functions of metabotropic glutamate signaling in retina and other brain regions. J Comp Neurol 2016; 524:2363-78. [PMID: 27121676 DOI: 10.1002/cne.24029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/21/2016] [Accepted: 04/21/2016] [Indexed: 02/04/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are mainly known for regulating excitability of neurons. However, mGluR6 at the photoreceptor-ON bipolar cell synapse mediates sign inversion through glutamatergic inhibition. Although this is currently the only confirmed function of mGluR6, other functions have been suggested. Here we present Tg(mglur6b:EGFP)zh1, a new transgenic zebrafish line recapitulating endogenous expression of one of the two mglur6 paralogs in zebrafish. Investigating transgene as well as endogenous mglur6b expression within the zebrafish retina indicates that EGFP and mglur6b mRNA are not only expressed in bipolar cells, but also in a subset of ganglion and amacrine cells. The amacrine cells labeled in Tg(mglur6b:EGFP)zh1 constitute a novel cholinergic, non-GABAergic, non-starburst amacrine cell type described for the first time in teleost fishes. Apart from the retina, we found transgene expression in subsets of periventricular neurons of the hypothalamus, Purkinje cells of the cerebellum, various cell types of the optic tectum, and mitral/ruffed cells of the olfactory bulb. These findings suggest novel functions of mGluR6 besides sign inversion at ON bipolar cell dendrites, opening up the possibility that inhibitory glutamatergic signaling may be more prevalent than currently thought. J. Comp. Neurol. 524:2363-2378, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Stella M K Glasauer
- University of Zurich, Institute of Molecular Life Sciences, Zurich, Switzerland.,Life Science Zurich Graduate School, Ph.D. Program in Molecular Life Sciences, Zurich, Switzerland
| | - Robert Wäger
- University of Zurich, Institute of Molecular Life Sciences, Zurich, Switzerland
| | - Matthias Gesemann
- University of Zurich, Institute of Molecular Life Sciences, Zurich, Switzerland
| | - Stephan C F Neuhauss
- University of Zurich, Institute of Molecular Life Sciences, Zurich, Switzerland.,Life Science Zurich Graduate School, Ph.D. Program in Molecular Life Sciences, Zurich, Switzerland
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28
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Rosa JM, Ruehle S, Ding H, Lagnado L. Crossover Inhibition Generates Sustained Visual Responses in the Inner Retina. Neuron 2016; 90:308-19. [PMID: 27068790 PMCID: PMC4848346 DOI: 10.1016/j.neuron.2016.03.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 01/21/2016] [Accepted: 03/02/2016] [Indexed: 12/23/2022]
Abstract
In daylight, the input to the retinal circuit is provided primarily by cone photoreceptors acting as band-pass filters, but the retinal output also contains neuronal populations transmitting sustained signals. Using in vivo imaging of genetically encoded calcium reporters, we investigated the circuits that generate these sustained channels within the inner retina of zebrafish. In OFF bipolar cells, sustained transmission was found to depend on crossover inhibition from the ON pathway through GABAergic amacrine cells. In ON bipolar cells, the amplitude of low-frequency signals was regulated by glycinergic amacrine cells, while GABAergic inhibition regulated the gain of band-pass signals. We also provide the first functional description of a subset of sustained ON bipolar cells in which synaptic activity was suppressed by fluctuations at frequencies above ∼0.2 Hz. These results map out the basic circuitry by which the inner retina generates sustained visual signals and describes a new function of crossover inhibition.
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Affiliation(s)
- Juliana M Rosa
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Sabine Ruehle
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Huayu Ding
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Leon Lagnado
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK; School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK.
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29
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Kim MH, von Gersdorff H. Postsynaptic Plasticity Triggered by Ca²⁺-Permeable AMPA Receptor Activation in Retinal Amacrine Cells. Neuron 2016; 89:507-20. [PMID: 26804991 DOI: 10.1016/j.neuron.2015.12.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/18/2015] [Accepted: 12/15/2015] [Indexed: 01/04/2023]
Abstract
Amacrine cells are thought to be a major locus for mechanisms of light adaptation and contrast enhancement in the retina. However, the potential for plasticity in their AMPA receptor currents remains largely unknown. Using paired patch-clamp recordings between bipolar cell terminals and amacrine cells, we have simultaneously measured presynaptic membrane capacitance changes and EPSCs. Repetitive bipolar cell depolarizations, designed to maintain the same amount of exocytosis, nevertheless significantly potentiated evoked EPSCs in a subpopulation of amacrine cells. Likewise, repetitive iontophoresis (or puffs) of glutamate (or AMPA) onto the dendrites of amacrine cells also significantly potentiated evoked currents and [Ca(2+)]i rises. However, strong postsynaptic Ca(2+) buffering with BAPTA abolished the potentiation and selective antagonists of Ca(2+)-permeable AMPA receptors also blocked the potentiation of AMPA-mediated currents. Together these results suggest that Ca(2+) influx via Ca(2+)-permeable AMPA receptors can elicit a rapid form of postsynaptic plasticity in a subgroup of amacrine cell dendrites.
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Affiliation(s)
- Mean-Hwan Kim
- The Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Henrique von Gersdorff
- The Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA; Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA; Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239, USA.
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30
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Abstract
The first synapses transmitting visual information contain an unusual organelle, the ribbon, which is involved in the transport and priming of vesicles to be released at the active zone. The ribbon is one of many design features that allow efficient refilling of the active zone, which in turn enables graded changes in membrane potential to be transmitted using a continuous mode of neurotransmitter release. The ribbon also plays a key role in supplying vesicles for rapid and transient bursts of release that signal fast changes, such as the onset of light. We increasingly understand how the physiological properties of ribbon synapses determine basic transformations of the visual signal and, in particular, how the process of refilling the active zone regulates the gain and adaptive properties of the retinal circuit. The molecular basis of ribbon function is, however, far from clear.
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Affiliation(s)
- Leon Lagnado
- School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom;
| | - Frank Schmitz
- Department of Neuroanatomy, Institute for Anatomy and Cell Biology, Medical School Saarland University, Homburg/Saar, Germany;
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31
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Abstract
The mammalian retina is an important model system for studying neural circuitry: Its role in sensation is clear, its cell types are relatively well defined, and its responses to natural stimuli-light patterns-can be studied in vitro. To solve the retina, we need to understand how the circuits presynaptic to its output neurons, ganglion cells, divide the visual scene into parallel representations to be assembled and interpreted by the brain. This requires identifying the component interneurons and understanding how their intrinsic properties and synapses generate circuit behaviors. Because the cellular composition and fundamental properties of the retina are shared across species, basic mechanisms studied in the genetically modifiable mouse retina apply to primate vision. We propose that the apparent complexity of retinal computation derives from a straightforward mechanism-a dynamic balance of synaptic excitation and inhibition regulated by use-dependent synaptic depression-applied differentially to the parallel pathways that feed ganglion cells.
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Affiliation(s)
- Jonathan B Demb
- Department of Ophthalmology and Visual Science and Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut 06511;
| | - Joshua H Singer
- Department of Biology, University of Maryland, College Park, Maryland 20742;
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32
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Hunter PR, Hendry AC, Lowe AS. Zebrafish brain mapping-standardized spaces, length scales, and the power ofNandn. Dev Neurobiol 2014; 75:557-68. [DOI: 10.1002/dneu.22248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/14/2014] [Accepted: 11/21/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Paul R. Hunter
- MRC Centre for Developmental Neurobiology; King's College London, Guy's Hospital Campus; London SE1 1UL United Kingdom
| | - Aenea C. Hendry
- MRC Centre for Developmental Neurobiology; King's College London, Guy's Hospital Campus; London SE1 1UL United Kingdom
| | - Andrew S. Lowe
- MRC Centre for Developmental Neurobiology; King's College London, Guy's Hospital Campus; London SE1 1UL United Kingdom
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33
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A synaptic mechanism for temporal filtering of visual signals. PLoS Biol 2014; 12:e1001972. [PMID: 25333637 PMCID: PMC4205119 DOI: 10.1371/journal.pbio.1001972] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/10/2014] [Indexed: 12/22/2022] Open
Abstract
The visual system transmits information about fast and slow changes in light intensity through separate neural pathways. We used in vivo imaging to investigate how bipolar cells transmit these signals to the inner retina. We found that the volume of the synaptic terminal is an intrinsic property that contributes to different temporal filters. Individual cells transmit through multiple terminals varying in size, but smaller terminals generate faster and larger calcium transients to trigger vesicle release with higher initial gain, followed by more profound adaptation. Smaller terminals transmitted higher stimulus frequencies more effectively. Modeling global calcium dynamics triggering vesicle release indicated that variations in the volume of presynaptic compartments contribute directly to all these differences in response dynamics. These results indicate how one neuron can transmit different temporal components in the visual signal through synaptic terminals of varying geometries with different adaptational properties.
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34
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35
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Francke M, Kreysing M, Mack A, Engelmann J, Karl A, Makarov F, Guck J, Kolle M, Wolburg H, Pusch R, von der Emde G, Schuster S, Wagner HJ, Reichenbach A. Grouped retinae and tapetal cups in some Teleostian fish: Occurrence, structure, and function. Prog Retin Eye Res 2014; 38:43-69. [DOI: 10.1016/j.preteyeres.2013.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/01/2013] [Accepted: 10/02/2013] [Indexed: 11/27/2022]
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36
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Baier H. Synaptic laminae in the visual system: molecular mechanisms forming layers of perception. Annu Rev Cell Dev Biol 2013; 29:385-416. [PMID: 24099086 DOI: 10.1146/annurev-cellbio-101011-155748] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Synaptic connections between neurons form the basis for perception and behavior. Synapses are often clustered in space, forming stereotyped layers. In the retina and optic tectum, multiple such synaptic laminae are stacked on top of each other, giving rise to stratified neuropil regions in which each layer combines synapses responsive to a particular sensory feature. Recently, several cellular and molecular mechanisms that underlie the development of multilaminar arrays of synapses have been discovered. These mechanisms include neurite guidance and cell-cell recognition. Molecules of the Slit, Semaphorin, Netrin, and Hedgehog families, binding to their matching receptors, bring axons and dendrites into spatial register. These guidance cues may diffuse over short distances or bind to sheets of extracellular matrix, thus conditioning the local extracellular milieu, or are presented on the surface of cells bordering the future neuropil. In addition, mutual recognition of axons and dendrites through adhesion molecules with immunoglobulin domains ensures cell type-specific connections within a given layer. Thus, an elaborate genetic program assembles the parallel processing channels that underlie visual perception.
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Affiliation(s)
- Herwig Baier
- Genes - Circuits - Behavior, Max Planck Institute of Neurobiology, 82152 Martinsried near Munich, Germany;
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37
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Characterization of light lesion paradigms and optical coherence tomography as tools to study adult retina regeneration in zebrafish. PLoS One 2013; 8:e80483. [PMID: 24303018 PMCID: PMC3841302 DOI: 10.1371/journal.pone.0080483] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 10/13/2013] [Indexed: 11/19/2022] Open
Abstract
Light-induced lesions are a powerful tool to study the amazing ability of photoreceptors to regenerate in the adult zebrafish retina. However, the specificity of the lesion towards photoreceptors or regional differences within the retina are still incompletely understood. We therefore characterized the process of degeneration and regeneration in an established paradigm, using intense white light from a fluorescence lamp on swimming fish (diffuse light lesion). We also designed a new light lesion paradigm where light is focused through a microscope onto the retina of an immobilized fish (focused light lesion). Focused light lesion has the advantage of creating a locally restricted area of damage, with the additional benefit of an untreated control eye in the same animal. In both paradigms, cell death is observed as an immediate early response, and proliferation is initiated around 2 days post lesion (dpl), peaking at 3 dpl. We furthermore find that two photoreceptor subtypes (UV and blue sensitive cones) are more susceptible towards intense white light than red/green double cones and rods. We also observed specific differences within light lesioned areas with respect to the process of photoreceptor degeneration: UV cone debris is removed later than any other type of photoreceptor in light lesions. Unspecific damage to retinal neurons occurs at the center of a focused light lesion territory, but not in the diffuse light lesion areas. We simulated the fish eye optical properties using software simulation, and show that the optical properties may explain the light lesion patterns that we observe. Furthermore, as a new tool to study retinal degeneration and regeneration in individual fish in vivo, we use spectral domain optical coherence tomography. Collectively, the light lesion and imaging assays described here represent powerful tools for studying degeneration and regeneration processes in the adult zebrafish retina.
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38
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Nikolaev A, Leung KM, Odermatt B, Lagnado L. Synaptic mechanisms of adaptation and sensitization in the retina. Nat Neurosci 2013; 16:934-41. [PMID: 23685718 PMCID: PMC3924174 DOI: 10.1038/nn.3408] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/24/2013] [Indexed: 12/30/2022]
Abstract
Sensory systems continually adjust the way stimuli are processed. What are the circuit mechanisms underlying this plasticity? We investigated how synapses in the retina of zebrafish adjust to changes in the temporal contrast of a visual stimulus by imaging activity in vivo. Following an increase in contrast, bipolar cell synapses with strong initial responses depressed, whereas synapses with weak initial responses facilitated. Depression and facilitation predominated in different strata of the inner retina, where bipolar cell output was anticorrelated with the activity of amacrine cell synapses providing inhibitory feedback. Pharmacological block of GABAergic feedback converted facilitating bipolar cell synapses into depressing ones. These results indicate that depression intrinsic to bipolar cell synapses causes adaptation of the ganglion cell response to contrast, whereas depression in amacrine cell synapses causes sensitization. Distinct microcircuits segregating to different layers of the retina can cause simultaneous increases or decreases in the gain of neural responses.
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Affiliation(s)
- Anton Nikolaev
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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39
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Campbell PD, Marlow FL. Temporal and tissue specific gene expression patterns of the zebrafish kinesin-1 heavy chain family, kif5s, during development. Gene Expr Patterns 2013; 13:271-9. [PMID: 23684767 DOI: 10.1016/j.gep.2013.05.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 05/01/2013] [Accepted: 05/04/2013] [Indexed: 12/25/2022]
Abstract
Homo- and heterodimers of Kif5 proteins form the motor domain of Kinesin-1, a major plus-end directed microtubule motor. Kif5s have been implicated in the intracellular transport of organelles, vesicles, proteins, and RNAs in many cell types. There are three mammalian KIF5s. KIF5A and KIF5C proteins are strictly neural in mouse whereas, KIF5B is ubiquitously expressed. Mouse knockouts indicate crucial roles for KIF5 in development and human mutations in KIF5A lead to the neurodegenerative disease Hereditary Spastic Paraplegia. However, the developmental functions and the extent to which individual kif5 functions overlap have not been elucidated. Zebrafish possess five kif5 genes: kif5Aa, kif5Ab, kif5Ba, kif5Bb, and kif5C. Here we report their tissue specific expression patterns in embryonic and larval stages. Specifically, we find that kif5As are strictly zygotic and exhibit neural-specific expression. In contrast, kif5Bs exhibit strong maternal contribution and are ubiquitously expressed. Lastly, kif5C exhibits weak maternal expression followed by enrichment in neural populations. In addition, kif5s show distinct expression domains in the larval retina.
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Affiliation(s)
- Philip D Campbell
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
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40
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Rod photoreceptors protect from cone degeneration-induced retinal remodeling and restore visual responses in zebrafish. J Neurosci 2013; 33:1804-14. [PMID: 23365220 DOI: 10.1523/jneurosci.2910-12.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Humans are largely dependent upon cone-mediated vision. However, death or dysfunction of rods, the predominant photoreceptor subtype, results in secondary loss of cones, remodeling of retinal circuitry, and blindness. The changes in circuitry may contribute to the vision deficit and undermine attempts at restoring sight. We exploit zebrafish larvae as a genetic model to specifically characterize changes associated with photoreceptor degenerations in a cone-dominated retina. Photoreceptors form synapses with two types of second-order neurons, bipolar cells, and horizontal cells. Using cell-specific reporter gene expression and immunolabeling for postsynaptic glutamate receptors, significant remodeling is observed following cone degeneration in the pde6c(w59) larval retina but not rod degeneration in the Xops:mCFP(q13) line. In adults, rods and cones are present in approximately equal numbers, and in pde6c(w59) mutants glutamate receptor expression and synaptic structures in the outer plexiform layer are preserved, and visual responses are gained in these once blind fish. We propose that the abundance of rods in the adult protects the retina from cone degeneration-induced remodeling. We test this hypothesis by genetically manipulating the number of rods in larvae. We show that an increased number and uniform distribution of rods in lor/tbx2b(p25bbtl) or six7 morpholino-injected larvae protect from pde6c(w59)-induced secondary changes. The observations that remodeling is a common consequence of photoreceptor death across species, and that in zebrafish a small number of surviving photoreceptors afford protection from degeneration-induced changes, provides a model for systematic analysis of factors that slow or even prevent the secondary deteriorations associated with neural degenerative disease.
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41
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Li YN, Tsujimura T, Kawamura S, Dowling JE. Bipolar cell-photoreceptor connectivity in the zebrafish (Danio rerio) retina. J Comp Neurol 2013; 520:3786-802. [PMID: 22907678 DOI: 10.1002/cne.23168] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bipolar cells convey luminance, spatial, and color information from photoreceptors to amacrine and ganglion cells. We studied the photoreceptor connectivity of 321 bipolar cells in the adult zebrafish retina. 1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) was inserted into whole-mounted transgenic zebrafish retinas to label bipolar cells. The photoreceptors that connect to these DiI-labeled cells were identified by transgenic fluorescence or their positions relative to the fluorescent cones, as cones are arranged in a highly ordered mosaic: rows of alternating blue- (B) and ultraviolet-sensitive (UV) single cones alternate with rows of red-(R) and green-sensitive (G) double cones. Rod terminals intersperse among cone terminals. As many as 18 connectivity subtypes were observed, 9 of which-G, GBUV, RG, RGB, RGBUV, RGRod, RGBRod, RGBUVRod, and RRod bipolar cells-accounted for 96% of the population. Based on their axon terminal stratification, these bipolar cells could be further subdivided into ON, OFF, and ON-OFF cells. The dendritic spread size, soma depth and size, and photoreceptor connections of the 308 bipolar cells within the nine common connectivity subtypes were determined, and their dendritic tree morphologies and axonal stratification patterns compared. We found that bipolar cells with the same axonal stratification patterns could have heterogeneous photoreceptor connectivity whereas bipolar cells with the same dendritic tree morphology usually had the same photoreceptor connectivity, although their axons might stratify on different levels.
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Affiliation(s)
- Yong N Li
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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42
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Abstract
DiOlistic labeling utilizes a particle-mediated delivery system to incorporate dye into cells. Because of its random nature, this technique generates sparse fluorescent labeling which is well suited for the study of neuronal dendritic branching and dendritic spine morphology. DiOlistics is a quick, reliable and nontoxic method that can be used in combination with other techniques such as immunostaining, biolistic DNA transfection, and retrograde tracing. In this article, we describe the methods for diOlistic labeling of neurons from rodent brain slices using DiI and the imaging of neuronal and synaptic morphology using confocal microscopy.
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Affiliation(s)
- Nyssa Sherazee
- Section on Neuronal Structure, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
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43
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Gestri G, Link BA, Neuhauss SCF. The visual system of zebrafish and its use to model human ocular diseases. Dev Neurobiol 2012; 72:302-27. [PMID: 21595048 DOI: 10.1002/dneu.20919] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Free swimming zebrafish larvae depend mainly on their sense of vision to evade predation and to catch prey. Hence, there is strong selective pressure on the fast maturation of visual function and indeed the visual system already supports a number of visually driven behaviors in the newly hatched larvae.The ability to exploit the genetic and embryonic accessibility of the zebrafish in combination with a behavioral assessment of visual system function has made the zebrafish a popular model to study vision and its diseases.Here, we review the anatomy, physiology, and development of the zebrafish eye as the basis to relate the contributions of the zebrafish to our understanding of human ocular diseases.
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Affiliation(s)
- Gaia Gestri
- Department of Cell and Developmental Biology, University College, London,UK.
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44
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Zebrafish inner retina: local signals for spatial position, luminance, and color contrast. Vis Neurosci 2012; 29:229-36. [PMID: 22877609 DOI: 10.1017/s0952523812000259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The retina of the zebrafish (Danio rerio) provides an unusually favorable preparation for genetic and developmental studies of the retina. Although the retina has been studied extensively for two decades, the neuronal response of the inner retina is largely unknown. This report describes a prominent local field potential of the inner retina, the Proximal Negative Response (PNR). It is best evoked by small (100 μm) precisely positioned spots of light and is exceedingly sensitive to negative luminance contrast. The polarity, waveform, and other properties of the PNR suggest that it arises primarily from ON-OFF neurons of the proximal retina. The dominant response to negative contrast and its enhancement by light adaptation is believed due to a dominant presynaptic input from OFF bipolar cells. Color contrast was investigated by analyzing responses to a green bar moving on green versus red backgrounds. Over an intermediate range of irradiance, the response to green on red was larger than the response to green on green, thereby providing evidence for the encoding of color contrast. The present findings complement the classic principle of color contrast for human vision known as Kirschmann's third law and bring to mind the view of Walls that color contrast may have been the driving force for the evolution of color vision in lower vertebrates. In sum, the PNR of zebrafish provides clear evidence for the encoding of color and luminance contrast in the inner retina. It exhibits the defining properties common to many other vertebrates, reinforcing the view that the zebrafish may further serve as a model for retinal function and that the PNR may provide a new approach for studies of development, genetics, and retinal degeneration in zebrafish.
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45
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Tarboush R, Chapman GB, Connaughton VP. Ultrastructure of the distal retina of the adult zebrafish, Danio rerio. Tissue Cell 2012; 44:264-79. [PMID: 22608306 DOI: 10.1016/j.tice.2012.04.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 02/07/2012] [Accepted: 04/20/2012] [Indexed: 01/01/2023]
Abstract
The organization, morphological characteristics, and synaptic structure of photoreceptors in the adult zebrafish retina were studied using light and electron microscopy. Adult photoreceptors show a typical ordered tier arrangement with rods easily distinguished from cones based on outer segment (OS) morphology. Both rods and cones contain mitochondria within the inner segments (IS), including the large, electron-dense megamitochondria previously described (Kim et al.) Four major ultrastructural differences were observed between zebrafish rods and cones: (1) the membranes of cone lamellar disks showed a wider variety of relationships to the plasma membrane than those of rods, (2) cone pedicles typically had multiple synaptic ribbons, while rod spherules had 1-2 ribbons, (3) synaptic ribbons in rod spherules were ∼2 times longer than ribbons in cone pedicles, and (4) rod spherules had a more electron-dense cytoplasm than cone pedicles. Examination of photoreceptor terminals identified four synaptic relationships at cone pedicles: (1) invaginating contacts postsynaptic to cone ribbons forming dyad, triad, and quadrad synapses, (2) presumed gap junctions connecting adjacent postsynaptic processes invaginating into cone terminals, (3) basal junctions away from synaptic ribbons, and (4) gap junctions between adjacent photoreceptor terminals. More vitread and slightly farther removed from photoreceptor terminals, extracellular microtubule-like structures were identified in association with presumed horizontal cell processes in the OPL. These findings, the first to document the ultrastructure of the distal retina in adult zebrafish, indicate that zebrafish photoreceptors have many characteristics similar to other species, further supporting the use of zebrafish as a model for the vertebrate visual system.
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Affiliation(s)
- R Tarboush
- Department of Biology, American University, Washington, DC 20016, USA.
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46
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Encoding of luminance and contrast by linear and nonlinear synapses in the retina. Neuron 2012; 73:758-73. [PMID: 22365549 PMCID: PMC3314971 DOI: 10.1016/j.neuron.2011.12.023] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2011] [Indexed: 01/01/2023]
Abstract
Understanding how neural circuits transmit information is technically challenging because the neural code is contained in the activity of large numbers of neurons and synapses. Here, we use genetically encoded reporters to image synaptic transmission across a population of sensory neurons-bipolar cells in the retina of live zebrafish. We demonstrate that the luminance sensitivities of these synapses varies over 10(4) with a log-normal distribution. About half the synapses made by ON and OFF cells alter their polarity of transmission as a function of luminance to generate a triphasic tuning curve with distinct maxima and minima. These nonlinear synapses signal temporal contrast with greater sensitivity than linear ones. Triphasic tuning curves increase the dynamic range over which bipolar cells signal light and improve the efficiency with which luminance information is transmitted. The most efficient synapses signaled luminance using just 1 synaptic vesicle per second per distinguishable gray level.
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47
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Sánchez-ramos C, Guerrera M, Bonnin-Arias C, Calavia M, Laurà R, Germanà A, Vega J. Expression of TRPV4 in the zebrafish retina during development. Microsc Res Tech 2012; 75:743-8. [DOI: 10.1002/jemt.21120] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 10/22/2011] [Indexed: 12/12/2022]
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Aquaporin-4 immunoreactivity in Müller and amacrine cells of marine teleost fish retina. Brain Res 2012; 1432:46-55. [DOI: 10.1016/j.brainres.2011.11.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Revised: 11/03/2011] [Accepted: 11/03/2011] [Indexed: 02/02/2023]
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Jang YJ, Yu SH, Lee ES, Jeon CJ. Two types of tyrosine hydroxylase-immunoreactive neurons in the zebrafish retina. Neurosci Res 2011; 71:124-33. [PMID: 21784111 DOI: 10.1016/j.neures.2011.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 07/05/2011] [Accepted: 07/06/2011] [Indexed: 10/18/2022]
Abstract
The purpose of the present study is to identify the dopaminergic amacrine (DA) cells in the inner nuclear layer (INL) of zebrafish retina through immunocytochemistry and quantitative analysis. Two types of tyrosine hydroxylase-immunoreactive (TH-IR) cells appeared on the basis of dendritic morphology and stratification patterns in the inner plexiform layer (IPL). The first (DA1) was bistratified, with branching planes in both s1 and s5 of the IPL. The second (DA2) was diffuse, with dendritic processes branched throughout the IPL. DA1 and DA2 cells corresponded morphologically to A(on)(-s1/s5) and A(diffuse)(-1) (Connaughton et al., 2004). The average number of total TH-IR cells was 1088±79cells per retina (n=5), and the mean density was 250±27cells/mm(2). Their density was highest in the mid central region of ventrotemporal retina and lowest in the periphery of dorsonasal retina. Quantitatively, 45.71% of the TH-IR cells were DA1 cells, while 54.29% were DA2 cells. No TH-IR cells expressed calbindin D28K, calretinin or parvalbumin, markers for the various INL cells present in several animals. Therefore the TH-IR cells in zebrafish are limited to very specific subpopulations of the amacrine cells.
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Affiliation(s)
- Yu-Jin Jang
- Department of Biology, College of Natural Sciences, and Brain Science and Engineering Institute, Kyungpook National University, Daegu 702-701, South Korea
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Cederlund ML, Morrissey ME, Baden T, Scholz D, Vendrell V, Lagnado L, Connaughton VP, Kennedy BN. Zebrafish Tg(7.2mab21l2:EGFP)ucd2 transgenics reveal a unique population of retinal amacrine cells. Invest Ophthalmol Vis Sci 2011; 52:1613-21. [PMID: 21051702 PMCID: PMC3925879 DOI: 10.1167/iovs.10-5376] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Amacrine cells constitute a diverse, yet poorly characterized, cell population in the inner retina. Here, the authors sought to characterize the morphology, molecular physiology, and electrophysiology of a subpopulation of EGFP-expressing retinal amacrine cells identified in a novel zebrafish transgenic line. METHODS After 7.2 kb of the zebrafish mab21l2 promoter was cloned upstream of EGFP, it was used to create the Tg(7.2mab21l2:EGFP)ucd2 transgenic line. Transgenic EGFP expression was analyzed by fluorescence microscopy in whole mount embryos, followed by detailed analysis of EGFP-expressing amacrine cells using fluorescence microscopy, immunohistochemistry, and electrophysiology. RESULTS A 7.2-kb fragment of the mab21l2 promoter region is sufficient to drive transgene expression in the developing lens and tectum. Intriguingly, EGFP was also observed in differentiated amacrine cells. EGFP-labeled amacrine cells in Tg(7.2mab21l2:EGFP)ucd2 constitute a novel GABA- and glycine-negative amacrine subpopulation. Morphologically, EGFP-expressing cells stratify in sublamina 1 to 2 (type 1 OFF) or sublamina 3 to 4 (type 1 ON) or branch diffusely (type 2). Electrophysiologically, these cells segregate into amacrine cells with somas in the vitreal part of the INL and linear responses to current injection or, alternatively, amacrine cells with somas proximal to the IPL and active oscillatory voltage signals. CONCLUSIONS; The novel transgenic line Tg(7.2mab21l2:EGFP)ucd2 uncovers a unique subpopulation of retinal amacrine cells.
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Affiliation(s)
- Maria L. Cederlund
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Maria E. Morrissey
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Tom Baden
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Dimitri Scholz
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Victor Vendrell
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Leon Lagnado
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Breandán N. Kennedy
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin, Ireland
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