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Kunala K, Tang JAH, Bowles Johnson KE, Huynh KT, Parkins K, Kim HJ, Yang Q, Sparrow JR, Hunter JJ. Near Infrared Autofluorescence Lifetime Imaging of Human Retinal Pigment Epithelium Using Adaptive Optics Scanning Light Ophthalmoscopy. Invest Ophthalmol Vis Sci 2024; 65:27. [PMID: 38758638 PMCID: PMC11107951 DOI: 10.1167/iovs.65.5.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 04/23/2024] [Indexed: 05/19/2024] Open
Abstract
Purpose To demonstrate the first near-infrared adaptive optics fluorescence lifetime imaging ophthalmoscopy (NIR-AOFLIO) measurements in vivo of the human retinal pigment epithelial (RPE) cellular mosaic and to visualize lifetime changes at different retinal eccentricities. Methods NIR reflectance and autofluorescence were captured using a custom adaptive optics scanning light ophthalmoscope in 10 healthy subjects (23-64 years old) at seven eccentricities and in two eyes with retinal abnormalities. Repeatability was assessed across two visits up to 8 weeks apart. Endogenous retinal fluorophores and hydrophobic whole retinal extracts of Abca4-/- pigmented and albino mice were imaged to probe the fluorescence origin of NIR-AOFLIO. Results The RPE mosaic was resolved at all locations in five of seven younger subjects (<35 years old). The mean lifetime across near-peripheral regions (8° and 12°) was longer compared to near-foveal regions (0° and 2°). Repeatability across two visits showed moderate to excellent correlation (intraclass correlation: 0.88 [τm], 0.75 [τ1], 0.65 [τ2], 0.98 [a1]). The mean lifetime across drusen-containing eyes was longer than in age-matched healthy eyes. Fluorescence was observed in only the extracts from pigmented Abca4-/- mouse. Conclusions NIR-AOFLIO was repeatable and allowed visualization of the RPE cellular mosaic. An observed signal in only the pigmented mouse extract infers the fluorescence signal originates predominantly from melanin. Variations observed across the retina with intermediate age-related macular degeneration suggest NIR-AOFLIO may act as a functional measure of a biomarker for in vivo monitoring of early alterations in retinal health.
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Affiliation(s)
- Karteek Kunala
- Center for Visual Science, University of Rochester, Rochester, New York, United States
- Byers Eye Institute, Stanford University, Palo Alto, California, United States
| | - Janet A. H. Tang
- Center for Visual Science, University of Rochester, Rochester, New York, United States
- The Institute of Optics, University of Rochester, Rochester, New York, United States
| | - Kristen E. Bowles Johnson
- Center for Visual Science, University of Rochester, Rochester, New York, United States
- Flaum Eye Institute, University of Rochester, Rochester, New York, United States
- School of Optometry, Indiana University, Bloomington, Indiana, United States
| | - Khang T. Huynh
- Center for Visual Science, University of Rochester, Rochester, New York, United States
- Department of Biomedical Engineering, University of Rochester, Rochester, New York, United States
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, Berkeley, California, United States
| | - Keith Parkins
- Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Hye-Jin Kim
- College of Pharmacy, Keimyung University, Dalseo-gu, Daegu, South Korea
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States
| | - Qiang Yang
- Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Janet R. Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States
| | - Jennifer J. Hunter
- Center for Visual Science, University of Rochester, Rochester, New York, United States
- Flaum Eye Institute, University of Rochester, Rochester, New York, United States
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
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Dontsov A, Ostrovsky M. Retinal Pigment Epithelium Pigment Granules: Norms, Age Relations and Pathology. Int J Mol Sci 2024; 25:3609. [PMID: 38612421 PMCID: PMC11011557 DOI: 10.3390/ijms25073609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/14/2024] Open
Abstract
The retinal pigment epithelium (RPE), which ensures the normal functioning of the neural retina, is a pigmented single-cell layer that separates the retina from the Bruch's membrane and the choroid. There are three main types of pigment granules in the RPE cells of the human eye: lipofuscin granules (LG) containing the fluorescent "age pigment" lipofuscin, melanoprotein granules (melanosomes, melanolysosomes) containing the screening pigment melanin and complex melanolipofuscin granules (MLG) containing both types of pigments simultaneously-melanin and lipofuscin. This review examines the functional role of pigment granules in the aging process and in the development of oxidative stress and associated pathologies in RPE cells. The focus is on the process of light-induced oxidative degradation of pigment granules caused by reactive oxygen species. The reasons leading to increased oxidative stress in RPE cells as a result of the oxidative degradation of pigment granules are considered. A mechanism is proposed to explain the phenomenon of age-related decline in melanin content in RPE cells. The essence of the mechanism is that when the lipofuscin part of the melanolipofuscin granule is exposed to light, reactive oxygen species are formed, which destroy the melanin part. As more melanolipofuscin granules are formed with age and the development of degenerative diseases, the melanin in pigmented epithelial cells ultimately disappears.
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Affiliation(s)
| | - Mikhail Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia;
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3
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Fontaine V, Boumedine T, Monteiro E, Fournié M, Gersende G, Sahel JA, Picaud S, Veillet S, Lafont R, Latil M, Dilda PJ, Camelo S. RAR Inhibitors Display Photo-Protective and Anti-Inflammatory Effects in A2E Stimulated RPE Cells In Vitro through Non-Specific Modulation of PPAR or RXR Transactivation. Int J Mol Sci 2024; 25:3037. [PMID: 38474284 PMCID: PMC10932305 DOI: 10.3390/ijms25053037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/23/2024] [Accepted: 03/02/2024] [Indexed: 03/14/2024] Open
Abstract
N-retinylidene-N-retinylethanolamine (A2E) has been associated with age-related macular degeneration (AMD) physiopathology by inducing cell death, angiogenesis and inflammation in retinal pigmented epithelial (RPE) cells. It was previously thought that the A2E effects were solely mediated via the retinoic acid receptor (RAR)-α activation. However, this conclusion was based on experiments using the RAR "specific" antagonist RO-41-5253, which was found to also be a ligand and partial agonist of the peroxisome proliferator-activated receptor (PPAR)-γ. Moreover, we previously reported that inhibiting PPAR and retinoid X receptor (RXR) transactivation with norbixin also modulated inflammation and angiogenesis in RPE cells challenged in the presence of A2E. Here, using several RAR inhibitors, we deciphered the respective roles of RAR, PPAR and RXR transactivations in an in vitro model of AMD. We showed that BMS 195614 (a selective RAR-α antagonist) displayed photoprotective properties against toxic blue light exposure in the presence of A2E. BMS 195614 also significantly reduced the AP-1 transactivation and mRNA expression of the inflammatory interleukin (IL)-6 and vascular endothelial growth factor (VEGF) induced by A2E in RPE cells in vitro, suggesting a major role of RAR in these processes. Surprisingly, however, we showed that (1) Norbixin increased the RAR transactivation and (2) AGN 193109 (a high affinity pan-RAR antagonist) and BMS 493 (a pan-RAR inverse agonist), which are photoprotective against toxic blue light exposure in the presence of A2E, also inhibited PPARs transactivation and RXR transactivation, respectively. Therefore, in our in vitro model of AMD, several commercialized RAR inhibitors appear to be non-specific, and we propose that the phototoxicity and expression of IL-6 and VEGF induced by A2E in RPE cells operates through the activation of PPAR or RXR rather than by RAR transactivation.
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Affiliation(s)
- Valérie Fontaine
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Thinhinane Boumedine
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Elodie Monteiro
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Mylène Fournié
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Gendre Gersende
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
- Fondation Ophtalmologique Rothschild, 29 rue Manin, 75019 Paris, France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Serge Picaud
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France; (V.F.); (T.B.); (M.F.); (J.-A.S.); (S.P.)
| | - Stanislas Veillet
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
| | - René Lafont
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
| | - Mathilde Latil
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
| | - Pierre J. Dilda
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
| | - Serge Camelo
- Biophytis, Sorbonne Université, BC9, 4 place Jussieu, 75005 Paris, France (M.L.); (P.J.D.)
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Feldman T, Yakovleva M, Utina D, Ostrovsky M. Short-Term and Long-Term Effects after Exposure to Ionizing Radiation and Visible Light on Retina and Retinal Pigment Epithelium of Mouse Eye. Int J Mol Sci 2023; 24:17049. [PMID: 38069372 PMCID: PMC10707529 DOI: 10.3390/ijms242317049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/25/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
A comparative in vivo study of the effects of ionizing radiation (accelerated protons) and visible light (400-700 nm) on the retina and retinal pigment epithelium (RPE) of the mouse eye was carried out. Using the methods of fluorescence spectroscopy and high-performance liquid chromatography (HPLC), we analyzed the relative composition of retinoids in chloroform extracts obtained from the retinas and RPEs immediately after exposure of animals to various types of radiation and 4.5 months after they were exposed and maintained under standard conditions throughout the period. The fluorescent properties of chloroform extracts were shown to change upon exposure to various types of radiation. This fact indicates the accumulation of retinoid oxidation and degradation products in the retina and RPE. The data from fluorescence and HPLC analyses of retinoids indicate that when exposed to ionizing radiation, retinoid oxidation processes similar to photooxidation occur. Both ionizing radiation and high-intensity visible light have been shown to be characterized by long-term effects. The action of any type of radiation is assumed to activate the mechanism of enhanced reactive oxygen species production, resulting in a long-term damaging effect.
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Affiliation(s)
- Tatiana Feldman
- Department of Biology, Lomonosov Moscow State University, Leninskiye Gory 1, Moscow 119234, Russia;
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, Moscow 119334, Russia;
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, Moscow 119334, Russia
| | - Marina Yakovleva
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, Moscow 119334, Russia;
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, Moscow 119334, Russia
| | - Dina Utina
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna 141980, Russia;
| | - Mikhail Ostrovsky
- Department of Biology, Lomonosov Moscow State University, Leninskiye Gory 1, Moscow 119234, Russia;
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, Moscow 119334, Russia;
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, Moscow 119334, Russia
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5
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Shome I, Thathapudi NC, Aramati BMR, Kowtharapu BS, Jangamreddy JR. Stages, pathogenesis, clinical management and advancements in therapies of age-related macular degeneration. Int Ophthalmol 2023; 43:3891-3909. [PMID: 37347455 DOI: 10.1007/s10792-023-02767-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 06/08/2023] [Indexed: 06/23/2023]
Abstract
Age-related macular degeneration (AMD) is a retinal degenerative disorder prevalent in the elderly population, which leads to the loss of central vision. The disease progression can be managed, if not prevented, either by blocking neovascularization ("wet" form of AMD) or by preserving retinal pigment epithelium and photoreceptor cells ("dry" form of AMD). Although current therapeutic modalities are moderately successful in delaying the progression and management of the disease, advances over the past years in regenerative medicine using iPSC, embryonic stem cells, advanced materials (including nanomaterials) and organ bio-printing show great prospects in restoring vision and efficient management of either forms of AMD. This review focuses on the molecular mechanism of the disease, model systems (both cellular and animal) used in studying AMD, the list of various regenerative therapies and the current treatments available. The article also highlights on the recent clinical trials using regenerative therapies and management of the disease.
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Affiliation(s)
- Ishita Shome
- UR Advanced Therapeutics Private Limited, ASPIRE-BioNest, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, India
| | - Neethi C Thathapudi
- Centre de Recherche Hôpital Maisonneuve-Rosemont, Montréal, QC, Canada
- Department of Ophthalmology and Institute of Biomedical Engineering, Université de Montréal, Montréal, QC, Canada
| | - Bindu Madhav Reddy Aramati
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, India
| | - Bhavani S Kowtharapu
- UR Advanced Therapeutics Private Limited, ASPIRE-BioNest, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, India
| | - Jaganmohan R Jangamreddy
- UR Advanced Therapeutics Private Limited, ASPIRE-BioNest, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, India.
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6
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Abstract
Endogenous photosensitizers play a critical role in both beneficial and harmful light-induced transformations in biological systems. Understanding their mode of action is essential for advancing fields such as photomedicine, photoredox catalysis, environmental science, and the development of sun care products. This review offers a comprehensive analysis of endogenous photosensitizers in human skin, investigating the connections between their electronic excitation and the subsequent activation or damage of organic biomolecules. We gather the physicochemical and photochemical properties of key endogenous photosensitizers and examine the relationships between their chemical reactivity, location within the skin, and the primary biochemical events following solar radiation exposure, along with their influence on skin physiology and pathology. An important take-home message of this review is that photosensitization allows visible light and UV-A radiation to have large effects on skin. The analysis presented here unveils potential causes for the continuous increase in global skin cancer cases and emphasizes the limitations of current sun protection approaches.
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Affiliation(s)
- Erick L Bastos
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Frank H Quina
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
- Department of Chemical Engineering, Polytechnic School, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Maurício S Baptista
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
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7
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Kim HJ, Zhao J, Walewski JL, Sparrow JR. A High Fat Diet Fosters Elevated Bisretinoids. J Biol Chem 2023; 299:104784. [PMID: 37146972 DOI: 10.1016/j.jbc.2023.104784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 04/28/2023] [Accepted: 04/29/2023] [Indexed: 05/07/2023] Open
Abstract
High dietary fat intake is associated with metabolic dysregulation, but little is known regarding the effects of a high fat diet (HFD) on photoreceptor cell functioning. We explored the intersection of a high fat diet (HFD) and the visual cycle adducts that form in photoreceptor cells by non-enzymatic reactions. In black C57BL/6J mice and albino C57BL/6Jc2j mice raised on a high fat diet until age 3, 6 or 12 months, chromatographically quantified bisretinoids were increased relative to mice on a standard diet. In vivo measurement of fundus autofluorescence, the source of which is bisretinoid, also revealed a significant increase in the HFD-mice. Additionally, mice provided with a diet high in fat presented with elevated retinol-binding protein 4 (RBP4) the protein responsible for transporting retinol in plasma. Vitamin A was elevated in plasma although not in ocular tissue. Bisretinoids form in photoreceptor cell outer segments by random reactions of retinaldehyde with phosphatidylethanolamine. We found that the latter phospholipid was significantly increased in mice fed a HFD versus mice on a control diet. In leptin-deficient ob/ob mice, a genetic model of obesity, plasma levels of Rbp4 protein were higher but bisretinoids in retina were not elevated. Photoreceptor cell viability measured as outer nuclear layer thickness was reduced in the ob/ob mice relative to wild-type. The accelerated formation of bisretinoid we observed in diet induced obese mice is related to the high fat intake and to increased delivery of vitamin A to the visual cycle.
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Affiliation(s)
- Hye Jin Kim
- Departments of Ophthalmology, Columbia University Medical Center, 635 W. 165(th) Street, New York NY, 10032
| | - Jin Zhao
- Departments of Ophthalmology, Columbia University Medical Center, 635 W. 165(th) Street, New York NY, 10032
| | - Jose L Walewski
- Departments of Medicine, Columbia University Medical Center, 635 W. 165(th) Street, New York NY, 10032
| | - Janet R Sparrow
- Departments of Ophthalmology, Columbia University Medical Center, 635 W. 165(th) Street, New York NY, 10032; Departments of Pathology and Cell Biology, Columbia University Medical Center, 635 W. 165(th) Street, New York NY, 10032.
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Protein-Mediated Carotenoid Delivery Suppresses the Photoinducible Oxidation of Lipofuscin in Retinal Pigment Epithelial Cells. Antioxidants (Basel) 2023; 12:antiox12020413. [PMID: 36829973 PMCID: PMC9952040 DOI: 10.3390/antiox12020413] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
Lipofuscin of retinal pigment epithelium (RPE) cells is a complex heterogeneous system of chromophores which accumulates as granules during the cell's lifespan. Lipofuscin serves as a source of various cytotoxic effects linked with oxidative stress. Several age-related eye diseases such as macular degeneration of the retina, as well as some severe inherited eye pathologies, are accompanied by a significant increase in lipofuscin granule concentration. The accumulation of carotenoids in the RPE could provide an effective antioxidant protection against lipofuscin cytotoxic manifestations. Given the highly lipophilic nature of carotenoids, their targeted delivery to the vulnerable tissues can potentially be assisted by special proteins. In this study, we demonstrate how protein-mediated delivery of zeaxanthin using water-soluble Bombyx mori carotenoid-binding protein (BmCBP-ZEA) suppresses the photoinducible oxidative stress in RPE cells caused by irradiation of lipofuscin with intense white light. We implemented fluorescence lifetime imaging of the RPE cell culture ARPE-19 fed with lipofuscin granules and then irradiated by white light with and without the addition of BmCBP-ZEA. We demonstrate that after irradiation the mean fluorescence lifetime of lipofuscin significantly increases, while the presence of BmCBP-ZEA at 200 nM concentration suppresses the increase in the average lifetime of lipofuscin fluorescence, indicating an approx. 35% inhibition of the oxidative stress. This phenomenon serves as indirect yet important evidence of the efficiency of the protein-mediated carotenoid delivery into pigment epithelium cells.
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Lee SJ, Roh YJ, Kim JE, Jin YJ, Song HJ, Seol A, Park SH, Douangdeuane B, Souliya O, Choi SI, Hwang DY. Protective Effects of Dipterocarpus tuberculatus in Blue Light-Induced Macular Degeneration in A2E-Laden ARPE19 Cells and Retina of Balb/c Mice. Antioxidants (Basel) 2023; 12:antiox12020329. [PMID: 36829888 PMCID: PMC9952417 DOI: 10.3390/antiox12020329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/22/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Natural products with significant antioxidant activity have been receiving attention as one of the treatment strategies to prevent age-related macular degeneration (AMD). Reactive oxygen intermediates (ROI) including oxo-N-retinylidene-N-retinylethanolamine (oxo-A2E) and singlet oxygen-induced damage, are believed to be one of the major causes of the development of AMD. To investigate the therapeutic effects of methanol extracts of Dipterocarpus tuberculatus Roxb. (MED) against blue light (BL)-caused macular degeneration, alterations in the antioxidant activity, apoptosis pathway, neovascularization, inflammatory response, and retinal degeneration were analyzed in A2E-laden ARPE19 cells and Balb/c mice after exposure of BL. Seven bioactive components, including 2α-hydroxyursolic acid, ε-viniferin, asiatic acid, bergenin, ellagic acid, gallic acid and oleanolic acid, were detected in MED. MED exhibited high DPPH and ABTS free radical scavenging activity. BL-induced increases in intracellular reactive oxygen species (ROS) production and nitric oxide (NO) concentration were suppressed by MED treatment. A significant recovery of antioxidant capacity by an increase in superoxide dismutase enzyme (SOD) activity, SOD expression levels, and nuclear factor erythroid 2-related factor 2 (NRF2) expression were detected as results of MED treatment effects. The activation of the apoptosis pathway, the expression of neovascular proteins, cyclooxygenase-2 (COX-2)-induced inducible nitric oxide synthase (iNOS) mediated pathway, inflammasome activation, and expression of inflammatory cytokines was remarkably inhibited in the MED treated group compared to the Vehicle-treated group in the AMD cell model. Furthermore, MED displayed protective effects in BL-induced retinal degeneration through improvement in the thickness of the whole retina, outer nuclear layer (ONL), inner nuclear layer (INL), and photoreceptor layer (PL) in Balb/c mice. Taken together, these results indicate that MED exhibits protective effects in BL-induced retinal degeneration and has the potential in the future to be developed as a treatment option for dry AMD with atrophy of retinal pigment epithelial (RPE) cells.
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Affiliation(s)
- Su Jin Lee
- Department of Biomaterials Science (BK21 FOUR Program), Life and Industry Convergence Research Institute, College of Natural Resources and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | - Yu Jeong Roh
- Department of Biomaterials Science (BK21 FOUR Program), Life and Industry Convergence Research Institute, College of Natural Resources and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | - Ji Eun Kim
- Department of Biomaterials Science (BK21 FOUR Program), Life and Industry Convergence Research Institute, College of Natural Resources and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | - You Jeong Jin
- Department of Biomaterials Science (BK21 FOUR Program), Life and Industry Convergence Research Institute, College of Natural Resources and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | - Hee Jin Song
- Department of Biomaterials Science (BK21 FOUR Program), Life and Industry Convergence Research Institute, College of Natural Resources and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | - Ayun Seol
- Department of Biomaterials Science (BK21 FOUR Program), Life and Industry Convergence Research Institute, College of Natural Resources and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | - So Hae Park
- Department of Biomaterials Science (BK21 FOUR Program), Life and Industry Convergence Research Institute, College of Natural Resources and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | | | - Onevilay Souliya
- Institute of Traditional Medicine, Ministry of Health, Vientiane 0103, Laos
| | - Sun Il Choi
- School of Pharmacy, Henan University, Kaifeng 475004, China
- Correspondence: (S.I.C.); (D.Y.H.); Tel.: +86-13271140312 (S.I.C.); +82-55-350-5388 (D.Y.H.)
| | - Dae Youn Hwang
- Department of Biomaterials Science (BK21 FOUR Program), Life and Industry Convergence Research Institute, College of Natural Resources and Life Science, Pusan National University, Miryang 50463, Republic of Korea
- Longevity & Wellbeing Research Center, Laboratory Animals Resources Center, College of Natural Resources and Life Science, Pusan National University, Miryang 50463, Republic of Korea
- Correspondence: (S.I.C.); (D.Y.H.); Tel.: +86-13271140312 (S.I.C.); +82-55-350-5388 (D.Y.H.)
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Chromophore hydrolysis and release from photoactivated rhodopsin in native membranes. Proc Natl Acad Sci U S A 2022; 119:e2213911119. [PMID: 36322748 PMCID: PMC9659404 DOI: 10.1073/pnas.2213911119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
For sustained vision, photoactivated rhodopsin (Rho*) must undergo hydrolysis and release of all-trans-retinal, producing substrate for the visual cycle and apo-opsin available for regeneration with 11-cis-retinal. The kinetics of this hydrolysis has yet to be described for rhodopsin in its native membrane environment. We developed a method consisting of simultaneous denaturation and chromophore trapping by isopropanol/borohydride, followed by exhaustive protein digestion, complete extraction, and liquid chromatography-mass spectrometry. Using our method, we tracked Rho* hydrolysis, the subsequent formation of N-retinylidene-phosphatidylethanolamine (N-ret-PE) adducts with the released all-trans-retinal, and the reduction of all-trans-retinal to all-trans-retinol. We found that hydrolysis occurred faster in native membranes than in detergent micelles typically used to study membrane proteins. The activation energy of the hydrolysis in native membranes was determined to be 17.7 ± 2.4 kcal/mol. Our data support the interpretation that metarhodopsin II, the signaling state of rhodopsin, is the primary species undergoing hydrolysis and release of its all-trans-retinal. In the absence of NADPH, free all-trans-retinal reacts with phosphatidylethanolamine (PE), forming a substantial amount of N-ret-PE (∼40% of total all-trans-retinal at physiological pH), at a rate that is an order of magnitude faster than Rho* hydrolysis. However, N-ret-PE formation was highly attenuated by NADPH-dependent reduction of all-trans-retinal to all-trans-retinol. Neither N-ret-PE formation nor all-trans-retinal reduction affected the rate of hydrolysis of Rho*. Our study provides a comprehensive picture of the hydrolysis of Rho* and the release of all-trans-retinal and its reentry into the visual cycle, a process in which alteration can lead to severe retinopathies.
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Ng ESY, Kady N, Hu J, Dave A, Jiang Z, Pei J, Gorin MB, Matynia A, Radu RA. Membrane Attack Complex Mediates Retinal Pigment Epithelium Cell Death in Stargardt Macular Degeneration. Cells 2022; 11:3462. [PMID: 36359858 PMCID: PMC9655712 DOI: 10.3390/cells11213462] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/28/2022] [Accepted: 10/30/2022] [Indexed: 08/22/2023] Open
Abstract
Recessive Stargardt disease (STGD1) is an inherited retinopathy caused by mutations in the ABCA4 gene. The ABCA4 protein is a phospholipid-retinoid flippase in the outer segments of photoreceptors and the internal membranes of retinal pigment epithelial (RPE) cells. Here, we show that RPE cells derived via induced pluripotent stem-cell from a molecularly and clinically diagnosed STGD1 patient exhibited reduced ABCA4 protein and diminished activity compared to a normal subject. Consequently, STGD1 RPE cells accumulated intracellular autofluorescence-lipofuscin and displayed increased complement C3 activity. The level of C3 inversely correlated with the level of CD46, an early negative regulator of the complement cascade. Persistent complement dysregulation led to deposition of the membrane attack complex on the surface of RPE cells, decrease in transepithelial resistance, and subsequent cell death. These findings are strong evidence of complement-mediated RPE cell damage in STGD1, in the absence of photoreceptors, caused by reduced CD46 regulatory protein.
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Affiliation(s)
- Eunice Sze Yin Ng
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
- Molecular Cellular and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, CA 90095, USA
| | - Nermin Kady
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109, USA
- Clinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Jane Hu
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Arpita Dave
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Zhichun Jiang
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Jacqueline Pei
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Michael B. Gorin
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Anna Matynia
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Roxana A. Radu
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
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12
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Feldman T, Ostrovskiy D, Yakovleva M, Dontsov A, Borzenok S, Ostrovsky M. Lipofuscin-Mediated Photic Stress Induces a Dark Toxic Effect on ARPE-19 Cells. Int J Mol Sci 2022; 23:12234. [PMID: 36293088 PMCID: PMC9602730 DOI: 10.3390/ijms232012234] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 12/25/2023] Open
Abstract
Lipofuscin granules from retinal pigment epithelium (RPE) cells contain bisretinoid fluorophores, which are photosensitizers and are phototoxic to cells. In the presence of oxygen, bisretinoids are oxidized to form various products, containing aldehydes and ketones, which are also potentially cytotoxic. In a prior study, we identified that bisretinoid oxidation and degradation products have both hydrophilic and amphiphilic properties, allowing their diffusion through the lipofuscin granule membrane into the RPE cell cytoplasm, and are thiobarbituric acid (TBA)-active. The purpose of the present study was to determine if these products exhibit a toxic effect to the RPE cell also in the absence of light. The experiments were performed using the lipofuscin-fed ARPE-19 cell culture. The RPE cell viability analysis was performed with the use of flow cytofluorimetry and laser scanning confocal microscopy. The results obtained indicated that the cell viability of the lipofuscin-fed ARPE-19 sample was clearly reduced not immediately after visible light irradiation for 18 h, but after 4 days maintaining in the dark. Consequently, we could conclude that bisretinoid oxidation products have a damaging effect on the RPE cell in the dark and can be considered as an aggravating factor in age-related macular degeneration progression.
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Affiliation(s)
- Tatiana Feldman
- Department of Biology, Lomonosov Moscow State University, Leninskiye Gory 1, 119234 Moscow, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, 119334 Moscow, Russia
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, 119334 Moscow, Russia
| | - Dmitriy Ostrovskiy
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, 119334 Moscow, Russia
- Sv. Fyodorov Eye Microsurgery Complex, 59a Beskudnikovsky bld., 127486 Moscow, Russia
| | - Marina Yakovleva
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, 119334 Moscow, Russia
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, 119334 Moscow, Russia
| | - Alexander Dontsov
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, 119334 Moscow, Russia
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, 119334 Moscow, Russia
| | - Sergey Borzenok
- Sv. Fyodorov Eye Microsurgery Complex, 59a Beskudnikovsky bld., 127486 Moscow, Russia
| | - Mikhail Ostrovsky
- Department of Biology, Lomonosov Moscow State University, Leninskiye Gory 1, 119234 Moscow, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, 119334 Moscow, Russia
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, 119334 Moscow, Russia
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13
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Feldman TB, Dontsov AE, Yakovleva MA, Ostrovsky MA. Photobiology of lipofuscin granules in the retinal pigment epithelium cells of the eye: norm, pathology, age. Biophys Rev 2022; 14:1051-1065. [PMID: 36124271 PMCID: PMC9481861 DOI: 10.1007/s12551-022-00989-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/26/2022] [Indexed: 01/10/2023] Open
Abstract
Lipofuscin granules (LGs) are accumulated in the retinal pigment epithelium (RPE) cells. The progressive LG accumulation can somehow lead to pathology and accelerate the aging process. The review examines composition, spectral properties and photoactivity of LGs isolated from the human cadaver eyes. By use of atomic force microscopy and near-field microscopy, we have revealed the fluorescent heterogeneity of LGs. We have discovered the generation of reactive oxygen species by LGs, and found that LGs and melanolipofuscin granules are capable of photoinduced oxidation of lipids. It was shown that A2E, as the main fluorophore (bisretinoid) of LGs, is much less active as an oxidation photosensitizer than other fluorophores (bisretinoids) of LGs. Photooxidized products of bisretinoids pose a much greater danger to the cell than non-oxidized one. Our studies of the fluorescent properties of LGs and their fluorophores (bisretinoids) showed for the first time that their spectral characteristics change (shift to the short-wavelength region) in pathology and after exposure to ionizing radiation. By recording the fluorescence spectra and fluorescence decay kinetics of oxidized products of LG fluorophores, it is possible to improve the methods of early diagnosis of degenerative diseases. Lipofuscin ("aging pigment") is not an inert "slag". The photoactivity of LGs can pose a significant danger to the RPE cells. Fluorescence characteristics of LGs are a tool to detect early stages of degeneration in the retina and RPE.
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Affiliation(s)
- T. B. Feldman
- Department of Biology, Lomonosov Moscow State University, Moscow, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - A. E. Dontsov
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - M. A. Yakovleva
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - M. A. Ostrovsky
- Department of Biology, Lomonosov Moscow State University, Moscow, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
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14
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Kim HJ, Zhao J, Sparrow JR. Vitamin A aldehyde-taurine adducts function in photoreceptor cells. Redox Biol 2022; 54:102386. [PMID: 35809434 PMCID: PMC9287728 DOI: 10.1016/j.redox.2022.102386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/17/2022] [Accepted: 06/24/2022] [Indexed: 01/12/2023] Open
Abstract
To facilitate the movement of retinoids through the visual cycle and to limit nonspecific chemical reaction, multiple mechanisms are utilized to handle these molecules when not contained within the binding pocket of opsin. Vitamin A aldehyde is sequestered by reversible Schiff base formation with phosphatidylethanolamine (PE) and subsequently undergoes NADPH-dependent reduction. Otherwise inefficient handling of retinaldehyde can lead to the formation of fluorescent di-retinal compounds within the outer segments of photoreceptor cells. These bisretinoid fluorophores initiate photooxidative processes having adverse consequences for retina. Various carrier proteins confer water solubility and maintain the 11-cis-retinoid configuration. Mechanisms for sequestration of retinoid include the formation of a reversible Schiff base between retinaldehyde and taurine (A1-taurine, A1T), the most abundant amino acid in photoreceptor cells. Here we have undertaken to examine the effects of taurine depletion using the transport inhibitors guanidinoethyl sulfonate (GES) and β-alanine. Oral treatment of BALB/cJ mice with β-alanine reduced ocular A1T and the mice exhibited significantly lower scotopic and photopic a-wave amplitudes. As a secondary effect of retinal degeneration, A1T was not detected and taurine was significantly reduced in mice carrying a P23H opsin mutation. The thinning of ONL that is indicative of reduced photoreceptor cell viability in albino Abca4-/- mice was more pronounced in β-alanine treated mice. Treatment of agouti and albino Abca4-/- mice with β-alanine and GES was associated with reduced bisretinoid measured chromatographically. Consistent with a reduction in carbonyl scavenging activity by taurine, methylglyoxal-adducts were also increased in the presence of β-alanine. Taken together these findings support the postulate that A1T serves as a reservoir of vitamin A aldehyde, with diminished A1T explaining reduced photoreceptor light-sensitivity, accentuated ONL thinning in Abca4-/- mice and attenuated bisretinoid formation.
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Affiliation(s)
- Hye Jin Kim
- Departments of Ophthalmology and Columbia University Medical Center, New York, NY, 10032, USA
| | - Jin Zhao
- Departments of Ophthalmology and Columbia University Medical Center, New York, NY, 10032, USA
| | - Janet R. Sparrow
- Departments of Ophthalmology and Columbia University Medical Center, New York, NY, 10032, USA,Departments of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, 10032, USA,Corresponding author. Departments of Ophthalmology and Columbia University Medical Center, New York, NY, 10032, USA.
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15
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Yakovleva MA, Radchenko AS, Kostyukov AA, Chagovets VV, Kononikhin AS, Khubetsova MK, Borzenok SA, Kuzmin VA, Nikolaev EN, Feldman TB, Ostrovsky MA. Comparative Analysis of the Physicochemical Characteristics of Fluorophore Groups of Lipofuscin Granules from Cells of Retinal Pigmental Epithhelium of Human Cadader Eyes in the Norm and in a Pathology. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2022. [DOI: 10.1134/s199079312201033x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Protective Effect of a Water-Soluble Carotenoid-Rich Extract of Cordyceps militaris against Light-Evoked Functional Vision Deterioration in Mice. Nutrients 2022; 14:nu14081675. [PMID: 35458237 PMCID: PMC9031935 DOI: 10.3390/nu14081675] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/13/2022] [Accepted: 04/15/2022] [Indexed: 01/27/2023] Open
Abstract
Light-evoked retinal photodamage is considered an important factor contributing to functional vision deterioration and can even lead to light maculopathy or dry age-related macular degeneration. Loss of visual acuity (VA) and visual contrast sensitivity function (VCSF) are the major symptoms of retinal degenerative diseases. Cordyceps militaris is a carotenoid-rich Chinese medicinal fungus with antioxidant, anti-inflammatory, and immunomodulatory functions. C. militaris extract is a natural substance, and its bioactive constituents have been shown to confer health benefits, but their application in retinal tissue and functional vision protection in vivo remain incompletely understood. In the present study, we evaluated the influence of water-soluble, carotenoid-rich C. militaris extracts on the visual performance of light-damaged mouse retinas in vivo, using adult female CD-1® (ICR) albino mice. We showed that oral administration of this C. militaris extract (10 mg/kg, twice daily) protected the neural retina tissue against light-evoked photoreceptor cell death, reduced Müller cell hypertrophic gliosis, and elevated GSH levels and promoted the recovery of VA- and VCSF-thresholds, especially for high spatial frequency-characterized vision. These results suggest that, probably because of its water-soluble carotenoids, C. militaris extract has the potential to prevent or treat light-induced visual dysfunction.
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17
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The Age-Related Macular Degeneration (AMD)-Preventing Mechanism of Natural Products. Processes (Basel) 2022. [DOI: 10.3390/pr10040678] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Age-related macular degeneration (AMD) is related to central visual loss in elderly people and, based on the increment in the percentage of the aging population, the number of people suffering from AMD could increase. AMD is initiated by retinal pigment epithelium (RPE) cell death, finally leading to neovascularization in the macula lutea. AMD is an uncurable disease, but the symptom can be suppressed. The current therapy of AMD can be classified into four types: device-based treatment, anti-inflammatory drug treatment, anti-vascular endothelial growth factor treatment, and natural product treatment. All these therapies have adverse effects, however early AMD therapy used with products has several advantages, as it can prevent RPE cell apoptosis in safe doses. Cell death (apoptosis) is caused by various factors, such as oxidative stress, inflammation, carbonyl stress, and a deficiency in essential components for cells, and RPE cell death is related to oxidative stress, inflammation, and carbonyl stress. Some natural products have anti-oxidative effects, anti-inflammation effects, and/or anti-carbonylation effects. The AMD preventive mechanism of natural products varies, with some natural products activating one or more anti-apoptotic pathways, such as the Nrf2/HO-1 anti-oxidative pathway, the anti-inflammasome pathway, and the anti-carbonyl pathway. As AMD drug candidates from natural products effectively inhibit RPE cell death, they have the potential to be developed as drugs for preventing early (dry) AMD.
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18
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Fang Y, Taubitz T, Tschulakow AV, Heiduschka P, Szewczyk G, Burnet M, Peters T, Biesemeier A, Sarna T, Schraermeyer U, Julien-Schraermeyer S. Removal of RPE lipofuscin results in rescue from retinal degeneration in a mouse model of advanced Stargardt disease: Role of reactive oxygen species. Free Radic Biol Med 2022; 182:132-149. [PMID: 35219849 DOI: 10.1016/j.freeradbiomed.2022.02.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/17/2022] [Accepted: 02/22/2022] [Indexed: 11/30/2022]
Abstract
Accumulation of lipofuscin in the retinal pigment epithelium (RPE) is a hallmark of aging and is associated with retinal degeneration encountered in age-related macular degeneration (AMD) and Stargardt disease (SD). Currently, treatment for lipofuscin-induced retinal degeneration is unavailable. Here, we report that Remofuscin (INN: soraprazan, a tetrahydropyridoether small molecule) reverses lipofuscin accumulation in aged primary human RPE cells and is non-cytotoxic in aged SD mouse RPE cells in vitro. In addition, we show that the removal of lipofuscin after a single intravitreal injection of Remofuscin results in a rescue from retinal degeneration in a mouse model of advanced SD which is even accompanied by an amelioration of the retinal dysfunction. Finally, we demonstrate that the mechanism causing lipofuscinolysis may involve the reactive oxygen species generated via the presence of Remofuscin. These data suggest a possible therapeutic approach to untreatable lipofuscin-mediated diseases like AMD, SD and lipofuscinopathies in neurodegenerative diseases.
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Affiliation(s)
- Yuan Fang
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Tatjana Taubitz
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Alexander V Tschulakow
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany; STZ Ocutox, Preclinical Drug Assessment, Hechingen, Germany
| | - Peter Heiduschka
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Grzegorz Szewczyk
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | | | - Tobias Peters
- Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Antje Biesemeier
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Ulrich Schraermeyer
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany; STZ Ocutox, Preclinical Drug Assessment, Hechingen, Germany
| | - Sylvie Julien-Schraermeyer
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany; STZ Ocutox, Preclinical Drug Assessment, Hechingen, Germany.
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19
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Dontsov A, Yakovleva M, Trofimova N, Sakina N, Gulin A, Aybush A, Gostev F, Vasin A, Feldman T, Ostrovsky M. Water-Soluble Products of Photooxidative Destruction of the Bisretinoid A2E Cause Proteins Modification in the Dark. Int J Mol Sci 2022; 23:ijms23031534. [PMID: 35163454 PMCID: PMC8836230 DOI: 10.3390/ijms23031534] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/21/2022] [Accepted: 01/26/2022] [Indexed: 01/06/2023] Open
Abstract
Aging of the retina is accompanied by a sharp increase in the content of lipofuscin granules and bisretinoid A2E in the cells of the retinal pigment epithelium (RPE) of the human eye. It is known that A2E can have a toxic effect on RPE cells. However, the specific mechanisms of the toxic effect of A2E are poorly understood. We investigated the effect of the products of photooxidative destruction of A2E on the modification of bovine serum albumin (BSA) and hemoglobin from bovine erythrocytes. A2E was irradiated with a blue light-emitting diode (LED) source (450 nm) or full visible light (400–700 nm) of a halogen lamp, and the resulting water-soluble products of photooxidative destruction were investigated for the content of carbonyl compounds by mass spectrometry and reaction with thiobarbituric acid. It has been shown that water-soluble products formed during A2E photooxidation and containing carbonyl compounds cause modification of serum albumin and hemoglobin, measured by an increase in fluorescence intensity at 440–455 nm. The antiglycation agent aminoguanidine inhibited the process of modification of proteins. It is assumed that water-soluble carbonyl products formed as a result of A2E photodestruction led to the formation of modified proteins, activation of the inflammation process, and, as a consequence, to the progression of various senile eye pathologies.
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Affiliation(s)
- Alexander Dontsov
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia; (M.Y.); (N.T.); (N.S.); (T.F.); (M.O.)
- Correspondence: ; +7-495-939-7422
| | - Marina Yakovleva
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia; (M.Y.); (N.T.); (N.S.); (T.F.); (M.O.)
| | - Natalia Trofimova
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia; (M.Y.); (N.T.); (N.S.); (T.F.); (M.O.)
| | - Natalia Sakina
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia; (M.Y.); (N.T.); (N.S.); (T.F.); (M.O.)
| | - Alexander Gulin
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia; (A.G.); (A.A.); (F.G.); (A.V.)
| | - Arseny Aybush
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia; (A.G.); (A.A.); (F.G.); (A.V.)
| | - Fedor Gostev
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia; (A.G.); (A.A.); (F.G.); (A.V.)
| | - Alexander Vasin
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia; (A.G.); (A.A.); (F.G.); (A.V.)
| | - Tatiana Feldman
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia; (M.Y.); (N.T.); (N.S.); (T.F.); (M.O.)
- Department of Biology, Lomonosov Moscow State University, Leninskiye Gory 1, 119234 Moscow, Russia
| | - Mikhail Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia; (M.Y.); (N.T.); (N.S.); (T.F.); (M.O.)
- Department of Biology, Lomonosov Moscow State University, Leninskiye Gory 1, 119234 Moscow, Russia
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20
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Lipofuscin Granule Bisretinoid Oxidation in the Human Retinal Pigment Epithelium forms Cytotoxic Carbonyls. Int J Mol Sci 2021; 23:ijms23010222. [PMID: 35008647 PMCID: PMC8745408 DOI: 10.3390/ijms23010222] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/16/2021] [Accepted: 12/22/2021] [Indexed: 01/06/2023] Open
Abstract
Age-related macular degeneration (AMD) is the primary cause of central blindness among the elderly. AMD is associated with progressive accumulation of lipofuscin granules in retinal pigment epithelium (RPE) cells. Lipofuscin contains bisretinoid fluorophores, which are photosensitizers and are phototoxic to RPE and neuroretinal cells. In the presence of oxygen, bisretinoids are also oxidized, forming various products, consisting primarily of aldehydes and ketones, which are also potentially cytotoxic. In a prior study, we identified that in AMD, bisretinoid oxidation products are increased in RPE lipofuscin granules. The purpose of the present study was to determine if these products were toxic to cellular structures. The physicochemical characteristics of bisretinoid oxidation products in lipofuscin, which were obtained from healthy donor eyes, were studied. Raman spectroscopy and time-of-flight secondary ion mass spectrometry (ToF–SIMS) analysis identified the presence of free-state aldehydes and ketones within the lipofuscin granules. Together, fluorescence spectroscopy, high-performance liquid chromatography, and mass spectrometry revealed that bisretinoid oxidation products have both hydrophilic and amphiphilic properties, allowing their diffusion through lipofuscin granule membrane into the RPE cell cytoplasm. These products contain cytotoxic carbonyls, which can modify cellular proteins and lipids. Therefore, bisretinoid oxidation products are a likely aggravating factor in the pathogenesis of AMD.
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21
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Yakovleva MA, Feldman TB, Lyakhova KN, Utina DM, Kolesnikova IA, Vinogradova YV, Molokanov AG, Ostrovsky MA. Ionized Radiation-Mediated Retinoid Oxidation in the Retina and Retinal Pigment Epithelium of the Murine Eye. Radiat Res 2021; 197:270-279. [PMID: 34879150 DOI: 10.1667/rade-21-00069.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/15/2021] [Indexed: 11/03/2022]
Abstract
The present study evaluated the effects of proton and gamma-ray ionizing radiation on the mouse eye. The aim of this work was to analyze radiation-mediated retinoid oxidation in the retina and retinal pigment epithelium (RPE). The findings from this analysis can be used to develop a noninvasive method for rapid assessment of the effects of ionizing radiation. Comparative fluorescence and chromatographic analyses of retinoids before and after irradiations were performed. The fluorescent properties of chloroform extracts from irradiated mouse retina and RPE exhibited an increase in fluorescence intensity in the short-wave region of the spectrum (λ < 550 nm). This change is due to increased retinal and RPE retinoid oxidation and degradation products after radiation exposure. Comparative analyses of radiation effects demonstrated that the effect of proton exposure on the retina and RPE was higher than that of gamma-ray exposure. The present study revealed a new approach to assessing the level of radiation exposure in ocular tissues.
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Affiliation(s)
- Marina A Yakovleva
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - Tatiana B Feldman
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia.,Department of Molecular Physiology, Biological Faculty, Moscow State University, Moscow, Russia
| | - Kristina N Lyakhova
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow region, Russia
| | - Dina M Utina
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow region, Russia
| | - Inna A Kolesnikova
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow region, Russia
| | - Yuliya V Vinogradova
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow region, Russia
| | - Alexander G Molokanov
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow region, Russia
| | - Mikhail A Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia.,Department of Molecular Physiology, Biological Faculty, Moscow State University, Moscow, Russia.,Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow region, Russia
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22
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Zhang D, Robinson K, Washington I. C20D3-Vitamin A Prevents Retinal Pigment Epithelium Atrophic Changes in a Mouse Model. Transl Vis Sci Technol 2021; 10:8. [PMID: 34878528 PMCID: PMC8662574 DOI: 10.1167/tvst.10.14.8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Purpose This study aimed to evaluate the contribution of vitamin A dimerization to retinal pigment epithelium (RPE) atrophic changes. Leading causes of irreversible blindness, including Stargardt disease and age-related macular degeneration (AMD), occur as a result of atrophic changes in RPE. The cause of the RPE atrophic changes is not apparent. During the vitamin A cycle, vitamin A dimerizes, leading to vitamin A cycle byproducts, such as vitamin A dimers, in the RPE. Methods To study the consequence of vitamin A dimerization to RPE atrophic changes, we used a rodent model with accelerated vitamin A dimerization, Abca4−/−/Rdh8−/− mice, and the vitamin A analog C20D3-vitamin A to selectively ameliorate the accelerated rate of vitamin A dimerization. Results We show that ameliorating the rate of vitamin A dimerization with C20D3-vitamin A mitigates pathological changes observed in the prodromal phase of the most prevalent retinal degenerative diseases, including fundus autofluorescence changes, dark adaptation delays, and signature RPE atrophic changes. Conclusions Data demonstrate that the dimerization of vitamin A during the vitamin A cycle is sufficient alone to cause the prerequisite RPE atrophic changes thought to be responsible for the leading causes of irreversible blindness and that correcting the dimerization rate with C20D3-vitamin A may be sufficient to prevent the RPE atrophic changes. Translational Relevance Preventing the dimerization of vitamin A with the vitamin A analog C20D3-vitamin A may be sufficient to alter the clinical course of the most prevalent forms of blindness, including Stargardt disease and age-related macular degeneration (AMD).
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Affiliation(s)
- Dan Zhang
- Columbia University Medical Center, Ophthalmology, New York, NY, USA
| | - Kiera Robinson
- Columbia University Medical Center, Ophthalmology, New York, NY, USA
| | - Ilyas Washington
- Columbia University Medical Center, Ophthalmology, New York, NY, USA.,biOOrg3.14, Buffalo, WY, USA
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23
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Zhang D, Mihai DM, Washington I. Vitamin A cycle byproducts explain retinal damage and molecular changes thought to initiate retinal degeneration. Biol Open 2021; 10:273577. [PMID: 34842275 PMCID: PMC8649638 DOI: 10.1242/bio.058600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 09/03/2021] [Indexed: 01/24/2023] Open
Abstract
In the most prevalent retinal diseases, including Stargardt disease and age-related macular degeneration (AMD), byproducts of vitamin A form in the retina abnormally during the vitamin A cycle. Despite evidence of their toxicity, whether these vitamin A cycle byproducts contribute to retinal disease, are symptoms, beneficial, or benign has been debated. We delivered a representative vitamin A byproduct, A2E, to the rat's retina and monitored electrophysiological, histological, proteomic, and transcriptomic changes. We show that the vitamin A cycle byproduct is sufficient alone to damage the RPE, photoreceptor inner and outer segments, and the outer plexiform layer, cause the formation of sub-retinal debris, alter transcription and protein synthesis, and diminish retinal function. The presented data are consistent with the theory that the formation of vitamin A byproducts during the vitamin A cycle is neither benign nor beneficial but may be sufficient alone to cause the most prevalent forms of retinal disease. Retarding the formation of vitamin A byproducts could potentially address the root cause of several retinal diseases to eliminate the threat of irreversible blindness for millions of people. Summary: During the vitamin A cycle, byproducts of vitamin A form in the eye. Using a rat model, we show that the byproducts alone can explain several retinal derangements observed in the prodromal phase of human retinal disease. Retarding the formation of these byproducts may address the root cause of the most prevalent retinal diseases.
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Affiliation(s)
- Dan Zhang
- Columbia University Medical Center, Ophthalmology, New York, NY 10032, USA
| | - Doina M Mihai
- Columbia University Medical Center, Ophthalmology, New York, NY 10032, USA
| | - Ilyas Washington
- Columbia University Medical Center, Ophthalmology, New York, NY 10032, USA.,biOOrg3.14, Buffalo, WY 82834, USA
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24
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A2E-induced inflammation and angiogenesis in RPE cells in vitro are modulated by PPAR-α, -β/δ, -γ, and RXR antagonists and by norbixin. Aging (Albany NY) 2021; 13:22040-22058. [PMID: 34544906 PMCID: PMC8507260 DOI: 10.18632/aging.203558] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 09/03/2021] [Indexed: 12/15/2022]
Abstract
N-retinylidene-N-retinylethanolamine (A2E) plays a central role in age-related macular degeneration (AMD) by inducing angiogenesis and inflammation. A2E effects are mediated at least partly via the retinoic acid receptor (RAR)-α. Here we show that A2E binds and transactivates also peroxisome proliferator-activated receptors (PPAR) and retinoid X receptors (RXR). 9’-cis-norbixin, a di-apocarotenoid is also a ligand of these nuclear receptors (NR). Norbixin inhibits PPAR and RXR transactivation induced by A2E. Moreover, norbixin reduces protein kinase B (AKT) phosphorylation, NF-κB and AP-1 transactivation and mRNA expression of the inflammatory interleukins (IL) -6 and -8 and of vascular endothelial growth factor (VEGF) enhanced by A2E. By contrast, norbixin increases matrix metalloproteinase 9 (MMP9) and C-C motif chemokine ligand 2 (CCL2) mRNA expression in response to A2E. Selective PPAR-α, -β/δ and –γ antagonists inhibit the expression of IL-6 and IL-8 while only the antagonist of PPAR-γ inhibits the transactivation of NF-κB following A2E exposure. In addition, a cocktail of all three PPARs antagonists and also HX531, an antagonist of RXR reproduce norbixin effects on inflammation. Altogether, A2E’s deleterious biological effects could be inhibited through PPAR and RXR regulation. Moreover, the modulation of these NR by norbixin may open new avenues for the treatment of AMD.
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25
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Kim HJ, Montenegro D, Zhao J, Sparrow JR. Bisretinoids of the Retina: Photo-Oxidation, Iron-Catalyzed Oxidation, and Disease Consequences. Antioxidants (Basel) 2021; 10:antiox10091382. [PMID: 34573014 PMCID: PMC8467448 DOI: 10.3390/antiox10091382] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 01/06/2023] Open
Abstract
The retina and, in particular, retinal pigment epithelial cells are unusual for being encumbered by exposure to visible light, while being oxygen-rich, and also amassing photoreactive molecules. These fluorophores (bisretinoids) are generated as a byproduct of the activity of vitamin A aldehyde-the chromophore necessary for vision. Bisretinoids form in photoreceptor cells due to random reactions of two molecules of vitamin A aldehyde with phosphatidylethanolamine; bisretinoids are subsequently transferred to retinal pigment epithelial (RPE) cells, where they accumulate in the lysosomal compartment with age. Bisretinoids can generate reactive oxygen species by both energy and electron transfer, and they become photo-oxidized and photolyzed in the process. While these fluorescent molecules are accrued by RPE cells of all healthy eyes, they are also implicated in retinal disease.
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Affiliation(s)
- Hye Jin Kim
- Department of Ophthalmology, Columbia University Medical Center, 635 W., 165th Str., New York, NY 10032, USA; (H.J.K.); (D.M.); (J.Z.)
| | - Diego Montenegro
- Department of Ophthalmology, Columbia University Medical Center, 635 W., 165th Str., New York, NY 10032, USA; (H.J.K.); (D.M.); (J.Z.)
| | - Jin Zhao
- Department of Ophthalmology, Columbia University Medical Center, 635 W., 165th Str., New York, NY 10032, USA; (H.J.K.); (D.M.); (J.Z.)
| | - Janet R. Sparrow
- Department of Ophthalmology, Columbia University Medical Center, 635 W., 165th Str., New York, NY 10032, USA; (H.J.K.); (D.M.); (J.Z.)
- Department of Pathology and Cell Biology, Columbia University Medical Center, 635 W., 165th Str., New York, NY 10032, USA
- Correspondence: ; Tel.: +1-212-305-9944
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26
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Arunkumar R, Gorusupudi A, Li B, Blount JD, Nwagbo U, Kim HJ, Sparrow JR, Bernstein PS. Lutein and zeaxanthin reduce A2E and iso-A2E levels and improve visual performance in Abca4 -/-/Bco2 -/- double knockout mice. Exp Eye Res 2021; 209:108680. [PMID: 34161819 PMCID: PMC8595537 DOI: 10.1016/j.exer.2021.108680] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/08/2021] [Accepted: 06/17/2021] [Indexed: 10/21/2022]
Abstract
Accumulation of bisretinoids such as A2E and its isomer iso-A2E is thought to mediate blue light-induced oxidative damage associated with age-related macular degeneration (AMD) and autosomal recessive Stargardt disease (STGD1). We hypothesize that increasing dietary intake of the macular carotenoids lutein and zeaxanthin in individuals at risk of AMD and STGD1 can inhibit the formation of bisretinoids A2E and iso-A2E, which can potentially ameliorate macular degenerative diseases. To study the beneficial effect of macular carotenoids in a retinal degenerative diseases model, we used ATP-binding cassette, sub-family A member 4 (Abca4-/-)/β,β-carotene-9',10'-oxygenase 2 (Bco2-/-) double knockout (KO) mice that accumulate elevated levels of A2E and iso-A2E in the retinal pigment epithelium (RPE) and macular carotenoids in the retina. Abca4-/-/Bco2-/- and Abca4-/- mice were fed a lutein-supplemented chow, zeaxanthin-supplemented chow or placebo chow (~2.6 mg of carotenoid/mouse/day) for three months. Visual function and electroretinography (ERG) were measured after one month and three months of carotenoid supplementation. The lutein and zeaxanthin supplemented Abca4-/-/Bco2-/- mice had significantly lower levels of RPE/choroid A2E and iso-A2E compared to control mice fed with placebo chow and improved visual performance. Carotenoid supplementation in Abca4-/- mice minimally raised retinal carotenoid levels and did not show much difference in bisretinoid levels or visual function compared to the control diet group. There was a statistically significant inverse correlation between carotenoid levels in the retina and A2E and iso-A2E levels in the RPE/choroid. Supplementation with retinal carotenoids, especially zeaxanthin, effectively inhibits bisretinoid formation in a mouse model of STGD1 genetically enhanced to accumulate carotenoids in the retina. These results provide further impetus to pursue oral carotenoids as therapeutic interventions for STGD1 and AMD.
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Affiliation(s)
- Ranganathan Arunkumar
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Aruna Gorusupudi
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Binxing Li
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - J David Blount
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Uzoamaka Nwagbo
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Hye Jin Kim
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Paul S Bernstein
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA.
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27
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Butler JM, Supharattanasitthi W, Yang YC, Paraoan L. RNA-seq analysis of ageing human retinal pigment epithelium: Unexpected up-regulation of visual cycle gene transcription. J Cell Mol Med 2021; 25:5572-5585. [PMID: 33934486 PMCID: PMC8184696 DOI: 10.1111/jcmm.16569] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/07/2021] [Accepted: 04/09/2021] [Indexed: 02/06/2023] Open
Abstract
Ageing presents adverse effects on the retina and is the primary risk factor for age‐related macular degeneration (AMD). We report the first RNA‐seq analysis of age‐related transcriptional changes in the human retinal pigment epithelium (RPE), the primary site of AMD pathogenesis. Whole transcriptome sequencing of RPE from human donors ranging in age from 31 to 93 reveals that ageing is associated with increasing transcription of main RPE‐associated visual cycle genes (including LRAT, RPE65, RDH5, RDH10, RDH11; pathway enrichment BH‐adjusted P = 4.6 × 10−6). This positive correlation is replicated in an independent set of 28 donors and a microarray dataset of 50 donors previously published. LRAT expression is positively regulated by retinoid by‐products of the visual cycle (A2E and all‐trans‐retinal) involving modulation by retinoic acid receptor alpha transcription factor. The results substantiate a novel age‐related positive feedback mechanism between accumulation of retinoid by‐products in the RPE and the up‐regulation of visual cycle genes.
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Affiliation(s)
- Joe M Butler
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Wasu Supharattanasitthi
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Yit C Yang
- Department of Ophthalmology, Wolverhampton Eye Infirmary, New Cross Hospital, Wolverhampton, UK
| | - Luminita Paraoan
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
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28
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Kim HJ, Sparrow JR. Bisretinoid phospholipid and vitamin A aldehyde: shining a light. J Lipid Res 2021; 62:100042. [PMID: 32371567 PMCID: PMC7933493 DOI: 10.1194/jlr.tr120000742] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/29/2020] [Indexed: 12/17/2022] Open
Abstract
Vitamin A aldehyde covalently bound to opsin protein is embedded in a phospholipid-rich membrane that supports photon absorption and phototransduction in photoreceptor cell outer segments. Following absorption of a photon, the 11-cis-retinal chromophore of visual pigment in photoreceptor cells isomerizes to all-trans-retinal. To maintain photosensitivity 11-cis-retinal must be replaced. At the same time, however, all-trans-retinal has to be handled so as to prevent nonspecific aldehyde activity. Some molecules of retinaldehyde upon release from opsin are efficiently reduced to retinol. Other molecules are released into the lipid phase of the disc membrane where they form a conjugate [N-retinylidene-PE (NRPE)] through a Schiff base linkage with PE. The reversible formation of NRPE serves as a transient sink for retinaldehyde that is intended to return retinaldehyde to the visual cycle. However, if instead of hydrolyzing to PE and retinaldehyde, NRPE reacts with a second molecule of retinaldehyde, a synthetic pathway is initiated that leads to the formation of multiple species of unwanted bisretinoid fluorophores. We report on recently identified members of the bisretinoid family, some of which differ with respect to the acyl chains associated with the glycerol backbone. We discuss processing of the lipid moieties of these fluorophores in lysosomes of retinal pigment epithelial cells, their fluorescence characters, and new findings related to light- and iron-associated oxidation of bisretinoids.
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Affiliation(s)
- Hye Jin Kim
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY, USA.
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29
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Pham TNM, Shin CY, Park SH, Lee TH, Ryu HY, Kim SB, Auh K, Jeong KW. Solanum melongena L. Extract Protects Retinal Pigment Epithelial Cells from Blue Light-Induced Phototoxicity in In Vitro and In Vivo Models. Nutrients 2021; 13:nu13020359. [PMID: 33503991 PMCID: PMC7912168 DOI: 10.3390/nu13020359] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 01/04/2021] [Accepted: 01/15/2021] [Indexed: 01/05/2023] Open
Abstract
N-retinylidene-N-retinylethanolamine (A2E) accumulation in the retina is a prominent marker of retinal degenerative diseases. Blue light exposure is considered as an important factor contributing to dry age-related macular degeneration (AMD). Eggplant and its constituents have been shown to confer health benefits, but their therapeutic effects on dry AMD remain incompletely understood. In this study, we showed that an extract of Solanum melongena L. (EPX) protected A2E-laden ARPE-19 cells against blue light-induced cell death via attenuating reactive oxygen species. Transcriptomic analysis demonstrated that blue light modulated the expression of genes associated with stress response, inflammation, and cell death, and EPX suppressed the inflammatory pathway induced by blue light in A2E-laden ARPE-19 cells by inhibiting the nuclear translocation of nuclear factor kappa B and transcription of pro-inflammatory genes (CXCL8 and IL1B). The degradation of intracellular A2E was considered the major mechanism underlying the protective effect of EPX. Moreover, chlorogenic acid isolated from EPX exerted protective effects against blue light-induced cell damage in A2E-laden ARPE-19 cells. In vivo, EPX administration in BALB/c mice reduced the fundus damage and degeneration of the retinal layer in a blue light-induced retinal damage model. Collectively, our findings suggest the potential role of Solanum melongena L. extract for AMD treatment.
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Affiliation(s)
- Thu Nguyen Minh Pham
- Gachon Research Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 21936, Korea; (T.N.M.P.); (C.-Y.S.)
- Department of Pharmacognosy, Faculty of Pharmacy, Hong Bang International University, Ho Chi Minh 215, Vietnam
| | - Chae-Young Shin
- Gachon Research Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 21936, Korea; (T.N.M.P.); (C.-Y.S.)
| | - Seo Hyun Park
- R&D Center, Ahn-Gook Health Co., Ltd., Seoul 06164, Korea; (S.H.P.); (T.H.L.); (K.A.)
| | - Taek Hwan Lee
- R&D Center, Ahn-Gook Health Co., Ltd., Seoul 06164, Korea; (S.H.P.); (T.H.L.); (K.A.)
| | - Hyeon Yeol Ryu
- Korea Conformity Laboratories, Incheon 21999, Korea; (H.Y.R.); (S.-B.K.)
| | - Sung-Bae Kim
- Korea Conformity Laboratories, Incheon 21999, Korea; (H.Y.R.); (S.-B.K.)
| | - Kwang Auh
- R&D Center, Ahn-Gook Health Co., Ltd., Seoul 06164, Korea; (S.H.P.); (T.H.L.); (K.A.)
| | - Kwang Won Jeong
- Gachon Research Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 21936, Korea; (T.N.M.P.); (C.-Y.S.)
- Correspondence: ; Tel.: +82-32-820-4925; Fax: +82-32-820-4829
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30
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Zhao J, Kim HJ, Ueda K, Zhang K, Montenegro D, Dunaief JL, Sparrow JR. A vicious cycle of bisretinoid formation and oxidation relevant to recessive Stargardt disease. J Biol Chem 2021; 296:100259. [PMID: 33837742 PMCID: PMC7948646 DOI: 10.1016/j.jbc.2021.100259] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/09/2020] [Accepted: 01/05/2021] [Indexed: 11/29/2022] Open
Abstract
The ability of iron to transfer electrons enables the contribution of this metal to a variety of cellular activities even as the redox properties of iron are also responsible for the generation of hydroxyl radicals (•OH), the most destructive of the reactive oxygen species. We previously showed that iron can promote the oxidation of bisretinoid by generating highly reactive hydroxyl radical (•OH). Now we report that preservation of iron regulation in the retina is not sufficient to prevent iron-induced bisretinoid oxidative degradation when blood iron levels are elevated in liver-specific hepcidin knockout mice. We obtained evidence for the perpetuation of Fenton reactions in the presence of the bisretinoid A2E and visible light. On the other hand, iron chelation by deferiprone was not associated with changes in postbleaching recovery of 11-cis-retinal or dark-adapted ERG b-wave amplitudes indicating that the activity of Rpe65, a rate-determining visual cycle protein that carries an iron-binding domain, is not affected. Notably, iron levels were elevated in the neural retina and retinal pigment epithelial (RPE) cells of Abca4−/− mice. Consistent with higher iron content, ferritin-L immunostaining was elevated in RPE of a patient diagnosed with ABCA4-associated disease and in RPE and photoreceptor cells of Abca4−/− mice. In neural retina of the mutant mice, reduced Tfrc mRNA was also an indicator of retinal iron overload. Thus iron chelation may defend retina when bisretinoid toxicity is implicated in disease processes.
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Affiliation(s)
- Jin Zhao
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, USA
| | - Hye Jin Kim
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, USA
| | - Keiko Ueda
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, USA
| | - Kevin Zhang
- Department of Ophthalmology, University of Pennsylvania, Philadelphia Pennsylvania, USA
| | - Diego Montenegro
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, USA
| | - Joshua L Dunaief
- Department of Ophthalmology, University of Pennsylvania, Philadelphia Pennsylvania, USA
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, USA; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, USA.
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31
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Moine E, Boukhallat M, Cia D, Jacquemot N, Guillou L, Durand T, Vercauteren J, Brabet P, Crauste C. New lipophenols prevent carbonyl and oxidative stresses involved in macular degeneration. Free Radic Biol Med 2021; 162:367-382. [PMID: 33129975 DOI: 10.1016/j.freeradbiomed.2020.10.316] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/17/2022]
Abstract
Dry age-related macular degeneration and Stargardt disease undergo a known toxic mechanism caused by carbonyl and oxidative stresses (COS). This is responsible for accumulation in the retinal pigment epithelium (RPE) of A2E, a main toxic pyridinium bis-retinoid lipofuscin component. Previous studies have shown that carbonyl stress in retinal cells could be reduced by an alkyl-phloroglucinol-DHA conjugate (lipophenol). Here, we performed a rational design of different families of lipophenols to conserve anti-carbonyl stress activities and improve antioxidant properties. Five synthetic pathways leading to alkyl-(poly)phenol derivatives, with phloroglucinol, resveratrol, catechin and quercetin as the main backbone, linked to poly-unsaturated fatty acid, are presented. These lipophenols were evaluated in ARPE-19 cell line for their anti-COS properties and a structure-activity relationship study is proposed. Protection of ARPE-19 cells against A2E toxicity was assessed for the four best candidates. Finally, interesting anti-COS properties of the most promising quercetin lipophenol were confirmed in primary RPE cells.
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Affiliation(s)
- Espérance Moine
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, CNRS, ENSCM, Montpellier, 34093, France.
| | - Manel Boukhallat
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, CNRS, ENSCM, Montpellier, 34093, France
| | - David Cia
- Laboratoire de Biophysique Neurosensorielle, UMR INSERM 1107, Facultés de Médecine et de Pharmacie, Clermont-Ferrand, 63000, France
| | - Nathalie Jacquemot
- Laboratoire de Biophysique Neurosensorielle, UMR INSERM 1107, Facultés de Médecine et de Pharmacie, Clermont-Ferrand, 63000, France
| | - Laurent Guillou
- Institut des Neurosciences de Montpellier, INSERM U1051, Université de Montpellier, Montpellier, 34091, France
| | - Thierry Durand
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, CNRS, ENSCM, Montpellier, 34093, France
| | - Joseph Vercauteren
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, CNRS, ENSCM, Montpellier, 34093, France
| | - Philippe Brabet
- Institut des Neurosciences de Montpellier, INSERM U1051, Université de Montpellier, Montpellier, 34091, France
| | - Céline Crauste
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, CNRS, ENSCM, Montpellier, 34093, France.
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32
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Schmitz-Valckenberg S, Pfau M, Fleckenstein M, Staurenghi G, Sparrow JR, Bindewald-Wittich A, Spaide RF, Wolf S, Sadda SR, Holz FG. Fundus autofluorescence imaging. Prog Retin Eye Res 2020; 81:100893. [PMID: 32758681 DOI: 10.1016/j.preteyeres.2020.100893] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/20/2020] [Accepted: 07/25/2020] [Indexed: 12/20/2022]
Abstract
Fundus autofluorescence (FAF) imaging is an in vivo imaging method that allows for topographic mapping of naturally or pathologically occurring intrinsic fluorophores of the ocular fundus. The dominant sources are fluorophores accumulating as lipofuscin in lysosomal storage bodies in postmitotic retinal pigment epithelium cells as well as other fluorophores that may occur with disease in the outer retina and subretinal space. Photopigments of the photoreceptor outer segments as well as macular pigment and melanin at the fovea and parafovea may act as filters of the excitation light. FAF imaging has been shown to be useful with regard to understanding of pathophysiological mechanisms, diagnostics, phenotype-genotype correlation, identification of prognostic markers for disease progression, and novel outcome parameters to assess efficacy of interventional strategies in chorio-retinal diseases. More recently, the spectrum of FAF imaging has been expanded with increasing use of green in addition to blue FAF, introduction of spectrally-resolved FAF, near-infrared FAF, quantitative FAF imaging and fluorescence life time imaging (FLIO). This article gives an overview of basic principles, FAF findings in various retinal diseases and an update on recent developments.
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Affiliation(s)
- Steffen Schmitz-Valckenberg
- Department of Ophthalmology, University of Bonn, Bonn, Germany; John A. Moran Eye Center, University of Utah, Salt Lake City, USA
| | - Maximilian Pfau
- Department of Ophthalmology, University of Bonn, Bonn, Germany; Department of Biomedical Data Science, Stanford University, USA
| | | | - Giovanni Staurenghi
- Department of Biomedical and Clinical Science "Luigi Sacco", Luigi Sacco Hospital University of Milan, Italy
| | - Janet R Sparrow
- Departments of Ophthalmology and Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Almut Bindewald-Wittich
- Department of Ophthalmology, University of Bonn, Bonn, Germany; Augenheilkunde Heidenheim MVZ, Heidenheim, Germany
| | - Richard F Spaide
- Vitreous Retina Macula Consultants of New York, New York, NY, USA
| | - Sebastian Wolf
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Srinivas R Sadda
- Doheny Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany.
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33
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Yakovleva MA, Radchenko AS, Kostyukov AA, Arbukhanova PM, Borzenok SA, Kuzmin VA, Feldman TB, Ostrovsky MA. Reconstruction of the Fluorescence Spectra of Bisretinoids and the Products of Their Photooxidation and Photodegradation from the Retinal Pigment Epithelium of the Human Eye. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2020. [DOI: 10.1134/s199079312003029x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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34
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Yakovleva MA, Radchenko AS, Feldman TB, Kostyukov AA, Arbukhanova PM, Borzenok SA, Kuzmin VA, Ostrovsky MA. Fluorescence characteristics of lipofuscin fluorophores from human retinal pigment epithelium. Photochem Photobiol Sci 2020; 19:920-930. [PMID: 32441276 DOI: 10.1039/c9pp00406h] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Lipofuscin granules accumulate in the retinal pigment epithelium (RPE) with age, especially in patients with visual diseases, including progressive age-related macular degeneration (AMD). Bisretinoids and their photooxidation and photodegradation products are major sources of lipofuscin granule fluorescence. The present study focused on examining the fluorescence decay characteristics of bisretinoid photooxidation and photodegradation products to evaluate the connection between fluorescence lifetime and spectral characteristics of target fluorophore groups. The primary objective of the study was to apply experimental spectral analysis results of lipofuscin granule fluorescence properties to interpretation of fluorescence lifetime imaging ophthalmoscopy data. Fluorescence analysis of the lipofuscin granule fluorophores in RPE collected from cadaver eyes was performed. The fluorescence lifetimes were measured by picosecond-resolved time correlated single photon counting technique. A global analytical method was applied to analyze data sets. The photooxidation and photodegradation products of bisretinoids exhibited a longer fluorescence lifetime (average value approximately 6 ns) and a shorter wavelength maximum (530-580 nm). Further, these products significantly contributed (more than 30%), to total fluorescence compared to the other fluorophores in lipofuscin granules. Thus, the contribution of oxidized lipofuscin bisretinoids to autofluorescence decay kinetics is an important characteristic for fluorescence lifetime imaging microscopy data analysis. The higher average fluorescence lifetime in AMD eyes was likely due to the higher abundance of oxidized bisretinoids compared with non-oxidized bisretinoids. Because higher level of oxidized bisretinoids is indicative of pathological processes in the retina and RPE, the present findings have the potential to improve fluorescence lifetime imaging approaches for early diagnosis of degenerative processes in the retina and RPE.
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Affiliation(s)
- Marina A Yakovleva
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia
| | - Alexandra Sh Radchenko
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia
| | - Tatiana B Feldman
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia.,Department of Molecular Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, 119991, Moscow, Russia
| | - Alexey A Kostyukov
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia
| | - Patimat M Arbukhanova
- Sv. Fyodorov Eye Microsurgery Complex, Beskudnikovsky bld. 59a, 127486, Moscow, Russia
| | - Sergey A Borzenok
- Sv. Fyodorov Eye Microsurgery Complex, Beskudnikovsky bld. 59a, 127486, Moscow, Russia
| | - Vladimir A Kuzmin
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia
| | - Mikhail A Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia.,Department of Molecular Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, 119991, Moscow, Russia
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35
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Fontaine V, Monteiro E, Fournié M, Brazhnikova E, Boumedine T, Vidal C, Balducci C, Guibout L, Latil M, Dilda PJ, Veillet S, Sahel JA, Lafont R, Camelo S. Systemic administration of the di-apocarotenoid norbixin (BIO201) is neuroprotective, preserves photoreceptor function and inhibits A2E and lipofuscin accumulation in animal models of age-related macular degeneration and Stargardt disease. Aging (Albany NY) 2020; 12:6151-6171. [PMID: 32255762 PMCID: PMC7185133 DOI: 10.18632/aging.103014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/02/2020] [Indexed: 12/31/2022]
Abstract
Atrophic A\age-related macular degeneration (AMD) and Stargardt disease (STGD) are major blinding diseases affecting millions of patients worldwide, but no treatment is available. In dry AMD and STGD oxidative stress and subretinal accumulation of N-retinylidene-N-retinylethanolamine (A2E), a toxic by-product of the visual cycle, causes retinal pigment epithelium (RPE) and photoreceptor degeneration leading to visual impairment. Acute and chronic retinal degeneration following blue light damage (BLD) in BALB/c mice and aging of Abca4-/- Rdh8-/- mice, respectively, reproduce features of AMD and STGD. Efficacy of systemic administrations of 9'-cis-norbixin (norbixin), a natural di-apocarotenoid, prepared from Bixa orellana seeds with anti-oxidative properties, was evaluated during BLD in BALB/c mice, and in Abca4-/- Rdh8-/- mice of different ages, following three experimental designs: “preventive”, “early curative” and “late curative” supplementations. Norbixin injected intraperitoneally in BALB/c mice, maintained scotopic and photopic electroretinogram amplitude and was neuroprotective. Norbixin chronic oral administration for 6 months in Abca4-/- Rdh8-/- mice following the “early curative” supplementation showed optimal neuroprotection and maintenance of photoreceptor function and reduced ocular A2E accumulation. Thus, norbixin appears promising as a systemic drug candidate for both AMD and STGD treatment.
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Affiliation(s)
- Valérie Fontaine
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - Elodie Monteiro
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - Mylène Fournié
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - Elena Brazhnikova
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | | | - Cécile Vidal
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - Christine Balducci
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Louis Guibout
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Mathilde Latil
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Pierre J Dilda
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Stanislas Veillet
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - René Lafont
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Serge Camelo
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
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Li S, Green JF, Jin M. Impacts of deletion and ichthyosis prematurity syndrome-associated mutations in fatty acid transport protein 4 on the function of RPE65. FEBS Lett 2019; 594:540-552. [PMID: 31595490 DOI: 10.1002/1873-3468.13633] [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: 08/28/2019] [Revised: 09/16/2019] [Accepted: 09/16/2019] [Indexed: 12/23/2022]
Abstract
The retinal pigment epithelium-specific 65 kDa (RPE65) isomerase plays a pivotal role in photoreceptor survival and function. RPE65-catalyzed synthesis of 11-cis-retinol from all-trans-retinyl esters in the visual cycle is negatively regulated, through a heretofore unknown mechanism, by the fatty acid transport protein FATP4, mutations in which are associated with ichthyosis prematurity syndrome (IPS). Here, we analyzed the interaction between deletion mutants of FATP4 and RPE65 and the impacts of IPS-associated FATP4 mutations on RPE65 expression, 11-cis-retinol synthesis, and all-trans-retinyl ester synthesis. Our results suggest that the interaction between FATP4 and RPE65 contributes to the inhibition of RPE65 function and that IPS-associated nonsense and missense mutations in FATP4 have different effects on the visual cycle.
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Affiliation(s)
- Songhua Li
- Neuroscience Center of Excellence, Louisiana State University School of Medicine, New Orleans, LA, USA
| | - John F Green
- Neuroscience Center of Excellence, Louisiana State University School of Medicine, New Orleans, LA, USA
| | - Minghao Jin
- Neuroscience Center of Excellence, Louisiana State University School of Medicine, New Orleans, LA, USA.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, LA, USA
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37
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Lessons learned from quantitative fundus autofluorescence. Prog Retin Eye Res 2019; 74:100774. [PMID: 31472235 DOI: 10.1016/j.preteyeres.2019.100774] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/21/2019] [Accepted: 08/25/2019] [Indexed: 12/12/2022]
Abstract
Quantitative fundus autofluorescence (qAF) is an approach that is built on a confocal scanning laser platform and used to measure the intensity of the inherent autofluorescence of retina elicited by short-wavelength (488 nm) excitation. Being non-invasive, qAF does not interrupt tissue architecture, thus allowing for structural correlations. The spectral features, cellular origin and topographic distribution of the natural autofluorescence of the fundus indicate that it is emitted from retinaldehyde-adducts that form in photoreceptor cells and accumulate, under most conditions, in retinal pigment epithelial cells. The distributions and intensities of fundus autofluorescence deviate from normal in many retinal disorders and it is widely recognized that these changing patterns can aid in the diagnosis and monitoring of retinal disease. The standardized protocol employed by qAF involves the normalization of fundus grey levels to a fluorescent reference installed in the imaging instrument. Together with corrections for magnification and anterior media absorption, this approach facilitates comparisons with serial images and images acquired within groups of patients. Here we provide a comprehensive summary of the principles and practice of qAF and we highlight recent efforts to elucidate retinal disease processes by combining qAF with multi-modal imaging.
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38
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Wang Y, Tran T, Firl K, Huang N, Yasin O, van Kuijk FJ, Montezuma SR. Quantitative fundus autofluorescence in smokers compared to non-smokers. Exp Eye Res 2019; 184:48-55. [DOI: 10.1016/j.exer.2019.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 03/19/2019] [Accepted: 04/04/2019] [Indexed: 01/29/2023]
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39
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Jeong SY, Gu X, Jeong KW. Photoactivation of N-retinylidene-N-retinylethanolamine compromises autophagy in retinal pigmented epithelial cells. Food Chem Toxicol 2019; 131:110555. [PMID: 31173818 DOI: 10.1016/j.fct.2019.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/30/2019] [Accepted: 06/01/2019] [Indexed: 01/05/2023]
Abstract
As a part of the aging process, N-retinylidene-N-retinylethanolamine (A2E) accumulates in the retina to activate autophagy in retinal pigmented epithelial cells. However, the effect of A2E photoactivation on autophagy, which is more clinically relevant, still remains unclear. Here, we investigated the effect of blue light (BL)-activated A2E on autophagy in human retinal pigmented epithelial cells, ARPE-19. A significant increase in LC3-II protein was observed when BL was irradiated on ARPE-19 cells containing A2E. The mammalian target of rapamycin (mTOR) pathway was examined to verify whether autophagy was activated, but no change in AKT, mTOR, and 4EBP phosphorylation was observed. Transcription factor EB (TFEB) target gene expression, which is another pathway involved in autophagy, was also not altered by A2E and BL. However, intracellular p62 protein levels were significantly increased, which represented the inhibition of autophagic flux. To investigate the mechanism of the suppressed autophagic flux, the lysosomal state was observed. After BL irradiation, lysosomal damage was induced in A2E-treated ARPE-19 cells, and this phenomenon was prevented by treatment with the antioxidant, N-acetylcysteine. Our results suggest that A2E photoactivation compromises autophagy in ARPE-19 cells and that reactive oxygen species (ROS) play an important role in this process.
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Affiliation(s)
- Seo Yeon Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Republic of Korea
| | - XiuHui Gu
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Republic of Korea
| | - Kwang Won Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Republic of Korea.
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40
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Zhao J, Ueda K, Riera M, Kim HJ, Sparrow JR. Bisretinoids mediate light sensitivity resulting in photoreceptor cell degeneration in mice lacking the receptor tyrosine kinase Mer. J Biol Chem 2018; 293:19400-19410. [PMID: 30352873 DOI: 10.1074/jbc.ra118.005949] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/19/2018] [Indexed: 12/13/2022] Open
Abstract
The receptor tyrosine kinase Mer is expressed by retinal pigment epithelial (RPE) cells and participates in photoreceptor outer-segment phagocytosis, a process enabling membrane renewal. Mutations in the gene encoding MERTK cause blinding retinitis pigmentosa in humans. Targeted Mertk disruption in mice causes defective RPE-mediated phagocytosis of the outer segments, leading to deposition of autofluorescent debris at the RPE-photoreceptor cell interface, followed by photoreceptor cell degeneration. Here, we show that retinaldehyde adducts (bisretinoid fluorophores) that form in photoreceptor outer segments occupy the unphagocytosed outer-segment debris that accumulates in Mertk -/- mice. Bisretinoids measured by HPLC were elevated in Mertk -/- mice compared with WT animals. Bisretinoids were also more abundant in albino Mertk -/- mice expressing leucine at position 450 of the isomerase RPE65 (Rpe65-Leu450) rather than the variant methionine (Rpe65-450Met) that yields lower bisretinoid levels. In Royal College of Surgeons rats having dysfunctional Mertk, bisretinoids were higher than in WT rats. Intensities of in vivo fundus autofluorescence were higher in Mertk -/- mice than in WT mice and peaked earlier in albino Mertk -/-/Rpe65-Leu450 mice than in albino Mertk -/-/Rpe65-450Met mice. Of note, the rate of photoreceptor cell degeneration was more rapid in albino Mertk -/- mice exposed to higher levels of intraocular light (albino versus pigmented mice) and in mice carrying Rpe65-Leu450 than in Rpe65-450Met mice, revealing a link between bisretinoid accumulation and light-mediated acceleration of photoreceptor cell degeneration. In conclusion, the light sensitivity of photoreceptor cell degeneration arising from Mertk deficiency is consistent with the known phototoxicity of bisretinoids.
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Affiliation(s)
- Jin Zhao
- From the Departments of Ophthalmology and
| | - Keiko Ueda
- From the Departments of Ophthalmology and
| | | | | | - Janet R Sparrow
- From the Departments of Ophthalmology and .,Pathology and Cell Biology, Columbia University Medical Center, New York, New York 10032
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41
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The clinical relevance of visualising the peripheral retina. Prog Retin Eye Res 2018; 68:83-109. [PMID: 30316018 DOI: 10.1016/j.preteyeres.2018.10.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 10/01/2018] [Accepted: 10/07/2018] [Indexed: 01/04/2023]
Abstract
Recent developments in imaging technologies now allow the documentation, qualitative and quantitative evaluation of peripheral retinal lesions. As wide field retinal imaging, capturing both the central and peripheral retina up to 200° eccentricity, is becoming readily available the question is: what is it that we gain by imaging the periphery? Based on accumulating evidence it is clear that findings in the periphery do not always associate to those observed in the posterior pole. However, the newly acquired information may provide useful clues to previously unrecognised disease features and may facilitate more accurate disease prognostication. In this review, we explore the anatomy and physiology of the peripheral retina, focusing on how it differs from the posterior pole, recount the history of peripheral retinal imaging, describe various peripheral retinal lesions and evaluate the overall relevance of peripheral retinal findings to different diseases.
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42
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Rowan S, Bejarano E, Taylor A. Mechanistic targeting of advanced glycation end-products in age-related diseases. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3631-3643. [PMID: 30279139 DOI: 10.1016/j.bbadis.2018.08.036] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/02/2018] [Accepted: 08/27/2018] [Indexed: 02/06/2023]
Abstract
Glycative stress, caused by the accumulation of cytotoxic and irreversibly-formed sugar-derived advanced glycation end-products (AGEs), contributes to morbidity associated with aging, age-related diseases, and metabolic diseases. In this review, we summarize pathways leading to formation of AGEs, largely from sugars and glycolytic intermediates, and discuss detoxification of AGE precursors, including the glyoxalase system and DJ-1/Park7 deglycase. Disease pathogenesis downstream of AGE accumulation can be cell autonomous due to aggregation of glycated proteins and impaired protein function, which occurs in ocular cataracts. Extracellular AGEs also activate RAGE signaling, leading to oxidative stress, inflammation, and leukostasis in diabetic complications such as diabetic retinopathy. Pharmaceutical agents have been tested in animal models and clinically to diminish glycative burden. We summarize existing strategies and point out several new directions to diminish glycative stress including: plant-derived polyphenols as AGE inhibitors and glyoxalase inducers; improved dietary patterns, particularly Mediterranean and low glycemic diets; and enhancing proteolytic capacities of the ubiquitin-proteasome and autophagy pathways that are involved in cellular clearing of AGEs.
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Affiliation(s)
- Sheldon Rowan
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington St, Boston, MA 02111, USA
| | - Eloy Bejarano
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington St, Boston, MA 02111, USA
| | - Allen Taylor
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington St, Boston, MA 02111, USA.
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43
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Spectral analysis of fundus autofluorescence pattern as a tool to detect early stages of degeneration in the retina and retinal pigment epithelium. Eye (Lond) 2018; 32:1440-1448. [PMID: 29786089 DOI: 10.1038/s41433-018-0109-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 02/27/2018] [Accepted: 03/30/2018] [Indexed: 01/14/2023] Open
Abstract
PURPOSE The aim of this work is the determination of quantitative diagnostic criteria based on the spectral characteristics of fundus autofluorescence to detect early stages of degeneration in the retina and retinal pigment epithelium (RPE). METHODS RPE cell suspension samples were obtained from the cadaver eyes with and without signs of age-related macular degeneration (AMD). Fluorescence analysis at an excitation wavelength of 488 nm was performed. The fluorescence lifetimes of lipofuscin-granule fluorophores were measured by counting time-correlated photon method. RESULTS Comparative analysis of fluorescence spectra of RPE cell suspensions from the cadaver eyes with and without signs of AMD showed a significant difference in fluorescence intensity at 530-580 nm in response to fluorescence excitation at 488 nm. It was notably higher in eyes with visual pathology than in normal eyes regardless of the age of the eye donor. Measurements of fluorescence lifetimes of lipofuscin fluorophores showed that the contribution of photooxidation and photodegradation products of bisretinoids to the total fluorescence at 530-580 nm of RPE cell suspensions was greater in eyes with visual pathology than in normal eyes. CONCLUSION Because photooxidation and photodegradation products of bisretinoids are markers of photodestructive processes, which can cause RPE cell death and initiate degenerative processes in the retina, quantitative determination of increases in these bisretinoid products in lipofuscin granules may be used to establish quantitative diagnostic criteria for degenerative processes in the retina and RPE.
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44
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Bisretinoid Photodegradation Is Likely Not a Good Thing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1074:395-401. [PMID: 29721969 DOI: 10.1007/978-3-319-75402-4_49] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Retinaldehyde adducts (bisretinoids) accumulate in retinal pigment epithelial (RPE) cells as lipofuscin. Bisretinoids are implicated in some inherited and age-related forms of macular degeneration that lead to the death of RPE cells and diminished vision. By comparing albino and black-eyed mice and by rearing mice in darkness and in cyclic light, evidence indicates that bisretinoid fluorophores undergo photodegradation in the eye (Ueda et al. Proc Natl Acad Sci 113:6904-6909, 2016). Given that the photodegradation products modify and impair cellular and extracellular molecules, these processes likely impart cumulative damage to retina.
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45
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Abstract
Cells are subject to metabolic sources of oxidizing species and to the need to regulate Fe, a redox-active metal. Retinal pigment epithelial (RPE) cells have to contend with an additional, unique source of oxidative stress: photooxidative insult from bisretinoids that accumulate as lipofuscin. Here we report that Fe can interact with bisretinoids in RPE to promote cell damage. These findings inform disease processes in both Fe-related and bisretinoid-associated retinal degeneration. The link between Fe and bisretinoid oxidation also highlights opportunities for repurposed and combination therapies. This could include visual cycle inhibitors as a treatment for maculopathy associated with elevated retinal Fe, and Fe chelation to aid in suppressing the damaging effects of bisretinoids in juvenile and age-related macular degeneration. Intracellular Fe plays a key role in redox active energy and electron transfer. We sought to understand how Fe levels impact the retina, given that retinal pigment epithelial (RPE) cells are also challenged by accumulations of vitamin A aldehyde adducts (bisretinoid lipofuscin) that photogenerate reactive oxygen species and photodecompose into damaging aldehyde- and dicarbonyl-bearing species. In mice treated with the Fe chelator deferiprone (DFP), intracellular Fe levels, as reflected in transferrin receptor mRNA expression, were reduced. DFP-treated albino Abca4−/− and agouti wild-type mice exhibited elevated bisretinoid levels as measured by high-performance liquid chromatography or noninvasively by quantitative fundus autofluorescence. Thinning of the outer nuclear layer, a parameter indicative of the loss of photoreceptor cell viability, was also reduced in DFP-treated albino Abca4−/−. In contrast to the effects of the Fe chelator, mice burdened with increased intracellular Fe in RPE due to deficiency in the Fe export proteins hephaestin and ceruloplasmin, presented with reduced bisretinoid levels. These findings indicate that intracellular Fe promotes bisretinoid oxidation and degradation. This interpretation was supported by experiments showing that DFP decreased the oxidative/degradation of the bisretinoid A2E in the presence of light and reduced cell death in cell-based experiments. Moreover, light-independent oxidation and degradation of A2E by Fenton chemistry products were evidenced by the consumption of A2E, release of dicarbonyls, and generation of oxidized A2E species in cell-free assays.
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46
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Peddada KV, Brown A, Verma V, Nebbioso M. Therapeutic potential of curcumin in major retinal pathologies. Int Ophthalmol 2018; 39:725-734. [DOI: 10.1007/s10792-018-0845-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/29/2018] [Indexed: 02/07/2023]
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47
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Yakovleva MA, Feldman TB, Arbukhanova PM, Borzenok SA, Kuzmin VA, Ostrovsky MA. The fluorescence lifetime of lipofuscin granule fluorophores contained in the retinal pigment epithelium cells from human cadaver eyes in normal state and in the case of visualized pathology. DOKL BIOCHEM BIOPHYS 2017; 474:239-243. [PMID: 28726093 DOI: 10.1134/s1607672917030231] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Indexed: 11/23/2022]
Abstract
A comparative analysis of fluorescence lifetime of lipofuscin granule fluorophores contained in the retinal pigment epithelium cells from human cadaver eyes in normal state and in the case of visualized pathology was carried out. Measurements of fluorescence lifetimes of bis-retinoids and their photooxidation and photodegradation products were carried out using the method of counting time-correlated photons. Comparative analysis showed that, in the case of visualized pathology, the contribution of photooxidation and photodegradation products of bis-retinoids to the total fluorescence of the retinal pigment epithelium cell suspension increases in comparison with the norm.
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Affiliation(s)
- M A Yakovleva
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia.
| | - T B Feldman
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia.,Biological Faculty, Moscow State University, Moscow, 119991, Russia
| | - P M Arbukhanova
- Fedorov Eye Microsurgery Research and Technology Complex, Ministry of Health of the Russian Federation, Moscow, 127486, Russia
| | - S A Borzenok
- Fedorov Eye Microsurgery Research and Technology Complex, Ministry of Health of the Russian Federation, Moscow, 127486, Russia
| | - V A Kuzmin
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
| | - M A Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia.,Biological Faculty, Moscow State University, Moscow, 119991, Russia
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48
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Wang Y, Kim HJ, Sparrow JR. Quercetin and cyanidin-3-glucoside protect against photooxidation and photodegradation of A2E in retinal pigment epithelial cells. Exp Eye Res 2017; 160:45-55. [PMID: 28461203 DOI: 10.1016/j.exer.2017.04.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 04/27/2017] [Indexed: 01/30/2023]
Abstract
A family of photoreactive retinaldehyde-derived molecules accumulate in retinal pigment epithelial cells with age; this accumulation is implicated in some retinal diseases. One of these compounds is the diretinal fluorophore A2E. Here we compared polyphenols for their ability to suppress the photooxidation and photodegradation of A2E. In cells that had accumulated A2E and were irradiated with short-wavelength light, quercetin, cyanidin-3-glucoside, ferulic acid and chlorogenic acid diminished cellular levels of reactive oxygen species, but only quercetin and cyanidin-3-glucoside promoted cell viability. By chromatographic quantitation, quercetin and cyanidin-3-glucoside reduced the consumption of A2E by photooxidation in both cell- and cell-free assays. With ultra-high performance liquid chromatography-mass spectrometry, quercetin and cyanidin-3-glucoside also inhibited the formation of photooxidized-A2E species. While photodegradation of A2E is known to result in the release of reactive carbonyls, we demonstrated that quercetin and cyanidin-3-glucoside decreased the formation of methylglyoxal adducts in the cells, and reduced the expression of mRNA encoding receptor for advanced glycation end products. These polyphenols also protected glutathione from reaction with photooxidized A2E. In rod outer segments incubated with all-trans-retinal to generate bisretinoid, followed by irradiation, quercetin and cyanidin-3-glucoside reduced release of the lipid peroxidation product 4-hydroxynonenal. In conclusion, quercetin and cyanidin-3-glucoside can guard against photooxidative processes in retina.
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Affiliation(s)
- Yong Wang
- Department of Ophthalmology, Columbia University Medical Center, New York, NY 10032, United States
| | - Hye Jin Kim
- Department of Ophthalmology, Columbia University Medical Center, New York, NY 10032, United States
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, NY 10032, United States; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, United States.
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49
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Lei L, Tzekov R, Li H, McDowell JH, Gao G, Smith WC, Tang S, Kaushal S. Inhibition or Stimulation of Autophagy Affects Early Formation of Lipofuscin-Like Autofluorescence in the Retinal Pigment Epithelium Cell. Int J Mol Sci 2017; 18:ijms18040728. [PMID: 28353645 PMCID: PMC5412314 DOI: 10.3390/ijms18040728] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 12/22/2022] Open
Abstract
The accumulation of lipofuscin in the retinal pigment epithelium (RPE) is dependent on the effectiveness of photoreceptor outer segment material degradation. This study explored the role of autophagy in the fate of RPE lipofuscin degradation. After seven days of feeding with either native or modified rod outer segments, ARPE-19 cells were treated with enhancers or inhibitors of autophagy and the autofluorescence was detected by fluorescence-activated cell sorting. Supplementation with different types of rod outer segments increased lipofuscin-like autofluorescence (LLAF) after the inhibition of autophagy, while the induction of autophagy (e.g., application of rapamycin) decreased LLAF. The effects of autophagy induction were further confirmed by Western blotting, which showed the conversion of LC3-I to LC3-II, and by immunofluorescence microscopy, which detected the lysosomal activity of the autophagy inducers. We also monitored LLAF after the application of several autophagy inhibitors by RNA-interference and confocal microscopy. The results showed that, in general, the inhibition of the autophagy-related proteins resulted in an increase in LLAF when cells were fed with rod outer segments, which further confirms the effect of autophagy in the fate of RPE lipofuscin degradation. These results emphasize the complex role of autophagy in modulating RPE autofluorescence and confirm the possibility of the pharmacological clearance of RPE lipofuscin by small molecules.
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Affiliation(s)
- Lei Lei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, No.54 South Xianlie Road, Guangzhou 510060, China.
- Department of Ophthalmology, University of Massachusetts Medical School, 381 Plantation Street, Worcester, MA 01605, USA.
| | - Radouil Tzekov
- Department of Ophthalmology, University of Massachusetts Medical School, 381 Plantation Street, Worcester, MA 01605, USA.
- Department of Ophthalmology, University of South Florida, 13127 USF Magnolia Drive, Tampa, FL 33612, USA.
- The Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA.
| | - Huapeng Li
- Gene Therapy Center, University of Massachusetts Medical School, 381 Plantation Street, Worcester, MA 01605, USA.
| | - J Hugh McDowell
- The Department of Ophthalmology, University of Florida Health Science Center, 1600 SW Archer Road, Gainesville, FL 32610, USA.
| | - Guangping Gao
- Gene Therapy Center, University of Massachusetts Medical School, 381 Plantation Street, Worcester, MA 01605, USA.
| | - W Clay Smith
- The Department of Ophthalmology, University of Florida Health Science Center, 1600 SW Archer Road, Gainesville, FL 32610, USA.
| | - Shibo Tang
- Aier School of Ophthalmology, Central South University, Floor 4, New Century Building, 198# Furong Middle Road, Changsha 410015, China.
| | - Shalesh Kaushal
- Department of Ophthalmology, University of Massachusetts Medical School, 381 Plantation Street, Worcester, MA 01605, USA.
- VRMI, 6205 NW 81st Drive, Gainesville, FL 32653, USA.
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50
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Fontaine V, Monteiro E, Brazhnikova E, Lesage L, Balducci C, Guibout L, Feraille L, Elena PP, Sahel JA, Veillet S, Lafont R. Norbixin Protects Retinal Pigmented Epithelium Cells and Photoreceptors against A2E-Mediated Phototoxicity In Vitro and In Vivo. PLoS One 2016; 11:e0167793. [PMID: 27992460 PMCID: PMC5161507 DOI: 10.1371/journal.pone.0167793] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 11/20/2016] [Indexed: 12/31/2022] Open
Abstract
The accumulation of N-retinylidene-N-retinylethanolamine (A2E, a toxic by-product of the visual pigment cycle) in the retinal pigment epithelium (RPE) is a major cause of visual impairment in the elderly. Photooxidation of A2E results in retinal pigment epithelium degeneration followed by that of associated photoreceptors. Present treatments rely on nutrient supplementation with antioxidants. 9’-cis-Norbixin (a natural diapocarotenoid, 97% purity) was prepared from Bixa orellana seeds. It was first evaluated in primary cultures of porcine retinal pigment epithelium cells challenged with A2E and illuminated with blue light, and it provided an improved photo-protection as compared with lutein or zeaxanthin. In Abca4-/-Rdh8-/- mice (a model of dry AMD), intravitreally-injected norbixin maintained the electroretinogram and protected photoreceptors against light damage. In a standard rat blue-light model of photodamage, norbixin was at least equally as active as phenyl-N-tert-butylnitrone, a free radical spin-trap. Chronic experiments performed with Abca4-/-Rdh8-/- mice treated orally for 3 months with norbixin showed a reduced A2E accumulation in the retina. Norbixin appears promising for developing an oral treatment of macular degeneration. A drug candidate (BIO201) with 9’-cis-norbixin as the active principle ingredient is under development, and its potential will be assessed in a forthcoming clinical trial.
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Affiliation(s)
- Valérie Fontaine
- Sorbonne Universités, UPMC Univ Paris, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, Paris, France
- * E-mail:
| | - Elodie Monteiro
- Sorbonne Universités, UPMC Univ Paris, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, Paris, France
| | - Elena Brazhnikova
- Sorbonne Universités, UPMC Univ Paris, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, Paris, France
| | - Laëtitia Lesage
- Sorbonne Universités, UPMC Univ Paris, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, Paris, France
| | - Christine Balducci
- Biophytis, Parc BIOCITECH, 102 Avenue Gaston Roussel, Romainville, France
| | - Louis Guibout
- Biophytis, Parc BIOCITECH, 102 Avenue Gaston Roussel, Romainville, France
| | | | | | - José-Alain Sahel
- Sorbonne Universités, UPMC Univ Paris, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, Paris, France
| | - Stanislas Veillet
- Biophytis, Parc BIOCITECH, 102 Avenue Gaston Roussel, Romainville, France
| | - René Lafont
- Biophytis, Parc BIOCITECH, 102 Avenue Gaston Roussel, Romainville, France
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