1
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Morshedian A, Jiang Z, Radu RA, Fain GL, Sampath AP. Genetic manipulation of rod-cone differences in mouse retina. PLoS One 2024; 19:e0300584. [PMID: 38709779 PMCID: PMC11073714 DOI: 10.1371/journal.pone.0300584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 03/01/2024] [Indexed: 05/08/2024] Open
Abstract
Though rod and cone photoreceptors use similar phototransduction mechanisms, previous model calculations have indicated that the most important differences in their light responses are likely to be differences in amplification of the G-protein cascade, different decay rates of phosphodiesterase (PDE) and pigment phosphorylation, and different rates of turnover of cGMP in darkness. To test this hypothesis, we constructed TrUx;GapOx rods by crossing mice with decreased transduction gain from decreased transducin expression, with mice displaying an increased rate of PDE decay from increased expression of GTPase-activating proteins (GAPs). These two manipulations brought the sensitivity of TrUx;GapOx rods to within a factor of 2 of WT cone sensitivity, after correcting for outer-segment dimensions. These alterations did not, however, change photoreceptor adaptation: rods continued to show increment saturation though at a higher background intensity. These experiments confirm model calculations that rod responses can mimic some (though not all) of the features of cone responses after only a few changes in the properties of transduction proteins.
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Affiliation(s)
- Ala Morshedian
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Zhichun Jiang
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Roxana A. Radu
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Gordon L. Fain
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Alapakkam P. Sampath
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
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Takita S, Jahan S, Imanishi S, Harikrishnan H, LePage D, Mann RJ, Conlon RA, Miyagi M, Imanishi Y. Rhodopsin mislocalization drives ciliary dysregulation in a novel autosomal dominant retinitis pigmentosa knock-in mouse model. FASEB J 2024; 38:e23606. [PMID: 38648465 PMCID: PMC11047207 DOI: 10.1096/fj.202302260rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 03/22/2024] [Accepted: 03/29/2024] [Indexed: 04/25/2024]
Abstract
Rhodopsin mislocalization encompasses various blind conditions. Rhodopsin mislocalization is the primary factor leading to rod photoreceptor dysfunction and degeneration in autosomal dominant retinitis pigmentosa (adRP) caused by class I mutations. In this study, we report a new knock-in mouse model that harbors a class I Q344X mutation in the endogenous rhodopsin gene, which causes rod photoreceptor degeneration in an autosomal dominant pattern. In RhoQ344X/+ mice, mRNA transcripts from the wild-type (Rho) and RhoQ344X mutant rhodopsin alleles are expressed at equal levels. However, the amount of RHOQ344X mutant protein is 2.7 times lower than that of wild-type rhodopsin, a finding consistent with the rapid degradation of the mutant protein. Immunofluorescence microscopy indicates that RHOQ344X is mislocalized to the inner segment and outer nuclear layers of rod photoreceptors in both RhoQ344X/+ and RhoQ344X/Q344X mice, confirming the essential role of the C-terminal VxPx motif in promoting OS delivery of rhodopsin. The mislocalization of RHOQ344X is associated with the concurrent mislocalization of wild-type rhodopsin in RhoQ344X/+ mice. To understand the global changes in proteostasis, we conducted quantitative proteomics analysis and found attenuated expression of rod-specific OS membrane proteins accompanying reduced expression of ciliopathy causative gene products, including constituents of BBSome and axonemal dynein subunit. Those studies unveil a novel negative feedback regulation involving ciliopathy-associated proteins. In this process, a defect in the trafficking signal leads to a reduced quantity of the trafficking apparatus, culminating in a widespread reduction in the transport of ciliary proteins.
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Affiliation(s)
- Shimpei Takita
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sultana Jahan
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sanae Imanishi
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Hemavathy Harikrishnan
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - David LePage
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Rachel J. Mann
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Ronald A. Conlon
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Masaru Miyagi
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Yoshikazu Imanishi
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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3
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Mellen RW, Calabro KR, McCullough KT, Crosson SM, Cova ADL, Fajardo D, Xu E, Boye SL, Boye SE. Development of an AAV-CRISPR-Cas9-based treatment for dominant cone-rod dystrophy 6. Mol Ther Methods Clin Dev 2023; 30:48-64. [PMID: 37361352 PMCID: PMC10285452 DOI: 10.1016/j.omtm.2023.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023]
Abstract
Cone-rod dystrophy 6 (CORD6) is caused by gain-of-function mutations in the GUCY2D gene, which encodes retinal guanylate cyclase-1 (RetGC1). There are currently no treatments available for this autosomal dominant disease, which is characterized by severe, early-onset visual impairment. The purpose of our study was to develop an adeno-associated virus (AAV)-CRISPR-Cas9-based approach referred to as "ablate and replace" and evaluate its therapeutic potential in mouse models of CORD6. This two-vector system delivers (1) CRISPR-Cas9 targeted to the early coding sequence of the wild-type and mutant GUCY2D alleles and (2) a CRISPR-Cas9-resistant cDNA copy of GUCY2D ("hardened" GUCY2D). Together, these vectors knock out ("ablate") expression of endogenous RetGC1 in photoreceptors and supplement ("replace") a healthy copy of exogenous GUCY2D. First, we confirmed that ablation of mutant R838S GUCY2D was therapeutic in a transgenic mouse model of CORD6. Next, we established a proof of concept for "ablate and replace" and optimized vector doses in Gucy2e+/-:Gucy2f-/- and Gucy2f-/- mice, respectively. Finally, we confirmed that the "ablate and replace" approach stably preserved retinal structure and function in a novel knockin mouse model of CORD6, the RetGC1 (hR838S, hWT) mouse. Taken together, our results support further development of the "ablate and replace" approach for treatment of CORD6.
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Affiliation(s)
- Russell W. Mellen
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Kaitlyn R. Calabro
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - K. Tyler McCullough
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Sean M. Crosson
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Alejandro de la Cova
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Diego Fajardo
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Emily Xu
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Sanford L. Boye
- Powell Gene Therapy Center, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Shannon E. Boye
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
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4
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Skiba NP, Lewis TR, Spencer WJ, Castillo CM, Shevchenko A, Arshavsky VY. Absolute Quantification of Photoreceptor Outer Segment Proteins. J Proteome Res 2023; 22:2703-2713. [PMID: 37493966 PMCID: PMC10513726 DOI: 10.1021/acs.jproteome.3c00267] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Photoreceptor cells generate neuronal signals in response to capturing light. This process, called phototransduction, takes place in a highly specialized outer segment organelle. There are significant discrepancies in the reported amounts of many proteins supporting this process, particularly those of low abundance, which limits our understanding of their molecular organization and function. In this study, we used quantitative mass spectrometry to simultaneously determine the abundances of 20 key structural and functional proteins residing in mouse rod outer segments. We computed the absolute number of molecules of each protein residing within an individual outer segment and the molar ratio among all 20 proteins. The molar ratios of proteins comprising three well-characterized constitutive complexes in outer segments differed from the established subunit stoichiometries of these complexes by less than 7%, highlighting the exceptional precision of our quantification. Overall, this study resolves multiple existing discrepancies regarding the outer segment abundances of these proteins, thereby advancing our understanding of how the phototransduction pathway functions as a single, well-coordinated molecular ensemble.
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Affiliation(s)
- Nikolai P. Skiba
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
| | - Tylor R. Lewis
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
| | - William J. Spencer
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
| | - Carson M. Castillo
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
| | - Andrej Shevchenko
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany 01307
| | - Vadim Y. Arshavsky
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710
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5
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Li S, Ma H, Yang F, Ding X. cGMP Signaling in Photoreceptor Degeneration. Int J Mol Sci 2023; 24:11200. [PMID: 37446378 PMCID: PMC10342299 DOI: 10.3390/ijms241311200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023] Open
Abstract
Photoreceptors in the retina are highly specialized neurons with photosensitive molecules in the outer segment that transform light into chemical and electrical signals, and these signals are ultimately relayed to the visual cortex in the brain to form vision. Photoreceptors are composed of rods and cones. Rods are responsible for dim light vision, whereas cones are responsible for bright light, color vision, and visual acuity. Photoreceptors undergo progressive degeneration over time in many hereditary and age-related retinal diseases. Despite the remarkable heterogeneity of disease-causing genes, environmental factors, and pathogenesis, the progressive death of rod and cone photoreceptors ultimately leads to loss of vision/blindness. There are currently no treatments available for retinal degeneration. Cyclic guanosine 3', 5'-monophosphate (cGMP) plays a pivotal role in phototransduction. cGMP governs the cyclic nucleotide-gated (CNG) channels on the plasma membrane of the photoreceptor outer segments, thereby regulating membrane potential and signal transmission. By gating the CNG channels, cGMP regulates cellular Ca2+ homeostasis and signal transduction. As a second messenger, cGMP activates the cGMP-dependent protein kinase G (PKG), which regulates numerous targets/cellular events. The dysregulation of cGMP signaling is observed in varieties of photoreceptor/retinal degenerative diseases. Abnormally elevated cGMP signaling interferes with various cellular events, which ultimately leads to photoreceptor degeneration. In line with this, strategies to reduce cellular cGMP signaling result in photoreceptor protection in mouse models of retinal degeneration. The potential mechanisms underlying cGMP signaling-induced photoreceptor degeneration involve the activation of PKG and impaired Ca2+ homeostasis/Ca2+ overload, resulting from overactivation of the CNG channels, as well as the subsequent activation of the downstream cellular stress/death pathways. Thus, targeting the cellular cGMP/PKG signaling and the Ca2+-regulating pathways represents a significant strategy for photoreceptor protection in retinal degenerative diseases.
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Affiliation(s)
| | | | | | - Xiqin Ding
- Department of Cell Biology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.L.); (H.M.); (F.Y.)
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6
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Gesemann M, Neuhauss SCF. Evolution of visual guanylyl cyclases and their activating proteins with respect to clade and species-specific visual system adaptation. Front Mol Neurosci 2023; 16:1131093. [PMID: 37008786 PMCID: PMC10061024 DOI: 10.3389/fnmol.2023.1131093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 02/27/2023] [Indexed: 03/18/2023] Open
Abstract
Membrane guanylyl cyclase receptors are important regulators of local cGMP production, critically influencing cell growth and differentiation as well as ion transport, blood pressure and calcium feedback of vertebrate phototransduction. Currently, seven different subtypes of membrane guanylyl cyclase receptors have been characterized. These receptors have tissue specific expression and are activated either by small extracellular ligands, changing CO2 concentrations or, in the case of visual guanylyl cyclases, intracellularly interacting Ca2+-dependent activating proteins. In this report, we focus on the visual guanylyl cyclase receptors (GCs) GC-E (gucy2d/e) and GC-F (gucy2f) and their activating proteins (GCAP1/2/3; guca1a/b/c). While gucy2d/e has been detected in all analyzed vertebrates, GC-F receptors are missing in several clades (reptiles, birds, and marsupials) and/or individual species. Interestingly, the absence of GC-F in highly visual sauropsida species with up to 4 different cone-opsins is compensated by an increased number of guanylyl cyclase activating proteins, whereas in nocturnal or visually impaired species with reduced spectral sensitivity it is consolidated by the parallel inactivation of these activators. In mammals, the presence of GC-E and GC-F is accompanied by the expression of one to three GCAPs, whereas in lizards and birds, up to five different GCAPs are regulating the activity of the single GC-E visual membrane receptor. In several nearly blind species, a single GC-E enzyme is often accompanied by a single variant of GCAP, suggesting that one cyclase and one activating protein are both sufficient and required for conferring the basic detection of light.
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7
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Boye SL, O’Riordan C, Morris J, Lukason M, Compton D, Baek R, Elmore DM, Peterson J, Fajardo D, McCullough KT, Scaria A, McVie-Wylie A, Boye SE. Preclinical studies in support of phase I/II clinical trials to treat GUCY2D-associated Leber congenital amaurosis. Mol Ther Methods Clin Dev 2023; 28:129-145. [PMID: 36654798 PMCID: PMC9830033 DOI: 10.1016/j.omtm.2022.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Mutations in GUCY2D are associated with severe early-onset retinal dystrophy, Leber congenital amaurosis type 1 (LCA1), a leading cause of blindness in children. Despite a high degree of visual disturbance stemming from photoreceptor dysfunction, patients with LCA1 largely retain normal photoreceptor structure, suggesting that they are good candidates for gene replacement therapy. The purpose of this study was to conduct the preclinical and IND-enabling experiments required to support clinical application of AAV5-hGRK1-GUCY2D in patients harboring biallelic recessive mutations in GUCY2D. Preclinical studies were conducted in mice to evaluate the effect of vector manufacturing platforms and transgene species on the therapeutic response. Dose-ranging studies were conducted in cynomolgus monkeys to establish the minimum dose required for efficient photoreceptor transduction. Good laboratory practice (GLP) studies evaluated systemic biodistribution in rats and toxicology in non-human primates (NHPs). These results expanded our knowledge of dose response for an AAV5-vectored transgene under control of the human rhodopsin kinase (hGRK1) promoter in NHPs with respect to photoreceptor transduction and safety and, in combination with the rat biodistribution and mouse efficacy studies, informed the design of a first-in-human clinical study in patients with LCA1.
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Affiliation(s)
- Sanford L. Boye
- Powell Gene Therapy Center, Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA
| | | | | | | | | | | | | | | | | | | | | | | | - Shannon E. Boye
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, PO Box 100296, Gainesville, FL 32610, USA
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8
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Gulati S, Palczewski K. Structural view of G protein-coupled receptor signaling in the retinal rod outer segment. Trends Biochem Sci 2023; 48:172-186. [PMID: 36163145 PMCID: PMC9868064 DOI: 10.1016/j.tibs.2022.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 01/26/2023]
Abstract
Visual phototransduction is the most extensively studied G protein-coupled receptor (GPCR) signaling pathway because of its quantifiable stimulus, non-redundancy of genes, and immense importance in vision. We summarize recent discoveries that have advanced our understanding of rod outer segment (ROS) morphology and the pathological basis of retinal diseases. We have combined recently published cryo-electron tomography (cryo-ET) data on the ROS with structural knowledge on individual proteins to define the precise spatial limitations under which phototransduction occurs. Although hypothetical, the reconstruction of the rod phototransduction system highlights the potential roles of phosphodiesterase 6 (PDE6) and guanylate cyclases (GCs) in maintaining the spacing between ROS discs, suggesting a plausible mechanism by which intrinsic optical signals are generated in the retina.
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Affiliation(s)
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute and the Department of Ophthalmology, Center for Translational Vision Research, Department of Physiology and Biophysics, Department of Chemistry, Molecular Biology, and Biochemistry, University of California Irvine, 850 Health Sciences Road, Irvine, CA 92697-4375, USA.
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9
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Skiba NP, Lewis TR, Spencer WJ, Castillo CM, Shevchenko A, Arshavsky VY. Absolute quantification of photoreceptor outer segment proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.19.524794. [PMID: 36711880 PMCID: PMC9882265 DOI: 10.1101/2023.01.19.524794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Photoreceptor cells generate neuronal signals in response to capturing light. This process, called phototransduction, takes place in a highly specialized outer segment organelle. There are significant discrepancies in the reported amounts of many proteins supporting this process, particularly those of low abundance, which limits our understanding of their molecular organization and function. In this study, we used quantitative mass spectrometry to simultaneously measure the outer segment content of twenty key structural and functional proteins. We determined the molar ratio amongst all twenty proteins as well as the number of molecules of each protein residing within an outer segment. To assess the precision of this quantification, we took advantage of the fact that seven of these proteins exist within three constitutive complexes of well-established subunit stoichiometries. Remarkably, our measurements differed from these stoichiometries by less than 7%, highlighting the exceptional precision of our quantification. This allowed us to resolve the existing discrepancies regarding the outer segment abundances of these proteins, thereby advancing our understanding of how the phototransduction pathway functions as a single, well-coordinated molecular ensemble.
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10
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Naggert ASEN, Collin GB, Wang J, Krebs MP, Chang B. A mouse model of cone photoreceptor function loss (cpfl9) with degeneration due to a mutation in Gucy2e. Front Mol Neurosci 2023; 15:1080136. [PMID: 36698779 PMCID: PMC9868315 DOI: 10.3389/fnmol.2022.1080136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/15/2022] [Indexed: 01/11/2023] Open
Abstract
During routine screening of mouse strains and stocks by the Eye Mutant Resource at The Jackson Laboratory for genetic mouse models of human ocular disorders, we identified cpfl9, a mouse model with cone photoreceptor function loss. The mice exhibited an early-onset phenotype that was easily recognized by the absence of a cone-mediated b-wave electroretinography response and by a reduction in rod-mediated photoresponses at four weeks of age. By genetic mapping and high-throughput sequencing of a whole exome capture library of cpfl9, a homozygous 25 bp deletion within exon 11 of the Gucy2e gene was identified, which is predicted to result in a frame shift leading to premature termination. The corresponding protein in human, retinal guanylate cyclase 1 (GUCY2D), plays an important role in rod and cone photoreceptor cell function. Loss-of-function mutations in human GUCY2D cause LCA1, one of the most common forms of Leber congenital amaurosis, which results in blindness at birth or in early childhood. The early loss of cone and reduced rod photoreceptor cell function in the cpfl9 mutant is accompanied by a later, progressive loss of cone and rod photoreceptor cells, which may be relevant to understanding disease pathology in a subset of LCA1 patients and in individuals with cone-rod dystrophy caused by recessive GUCY2D variants. cpfl9 mice will be useful for studying the role of Gucy2e in the retina.
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Pasquaré SJ, Chamorro-Aguirre E, Gaveglio VL. The endocannabinoid system in the visual process. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2022. [DOI: 10.1016/j.jpap.2022.100159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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12
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Short-Term Omega-3 Supplementation Modulates Novel Neurovascular and Fatty Acid Metabolic Proteome Changes in the Retina and Ophthalmic Artery of Mice with Targeted Cyp2c44 Gene Deletion. Cells 2022; 11:cells11213494. [PMID: 36359890 PMCID: PMC9658563 DOI: 10.3390/cells11213494] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/27/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022] Open
Abstract
Cytochrome P450 (CYP) gene mutations are a common predisposition associated with glaucoma. Although the molecular mechanisms are largely unknown, omega-3 polyunsaturated fatty acids (ω-3 PUFA) and their CYP-derived bioactive mediators play crucial roles in the ocular system. Here, we elucidated the proteome and cell-signalling alterations attributed to the main human CYP2C gene deficiency using a homologous murine model (Cyp2c44−/−), and unravelled the effects of acute ω-3 PUFA supplementation in two ocular vascular beds comprising the retrobulbar ophthalmic artery (OA) and retina (R). Male Cyp2c44−/− mice (KO) and their floxed littermates (WT) were gavaged daily for 7 days with 0.01 mL/g of ω-3 PUFA composed of menhaden fish oil. Another group in respective strains served as vehicle-treated controls. OA and R were isolated at day 8 post-treatment (n = 9/group) and subjected to mass spectrometry (MS)-based proteomics and in silico bioinformatics analyses. Cyp2c44−/− resulted in significant detrimental proteome changes associated with compromised vascular integrity and degeneration in the OA and R, respectively. However, notable changes in the OA after ω-3 PUFA intake were associated with the maintenance of intercellular junctional and endothelial cell functions, as well as activation of the fatty acid metabolic pathway in the KO mice. Conversely, ω-3 PUFA supplementation profoundly influenced the regulation of a large majority of retinal proteins involved in the preservation of neuronal and phototransduction activities in WT mice, namely synaptophysin, phosducin and guanylate cyclase-1, while significantly abrogating degenerative processes in the KO mice via the regulation of, namely, synaptotagmin-1 and beta-crystallin B2. In gist, this study demonstrated that dietary supplementation with ω-3 PUFA for a short period of seven days regulated specific neuro-vasculoprotective mechanisms to preserve the functionality of the OA and R in the absence of Cyp2c44. The potential adjunct use of ω-3 PUFA for glaucoma therapy needs further investigation.
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Jacobson SG, Cideciyan AV, Ho AC, Roman AJ, Wu V, Garafalo AV, Sumaroka A, Krishnan AK, Swider M, Mascio AA, Kay CN, Yoon D, Fujita KP, Boye SL, Peshenko IV, Dizhoor AM, Boye SE. Night vision restored in days after decades of congenital blindness. iScience 2022; 25:105274. [PMID: 36274938 PMCID: PMC9579015 DOI: 10.1016/j.isci.2022.105274] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/29/2022] [Accepted: 09/30/2022] [Indexed: 11/29/2022] Open
Abstract
Signaling of vision to the brain starts with the retinal phototransduction cascade which converts visible light from the environment into chemical changes. Vision impairment results when mutations inactivate proteins of the phototransduction cascade. A severe monogenically inherited blindness, Leber congenital amaurosis (LCA), is caused by mutations in the GUCY2D gene, leading to a molecular defect in the production of cyclic GMP, the second messenger of phototransduction. We studied two patients with GUCY2D-LCA who were undergoing gene augmentation therapy. Both patients had large deficits in rod photoreceptor-based night vision before intervention. Within days of therapy, rod vision in both patients changed dramatically; improvements in visual function and functional vision in these hyper-responding patients reached more than 3 log10 units (1000-fold), nearing healthy rod vision. Quick activation of the complex molecular pathways from retinal photoreceptor to visual cortex and behavior is thus possible in patients even after being disabled and dormant for decades.
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Affiliation(s)
- Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Allen C. Ho
- Wills Eye Hospital, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Alejandro J. Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Vivian Wu
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexandra V. Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arun K. Krishnan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Abraham A. Mascio
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Dan Yoon
- Atsena Therapeutics, Inc., Durham, NC 27709, USA
| | | | - Sanford L. Boye
- Department of Pediatrics, Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, FL 32601, USA
| | - Igor V. Peshenko
- Pennsylvania College of Optometry, Salus University, Elkins Park, PA 19027, USA
| | | | - Shannon E. Boye
- Department of Pediatrics, Division of Cellular and Molecular Therapy, University of Florida College of Medicine, Gainesville, FL 32611, USA
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14
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Ames JB. Structural basis of retinal membrane guanylate cyclase regulation by GCAP1 and RD3. Front Mol Neurosci 2022; 15:988142. [PMID: 36157073 PMCID: PMC9493048 DOI: 10.3389/fnmol.2022.988142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Retinal membrane guanylate cyclases (RetGC1 and RetGC2) are expressed in photoreceptor rod and cone cells, where they promote the onset of visual recovery during phototransduction. The catalytic activity of RetGCs is regulated by their binding to regulatory proteins, guanylate cyclase activating proteins (GCAP1-5) and the retinal degeneration 3 protein (RD3). RetGC1 is activated by its binding to Ca2+-free/Mg2+-bound GCAP1 at low cytosolic Ca2+ levels in light-activated photoreceptors. By contrast, RetGC1 is inactivated by its binding to Ca2+-bound GCAP1 and/or RD3 at elevated Ca2+ levels in dark-adapted photoreceptors. The Ca2+ sensitive cyclase activation helps to replenish the cytosolic cGMP levels in photoreceptors during visual recovery. Mutations in RetGC1, GCAP1 or RD3 that disable the Ca2+-dependent regulation of cyclase activity are genetically linked to rod/cone dystrophies and other inherited forms of blindness. Here I review the structural interaction of RetGC1 with GCAP1 and RD3. I propose a two-state concerted model in which the dimeric RetGC1 allosterically switches between active and inactive conformational states with distinct quaternary structures that are oppositely stabilized by the binding of GCAP1 and RD3. The binding of Ca2+-free/Mg2+-bound GCAP1 is proposed to activate the cyclase by stabilizing RetGC1 in an active conformation (R-state), whereas Ca2+-bound GCAP1 and/or RD3 inhibit the cyclase by locking RetGC1 in an inactive conformation (T-state). Exposed hydrophobic residues in GCAP1 (residues H19, Y22, M26, F73, V77, W94) are essential for cyclase activation and could be targeted by rational drug design for the possible treatment of rod/cone dystrophies.
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15
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Tian R, Guo H, Jin Z, Zhang F, Zhao J, Seim I. Molecular evolution of vision-related genes may contribute to marsupial photic niche adaptations. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.982073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Vision plays an essential role in the life of many animals. While most mammals are night-active (nocturnal), many have adapted to novel light environments. This includes diurnal (day-active) and crepuscular (twilight-active) species. Here, we used integrative approaches to investigate the molecular evolution of 112 vision-related genes across 19 genomes representing most marsupial orders. We found that four genes (GUCA1B, GUCY2F, RGR, and SWS2) involved in retinal phototransduction likely became functionally redundant in the ancestor of marsupials, a group of largely obligate nocturnal mammals. We also show evidence of rapid evolution and positive selection of bright-light vision genes in the common ancestor of Macropus (kangaroos, wallaroos, and wallabies). Macropus-specific amino acid substitutions in opsin genes (LWS and SWS1), in particular, may be an adaptation for crepuscular vision in this genus via opsin spectral sensitivity tuning. Our study set the stage for functional genetics studies and provides a stepping stone to future research efforts that fully capture the visual repertoire of marsupials.
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16
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Takei Y. Evolution of the membrane/particulate guanylyl cyclase: From physicochemical sensors to hormone receptors. Gen Comp Endocrinol 2022; 315:113797. [PMID: 33957096 DOI: 10.1016/j.ygcen.2021.113797] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/19/2021] [Accepted: 04/28/2021] [Indexed: 12/26/2022]
Abstract
Guanylyl cyclase (GC) is an enzyme that produces 3',5'-cyclic guanosine monophosphate (cGMP), one of the two canonical cyclic nucleotides used as a second messenger for intracellular signal transduction. The GCs are classified into two groups, particulate/membrane GCs (pGC) and soluble/cytosolic GCs (sGC). In relation to the endocrine system, pGCs include hormone receptors for natriuretic peptides (GC-A and GC-B) and guanylin peptides (GC-C), while sGC is a receptor for nitric oxide and carbon monoxide. Comparing the functions of pGCs in eukaryotes, it is apparent that pGCs perceive various environmental factors such as light, temperature, and various external chemical signals in addition to endocrine hormones, and transmit the information into the cell using the intracellular signaling cascade initiated by cGMP, e.g., cGMP-dependent protein kinases, cGMP-sensitive cyclic nucleotide-gated ion channels and cGMP-regulated phosphodiesterases. Among vertebrate pGCs, GC-E and GC-F are localized on retinal epithelia and are involved in modifying signal transduction from the photoreceptor, rhodopsin. GC-D and GC-G are localized in olfactory epithelia and serve as sensors at the extracellular domain for external chemical signals such as odorants and pheromones. GC-G also responds to guanylin peptides in the urine, which alters sensitivity to other chemicals. In addition, guanylin peptides that are secreted into the intestinal lumen, a pseudo-external environment, act on the GC-C on the apical membrane for regulation of epithelial transport. In this context, GC-C and GC-G appear to be in transition from exocrine pheromone receptor to endocrine hormone receptor. The pGCs also exist in various deuterostome and protostome invertebrates, and act as receptors for environmental, exocrine and endocrine factors including hormones. Tracing the evolutionary history of pGCs, it appears that pGCs first appeared as a sensor for physicochemical signals in the environment, and then evolved to function as hormone receptors. In this review, the author proposes an evolutionary history of pGCs that highlights the emerging role of the GC/cGMP system for signal transduction in hormone action.
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Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan.
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17
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Dai X, Jin X, Ye Q, Huang H, Duo L, Lu C, Bao J, Chen H. Intraperitoneal chromophore injections delay early-onset and rapid retinal cone degeneration in a mouse model of Leber congenital amaurosis. Exp Eye Res 2021; 212:108776. [PMID: 34582935 DOI: 10.1016/j.exer.2021.108776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 09/04/2021] [Accepted: 09/23/2021] [Indexed: 10/20/2022]
Abstract
Highly expressed in the retinal pigment epithelium (RPE), the RPE-specific 65-kDa (RPE65) enzyme is indispensable to generate 11-cis-retinal (11cRAL), a chromophore for rhodopsin and cone photopigments. RPE65 deficiency can lead to Leber congenital amaurosis type 2 (LCA2), in which the isomerization of photobleached all-trans-retinal into photosensitive 11cRAL is blocked, ultimately causing severe retinal dysfunction and degeneration. The related mouse models, which are constructed through gene knockout or caused by spontaneous mutations, morphologically present with early-onset and rapid retinal cone cells degeneration, including loss of short-wavelength-sensitive cone opsins (S-opsins) and mislocalization of medium-wavelength-sensitive cone opsins (M-opsins). Studies have shown that routine Rpe65 gene replacement therapy, mediated by an adeno-associated virus (AAV) vector, can restore RPE65 protein. However, AAV transfection and Rpe65 transgene expression require at least one to two weeks, and the treatment cannot fully block the early-onset cone degeneration. To determine the feasibility of delaying cone degeneration before gene therapy, we investigated the impact of 11cRAL treatment in an early-age LCA2 retinal degeneration 12 (rd12) mouse model. Similar to human patients, the mouse model carries a spontaneous mutation in the Rpe65 gene, which results in disrupted endogenous 11cRAL regeneration. We found that RPE65 deficiency did not notably affect rodent retinal vessels. Under red light illumination, the rd12 mice were intraperitoneally injected with exogenous 11cRAL from postnatal day (P) 14 to P21. Three days after the last injection, a notable recovery of retinal function was observed using scotopic and photopic electroretinograms. Using optical coherence tomography and histological analyses of the deficient retinas, we found changes in the thickness of the photoreceptor outer segment (OS); this change could be rescued by early 11cRAL treatment. In addition, the treatment notably preserved M- and S-opsins, both of which maintained appropriate localization inside cone cells, as shown by the wild-type mice. In contrast, the age-matched untreated rd12 mice were characterized by retinal S-opsin loss and M-opsin mislocalization from the photoreceptor OS to the inner segment, outer nuclear layer, or outer plexiform layer. Notably, 11cRAL treatment could not maintain retinal function for a long time. Ten days after the last injection, the rod and M-cone electroretinograms significantly decreased, and S-cone responses almost extinguished. Our findings suggest that early 11cRAL treatment is useful for restoring retinal function and rescuing morphology in the rd12 mouse model, and the early-onset and rapid cone degeneration can be delayed before gene therapy.
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Affiliation(s)
- Xufeng Dai
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China; State Key Laboratory of Ophthalmology, Optometry, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325027, China
| | - Xumin Jin
- Laboratory Animal Centre, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Qian Ye
- State Key Laboratory of Ophthalmology, Optometry, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325027, China
| | - Haixiao Huang
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Lan Duo
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China; State Key Laboratory of Ophthalmology, Optometry, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325027, China
| | - Chunjie Lu
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Jinhua Bao
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China; State Key Laboratory of Ophthalmology, Optometry, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325027, China.
| | - Hao Chen
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China; State Key Laboratory of Ophthalmology, Optometry, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang, 325027, China.
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18
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Retinal degeneration-3 protein attenuates photoreceptor degeneration in transgenic mice expressing dominant mutation of human retinal guanylyl cyclase. J Biol Chem 2021; 297:101201. [PMID: 34537244 PMCID: PMC8517212 DOI: 10.1016/j.jbc.2021.101201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 11/22/2022] Open
Abstract
Different forms of photoreceptor degeneration cause blindness. Retinal degeneration-3 protein (RD3) deficiency in photoreceptors leads to recessive congenital blindness. We proposed that aberrant activation of the retinal membrane guanylyl cyclase (RetGC) by its calcium-sensor proteins (guanylyl cyclase-activating protein [GCAP]) causes this retinal degeneration and that RD3 protects photoreceptors by preventing such activation. We here present in vivo evidence that RD3 protects photoreceptors by suppressing activation of both RetGC1 and RetGC2 isozymes. We further suggested that insufficient inhibition of RetGC by RD3 could contribute to some dominant forms of retinal degeneration. The R838S substitution in RetGC1 that causes autosomal-dominant cone-rod dystrophy 6, not only impedes deceleration of RetGC1 activity by Ca2+GCAPs but also elevates this isozyme's resistance to inhibition by RD3. We found that RD3 prolongs the survival of photoreceptors in transgenic mice harboring human R838S RetGC1 (R838S+). Overexpression of GFP-tagged human RD3 did not improve the calcium sensitivity of cGMP production in R838S+ retinas but slowed the progression of retinal blindness and photoreceptor degeneration. Fluorescence of the GFP-tagged RD3 in the retina only partially overlapped with immunofluorescence of RetGC1 or GCAP1, indicating that RD3 separates from the enzyme before the RetGC1:GCAP1 complex is formed in the photoreceptor outer segment. Most importantly, our in vivo results indicate that, in addition to the abnormal Ca2+ sensitivity of R838S RetGC1 in the outer segment, the mutated RetGC1 becomes resistant to inhibition by RD3 in a different cellular compartment(s) and suggest that RD3 overexpression could be utilized to reduce the severity of cone-rod dystrophy 6 pathology.
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19
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Gesemann M, Neuhauss SCF. Selective Gene Loss of Visual and Olfactory Guanylyl Cyclase Genes Following the Two Rounds of Vertebrate-Specific Whole-Genome Duplications. Genome Biol Evol 2021; 12:2153-2167. [PMID: 32915957 PMCID: PMC7674705 DOI: 10.1093/gbe/evaa192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2020] [Indexed: 12/12/2022] Open
Abstract
Photoreceptors convey visual information and come in two flavors; dim-light and bright-light dedicated rod and cones. Both cell types feature highly specialized phototransduction cascades that convert photonic energy into intracellular signals. Although a substantial amount of phototransduction gene ohnologs are expressed either in rods or cones, visual guanylyl cyclases (GCs) involved in the calcium (Ca2+) dependent feedback regulation of phototransduction are neither rod nor cone specific. The co-existence of visual GCs in both photoreceptor types suggests that specialization of these ohnologs occurred despite their overlapping expression. Here, we analyze gene retention and inactivation patterns of vertebrate visual and closely related olfactory GCs following two rounds (2R) of vertebrate-specific whole-genome duplication events (2R WGD). Although eutherians generally use two visual and one olfactory GC, independent inactivation occurred in some lineages. Sauropsids (birds, lizards, snakes, turtles, and crocodiles) generally have only one visual GC (GC-E). Additionally, turtles (testodes) also lost the olfactory GC (GC-D). Pseudogenization in mammals occurred in specific species/families likely according to functional needs (i.e., many species with reduced vision only have GC-E). Likewise, some species not relying on scent marks lack GC-D, the olfactory GC enzyme. Interestingly, in the case of fish, no species can be found with fewer than three (two visual and one olfactory) genes and the teleost-specific 3R WGD can increase this number to up to five. This suggests that vision in fish now requires at least two visual GCs.
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Affiliation(s)
- Matthias Gesemann
- Institute of Molecular Life Sciences, University of Zurich, Switzerland
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20
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Abstract
Inherited retinal diseases (IRDs) are an important cause of blindness worldwide. Over 270 genes have been associated with IRD. Genetic testing can determine the cause of the clinical disease in the majority of patients. However, at least 25-50% of patients with clinical diagnosis of IRD remain unsolved even after whole genome sequencing. Animal models of IRD can be useful for expanding the set of established IRD genes, to gain biological understanding of the function of these genes in the retina, and to test advanced therapeutics prior to human clinical trials. In this chapter some small and large animal models of IRD are discussed including some of the advantages and limitations of each for various forms of retinopathy.
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21
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Solanki AK, Biswal MR, Walterhouse S, Martin R, Kondkar AA, Knölker HJ, Rahman B, Arif E, Husain S, Montezuma SR, Nihalani D, Lobo GP. Loss of Motor Protein MYO1C Causes Rhodopsin Mislocalization and Results in Impaired Visual Function. Cells 2021; 10:cells10061322. [PMID: 34073294 PMCID: PMC8229726 DOI: 10.3390/cells10061322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/12/2022] Open
Abstract
Unconventional myosins, linked to deafness, are also proposed to play a role in retinal cell physiology. However, their direct role in photoreceptor function remains unclear. We demonstrate that systemic loss of the unconventional myosin MYO1C in mice, specifically causes rhodopsin mislocalization, leading to impaired visual function. Electroretinogram analysis of Myo1c knockout (Myo1c-KO) mice showed a progressive loss of photoreceptor function. Immunohistochemistry and binding assays demonstrated MYO1C localization to photoreceptor inner and outer segments (OS) and identified a direct interaction of rhodopsin with MYO1C. In Myo1c-KO retinas, rhodopsin mislocalized to rod inner segments (IS) and cell bodies, while cone opsins in OS showed punctate staining. In aged mice, the histological and ultrastructural examination of the phenotype of Myo1c-KO retinas showed progressively shorter photoreceptor OS. These results demonstrate that MYO1C is important for rhodopsin localization to the photoreceptor OS, and for normal visual function.
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Affiliation(s)
- Ashish K. Solanki
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (A.K.S.); (S.W.); (B.R.); (E.A.)
| | - Manas R. Biswal
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA;
| | - Stephen Walterhouse
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (A.K.S.); (S.W.); (B.R.); (E.A.)
| | - René Martin
- Faculty of Chemistry, Technische Universität Dresden, Bergstraße 66, 01069 Dresden, Germany; (R.M.); (H.-J.K.)
| | - Altaf A. Kondkar
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh 11411, Saudi Arabia;
| | - Hans-Joachim Knölker
- Faculty of Chemistry, Technische Universität Dresden, Bergstraße 66, 01069 Dresden, Germany; (R.M.); (H.-J.K.)
| | - Bushra Rahman
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (A.K.S.); (S.W.); (B.R.); (E.A.)
| | - Ehtesham Arif
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (A.K.S.); (S.W.); (B.R.); (E.A.)
| | - Shahid Husain
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA;
| | - Sandra R. Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 516 Delaware Street S.E., 9th Floor, Minneapolis, MN 55455, USA;
| | - Deepak Nihalani
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bldg. 2DEM, Room 6085, 6707 Democracy Blvd., Bethesda, MD 20817, USA
- Correspondence: (D.N.); (G.P.L.)
| | - Glenn Prazere Lobo
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (A.K.S.); (S.W.); (B.R.); (E.A.)
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA;
- Department of Ophthalmology and Visual Neurosciences, Lions Research Building, University of Minnesota, 2001 6th Street S.E., Room 225, Minneapolis, MN 55455, USA
- Correspondence: (D.N.); (G.P.L.)
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22
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Jacobson SG, Cideciyan AV, Ho AC, Peshenko IV, Garafalo AV, Roman AJ, Sumaroka A, Wu V, Krishnan AK, Sheplock R, Boye SL, Dizhoor AM, Boye SE. Safety and improved efficacy signals following gene therapy in childhood blindness caused by GUCY2D mutations. iScience 2021; 24:102409. [PMID: 33997691 PMCID: PMC8099775 DOI: 10.1016/j.isci.2021.102409] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/04/2021] [Accepted: 04/06/2021] [Indexed: 12/11/2022] Open
Abstract
A first-in-human clinical trial of gene therapy in Leber congenital amaurosis due to mutations in the GUCY2D gene is underway, and early results are summarized. A recombinant adeno-associated virus serotype 5 (rAAV5) vector carrying the human GUCY2D gene was delivered by subretinal injection to one eye in three adult patients with severe visual loss, nystagmus, but preserved retinal structure. Safety and efficacy parameters were monitored for 9 months post-operatively. No systemic toxicity was detected; there were no serious adverse events, and ocular adverse events resolved. P1 and P2 showed statistically significant rod photoreceptor vision improvement by full-field stimulus testing in the treated eye. P1 also showed improvement in pupillary responses. Visual acuity remained stable from baseline in P1 and P2. P3, however, showed a gain of 0.3 logMAR in the treated eye, indicating greater cone-photoreceptor function. The results show safety and both rod- and cone-mediated efficacy of this therapy.
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Affiliation(s)
- Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Allen C. Ho
- Wills Eye Hospital, Thomas Jefferson University, Philadelphia, PA, USA
| | - Igor V. Peshenko
- Pennsylvania College of Optometry, Salus University, Elkins Park, PA, USA
| | - Alexandra V. Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alejandro J. Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Vivian Wu
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Arun K. Krishnan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sanford L. Boye
- Department of Pediatrics, Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, FL, USA
| | | | - Shannon E. Boye
- Department of Pediatrics, Division of Cellular and Molecular Therapy, University of Florida College of Medicine, Gainesville, FL, USA
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Dizhoor AM, Olshevskaya EV, Peshenko IV. Retinal degeneration-3 protein promotes photoreceptor survival by suppressing activation of guanylyl cyclase rather than accelerating GMP recycling. J Biol Chem 2021; 296:100362. [PMID: 33539922 PMCID: PMC8047982 DOI: 10.1016/j.jbc.2021.100362] [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: 11/13/2020] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 01/19/2023] Open
Abstract
Retinal degeneration-3 protein (RD3) deficiency causes photoreceptor dysfunction and rapid degeneration in the rd3 mouse strain and in human Leber's congenital amaurosis, a congenital retinal dystrophy that results in early vision loss. However, the mechanisms responsible for photoreceptor death remain unclear. Here, we tested two hypothesized biochemical events that may underlie photoreceptor death: (i) the failure to prevent aberrant activation of retinal guanylyl cyclase (RetGC) by calcium-sensor proteins (GCAPs) versus (ii) the reduction of GMP phosphorylation rate, preventing its recycling to GDP/GTP. We found that GMP converts to GDP/GTP in the photoreceptor fraction of the retina ∼24-fold faster in WT mice and ∼400-fold faster in rd3 mice than GTP conversion to cGMP by RetGC. Adding purified RD3 to the retinal extracts inhibited RetGC 4-fold but did not affect GMP phosphorylation in wildtype or rd3 retinas. RD3-deficient photoreceptors rapidly degenerated in rd3 mice that were reared in constant darkness to prevent light-activated GTP consumption via RetGC and phosphodiesterase 6. In contrast, rd3 degeneration was alleviated by deletion of GCAPs. After 2.5 months, only ∼40% of photoreceptors remained in rd3/rd3 retinas. Deletion of GCAP1 or GCAP2 alone preserved 68% and 57% of photoreceptors, respectively, whereas deletion of GCAP1 and GCAP2 together preserved 86%. Taken together, our in vitro and in vivo results support the hypothesis that RD3 prevents photoreceptor death primarily by suppressing activation of RetGC by both GCAP1 and GCAP2 but do not support the hypothesis that RD3 plays a significant role in GMP recycling.
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Affiliation(s)
- Alexander M Dizhoor
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania, USA.
| | - Elena V Olshevskaya
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania, USA
| | - Igor V Peshenko
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania, USA.
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24
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Regulation of retinal membrane guanylyl cyclase (RetGC) by negative calcium feedback and RD3 protein. Pflugers Arch 2021; 473:1393-1410. [PMID: 33537894 PMCID: PMC8329130 DOI: 10.1007/s00424-021-02523-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 11/07/2022]
Abstract
This article presents a brief overview of the main biochemical and cellular processes involved in regulation of cyclic GMP production in photoreceptors. The main focus is on how the fluctuations of free calcium concentrations in photoreceptors between light and dark regulate the activity of retinal membrane guanylyl cyclase (RetGC) via calcium sensor proteins. The emphasis of the review is on the structure of RetGC and guanylyl cyclase activating proteins (GCAPs) in relation to their functional role in photoreceptors and congenital diseases of photoreceptors. In addition to that, the structure and function of retinal degeneration-3 protein (RD3), which regulates RetGC in a calcium-independent manner, is discussed in detail in connections with its role in photoreceptor biology and inherited retinal blindness.
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25
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Peshenko IV, Olshevskaya EV, Dizhoor AM. GUCY2D mutations in retinal guanylyl cyclase 1 provide biochemical reasons for dominant cone-rod dystrophy but not for stationary night blindness. J Biol Chem 2020; 295:18301-18315. [PMID: 33109612 PMCID: PMC7939455 DOI: 10.1074/jbc.ra120.015553] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/23/2020] [Indexed: 11/07/2022] Open
Abstract
Mutations in the GUCY2D gene coding for the dimeric human retinal membrane guanylyl cyclase (RetGC) isozyme RetGC1 cause various forms of blindness, ranging from rod dysfunction to rod and cone degeneration. We tested how the mutations causing recessive congenital stationary night blindness (CSNB), recessive Leber's congenital amaurosis (LCA1), and dominant cone-rod dystrophy-6 (CORD6) affected RetGC1 activity and regulation by RetGC-activating proteins (GCAPs) and retinal degeneration-3 protein (RD3). CSNB mutations R666W, R761W, and L911F, as well as LCA1 mutations R768W and G982VfsX39, disabled RetGC1 activation by human GCAP1, -2, and -3. The R666W and R761W substitutions compromised binding of GCAP1 with RetGC1 in HEK293 cells. In contrast, G982VfsX39 and L911F RetGC1 retained the ability to bind GCAP1 in cyto but failed to effectively bind RD3. R768W RetGC1 did not bind either GCAP1 or RD3. The co-expression of GUCY2D allelic combinations linked to CSNB did not restore RetGC1 activity in vitro The CORD6 mutation R838S in the RetGC1 dimerization domain strongly dominated the Ca2+ sensitivity of cyclase regulation by GCAP1 in RetGC1 heterodimer produced by co-expression of WT and the R838S subunits. It required higher Ca2+ concentrations to decelerate GCAP-activated RetGC1 heterodimer-6-fold higher than WT and 2-fold higher than the Ser838-harboring homodimer. The heterodimer was also more resistant than homodimers to inhibition by RD3. The observed biochemical changes can explain the dominant CORD6 blindness and recessive LCA1 blindness, both of which affect rods and cones, but they cannot explain the selective loss of rod function in recessive CSNB.
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Affiliation(s)
- Igor V Peshenko
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania, USA
| | - Elena V Olshevskaya
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania, USA
| | - Alexander M Dizhoor
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania, USA.
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Belluati A, Craciun I, Palivan CG. Bioactive Catalytic Nanocompartments Integrated into Cell Physiology and Their Amplification of a Native Signaling Cascade. ACS NANO 2020; 14:12101-12112. [PMID: 32869973 DOI: 10.1021/acsnano.0c05574] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Bioactive nanomaterials have the potential to overcome the limitations of classical pharmacological approaches by taking advantage of native pathways to influence cell behavior, interacting with them and eliciting responses. Herein, we propose a cascade system mediated by two catalytic nanocompartments (CNC) with biological activity. Activated by nitric oxide (NO) produced by inducible nitric oxidase synthase (iNOS), soluble guanylyl cyclase (sGC) produces cyclic guanosine monophosphate (cGMP), a second messenger that modulates a broad range of physiological functions. As alterations in cGMP signaling are implicated in a multitude of pathologies, its signaling cascade represents a viable target for therapeutic intervention. Following along this line, we encapsulated iNOS and sGC in two separate polymeric compartments that function in unison to produce NO and cGMP. Their action was tested in vitro by monitoring the derived changes in cytoplasmic calcium concentrations of HeLa and differentiated C2C12 myocytes, where the produced second messenger influenced the cellular homeostasis.
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Affiliation(s)
- Andrea Belluati
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
| | - Ioana Craciun
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
| | - Cornelia G Palivan
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
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McGowen MR, Tsagkogeorga G, Williamson J, Morin PA, Rossiter ASJ. Positive Selection and Inactivation in the Vision and Hearing Genes of Cetaceans. Mol Biol Evol 2020; 37:2069-2083. [DOI: 10.1093/molbev/msaa070] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Abstract
The transition to an aquatic lifestyle in cetaceans (whales and dolphins) resulted in a radical transformation in their sensory systems. Toothed whales acquired specialized high-frequency hearing tied to the evolution of echolocation, whereas baleen whales evolved low-frequency hearing. More generally, all cetaceans show adaptations for hearing and seeing underwater. To determine the extent to which these phenotypic changes have been driven by molecular adaptation, we performed large-scale targeted sequence capture of 179 sensory genes across the Cetacea, incorporating up to 54 cetacean species from all major clades as well as their closest relatives, the hippopotamuses. We screened for positive selection in 167 loci related to vision and hearing and found that the diversification of cetaceans has been accompanied by pervasive molecular adaptations in both sets of genes, including several loci implicated in nonsyndromic hearing loss. Despite these findings, however, we found no direct evidence of positive selection at the base of odontocetes coinciding with the origin of echolocation, as found in studies examining fewer taxa. By using contingency tables incorporating taxon- and gene-based controls, we show that, although numbers of positively selected hearing and nonsyndromic hearing loss genes are disproportionately high in cetaceans, counts of vision genes do not differ significantly from expected values. Alongside these adaptive changes, we find increased evidence of pseudogenization of genes involved in cone-mediated vision in mysticetes and deep-diving odontocetes.
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Affiliation(s)
- Michael R McGowen
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
- Department of Vertebrate Zoology, Smithsonian National Museum of Natural History, Washington, DC
| | - Georgia Tsagkogeorga
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
| | - Joseph Williamson
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
| | - Phillip A Morin
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA
| | - and Stephen J Rossiter
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
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Xu H, Enemchukwu N, Zhong X, Zhang O, Fu Y. Deletion of M-Opsin Prevents M Cone Degeneration in a Mouse Model of Leber Congenital Amaurosis. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:1059-1067. [PMID: 32084365 PMCID: PMC7237827 DOI: 10.1016/j.ajpath.2020.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/24/2019] [Accepted: 01/07/2020] [Indexed: 12/15/2022]
Abstract
Mutations in retinoid isomerase (RPE65) or lecithin-retinol acyltransferase (LRAT) disrupt 11-cis-retinal synthesis and cause Leber congenital amaurosis (LCA). Despite the success of recent RPE65 gene therapy, follow-up studies show that patients continue to experience photoreceptor degeneration and lose vision benefit over time. In Lrat-/- mouse model, mislocalized medium (M)-wavelength opsin was degraded, whereas mislocalized short (S)-wavelength opsin accumulated before the onset of cone degeneration. The mechanism for the foveal M/long-wavelength cone photoreceptor degeneration in LCA is unknown. By crossing Lrat-/- mice with a proteasome reporter mouse strain, this study showed that M-opsin-enriched dorsal cones in Lrat-/- mice exhibit proteasome stress because of the degradation of large amounts of M-opsin. Deletion of M-opsin relieves the proteasome stress and completely prevents M cone degeneration in Lrat-/-Opn1sw-/- mice (a pure M cone LCA model, Opn1sw encoding S-opsin) for at least 12 months. These results suggest that M-opsin degradation-associated proteasome stress plays a major role in M cone degeneration in Lrat-/- model. This finding may represent a general mechanism for M cone degeneration in multiple forms of cone degeneration because of M-opsin mislocalization and degradation. These results have important implications for the current gene therapy strategy for LCA that emphasizes the need for combinatorial therapies to both improve vision and slow photoreceptor degeneration.
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Affiliation(s)
- Hui Xu
- Interdepartmental Program in Neuroscience, Department of Ophthalmology, University of Utah, Salt Lake City, Utah; Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas; Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas
| | - Nduka Enemchukwu
- Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas; Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas
| | - Xiaoyue Zhong
- Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas; Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas; Rice University, Houston, Texas
| | - Olivia Zhang
- Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas; Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas; Rice University, Houston, Texas
| | - Yingbin Fu
- Interdepartmental Program in Neuroscience, Department of Ophthalmology, University of Utah, Salt Lake City, Utah; Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas; Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas.
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Collin GB, Gogna N, Chang B, Damkham N, Pinkney J, Hyde LF, Stone L, Naggert JK, Nishina PM, Krebs MP. Mouse Models of Inherited Retinal Degeneration with Photoreceptor Cell Loss. Cells 2020; 9:cells9040931. [PMID: 32290105 PMCID: PMC7227028 DOI: 10.3390/cells9040931] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degeneration (RD) leads to the impairment or loss of vision in millions of individuals worldwide, most frequently due to the loss of photoreceptor (PR) cells. Animal models, particularly the laboratory mouse, have been used to understand the pathogenic mechanisms that underlie PR cell loss and to explore therapies that may prevent, delay, or reverse RD. Here, we reviewed entries in the Mouse Genome Informatics and PubMed databases to compile a comprehensive list of monogenic mouse models in which PR cell loss is demonstrated. The progression of PR cell loss with postnatal age was documented in mutant alleles of genes grouped by biological function. As anticipated, a wide range in the onset and rate of cell loss was observed among the reported models. The analysis underscored relationships between RD genes and ciliary function, transcription-coupled DNA damage repair, and cellular chloride homeostasis. Comparing the mouse gene list to human RD genes identified in the RetNet database revealed that mouse models are available for 40% of the known human diseases, suggesting opportunities for future research. This work may provide insight into the molecular players and pathways through which PR degenerative disease occurs and may be useful for planning translational studies.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Navdeep Gogna
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jai Pinkney
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
| | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
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GCAP neuronal calcium sensor proteins mediate photoreceptor cell death in the rd3 mouse model of LCA12 congenital blindness by involving endoplasmic reticulum stress. Cell Death Dis 2020; 11:62. [PMID: 31980596 PMCID: PMC6981271 DOI: 10.1038/s41419-020-2255-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 01/01/2023]
Abstract
Loss-of-function mutations in the retinal degeneration 3 (RD3) gene cause inherited retinopathy with impaired rod and cone function and fast retinal degeneration in patients and in the natural strain of rd3 mice. The underlying physiopathology mechanisms are not well understood. We previously proposed that guanylate cyclase-activating proteins (GCAPs) might be key Ca2+-sensors mediating the physiopathology of this disorder, based on the demonstrated toxicity of GCAP2 when blocked in its Ca2+-free form at photoreceptor inner segments. We here show that the retinal degeneration in rd3 mice is substantially delayed by GCAPs ablation. While the number of retinal photoreceptor cells is halved in 6 weeks in rd3 mice, it takes 8 months to halve in rd3/rd3 GCAPs-/- mice. Although this substantial morphological rescue does not correlate with recovery of visual function due to very diminished guanylate cyclase activity in rd3 mice, it is very informative of the mechanisms underlying photoreceptor cell death. By showing that GCAP2 is mostly in its Ca2+-free-phosphorylated state in rd3 mice, we infer that the [Ca2+]i at rod inner segments is permanently low. GCAPs are therefore retained at the inner segment in their Ca2+-free, guanylate cyclase activator state. We show that in this conformational state GCAPs induce endoplasmic reticulum (ER) stress, mitochondrial swelling, and cell death. ER stress and mitochondrial swelling are early hallmarks of rd3 retinas preceding photoreceptor cell death, that are substantially rescued by GCAPs ablation. By revealing the involvement of GCAPs-induced ER stress in the physiopathology of Leber's congenital amaurosis 12 (LCA12), this work will aid to guide novel therapies to preserve retinal integrity in LCA12 patients to expand the window for gene therapy intervention to restore vision.
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Dizhoor AM, Olshevskaya EV, Peshenko IV. Retinal guanylyl cyclase activation by calcium sensor proteins mediates photoreceptor degeneration in an rd3 mouse model of congenital human blindness. J Biol Chem 2019; 294:13729-13739. [PMID: 31346032 DOI: 10.1074/jbc.ra119.009948] [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] [Received: 06/25/2019] [Revised: 07/22/2019] [Indexed: 01/19/2023] Open
Abstract
Deficiency of RD3 (retinal degeneration 3) protein causes recessive blindness and photoreceptor degeneration in humans and in the rd3 mouse strain, but the disease mechanism is unclear. Here, we present evidence that RD3 protects photoreceptors from degeneration by competing with guanylyl cyclase-activating proteins (GCAPs), which are calcium sensor proteins for retinal membrane guanylyl cyclase (RetGC). RetGC activity in rd3/rd3 retinas was drastically reduced but stimulated by the endogenous GCAPs at low Ca2+ concentrations. RetGC activity completely failed to accelerate in rd3/rd3GCAPs -/- hybrid photoreceptors, whose photoresponses remained drastically suppressed compared with the WT. However, ∼70% of the hybrid rd3/rd3GCAPs -/- photoreceptors survived past 6 months, in stark contrast to <5% in the nonhybrid rd3/rd3 retinas. GFP-tagged human RD3 inhibited GCAP-dependent activation of RetGC in vitro similarly to the untagged RD3. When transgenically expressed in rd3/rd3 mouse retinas under control of the rhodopsin promoter, the RD3GFP construct increased RetGC levels to near normal levels, restored dark-adapted photoresponses, and rescued rods from degeneration. The fluorescence of RD3GFP in rd3/rd3RD3GFP + retinas was mostly restricted to the rod photoreceptor inner segments, whereas GCAP1 immunofluorescence was concentrated predominantly in the outer segment. However, RD3GFP became distributed to the outer segments when bred into a GCAPs -/- genetic background. These results support the hypothesis that an essential biological function of RD3 is competition with GCAPs that inhibits premature cyclase activation in the inner segment. Our findings also indicate that the fast rate of degeneration in RD3-deficient photoreceptors results from the lack of this inhibition.
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Affiliation(s)
- Alexander M Dizhoor
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027
| | - Elena V Olshevskaya
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027
| | - Igor V Peshenko
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027
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Makino CL, Duda T, Pertzev A, Sharma RK. Experimental Approaches for Defining the Role of the Ca 2+-Modulated ROS-GC System in Retinal Rods of Mouse. Methods Mol Biol 2019; 1753:129-158. [PMID: 29564786 DOI: 10.1007/978-1-4939-7720-8_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Our ability to see is based on the activity of retinal rod and cone photoreceptors. Rods function when there is very little light, while cones operate at higher light levels. Photon absorption by rhodopsin activates a biochemical cascade that converts photic energy into a change in the membrane potential of the cell by decreasing the levels of a second messenger, cGMP, that control the gating of cation channels. But just as important as the activation of the cascade are the shut-off and recovery processes. The timing of shutoff and recovery ultimately affects sensitivity, temporal resolution and even the capacity for counting single photons. An important part of the recovery is restoration of cGMP through the action of rod outer segment membrane guanylate cyclases (ROS-GCs) and guanylate cyclase-activating proteins (GCAPs). In darkness, ROS-GCs catalyze the conversion of GTP to cGMP at a low rate, due to inhibition of cyclase activity by GCAPs. In the light, GCAP enhances ROS-GC activity. Mutations in the ROS-GC system can cause problems in vision, and even result in blindness due to photoreceptor death. The mouse has emerged as a particularly useful subject to study the role of ROS-GC because the technology for the manipulation of their genetics is advanced, making production of mice with targeted mutations much easier. Here we describe some experimental procedures for studying the retinal rods of wild-type and genetically engineered mice: biochemical assays of ROS-GC activity, immunohistochemistry, and single cell recording.
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Affiliation(s)
- Clint L Makino
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA, USA.
| | - Teresa Duda
- Unit of Regulatory and Molecular Biology, Research Divisions of Biochemistry and Molecular Biology, Salus University, Elkins Park, PA, USA
| | - Alexandre Pertzev
- Unit of Regulatory and Molecular Biology, Research Divisions of Biochemistry and Molecular Biology, Salus University, Elkins Park, PA, USA
| | - Rameshwar K Sharma
- Unit of Regulatory and Molecular Biology, Research Divisions of Biochemistry and Molecular Biology, Salus University, Elkins Park, PA, USA
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Peshenko IV, Yu Q, Lim S, Cudia D, Dizhoor AM, Ames JB. Retinal degeneration 3 (RD3) protein, a retinal guanylyl cyclase regulator, forms a monomeric and elongated four-helix bundle. J Biol Chem 2018; 294:2318-2328. [PMID: 30559291 DOI: 10.1074/jbc.ra118.006106] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/07/2018] [Indexed: 12/20/2022] Open
Abstract
Retinal degeneration 3 (RD3) protein promotes accumulation of retinal membrane guanylyl cyclase (RetGC) in the photoreceptor outer segment and suppresses RetGC activation by guanylyl cyclase-activating proteins (GCAPs). Mutations truncating RD3 cause severe congenital blindness by preventing the inhibitory binding of RD3 to the cyclase. The high propensity of RD3 to aggregate in solution has prevented structural analysis. Here, we produced a highly soluble variant of human RD3 (residues 18-160) that is monomeric and can still bind and negatively regulate RetGC. The NMR solution structure of RD3 revealed an elongated backbone structure (70 Å long and 30 Å wide) consisting of a four-helix bundle with a long unstructured loop between helices 1 and 2. The structure reveals that RD3 residues previously implicated in the RetGC binding map to a localized and contiguous area on the structure, involving a loop between helices 2 and 3 and adjacent parts of helices 3 and 4. The NMR structure of RD3 was validated by mutagenesis. Introducing Trp85 or Phe29 to replace Cys or Leu, respectively, disrupts packing in the hydrophobic core and lowers RD3's apparent affinity for RetGC1. Introducing a positive charge at the interface (Glu32 to Lys) also lowered the affinity. Conversely, introducing Val in place of Cys93 stabilized the hydrophobic core and increased the RD3 affinity for the cyclase. The NMR structure of RD3 presented here provides a structural basis for elucidating RD3-RetGC interactions relevant for normal vision or blindness.
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Affiliation(s)
- Igor V Peshenko
- From the Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027 and
| | - Qinhong Yu
- the Department of Chemistry, University of California, Davis, California 95616
| | - Sunghyuk Lim
- the Department of Chemistry, University of California, Davis, California 95616
| | - Diana Cudia
- the Department of Chemistry, University of California, Davis, California 95616
| | - Alexander M Dizhoor
- From the Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027 and
| | - James B Ames
- the Department of Chemistry, University of California, Davis, California 95616
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Sharon D, Wimberg H, Kinarty Y, Koch KW. Genotype-functional-phenotype correlations in photoreceptor guanylate cyclase (GC-E) encoded by GUCY2D. Prog Retin Eye Res 2018; 63:69-91. [DOI: 10.1016/j.preteyeres.2017.10.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/16/2017] [Accepted: 10/16/2017] [Indexed: 01/09/2023]
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Wimberg H, Janssen-Bienhold U, Koch KW. Control of the Nucleotide Cycle in Photoreceptor Cell Extracts by Retinal Degeneration Protein 3. Front Mol Neurosci 2018. [PMID: 29515371 PMCID: PMC5826319 DOI: 10.3389/fnmol.2018.00052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Retinal degeneration protein 3 (RD3) is crucial for photoreceptor cell survival and linked to Leber Congenital Amaurosis type 12 (LCA12), a hereditary retinal disease in humans. RD3 inhibits photoreceptor guanylate cyclases GC-E and GC-F and is involved in transport of GCs from the inner to the outer segments. Otherwise, its role in photoreceptor physiology is poorly understood. Here, we describe a new function of RD3. Purified RD3 evoked an increase in guanylate kinase activity, an enzyme that is involved in the nucleotide cycle in photoreceptors. We demonstrate a direct interaction between guanylate kinase and RD3 using back-scattering interferometry and show by immunohistochemistry of mouse retina sections that RD3 and guanylate kinase co-localize in photoreceptor inner segments and to a lesser extent in the outer plexiform layer. Our findings point toward a more complex function of RD3 in photoreceptors. The RD3 – guanylate kinase interaction may also play a role in other cellular systems, while the GC – RD3 interaction is exclusive to photoreceptors.
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Affiliation(s)
- Hanna Wimberg
- Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
| | - Ulrike Janssen-Bienhold
- Department of Neuroscience, Visual Neuroscience, University of Oldenburg, Oldenburg, Germany
| | - Karl-Wilhelm Koch
- Biochemistry, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
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López-Begines S, Plana-Bonamaisó A, Méndez A. Molecular determinants of Guanylate Cyclase Activating Protein subcellular distribution in photoreceptor cells of the retina. Sci Rep 2018; 8:2903. [PMID: 29440717 PMCID: PMC5811540 DOI: 10.1038/s41598-018-20893-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 01/26/2018] [Indexed: 11/10/2022] Open
Abstract
Retinal guanylate cyclase (RetGC) and guanylate cyclase activating proteins (GCAPs) play an important role during the light response in photoreceptor cells. Mutations in these proteins are linked to distinct forms of blindness. RetGC and GCAPs exert their role at the ciliary outer segment where phototransduction takes place. We investigated the mechanisms governing GCAP1 and GCAP2 distribution to rod outer segments by expressing selected GCAP1 and GCAP2 mutants as transient transgenes in the rods of GCAP1/2 double knockout mice. We show that precluding GCAP1 direct binding to RetGC (K23D/GCAP1) prevented its distribution to rod outer segments, while preventing GCAP1 activation of RetGC post-binding (W94A/GCAP1) did not. We infer that GCAP1 translocation to the outer segment strongly depends on GCAP1 binding affinity for RetGC, which points to GCAP1 requirement to bind to RetGC to be transported. We gain further insight into the distinctive regulatory steps of GCAP2 distribution, by showing that a phosphomimic at position 201 is sufficient to retain GCAP2 at proximal compartments; and that the bovine equivalent to blindness-causative mutation G157R/GCAP2 results in enhanced phosphorylation in vitro and significant retention at the inner segment in vivo, as likely contributing factors to the pathophysiology.
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Affiliation(s)
- Santiago López-Begines
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain.,Department of Physiology, University of Barcelona School of Medicine-Bellvitge Health Science Campus, Barcelona, Spain
| | - Anna Plana-Bonamaisó
- Department of Physiology, University of Barcelona School of Medicine-Bellvitge Health Science Campus, Barcelona, Spain
| | - Ana Méndez
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain. .,Department of Physiology, University of Barcelona School of Medicine-Bellvitge Health Science Campus, Barcelona, Spain.
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Wang M, Xu Z, Kong Y. The tubby-like proteins kingdom in animals and plants. Gene 2018; 642:16-25. [DOI: 10.1016/j.gene.2017.10.077] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 08/15/2017] [Accepted: 10/27/2017] [Indexed: 11/28/2022]
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Abstract
Genetic mouse models mimicking human diseases have been developed and utilized for retinal research in various topics, involving anatomy, physiology, biochemistry, and pathology. The main reasons why mouse models are important for retinal research include that rodents share a key retinal homology with humans and that genetic manipulation is relatively easily applicable for mice. Here, we describe genetic mouse models, which are categorized with functions in the retina and relationship with human diseases.
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Affiliation(s)
- Akiko Maeda
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Tadao Maeda
- Research Division, Kobe Research Institute, HEALIOS K.K., Kobe, Japan.
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Das RG, Marinho FP, Iwabe S, Santana E, McDaid KS, Aguirre GD, Miyadera K. Variabilities in retinal function and structure in a canine model of cone-rod dystrophy associated with RPGRIP1 support multigenic etiology. Sci Rep 2017; 7:12823. [PMID: 28993665 PMCID: PMC5634483 DOI: 10.1038/s41598-017-13112-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 09/13/2017] [Indexed: 01/01/2023] Open
Abstract
Defects in the cilia gene RPGRIP1 cause Leber congenital amaurosis and cone-rod dystrophy in humans. A form of canine cone-rod dystrophy (cord1) was originally associated with a homozygous insertion in RPGRIP1 (RPGRIP1ins/ins) as the primary disease locus while a homozygous deletion in MAP9 (MAP9del/del) was later identified as a modifier associated with the early onset form. However, we find further variability in cone electroretinograms (ERGs) ranging from normal to absent in an extended RPGRIP1ins/ins canine colony, irrespective of the MAP9 genotype. Ophthalmoscopically, cone ERGabsentRPGRIP1ins/ins eyes show discolouration of the tapetal fundus with varying onset and disease progression, while sd-OCT reveals atrophic changes. Despite marked changes in cone ERG and retinal morphology, photopic vision-guided behaviour is comparable between normal and cone ERGabsentRPGRIP1ins/ins littermates. Cone morphology of the dogs lacking cone ERG are truncated with shortened outer and inner segments. Immunohistochemically, cone ERGabsentRPGRIP1ins/ins retinas have extensive L/M-opsin mislocalization, lack CNGB3 labelling in the L/M-cones, and lack GC1 in all cones. Our results indicate that cord1 is a multigenic disease in which mutations in neither RPGRIP1 nor MAP9 alone lead to visual deficits, and additional gene(s) contribute to cone-specific functional and morphologic defects.
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Affiliation(s)
- Rueben G Das
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Felipe Pompeo Marinho
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Simone Iwabe
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Evelyn Santana
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Kendra Sierra McDaid
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Gustavo D Aguirre
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Keiko Miyadera
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Iribarne M, Masai I. Neurotoxicity of cGMP in the vertebrate retina: from the initial research on rd mutant mice to zebrafish genetic approaches. J Neurogenet 2017; 31:88-101. [PMID: 28812418 DOI: 10.1080/01677063.2017.1358268] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Zebrafish are an excellent animal model for research on vertebrate development and human diseases. Sophisticated genetic tools including large-scale mutagenesis methodology make zebrafish useful for studying neuronal degenerative diseases. Here, we review zebrafish models of inherited ophthalmic diseases, focusing on cGMP metabolism in photoreceptors. cGMP is the second messenger of phototransduction, and abnormal cGMP levels are associated with photoreceptor death. cGMP concentration represents a balance between cGMP phosphodiesterase 6 (PDE6) and guanylate cyclase (GC) activities in photoreceptors. Various zebrafish cGMP metabolism mutants were used to clarify molecular mechanisms by which dysfunctions in this pathway trigger photoreceptor degeneration. Here, we review the history of research on the retinal degeneration (rd) mutant mouse, which carries a genetic mutation of PDE6b, and we also highlight recent research in photoreceptor degeneration using zebrafish models. Several recent discoveries that provide insight into cGMP toxicity in photoreceptors are discussed.
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Affiliation(s)
- Maria Iribarne
- a Okinawa Institute of Science and Technology Graduate University , Onna, Okinawa , Japan
| | - Ichiro Masai
- a Okinawa Institute of Science and Technology Graduate University , Onna, Okinawa , Japan
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41
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Agrawal SA, Burgoyne T, Eblimit A, Bellingham J, Parfitt DA, Lane A, Nichols R, Asomugha C, Hayes MJ, Munro PM, Xu M, Wang K, Futter CE, Li Y, Chen R, Cheetham ME. REEP6 deficiency leads to retinal degeneration through disruption of ER homeostasis and protein trafficking. Hum Mol Genet 2017; 26:2667-2677. [PMID: 28475715 PMCID: PMC5808736 DOI: 10.1093/hmg/ddx149] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 01/09/2023] Open
Abstract
Retinitis pigmentosa (RP) is the most common form of inherited retinal dystrophy. We recently identified mutations in REEP6, which encodes the receptor expression enhancing protein 6, in several families with autosomal recessive RP. REEP6 is related to the REEP and Yop1p family of ER shaping proteins and potential receptor accessory proteins, but the role of REEP6 in the retina is unknown. Here we characterize the disease mechanisms associated with loss of REEP6 function using a Reep6 knockout mouse generated by CRISPR/Cas9 gene editing. In control mice REEP6 was localized to the inner segment and outer plexiform layer of rod photoreceptors. The Reep6-/- mice exhibited progressive photoreceptor degeneration from P20 onwards. Ultrastructural analyses at P20 by transmission electron microscopy and 3View serial block face scanning EM revealed an expansion of the distal ER in the Reep6-/- rods and an increase in their number of mitochondria. Electroretinograms revealed photoreceptor dysfunction preceded degeneration, suggesting potential defects in phototransduction. There was no effect on the traffic of rhodopsin, Rom1 or peripherin/rds; however, the retinal guanylate cyclases GC1 and GC2 were severely affected in the Reep6 knockout animals, with almost undetectable expression. These changes correlated with an increase in C/EBP homologous protein (CHOP) expression and the activation of caspase 12, suggesting that ER stress contributes to cell death. Collectively, these data suggest that REEP6 plays an essential role in maintaining cGMP homeostasis though facilitating the stability and/or trafficking of guanylate cyclases and maintaining ER and mitochondrial homeostasis.
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Affiliation(s)
- Smriti A. Agrawal
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Thomas Burgoyne
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Aiden Eblimit
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - James Bellingham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - David A. Parfitt
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Amelia Lane
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | | | - Chinwe Asomugha
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Matthew J. Hayes
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Peter M. Munro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Mingchu Xu
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Keqing Wang
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Clare E. Futter
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Yumei Li
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Rui Chen
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
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Iribarne M, Nishiwaki Y, Nakamura S, Araragi M, Oguri E, Masai I. Aipl1 is required for cone photoreceptor function and survival through the stability of Pde6c and Gc3 in zebrafish. Sci Rep 2017; 7:45962. [PMID: 28378769 PMCID: PMC5381001 DOI: 10.1038/srep45962] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 03/07/2017] [Indexed: 12/18/2022] Open
Abstract
Genetic mutations in aryl hydrocarbon receptor interacting protein-like 1 (AIPL1) cause photoreceptor degeneration associated with Leber congenital amaurosis 4 (LCA4) in human patients. Here we report retinal phenotypes of a zebrafish aipl1 mutant, gold rush (gosh). In zebrafish, there are two aipl1 genes, aipl1a and aipl1b, which are expressed mainly in rods and cones, respectively. The gosh mutant gene encodes cone-specific aipl1, aipl1b. Cone photoreceptors undergo progressive degeneration in the gosh mutant, indicating that aipl1b is required for cone survival. Furthermore, the cone-specific subunit of cGMP phosphodiesterase 6 (Pde6c) is markedly decreased in the gosh mutant, and the gosh mutation genetically interacts with zebrafish pde6c mutation eclipse (els). These data suggest that Aipl1 is required for Pde6c stability and function. In addition to Pde6c, we found that zebrafish cone-specific guanylate cyclase, zGc3, is also decreased in the gosh and els mutants. Furthermore, zGc3 knockdown embryos showed a marked reduction in Pde6c. These observations illustrate the interdependence of cGMP metabolism regulators between Aipl1, Pde6c, and Gc3 in photoreceptors.
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Affiliation(s)
- Maria Iribarne
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
| | - Yuko Nishiwaki
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
| | - Shohei Nakamura
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
| | - Masato Araragi
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
| | - Eri Oguri
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
| | - Ichiro Masai
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
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43
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Boye SL, Olshevskaya EV, Peshenko IV, McCullough KT, Boye SE, Dizhoor AM. Functional study of two biochemically unusual mutations in GUCY2D Leber congenital amaurosis expressed via adenoassociated virus vector in mouse retinas. Mol Vis 2016; 22:1342-1351. [PMID: 27881908 PMCID: PMC5108460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/08/2016] [Indexed: 11/03/2022] Open
Abstract
PURPOSE To test, in living photoreceptors, two mutations, S248W and R1091x, in the GUCY2D gene linked to Leber congenital amaurosis 1 (LCA1) that fail to inactivate the catalytic activity of a heterologously expressed retinal membrane guanylyl cyclase 1 (RetGC1). METHODS GUC2YD cDNA constructs coding for wild-type human (hWT), R1091x, and S248W GUCY2D under the control of the human rhodopsin kinase promoter were expressed in Gucy2e-/-Gucy2f-/- knockout (GCdKO) mouse retinas, which lack endogenous RetGC activity. The constructs were delivered via subretinally injected adenoassociated virus (AAV) vector in one eye, leaving the opposite eye as the non-injected negative control. After testing with electroretinography (ERG), the retinas extracted from the AAV-treated and control eyes were used in guanylyl cyclase activity assays, immunoblotting, and anti-RetGC1 immunofluorescence staining. RESULTS Cyclase activity in retinas treated with either hWT or R1091x GUCY2D transgenes was similar but was undetectable in the S248W GUCY2D-treated retinas, which starkly contrasts their relative activities when heterologously expressed in human embryonic kidney (HEK293) cells. Rod and cone ERGs, absent in GCdKO, appeared in the hWT and R1091x GUCY2D-injected eyes, while the S248W mutant failed to restore scotopic ERG response and enabled only rudimentary photopic ERG response. The hWT and R1091x GUCY2D immunofluorescence was robust in the rod and cone outer segments, whereas the S248W was detectable only in the sparse cone outer segments and sporadic photoreceptor cell bodies. Robust RetGC1 expression was detected with immunoblotting in the hWT and R1091x-treated retinas but was marginal at best in the S248W GUCY2D retinas, despite the confirmed presence of the S248W GUCY2D transcripts. CONCLUSIONS The phenotype of S248W GUCY2D in living retinas did not correlate with the previously described normal biochemical activity of this mutant when heterologously expressed in non-photoreceptor cell culture. This result suggests that the S248W mutation contributes to LCA1 by hampering the expression, processing, and/or cellular transport of GUCY2D, rather than its enzymatic properties. In contrast, the effective restoration of rod and cone function by R1091x GUCY2D is paradoxical and does not explain the severe loss of vision typical for LCA1 associated with that mutant allele.
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Affiliation(s)
- Sanford L. Boye
- Department of Ophthalmology, University of Florida, Gainesville, FL
| | | | - Igor V. Peshenko
- Pennsylvania College of Optometry, Salus University, Elkins Park, PA
| | | | - Shannon E. Boye
- Department of Ophthalmology, University of Florida, Gainesville, FL
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Sharma RK, Duda T, Makino CL. Integrative Signaling Networks of Membrane Guanylate Cyclases: Biochemistry and Physiology. Front Mol Neurosci 2016; 9:83. [PMID: 27695398 PMCID: PMC5023690 DOI: 10.3389/fnmol.2016.00083] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/29/2016] [Indexed: 12/24/2022] Open
Abstract
This monograph presents a historical perspective of cornerstone developments on the biochemistry and physiology of mammalian membrane guanylate cyclases (MGCs), highlighting contributions made by the authors and their collaborators. Upon resolution of early contentious studies, cyclic GMP emerged alongside cyclic AMP, as an important intracellular second messenger for hormonal signaling. However, the two signaling pathways differ in significant ways. In the cyclic AMP pathway, hormone binding to a G protein coupled receptor leads to stimulation or inhibition of an adenylate cyclase, whereas the cyclic GMP pathway dispenses with intermediaries; hormone binds to an MGC to affect its activity. Although the cyclic GMP pathway is direct, it is by no means simple. The modular design of the molecule incorporates regulation by ATP binding and phosphorylation. MGCs can form complexes with Ca2+-sensing subunits that either increase or decrease cyclic GMP synthesis, depending on subunit identity. In some systems, co-expression of two Ca2+ sensors, GCAP1 and S100B with ROS-GC1 confers bimodal signaling marked by increases in cyclic GMP synthesis when intracellular Ca2+ concentration rises or falls. Some MGCs monitor or are modulated by carbon dioxide via its conversion to bicarbonate. One MGC even functions as a thermosensor as well as a chemosensor; activity reaches a maximum with a mild drop in temperature. The complexity afforded by these multiple limbs of operation enables MGC networks to perform transductions traditionally reserved for G protein coupled receptors and Transient Receptor Potential (TRP) ion channels and to serve a diverse array of functions, including control over cardiac vasculature, smooth muscle relaxation, blood pressure regulation, cellular growth, sensory transductions, neural plasticity and memory.
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Affiliation(s)
- Rameshwar K Sharma
- The Unit of Regulatory and Molecular Biology, Research Divisions of Biochemistry and Molecular Biology, Salus University Elkins Park, PA, USA
| | - Teresa Duda
- The Unit of Regulatory and Molecular Biology, Research Divisions of Biochemistry and Molecular Biology, Salus University Elkins Park, PA, USA
| | - Clint L Makino
- Department of Physiology and Biophysics, Boston University School of Medicine Boston, MA, USA
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45
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Peshenko IV, Olshevskaya EV, Dizhoor AM. Functional Study and Mapping Sites for Interaction with the Target Enzyme in Retinal Degeneration 3 (RD3) Protein. J Biol Chem 2016; 291:19713-23. [PMID: 27471269 DOI: 10.1074/jbc.m116.742288] [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] [Indexed: 12/24/2022] Open
Abstract
Retinal degeneration 3 (RD3) protein, essential for normal expression of retinal membrane guanylyl cyclase (RetGC) in photoreceptor cells, blocks RetGC catalytic activity and stimulation by guanylyl cyclase-activating proteins (GCAPs). In a mouse retina, RD3 inhibited both RetGC1 and RetGC2 isozymes. Photoreceptors in the rd3/rd3 mouse retinas lacking functional RD3 degenerated more severely than in the retinas lacking both RetGC isozymes, consistent with a hypothesis that the inhibitory activity of RD3 has a functional role in photoreceptors. To map the potential target-binding site(s) on RD3, short evolutionary conserved regions of its primary structure were scrambled and the mutations were tested for the RD3 ability to inhibit RetGC1 and co-localize with the cyclase in co-transfected cells. Substitutions in 4 out of 22 tested regions, (87)KIHP(90), (93)CGPAI(97), (99)RFRQ(102), and (119)RSVL(122), reduced the RD3 apparent affinity for the cyclase 180-700-fold. Changes of amino acid sequences outside the Lys(87)-Leu(122) central portion of the molecule either failed to prevent RD3 binding to the cyclase or had a much smaller effect. Mutations in the (93)CGPAI(97) portion of a predicted central α-helix most drastically suppressed the inhibitory activity of RD3 and disrupted RD3 co-localization with RetGC1 in HEK293 cells. Different side chains replacing Cys(93) profoundly reduced RD3 affinity for the cyclase, irrespective of their relative helix propensities. We conclude that the main RetGC-binding interface on RD3 required for the negative regulation of the cyclase localizes to the Lys(87)-Leu(122) region.
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Affiliation(s)
- Igor V Peshenko
- From the Pennsylvania College of Optometry, Department of Research, Salus University, Elkins Park, Pennsylvania 19027
| | - Elena V Olshevskaya
- From the Pennsylvania College of Optometry, Department of Research, Salus University, Elkins Park, Pennsylvania 19027
| | - Alexander M Dizhoor
- From the Pennsylvania College of Optometry, Department of Research, Salus University, Elkins Park, Pennsylvania 19027
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46
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Ingram NT, Sampath AP, Fain GL. Why are rods more sensitive than cones? J Physiol 2016; 594:5415-26. [PMID: 27218707 DOI: 10.1113/jp272556] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 05/16/2016] [Indexed: 12/11/2022] Open
Abstract
One hundred and fifty years ago Max Schultze first proposed the duplex theory of vision, that vertebrate eyes have two types of photoreceptor cells with differing sensitivity: rods for dim light and cones for bright light and colour detection. We now know that this division is fundamental not only to the photoreceptors themselves but to the whole of retinal and visual processing. But why are rods more sensitive, and how did the duplex retina first evolve? Cells resembling cones are very old, first appearing among cnidarians; the emergence of rods was a key step in the evolution of the vertebrate eye. Many transduction proteins have different isoforms in rods and cones, and others are expressed at different levels. Moreover rods and cones have a different anatomy, with only rods containing membranous discs enclosed by the plasma membrane. These differences must be responsible for the difference in absolute sensitivity, but which are essential? Recent research particularly expressing cone proteins in rods or changing the level of expression seem to show that many of the molecular differences in the activation and decay of the response may have each made a small contribution as evolution proceeded stepwise with incremental increases in sensitivity. Rod outer-segment discs were not essential and developed after single-photon detection. These experiments collectively provide a new understanding of the two kinds of photoreceptors and help to explain how gene duplication and the formation of rod-specific proteins produced the duplex retina, which has remained remarkably constant in physiology from amphibians to man.
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Affiliation(s)
- Norianne T Ingram
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, 90095-7239, USA
| | - Alapakkam P Sampath
- Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, CA, 90095-7000, USA
| | - Gordon L Fain
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, 90095-7239, USA. .,Department of Ophthalmology and Jules Stein Eye Institute, University of California, Los Angeles, CA, 90095-7000, USA.
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47
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Abstract
cGMP controls many cellular functions ranging from growth, viability, and differentiation to contractility, secretion, and ion transport. The mammalian genome encodes seven transmembrane guanylyl cyclases (GCs), GC-A to GC-G, which mainly modulate submembrane cGMP microdomains. These GCs share a unique topology comprising an extracellular domain, a short transmembrane region, and an intracellular COOH-terminal catalytic (cGMP synthesizing) region. GC-A mediates the endocrine effects of atrial and B-type natriuretic peptides regulating arterial blood pressure/volume and energy balance. GC-B is activated by C-type natriuretic peptide, stimulating endochondral ossification in autocrine way. GC-C mediates the paracrine effects of guanylins on intestinal ion transport and epithelial turnover. GC-E and GC-F are expressed in photoreceptor cells of the retina, and their activation by intracellular Ca(2+)-regulated proteins is essential for vision. Finally, in the rodent system two olfactorial GCs, GC-D and GC-G, are activated by low concentrations of CO2and by peptidergic (guanylins) and nonpeptidergic odorants as well as by coolness, which has implications for social behaviors. In the past years advances in human and mouse genetics as well as the development of sensitive biosensors monitoring the spatiotemporal dynamics of cGMP in living cells have provided novel relevant information about this receptor family. This increased our understanding of the mechanisms of signal transduction, regulation, and (dys)function of the membrane GCs, clarified their relevance for genetic and acquired diseases and, importantly, has revealed novel targets for therapies. The present review aims to illustrate these different features of membrane GCs and the main open questions in this field.
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Affiliation(s)
- Michaela Kuhn
- Institute of Physiology, University of Würzburg, Würzburg, Germany
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48
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A Mini-review: Animal Models of GUCY2D Leber Congenital Amaurosis (LCA1). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:253-8. [PMID: 26427419 DOI: 10.1007/978-3-319-17121-0_34] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
GUCY2D encodes retinal guanylate cylase-1 (retGC1), a protein that plays a pivotal role in the recovery phase of phototransduction. Mutations in GUCY2D are associated with a leading cause of recessive Leber congenital amaurosis (LCA1). Patients present within the first year of life with aberrant or unrecordable electroretinogram (ERG), nystagmus and a relatively normal fundus. Aside from abnormalities in the outer segments of foveal cones and, in some patients, foveal cone loss, LCA1 patients retain normal retinal laminar architecture suggesting they may be good candidates for gene replacement therapy. Several animal models of LCA1, both naturally occurring and engineered, have been characterized and provide valuable tools for translational studies. This mini-review will summarize the phenotypes of these models and describe how each has been instrumental in proof of concept studies to develop a gene replacement therapy for GUCY2D-LCA1.
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49
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Pearring JN, Spencer WJ, Lieu EC, Arshavsky VY. Guanylate cyclase 1 relies on rhodopsin for intracellular stability and ciliary trafficking. eLife 2015; 4. [PMID: 26590321 PMCID: PMC4709261 DOI: 10.7554/elife.12058] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 11/20/2015] [Indexed: 01/21/2023] Open
Abstract
Sensory cilia are populated by a select group of signaling proteins that detect environmental stimuli. How these molecules are delivered to the sensory cilium and whether they rely on one another for specific transport remains poorly understood. Here, we investigated whether the visual pigment, rhodopsin, is critical for delivering other signaling proteins to the sensory cilium of photoreceptor cells, the outer segment. Rhodopsin is the most abundant outer segment protein and its proper transport is essential for formation of this organelle, suggesting that such a dependency might exist. Indeed, we demonstrated that guanylate cyclase-1, producing the cGMP second messenger in photoreceptors, requires rhodopsin for intracellular stability and outer segment delivery. We elucidated this dependency by showing that guanylate cyclase-1 is a novel rhodopsin-binding protein. These findings expand rhodopsin's role in vision from being a visual pigment and major outer segment building block to directing trafficking of another key signaling protein.
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Affiliation(s)
- Jillian N Pearring
- Department of Ophthalmology, Duke University Medical Center, Durham, United States
| | - William J Spencer
- Department of Ophthalmology, Duke University Medical Center, Durham, United States.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, United States
| | - Eric C Lieu
- Department of Ophthalmology, Duke University Medical Center, Durham, United States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, United States.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, United States
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50
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Koch KW, Dell'Orco D. Protein and Signaling Networks in Vertebrate Photoreceptor Cells. Front Mol Neurosci 2015; 8:67. [PMID: 26635520 PMCID: PMC4646965 DOI: 10.3389/fnmol.2015.00067] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/26/2015] [Indexed: 01/10/2023] Open
Abstract
Vertebrate photoreceptor cells are exquisite light detectors operating under very dim and bright illumination. The photoexcitation and adaptation machinery in photoreceptor cells consists of protein complexes that can form highly ordered supramolecular structures and control the homeostasis and mutual dependence of the secondary messengers cyclic guanosine monophosphate (cGMP) and Ca2+. The visual pigment in rod photoreceptors, the G protein-coupled receptor rhodopsin is organized in tracks of dimers thereby providing a signaling platform for the dynamic scaffolding of the G protein transducin. Illuminated rhodopsin is turned off by phosphorylation catalyzed by rhodopsin kinase (GRK1) under control of Ca2+-recoverin. The GRK1 protein complex partly assembles in lipid raft structures, where shutting off rhodopsin seems to be more effective. Re-synthesis of cGMP is another crucial step in the recovery of the photoresponse after illumination. It is catalyzed by membrane bound sensory guanylate cyclases (GCs) and is regulated by specific neuronal Ca2+-sensor proteins called guanylate cyclase-activating proteins (GCAPs). At least one GC (ROS-GC1) was shown to be part of a multiprotein complex having strong interactions with the cytoskeleton and being controlled in a multimodal Ca2+-dependent fashion. The final target of the cGMP signaling cascade is a cyclic nucleotide-gated (CNG) channel that is a hetero-oligomeric protein located in the plasma membrane and interacting with accessory proteins in highly organized microdomains. We summarize results and interpretations of findings related to the inhomogeneous organization of signaling units in photoreceptor outer segments.
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Affiliation(s)
- Karl-Wilhelm Koch
- Department of Neurosciences, Biochemistry Group, University of Oldenburg Oldenburg, Germany
| | - Daniele Dell'Orco
- Department of Neurological, Biomedical and Movement Sciences, Section of Biological Chemistry and Center for BioMedical Computing (CBMC), University of Verona Verona, Italy
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