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Serejnikova NB, Trofimova NN, Yakovleva MA, Dontsov AE, Zak PP, Ostrovsky MA. Blue Light-Induced Accelerated Formation of Melanolipofuscin-Like Organelles in Japanese Quail RPE Cells: An Electron Microscopic Study. Invest Ophthalmol Vis Sci 2024; 65:31. [PMID: 39297806 PMCID: PMC11421679 DOI: 10.1167/iovs.65.11.31] [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: 05/02/2024] [Accepted: 09/02/2024] [Indexed: 09/26/2024] Open
Abstract
Purpose The retinal pigment epithelium (RPE) is a monolayer of epithelial cells essential for photoreceptor function and viability. Quail Coturnix japonica is a convenient experimental animal model for the study of age and pathological retina processes to an accelerated time regime. The three main types of pigment granules present in the RPE are melanin-containing melanosomes, lipofuscin-containing lipofuscin granules, and mixed melanolipofuscin granules containing both melanin and lipofuscin. The purpose of this work was to study the process of melanolipofuscinogenesis during aging and under light exposure. Methods We examined melanolipofuscin granules in "macular" areas, the area of the retina containing oxycarotenoids, as a function of the macula in humans, of the quail retina by transmission electron microscopy in young, middle-aged, and old birds, and in middle-aged birds irradiated with blue LED light (450 nm, 4 J/cm2). Results It has been shown that during photo-oxidative stress caused by the action of blue light on the quail eye, active fusion of melanosomes and lipofuscin granules occurs with formation of various types, including giant, mixed melanolipofuscin-like granules. Increased accumulation of melanolipofuscin-like granules was also observed in non-irradiated old birds. Conclusions It is assumed that the decrease in the number of melanosomes in the RPE during aging and photo-oxidative stress is associated with their fusion with lipofuscin granules and subsequent degradation of melanin by reactive oxygen species formed in melanolipofuscin-like granules. The disappearance of melanin deprives the RPE cells of light-filtering and antioxidant protection, and significantly increases the risk of their oxidative stress.
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Affiliation(s)
| | - Natalia N. Trofimova
- N. N. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - Marina A. Yakovleva
- N. N. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - Alexander E. Dontsov
- N. N. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - Pavel P. Zak
- N. N. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - Mikhail A. Ostrovsky
- N. N. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
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Andreazzoli M, Longoni B, Angeloni D, Demontis GC. Retinoid Synthesis Regulation by Retinal Cells in Health and Disease. Cells 2024; 13:871. [PMID: 38786093 PMCID: PMC11120330 DOI: 10.3390/cells13100871] [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: 02/07/2024] [Revised: 05/13/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Vision starts in retinal photoreceptors when specialized proteins (opsins) sense photons via their covalently bonded vitamin A derivative 11cis retinaldehyde (11cis-RAL). The reaction of non-enzymatic aldehydes with amino groups lacks specificity, and the reaction products may trigger cell damage. However, the reduced synthesis of 11cis-RAL results in photoreceptor demise and suggests the need for careful control over 11cis-RAL handling by retinal cells. This perspective focuses on retinoid(s) synthesis, their control in the adult retina, and their role during retina development. It also explores the potential importance of 9cis vitamin A derivatives in regulating retinoid synthesis and their impact on photoreceptor development and survival. Additionally, recent advancements suggesting the pivotal nature of retinoid synthesis regulation for cone cell viability are discussed.
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Affiliation(s)
| | - Biancamaria Longoni
- Department of Translational Medicine and New Technologies in Medicine, University of Pisa, 56126 Pisa, Italy
| | - Debora Angeloni
- The Institute of Biorobotics, Scuola Superiore Sant’Anna, 56127 Pisa, Italy
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3
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Delanghe JR, Diana Di Mavungu J, Beerens K, Himpe J, Bostan N, Speeckaert MM, Vrielinck H, Vral A, Van Den Broeke C, Huizing M, Van Aken E. Fructosyl Amino Oxidase as a Therapeutic Enzyme in Age-Related Macular Degeneration. Int J Mol Sci 2024; 25:4779. [PMID: 38732004 PMCID: PMC11083825 DOI: 10.3390/ijms25094779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/14/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024] Open
Abstract
Age-related macular degeneration (AMD) is an age-related disorder that is a global public health problem. The non-enzymatic Maillard reaction results in the formation of advanced glycation end products (AGEs). Accumulation of AGEs in drusen plays a key role in AMD. AGE-reducing drugs may contribute to the prevention and treatment of AGE-related disease. Fructosamine oxidase (FAOD) acts on fructosyl lysine and fructosyl valine. Based upon the published results of fructosamine 3-kinase (FN3K) and FAOD obtained in cataract and presbyopia, we studied ex vivo FAOD treatment as a non-invasive AMD therapy. On glycolaldehyde-treated porcine retinas, FAOD significantly reduced AGE autofluorescence (p = 0.001). FAOD treatment results in a breakdown of AGEs, as evidenced using UV fluorescence, near-infrared microspectroscopy on stained tissue sections of human retina, and gel permeation chromatography. Drusen are accumulations of AGEs that build up between Bruch's membrane and the retinal pigment epithelium. On microscopy slides of human retina affected by AMD, a significant reduction in drusen surface to 45 ± 21% was observed following FAOD treatment. Enzymatic digestion followed by mass spectrometry of fructose- and glucose-based AGEs (produced in vitro) revealed a broader spectrum of substrates for FAOD, as compared to FN3K, including the following: fructosyllysine, carboxymethyllysine, carboxyethyllysine, and imidazolone. In contrast to FN3K digestion, agmatine (4-aminobutyl-guanidine) was formed following FAOD treatment in vitro. The present study highlights the therapeutic potential of FAOD in AMD by repairing glycation-induced damage.
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Affiliation(s)
- Joris R. Delanghe
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium;
| | - Jose Diana Di Mavungu
- Department of Green Chemistry and Technology, MSsmall Expertise Centre, Mass Spectrometry Analysis of Small Organic Molecules, Ghent University, 9000 Ghent, Belgium;
| | - Koen Beerens
- Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium;
| | - Jonas Himpe
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium;
| | - Nezahat Bostan
- Antwerp Biobank, Antwerp University Hospital, 2650 Antwerp, Belgium; (N.B.); (M.H.)
| | - Marijn M. Speeckaert
- Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium;
| | - Henk Vrielinck
- Department of Solid State Sciences, Ghent University, 9000 Ghent, Belgium;
| | - Anne Vral
- Department of Human Structure and Repair, Ghent University, 9000 Ghent, Belgium;
| | | | - Manon Huizing
- Antwerp Biobank, Antwerp University Hospital, 2650 Antwerp, Belgium; (N.B.); (M.H.)
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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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5
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Zhao J, Kim HJ, Montenegro D, Dunaief JL, Sparrow JR. Iron overload and chelation modulates bisretinoid levels in the retina. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1305864. [PMID: 38983013 PMCID: PMC11182296 DOI: 10.3389/fopht.2023.1305864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 12/07/2023] [Indexed: 07/11/2024]
Abstract
Aim Iron dysregulation in conjunction with other disease processes may exacerbate retinal degeneration. We employed models of iron overload and iron chelation to explore the interactions between iron-catalyzed oxidation and photoreactive bisretinoid lipofuscin. Methods The mice were injected intravitreally with ferric ammonium citrate (FAC) or were treated using the iron chelator deferiprone (DFP) from birth to 2 months of age. Short-wavelength fundus autofluorescence (SW-AF) and spectral-domain optical coherence tomography (SD-OCT) scans were acquired. The bisretinoid levels were quantified using ultra performance liquid chromatography (UPLC) and in vivo through quantitative fundus autofluorescence (qAF). In histologic sections, the photoreceptor cell viability was assessed by measuring the thickness of the outer nuclear layer (ONL). Results The levels of bisretinoids, all-trans-retinal dimers, and A2PE were significantly increased in the FAC-injected eyes of C57BL/6J mice. Seven days after FAC injection, hyperautofluorescent foci were visible in fundus autofluorescence (488 nm) images, and in SD-OCT scans, aberrant hyperreflectivity was present in the outer retina and ONL thinning was observed. In FAC-injected Abca4-/- mice with pronounced RPE bisretinoid lipofuscin accumulation, the hyperautofluorescent puncta were more abundant than in the wild-type mice, and the extent of ONL thinning was greater. Conversely, the intravitreal injection of FAC in Mertk-/- mice led to a more modest increase in A2PE after 2 days. In contrast to the effect of iron accumulation, chelation with DFP resulted in significantly increased levels of A2E and A2-GPE and qAF due to the reduced iron-catalyzed oxidation of bisretinoids. In Mertk-/- mice, the A2E level was significantly lower and the ONL area was smaller than in DFP-treated mice. DFP chelation did not impair the visual cycle in BALB/cJ mice. Conclusion Iron accumulation was associated with progressive impairment in photoreceptor cells that was associated with the increased formation of a bisretinoid species known to form in photoreceptor outer segments as a precursor to A2E. Additionally, disease features such as the development of hyperautofluorescence puncta in fundus AF images, hyperreflectivity in the outer retina of SD-OCT scans, and ONL thinning were more pronounced when iron was delivered to Abca4-/- mice with a greater propensity for bisretinoid formation. Higher bisretinoid levels and enhanced qAF are indicative of lesser bisretinoid loss due to oxidation.
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Affiliation(s)
- Jin Zhao
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Hye Jin Kim
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Diego Montenegro
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Josh L Dunaief
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Janet R Sparrow
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
- Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
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6
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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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7
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Perron A, Mandal S, Chuba TN, Mao D, Singh VP, Noda N, Tan R, Vu HT, Abo M, Uesugi M. Small-Molecule Drug Repurposing for Counteracting Phototoxic A2E Aggregation. ACS Chem Biol 2023; 18:2170-2175. [PMID: 37708070 DOI: 10.1021/acschembio.3c00339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
Despite the well-established role of oxidative stress in the pathogenesis of age-related macular degeneration (AMD), the mechanism underlying phototoxicity remains unclear. Herein, we used a drug repurposing approach to isolate an FDA-approved drug that blocks the aggregation of the photoinducible major fluorophore of lipofuscin, the bis-retinoid N-retinylidene-N-retinylethanolamine (A2E). Our fluorescence-based screening combined with dynamic light scattering (DLS) analysis led to the identification of entacapone as a potent inhibitor of A2E fluorescence and aggregation. The entacapone-mediated inhibition of A2E aggregation blocks its photodegradation and offers photoprotection in A2E-loaded retinal pigment epithelial (RPE) cells exposed to blue light. In-depth mechanistic analysis suggests that entacapone prevents the conversion of toxic aggregates by redirecting A2E into off-pathway oligomers. These findings provide evidence that aggregation contributes to the phototoxicity of A2E.
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Affiliation(s)
- Amelie Perron
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Sathi Mandal
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Thiago Negrão Chuba
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Kyoto 606-850, Japan
| | - Di Mao
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Vaibhav Pal Singh
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Naotaka Noda
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Russell Tan
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Hue Thi Vu
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Masahiro Abo
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Motonari Uesugi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Uji, Kyoto 611-0011, Japan
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8
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Zhang KR, Jankowski CSR, Marshall R, Nair R, Más Gómez N, Alnemri A, Liu Y, Erler E, Ferrante J, Song Y, Bell BA, Baumann BH, Sterling J, Anderson B, Foshe S, Roof J, Fazelinia H, Spruce LA, Chuang JZ, Sung CH, Dhingra A, Boesze-Battaglia K, Chavali VRM, Rabinowitz JD, Mitchell CH, Dunaief JL. Oxidative stress induces lysosomal membrane permeabilization and ceramide accumulation in retinal pigment epithelial cells. Dis Model Mech 2023; 16:dmm050066. [PMID: 37401371 PMCID: PMC10399446 DOI: 10.1242/dmm.050066] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 06/23/2023] [Indexed: 07/05/2023] Open
Abstract
Oxidative stress has been implicated in the pathogenesis of age-related macular degeneration, the leading cause of blindness in older adults, with retinal pigment epithelium (RPE) cells playing a key role. To better understand the cytotoxic mechanisms underlying oxidative stress, we used cell culture and mouse models of iron overload, as iron can catalyze reactive oxygen species formation in the RPE. Iron-loading of cultured induced pluripotent stem cell-derived RPE cells increased lysosomal abundance, impaired proteolysis and reduced the activity of a subset of lysosomal enzymes, including lysosomal acid lipase (LIPA) and acid sphingomyelinase (SMPD1). In a liver-specific Hepc (Hamp) knockout murine model of systemic iron overload, RPE cells accumulated lipid peroxidation adducts and lysosomes, developed progressive hypertrophy and underwent cell death. Proteomic and lipidomic analyses revealed accumulation of lysosomal proteins, ceramide biosynthetic enzymes and ceramides. The proteolytic enzyme cathepsin D (CTSD) had impaired maturation. A large proportion of lysosomes were galectin-3 (Lgals3) positive, suggesting cytotoxic lysosomal membrane permeabilization. Collectively, these results demonstrate that iron overload induces lysosomal accumulation and impairs lysosomal function, likely due to iron-induced lipid peroxides that can inhibit lysosomal enzymes.
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Affiliation(s)
- Kevin R. Zhang
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Connor S. R. Jankowski
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Rayna Marshall
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rohini Nair
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Néstor Más Gómez
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ahab Alnemri
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yingrui Liu
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elizabeth Erler
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Julia Ferrante
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brent A. Bell
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bailey H. Baumann
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jacob Sterling
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brandon Anderson
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sierra Foshe
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jennifer Roof
- CHOP-PENN Proteomics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Hossein Fazelinia
- CHOP-PENN Proteomics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Lynn A. Spruce
- CHOP-PENN Proteomics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Jen-Zen Chuang
- Department of Ophthalmology, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Ching-Hwa Sung
- Department of Ophthalmology, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Anuradha Dhingra
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Venkata R. M. Chavali
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joshua D. Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Claire H. Mitchell
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joshua L. Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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Sekar P, Hsiao G, Hsu SH, Huang DY, Lin WW, Chan CM. Metformin inhibits methylglyoxal-induced retinal pigment epithelial cell death and retinopathy via AMPK-dependent mechanisms: Reversing mitochondrial dysfunction and upregulating glyoxalase 1. Redox Biol 2023; 64:102786. [PMID: 37348156 PMCID: PMC10363482 DOI: 10.1016/j.redox.2023.102786] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 06/09/2023] [Accepted: 06/14/2023] [Indexed: 06/24/2023] Open
Abstract
Diabetic retinopathy (DR) is a major cause of blindness in adult, and the accumulation of advanced glycation end products (AGEs) is a major pathologic event in DR. Methylglyoxal (MGO), a highly reactive dicarbonyl compound, is a precursor of AGEs. Although the therapeutic potential of metformin for retinopathy disorders has recently been elucidated, possibly through AMPK activation, it remains unknown how metformin directly affects the MGO-induced stress response in retinal pigment epithelial cells. Therefore, in this study, we compared the effects of metformin and the AMPK activator A769662 on MGO-induced DR in mice, as well as evaluated cytotoxicity, mitochondrial dynamic changes and dysfunction in ARPE-19 cells. We found MGO can induce mitochondrial ROS production and mitochondrial membrane potential loss, but reduce cytosolic ROS level in ARPE-19 cells. Although these effects of MGO can be reversed by both metformin and A769662, we demonstrated that reduction of mitochondrial ROS production rather than restoration of cytosolic ROS level contributes to cell protective effects of metformin and A769662. Moreover, MGO inhibits AMPK activity, reduces LC3II accumulation, and suppresses protein and gene expressions of MFN1, PGC-1α and TFAM, leading to mitochondrial fission, inhibition of mitochondrial biogenesis and autophagy. In contrast, these events of MGO were reversed by metformin in an AMPK-dependent manner as evidenced by the effects of compound C and AMPK silencing. In addition, we observed an AMPK-dependent upregulation of glyoxalase 1, a ubiquitous cellular enzyme that participates in the detoxification of MGO. In intravitreal drug-treated mice, we found that AMPK activators can reverse the MGO-induced cotton wool spots, macular edema and retinal damage. Functional, histological and optical coherence tomography analysis support the protective actions of both agents against MGO-elicited retinal damage. Metformin and A769662 via AMPK activation exert a strong protection against MGO-induced retinal pigment epithelial cell death and retinopathy. Therefore, metformin and AMPK activator can be therapeutic agents for DR.
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Affiliation(s)
- Ponarulselvam Sekar
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | - George Hsiao
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | - Shu-Hao Hsu
- Medical Research Center, Cardinal Tien Hospital, New Taipei City, Taiwan
| | - Duen-Yi Huang
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wan-Wan Lin
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan; Department and Graduate Institute of Pharmacology, National Defense Medical Center, Taipei, Taiwan.
| | - Chi-Ming Chan
- Department of Ophthalmology, Cardinal Tien Hospital, New Taipei City, Taiwan; School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan.
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10
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Radzin S, Wiśniewska-Becker A, Markiewicz M, Bętkowski S, Furso J, Waresiak J, Grolik J, Sarna T, Pawlak AM. Structural Impact of Selected Retinoids on Model Photoreceptor Membranes. MEMBRANES 2023; 13:575. [PMID: 37367779 DOI: 10.3390/membranes13060575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/07/2023] [Accepted: 05/27/2023] [Indexed: 06/28/2023]
Abstract
Photoreceptor membranes have a unique lipid composition. They contain a high level of polyunsaturated fatty acids including the most unsaturated fatty acid in nature, docosahexaenoic acid (22:6), and are enriched in phosphatidylethanolamines. The phospholipid composition and cholesterol content of the subcellular components of photoreceptor outer segments enables to divide photoreceptor membranes into three types: plasma membranes, young disc membranes, and old disc membranes. A high degree of lipid unsaturation, extended exposure to intensive irradiation, and high respiratory demands make these membranes sensitive to oxidative stress and lipid peroxidation. Moreover, all-trans retinal (AtRAL), which is a photoreactive product of visual pigment bleaching, accumulates transiently inside these membranes, where its concentration may reach a phototoxic level. An elevated concentration of AtRAL leads to accelerated formation and accumulation of bisretinoid condensation products such as A2E or AtRAL dimers. However, a possible structural impact of these retinoids on the photoreceptor-membrane properties has not yet been studied. In this work we focused just on this aspect. The changes induced by retinoids, although noticeable, seem not to be significant enough to be physiologically relevant. This is, however, an positive conclusion because it can be assumed that accumulation of AtRAL in photoreceptor membranes will not affect the transduction of visual signals and will not disturb the interaction of proteins engaged in this process.
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Affiliation(s)
- Szymon Radzin
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
| | - Anna Wiśniewska-Becker
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
| | - Michał Markiewicz
- Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics, Jagiellonian University, 30-387 Krakow, Poland
| | - Sebastian Bętkowski
- Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics, Jagiellonian University, 30-387 Krakow, Poland
| | - Justyna Furso
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
| | - Joanna Waresiak
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
| | - Jarosław Grolik
- Department of Organic Chemistry, Faculty of Chemistry, Jagiellonian University, 30-387 Krakow, Poland
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
| | - Anna M Pawlak
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
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11
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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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12
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Concentrations of N 6-Carboxymethyllysine (CML), N 6-Carboxyethyllysine (CEL), and Soluble Receptor for Advanced Glycation End-Products (sRAGE) Are Increased in Psoriatic Patients. Biomolecules 2022; 12:biom12121870. [PMID: 36551298 PMCID: PMC9775373 DOI: 10.3390/biom12121870] [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: 11/07/2022] [Revised: 12/03/2022] [Accepted: 12/12/2022] [Indexed: 12/15/2022] Open
Abstract
Psoriasis is a chronic, recurrent, and often severe skin disease which is frequently associated with metabolic disorders and increased risk of cardiovascular complications. One of the postulated links is an intensified process of advanced protein glycation and/or glycoxidation. Therefore, the aim of the study was to assess concentrations of N6-carboxymethyllysine (CML), N6-carboxyethyllysine (CEL), and soluble form of receptor for advanced glycation end-products (sRAGE) in psoriasis patients at different phases of the disease activity, in comparison to healthy individuals. The study material consisted of sera from psoriasis patients in active phase, in the remission phase, and healthy controls. Concentrations of CML, CEL, and sRAGE were determined using ELISA technique. In the patients with psoriasis (in both phases of the disease), concentrations of CML, CEL and sRAGE were significantly higher than in healthy individuals but they did not correlate with psoriasis area severity index (PASI) values. The remission of the disease was followed by a significant decrease in CML, CEL, and sRAGE concentrations when compared to active patients; however, these concentrations were still significantly higher than in the controls. Our data suggest that psoriasis is accompanied by an intense glycoxidation process and that high sRAGE levels seem to reflect permanent RAGE overstimulation.
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13
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Askari S, Azizi F, Javadpour P, Karimi N, Ghasemi R. Endoplasmic reticulum stress as an underlying factor in leading causes of blindness and potential therapeutic effects of 4-phenylbutyric acid: from bench to bedside. EXPERT REVIEW OF OPHTHALMOLOGY 2022. [DOI: 10.1080/17469899.2022.2145945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Sahar Askari
- Neuroscience Research center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Azizi
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Pegah Javadpour
- Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nasser Karimi
- Eye and Skull Base Research Centers, The Five Senses Institute, Iran University of Medical Sciences, Tehran, Iran5Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rasoul Ghasemi
- Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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14
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Perveen I, Johnson BA, Gowda V, Foley B, Okezie S, O’Brien M, Watanabe CMH. Catabolism of the Lipofuscin Cycloretinal by MsP1. Biochemistry 2022; 61:2560-2567. [DOI: 10.1021/acs.biochem.2c00413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Irum Perveen
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Brett A. Johnson
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Vishruth Gowda
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Brendan Foley
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Stephanie Okezie
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Mackenzie O’Brien
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Coran M. H. Watanabe
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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15
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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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16
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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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17
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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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18
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Lee IS, Kim CS, Kim J, Jo K, Hyun SW, Zhang H, Noh M, Kwon YG, Kim M, Kim JS. Extract of Moutan radicis cortex and Cinnamomi ramulus ameliorates laser-induced choroidal neovascularization in Brown-Norway rats. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 94:153794. [PMID: 34775362 DOI: 10.1016/j.phymed.2021.153794] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 05/17/2021] [Accepted: 10/03/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Moutan radicis cortex (MRC) and Cinnamomi ramulus (CR) are commonly used in eastern Asian traditional medicine to treat various diseases including cerebrovascular and cardiovascular, and have wide spectrum of pharmacological activities. However, the effect against laser-induced choroidal neovascularization (CNV) of extract of MRC and CR (1:1) (MRCCR) has not yet been studied. PURPOSE Our aim was to investigate the inhibitory effect of MRCCR on pathological CNV in laser-treated Brown-Norway (BN) rats. METHODS MRCCR (60, 90 mg/kg) was orally administered twice per day for 15 days from the day of CNV formation in laser-treated BN rats. Effects of MRCCR or its constituents on cell migration, tube formation, hyperpermeability and phosphorylation of FAK/p38 MAPK were confirmed in humane retinal microvascular endothelial cells or human retinal pigment epithelial cells. RESULTS MRCCR significantly reduced the CNV lesions areas and the extent of fluorescein leakage. MRCCR and its constituents such as ellagic acid, paeonol or gallic acid decreased cell migration, tube formation or hyperpermeability. MRCCR inhibited the phosphorylation of FAK and p38 MAPK. CONCLUSION Combining the oral MRCCR and intravitreal injection of anti-VEGF medicine may result in a more potent therapeutic effect and consequently bring the reduction in eye injection numbers for patients with wet AMD.
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Affiliation(s)
- Ik Soo Lee
- Herbal Medicine Research Division, Korea Institute of Oriental Medicine, Daejeon 34054, Republic of Korea
| | - Chan-Sik Kim
- Clinical Medicine Division, Korea Institute of Oriental Medicine, Daejeon 34054, Republic of Korea
| | - Junghyun Kim
- Department of Oral pathology, School of Dentistry, Jeonbuk National University, Jeonju 54896, Republic of Korea
| | - Kyuhyung Jo
- Herbal Medicine Research Division, Korea Institute of Oriental Medicine, Daejeon 34054, Republic of Korea
| | - Soo Wang Hyun
- Herbal Medicine Research Division, Korea Institute of Oriental Medicine, Daejeon 34054, Republic of Korea; Practical Research Division, Honam National Institute of Biological Resources, Mokpo, 58762, Republic of Korea
| | | | - MinYoung Noh
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120749, Republic of Korea
| | - Young-Guen Kwon
- Curacle Co. Ltd, Seongnam 13449, Republic of Korea; Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120749, Republic of Korea
| | - MyungHwa Kim
- Curacle Co. Ltd, Seongnam 13449, Republic of Korea
| | - Jin Sook Kim
- Herbal Medicine Research Division, Korea Institute of Oriental Medicine, Daejeon 34054, Republic of Korea.
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19
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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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20
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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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21
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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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22
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Tang SS, Xing SY, Zhang XJ, Ren XQ, Hong H, Long Y. Neuroprotective effects of novel compound Tozan on cognition, neurogenesis and apoptosis in diabetes. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1471. [PMID: 34734023 PMCID: PMC8506716 DOI: 10.21037/atm-21-4439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/10/2021] [Indexed: 11/06/2022]
Abstract
Background Cognitive impairment is a serious complication of diabetes that manifests as an impairment of spatial memory and learning ability. Its pathogenesis is unclear, and effective therapeutic drugs are very limited. Our group designed and synthesized a novel compound named 3-p-tolyl-9H-xanthen-9-one (Tozan). In this study, we sought to investigate the effects and mechanism of Tozan on diabetic cognitive impairment. Methods Methylglyoxal (MG)-induced SH-SY5Y cells and streptozotocin (STZ)-induced type 1 diabetic mice were treated with Tozan. Methyl thiazolul tetrazolium (MTT) and lactate dehydrogenase (LDH) were used to test cytotoxicity. Morris water maze (MWM) and Y-maze tests were used to evaluate cognitive function. Immunofluorescence and western blot analyses were used to evaluate neurogenesis, apoptosis, and signal transduction pathway-related proteins. In addition, Lentivirus (LV)-estrogen receptor beta (ERβ)-ribonucleic acid interference (RNAi) was used to knockdown the ERβ gene in SH-SY5Y cells. Results We found that Tozan ameliorated MG-induced cytotoxicity in SH-SY5Y cells, improved cognitive dysfunction in STZ-induced type 1 diabetic mice, increased neurogenesis, and prevented apoptotic responses in vitro and in vivo. Importantly, Tozan (2, 4, and 8 mg/kg) mediated phosphatidylinositol-3-kinase and protein kinase B cAMP-response element binding protein (PI3K/Akt-CREB) signaling by activating membrane ERβ, and a high dose of Tozan (8 mg/kg) mediated CREB signaling by activating nuclear ERβ in the hippocampus. Notably, Tozan did not have an anti-apoptosis and regeneration protective role in ERβ gene knockdown cells. Conclusions Our study demonstrates Tozan’s contributions to and role in cognition, neurogenesis, and apoptosis in diabetes, and lays an experimental foundation for the development of new anti-diabetic cognitive impairment drugs.
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Affiliation(s)
- Su-Su Tang
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Shu-Yun Xing
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Xue-Jiao Zhang
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Xiao-Qian Ren
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Hao Hong
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Yan Long
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
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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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Chen L, Messinger JD, Ferrara D, Freund KB, Curcio CA. Stages of Drusen-Associated Atrophy in Age-Related Macular Degeneration Visible via Histologically Validated Fundus Autofluorescence. Ophthalmol Retina 2021; 5:730-742. [PMID: 33217617 PMCID: PMC9749404 DOI: 10.1016/j.oret.2020.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/29/2020] [Accepted: 11/12/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE To determine histologic correlates for stages of drusen-associated atrophy observed with fundus autofluorescence (FAF) and color fundus photography (CFP), of eyes with advanced age-related macular degeneration (AMD). DESIGN Case study and clinicopathologic correlation. PARTICIPANT A white woman with AMD findings of inactive subretinal fibrosis (right eye) and untreated nonexudative type 1 macular neovascularization (left eye) was followed for 9 years before death at 90 years of age. METHODS Eyes preserved 6.25 hours after death were postfixed in osmium tannic acid paraphenylenediamine and were prepared for submicrometer epoxy resin sections (115 and 90 from the right and left eye, respectively), with 19 aligned to clinical B-scans. Drusen visible by CFP at the last visit were assigned to 4 stages of FAF: stage 1, isoautofluorescence; stage 2, mildly uniform hyperautofluorescence; stage 3, a ring of hyperautofluorescence around a center of the hypoautofluorescence; and stage 4, uniform hypoautofluorescence. MAIN OUTCOME MEASURES Light microscopic morphologic features at known FAF stages, including druse size, druse contents, and changes in overlying retinal pigment epithelium (RPE), photoreceptors, and external limiting membrane (ELM). RESULTS Histologic examination of 166 drusen demonstrated that stage 1 isoautofluorescent drusen were visible on CFP. Hyperautofluorescence in stage 2 corresponded to short photoreceptors and complete coverage by RPE. Hypoautofluorescence in stages 3 and 4 corresponded to different extents of RPE atrophy (RPE gap and no RPE, respectively). Of stage 4 drusen, 67% showed no outer nuclear layer (ONL) and an undetectable ELM. Stage 4 included a high proportion of refractile drusen (82%) with many calcific nodules, visible on CFP. CONCLUSIONS We present the first direct clinicopathologic correlation for FAF imaging of drusen-associated atrophy. Our data support 4 FAF stages of drusen-associated atrophy. Stage 2 is the earliest detected stage in which loss of screening by photoreceptor photopigment contributes to uniform hyperautofluorescence. Stages 3 and 4 comport with incomplete RPE and outer retinal atrophy as defined by the Classification of Atrophy Meetings group. Loss of RPE, ONL, and ELM in stage 4 indicates that atrophy can begin over individual drusen. Findings will help the identification of new therapeutic approaches and clinical study end points.
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Affiliation(s)
- Ling Chen
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham Alabama, USA,The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, and Chongqing Eye Institute, Chongqing, China
| | - Jeffrey D. Messinger
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham Alabama, USA
| | | | - K. Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, NY, USA,LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, NY, USA,Department of Ophthalmology, New York University School of Medicine, New York, NY, USA,Columbia University College of Physicians and Surgeons, Harkness Eye Institute, New York, NY, USA
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham School of Medicine, Birmingham Alabama, USA,Corresponding Address: Christine A. Curcio, PhD; Department of Ophthalmology and Visual Sciences; EyeSight Foundation of Alabama Vision Research Laboratories; 1670 University Boulevard Room 360; University of Alabama School of Medicine; Birmingham AL 35294-0099;
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25
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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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26
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NATURAL HISTORY OF QUANTITATIVE AUTOFLUORESCENCE IN INTERMEDIATE AGE-RELATED MACULAR DEGENERATION. Retina 2021; 41:694-700. [PMID: 32740494 DOI: 10.1097/iae.0000000000002923] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To investigate differences in quantitative autofluorescence (qAF) imaging measurements between eyes with and without large drusen, and whether qAF measurements change over time in the eyes with large drusen. METHODS Eighty-five eyes from participants with bilateral large drusen and 51 eyes from healthy participants underwent qAF imaging at least once, and the age-related macular degeneration participants were reviewed 6-monthly. Normalized grey values at 9° to 11° eccentricity from the fovea were averaged to provide a summary measure of qAF values (termed qAF8). RESULTS In a multivariable model, qAF8 measurements were not significantly different between age-related macular degeneration eyes with large drusen and healthy eyes (P = 0.130), and qAF8 measurements showed a decline over time in the age-related macular degeneration eyes (P = 0.013). CONCLUSION These findings add to the body of evidence that qAF levels are not increased in eyes with large drusen compared with healthy eyes, and qAF levels show a significant decline over time in the age-related macular degeneration eyes. These findings highlight how the relationship between qAF levels and retinal pigment epithelium health does not seem to be straightforward. Further investigation is required to better understand this relationship, especially if qAF levels are to be used as an outcome measure in intervention trials.
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27
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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] [MESH Headings] [Grants] [Track Full Text] [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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28
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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: 12] [Impact Index Per Article: 4.0] [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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29
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Nita M, Grzybowski A. Interplay between reactive oxygen species and autophagy in the course of age-related macular degeneration. EXCLI JOURNAL 2020; 19:1353-1371. [PMID: 33192217 PMCID: PMC7658465 DOI: 10.17179/excli2020-2915] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022]
Abstract
Pathological biomolecules such as lipofuscin, methylglyoxal-modified proteins (the major precursors of advanced glycationend products), misfolding protein deposits and dysfunctional mitochondria are source of oxidative stress and act as strong autophagic stimulators in age-related macular degeneration. Disturbed autophagy accelerates progression of the disease, since it leads to retinal cells' death and activates inflammation by the interplay with the NLRP3 inflammasome complex. Vascular dysfunction and hypoxia, as well as circulating autoantibodies against autophagy regulators (anti-S100A9, anti-ANXA5, and anti-HSPA8, A9 and B4) compromise an autophagy-mediated mechanism as well. Metformin, the autophagic stimulator, may act as a senostatic drug to inhibit the senescent phenotype in the age-related macular degeneration. PGC-1α , Sirt1 and AMPK represent new therapeutic targets for interventions in this disease.
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Affiliation(s)
- Malgorzata Nita
- Domestic and Specialized Medicine Centre "Dilmed" Katowice, Poland
| | - Andrzej Grzybowski
- Department of Ophthalmolgy, Medical Faculty, University of Warmia and Mazury, Olsztyn, Poland.,Institute for Research in Ophthalmology, Poznań, Poland
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De Bruyne S, Van den Broecke C, Vrielinck H, Khelifi S, De Wever O, Bracke K, Huizing M, Boston N, Himpe J, Speeckaert M, Vral A, Van Dorpe J, Van Aken E, Delanghe JR. Fructosamine-3-Kinase as a Potential Treatment Option for Age-Related Macular Degeneration. J Clin Med 2020; 9:jcm9092869. [PMID: 32899850 PMCID: PMC7565857 DOI: 10.3390/jcm9092869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/22/2020] [Accepted: 09/03/2020] [Indexed: 12/15/2022] Open
Abstract
Age-related macular degeneration is the leading cause of blindness in the developed world. Since advanced glycation end products (AGEs) are implicated in the pathogenesis of AMD through various lines of evidence, we investigated the potential of fructosamine-3-kinase (FN3K) in the disruption of retinal AGEs, drusenoid material and drusenoid lesions in patients with AMD. AGE-type autofluorescence was measured to evaluate the effects of FN3K on glycolaldehyde-induced AGE-modified neural porcine retinas and unmodified human neural retinas. Eye pairs from cigarette-smoke- and air-exposed mice were treated and evaluated histologically. Automated optical image analysis of human tissue sections was performed to compare control- and FN3K-treated drusen and near-infrared (NIR) microspectroscopy was performed to examine biochemical differences. Optical coherence tomography (OCT) was used to evaluate the effect of FN3K on drusenoid deposits after treatment of post-mortem human eyes. FN3K treatment provoked a significant decrease (41%) of AGE-related autofluorescence in the AGE-modified porcine retinas. Furthermore, treatment of human neural retinas resulted in significant decreases of autofluorescence (−24%). FN3K-treated murine eyes showed less drusenoid material. Pairwise comparison of drusen on tissue sections revealed significant changes in color intensity after FN3K treatment. NIR microspectroscopy uncovered clear spectral differences in drusenoid material (Bruch’s membrane) and drusen after FN3K treatment. Ex vivo treatment strongly reduced size of subretinal drusenoid lesions on OCT imaging (up to 83%). In conclusion, our study demonstrated for the first time a potential role of FN3K in the disruption of AGE-related retinal autofluorescence, drusenoid material and drusenoid lesions in patients with AMD.
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Affiliation(s)
- Sander De Bruyne
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium; (S.D.B.); (J.H.); (J.V.D.)
| | | | - Henk Vrielinck
- Department of Solid State Sciences, Ghent University, 9000 Ghent, Belgium; (H.V.); (S.K.)
| | - Samira Khelifi
- Department of Solid State Sciences, Ghent University, 9000 Ghent, Belgium; (H.V.); (S.K.)
| | - Olivier De Wever
- Department of Human Structure and Repair, Ghent University, 9000 Ghent, Belgium; (O.D.W.); (A.V.)
| | - Ken Bracke
- Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium; (K.B.); (M.S.)
| | - Manon Huizing
- Biobank, Antwerp University Hospital, 2650 Antwerp, Belgium; (M.H.); (N.B.)
| | - Nezahat Boston
- Biobank, Antwerp University Hospital, 2650 Antwerp, Belgium; (M.H.); (N.B.)
| | - Jonas Himpe
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium; (S.D.B.); (J.H.); (J.V.D.)
| | - Marijn Speeckaert
- Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium; (K.B.); (M.S.)
- Research Foundation Flanders, 1000 Brussels, Belgium
| | - Anne Vral
- Department of Human Structure and Repair, Ghent University, 9000 Ghent, Belgium; (O.D.W.); (A.V.)
| | - Jo Van Dorpe
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium; (S.D.B.); (J.H.); (J.V.D.)
- Department of Pathology, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Elisabeth Van Aken
- Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
- Correspondence: (E.V.A.); (J.R.D.)
| | - Joris R. Delanghe
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium; (S.D.B.); (J.H.); (J.V.D.)
- Correspondence: (E.V.A.); (J.R.D.)
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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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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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33
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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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Bis-allylic Deuterated DHA Alleviates Oxidative Stress in Retinal Epithelial Cells. Antioxidants (Basel) 2019; 8:antiox8100447. [PMID: 31581525 PMCID: PMC6826779 DOI: 10.3390/antiox8100447] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/02/2019] [Accepted: 09/16/2019] [Indexed: 12/12/2022] Open
Abstract
Oxidative stress plays a crucial role in developing and accelerating retinal diseases including age-related macular degeneration (AMD). Docosahexaenoic acid (DHA, C22:6, n-3), the main lipid constituent of retinal epithelial cell membranes, is highly prone to radical and enzymatic oxidation leading to deleterious or beneficial metabolites for retinal tissue. To inhibit radical oxidation while preserving enzymatic metabolism, deuterium was incorporated at specific positions of DHA, resulting in D2-DHA when incorporated at position 6 and D4-DHA when incorporated at the 6,9 bis-allylic positions. Both derivatives were able to decrease DHAs’ toxicity and free radical processes involved in lipid peroxidation, in ARPE-19 cells (Adult Retinal Pigment Epithelial cell line), under pro-oxidant conditions. Our positive results encouraged us to prepare lipophenolic-deuterated-DHA conjugates as possible drug candidates for AMD treatment. These novel derivatives proved efficient in limiting lipid peroxidation in ARPE-19 cells. Finally, we evaluated the underlying mechanisms and the enzymatic conversion of both deuterated DHA. While radical abstraction was affected at the deuterium incorporation sites, enzymatic conversion by the lipoxygenase 15s-LOX was not impacted. Our results suggest that site-specifically deuterated DHA could be used in the development of DHA conjugates for treatment of oxidative stress driven diseases, or as biological tools to study the roles, activities and mechanisms of DHA metabolites.
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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: 43] [Impact Index Per Article: 8.6] [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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Qian S, Qian Y, Huo D, Wang S, Qian Q. Tanshinone IIa protects retinal endothelial cells against mitochondrial fission induced by methylglyoxal through glyoxalase 1. Eur J Pharmacol 2019; 857:172419. [PMID: 31136758 DOI: 10.1016/j.ejphar.2019.172419] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 05/24/2019] [Accepted: 05/24/2019] [Indexed: 02/06/2023]
Abstract
Advanced glycation end products (AGEs) play an important role in the onset of diabetic retinopathy. Therefore, in the current study, we investigate whether and how Tanshinone IIa (Tan IIa) from Salvia miltiorrhiza protects bovine retinal endothelial cells (BRECs) against methylglyoxal (MGO) mediated cell dysfunction. The results showed that MGO reduced cell viability in dose dependent manner. The treatment of Tan IIa (50 μM) significantly improved cell viability induced by MGO in BRECs. MGO increased cellular reactive oxygen species formation and cellular nitric oxide (NO) level; enhanced nox1 and iNOS mRNA levels; inhibited prdx1 mRNA level. The treatment of Tan IIa effectually ameliorated cellular oxidative stress. Exposure of MGO resulted in mitochondrial fission and decrease of opa1 and mfn1. No significant difference in mRNA levels of mfn2 and drp1 was detected between MGO and medium. Tan IIa reduced mitochondrial fragmentation, enhanced the mRNA levels of mfn1 and opa1 in MGO cultured BRECs. The short time exposure of cellular antioxidatants, dimethylthiourea (10 mM) and tiron (10 mM) had no effect on mitochondrial fission although they ameliorated cellular reactive oxygen species level. Moreover, overexpression of glyoxalase 1 (GLO1) increased key proteins of mitochondrial fusion, including opa1 and mfn1 in BRECs cultured with MGO. However, inhibition of GLO1 by siRNA abolished the effect of Tan IIa on induction of mitochondrial fusion in MGO cultured BRECs. In conclusion, MGO caused the injury of retinal endothelial cells through induction of mitochondrial dysfunction and mitochondrial fission, the treatment of Tan IIa ameliorated mitochondrial dysfunction and fission induced by AGEs through enhancing GLO1.
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Affiliation(s)
- Shuhong Qian
- Department of Clinical Laboratory, 1st Affiliated Hospital, Zhengzhou University, China
| | - Yujin Qian
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Australia
| | - Dongxia Huo
- College of Material Engineering, Zhengzhou University, China
| | - Shijin Wang
- Department of Clinical Laboratory, 1st Affiliated Hospital, Zhengzhou University, China
| | - Qingwen Qian
- Department of Internal Medicine, 1st Affiliated Hospital, Zhengzhou University, China.
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Ostrovsky MA, Dontsov AE. Vertebrate Eye Melanosomes and Invertebrate Eye Ommochromes as Antioxidant Cell Organelles: Part 2. BIOL BULL+ 2019. [DOI: 10.1134/s1062359019010084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Leclaire MD, Nettels-Hackert G, König J, Höhn A, Grune T, Uhlig CE, Hansen U, Eter N, Heiduschka P. Lipofuscin-dependent stimulation of microglial cells. Graefes Arch Clin Exp Ophthalmol 2019; 257:931-952. [PMID: 30693383 DOI: 10.1007/s00417-019-04253-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 01/10/2019] [Accepted: 01/17/2019] [Indexed: 01/10/2023] Open
Abstract
PURPOSE To examine the reaction of microglial cells (MG) when incubated with lipofuscin (LP) in vitro with emphasis on the immunological reaction of the MG toward LP and the suppression of this reaction by immunomodulatory agents. MG are involved in the pathogenesis of degenerative eye disorders such as age-related macular degeneration (AMD). LP is a heterogeneous waste material that accumulates in the retinal pigment epithelium (RPE) cells with advancing age. LP is known to have toxic effects on RPE cells and therefore an elevated LP-derived fundus autofluorescence is a risk factor for AMD development. MG in the subretinal space have been reported in eyes affected by AMD. Moreover, in senescent mice, subretinal MG were found, which display an autofluorescence that may be derived from LP uptake. METHODS In this study, we incubated MG (BV-2 cell line and primary cells from murine brain) in vitro with LP isolated from the human RPE. We observed phagocytosis, studied cell morphologies, and analyzed the cell culture supernatants. We also investigated the effect of the immunomodulatory agents hydrocortisone (HC), minocycline, and the tripeptide TKP. RESULTS The MG phagocytosed the LP quickly and completely. We detected highly elevated levels of pro-inflammatory cytokines (especially of IL-6, IL-23p19, TNF-α, KC, RANTES, and IL-1α) in the cell culture supernatants. Furthermore, levels of vascular endothelial growth factor (VEGF) were raised in BV-2 cells. Anti-inflammatory agents added to the cell cultures inhibited the inflammatory reaction, in particular hydrocortisone (HC). Minocycline and TKP had less impact on the cytokine release. CONCLUSION The interaction of MG and LP could play a role in the development of retinal degeneration by triggering an inflammatory reaction and angiogenesis.
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Affiliation(s)
- Martin Dominik Leclaire
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany
| | - Gerburg Nettels-Hackert
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany
| | - Jeannette König
- German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany
| | - Annika Höhn
- German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany
| | - Tilman Grune
- German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany
| | - Constantin E Uhlig
- Cornea Bank Münster, Department of Ophthalmology, University Medical Center, Münster, Germany
| | - Uwe Hansen
- Institute of Experimental Musculoskeletal Medicine, Medical Faculty, University of Münster, Münster, Germany
| | - Nicole Eter
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany
| | - Peter Heiduschka
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany.
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Bittencourt MG, Hassan M, Halim MS, Afridi R, Nguyen NV, Plaza C, Tran ANT, Ahmed MI, Nguyen QD, Sepah YJ. Blue light versus green light fundus autofluorescence in normal subjects and in patients with retinochoroidopathy secondary to retinal and uveitic diseases. J Ophthalmic Inflamm Infect 2019; 9:1. [PMID: 30617430 PMCID: PMC6325057 DOI: 10.1186/s12348-018-0167-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 12/20/2018] [Indexed: 11/10/2022] Open
Abstract
PURPOSE The aim of this study is to evaluate the differences in the fundus autofluorescence (FAF) signal between the blue light autofluorescence (BAF) from Spectralis® (Heidelberg, CA) and green light autofluorescence (GAF) 200TxTM (OPTOS, UK, in normal subjects and in patients with retinochoroidopathies (RC). METHODS In this prospective study, FAF was performed using BL (λ = 488 nm) and GL (λ = 532 nm) on normal subjects and patients with RC. The corresponding pairs of BAF and GAF images from both groups were analyzed using Photoshop. The strength of the FAF signal was measured on a gray scale, where optic disc was a standard to indicate absence of AF. In addition, gray values obtained from three identical points (foveal center, and points of hypo and hyper autofluorescence) in the corresponding BAF and GAF images of normal and RC subjects were divided by the optic disc value to calculate autofluorescence signal ratio (R). The R values at fovea (R1), hypoautofluorescent point (R2), and hyperautofluorescent point (R3) were compared between BAF and GAF modalities, in normal and in RC subjects separately. RESULTS One hundred six pairs (106 eyes) of FAF images analyzed (37 pairs: normal and 69 pairs: RC subjects). In normal subjects, the mean R1, R2, and R3 values for BAF were (1.5 ± 0.88, 1.23 ± 0.58, and 4.73 ± 2.85, respectively) and for GAF were (0.78 ± 0.20, 0.78 ± 0.20, and 1.62 ± 0.39, respectively). Similarly, in subjects with RC, the mean R1, R2, and R3 values for BAF were (1.68 ± 1.02, 1.66 ± 1.15, and 7.75 ± 6.82, respectively) and for GAF were (0.95 ± 0.59, 0.79 ± 0.45, and 2.50 ± 1.65, respectively). The mean difference in the R1, R2, and R3 ratios between BAF and GAF in normal and in RC subjects was statistically significant (p < 0.001). The strength of the correlation (r) between ratios for BAF and GAF was weak or not statistically significant in both normal and RC subjects (p > 0.05). CONCLUSION The distribution and intensity of the AF signal differ in BAF and GAF and cannot be used interchangeably. In BAF, optic disc signal is always weaker than in other areas, which was not true for GAF where optic disc signal was stronger than fovea and hypoautofluorescent point in both groups.
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Affiliation(s)
| | - Muhammad Hassan
- Byers Eye Institute, Stanford University, 2370 Watson Court, Suite 200, Palo Alto, CA, 94303, USA
| | - Muhammad Sohail Halim
- Byers Eye Institute, Stanford University, 2370 Watson Court, Suite 200, Palo Alto, CA, 94303, USA
| | - Rubbia Afridi
- Byers Eye Institute, Stanford University, 2370 Watson Court, Suite 200, Palo Alto, CA, 94303, USA
| | - Nam V Nguyen
- Ocular Imaging Research and Reading Center, Menlo Park, CA, USA.,Byers Eye Institute, Stanford University, 2370 Watson Court, Suite 200, Palo Alto, CA, 94303, USA
| | - Carlos Plaza
- Byers Eye Institute, Stanford University, 2370 Watson Court, Suite 200, Palo Alto, CA, 94303, USA
| | - Anh N T Tran
- Byers Eye Institute, Stanford University, 2370 Watson Court, Suite 200, Palo Alto, CA, 94303, USA
| | | | - Quan Dong Nguyen
- Byers Eye Institute, Stanford University, 2370 Watson Court, Suite 200, Palo Alto, CA, 94303, USA
| | - Yasir Jamal Sepah
- Byers Eye Institute, Stanford University, 2370 Watson Court, Suite 200, Palo Alto, CA, 94303, USA.
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Curcio CA. Soft Drusen in Age-Related Macular Degeneration: Biology and Targeting Via the Oil Spill Strategies. Invest Ophthalmol Vis Sci 2018; 59:AMD160-AMD181. [PMID: 30357336 PMCID: PMC6733535 DOI: 10.1167/iovs.18-24882] [Citation(s) in RCA: 188] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AMD is a major cause of legal blindness in older adults approachable through multidisciplinary research involving human tissues and patients. AMD is a vascular-metabolic-inflammatory disease, in which two sets of extracellular deposits, soft drusen/basal linear deposit (BLinD) and subretinal drusenoid deposit (SDD), confer risk for end-stages of atrophy and neovascularization. Understanding how deposits form can lead to insights for new preventions and therapy. The topographic correspondence of BLinD and SDD with cones and rods, respectively, suggest newly realized exchange pathways among outer retinal cells and across Bruch's membrane and the subretinal space, in service of highly evolved, eye-specific physiology. This review focuses on soft drusen/BLinD, summarizing evidence that a major ultrastructural component is large apolipoprotein B,E-containing, cholesterol-rich lipoproteins secreted by the retinal pigment epithelium (RPE) that offload unneeded lipids of dietary and outer segment origin to create an atherosclerosis-like progression in the subRPE-basal lamina space. Clinical observations and an RPE cell culture system combine to suggest that soft drusen/BLinD form when secretions of functional RPE back up in the subRPE-basal lamina space by impaired egress across aged Bruch's membrane-choriocapillary endothelium. The soft drusen lifecycle includes growth, anterior migration of RPE atop drusen, then collapse, and atrophy. Proof-of-concept studies in humans and animal models suggest that targeting the “Oil Spill in Bruch's membrane” offers promise of treating a process in early AMD that underlies progression to both end-stages. A companion article addresses the antecedents of soft drusen within the biology of the macula.
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Affiliation(s)
- Christine A Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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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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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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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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Banevicius M, Vilkeviciute A, Kriauciuniene L, Liutkeviciene R, Deltuva VP. The Association Between Variants of Receptor for Advanced Glycation End Products (RAGE) Gene Polymorphisms and Age-Related Macular Degeneration. Med Sci Monit 2018; 24:190-199. [PMID: 29317590 PMCID: PMC5771184 DOI: 10.12659/msm.905311] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Background Age-related macular degeneration (AMD) is the leading cause of blindness in people aged 65 years and older in developed countries. The pathogenesis of AMD has been linked to mechanisms involving inflammation, oxidative stress, and basal laminar deposit formation between retinal pigment epithelium (RPE) cells and the basal membrane, caused by advanced glycation end products (AGEs). AGEs are implicated in the pathogenesis of AMD through the AGE-and receptor for AGE (RAGE) interaction, which can be altered by polymorphisms of the RAGE gene. We examined RAGE rs1800624 and rs1800625 gene polymorphisms contributing to AMD development. Material/Methods The study enrolled 300 patients with early AMD, 300 patients with exudative AMD, and 800 healthy controls. The genotyping was carried out using the RT-PCR method. Results The analysis of two single nucleotide polymorphisms (SNPs) in the RAGE gene showed that rs1800624 was associated with a 1.6-fold decreased risk for exudative AMD under the dominant model after adjustment for age (OR=0.616; 95% CI: 0.394–0.963; p=0.034) and each copy of allele T at rs1800624 was associated with a 1.4-fold decreased risk for exudative AMD development under the additive model after adjustment for age (OR=0.701; 95% CI: 0.510–0.962; p=0.028). Analysis revealed that the rs1800625 allele G at rs1800625 was associated with a 1.5-fold increased risk for exudative AMD after adjustment for age (OR=1.545; 95% CI: 1.003–2.379; p=0.048). These results suggested that the allele G at rs1800625 was a risk-allele for exudative AMD development. In haplotype analysis, A-G haplotype was significantly more frequently observed in exudative AMD patients compared to healthy controls (3.3% versus 1.4%, p=0.035). Conclusions We revealed a significant association between RAGE gene rs1800624 and rs1800625 polymorphisms and AMD risk. We considered T allele at rs1800624 to be protective against AMD development, while allele G at rs1800625 was considered to be a marker of poor prognosis in AMD development.
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Affiliation(s)
- Mantas Banevicius
- Department of Ophthalmology, Lithuanian University of Health Sciences, Medical Academy, Kaunas, Lithuania
| | - Alvita Vilkeviciute
- Neuroscience Institute, Lithuanian University of Health Sciences, Medical Academy, Kaunas, Lithuania
| | - Loresa Kriauciuniene
- Department of Ophthalmology, Lithuanian University of Health Sciences, Medical Academy, Kaunas, Lithuania.,Neuroscience Institute, Lithuanian University of Health Sciences, Medical Academy, Kaunas, Lithuania
| | - Rasa Liutkeviciene
- Department of Ophthalmology, Lithuanian University of Health Sciences, Medical Academy, Kaunas, Lithuania.,Neuroscience Institute, Lithuanian University of Health Sciences, Medical Academy, Kaunas, Lithuania
| | - Vytenis Pranas Deltuva
- Neuroscience Institute, Lithuanian University of Health Sciences, Medical Academy, Kaunas, Lithuania
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Xu Q, Cao S, Rajapakse S, Matsubara JA. Understanding AMD by analogy: systematic review of lipid-related common pathogenic mechanisms in AMD, AD, AS and GN. Lipids Health Dis 2018; 17:3. [PMID: 29301530 PMCID: PMC5755337 DOI: 10.1186/s12944-017-0647-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/17/2017] [Indexed: 12/15/2022] Open
Abstract
RATIONALE Age-related macular degeneration (AMD) is one of the leading causes of blindness among the elderly. Due to its complex etiology, current treatments have been insufficient. Previous studies reveal three systems closely involved in AMD pathogenesis: lipid metabolism, oxidation and inflammation. These systems are also involved in Alzheimer's disease, atherosclerosis and glomerulonephritis. Understanding commonalities of these four diseases may provide insight into AMD etiology. OBJECTIVES To understand AMD pathogenesis by analogy and suggest ideas for future research, this study summarizes main commonalities in disease pathogenesis of AMD, Alzheimer's disease, atherosclerosis and glomerulonephritis. METHODS Articles were identified through PubMed, Ovid Medline and Google Scholar. We summarized the common findings and synthesized critical differences. RESULTS Oxidation, lipid deposition, complement activation, and macrophage recruitment are involved in all four diseases shown by genetic, molecular, animal and human studies. Shared genetic variations further strengthen their connection. Potential areas for future research are suggested throughout the review. CONCLUSIONS The four diseases share many steps of an overall framework of pathogenesis. Various oxidative sources cause oxidative stress. Oxidized lipids and related molecules accumulate and lead to complement activation, macrophage recruitment and pathology. Investigations that arise under this structure may aid us to better understand AMD pathology.
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Affiliation(s)
- Qinyuan Xu
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 3N9 Canada
| | - Sijia Cao
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 3N9 Canada
| | - Sanjeeva Rajapakse
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 3N9 Canada
| | - Joanne A. Matsubara
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 3N9 Canada
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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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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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Stress responses of human retinal pigment epithelial cells to glyoxal. Graefes Arch Clin Exp Ophthalmol 2016; 254:2361-2372. [PMID: 27520463 DOI: 10.1007/s00417-016-3463-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 07/04/2016] [Accepted: 08/01/2016] [Indexed: 10/21/2022] Open
Abstract
PURPOSE Intracellular formation of advanced glycation end products (AGEs) is a crucial pathological process in retinal diseases such as age-related macular degeneration (AMD) or diabetic retinopathy (DR). Glyoxal is a physiological metabolite produced during formation of AGEs and has also been shown to derive from photodegraded bisretinoid fluorophores in aging retinal pigment epithelial (RPE) cells. METHODS Flow cytometry was combined with either: 1) immunocytochemical staining to detect glyoxal induced formation of Nε-carboxymethyllysine (CML)-modifications of intracellular proteins (AGEs) and changes in the production of stress response proteins; or 2) vital staining to determine apoptosis rates (annexin V binding), formation of intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and changes in intracellular pH upon treatment of cells with glyoxal. The percentage of apoptotic cells was further quantified by flow cytometry after staining of fixed cells with propidium iodide to determine cells with a subdiploid (fragmented) DNA content. Apoptosis related activation of caspase 3 was determined by Western blotting. Glyoxal induced changes in VEGF-A165a mRNA expression and protein production were determined by real-time PCR and by flow cytometry after immunocytochemical staining. RESULTS Increasing glyoxal concentrations resulted in enhanced formation of AGEs, such as CML modifications of proteins. This was associated with elevated levels of intracellular reactive oxygen species, a depolarized MMP, and a decreased intracellular pH, resulting in an increased number of apoptotic cells. Apoptosis related caspase 3 activation increased in a dose dependent manner after glyoxal incubation. In consequence, the cells activated compensatory mechanisms and increased the levels of the anti-oxidative and stress-related proteins heme oxygenase-1, osteopontin, heat shock protein 27, copper/zinc superoxide dismutase, manganese superoxide dismutase, and cathepsin D. Furthermore, VEGF-A165a mRNA expression and VEGF-A protein production were significantly increased after incubation with glyoxal in ARPE-19 cells. CONCLUSIONS The glyoxal-induced oxidative stress and apoptosis in ARPE-19 cells may provide a suitable in vitro model for studying RPE cellular reactions to AGEs that occur in AMD or in DR.
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Yakovleva MA, Gulin AA, Feldman TB, Bel’skich YC, Arbukhanova PM, Astaf’ev AA, Nadtochenko VA, Borzenok SA, Ostrovsky MA. Time-of-flight secondary ion mass spectrometry to assess spatial distribution of A2E and its oxidized forms within lipofuscin granules isolated from human retinal pigment epithelium. Anal Bioanal Chem 2016; 408:7521-8. [DOI: 10.1007/s00216-016-9854-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 07/24/2016] [Accepted: 08/01/2016] [Indexed: 11/25/2022]
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Chan CM, Huang DY, Huang YP, Hsu SH, Kang LY, Shen CM, Lin WW. Methylglyoxal induces cell death through endoplasmic reticulum stress-associated ROS production and mitochondrial dysfunction. J Cell Mol Med 2016; 20:1749-60. [PMID: 27307396 PMCID: PMC4988286 DOI: 10.1111/jcmm.12893] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/03/2016] [Indexed: 12/30/2022] Open
Abstract
Diabetic retinopathy (DR) and age‐related macular degeneration (AMD) are two important leading causes of acquired blindness in developed countries. As accumulation of advanced glycation end products (AGEs) in retinal pigment epithelial (RPE) cells plays an important role in both DR and AMD, and the methylglyoxal (MGO) within the AGEs exerts irreversible effects on protein structure and function, it is crucial to understand the underlying mechanism of MGO‐induced RPE cell death. Using ARPE‐19 as the cell model, this study revealed that MGO induces RPE cell death through a caspase‐independent manner, which relying on reactive oxygen species (ROS) formation, mitochondrial membrane potential (MMP) loss, intracellular calcium elevation and endoplasmic reticulum (ER) stress response. Suppression of ROS generation can reverse the MGO‐induced ROS production, MMP loss, intracellular calcium increase and cell death. Moreover, store‐operated calcium channel inhibitors MRS1845 and YM‐58483, but not the inositol 1,4,5‐trisphosphate (IP3) receptor inhibitor xestospongin C, can block MGO‐induced ROS production, MMP loss and sustained intracellular calcium increase in ARPE‐19 cells. Lastly, inhibition of ER stress by salubrinal and 4‐PBA can reduce the MGO‐induced intracellular events and cell death. Therefore, our data indicate that MGO can decrease RPE cell viability, resulting from the ER stress‐dependent intracellular ROS production, MMP loss and increased intracellular calcium increase. As MGO is one of the components of drusen in AMD and is the AGEs adduct in DR, this study could provide a valuable insight into the molecular pathogenesis and therapeutic intervention of AMD and DR.
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Affiliation(s)
- Chi-Ming Chan
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Ophthalmology, Cardinal Tien Hospital, New Taipei City, Taiwan.,School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Duen-Yi Huang
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Pin Huang
- Medical Research Center, Cardinal Tien Hospital, New Taipei City, Taiwan
| | - Shu-Hao Hsu
- Medical Research Center, Cardinal Tien Hospital, New Taipei City, Taiwan
| | - Lan-Ya Kang
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chung-Min Shen
- Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan
| | - Wan-Wan Lin
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
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