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Razzaghi N, Fernandez-Gonzalez P, Mas-Sanchez A, Vila-Julià G, Perez JJ, Garriga P. Effect of Sodium Valproate on the Conformational Stability of the Visual G Protein-Coupled Receptor Rhodopsin. Molecules 2021; 26:molecules26103032. [PMID: 34069614 PMCID: PMC8160834 DOI: 10.3390/molecules26103032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 12/29/2022] Open
Abstract
Rhodopsin is the G protein-coupled receptor of rod photoreceptor cells that mediates vertebrate vision at low light intensities. Mutations in rhodopsin cause inherited retinal degenerative diseases such as retinitis pigmentosa. Several therapeutic strategies have attempted to address and counteract the deleterious effect of rhodopsin mutations on the conformation and function of this photoreceptor protein, but none has been successful in efficiently preventing retinal degeneration in humans. These approaches include, among others, the use of small molecules, known as pharmacological chaperones, that bind to the receptor stabilizing its proper folded conformation. Valproic acid, in its sodium valproate form, has been used as an anticonvulsant in epileptic patients and in the treatment of several psychiatric disorders. More recently, this compound has been tested as a potential therapeutic agent for the treatment of retinal degeneration associated with retinitis pigmentosa caused by rhodopsin mutations. We now report on the effect of sodium valproate on the conformational stability of heterologously expressed wild-type rhodopsin and a rhodopsin mutant, I307N, which has been shown to be an appropriate model for studying retinal degeneration in mice. We found no sign of enhanced stability for the dark inactive conformation of the I307N mutant. Furthermore, the photoactivated conformation of the mutant appears to be destabilized by sodium valproate as indicated by a faster decay of its active conformation. Therefore, our results support a destabilizing effect of sodium valproate on rhodopsin I307N mutant associated with retinal degeneration. These findings, at the molecular level, agree with recent clinical studies reporting negative effects of sodium valproate on the visual function of retinitis pigmentosa patients.
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Affiliation(s)
- Neda Razzaghi
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Universitat Politècnica de Catalunya-Barcelona Tech, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Spain; (N.R.); (P.F.-G.); (A.M.-S.)
| | - Pol Fernandez-Gonzalez
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Universitat Politècnica de Catalunya-Barcelona Tech, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Spain; (N.R.); (P.F.-G.); (A.M.-S.)
| | - Aina Mas-Sanchez
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Universitat Politècnica de Catalunya-Barcelona Tech, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Spain; (N.R.); (P.F.-G.); (A.M.-S.)
| | - Guillem Vila-Julià
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Universitat Politècnica de Catalunya-Barcelona Tech., Avinguda Diagonal, 647, 08028 Barcelona, Spain; (G.V.-J.); (J.J.P.)
| | - Juan Jesus Perez
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Universitat Politècnica de Catalunya-Barcelona Tech., Avinguda Diagonal, 647, 08028 Barcelona, Spain; (G.V.-J.); (J.J.P.)
| | - Pere Garriga
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Universitat Politècnica de Catalunya-Barcelona Tech, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Spain; (N.R.); (P.F.-G.); (A.M.-S.)
- Correspondence:
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102
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Khelashvili G, Pillai AN, Lee J, Pandey K, Payne AM, Siegel Z, Cuendet MA, Lewis TR, Arshavsky VY, Broichhagen J, Levitz J, Menon AK. Unusual mode of dimerization of retinitis pigmentosa-associated F220C rhodopsin. Sci Rep 2021; 11:10536. [PMID: 34006992 PMCID: PMC8131606 DOI: 10.1038/s41598-021-90039-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/29/2021] [Indexed: 12/30/2022] Open
Abstract
Mutations in the G protein-coupled receptor (GPCR) rhodopsin are a common cause of autosomal dominant retinitis pigmentosa, a blinding disease. Rhodopsin self-associates in the membrane, and the purified monomeric apo-protein opsin dimerizes in vitro as it transitions from detergent micelles to reconstitute into a lipid bilayer. We previously reported that the retinitis pigmentosa-linked F220C opsin mutant fails to dimerize in vitro, reconstituting as a monomer. Using fluorescence-based assays and molecular dynamics simulations we now report that whereas wild-type and F220C opsin display distinct dimerization propensities in vitro as previously shown, they both dimerize in the plasma membrane of HEK293 cells. Unexpectedly, molecular dynamics simulations show that F220C opsin forms an energetically favored dimer in the membrane when compared with the wild-type protein. The conformation of the F220C dimer is unique, with transmembrane helices 5 and 6 splayed apart, promoting widening of the intracellular vestibule of each protomer and influx of water into the protein interior. FRET experiments with SNAP-tagged wild-type and F220C opsin expressed in HEK293 cells are consistent with this conformational difference. We speculate that the unusual mode of dimerization of F220C opsin in the membrane may have physiological consequences.
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Affiliation(s)
- George Khelashvili
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, 10065, USA.
- Institute of Computational Biomedicine, Weill Cornell Medical College, New York, NY, 10065, USA.
| | | | - Joon Lee
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Kalpana Pandey
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Alexander M Payne
- Tri-Institutional PhD Program in Chemical Biology, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Zarek Siegel
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA, 92093, USA
| | - Michel A Cuendet
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, 10065, USA
- Ludwig Institute for Cancer Research, University of Lausanne, Lausanne, Switzerland
- Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, 1015, Lausanne, Switzerland
| | - Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Johannes Broichhagen
- Leibniz-Forschungsinstitut Für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA.
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA.
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103
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Chuon K, Kim SY, Meas S, Shim JG, Cho SG, Kang KW, Kim JH, Cho HS, Jung KH. Assembly of Natively Synthesized Dual Chromophores Into Functional Actinorhodopsin. Front Microbiol 2021; 12:652328. [PMID: 33995310 PMCID: PMC8113403 DOI: 10.3389/fmicb.2021.652328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/06/2021] [Indexed: 12/18/2022] Open
Abstract
Microbial rhodopsin is a simple solar energy-capturing molecule compared to the complex photosynthesis apparatus. Light-driven proton pumping across the cell membrane is a crucial mechanism underlying microbial energy production. Actinobacteria is one of the highly abundant bacterial phyla in freshwater habitats, and members of this lineage are considered to boost heterotrophic growth via phototrophy, as indicated by the presence of actino-opsin (ActR) genes in their genome. However, it is difficult to validate their function under laboratory settings because Actinobacteria are not consistently cultivable. Based on the published genome sequence of Candidatus aquiluna sp. strain IMCC13023, actinorhodopsin from the strain (ActR-13023) was isolated and characterized in this study. Notably, ActR-13023 assembled with natively synthesized carotenoid/retinal (used as a dual chromophore) and functioned as a light-driven outward proton pump. The ActR-13023 gene and putative genes involved in the chromophore (retinal/carotenoid) biosynthetic pathway were detected in the genome, indicating the functional expression ActR-13023 under natural conditions for the utilization of solar energy for proton translocation. Heterologous expressed ActR-13023 exhibited maximum absorption at 565 nm with practical proton pumping ability. Purified ActR-13023 could be reconstituted with actinobacterial carotenoids for additional light-harvesting. The existence of actinorhodopsin and its chromophore synthesis machinery in Actinobacteria indicates the inherent photo-energy conversion function of this microorganism. The assembly of ActR-13023 to its synthesized chromophores validated the microbial community's importance in the energy cycle.
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Affiliation(s)
- Kimleng Chuon
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - So Young Kim
- Research Institute of Basic Sciences, Seoul National University, Seoul, South Korea
| | - Seanghun Meas
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Jin-Gon Shim
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Shin-Gyu Cho
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Kun-Wook Kang
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Ji-Hyun Kim
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Hyun-Suk Cho
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Kwang-Hwan Jung
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
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104
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Takatani N, Beppu F, Yamano Y, Maoka T, Hosokawa M. Seco-type β-Apocarotenoid Generated by β-Carotene Oxidation Exerts Anti-inflammatory Effects against Activated Macrophages. J Oleo Sci 2021; 70:549-558. [PMID: 33692243 DOI: 10.5650/jos.ess20329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
β-Apocarotenoids are the cleavage products of β-carotene. They are found in plants, carotenoid-containing foods, and animal tissues. However, limited information is available regarding the health benefits of β-apocarotenoids. Here, we prepared seco-type β-apocarotenoids through the chemical oxidation of β-carotene and investigated their anti-inflammatory effects against activated macrophages. Oxidation of β-carotene with potassium permanganate produced seco-β-apo-8'-carotenal, in which one end-group formed an "open" β-ring and the other was cleaved at the C-7',8' position. In lipopolysaccharide-stimulated murine macrophage-like RAW264.7 cells, seco-β-apo-8'-carotenal inhibited the secretion and mRNA expression of inflammatory mediators such as nitric oxide, interleukin (IL)-6 and IL-1β, and monocyte chemoattractant protein-1. Furthermore, seco-β-apo-8'-carotenal suppressed phosphorylation of c-Jun N-terminal kinase and the inhibitor of nuclear factor (NF)-κB as well as the nuclear accumulation of NF-κB p65. Notably, since seco-β-apo-8'-carotenal exhibited remarkable anti-inflammatory activity compared with β-apo-8'-carotenal, its anti-inflammatory action could depend on the opened β-ring structure. These results suggest that seco-β-apo-8'-carotenal has high potential for the prevention of inflammation-related diseases.
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Affiliation(s)
| | | | - Yumiko Yamano
- Laboratory of Organic Chemistry for Life Science, Kobe Pharmaceutical University
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105
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Fanelli F, Felline A, Marigo V. Structural aspects of rod opsin and their implication in genetic diseases. Pflugers Arch 2021; 473:1339-1359. [PMID: 33728518 DOI: 10.1007/s00424-021-02546-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/17/2021] [Accepted: 02/22/2021] [Indexed: 01/04/2023]
Abstract
Vision in dim-light conditions is triggered by photoactivation of rhodopsin, the visual pigment of rod photoreceptor cells. Rhodopsin is made of a protein, the G protein coupled receptor (GPCR) opsin, and the chromophore 11-cis-retinal. Vertebrate rod opsin is the GPCR best characterized at the atomic level of detail. Since the release of the first crystal structure 20 years ago, a huge number of structures have been released that, in combination with valuable spectroscopic determinations, unveiled most aspects of the photobleaching process. A number of spontaneous mutations of rod opsin have been found linked to vision-impairing diseases like autosomal dominant or autosomal recessive retinitis pigmentosa (adRP or arRP, respectively) and autosomal congenital stationary night blindness (adCSNB). While adCSNB is mainly caused by constitutive activation of rod opsin, RP shows more variegate determinants affecting different aspects of rod opsin function. The vast majority of missense rod opsin mutations affects folding and trafficking and is linked to adRP, an incurable disease that awaits light on its molecular structure determinants. This review article summarizes all major structural information available on vertebrate rod opsin conformational states and the insights gained so far into the structural determinants of adCSNB and adRP linked to rod opsin mutations. Strategies to design small chaperones with therapeutic potential for selected adRP rod opsin mutants will be discussed as well.
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Affiliation(s)
- Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125, Modena, Italy. .,Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, via Campi 287, Modena, 41125, Italy.
| | - Angelo Felline
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125, Modena, Italy
| | - Valeria Marigo
- Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, via Campi 287, Modena, 41125, Italy.,Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125, Modena, Italy
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106
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Abreu N, Levitz J. Optogenetic Techniques for Manipulating and Sensing G Protein-Coupled Receptor Signaling. Methods Mol Biol 2021; 2173:21-51. [PMID: 32651908 DOI: 10.1007/978-1-0716-0755-8_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
G protein-coupled receptors (GPCRs) form the largest class of membrane receptors in the mammalian genome with nearly 800 human genes encoding for unique subtypes. Accordingly, GPCR signaling is implicated in nearly all physiological processes. However, GPCRs have been difficult to study due in part to the complexity of their function which can lead to a plethora of converging or diverging downstream effects over different time and length scales. Classic techniques such as pharmacological control, genetic knockout and biochemical assays often lack the precision required to probe the functions of specific GPCR subtypes. Here we describe the rapidly growing set of optogenetic tools, ranging from methods for optical control of the receptor itself to optical sensing and manipulation of downstream effectors. These tools permit the quantitative measurements of GPCRs and their downstream signaling with high specificity and spatiotemporal precision.
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Affiliation(s)
- Nohely Abreu
- Biochemistry, Cell and Molecular Biology Graduate Program, Weill Cornell Medicine, New York, NY, USA
| | - Joshua Levitz
- Biochemistry, Cell and Molecular Biology Graduate Program, Weill Cornell Medicine, New York, NY, USA.
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA.
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107
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Choi EH, Daruwalla A, Suh S, Leinonen H, Palczewski K. Retinoids in the visual cycle: role of the retinal G protein-coupled receptor. J Lipid Res 2021; 62:100040. [PMID: 32493732 PMCID: PMC7910522 DOI: 10.1194/jlr.tr120000850] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/20/2020] [Indexed: 12/13/2022] Open
Abstract
Driven by the energy of a photon, the visual pigments in rod and cone photoreceptor cells isomerize 11-cis-retinal to the all-trans configuration. This photochemical reaction initiates the signal transduction pathway that eventually leads to the transmission of a visual signal to the brain and leaves the opsins insensitive to further light stimulation. For the eye to restore light sensitivity, opsins require recharging with 11-cis-retinal. This trans-cis back conversion is achieved through a series of enzymatic reactions composing the retinoid (visual) cycle. Although it is evident that the classical retinoid cycle is critical for vision, the existence of an adjunct pathway for 11-cis-retinal regeneration has been debated for many years. Retinal pigment epithelium (RPE)-retinal G protein-coupled receptor (RGR) has been identified previously as a mammalian retinaldehyde photoisomerase homologous to retinochrome found in invertebrates. Using pharmacological, genetic, and biochemical approaches, researchers have now established the physiological relevance of the RGR in 11-cis-retinal regeneration. The photoisomerase activity of RGR in the RPE and Müller glia explains how the eye can remain responsive in daylight. In this review, we will focus on retinoid metabolism in the eye and visual chromophore regeneration mediated by RGR.
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Affiliation(s)
- Elliot H Choi
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, University of California, Irvine, CA, USA; Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA.
| | - Anahita Daruwalla
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA; Departments of Physiology and Biophysics, and Chemistry, University of California, Irvine, CA, USA
| | - Susie Suh
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, University of California, Irvine, CA, USA; Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Henri Leinonen
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, University of California, Irvine, CA, USA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, University of California, Irvine, CA, USA; Departments of Physiology and Biophysics, and Chemistry, University of California, Irvine, CA, USA.
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108
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Bullock J, Polato F, Abu-Asab M, Bernardo-Colón A, Aflaki E, Agbaga MP, Becerra SP. Degradation of Photoreceptor Outer Segments by the Retinal Pigment Epithelium Requires Pigment Epithelium-Derived Factor Receptor (PEDF-R). Invest Ophthalmol Vis Sci 2021; 62:30. [PMID: 33605986 PMCID: PMC7900850 DOI: 10.1167/iovs.62.2.30] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/19/2021] [Indexed: 12/28/2022] Open
Abstract
Purpose To examine the contribution of pigment epithelium-derived factor receptor (PEDF-R) to the phagocytosis process. Previously, we identified PEDF-R, the protein encoded by the PNPLA2 gene, as a phospholipase A2 in the retinal pigment epithelium (RPE). During phagocytosis, RPE cells ingest abundant phospholipids and protein in the form of photoreceptor outer segment (POS) tips, which are then hydrolyzed. The role of PEDF-R in RPE phagocytosis is not known. Methods Mice in which PNPLA2 was conditionally knocked out (cKO) in the RPE were generated. Mouse RPE/choroid explants were cultured. Human ARPE-19 cells were transfected with siPNPLA2 silencing duplexes. POSs were isolated from bovine retinas. The phospholipase A2 inhibitor bromoenol lactone was used. Transmission electron microscopy, immunofluorescence, lipid labeling, pulse-chase experiments, western blots, and free fatty acid and β-hydroxybutyrate assays were performed. Results The RPE of the cKO mice accumulated lipids, as well as more abundant and larger rhodopsin particles, compared to littermate controls. Upon POS exposure, RPE explants from cKO mice released less β-hydroxybutyrate compared to controls. After POS ingestion during phagocytosis, rhodopsin degradation was stalled both in cells treated with bromoenol lactone and in PNPLA2-knocked-down cells relative to their corresponding controls. Phospholipase A2 inhibition lowered β-hydroxybutyrate release from phagocytic RPE cells. PNPLA2 knockdown also resulted in a decline in fatty acids and β-hydroxybutyrate release from phagocytic RPE cells. Conclusions PEDF-R downregulation delayed POS digestion during phagocytosis. The findings imply that the efficiency of RPE phagocytosis depends on PEDF-R, thus identifying a novel contribution of this protein to POS degradation in the RPE.
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Affiliation(s)
- Jeanee Bullock
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington DC, United States
| | - Federica Polato
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Mones Abu-Asab
- Section of Histopathology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Alexandra Bernardo-Colón
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Elma Aflaki
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Martin-Paul Agbaga
- Departments of Cell Biology and Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - S. Patricia Becerra
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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Guo Z, He X, Jiang C, Shi Y, Zhou N. Activation of Bombyx mori neuropeptide G protein-coupled receptor A19 by neuropeptide RYamides couples to G q protein-dependent signaling pathways. J Cell Biochem 2021; 122:456-471. [PMID: 33399233 DOI: 10.1002/jcb.29874] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 11/02/2020] [Accepted: 11/09/2020] [Indexed: 12/13/2022]
Abstract
RYamides constitute a novel family of neuropeptides newly identified in insects, and play important roles in regulating a variety of physiological processes. However, the signaling characteristics and physiological actions of RYamide signaling system remain largely unknown. In the present study, we cloned the full-length complementary DNA of the RYamide receptor BNGR-A19 from Bombyx mori larvae. After expression in mammalian HEK293T and insect Sf9 cells, functional assays revealed that BNGR-A19 was activated by synthetic RYamide peptides, triggering a significant increase in cAMP-response element controlled luciferase activity and Ca2+ mobilization in a Gq inhibitor-sensitive manner. Upon activation by RYamide peptides, BNGR-A19 elicited ERK1/2 phosphorylation via a Gq -PLC-PKC pathway, and also underwent a rapid internalization from the cell surface to the cytoplasm. Further cross-activity analysis indicated that BNGR-A19 exhibited very weak response upon stimulation by high concentration (1 μM) of Bombyx sulfakinin-1, neuropeptide F-1, and short neuropeptide F-1, and vice versa, Bombyx RYamides also showed slight potency for activating Bombyx NPF receptor (BNGR-A4) and sNPF receptor (BNGR-A11). In addition, the quantitative reverse-transcription polymerase chain reaction results showed that the high-level expression of BNGR-A19 was detected in the hindgut and testis, suggesting that the RYamide signaling is likely involved in the regulation of feeding, water homeostasis and testis development. This study provides the first in-depth information on the insect RYamide signaling system, facilitating the further clarification of its endocrinological roles in insect physiology.
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Affiliation(s)
- Zhiqiang Guo
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
| | - Xiaobai He
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
| | - Chaohui Jiang
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
| | - Ying Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
| | - Naiming Zhou
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
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110
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Kiser PD, Palczewski K. Pathways and disease-causing alterations in visual chromophore production for vertebrate vision. J Biol Chem 2021; 296:100072. [PMID: 33187985 PMCID: PMC7948990 DOI: 10.1074/jbc.rev120.014405] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
All that we view of the world begins with an ultrafast cis to trans photoisomerization of the retinylidene chromophore associated with the visual pigments of rod and cone photoreceptors. The continual responsiveness of these photoreceptors is then sustained by regeneration processes that convert the trans-retinoid back to an 11-cis configuration. Recent biochemical and electrophysiological analyses of the retinal G-protein-coupled receptor (RGR) suggest that it could sustain the responsiveness of photoreceptor cells, particularly cones, even under bright light conditions. Thus, two mechanisms have evolved to accomplish the reisomerization: one involving the well-studied retinoid isomerase (RPE65) and a second photoisomerase reaction mediated by the RGR. Impairments to the pathways that transform all-trans-retinal back to 11-cis-retinal are associated with mild to severe forms of retinal dystrophy. Moreover, with age there also is a decline in the rate of chromophore regeneration. Both pharmacological and genetic approaches are being used to bypass visual cycle defects and consequently mitigate blinding diseases. Rapid progress in the use of genome editing also is paving the way for the treatment of disparate retinal diseases. In this review, we provide an update on visual cycle biochemistry and then discuss visual-cycle-related diseases and emerging therapeutics for these disorders. There is hope that these advances will be helpful in treating more complex diseases of the eye, including age-related macular degeneration (AMD).
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Affiliation(s)
- Philip D Kiser
- The Department of Physiology & Biophysics, University of California, Irvine, California, USA; Research Service, The VA Long Beach Health Care System, Long Beach, California, USA; The Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California, USA.
| | - Krzysztof Palczewski
- The Department of Physiology & Biophysics, University of California, Irvine, California, USA; The Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California, USA; The Department of Chemistry, University of California, Irvine, California, USA.
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111
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Takatani N, Taya D, Katsuki A, Beppu F, Yamano Y, Wada A, Miyashita K, Hosokawa M. Identification of Paracentrone in Fucoxanthin-Fed Mice and Anti-Inflammatory Effect against Lipopolysaccharide-Stimulated Macrophages and Adipocytes. Mol Nutr Food Res 2020; 65:e2000405. [PMID: 33215789 DOI: 10.1002/mnfr.202000405] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/22/2020] [Indexed: 12/16/2022]
Abstract
SCOPE Fucoxanthin is converted to fucoxanthinol and amarouciaxanthin A in the mouse body. However, further metabolism such as cleavage products (i.e., apocarotenoids) remains unclear. The fucoxanthin-derived apocarotenoid in vivo is investigated and the anti-inflammatory effect of apocarotenoids with fucoxanthin partial structure such as allenic bond and epoxide residue against activated macrophages and adipocytes in vitro is evaluated. METHODS AND RESULTS LC-MS analysis indicates the presence of paracentrone, a C31 -allenic-apocarotenoid, in white adipose tissue of diabetic/obese KK-Ay and normal C57BL/6J mice fed 0.2% fucoxanthin diet for 1 week. In lipopolysaccharide-activated RAW264.7 macrophages, paracentrone as well as C26 - and C28 -allenic-apocarotenoids suppresses the overexpression of inflammatory factors. Further, apo-10'-fucoxanthinal, a fucoxanthin-derived apocarotenoid which retained epoxide residue, exhibits a most potent anti-inflammatory activity through regulating mitogen-activated protein kinases and nuclear factor-κB inflammatory signal pathways. In contrast, β-apo-8'-carotenal without allenic bond and epoxide residue lacks suppressed inflammation. In 3T3-L1 adipocytes, paracentrone, and apo-10'-fucoxanthinal downregulate the mRNA expression of proinflammatory mediators and chemokines induced by co-culture with RAW264.7 cells. CONCLUSION Dietary fucoxanthin accumulates as paracentrone as well as fucoxanthinol and amarouciaxanthin A in the mouse body. Allenic bond and epoxide residue of fucoxanthin-derived apocarotenoids have pivotal roles for anti-inflammatory action against activated macrophages and adipocytes.
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Affiliation(s)
- Naoki Takatani
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido, 041-8611, Japan
| | - Daisuke Taya
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido, 041-8611, Japan
| | - Ami Katsuki
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido, 041-8611, Japan
| | - Fumiaki Beppu
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido, 041-8611, Japan
| | - Yumiko Yamano
- Laboratory of Organic Chemistry for Life Science, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Akimori Wada
- Laboratory of Organic Chemistry for Life Science, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Kazuo Miyashita
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido, 041-8611, Japan
| | - Masashi Hosokawa
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido, 041-8611, Japan
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112
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Kircheva N, Dobrev S, Nikolova V, Angelova S, Dudev T. Zinc and Its Critical Role in Retinitis pigmentosa: Insights from DFT/SMD Calculations. Inorg Chem 2020; 59:17347-17355. [DOI: 10.1021/acs.inorgchem.0c02664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Nikoleta Kircheva
- Institute of Optical Materials and Technologies “Acad. J. Malinowski”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Stefan Dobrev
- Institute of Optical Materials and Technologies “Acad. J. Malinowski”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Valya Nikolova
- Faculty of Chemistry and Pharmacy, Sofia University “St. Kl. Ohridski”, 1164 Sofia, Bulgaria
| | - Silvia Angelova
- Institute of Optical Materials and Technologies “Acad. J. Malinowski”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Todor Dudev
- Faculty of Chemistry and Pharmacy, Sofia University “St. Kl. Ohridski”, 1164 Sofia, Bulgaria
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113
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Widjaja-Adhi MAK, Golczak M. The molecular aspects of absorption and metabolism of carotenoids and retinoids in vertebrates. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158571. [PMID: 31770587 PMCID: PMC7244374 DOI: 10.1016/j.bbalip.2019.158571] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023]
Abstract
Vitamin A is an essential nutrient necessary for numerous basic physiological functions, including reproduction and development, immune cell differentiation and communication, as well as the perception of light. To evade the dire consequences of vitamin A deficiency, vertebrates have evolved specialized metabolic pathways that enable the absorption, transport, and storage of vitamin A acquired from dietary sources as preformed retinoids or provitamin A carotenoids. This evolutionary advantage requires a complex interplay between numerous specialized retinoid-transport proteins, receptors, and enzymes. Recent advances in molecular and structural biology resulted in a rapid expansion of our understanding of these processes at the molecular level. This progress opened new avenues for the therapeutic manipulation of retinoid homeostasis. In this review, we summarize current research related to the biochemistry of carotenoid and retinoid-processing proteins with special emphasis on the structural aspects of their physiological actions. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.
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Affiliation(s)
- Made Airanthi K Widjaja-Adhi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Marcin Golczak
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America; Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America.
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114
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Hu C, Tang L, Liu M, Lam PKS, Lam JCW, Chen L. Probiotic modulation of perfluorobutanesulfonate toxicity in zebrafish: Disturbances in retinoid metabolism and visual physiology. CHEMOSPHERE 2020; 258:127409. [PMID: 32569959 DOI: 10.1016/j.chemosphere.2020.127409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 05/27/2023]
Abstract
Perfluorobutanesulfonate (PFBS), an aquatic pollutant of emerging concern, is found to disturb gut microbiota, retinoid metabolism and visual signaling in teleosts, while probiotic supplementation can shape gut microbial community to improve retinoid absorption. However, it remains unknown whether probiotic bacteria can modulate the toxicities of PFBS on retinoid metabolism and visual physiology. In the present study, adult zebrafish were exposed for 28 days to 0, 10 and 100 μg/L PFBS, with or without dietary administration of probiotic Lactobacillus rhamnosus. Interaction between PFBS and probiotic was examined regarding retinoid dynamics (intestine, liver and eye) and visual stimuli transmission. PFBS single exposures remarkably inhibited the absorption of retinyl ester in female intestines, which were, however, restored by probiotic to normal status. Although coexposure scenarios markedly increased the hepatic storage of retinyl ester in females, mobilization of retinol was reduced in livers by single or combined exposures regardless of sex. In the eyes, transport and catalytic conversion of retinol to retinal and retinoic acid were interrupted by PFBS alone, which were efficiently antagonized by probiotic presumably through an indirect action. In response to the availability of retinal chromophore, transcriptions of opsins and arrestin genes were altered adaptively to control visual perception and termination. Neurotransmission across retina circuitry was changed accordingly, centering on epinephrine and norepinephrine. In summary, the present study found the efficient modulation of probiotic on retinoid metabolic disorders of PFBS pollution, which subsequently impacted visual signaling. A future work is warranted to provide mechanistic clues in retinoid interaction.
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Affiliation(s)
- Chenyan Hu
- School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan, 430072, China
| | - Lizhu Tang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mengyuan Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Paul K S Lam
- State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong, China
| | - James C W Lam
- Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong, China.
| | - Lianguo Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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115
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Sechrest ER, Murphy J, Senapati S, Goldberg AFX, Park PSH, Kolandaivelu S. Loss of PRCD alters number and packaging density of rhodopsin in rod photoreceptor disc membranes. Sci Rep 2020; 10:17885. [PMID: 33087780 PMCID: PMC7577997 DOI: 10.1038/s41598-020-74628-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/28/2020] [Indexed: 02/06/2023] Open
Abstract
Progressive rod-cone degeneration (PRCD) is a small protein localized to photoreceptor outer segment (OS) disc membranes. Several mutations in PRCD are linked to retinitis pigmentosa (RP) in canines and humans, and while recent studies have established that PRCD is required for high fidelity disc morphogenesis, its precise role in this process remains a mystery. To better understand the part which PRCD plays in disease progression as well as its contribution to photoreceptor OS disc morphogenesis, we generated a Prcd-KO animal model using CRISPR/Cas9. Loss of PRCD from the retina results in reduced visual function accompanied by slow rod photoreceptor degeneration. We observed a significant decrease in rhodopsin levels in Prcd-KO retina prior to photoreceptor degeneration. Furthermore, ultrastructural analysis demonstrates that rod photoreceptors lacking PRCD display disoriented and dysmorphic OS disc membranes. Strikingly, atomic force microscopy reveals that many disc membranes in Prcd-KO rod photoreceptor neurons are irregular, containing fewer rhodopsin molecules and decreased rhodopsin packing density compared to wild-type discs. This study strongly suggests an important role for PRCD in regulation of rhodopsin incorporation and packaging density into disc membranes, a process which, when dysregulated, likely gives rise to the visual defects observed in patients with PRCD-associated RP.
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Affiliation(s)
- Emily R Sechrest
- Department of Pharmaceutical Sciences, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA.,Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA
| | - Joseph Murphy
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA.,Department of Biochemistry, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA
| | - Subhadip Senapati
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | | | - Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Saravanan Kolandaivelu
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA. .,Department of Biochemistry, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA.
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116
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Odoemelam CS, Percival B, Wallis H, Chang MW, Ahmad Z, Scholey D, Burton E, Williams IH, Kamerlin CL, Wilson PB. G-Protein coupled receptors: structure and function in drug discovery. RSC Adv 2020; 10:36337-36348. [PMID: 35517958 PMCID: PMC9057076 DOI: 10.1039/d0ra08003a] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
The G-protein coupled receptors (GPCRs) superfamily comprise similar proteins arranged into families or classes thus making it one of the largest in the mammalian genome. GPCRs take part in many vital physiological functions making them targets for numerous novel drugs. GPCRs share some distinctive features, such as the seven transmembrane domains, they also differ in the number of conserved residues in their transmembrane domain. Here we provide an introductory and accessible review detailing the computational advances in GPCR pharmacology and drug discovery. An overview is provided on family A-C GPCRs; their structural differences, GPCR signalling, allosteric binding and cooperativity. The dielectric constant (relative permittivity) of proteins is also discussed in the context of site-specific environmental effects.
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Affiliation(s)
| | - Benita Percival
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Helen Wallis
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Ming-Wei Chang
- Nanotechnology and Integrated Bioengineering Centre, University of Ulster Jordanstown Campus Newtownabbey BT37 0QB Northern Ireland UK
| | - Zeeshan Ahmad
- De Montfort University The Gateway Leicester LE1 9BH UK
| | - Dawn Scholey
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Emily Burton
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Ian H Williams
- Department of Chemistry, University of Bath Claverton Down Bath BA1 7AY UK
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117
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Sears AE, Albiez S, Gulati S, Wang B, Kiser P, Kovacik L, Engel A, Stahlberg H, Palczewski K. Single particle cryo-EM of the complex between interphotoreceptor retinoid-binding protein and a monoclonal antibody. FASEB J 2020; 34:13918-13934. [PMID: 32860273 PMCID: PMC7589273 DOI: 10.1096/fj.202000796rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 08/06/2020] [Accepted: 08/07/2020] [Indexed: 01/08/2023]
Abstract
Interphotoreceptor retinoid‐binding protein (IRBP) is a highly expressed protein secreted by rod and cone photoreceptors that has major roles in photoreceptor homeostasis as well as retinoid and polyunsaturated fatty acid transport between the neural retina and retinal pigment epithelium. Despite two crystal structures reported on fragments of IRBP and decades of research, the overall structure of IRBP and function within the visual cycle remain unsolved. Here, we studied the structure of native bovine IRBP in complex with a monoclonal antibody (mAb5) by cryo‐electron microscopy, revealing the tertiary and quaternary structure at sufficient resolution to clearly identify the complex components. Complementary mass spectrometry experiments revealed the structure and locations of N‐linked carbohydrate post‐translational modifications. This work provides insight into the structure of IRBP, displaying an elongated, flexible three‐dimensional architecture not seen among other retinoid‐binding proteins. This work is the first step in elucidation of the function of this enigmatic protein.
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Affiliation(s)
- Avery E Sears
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH, USA.,Department of Ophthalmology, Gavin Herbert Eye Institute, University of California-Irvine, Irvine, CA, USA
| | - Stefan Albiez
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | | | - Benlian Wang
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH, USA
| | - Philip Kiser
- Department of Physiology & Biophysics, School of Medicine, University of California-Irvine, Irvine, CA, USA.,Research Service, VA Long Beach Healthcare System, Long Beach, CA, USA
| | - Lubomir Kovacik
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | - Andreas Engel
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Basel, Switzerland
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California-Irvine, Irvine, CA, USA.,Department of Physiology & Biophysics, School of Medicine, University of California-Irvine, Irvine, CA, USA.,Department of Chemistry, University of California-Irvine, Irvine, CA, USA
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118
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Katayama K, Takeyama Y, Enomoto A, Imai H, Kandori H. Disruption of Hydrogen-Bond Network in Rhodopsin Mutations Cause Night Blindness. J Mol Biol 2020; 432:5378-5389. [PMID: 32795534 DOI: 10.1016/j.jmb.2020.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/14/2020] [Accepted: 08/04/2020] [Indexed: 01/09/2023]
Abstract
Rhodopsin is the photosensitive protein, which binds to 11-cis-retinal as its chromophore. In the dark, rhodopsin exists as a stable complex between the opsin moiety and 11-cis-retinal. The absorption of a light photon converts 11-cis-retinal to all-trans-retinal and initiates our vision. As a result, the increase in the rate of dark activation of rhodopsin reduces its photosensitivity resulting in night blindness. The mutations, G90D and T94I are night blindness-causing mutations that exhibit completely different physicochemical characteristics associated with the dark activation of rhodopsin, such as a high rate of thermal isomerization of 11-cis-retinal and a slow pigment regeneration. To elucidate the molecular mechanism by which G90D and T94I mutations affect rhodopsin dark activation and regeneration, we performed light-induced difference FTIR spectroscopy on dark and primary photo-intermediate states of G90D and T94I mutants. The FTIR spectra clearly show that both charged G90D and hydrophobic T94I mutants alter the H-bond network at the Schiff base region of the chromophore, which weakens the electrostatic interaction with Glu113 counterion. Our results further show an altered water-mediated H-bond network around the central transmembrane region of mutant rhodopsin, which is reminiscent of the active Meta-II state. This altered water-mediated H-bond network may cause thermal isomerization of the chromophore and facilitate rhodopsin dark activation.
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Affiliation(s)
- Kota Katayama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan; PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
| | - Yuri Takeyama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Akiko Enomoto
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Hiroo Imai
- Primate Research Institute, Kyoto University, Inuyama 484-8506, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
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119
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Abstract
The visual phototransduction cascade begins with a cis-trans photoisomerization of a retinylidene chromophore associated with the visual pigments of rod and cone photoreceptors. Visual opsins release their all-trans-retinal chromophore following photoactivation, which necessitates the existence of pathways that produce 11-cis-retinal for continued formation of visual pigments and sustained vision. Proteins in the retinal pigment epithelium (RPE), a cell layer adjacent to the photoreceptor outer segments, form the well-established "dark" regeneration pathway known as the classical visual cycle. This pathway is sufficient to maintain continuous rod function and support cone photoreceptors as well although its throughput has to be augmented by additional mechanism(s) to maintain pigment levels in the face of high rates of photon capture. Recent studies indicate that the classical visual cycle works together with light-dependent processes in both the RPE and neural retina to ensure adequate 11-cis-retinal production under natural illuminances that can span ten orders of magnitude. Further elucidation of the interplay between these complementary systems is fundamental to understanding how cone-mediated vision is sustained in vivo. Here, we describe recent advances in understanding how 11-cis-retinal is synthesized via light-dependent mechanisms.
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120
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Rivas A, Pequerul R, Barracco V, Domínguez M, López S, Jiménez R, Parés X, Alvarez R, Farrés J, de Lera AR. Synthesis of C11-to-C14 methyl-shifted all-trans-retinal analogues and their activities on human aldo-keto reductases. Org Biomol Chem 2020; 18:4788-4801. [PMID: 32530010 DOI: 10.1039/d0ob01084g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Human aldo-keto reductases (AKRs) are enzymes involved in the reduction, among other substrates, of all-trans-retinal to all-trans-retinol (vitamin A), thus contributing to the control of the levels of retinoids in organisms. Structure-activity relationship studies of a series of C11-to-C14 methyl-shifted (relative to natural C13-methyl) all-trans-retinal analogues as putative substrates of AKRs have been reported. The synthesis of these retinoids was based on the formation of a C10-C11 single bond of the pentaene skeleton starting from a trienyl iodide and the corresponding dienylstannanes and dienylsilanes, using the Stille-Kosugi-Migita and Hiyama-Denmark cross-coupling reactions, respectively. Since these reagents differ by the location and presence of methyl groups at the dienylorganometallic fragment, the study also provided insights into the ability of the different positional isomers to undergo cross-coupling and the sensitivity of these processes to steric hindrance. The resulting C11-to-C14 methyl-shifted all-trans-retinal analogues were found to be active substrates when tested with AKR1B1 and AKR1B10 enzymes, although relevant differences in substrate specificities were noted. For AKR1B1, all analogues exhibited higher catalytic efficiency (kcat/Km) than parent all-trans-retinal. In addition, only all-trans-11-methylretinal, the most hydrophobic derivative, showed a higher value of kcat/Km = 106 000 ± 23 200 mM-1 min-1 for AKR1B10, which is in fact the highest value from all known retinoid substrates of this enzyme. The novel structures, identified as efficient AKR substrates, may serve in the design of selective inhibitors with potential pharmacological interest.
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Affiliation(s)
- Aurea Rivas
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, E-36310 Vigo, Spain.
| | - Raquel Pequerul
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain
| | - Vito Barracco
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain and Department of Biology, Biochemistry Unit, University of Pisa, I-56126 Pisa, Italy
| | - Marta Domínguez
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, E-36310 Vigo, Spain.
| | - Susana López
- Departamento de Química Orgánica, Facultade de Química, Universidade de Santiago de Compostela, E-15782 Santiago, Spain
| | - Rafael Jiménez
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain
| | - Xavier Parés
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain
| | - Rosana Alvarez
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, E-36310 Vigo, Spain.
| | - Jaume Farrés
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain
| | - Angel R de Lera
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, E-36310 Vigo, Spain.
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121
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Orlans HO, Barnard AR, Patrício MI, McClements ME, MacLaren RE. Effect of AAV-Mediated Rhodopsin Gene Augmentation on Retinal Degeneration Caused by the Dominant P23H Rhodopsin Mutation in a Knock-In Murine Model. Hum Gene Ther 2020; 31:730-742. [DOI: 10.1089/hum.2020.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Harry O. Orlans
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Alun R. Barnard
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, United Kingdom
| | - Maria I. Patrício
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, United Kingdom
| | | | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
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122
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Sugiura M, Tsunoda SP, Hibi M, Kandori H. Molecular Properties of New Enzyme Rhodopsins with Phosphodiesterase Activity. ACS OMEGA 2020; 5:10602-10609. [PMID: 32426619 PMCID: PMC7227045 DOI: 10.1021/acsomega.0c01113] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 04/02/2020] [Indexed: 05/08/2023]
Abstract
The choanoflagellate Salpingoeca rosetta contains a chimeric rhodopsin protein composed of an N-terminal rhodopsin (Rh) domain and a C-terminal cyclic nucleotide phosphodiesterase (PDE) domain. The Rh-PDE enzyme (SrRh-PDE), which decreases the concentrations of cyclic nucleotides such as cGMP and cAMP in light, is a useful tool in optogenetics. Recently, eight additional Rh-PDE enzymes were found in choanoflagellate species, four from Choanoeca flexa and the other four from other species. In this paper, we studied the molecular properties of these new Rh-PDEs, which were compared with SrRh-PDE. Upon expression in HEK293 cells, four Rh-PDE proteins, including CfRh-PDE2 and CfRh-PDE3, exhibited no PDE activity when assessed by in-cell measurements and in vitro HPLC analysis. On the other hand, CfRh-PDE1 showed light-dependent PDE activity toward cGMP, which absorbed maximally at 491 nm. Therefore, CfRh-PDE1 is presumably responsible for colony inversion in C. flexa by absorbing blue-green light. The molecular properties of MrRh-PDE were similar to those of SrRh-PDE, although the λmax of MrRh-PDE (516 nm) was considerably red-shifted from that of SrRh-PDE (492 nm). One Rh-PDE, AsRh-PDE, did not contain the retinal-binding Lys at TM7 and showed cAMP-specific PDE activity both in the dark and light. These results provide mechanistic insight into rhodopsin-mediated, light-dependent regulation of second-messenger levels in eukaryotic microbes.
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Affiliation(s)
- Masahiro Sugiura
- Department
of Life Science and Applied Chemistry, Nagoya
Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Satoshi P. Tsunoda
- Department
of Life Science and Applied Chemistry, Nagoya
Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology
Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- PRESTO, Japan
Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Masahiko Hibi
- Division
of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Hideki Kandori
- Department
of Life Science and Applied Chemistry, Nagoya
Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology
Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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123
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Yokoyama S, Jia H. Origin and adaptation of green-sensitive (RH2) pigments in vertebrates. FEBS Open Bio 2020; 10:873-882. [PMID: 32189477 PMCID: PMC7193153 DOI: 10.1002/2211-5463.12843] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 02/20/2020] [Accepted: 03/16/2020] [Indexed: 12/12/2022] Open
Abstract
One of the critical times for the survival of animals is twilight where the most abundant visible lights are between 400 and 550 nanometres (nm). Green-sensitive RH2 pigments help nonmammalian vertebrate species to better discriminate wavelengths in this blue-green region. Here, evaluation of the wavelengths of maximal absorption (λmax s) of genetically engineered RH2 pigments representing 13 critical stages of vertebrate evolution revealed that the RH2 pigment of the most recent common ancestor of vertebrates had a λmax of 503 nm, while the 12 ancestral pigments exhibited an expanded range in λmax s between 474 and 524 nm, and present-day RH2 pigments have further expanded the range to ~ 450-530 nm. During vertebrate evolution, eight out of the 16 significant λmax shifts (or |Δλmax | ≥ 10 nm) of RH2 pigments identified were fully explained by the repeated mutations E122Q (twice), Q122E (thrice) and M207L (twice), and A292S (once). Our data indicated that the highly variable λmax s of teleost RH2 pigments arose from gene duplications followed by accelerated amino acid substitution.
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Affiliation(s)
- Shozo Yokoyama
- Department of BiologyEmory UniversityAtlantaGAUSA
- Willamette ViewPortlandORUSA
| | - Huiyong Jia
- Department of BiologyEmory UniversityAtlantaGAUSA
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124
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von Lintig J, Moon J, Babino D. Molecular components affecting ocular carotenoid and retinoid homeostasis. Prog Retin Eye Res 2020; 80:100864. [PMID: 32339666 DOI: 10.1016/j.preteyeres.2020.100864] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/13/2020] [Accepted: 04/17/2020] [Indexed: 12/15/2022]
Abstract
The photochemistry of vision employs opsins and geometric isomerization of their covalently bound retinylidine chromophores. In different animal classes, these light receptors associate with distinct G proteins that either hyperpolarize or depolarize photoreceptor membranes. Vertebrates also use the acidic form of chromophore, retinoic acid, as the ligand of nuclear hormone receptors that orchestrate eye development. To establish and sustain these processes, animals must acquire carotenoids from the diet, transport them, and metabolize them to chromophore and retinoic acid. The understanding of carotenoid metabolism, however, lagged behind our knowledge about the biology of their receptor molecules. In the past decades, much progress has been made in identifying the genes encoding proteins that mediate the transport and enzymatic transformations of carotenoids and their retinoid metabolites. Comparative analysis in different animal classes revealed how evolutionary tinkering with a limited number of genes evolved different biochemical strategies to supply photoreceptors with chromophore. Mutations in these genes impair carotenoid metabolism and induce various ocular pathologies. This review summarizes this advancement and introduces the involved proteins, including the homeostatic regulation of their activities.
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Affiliation(s)
- Johannes von Lintig
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
| | - Jean Moon
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Darwin Babino
- Department of Ophthalmology, School of Medicine, University of Washington, Seattle, WA, USA
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125
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Karn A, Zhao C, Yang F, Cui J, Gao Z, Wang M, Wang F, Xiao H, Zheng J. In-vivo biotransformation of citrus functional components and their effects on health. Crit Rev Food Sci Nutr 2020; 61:756-776. [PMID: 32255367 DOI: 10.1080/10408398.2020.1746234] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Citrus, one of the most popular fruits worldwide, contains various functional components, including flavonoids, dietary fibers (DFs), essential oils (EOs), synephrines, limonoids, and carotenoids. The functional components of citrus attract special attention due to their health-promoting effects. Food components undergo complex biotransformation by host itself and the gut microbiota after oral intake, which alters their bioaccessibility, bioavailability, and bioactivity in the host body. To better understand the health effects of citrus fruits, it is important to understand the in-vivo biotransformation of citrus functional components. We reviewed the biotransformation of citrus functional components (flavonoids, DFs, EOs, synephrines, limonoids, and carotenoids) in the body from their intake to excretion. In addition, we described the importance of biotransformation in terms of health effects. This review would facilitate mechanistic understanding of the health-promoting effect of citrus and its functional components, and also provide guidance for the development of health-promoting foods based on citrus and its functional components.
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Affiliation(s)
- Abhisek Karn
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chengying Zhao
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Feilong Yang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiefen Cui
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zili Gao
- Department of Food Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Minqi Wang
- Department of Food Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Fengzhong Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hang Xiao
- Department of Food Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Jinkai Zheng
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
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126
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Li W. Residue-Residue Mutual Work Analysis of Retinal-Opsin Interaction in Rhodopsin: Implications for Protein-Ligand Binding. J Chem Theory Comput 2020; 16:1834-1842. [PMID: 31972074 DOI: 10.1021/acs.jctc.9b01035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Energetic contributions at the single-residue level for retinal-opsin interactions in rhodopsin were studied by combining molecular dynamics simulations, transition path sampling, and a newly developed energy decomposition approach. The virtual work at an infinitesimal time interval was decomposed into the work components on one residue due to its interaction with another residue, which were then averaged over the transition path ensemble along a proposed reaction coordinate. Such residue-residue mutual work analysis on 62 residues within the active center of rhodopsin resulted in a very sparse interaction matrix, which is generally not symmetric but antisymmetric to some extent. Fourteen residues were identified to be major players in retinal relaxation along a plausible pathway from bathorhodopsin to the blue-shifted intermediate, which is in good agreement with an existing NMR study. Based on the matrix of mutual work, a comprehensive network was constructed to provide detailed insights into the chromophore-protein interaction from a viewpoint of energy flow.
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Affiliation(s)
- Wenjin Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
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127
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Kaneshige Y, Hayashi F, Morigaki K, Tanimoto Y, Yamashita H, Fujii M, Awazu A. Affinity of rhodopsin to raft enables the aligned oligomer formation from dimers: Coarse-grained molecular dynamics simulation of disk membranes. PLoS One 2020; 15:e0226123. [PMID: 32032370 PMCID: PMC7006936 DOI: 10.1371/journal.pone.0226123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/13/2020] [Indexed: 12/16/2022] Open
Abstract
The visual photopigment protein rhodopsin (Rh) is a typical G protein-coupled receptor (GPCR) that initiates the phototransduction cascade in retinal disk membrane of rod-photoreceptor cells. Rh molecule has a tendency to form dimer, and the dimer tends to form rows, which is suggested to heighten phototransduction efficiency in single-photon regime. In addition, the dimerization confers Rh an affinity for lipid raft, i.e. raftophilicity. However, the mechanism by which Rh-dimer raftophilicity contributes to the organization of the higher order structure remains unknown. In this study, we performed coarse-grained molecular dynamics simulations of a disk membrane model containing unsaturated lipids, saturated lipids with cholesterol, and Rh-dimers. We described the Rh-dimers by two-dimensional particle populations where the palmitoyl moieties of each Rh exhibits raftophilicity. We simulated the structuring of Rh in a disk for two types of Rh-dimer, i.e., the most and second most stable Rh dimers, which exposes the raftophilic regions at the dimerization-interface (H1/H8 dimer) and two edges away from the interface (H4/H5 dimer), respectively. Our simulations revealed that only the H1/H8 dimer could form a row structure. A small number of raftophilic lipids recruited to and intercalated in a narrow space between H1/H8 dimers stabilize the side-by-side interaction between dimers in a row. Our results implicate that the nano-sized lipid raft domains act as a “glue” to organize the long row structures of Rh-dimers.
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Affiliation(s)
- Yukito Kaneshige
- Department of Mathematical and Life Sciences, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan
| | - Fumio Hayashi
- Graduate School of Science, Kobe University, Rokkodaicho, Nada, Kobe, Japan
| | - Kenichi Morigaki
- Biosignal Research Center, Kobe University, Rokkodaicho, Nada, Kobe, Japan
| | - Yasushi Tanimoto
- Graduate School of Science, Kobe University, Rokkodaicho, Nada, Kobe, Japan
| | - Hayato Yamashita
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Masashi Fujii
- Department of Mathematical and Life Sciences, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan
| | - Akinori Awazu
- Department of Mathematical and Life Sciences, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan
- * E-mail:
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128
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Park DW, Jeon H, So R, Kang SC. Centella asiatica extract prevents visual impairment by promoting the production of rhodopsin in the retina. Nutr Res Pract 2020; 14:203-217. [PMID: 32528628 PMCID: PMC7263902 DOI: 10.4162/nrp.2020.14.3.203] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 10/29/2019] [Accepted: 11/26/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND/OBJECTIVE Centella asiatica, also known as Gotu kola, is a tropical medicinal plant native to Madagascar, Southeast Asia, and South Africa. It is well known to have biological activities, including wound healing, anti-inflammatory, antidiabetic, cytotoxic, and antioxidant effects. The purpose of this study was to determine the efficacy of extracts of C. asiatica against age-related eye degeneration and to examine their physiological activities. MATERIALS/METHODS To determine the effects of CA-HE50 (C. asiatica 50% EtOH extract) on retinal pigment cells, we assessed the cytotoxicity of CoCl2 and oxidized-A2E in ARPE-19 cells and observed the protective effects of CA-HE50 against N-methyl-N-nitrosourea (MNU)-induced retinal damage in C57BL/6 mice. In particular, we measured factors related to apoptosis and anti-oxidation and the protein levels of rhodopsin/opsin. We also measured glucose uptake to characterize glucose metabolism, a major factor in cell protection. RESULTS Induction of cytotoxicity with CoCl2 and oxidized-A2E inhibited decreases in the viability of ARPE-19 cells when CA-HE50 was administered, and promoted glucose uptake under normal conditions (P < 0.05). In addition, CA-HE50 inhibited degeneration/apoptosis of the retina in the context of MNU-induced toxicity (P < 0.05). In particular, CA-HE50 at 200 mg/kg inhibited the cleavage of pro-caspase-3 and pro-poly (ADP-ribose)-polymerase and maintained the expressions of nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 similar to normal control levels. Rhodopsin/opsin expression was maintained at a higher level than in normal controls. CONCLUSION A series of experiments confirmed that CA-HE50 was effective for inhibiting or preventing age-related eye damage/degeneration. Based on these results, we believe it is worthwhile to develop drugs or functional foods related to age-related eye degeneration using CA-HE50.
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Affiliation(s)
- Dae Won Park
- Department of Oriental Medicine Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Korea
| | - Hyelin Jeon
- Research Institute, Genencell Co. Ltd., Yongin 16950, Korea.,BioMedical Research Institute, Kyung Hee University, Yongin 17104, Korea
| | - Rina So
- Department of Oriental Medicine Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Korea
| | - Se Chan Kang
- Department of Oriental Medicine Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Korea.,BioMedical Research Institute, Kyung Hee University, Yongin 17104, Korea
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129
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Roy D, Levi K, Kiss V, Nevo R, Eisenbach M. Rhodopsin and melanopsin coexist in mammalian sperm cells and activate different signaling pathways for thermotaxis. Sci Rep 2020; 10:112. [PMID: 31924821 PMCID: PMC6954197 DOI: 10.1038/s41598-019-56846-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/17/2019] [Indexed: 12/19/2022] Open
Abstract
Recently, various opsin types, known to be involved in vision, were demonstrated to be present in human and mouse sperm cells and to be involved there in thermosensing for thermotaxis. In vision, each opsin type is restricted to specific cells. The situation in this respect in sperm cells is not known. It is also not known whether or not both signaling pathways, found to function in sperm thermotaxis, are each activated by specific opsins, as in vision. Here we addressed these questions. Choosing rhodopsin and melanopsin as test cases and employing immunocytochemical analysis with antibodies against these opsins, we found that the majority of sperm cells were stained by both antibodies, indicating that most of the cells contained both opsins. By employing mutant mouse sperm cells that do not express melanopsin combined with specific signaling inhibitors, we furthermore demonstrated that rhodopsin and melanopsin each activates a different pathway. Thus, in mammalian sperm thermotaxis, as in vision, rhodopsin and melanopsin each triggers a different signaling pathway but, unlike in vision, both opsin types coexist in the same sperm cells.
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Affiliation(s)
- Debarun Roy
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Kohava Levi
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Vladimir Kiss
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Reinat Nevo
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Michael Eisenbach
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel.
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130
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Buhrke D, Hildebrandt P. Probing Structure and Reaction Dynamics of Proteins Using Time-Resolved Resonance Raman Spectroscopy. Chem Rev 2019; 120:3577-3630. [PMID: 31814387 DOI: 10.1021/acs.chemrev.9b00429] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The mechanistic understanding of protein functions requires insight into the structural and reaction dynamics. To elucidate these processes, a variety of experimental approaches are employed. Among them, time-resolved (TR) resonance Raman (RR) is a particularly versatile tool to probe processes of proteins harboring cofactors with electronic transitions in the visible range, such as retinal or heme proteins. TR RR spectroscopy offers the advantage of simultaneously providing molecular structure and kinetic information. The various TR RR spectroscopic methods can cover a wide dynamic range down to the femtosecond time regime and have been employed in monitoring photoinduced reaction cascades, ligand binding and dissociation, electron transfer, enzymatic reactions, and protein un- and refolding. In this account, we review the achievements of TR RR spectroscopy of nearly 50 years of research in this field, which also illustrates how the role of TR RR spectroscopy in molecular life science has changed from the beginning until now. We outline the various methodological approaches and developments and point out current limitations and potential perspectives.
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Affiliation(s)
- David Buhrke
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17, Juni 135, D-10623 Berlin, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17, Juni 135, D-10623 Berlin, Germany
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131
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Shi WJ, Jiang YX, Ma DD, Huang GY, Xie L, Chen HX, Huang MZ, Ying GG. Dydrogesterone affects the transcription of genes in visual cycle and circadian rhythm network in the eye of zebrafish. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 183:109556. [PMID: 31509926 DOI: 10.1016/j.ecoenv.2019.109556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/05/2019] [Accepted: 08/07/2019] [Indexed: 06/10/2023]
Abstract
Dydrogesterone (DDG) is a synthetic progestin used in contraception and hormone replacement therapy. Our previous transcriptome data showed that the response to light stimulus, photoperiodism and rhythm related gene ontology (GO) terms were significantly enriched in the brain of zebrafish after chronic exposure to DDG. Here we investigated the effects of DDG on the eye of zebrafish. Zebrafish were exposed to DDG at three concentration levels (3.39, 33.1, and 329 ng L-1) for 120 days. Based on our previous transcriptome data, the transcription of genes involved in visual cycle and circadian rhythm network was examined by qPCR analysis. In the visual cycle network, exposure to all concentrations of DDG significantly decreased transcription of grk7a, aar3a and guca1d, while increased the transcription of opn1mw4 and opn1sw2 at the low concentration. Importantly, exposure to all concentrations of DDG down-regulated the transcription of rep65a that encodes a critical enzyme to catalyze the conversion from all-trans-retinal to 11-cis-retinal in the eye of male zebrafish. In the circadian rhythm network, DDG enhanced the transcription of clocka, arntl2 and nifil3-5 at all three concentrations, while it decreased the transcription of cry5, per1b, nr1d2b and si:ch211.132b12.7. In addition, DDG decreased the transcription of tefa in both males and females. Moreover, histological analysis showed the exposure to 329 ng L-1 of DDG decreased the thickness of retinal ganglion cell in the eye of male zebrafish. These results indicated that DDG exposure could affect the transcription of genes in visual cycle and circadian rhythm network in the eyes of zebrafish. This suggests that DDG has potential negative impact on the normal eye function.
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Affiliation(s)
- Wen-Jun Shi
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China
| | - Yu-Xia Jiang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Dong-Dong Ma
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China
| | - Guo-Yong Huang
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China
| | - Lingtian Xie
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China
| | - Hong-Xing Chen
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China
| | - Ming-Zhi Huang
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China
| | - Guang-Guo Ying
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China.
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132
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Rivas A, Pérez-Revenga V, Alvarez R, de Lera AR. Bidirectional Hiyama-Denmark Cross-Coupling Reactions of Bissilyldeca-1,3,5,7,9-pentaenes for the Synthesis of Symmetrical and Non-Symmetrical Carotenoids. Chemistry 2019; 25:14399-14407. [PMID: 31456273 DOI: 10.1002/chem.201903080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/20/2019] [Indexed: 02/02/2023]
Abstract
The construction of the carotenoid skeleton by Pd-catalyzed Csp2 -Csp2 cross-coupling reactions of symmetrical and non-symmetrical 1,10-bissilyldeca-1,3,5,7,9-pentaenes and the corresponding complementary alkenyl iodides has been developed. Reaction conditions for these bidirectional and orthogonal Hiyama-Denmark cross-coupling reactions of bisfunctionalized pentaenes are mild and the carotenoid products preserve the stereochemical information of the corresponding oligoene partners. The carotenoids synthesized in this manner include β,β-carotene and (3R,3'R)-zeaxanthin (symmetrical) as well as 9-cis-β,β-carotene, 7,8-dihydro-β,β-carotene and β-cryptoxanthin (non-symmetrical).
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Affiliation(s)
- Aurea Rivas
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, 36310, Vigo, Spain
| | - Víctor Pérez-Revenga
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, 36310, Vigo, Spain
| | - Rosana Alvarez
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, 36310, Vigo, Spain
| | - Angel R de Lera
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, 36310, Vigo, Spain
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133
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Zhang J, Choi EH, Tworak A, Salom D, Leinonen H, Sander CL, Hoang TV, Handa JT, Blackshaw S, Palczewska G, Kiser PD, Palczewski K. Photic generation of 11- cis-retinal in bovine retinal pigment epithelium. J Biol Chem 2019; 294:19137-19154. [PMID: 31694912 DOI: 10.1074/jbc.ra119.011169] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 10/25/2019] [Indexed: 12/19/2022] Open
Abstract
Photoisomerization of the 11-cis-retinal chromophore of rod and cone visual pigments to an all-trans-configuration is the initiating event for vision in vertebrates. The regeneration of 11-cis-retinal, necessary for sustained visual function, is an endergonic process normally conducted by specialized enzyme systems. However, 11-cis-retinal also can be formed through reverse photoisomerization from all-trans-retinal. A nonvisual opsin known as retinal pigment epithelium (RPE)-retinal G-protein-coupled receptor (RGR) was previously shown to mediate visual chromophore regeneration in photic conditions, but conflicting results have cast doubt on its role as a photoisomerase. Here, we describe high-level production of 11-cis-retinal from RPE membranes stimulated by illumination at a narrow band of wavelengths. This activity was associated with RGR and enhanced by cellular retinaldehyde-binding protein (CRALBP), which binds the 11-cis-retinal produced by RGR and prevents its re-isomerization to all-trans-retinal. The activity was recapitulated with cells heterologously expressing RGR and with purified recombinant RGR. Using an RGR variant, K255A, we confirmed that a Schiff base linkage at Lys-255 is critical for substrate binding and isomerization. Single-cell RNA-Seq analysis of the retina and RPE tissue confirmed that RGR is expressed in human and bovine RPE and Müller glia, whereas mouse RGR is expressed in RPE but not in Müller glia. These results provide key insights into the mechanisms of physiological retinoid photoisomerization and suggest a novel mechanism by which RGR, in concert with CRALBP, regenerates the visual chromophore in the RPE under sustained light conditions.
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Affiliation(s)
- Jianye Zhang
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
| | - Elliot H Choi
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Aleksander Tworak
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
| | - David Salom
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
| | - Henri Leinonen
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
| | - Christopher L Sander
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Thanh V Hoang
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - James T Handa
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.,Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
| | | | - Philip D Kiser
- Department of Physiology and Biophysics, University of California, Irvine, California 92697.,Research Service, Veterans Affairs Long Beach Healthcare System, Long Beach, California 90822
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
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134
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Azizzadeh Pormehr L, Ahmadian S, Daftarian N, Mousavi SA, Shafiezadeh M. PRPF31 reduction causes mis-splicing of the phototransduction genes in human organotypic retinal culture. Eur J Hum Genet 2019; 28:491-498. [PMID: 31654038 DOI: 10.1038/s41431-019-0531-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 09/30/2019] [Accepted: 10/13/2019] [Indexed: 12/22/2022] Open
Abstract
PRPF31 is ubiquitously expressed splicing factor and has an essential role in the pre-mRNA splicing in all tissues. However, it is not clear how reduced expression of this general splicing factor leads to retinal restricted disease, retinitis pigmentosa (RP). In this study, we used RNA interference and RNA-sequencing to mimic the PRPF31 haploinsufficiency in human organotypic retinal cultures (HORCs). We examined the effects of PRPF31 deficiency on splicing by analyzing the differential exon usages (DEUs) and intron retentions of the retinal transcriptome. Our results revealed that the PRPF31 deficiency causes mis-splicing of genes involved in RNA processing (PRPF3, PRPF8, PRPF4, and PRPF19) and phototransduction (RHO, ROM1, FSCN2, GNAT2, and GNAT1) in the retina in the PRPF31 reduced samples. Mis-splicing of genes implicated in phototransduction was associated with photoreceptor degeneration observed in RP patients. Our data revealed that PRPF31 deficiency leads to the mis-splicing of a distinct subset of pre-mRNAs with a widespread effect on phototransduction and RNA processing.
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Affiliation(s)
- Leila Azizzadeh Pormehr
- Department of Biochemistry, Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Shahin Ahmadian
- Department of Biochemistry, Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran.
| | - Narsis Daftarian
- Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. .,Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Seyed Ahmad Mousavi
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Mahshid Shafiezadeh
- Department of Biochemistry, Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
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135
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Jang JC, Noh GE, Kim YR, Yu YM, Kim JM. Spectral sensitivity and photoresponse in the rock bream Oplegnathus fasciatus and their relationships with the absorption maximum of the photoreceptor. FISH PHYSIOLOGY AND BIOCHEMISTRY 2019; 45:1759-1769. [PMID: 31243686 DOI: 10.1007/s10695-019-00672-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 06/05/2019] [Indexed: 06/09/2023]
Abstract
The spectral characteristics of visual pigments are a major determinant in eliciting a response to light. To study the absorption maximum of the photoreceptors and their sensitivity to light in fish, rod outer segments (ROS) and cone cells were purified from the rock bream Oplegnathus fasciatus adapted to the dark. Ultraviolet/visible spectroscopic analyses of the ROS in the dark and its difference spectra indicated an absorption maximum of the visual pigment at ~ 500 nm, and each eye of 1-year-old rock bream contained at least 1.2 nmol of rhodopsin-like visual pigments. Microspectrophotometric analysis of the cone cell outer segments led to identification of three visual pigments with individual absorption maxima at 425, 520, and 585 nm. Monochromatic light-emitting diode (LED) modules with different wavelengths (violet 405 nm, blue 465 nm, cyan 505 nm, green 530 nm, amber 590 nm, and red 655 nm) were constructed to examine the spectral sensitivity and photoresponse in association with the absorption maximum of the photoreceptor. Analysis of chromophore decay upon illumination with each LED at low (27 μmol/m2/s) and high (343 μmol/m2/s) intensities showed the highest sensitivity of the photoreceptor upon illumination with the 505-nm cyan LED, followed by LEDs with wavelengths of 530 nm > 465 nm > 405 nm > 590 nm > 655 nm. Photoresponse analysis of the fish using a video tracking system, in the dark and upon illumination, also showed faster movement of fish with illumination with the cyan LED followed by in the order of green ≈ blue > violet > amber > red. These results indicated that a light with a wavelength closer to the absorption maximum of rhodopsin was more effective in eliciting a response to the light.
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Affiliation(s)
- Jun-Chul Jang
- Department of Fisheries Biology, Pukyong National University, Busan, 48513, South Korea
- East Sea Branch, Korea Fisheries Resources Agency, Pohang, 37688, South Korea
| | - Gyeong Eon Noh
- Genetic & Breeding Research Center, National Institute of Fisheries Science, Geoje, 53334, South Korea
| | - Yeo-Reum Kim
- Department of Fisheries Biology, Pukyong National University, Busan, 48513, South Korea
| | - Young-Moon Yu
- LED-Marine Convergence Technology R&BD Center, Pukyong National University, Busan, 48547, South Korea
| | - Jong-Myoung Kim
- Department of Fisheries Biology, Pukyong National University, Busan, 48513, South Korea.
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136
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Zhao DY, Pöge M, Morizumi T, Gulati S, Van Eps N, Zhang J, Miszta P, Filipek S, Mahamid J, Plitzko JM, Baumeister W, Ernst OP, Palczewski K. Cryo-EM structure of the native rhodopsin dimer in nanodiscs. J Biol Chem 2019; 294:14215-14230. [PMID: 31399513 PMCID: PMC6768649 DOI: 10.1074/jbc.ra119.010089] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 08/02/2019] [Indexed: 02/03/2023] Open
Abstract
Imaging of rod photoreceptor outer-segment disc membranes by atomic force microscopy and cryo-electron tomography has revealed that the visual pigment rhodopsin, a prototypical class A G protein-coupled receptor (GPCR), can organize as rows of dimers. GPCR dimerization and oligomerization offer possibilities for allosteric regulation of GPCR activity, but the detailed structures and mechanism remain elusive. In this investigation, we made use of the high rhodopsin density in the native disc membranes and of a bifunctional cross-linker that preserves the native rhodopsin arrangement by covalently tethering rhodopsins via Lys residue side chains. We purified cross-linked rhodopsin dimers and reconstituted them into nanodiscs for cryo-EM analysis. We present cryo-EM structures of the cross-linked rhodopsin dimer as well as a rhodopsin dimer reconstituted into nanodiscs from purified monomers. We demonstrate the presence of a preferential 2-fold symmetrical dimerization interface mediated by transmembrane helix 1 and the cytoplasmic helix 8 of rhodopsin. We confirmed this dimer interface by double electron-electron resonance measurements of spin-labeled rhodopsin. We propose that this interface and the arrangement of two protomers is a prerequisite for the formation of the observed rows of dimers. We anticipate that the approach outlined here could be extended to other GPCRs or membrane receptors to better understand specific receptor dimerization mechanisms.
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Affiliation(s)
- Dorothy Yanling Zhao
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Matthias Pöge
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Takefumi Morizumi
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Sahil Gulati
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California, Irvine, California 92697
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Ned Van Eps
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Jianye Zhang
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California, Irvine, California 92697
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Przemyslaw Miszta
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw 02-093, Poland
| | - Slawomir Filipek
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw 02-093, Poland
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Oliver P Ernst
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California, Irvine, California 92697
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
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137
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Leinonen H, Choi EH, Gardella A, Kefalov VJ, Palczewski K. A Mixture of U.S. Food and Drug Administration-Approved Monoaminergic Drugs Protects the Retina From Light Damage in Diverse Models of Night Blindness. Invest Ophthalmol Vis Sci 2019; 60:1442-1453. [PMID: 30947334 PMCID: PMC6736410 DOI: 10.1167/iovs.19-26560] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Purpose The purpose of this study was to test the extent of light damage in different models of night blindness and apply these paradigms in testing the therapeutic efficacy of combination therapy by drugs acting on the Gi, Gs, and Gq protein-coupled receptors. Methods Acute bright light exposure was used to test susceptibility to light damage in mice lacking the following crucial phototransduction proteins: rod transducin (GNAT1), cone transducin (GNAT2), visual arrestin 1 (ARR1), and rhodopsin kinase 1 (GRK1). Mice were intraperitoneally injected with either vehicle or drug combination consisting of metoprolol (β1-receptor antagonist), bromocriptine (dopamine family-2 receptor agonist) and tamsulosin (α1-receptor antagonist) before bright light exposure. Light damage was primarily assessed with optical coherence tomography and inspection of cone population in retinal whole mounts. Retinal inflammation was assessed in a subset of experiments using autofluorescence imaging by scanning laser ophthalmoscopy and by postmortem inspection of microglia and astrocyte activity. Results The Gnat1−/− mice showed slightly increased susceptibility to rod light damage, whereas the Gnat2−/− mice were very resistant. The Arr1−/− and Grk1−/− mice were sensitive for both rod and cone light damage and showed robust retinal inflammation 7 days after bright light exposure. Pretreatment with metoprolol + bromocriptine + tamsulosin rescued the retina in all genetic backgrounds, starting at doses of 0.2 mg/kg metoprolol, 0.02 mg/kg bromocriptine, and 0.01 mg/kg tamsulosin in the Gnat1−/− mice. The therapeutic drug doses increased in parallel with light-damage severity. Conclusions Our results suggest that congenital stationary night blindness and Oguchi disease patients can be at an elevated risk of the toxic effects of bright light. Furthermore, systems pharmacology drug regimens that stimulate Gi signaling and attenuate Gs and Gq signaling present a promising disease-modifying therapy for photoreceptor degenerative diseases.
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Affiliation(s)
- Henri Leinonen
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California-Irvine, Irvine, California, United States.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Elliot H Choi
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California-Irvine, Irvine, California, United States.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Anthony Gardella
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, United States
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University, St. Louis, Missouri, United States
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California-Irvine, Irvine, California, United States.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
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138
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Single Proteoliposome High-Content Analysis Reveals Differences in the Homo-Oligomerization of GPCRs. Biophys J 2019; 115:300-312. [PMID: 30021106 DOI: 10.1016/j.bpj.2018.05.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/28/2018] [Accepted: 05/31/2018] [Indexed: 11/23/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) control vital cellular signaling pathways. GPCR oligomerization is proposed to increase signaling diversity. However, many reports have arrived at disparate conclusions regarding the existence, stability, and stoichiometry of GPCR oligomers, partly because of cellular complexity and ensemble averaging of intrareconstitution heterogeneities that complicate the interpretation of oligomerization data. To overcome these limitations, we exploited fluorescence-microscopy-based high-content analysis of single proteoliposomes. This allowed multidimensional quantification of intrinsic monomer-monomer interactions of three class A GPCRs (β2-adrenergic receptor, cannabinoid receptor type 1, and opsin). Using a billion-fold less protein than conventional assays, we quantified oligomer stoichiometries, association constants, and the influence of two ligands and membrane curvature on oligomerization, revealing key similarities and differences for three GPCRs with decidedly different physiological functions. The assays introduced here will assist with the quantitative experimental observation of oligomerization for transmembrane proteins in general.
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139
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Lamprecht R. Regulation of signaling proteins in the brain by light. Prog Neurobiol 2019; 180:101638. [DOI: 10.1016/j.pneurobio.2019.101638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/29/2019] [Accepted: 06/06/2019] [Indexed: 12/20/2022]
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140
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Sancho-Pelluz J, Cui X, Lee W, Tsai YT, Wu WH, Justus S, Washington I, Hsu CW, Park KS, Koch S, Velez G, Bassuk AG, Mahajan VB, Lin CS, Tsang SH. Mechanisms of neurodegeneration in a preclinical autosomal dominant retinitis pigmentosa knock-in model with a Rho D190N mutation. Cell Mol Life Sci 2019; 76:3657-3665. [PMID: 30976840 PMCID: PMC7144803 DOI: 10.1007/s00018-019-03090-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/26/2019] [Accepted: 04/01/2019] [Indexed: 11/30/2022]
Abstract
D190N, a missense mutation in rhodopsin, causes photoreceptor degeneration in patients with autosomal dominant retinitis pigmentosa (adRP). Two competing hypotheses have been developed to explain why D190N rod photoreceptors degenerate: (a) defective rhodopsin trafficking prevents proteins from correctly exiting the endoplasmic reticulum, leading to their accumulation, with deleterious effects or (b) elevated mutant rhodopsin expression and unabated signaling causes excitotoxicity. A knock-in D190N mouse model was engineered to delineate the mechanism of pathogenesis. Wild type (wt) and mutant rhodopsin appeared correctly localized in rod outer segments of D190N heterozygotes. Moreover, the rhodopsin glycosylation state in the mutants appeared similar to that in wt mice. Thus, it seems plausible that the injurious effect of the heterozygous mutation is not related to mistrafficking of the protein, but rather from constitutive rhodopsin activity and a greater propensity for chromophore isomerization even in the absence of light.
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Affiliation(s)
- Javier Sancho-Pelluz
- Neurobiología y Neurofisiología, Facultad de Medicina y Odontología, Universidad Católica de Valencia San Vicente Mártir, Valencia, Spain
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology, and Cell Biology, Columbia University, New York, NY, 10032, USA
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
| | - Xuan Cui
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology, and Cell Biology, Columbia University, New York, NY, 10032, USA
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
- Tianjin Medical University Eye Hospital, The College of Optometry, Tianjin Medical University Eye Institute, Tianjin, China
| | - Winston Lee
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
| | - Yi-Ting Tsai
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology, and Cell Biology, Columbia University, New York, NY, 10032, USA
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
- Institute of Human Nutrition and Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA
| | - Wen-Hsuan Wu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology, and Cell Biology, Columbia University, New York, NY, 10032, USA
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
- Institute of Human Nutrition and Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA
| | - Sally Justus
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology, and Cell Biology, Columbia University, New York, NY, 10032, USA
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
- Harvard Medical School, Boston, MA, USA
| | - Ilyas Washington
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
| | - Chun-Wei Hsu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology, and Cell Biology, Columbia University, New York, NY, 10032, USA
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
| | - Karen Sophia Park
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology, and Cell Biology, Columbia University, New York, NY, 10032, USA
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
| | - Susanne Koch
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology, and Cell Biology, Columbia University, New York, NY, 10032, USA
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA
- Institute of Human Nutrition and Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA
| | - Gabriel Velez
- Omics Laboratory, Stanford University, Palo Alto, CA, USA
- Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, CA, USA
- Medical Scientist Training Program, University of Iowa, Iowa City, IA, USA
| | | | - Vinit B Mahajan
- Omics Laboratory, Stanford University, Palo Alto, CA, USA
- Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, CA, USA
| | - Chyuan-Sheng Lin
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology, and Cell Biology, Columbia University, New York, NY, 10032, USA.
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York Presbyterian Hospital, 635 West 165th St, Box 212, New York, NY, 10032, USA.
- Institute of Human Nutrition and Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA.
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
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142
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Conformational Plasticity of Human Protease-Activated Receptor 1 upon Antagonist- and Agonist-Binding. Structure 2019; 27:1517-1526.e3. [PMID: 31422910 DOI: 10.1016/j.str.2019.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/07/2019] [Accepted: 07/23/2019] [Indexed: 01/14/2023]
Abstract
G protein-coupled receptors (GPCRs) show complex relationships between functional states and conformational plasticity that can be qualitatively and quantitatively described by contouring their free energy landscape. However, how ligands modulate the free energy landscape to direct conformation and function of GPCRs is not entirely understood. Here, we employ single-molecule force spectroscopy to parametrize the free energy landscape of the human protease-activated receptor 1 (PAR1), and delineate the mechanical, kinetic, and energetic properties of PAR1 being set into different functional states. Whereas in the inactive unliganded state PAR1 adopts mechanically rigid and stiff conformations, upon agonist or antagonist binding the receptor mechanically softens, while increasing its conformational flexibility, and kinetic and energetic stability. By mapping the free energy landscape to the PAR1 structure, we observe key structural regions putting this conformational plasticity into effect. Our insight, complemented with previously acquired knowledge on other GPCRs, outlines a more general framework to understand how GPCRs stabilize certain functional states.
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143
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Molecular Dynamic Simulations to Probe Water Permeation Pathways of GPCRs. Methods Mol Biol 2019. [PMID: 30969409 DOI: 10.1007/978-1-4939-9121-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Rhodopsin is a light-driven G protein-coupled receptor mediating signal transduction in eyes. The molecular dynamics (MD) simulations are powerful computational tools to investigate molecular behavior of proteins and internal water molecules which are related to the function of proteins; however, the MD simulations of the rhodopsin require several technical setups for accurate calculations. This chapter discusses practical methods for setting up the MD simulations of the rhodopsin [preparation of initial systems, condition files for MD simulation package GROMACS, and data analysis]. The data analysis includes the root mean square deviation (RMSD) and mapping of accessibility of water molecules.
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144
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Getter T, Gulati S, Zimmerman R, Chen Y, Vinberg F, Palczewski K. Stereospecific modulation of dimeric rhodopsin. FASEB J 2019; 33:9526-9539. [PMID: 31121099 PMCID: PMC6662988 DOI: 10.1096/fj.201900443rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/23/2019] [Indexed: 11/11/2022]
Abstract
The classic concept that GPCRs function as monomers has been challenged by the emerging evidence of GPCR dimerization and oligomerization. Rhodopsin (Rh) is the only GPCR whose native oligomeric arrangement was revealed by atomic force microscopy demonstrating that Rh exists as a dimer. However, the role of Rh dimerization in retinal physiology is currently unknown. In this study, we identified econazole and sulconazole, two small molecules that disrupt Rh dimer contacts, by implementing a cell-based high-throughput screening assay. Racemic mixtures of identified lead compounds were separated and tested for their stereospecific binding to Rh using UV-visible spectroscopy and intrinsic fluorescence of tryptophan (Trp) 265 after illumination. By following the changes in UV-visible spectra and Trp265 fluorescence in vitro, we found that binding of R-econazole modulates the formation of Meta III and quenches the intrinsic fluorescence of Trp265. In addition, electrophysiological ex vivo recording revealed that R-econazole slows photoresponse kinetics, whereas S-econazole decreased the sensitivity of rods without effecting the kinetics. Thus, this study contributes new methodology to identify compounds that disrupt the dimerization of GPCRs in general and validates the first active compounds that disrupt the Rh dimer specifically.-Getter, T., Gulati, S., Zimmerman, R., Chen, Y., Vinberg, F., Palczewski, K. Stereospecific modulation of dimeric rhodopsin.
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Affiliation(s)
- Tamar Getter
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California–Irvine, California, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Sahil Gulati
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California–Irvine, California, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Physiology and Biophysics, University of California–Irvine, Irvine, California, USA
| | - Remy Zimmerman
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California–Irvine, California, USA
| | - Yuanyuan Chen
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Frans Vinberg
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California–Irvine, California, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Physiology and Biophysics, University of California–Irvine, Irvine, California, USA
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145
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Varma N, Mutt E, Mühle J, Panneels V, Terakita A, Deupi X, Nogly P, Schertler GFX, Lesca E. Crystal structure of jumping spider rhodopsin-1 as a light sensitive GPCR. Proc Natl Acad Sci U S A 2019; 116:14547-14556. [PMID: 31249143 PMCID: PMC6642406 DOI: 10.1073/pnas.1902192116] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Light-sensitive G protein-coupled receptors (GPCRs)-rhodopsins-absorb photons to isomerize their covalently bound retinal, triggering conformational changes that result in downstream signaling cascades. Monostable rhodopsins release retinal upon isomerization as opposed to the retinal in bistable rhodopsins that "reisomerize" upon absorption of a second photon. Understanding the mechanistic differences between these light-sensitive GPCRs has been hindered by the scarcity of recombinant models of the latter. Here, we reveal the high-resolution crystal structure of a recombinant bistable rhodopsin, jumping spider rhodopsin-1, bound to the inverse agonist 9-cis retinal. We observe a water-mediated network around the ligand hinting toward the basis of their bistable nature. In contrast to bovine rhodopsin (monostable), the transmembrane bundle of jumping spider rhodopsin-1 as well that of the bistable squid rhodopsin adopts a more "activation-ready" conformation often observed in other nonphotosensitive class A GPCRs. These similarities suggest the role of jumping spider rhodopsin-1 as a potential model system in the study of the structure-function relationship of both photosensitive and nonphotosensitive class A GPCRs.
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Affiliation(s)
- Niranjan Varma
- Department of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, 5303 Villigen-PSI, Switzerland
- Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Eshita Mutt
- Department of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, 5303 Villigen-PSI, Switzerland
| | - Jonas Mühle
- Department of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, 5303 Villigen-PSI, Switzerland
| | - Valérie Panneels
- Department of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, 5303 Villigen-PSI, Switzerland
| | - Akihisa Terakita
- Department of Biology and Geosciences, Osaka City University, 558-8585 Osaka, Japan
| | - Xavier Deupi
- Department of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, 5303 Villigen-PSI, Switzerland
- Condensed Matter Theory Group, Laboratory for Scientific Computing and Modelling, Paul Scherrer Institute, 5303 Villigen-PSI, Switzerland
| | - Przemyslaw Nogly
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Gebhard F X Schertler
- Department of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, 5303 Villigen-PSI, Switzerland;
- Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Elena Lesca
- Department of Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute, 5303 Villigen-PSI, Switzerland;
- Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
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146
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Ropelewski P, Imanishi Y. Disrupted Plasma Membrane Protein Homeostasis in a Xenopus Laevis Model of Retinitis Pigmentosa. J Neurosci 2019; 39:5581-5593. [PMID: 31061086 PMCID: PMC6616295 DOI: 10.1523/jneurosci.3025-18.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/23/2019] [Accepted: 04/26/2019] [Indexed: 12/17/2022] Open
Abstract
Rhodopsin mislocalization is frequently observed in retinitis pigmentosa (RP) patients. For example, class I mutant rhodopsin is deficient in the VxPx trafficking signal, mislocalizes to the plasma membrane (PM) of rod photoreceptor inner segments (ISs), and causes autosomal dominant RP. Mislocalized rhodopsin causes photoreceptor degeneration in a manner independent of light-activation. In this manuscript, we took advantage of Xenopus laevis models of both sexes expressing wild-type human rhodopsin or its class I Q344ter mutant fused to Dendra2 fluorescent protein to characterize a novel light-independent mechanism of photoreceptor degeneration caused by mislocalized rhodopsin. We found that rhodopsin mislocalized to the PM is actively internalized and transported to lysosomes where it is degraded. This degradation process results in the downregulation of a crucial component of the photoreceptor IS PM: the sodium-potassium ATPase α-subunit (NKAα). The downregulation of NKAα is not because of decreased NKAα mRNA, but due to cotransport of mislocalized rhodopsin and NKAα to lysosomes or autophagolysosomes. In a separate set of experiments, we found that class I mutant rhodopsin, which causes NKAα downregulation, also causes shortening and loss of rod outer segments (OSs); the symptoms frequently observed in the early stages of human RP. Likewise, pharmacological inhibition of NKAα led to shortening and loss of rod OSs. These combined studies suggest that mislocalized rhodopsin leads to photoreceptor dysfunction through disruption of the PM protein homeostasis and compromised NKAα function. This study unveiled a novel role of lysosome-mediated degradation in causing inherited disorders manifested by mislocalization of ciliary receptors.SIGNIFICANCE STATEMENT Retinal ciliopathy is the most common form of inherited blinding disorder frequently manifesting rhodopsin mislocalization. Our understanding of the relationships between rhodopsin mislocalization and photoreceptor dysfunction/degeneration has been far from complete. This study uncovers a hitherto uncharacterized consequence of rhodopsin mislocalization: the activation of the lysosomal pathway, which negatively regulates the amount of the sodium-potassium ATPase (NKAα) on the inner segment plasma membrane. On the plasma membrane, mislocalized rhodopsin extracts NKAα and sends it to lysosomes where they are co-degraded. Compromised NKAα function leads to shortening and loss of the photoreceptor outer segments as observed for various inherited blinding disorders. In summary, this study revealed a novel pathogenic mechanism applicable to various forms of blinding disorders caused by rhodopsin mislocalization.
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Affiliation(s)
- Philip Ropelewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965
| | - Yoshikazu Imanishi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965
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147
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Hayashi F, Saito N, Tanimoto Y, Okada K, Morigaki K, Seno K, Maekawa S. Raftophilic rhodopsin-clusters offer stochastic platforms for G protein signalling in retinal discs. Commun Biol 2019; 2:209. [PMID: 31240247 PMCID: PMC6570657 DOI: 10.1038/s42003-019-0459-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 05/10/2019] [Indexed: 12/18/2022] Open
Abstract
Rhodopsin is a G protein-coupled receptor (GPCR) that initiates the phototransduction cascade in retinal disc membrane. Recent studies have suggested that rhodopsin forms highly ordered rows of dimers responsible for single-photon detection by rod photoreceptors. Dimerization is also known to confer to rhodopsin a high affinity for ordered lipids (raftophilicity). However, the role of rhodopsin organization and its raftophilicity in phototransduction remains obscure, owing to the lack of direct observation of rhodopsin dynamics and distribution in native discs. Here, we explore the single-molecule and semi-multimolecule behaviour of rhodopsin in native discs. Rhodopsin forms transient meso-scale clusters, even in darkness, which are loosely confined to the disc centre. Cognate G protein transducin co-distributes with rhodopsin, and exhibits lateral translocation to the disc periphery upon activation. We demonstrate that rhodopsin offers inherently distributed and stochastic platforms for G protein signalling by self-organizing raftophilic clusters, which continually repeat generation/extinction in the disc membrane.
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Affiliation(s)
- Fumio Hayashi
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501 Japan
| | - Natsumi Saito
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501 Japan
| | - Yasushi Tanimoto
- Research Centre for Environmental Genomics, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501 Japan
| | - Keisuke Okada
- Graduate School of Agriculture, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501 Japan
| | - Kenichi Morigaki
- Research Centre for Environmental Genomics, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501 Japan
- Graduate School of Agriculture, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501 Japan
| | - Keiji Seno
- Faculty of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192 Japan
- International Mass Imaging Centre, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192 Japan
| | - Shohei Maekawa
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501 Japan
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148
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Wen RH, Stanar P, Tam B, Moritz OL. Autophagy in Xenopus laevis rod photoreceptors is independently regulated by phototransduction and misfolded RHO P23H. Autophagy 2019; 15:1970-1989. [PMID: 30975014 DOI: 10.1080/15548627.2019.1596487] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We previously reported autophagic structures in rod photoreceptors expressing a misfolding RHO (rhodopsin) mutant (RHOP23H), suggesting that autophagy may play a role in degrading the mutant RHO and/or be involved in photoreceptor cell death. To further examine autophagy in normal and diseased rods, we generated transgenic Xenopus laevis tadpoles expressing the dually fluorescent autophagy marker mRFP-eGFP-LC3 in rods, which changes from green to yellow and finally red as autophagic structures develop and mature. Using transgenic lines with constitutive and inducible expression, we determined the time-course of autophagy in rod photoreceptors: autophagosomes last for 6 to 8 hours before fusing with lysosomes, and acidified autolysosomes last for about 28 hours before being degraded. Autophagy was diurnally regulated in normal rods, with more autophagic structures generated during periods of light, and this regulation was non-circadian. We also found that more autophagosomes were produced in rods expressing the misfolding RHOP23H mutant. The RHO chromophore absorbs photons to initiate phototransduction, and is consumed in this process; it also promotes RHO folding. To determine whether increased autophagy in light-exposed normal rods is caused by increased RHO misfolding or phototransduction, we used CRISPR/Cas9 to knock out the RPE65 and GNAT1 genes, which are essential for chromophore biosynthesis and phototransduction respectively. Both knockouts suppressed light-induced autophagy, indicating that although light and misfolded rhodopsin can both induce autophagy in rods, light-induced autophagy is not due to misfolding of RHO, but rather due to phototransduction. Abbreviations: CYCS: cytochrome c; bRHOP23H: bovine RHOP23H; Cas9: CRISPR associated protein 9; dpf: days post-fertilization; eGFP: enhanced green fluorescent protein; GNAT1: guanine nucleotide-binding protein G(t) subunit alpha-1 aka rod alpha-transducin; HSPA1A/hsp70: heat shock protein of 70 kilodaltons; LAMP1: lysosomal-associated membrane protein 1; LC3: microtubule-associated protein 1A/1B light chain 3; mRFP: monomeric red fluorescent protein; RHO: rhodopsin; RP: retinitis pigmentosa; RPE65: retinal pigment epithelium-specific 65 kDa protein: sfGFP: superfolding GFP; sgRNA: single guide RNA; WGA: wheat germ agglutinin; RHOp: the Xenopus laevis RHO.2.L promoter.
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Affiliation(s)
- Runxia H Wen
- Department of Ophthalmology and Visual Sciences, University of British Columbia , Vancouver , British Columbia , Canada
| | - Paloma Stanar
- Department of Ophthalmology and Visual Sciences, University of British Columbia , Vancouver , British Columbia , Canada
| | - Beatrice Tam
- Department of Ophthalmology and Visual Sciences, University of British Columbia , Vancouver , British Columbia , Canada
| | - Orson L Moritz
- Department of Ophthalmology and Visual Sciences, University of British Columbia , Vancouver , British Columbia , Canada
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149
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Ortega JT, Parmar T, Jastrzebska B. Flavonoids enhance rod opsin stability, folding, and self-association by directly binding to ligand-free opsin and modulating its conformation. J Biol Chem 2019; 294:8101-8122. [PMID: 30944172 DOI: 10.1074/jbc.ra119.007808] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/27/2019] [Indexed: 12/29/2022] Open
Abstract
Rhodopsin (Rho) is a visual G protein-coupled receptor expressed in the rod photoreceptors of the eye, where it mediates transmission of a light signal into a cell and converts this signal into a nerve impulse. More than 100 mutations in Rho are linked to various ocular impairments, including retinitis pigmentosa (RP). Accordingly, much effort has been directed toward developing ligands that target Rho and improve its folding and stability. Natural compounds may provide another viable approach to such drug discovery efforts. The dietary polyphenol compounds, ubiquitously present in fruits and vegetables, have beneficial effects in several eye diseases. However, the underlying mechanism of their activity is not fully understood. In this study, we used a combination of computational methods, biochemical and biophysical approaches, including bioluminescence resonance energy transfer, and mammalian cell expression systems to clarify the effects of four common bioactive flavonoids (quercetin, myricetin, and their mono-glycosylated forms quercetin-3-rhamnoside and myricetrin) on rod opsin stability, function, and membrane organization. We observed that by directly interacting with ligand-free opsin, flavonoids modulate its conformation, thereby causing faster entry of the retinal chromophore into its binding pocket. Moreover, flavonoids significantly increased opsin stability, most likely by introducing structural rigidity and promoting receptor self-association within the biological membranes. Of note, the binding of flavonoids to an RP-linked P23H opsin variant partially restored its normal cellular trafficking. Together, our results suggest that flavonoids could be utilized as lead compounds in the development of effective nonretinoid therapeutics for managing RP-related retinopathies.
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Affiliation(s)
- Joseph T Ortega
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Tanu Parmar
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Beata Jastrzebska
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
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150
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Liu H, Tang J, Du Y, Saadane A, Samuels I, Veenstra A, Kiser JZ, Palczewski K, Kern TS. Transducin1, Phototransduction and the Development of Early Diabetic Retinopathy. Invest Ophthalmol Vis Sci 2019; 60:1538-1546. [PMID: 30994864 PMCID: PMC6736377 DOI: 10.1167/iovs.18-26433] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/14/2019] [Indexed: 12/31/2022] Open
Abstract
Purpose Recent evidence suggests that retinal photoreceptor cells have an important role in the pathogenesis of retinal microvascular lesions in diabetes. We investigated the role of rod cell phototransduction on the pathogenesis of early diabetic retinopathy (DR) using Gnat1-/- mice (which causes permanent inhibition of phototransduction in rod cells without degeneration). Methods Retinal thickness, oxidative stress, expression of inflammatory proteins, electroretinograms (ERG) and optokinetic responses, and capillary permeability and degeneration were evaluated at up to 8 months of diabetes. Results The diabetes-induced degeneration of retinal capillaries was significantly inhibited in the Gnat1-/- diabetics. The effect of the Gnat1 deletion on the diabetes-induced increase in permeability showed a nonuniform accumulation of albumin in the neural retina; the defect was inhibited in diabetic Gnat1-/- mice in the inner plexiform layer (IPL), but neither in the outer plexiform (OPL) nor inner nuclear (INL) layers. In Gnat1-deficient animals, the diabetes-induced increase in expression of inflammatory associated proteins (iNOS and ICAM-1, and phosphorylation of IĸB) in the retina, and the leukocyte mediated killing of retinal endothelial cells were inhibited, however the diabetes-mediated induction of oxidative stress was not inhibited. Conclusions In conclusion, deletion of transducin1 (and the resulting inhibition of phototransduction in rod cells) inhibits the development of retinal vascular pathology in early DR.
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Affiliation(s)
- Haitao Liu
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Jie Tang
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Yunpeng Du
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Aicha Saadane
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Ivy Samuels
- Veterans Administration Medical Center Research Service 151, Cleveland, Ohio, United States
- Department of Ophthalmic Research, Cleveland Clinic, Cleveland, Ohio, United States
| | - Alex Veenstra
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Jianying Z. Kiser
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Krzysztof Palczewski
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States
| | - Timothy S. Kern
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
- Veterans Administration Medical Center Research Service 151, Cleveland, Ohio, United States
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States
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