1
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Rahman B, Anderson DMG, Chen C, Liu J, Migas LG, Van de Plas R, Schey KL, Kono M, Fan J, Koutalos Y. Sphingolipid Levels and Processing of the Retinyl Chromophore in the Retina of a Mouse Model of Niemann-Pick Disease. Invest Ophthalmol Vis Sci 2024; 65:24. [PMID: 39661357 PMCID: PMC11640910 DOI: 10.1167/iovs.65.14.24] [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: 07/18/2024] [Accepted: 11/21/2024] [Indexed: 12/12/2024] Open
Abstract
Purpose Mutations in the gene that encodes the enzyme acid sphingomyelinase (ASMase) are associated with Niemann-Pick disease, a lysosomal storage disorder. Mice that lack ASMase (ASMase-/-) exhibit age-related retinal degeneration and large increases in accumulation of lipofuscin in the retinal pigment epithelium (RPE). We examined which lipid species accumulate in the retina and the RPE of ASMase-/- mice and whether the retinal degeneration is associated with impaired photoreceptor metabolism and retinyl chromophore processing. Methods NADPH availability and all-trans retinol formation after rhodopsin bleaching were measured in isolated single rod photoreceptors with fluorescence imaging; sphingolipid levels in retinas and RPEs were measured with LC/MS; relative abundances of different lipid species in different retinal layers were measured with MALDI imaging mass spectrometry. Results There was no detectable difference in the kinetics of all-trans retinol formation or the NADPH-generating capacity between ASMase-/- and wild-type mice. Sphingomyelin levels were much higher in the retinas and RPEs of ASMase-/- animals compared to wild type, but there were no significant differences for ceramides. There was a large increase in the abundance of bis(monoacylglycero)phosphates (BMPs) in ASMase-/- mice, indicative of lysosomal dysfunction, but no substantial changes were detected for the bis-retinoid A2E. Conclusions Lysosomal dysfunction and retinal degeneration in ASMase-/- mice are not associated with defects in rod photoreceptor metabolism that affect all-trans retinol formation and availability of NADPH. Lysosomal dysfunction in ASMase-/- mice is not associated with bis-retinoid A2E accumulation.
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Affiliation(s)
- Bushra Rahman
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - David M. G. Anderson
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, Unites States
| | - Chunhe Chen
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Jian Liu
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Lukasz G. Migas
- Delft Center for Systems and Control (DCSC), Delft University of Technology, Delft, Netherlands
| | - Raf Van de Plas
- Delft Center for Systems and Control (DCSC), Delft University of Technology, Delft, Netherlands
| | - Kevin L. Schey
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, Unites States
| | - Masahiro Kono
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Jie Fan
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Yiannis Koutalos
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
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2
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Faatz H, Lommatzsch AP. [Age-related macular degeneration - Part 1: Pathophysiology, classification and diagnostic]. Klin Monbl Augenheilkd 2024. [PMID: 39255815 DOI: 10.1055/a-2367-8346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Age-related macular degeneration (AMD) continues to be the most common hereditary disease among older people in the western world. In addition to the clinical examination, multimodal imaging with fluorescein angiography, optical coherence tomography, fundus autofluorescence and fundus photography are crucial for the correct diagnosis and classification. This is particularly important with regard to risk assessment for the development of a late form of the disease. Since the introduction of intravitreal therapy against vascular endothelial growth factor (VEGF), the treatment options for neovascular AMD have increased significantly and the prognosis for patients in terms of maintaining their vision has improved. The hope is to develop stronger and longer-lasting drugs and also to obtain approval for drugs to treat geographic atrophy. It is therefore of great importance to be able to make a quick and correct diagnosis for patients. In this paper we want to present an overview of the pathophysiology, classification and diagnosis of AMD.
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3
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Cvekl A, Vijg J. Aging of the eye: Lessons from cataracts and age-related macular degeneration. Ageing Res Rev 2024; 99:102407. [PMID: 38977082 DOI: 10.1016/j.arr.2024.102407] [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: 03/11/2024] [Revised: 06/18/2024] [Accepted: 07/01/2024] [Indexed: 07/10/2024]
Abstract
Aging is the greatest risk factor for chronic human diseases, including many eye diseases. Geroscience aims to understand the effects of the aging process on these diseases, including the genetic, molecular, and cellular mechanisms that underlie the increased risk of disease over the lifetime. Understanding of the aging eye increases general knowledge of the cellular physiology impacted by aging processes at various biological extremes. Two major diseases, age-related cataract and age-related macular degeneration (AMD) are caused by dysfunction of the lens and retina, respectively. Lens transparency and light refraction are mediated by lens fiber cells lacking nuclei and other organelles, which provides a unique opportunity to study a single aging hallmark, i.e., loss of proteostasis, within an environment of limited metabolism. In AMD, local dysfunction of the photoreceptors/retinal pigmented epithelium/Bruch's membrane/choriocapillaris complex in the macula leads to the loss of photoreceptors and eventually loss of central vision, and is driven by nearly all the hallmarks of aging and shares features with Alzheimer's disease, Parkinson's disease, cardiovascular disease, and diabetes. The aging eye can function as a model for studying basic mechanisms of aging and, vice versa, well-defined hallmarks of aging can be used as tools to understand age-related eye disease.
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Affiliation(s)
- Ales Cvekl
- Departments of Genetics and Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Jan Vijg
- Departments of Genetics and Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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4
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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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Lima LH, Braga JPR, Melo GB, Cella WP, Brandão ASL, Meirelles RL, Zett C, Cyrino FVR, Jorge R. Serous maculopathy with absence of retinal pigment epithelium (SMARPE) associated with large drusen. Int J Retina Vitreous 2024; 10:8. [PMID: 38254230 PMCID: PMC10802009 DOI: 10.1186/s40942-024-00529-5] [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: 12/02/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
PURPOSE To describe the association of serous maculopathy with absence of retinal pigment epithelium (SMARPE) and large drusen in patients with non-neovascular age-related macular degeneration (AMD). METHODS A retrospective study of ophthalmic examination and multimodal imaging data of individuals with SMARPE and large drusen observed over a period of 12-month was accomplished. SMARPE was defined as subretinal accumulation of fluid within the macular area due to retinal pigment epithelium (RPE) aperture. Large drusen were identified by the presence of sub-RPE deposits using multimodal imaging analysis (color fundus photography, fundus autofluorescence, and spectral-domain optical coherence tomography). RESULTS Twelve eyes of 7 white patients with a mean age of 77 years were observed to have SMARPE associated with large drusen. The median visual acuity was 20/100. Bilateral SMARPE lesions were observed in 71% of study patients. All SMARPE lesions were hypoautofluorescent, located in the subretinal space between the RPE and the ellipsoid zone, and presented as complete or incomplete RPE apertures associated with subretinal fluid. The SMARPE in this study had coincident multimodal imaging features as the SMARPE described in other reports in the literature. CONCLUSIONS Bilateral SMARPE can occur in association with typical AMD large drusen. Anomalisms resulting in drusen biogenesis or mechanisms that act alongside to these may be related to SMARPE development.
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Affiliation(s)
- Luiz H Lima
- Department of Ophthalmology, Federal University of São Paulo (UNIFESP), Rua Botucatu, 821, Vila Clementino, São Paulo, 04023-062, Brazil.
| | - João Pedro Romero Braga
- Division of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Gustavo B Melo
- Department of Ophthalmology, Federal University of São Paulo (UNIFESP), Rua Botucatu, 821, Vila Clementino, São Paulo, 04023-062, Brazil
| | - Wener P Cella
- Hospital de Referência Oftalmológica, São Luís, Maranhão, Brazil
| | - Adam S L Brandão
- Hospital de Referência Oftalmológica, São Luís, Maranhão, Brazil
| | - Rodrigo L Meirelles
- Department of Ophthalmology, Federal University of São Paulo (UNIFESP), Rua Botucatu, 821, Vila Clementino, São Paulo, 04023-062, Brazil
| | - Claudio Zett
- Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Francyne V R Cyrino
- Division of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Rodrigo Jorge
- Division of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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6
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Gao F, Tom E, Lieffrig SA, Finnemann SC, Skowronska-Krawczyk D. A novel quantification method for retinal pigment epithelium phagocytosis using a very-long-chain polyunsaturated fatty acids-based strategy. Front Mol Neurosci 2023; 16:1279457. [PMID: 37928068 PMCID: PMC10622967 DOI: 10.3389/fnmol.2023.1279457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023] Open
Abstract
Introduction The vertebrate retinal pigment epithelium (RPE) lies adjacent to the photoreceptors and is responsible for the engulfment and degradation of shed photoreceptor outer segment fragments (POS) through receptor-mediated phagocytosis. Phagocytosis of POS is critical for maintaining photoreceptor function and is a key indicator of RPE functionality. Popular established methods to assess RPE phagocytosis rely mainly on quantifying POS proteins, especially their most abundant protein rhodopsin, or on fluorescent dye conjugation of bulk, unspecified POS components. While these approaches are practical and quantitative, they fail to assess the fate of POS lipids, which make up about 50% of POS by dry weight and whose processing is essential for life-long functionality of RPE and retina. Methods We have developed a novel very-long-chain polyunsaturated fatty acids (VLC-PUFA)-based approach for evaluating RPE phagocytic activity by primary bovine and rat RPE and the human ARPE-19 cell line and validated its results using traditional methods. Results and discussion This new approach can be used to detect in vitro the dynamic process of phagocytosis at varying POS concentrations and incubation times and offers a robust, unbiased, and reproducible assay that will have utility in studies of POS lipid processing.
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Affiliation(s)
- Fangyuan Gao
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, United States
| | - Emily Tom
- Department of Physiology and Biophysics, Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, United States
| | - Stephanie A. Lieffrig
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, New York, NY, United States
| | - Silvia C. Finnemann
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, New York, NY, United States
| | - Dorota Skowronska-Krawczyk
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, United States
- Department of Physiology and Biophysics, Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, United States
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7
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Lieffrig SA, Gyimesi G, Mao Y, Finnemann SC. Clearance phagocytosis by the retinal pigment epithelial during photoreceptor outer segment renewal: Molecular mechanisms and relation to retinal inflammation. Immunol Rev 2023; 319:81-99. [PMID: 37555340 PMCID: PMC10615845 DOI: 10.1111/imr.13264] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 07/18/2023] [Indexed: 08/10/2023]
Abstract
Mammalian photoreceptor outer segment renewal is a highly coordinated process that hinges on timed cell signaling between photoreceptor neurons and the adjacent retinal pigment epithelial (RPE). It is a strictly rhythmic, synchronized process that underlies in part circadian regulation. We highlight findings from recently developed methods that quantify distinct phases of outer segment renewal in retinal tissue. At light onset, outer segments expose the conserved "eat-me" signal phosphatidylserine exclusively at their distal, most aged tip. A coordinated two-receptor efferocytosis process follows, in which ligands bridge outer segment phosphatidylserine with the RPE receptors αvβ5 integrin, inducing cytosolic signaling toward Rac1 and focal adhesion kinase/MERTK, and with MERTK directly, additionally inhibiting RhoA/ROCK and thus enabling F-actin dynamics favoring outer segment fragment engulfment. Photoreceptors and RPE persist for life with each RPE cell in the eye servicing dozens of overlying photoreceptors. Thus, RPE cells phagocytose more often and process more material than any other cell type. Mutant mice with impaired outer segment renewal largely retain functional photoreceptors and retinal integrity. However, when anti-inflammatory signaling in the RPE via MERTK or the related TYRO3 is lacking, catastrophic inflammation leads to immune cell infiltration that swiftly destroys the retina causing blindness.
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Affiliation(s)
- Stephanie A. Lieffrig
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY
| | - Gavin Gyimesi
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY
| | | | - Silvia C. Finnemann
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY
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8
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Shome I, Thathapudi NC, Aramati BMR, Kowtharapu BS, Jangamreddy JR. Stages, pathogenesis, clinical management and advancements in therapies of age-related macular degeneration. Int Ophthalmol 2023; 43:3891-3909. [PMID: 37347455 DOI: 10.1007/s10792-023-02767-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 06/08/2023] [Indexed: 06/23/2023]
Abstract
Age-related macular degeneration (AMD) is a retinal degenerative disorder prevalent in the elderly population, which leads to the loss of central vision. The disease progression can be managed, if not prevented, either by blocking neovascularization ("wet" form of AMD) or by preserving retinal pigment epithelium and photoreceptor cells ("dry" form of AMD). Although current therapeutic modalities are moderately successful in delaying the progression and management of the disease, advances over the past years in regenerative medicine using iPSC, embryonic stem cells, advanced materials (including nanomaterials) and organ bio-printing show great prospects in restoring vision and efficient management of either forms of AMD. This review focuses on the molecular mechanism of the disease, model systems (both cellular and animal) used in studying AMD, the list of various regenerative therapies and the current treatments available. The article also highlights on the recent clinical trials using regenerative therapies and management of the disease.
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Affiliation(s)
- Ishita Shome
- UR Advanced Therapeutics Private Limited, ASPIRE-BioNest, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, India
| | - Neethi C Thathapudi
- Centre de Recherche Hôpital Maisonneuve-Rosemont, Montréal, QC, Canada
- Department of Ophthalmology and Institute of Biomedical Engineering, Université de Montréal, Montréal, QC, Canada
| | - Bindu Madhav Reddy Aramati
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, India
| | - Bhavani S Kowtharapu
- UR Advanced Therapeutics Private Limited, ASPIRE-BioNest, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, India
| | - Jaganmohan R Jangamreddy
- UR Advanced Therapeutics Private Limited, ASPIRE-BioNest, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, India.
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9
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Farnoodian M, Bose D, Barone F, Nelson LM, Boyle M, Jun B, Do K, Gordon W, Guerin MAK, Perera R, Ji JX, Cogliati T, Sharma R, Brooks BP, Bazan NG, Bharti K. Retina and RPE lipid profile changes linked with ABCA4 associated Stargardt's maculopathy. Pharmacol Ther 2023; 249:108482. [PMID: 37385300 PMCID: PMC10530239 DOI: 10.1016/j.pharmthera.2023.108482] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/20/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Stargardt maculopathy, caused predominantly by mutations in the ABCA4 gene, is characterized by an accumulation of non-degradable visual pigment derivative, lipofuscin, in the retinal pigment epithelium (RPE) - resulting in RPE atrophy. RPE is a monolayer tissue located adjacent to retinal photoreceptors and regulates their health and functioning; RPE atrophy triggers photoreceptor cell death and vision loss in Stargardt patients. Previously, ABCA4 mutations in photoreceptors were thought to be the major contributor to lipid homeostasis defects in the eye. Recently, we demonstrated that ABCA4 loss of function in the RPE leads to cell-autonomous lipid homeostasis defects. Our work underscores that an incomplete understanding of lipid metabolism and lipid-mediated signaling in the retina and RPE are potential causes for lacking treatments for this disease. Here we report altered lipidomic in mouse and human Stargardt models. This work provides the basis for therapeutics that aim to restore lipid homeostasis in the retina and the RPE.
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Affiliation(s)
- Mitra Farnoodian
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Devika Bose
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Francesca Barone
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Luke Mathew Nelson
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Marisa Boyle
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Bokkyoo Jun
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Khanh Do
- Faculty of Medicine, Phenikaa University, Hanoi, Viet Nam
| | - William Gordon
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Marie-Audrey Kautzmann Guerin
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Rasangi Perera
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Jeff X Ji
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Tiziana Cogliati
- Division of Aging Biology, National Institute on Aging, National Institute of Health, Bethesda, MD, USA
| | - Ruchi Sharma
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Nicolas G Bazan
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Kapil Bharti
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA.
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10
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Abstract
Endogenous photosensitizers play a critical role in both beneficial and harmful light-induced transformations in biological systems. Understanding their mode of action is essential for advancing fields such as photomedicine, photoredox catalysis, environmental science, and the development of sun care products. This review offers a comprehensive analysis of endogenous photosensitizers in human skin, investigating the connections between their electronic excitation and the subsequent activation or damage of organic biomolecules. We gather the physicochemical and photochemical properties of key endogenous photosensitizers and examine the relationships between their chemical reactivity, location within the skin, and the primary biochemical events following solar radiation exposure, along with their influence on skin physiology and pathology. An important take-home message of this review is that photosensitization allows visible light and UV-A radiation to have large effects on skin. The analysis presented here unveils potential causes for the continuous increase in global skin cancer cases and emphasizes the limitations of current sun protection approaches.
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Affiliation(s)
- Erick L Bastos
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Frank H Quina
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
- Department of Chemical Engineering, Polytechnic School, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Maurício S Baptista
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
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11
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Si Z, Zheng Y, Zhao J. The Role of Retinal Pigment Epithelial Cells in Age-Related Macular Degeneration: Phagocytosis and Autophagy. Biomolecules 2023; 13:901. [PMID: 37371481 DOI: 10.3390/biom13060901] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/11/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
Age-related macular degeneration (AMD) causes vision loss in the elderly population. Dry AMD leads to the formation of Drusen, while wet AMD is characterized by cell proliferation and choroidal angiogenesis. The retinal pigment epithelium (RPE) plays a key role in AMD pathogenesis. In particular, helioreceptor renewal depends on outer segment phagocytosis of RPE cells, while RPE autophagy can protect cells from oxidative stress damage. However, when the oxidative stress burden is too high and homeostasis is disturbed, the phagocytosis and autophagy functions of RPE become damaged, leading to AMD development and progression. Hence, characterizing the roles of RPE cell phagocytosis and autophagy in the pathogenesis of AMD can inform the development of potential therapeutic targets to prevent irreversible RPE and photoreceptor cell death, thus protecting against AMD.
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Affiliation(s)
- Zhibo Si
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Yajuan Zheng
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Jing Zhao
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
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12
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Zhang Q, Autterson G, Miller JML. Improved Lipofuscin Models and Quantification of Outer Segment Phagocytosis Capacity in Highly Polarized Human Retinal Pigment Epithelial Cultures. J Vis Exp 2023:10.3791/65242. [PMID: 37125790 PMCID: PMC10306344 DOI: 10.3791/65242] [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] [Indexed: 05/02/2023] Open
Abstract
The daily phagocytosis of photoreceptor outer segments by the retinal pigment epithelium (RPE) contributes to the accumulation of an intracellular aging pigment termed lipofuscin. The toxicity of lipofuscin is well established in Stargardt's disease, the most common inherited retinal degeneration, but is more controversial in age-related macular degeneration (AMD), the leading cause of irreversible blindness in the developed world. Determining lipofuscin toxicity in humans has been difficult, and animal models of Stargardt's have limited toxicity. Thus, in vitro models that mimic human RPE in vivo are needed to better understand lipofuscin generation, clearance, and toxicity. The majority of cell culture lipofuscin models to date have been in cell lines or have involved feeding RPE a single component of the complex lipofuscin mixture rather than fragments/tips of the entire photoreceptor outer segment, which generates a more complete and physiologic lipofuscin model. Described here is a method to induce the accumulation of lipofuscin-like material (termed undigestible autofluorescence material, or UAM) in highly differentiated primary human pre-natal RPE (hfRPE) and induced pluripotent stem cell (iPSC) derived RPE. UAM accumulated in cultures by repeated feedings of ultraviolet light-treated OS fragments taken up by the RPE via phagocytosis. The key ways that UAM approximates and differs from lipofuscin in vivo are also discussed. Accompanying this model of lipofuscin-like accumulation, imaging methods to distinguish the broad autofluorescence spectrum of UAM granules from concurrent antibody staining are introduced. Finally, to assess the impact of UAM on RPE phagocytosis capacity, a new method for quantifying outer segment fragment/tips uptake and breakdown has been introduced. Termed "Total Consumptive Capacity", this method overcomes potential misinterpretations of RPE phagocytosis capacity inherent in classic outer segment "pulse-chase" assays. The models and techniques introduced here can be used to study lipofuscin generation and clearance pathways and putative toxicity.
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Affiliation(s)
- Qitao Zhang
- Kellogg Eye Center, University of Michigan, Ann Arbor
| | | | - Jason M L Miller
- Kellogg Eye Center, University of Michigan, Ann Arbor; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor;
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13
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O-GlcNAcylation regulates phagocytosis by promoting Ezrin localization at the cell cortex. J Genet Genomics 2023:S1673-8527(23)00042-5. [PMID: 36796536 DOI: 10.1016/j.jgg.2023.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 01/25/2023] [Accepted: 02/02/2023] [Indexed: 02/16/2023]
Abstract
O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes. However, it remains uncertain whether O-GlcNAcylation is involved in the regulation of phagocytosis. Here, we demonstrate a rapid increase in protein O-GlcNAcylation in response to phagocytotic stimuli. Knockout of O-GlcNAc transferase or pharmacological inhibition of O-GlcNAcylation dramatically blocks phagocytosis, resulting in the disruption of retinal structure and function. Mechanistic studies reveal that O-GlcNAc transferase interacts with Ezrin, a membrane-cytoskeleton linker protein, to catalyze its O-GlcNAcylation. Our data further show that Ezrin O-GlcNAcylation promotes its localization to the cell cortex, thereby stimulating the membrane-cytoskeleton interaction needed for efficient phagocytosis. These findings identify a previously unrecognized role for protein O-GlcNAcylation in phagocytosis with important implications in both health and diseases.
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14
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Ng ESY, Kady N, Hu J, Dave A, Jiang Z, Pei J, Gorin MB, Matynia A, Radu RA. Membrane Attack Complex Mediates Retinal Pigment Epithelium Cell Death in Stargardt Macular Degeneration. Cells 2022; 11:3462. [PMID: 36359858 PMCID: PMC9655712 DOI: 10.3390/cells11213462] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/28/2022] [Accepted: 10/30/2022] [Indexed: 08/22/2023] Open
Abstract
Recessive Stargardt disease (STGD1) is an inherited retinopathy caused by mutations in the ABCA4 gene. The ABCA4 protein is a phospholipid-retinoid flippase in the outer segments of photoreceptors and the internal membranes of retinal pigment epithelial (RPE) cells. Here, we show that RPE cells derived via induced pluripotent stem-cell from a molecularly and clinically diagnosed STGD1 patient exhibited reduced ABCA4 protein and diminished activity compared to a normal subject. Consequently, STGD1 RPE cells accumulated intracellular autofluorescence-lipofuscin and displayed increased complement C3 activity. The level of C3 inversely correlated with the level of CD46, an early negative regulator of the complement cascade. Persistent complement dysregulation led to deposition of the membrane attack complex on the surface of RPE cells, decrease in transepithelial resistance, and subsequent cell death. These findings are strong evidence of complement-mediated RPE cell damage in STGD1, in the absence of photoreceptors, caused by reduced CD46 regulatory protein.
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Affiliation(s)
- Eunice Sze Yin Ng
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
- Molecular Cellular and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, CA 90095, USA
| | - Nermin Kady
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109, USA
- Clinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Jane Hu
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Arpita Dave
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Zhichun Jiang
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Jacqueline Pei
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Michael B. Gorin
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Anna Matynia
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Roxana A. Radu
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
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15
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Harju N. Regulation of oxidative stress and inflammatory responses in human retinal pigment epithelial cells. Acta Ophthalmol 2022; 100 Suppl 273:3-59. [DOI: 10.1111/aos.15275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Niina Harju
- School of Pharmacy University of Eastern Finland Kuopio Finland
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16
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Moran AL, Fehilly JD, Floss Jones D, Collery R, Kennedy BN. Regulation of the rhythmic diversity of daily photoreceptor outer segment phagocytosis in vivo. FASEB J 2022; 36:e22556. [PMID: 36165194 PMCID: PMC9828801 DOI: 10.1096/fj.202200990rr] [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: 06/28/2022] [Revised: 08/30/2022] [Accepted: 09/06/2022] [Indexed: 01/12/2023]
Abstract
Outer segment phagocytosis (OSP) is a highly-regulated, biological process wherein photoreceptor outer segment (OS) tips are cyclically phagocytosed by the adjacent retinal pigment epithelium (RPE) cells. Often an overlooked retinal process, rhythmic OSP ensures the maintenance of healthy photoreceptors and vision. Daily, the photoreceptors renew OS at their base and the most distal, and likely oldest, OS tips, are phagocytosed by the RPE, preventing the accumulation of photo-oxidative compounds by breaking down phagocytosed OS tips and recycling useful components to the photoreceptors. Light changes often coincide with an escalation of OSP and within hours the phagosomes formed in each RPE cell are resolved. In the last two decades, individual molecular regulators were elucidated. Some of the molecular machinery used by RPE cells for OSP is highly similar to mechanisms used by other phagocytic cells for the clearance of apoptotic cells. Consequently, in the RPE, many molecular regulators of retinal phagocytosis have been elucidated. However, there is still a knowledge gap regarding the key regulators of physiological OSP in vivo between endogenous photoreceptors and the RPE. Understanding the regulation of OSP is of significant clinical interest as age-related macular degeneration (AMD) and inherited retinal diseases (IRD) are linked with altered OSP. Here, we review the in vivo timing of OSP peaks in selected species and focus on the reported in vivo environmental and molecular regulators of OSP.
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Affiliation(s)
- Ailis L. Moran
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland,UCD Conway InstituteUniversity College DublinDublinIreland
| | - John D. Fehilly
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland,UCD Conway InstituteUniversity College DublinDublinIreland
| | - Daniel Floss Jones
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland,UCD Conway InstituteUniversity College DublinDublinIreland
| | - Ross Collery
- Department of Cell Biology, Neurobiology and AnatomyMedical College of WisconsinMilwaukeeWisconsinUSA,Department of Ophthalmology and Visual SciencesMedical College of Wisconsin Eye InstituteMilwaukeeWisconsinUSA
| | - Breandán N. Kennedy
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland,UCD Conway InstituteUniversity College DublinDublinIreland
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17
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Battaglia Parodi M, Bianco L, Arrigo A, Saladino A, Antropoli A, Pina A, Marchese A, Aragona E, Rashid HF, Bandello F. Clinical Correlation Between Optical Coherence Tomography Biomarkers and Retinal Sensitivity in Best Vitelliform Macular Dystrophy. Transl Vis Sci Technol 2022; 11:24. [PMID: 36156730 PMCID: PMC9526372 DOI: 10.1167/tvst.11.9.24] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the clinical and imaging features associated with retinal sensitivity in Best vitelliform macular dystrophy (BVMD). Methods This was a cross-sectional, single-center, observational study. Each patient underwent optical coherence tomography (OCT), near-infrared fundus autofluorescence, and OCT angiography. Macular integrity assessment microperimetry under mesopic conditions was performed to obtain retinal sensitivity thresholds from 68 testing points in the central macula. Structural OCT was used to classify BVMD lesions into four types according to their composition: vitelliform, mixed, subretinal fluid, and atrophy. Multilevel, mixed-effects linear regression was used to determine the factors associated with retinal sensitivity. Results The study included 57 eyes of 30 patients with BVMD, 48 of which (84%) were in a clinical stage. Mean retinal sensitivity varied according to the composition of the lesion: the vitelliform type registering the highest (22 ± 4.1 dB), followed by mixed (18.73 ± 2.7 dB), subretinal fluid (15.68 ± 4.2 dB), and atrophy types (11.85 ± 4.6 dB). The factors most strongly associated with mean retinal sensitivity in BVMD proved to be the OCT lesion type and outer nuclear layer thickness. Conclusions Retinal sensitivity in BVMD is influenced by lesion composition and outer nuclear layer thickness. Further studies with long-term follow-up are warranted to examine retinal sensitivity over time and to validate retinal sensitivity changes as biomarkers for BVMD. Translational Relevance Assessing retinal sensitivity in BVMD provides a new instrument in the clinical characterization of the disease and offers the opportunity to identify imaging biomarkers for use as outcome measures in future clinical trials.
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Affiliation(s)
| | - Lorenzo Bianco
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Arrigo
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Andrea Saladino
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Alessio Antropoli
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Adelaide Pina
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Marchese
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Emanuela Aragona
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Hassan Farah Rashid
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
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18
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NMDA Receptor Antagonists Degrade Lipofuscin via Autophagy in Human Retinal Pigment Epithelial Cells. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58081129. [PMID: 36013596 PMCID: PMC9415004 DOI: 10.3390/medicina58081129] [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: 06/28/2022] [Revised: 08/11/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022]
Abstract
Background and Objectives: Age-related macular degeneration is a slow-progressing disease in which lipofuscin accumulates in the retina, causing inflammation and apoptosis of retinal pigment epithelial (RPE) cells. This study aimed to identify N-methyl-D-aspartate (NMDA) signaling as a novel mechanism for scavenging N-retinylidene-N-retinylethanolamine (A2E), a component of ocular lipofuscin, in human RPE cells. Materials and Methods: A2E degradation assays were performed in ARPE-19 cells using fluorescently labeled A2E. The autophagic activity in ARPE-19 cells was measured upon blue light (BL) exposure, after A2E treatment. Autophagy flux was determined by measuring LC3-II formation using immunoblotting and confocal microscopy. To determine whether autophagy via the NMDA receptor is involved in A2E clearance, ATG5-deficient cells were used. Results: Ro 25-6981, an NR2B-selective NMDA receptor antagonist, effectively cleared A2E. Ro 25-6981 reduced A2E accumulation in the lysosomes of ARPE-19 cells at sub-cytotoxic concentrations, while increasing the formation of LC3-II and decreasing p62 protein levels in a concentration-dependent manner. The autophagic flux monitored by RFP-GFP-LC3 and bafilomycin A1 assays was significantly increased by Ro 25-6981. A2E clearance by Ro 25-6981 was abolished in ATG5-depleted ARPE-19 cells, suggesting that A2E degradation by Ro 25-6981 was mediated by autophagy. Furthermore, treatment with other NMDA receptor antagonists, CP-101,606 and AZD6765, showed similar effects on autophagy activation and A2E degradation in ARPE-19 cells. In contrast, glutamate, an NMDA receptor agonist, exhibited a contrasting effect, suggesting that both the activation of autophagy and the degradation of A2E by Ro 25-6981 in ARPE-19 cells occur through inhibition of the NMDA receptor pathway. Conclusions: This study demonstrates that NMDA receptor antagonists degrade lipofuscin via autophagy in human RPE cells and suggests that NMDA receptor antagonists could be promising new therapeutics for retinal degenerative diseases.
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19
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Lewandowski D, Sander CL, Tworak A, Gao F, Xu Q, Skowronska-Krawczyk D. Dynamic lipid turnover in photoreceptors and retinal pigment epithelium throughout life. Prog Retin Eye Res 2022; 89:101037. [PMID: 34971765 PMCID: PMC10361839 DOI: 10.1016/j.preteyeres.2021.101037] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/13/2022]
Abstract
The retinal pigment epithelium-photoreceptor interphase is renewed each day in a stunning display of cellular interdependence. While photoreceptors use photosensitive pigments to convert light into electrical signals, the RPE supports photoreceptors in their function by phagocytizing shed photoreceptor tips, regulating the blood retina barrier, and modulating inflammatory responses, as well as regenerating the 11-cis-retinal chromophore via the classical visual cycle. These processes involve multiple protein complexes, tightly regulated ligand-receptors interactions, and a plethora of lipids and protein-lipids interactions. The role of lipids in maintaining a healthy interplay between the RPE and photoreceptors has not been fully delineated. In recent years, novel technologies have resulted in major advancements in understanding several facets of this interplay, including the involvement of lipids in phagocytosis and phagolysosome function, nutrient recycling, and the metabolic dependence between the two cell types. In this review, we aim to integrate the complex role of lipids in photoreceptor and RPE function, emphasizing the dynamic exchange between the cells as well as discuss how these processes are affected in aging and retinal diseases.
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Affiliation(s)
- Dominik Lewandowski
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Christopher L Sander
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Fangyuan Gao
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Qianlan Xu
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA.
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20
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Edwards G, Olson CG, Euritt CP, Koulen P. Molecular Mechanisms Underlying the Therapeutic Role of Vitamin E in Age-Related Macular Degeneration. Front Neurosci 2022; 16:890021. [PMID: 35600628 PMCID: PMC9114494 DOI: 10.3389/fnins.2022.890021] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 03/21/2022] [Indexed: 12/31/2022] Open
Abstract
The eye is particularly susceptible to oxidative stress and disruption of the delicate balance between oxygen-derived free radicals and antioxidants leading to many degenerative diseases. Attention has been called to all isoforms of vitamin E, with α-tocopherol being the most common form. Though similar in structure, each is diverse in antioxidant activity. Preclinical reports highlight vitamin E’s influence on cell physiology and survival through several signaling pathways by activating kinases and transcription factors relevant for uptake, transport, metabolism, and cellular action to promote neuroprotective effects. In the clinical setting, population-based studies on vitamin E supplementation have been inconsistent at times and follow-up studies are needed. Nonetheless, vitamin E’s health benefits outweigh the controversies. The goal of this review is to recognize the importance of vitamin E’s role in guarding against gradual central vision loss observed in age-related macular degeneration (AMD). The therapeutic role and molecular mechanisms of vitamin E’s function in the retina, clinical implications, and possible toxicity are collectively described in the present review.
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21
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Moran AL, Carter SP, Kaylor JJ, Jiang Z, Broekman S, Dillon ET, Gómez Sánchez A, Minhas SK, van Wijk E, Radu RA, Travis GH, Carey M, Blacque OE, Kennedy BN. Dawn and dusk peaks of outer segment phagocytosis, and visual cycle function require Rab28. FASEB J 2022; 36:e22309. [PMID: 35471581 PMCID: PMC9322422 DOI: 10.1096/fj.202101897r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/14/2022] [Accepted: 03/29/2022] [Indexed: 12/12/2022]
Abstract
RAB28 is a farnesylated, ciliary G-protein. Patient variants in RAB28 are causative of autosomal recessive cone-rod dystrophy (CRD), an inherited human blindness. In rodent and zebrafish models, the absence of Rab28 results in diminished dawn, photoreceptor, outer segment phagocytosis (OSP). Here, we demonstrate that Rab28 is also required for dusk peaks of OSP, but not for basal OSP levels. This study further elucidated the molecular mechanisms by which Rab28 controls OSP and inherited blindness. Proteomic profiling identified factors whose expression in the eye or whose expression at dawn and dusk peaks of OSP is dysregulated by loss of Rab28. Notably, transgenic overexpression of Rab28, solely in zebrafish cones, rescues the OSP defect in rab28 KO fish, suggesting rab28 gene replacement in cone photoreceptors is sufficient to regulate Rab28-OSP. Rab28 loss also perturbs function of the visual cycle as retinoid levels of 11-cRAL, 11cRP, and atRP are significantly reduced in larval and adult rab28 KO retinae (p < .05). These data give further understanding on the molecular mechanisms of RAB28-associated CRD, highlighting roles of Rab28 in both peaks of OSP, in vitamin A metabolism and in retinoid recycling.
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Affiliation(s)
- Ailís L. Moran
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
| | - Stephen P. Carter
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
| | - Joanna J. Kaylor
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Zhichun Jiang
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Sanne Broekman
- Department of OtorhinolaryngologyRadboud University Medical CenterNijmegenThe Netherlands
- Donders Institute for Brain, Cognition, and BehaviorNijmegenThe Netherlands
| | | | - Alicia Gómez Sánchez
- UCD Conway InstituteUniversity College DublinDublinIreland
- Ocupharm Diagnostic Group ResearchFaculty of Optic and OptometryUniversidad Complutense de MadridMadridSpain
| | - Sajal K. Minhas
- UCD School of Mathematics & StatisticsUniversity College DublinDublinIreland
| | - Erwin van Wijk
- Department of OtorhinolaryngologyRadboud University Medical CenterNijmegenThe Netherlands
- Donders Institute for Brain, Cognition, and BehaviorNijmegenThe Netherlands
| | - Roxana A. Radu
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Gabriel H. Travis
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
- Department of Biological ChemistryUniversity of CaliforniaLos Angeles School of MedicineLos AngelesCaliforniaUSA
| | - Michelle Carey
- UCD School of Mathematics & StatisticsUniversity College DublinDublinIreland
| | - Oliver E. Blacque
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
| | - Breandán N. Kennedy
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
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22
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Fang Y, Taubitz T, Tschulakow AV, Heiduschka P, Szewczyk G, Burnet M, Peters T, Biesemeier A, Sarna T, Schraermeyer U, Julien-Schraermeyer S. Removal of RPE lipofuscin results in rescue from retinal degeneration in a mouse model of advanced Stargardt disease: Role of reactive oxygen species. Free Radic Biol Med 2022; 182:132-149. [PMID: 35219849 DOI: 10.1016/j.freeradbiomed.2022.02.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/17/2022] [Accepted: 02/22/2022] [Indexed: 11/30/2022]
Abstract
Accumulation of lipofuscin in the retinal pigment epithelium (RPE) is a hallmark of aging and is associated with retinal degeneration encountered in age-related macular degeneration (AMD) and Stargardt disease (SD). Currently, treatment for lipofuscin-induced retinal degeneration is unavailable. Here, we report that Remofuscin (INN: soraprazan, a tetrahydropyridoether small molecule) reverses lipofuscin accumulation in aged primary human RPE cells and is non-cytotoxic in aged SD mouse RPE cells in vitro. In addition, we show that the removal of lipofuscin after a single intravitreal injection of Remofuscin results in a rescue from retinal degeneration in a mouse model of advanced SD which is even accompanied by an amelioration of the retinal dysfunction. Finally, we demonstrate that the mechanism causing lipofuscinolysis may involve the reactive oxygen species generated via the presence of Remofuscin. These data suggest a possible therapeutic approach to untreatable lipofuscin-mediated diseases like AMD, SD and lipofuscinopathies in neurodegenerative diseases.
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Affiliation(s)
- Yuan Fang
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Tatjana Taubitz
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Alexander V Tschulakow
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany; STZ Ocutox, Preclinical Drug Assessment, Hechingen, Germany
| | - Peter Heiduschka
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Grzegorz Szewczyk
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | | | - Tobias Peters
- Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Antje Biesemeier
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Ulrich Schraermeyer
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany; STZ Ocutox, Preclinical Drug Assessment, Hechingen, Germany
| | - Sylvie Julien-Schraermeyer
- Division of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany; STZ Ocutox, Preclinical Drug Assessment, Hechingen, Germany.
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23
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Molday RS, Garces FA, Scortecci JF, Molday LL. Structure and function of ABCA4 and its role in the visual cycle and Stargardt macular degeneration. Prog Retin Eye Res 2021; 89:101036. [PMID: 34954332 DOI: 10.1016/j.preteyeres.2021.101036] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/07/2021] [Accepted: 12/13/2021] [Indexed: 12/17/2022]
Abstract
ABCA4 is a member of the superfamily of ATP-binding cassette (ABC) transporters that is preferentially localized along the rim region of rod and cone photoreceptor outer segment disc membranes. It uses the energy from ATP binding and hydrolysis to transport N-retinylidene-phosphatidylethanolamine (N-Ret-PE), the Schiff base adduct of retinal and phosphatidylethanolamine, from the lumen to the cytoplasmic leaflet of disc membranes. This ensures that all-trans-retinal and excess 11-cis-retinal are efficiently cleared from photoreceptor cells thereby preventing the accumulation of toxic retinoid compounds. Loss-of-function mutations in the gene encoding ABCA4 cause autosomal recessive Stargardt macular degeneration, also known as Stargardt disease (STGD1), and related autosomal recessive retinopathies characterized by impaired central vision and an accumulation of lipofuscin and bis-retinoid compounds. High resolution structures of ABCA4 in its substrate and nucleotide free state and containing bound N-Ret-PE or ATP have been determined by cryo-electron microscopy providing insight into the molecular architecture of ABCA4 and mechanisms underlying substrate recognition and conformational changes induced by ATP binding. The expression and functional characterization of a large number of disease-causing missense ABCA4 variants have been determined. These studies have shed light into the molecular mechanisms underlying Stargardt disease and a classification that reliably predicts the effect of a specific missense mutation on the severity of the disease. They also provide a framework for developing rational therapeutic treatments for ABCA4-associated diseases.
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Affiliation(s)
- Robert S Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada; Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, B.C., Canada.
| | - Fabian A Garces
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada
| | | | - Laurie L Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada
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24
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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: 0.5] [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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25
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Relationship between shift work and age-related macular degeneration: a cross-sectional analysis of data from the 5th Korea National Health and Nutrition Examination Survey (2010-2012). Ann Occup Environ Med 2021; 33:e7. [PMID: 34754468 PMCID: PMC7952766 DOI: 10.35371/aoem.2021.33.e7] [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: 08/31/2020] [Accepted: 01/21/2021] [Indexed: 11/20/2022] Open
Abstract
Background Age-related macular degeneration (AMD) is the leading cause of blindness. Shift work has well-known adverse effects on health. However, few studies have investigated the relationship between shift work and AMD. This study was conducted to investigate the relationship between shift work and AMD. Methods This study used aggregated data from the 2010-2012 cycles of the Korea National Health and Nutrition Examination Survey. The work schedules were classified into 2 types: day work and shift work. AMD was determined using fundus photographs. The χ2 test and multiple logistic regression analysis were used to assess sex-stratified relationship between shift work and AMD. Results The odds ratio (OR) of AMD in male shift workers was higher (1.54 [95% confidence interval, CI: 1.01-2.36]) than that in male day workers after adjusting for covariates. After dividing into subgroups of the shift work pattern, the OR of AMD in male night shift workers was higher (1.75 [95% CI: 1.07-2.85]) than that in male day workers after adjusting for covariates. However, results of the female worker group were not significant. Conclusions The results of this study provide limited support for the hypothesis that shift work is related to AMD. Further prospective studies are needed to define the relationship between shift work and AMD.
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Cronin T, Croyal M, Provost N, Ducloyer JB, Mendes-Madeira A, Libeau L, Morival C, Toublanc E, Audrain C, Isiegas C, Pichard V, Adjali O. Effect of retinol dehydrogenase gene transfer in a novel rat model of Stargardt disease. FASEB J 2021; 35:e21934. [PMID: 34599778 DOI: 10.1096/fj.202002525rrr] [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: 11/30/2020] [Revised: 08/25/2021] [Accepted: 09/03/2021] [Indexed: 11/11/2022]
Abstract
Dysfunction of the ATPase-binding Cassette Transporter protein (ABCA4) can lead to early onset macular degeneration, in particular to Stargardt disease. To enable translational research into this form of blindness, we evaluated the effect of Cas9-induced disruptions of the ABCA4 gene to potentially generate new transgenic rat models of the disease. We show that deletion of the short exon preceding the second nucleotide-binding domain is sufficient to drastically knock down protein levels and results in accumulation of retinoid dimers similar to that associated with Stargardt disease. Overexpression of the retinol dehydrogenase enzymes RDH8 and RDH12 can to a limited extent offset the increase in the bisretinoid levels in the Abca4Ex42-/ - KO rats possibly by restricting the time window in which retinal can dimerize before being reduced to retinol. However, in vivo imaging shows that overexpression of RDH8 can induce retinal degeneration. This may be due to the depletion in the outer segment of the cofactor NADPH, needed for RDH function. The translational potential of RDH therapy as well as other Stargardt disease therapies can be tested using the Abca4 knockdown rat model.
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Affiliation(s)
- T Cronin
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | | | - N Provost
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - J B Ducloyer
- Department of Ophthalmology, University Hospital of Nantes, CHU de Nantes, Nantes, France
| | - A Mendes-Madeira
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - L Libeau
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - C Morival
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - E Toublanc
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - C Audrain
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - C Isiegas
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - V Pichard
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
| | - O Adjali
- Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France
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27
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Huang D, Heath Jeffery RC, Aung-Htut MT, McLenachan S, Fletcher S, Wilton SD, Chen FK. Stargardt disease and progress in therapeutic strategies. Ophthalmic Genet 2021; 43:1-26. [PMID: 34455905 DOI: 10.1080/13816810.2021.1966053] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background: Stargardt disease (STGD1) is an autosomal recessive retinal dystrophy due to mutations in ABCA4, characterized by subretinal deposition of lipofuscin-like substances and bilateral centrifugal vision loss. Despite the tremendous progress made in the understanding of STGD1, there are no approved treatments to date. This review examines the challenges in the development of an effective STGD1 therapy.Materials and Methods: A literature review was performed through to June 2021 summarizing the spectrum of retinal phenotypes in STGD1, the molecular biology of ABCA4 protein, the in vivo and in vitro models used to investigate the mechanisms of ABCA4 mutations and current clinical trials.Results: STGD1 phenotypic variability remains an challenge for clinical trial design and patient selection. Pre-clinical development of therapeutic options has been limited by the lack of animal models reflecting the diverse phenotypic spectrum of STDG1. Patient-derived cell lines have facilitated the characterization of splice mutations but the clinical presentation is not always predicted by the effect of specific mutations on retinoid metabolism in cellular models. Current therapies primarily aim to delay vision loss whilst strategies to restore vision are less well developed.Conclusions: STGD1 therapy development can be accelerated by a deeper understanding of genotype-phenotype correlations.
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Affiliation(s)
- Di Huang
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Rachael C Heath Jeffery
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Samuel McLenachan
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia.,Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia
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28
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Arunkumar R, Gorusupudi A, Li B, Blount JD, Nwagbo U, Kim HJ, Sparrow JR, Bernstein PS. Lutein and zeaxanthin reduce A2E and iso-A2E levels and improve visual performance in Abca4 -/-/Bco2 -/- double knockout mice. Exp Eye Res 2021; 209:108680. [PMID: 34161819 PMCID: PMC8595537 DOI: 10.1016/j.exer.2021.108680] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/08/2021] [Accepted: 06/17/2021] [Indexed: 10/21/2022]
Abstract
Accumulation of bisretinoids such as A2E and its isomer iso-A2E is thought to mediate blue light-induced oxidative damage associated with age-related macular degeneration (AMD) and autosomal recessive Stargardt disease (STGD1). We hypothesize that increasing dietary intake of the macular carotenoids lutein and zeaxanthin in individuals at risk of AMD and STGD1 can inhibit the formation of bisretinoids A2E and iso-A2E, which can potentially ameliorate macular degenerative diseases. To study the beneficial effect of macular carotenoids in a retinal degenerative diseases model, we used ATP-binding cassette, sub-family A member 4 (Abca4-/-)/β,β-carotene-9',10'-oxygenase 2 (Bco2-/-) double knockout (KO) mice that accumulate elevated levels of A2E and iso-A2E in the retinal pigment epithelium (RPE) and macular carotenoids in the retina. Abca4-/-/Bco2-/- and Abca4-/- mice were fed a lutein-supplemented chow, zeaxanthin-supplemented chow or placebo chow (~2.6 mg of carotenoid/mouse/day) for three months. Visual function and electroretinography (ERG) were measured after one month and three months of carotenoid supplementation. The lutein and zeaxanthin supplemented Abca4-/-/Bco2-/- mice had significantly lower levels of RPE/choroid A2E and iso-A2E compared to control mice fed with placebo chow and improved visual performance. Carotenoid supplementation in Abca4-/- mice minimally raised retinal carotenoid levels and did not show much difference in bisretinoid levels or visual function compared to the control diet group. There was a statistically significant inverse correlation between carotenoid levels in the retina and A2E and iso-A2E levels in the RPE/choroid. Supplementation with retinal carotenoids, especially zeaxanthin, effectively inhibits bisretinoid formation in a mouse model of STGD1 genetically enhanced to accumulate carotenoids in the retina. These results provide further impetus to pursue oral carotenoids as therapeutic interventions for STGD1 and AMD.
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Affiliation(s)
- Ranganathan Arunkumar
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Aruna Gorusupudi
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Binxing Li
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - J David Blount
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Uzoamaka Nwagbo
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Hye Jin Kim
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Paul S Bernstein
- Department of Ophthalmology and Visual Science, John A. Moran Eye Center, University of Utah, School of Medicine, Salt Lake City, UT, USA.
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29
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Boyer NP, Thompson DA, Koutalos Y. Relative Contributions of All-Trans and 11-Cis Retinal to Formation of Lipofuscin and A2E Accumulating in Mouse Retinal Pigment Epithelium. Invest Ophthalmol Vis Sci 2021; 62:1. [PMID: 33523199 PMCID: PMC7862733 DOI: 10.1167/iovs.62.2.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Bis-retinoids are a major component of lipofuscin that accumulates in the retinal pigment epithelium (RPE) in aging and age-related macular degeneration (AMD). Although bis-retinoids are known to originate from retinaldehydes required for the light response of photoreceptor cells, the relative contributions of the chromophore, 11-cis retinal, and photoisomerization product, all-trans retinal, are unknown. In photoreceptor outer segments, all-trans retinal, but not 11-cis retinal, is reduced by retinol dehydrogenase 8 (RDH8). Using Rdh8−/− mice, we evaluated the contribution of increased all-trans retinal to the formation and stability of RPE lipofuscin. Methods Rdh8−/− mice were reared in cyclic-light or darkness for up to 6 months, with selected light-reared cohorts switched to dark-rearing for the final 1 to 8 weeks. The bis-retinoid A2E was measured from chloroform-methanol extracts of RPE-choroid using HPLC-UV/VIS spectroscopy. Lipofuscin fluorescence was measured from whole flattened eyecups (excitation, 488 nm; emission, 565–725 nm). Results Cyclic-light-reared Rdh8−/− mice accumulated A2E and RPE lipofuscin approximately 1.5 times and approximately 2 times faster, respectively, than dark-reared mice. Moving Rdh8−/− mice from cyclic-light to darkness resulted in A2E levels less than expected to have accumulated before the move. Conclusions Our findings establish that elevated levels of all-trans retinal present in cyclic-light-reared Rdh8−/− mice, which remain low in wild-type mice, contribute only modestly to RPE lipofuscin formation and accumulation. Furthermore, decreases in A2E levels occurring after moving cyclic-light-reared Rdh8−/− mice to darkness are consistent with processing of A2E within the RPE and the existence of a mechanism that could be a therapeutic target for controlling A2E cytotoxicity.
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Affiliation(s)
- Nicholas P Boyer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Debra A Thompson
- Department of Ophthalmology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States.,Department of Biological Chemistry, University of Michigan School of Medicine, Ann Arbor, Michigan, United States
| | - Yiannis Koutalos
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
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30
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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: 2.0] [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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31
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Yeboah GK, Lobanova ES, Brush RS, Agbaga MP. Very long chain fatty acid-containing lipids: a decade of novel insights from the study of ELOVL4. J Lipid Res 2021; 62:100030. [PMID: 33556440 PMCID: PMC8042400 DOI: 10.1016/j.jlr.2021.100030] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 01/12/2021] [Accepted: 01/27/2021] [Indexed: 11/18/2022] Open
Abstract
Lipids play essential roles in maintaining cell structure and function by modulating membrane fluidity and cell signaling. The fatty acid elongase-4 (ELOVL4) protein, expressed in retina, brain, Meibomian glands, skin, testes and sperm, is an essential enzyme that mediates tissue-specific biosynthesis of both VLC-PUFA and VLC-saturated fatty acids (VLC-SFA). These fatty acids play critical roles in maintaining retina and brain function, neuroprotection, skin permeability barrier maintenance, and sperm function, among other important cellular processes. Mutations in ELOVL4 that affect biosynthesis of these fatty acids cause several distinct tissue-specific human disorders that include blindness, age-related cerebellar atrophy and ataxia, skin disorders, early-childhood seizures, mental retardation, and mortality, which underscores the essential roles of ELOVL4 products for life. However, the mechanisms by which one tissue makes VLC-PUFA and another makes VLC-SFA, and how these fatty acids exert their important functional roles in each tissue, remain unknown. This review summarizes research over that last decade that has contributed to our current understanding of the role of ELOVL4 and its products in cellular function. In the retina, VLC-PUFA and their bioactive "Elovanoids" are essential for retinal function. In the brain, VLC-SFA are enriched in synaptic vesicles and mediate neuronal signaling by determining the rate of neurotransmitter release essential for normal neuronal function. These findings point to ELOVL4 and its products as being essential for life. Therefore, mutations and/or age-related epigenetic modifications of fatty acid biosynthetic gene activity that affect VLC-SFA and VLC-PUFA biosynthesis contribute to age-related dysfunction of ELOVL4-expressing tissues.
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Affiliation(s)
- Gyening Kofi Yeboah
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Ekaterina S Lobanova
- Department of Ophthalmology Research, University of Florida, Gainesville, FL, USA
| | - Richard S Brush
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Dean A. McGee Eye Institute, Oklahoma City, OK, USA
| | - Martin-Paul Agbaga
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Dean A. McGee Eye Institute, Oklahoma City, OK, USA.
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32
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Ruan Y, Jiang S, Gericke A. Age-Related Macular Degeneration: Role of Oxidative Stress and Blood Vessels. Int J Mol Sci 2021; 22:ijms22031296. [PMID: 33525498 PMCID: PMC7866075 DOI: 10.3390/ijms22031296] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/25/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is a common irreversible ocular disease characterized by vision impairment among older people. Many risk factors are related to AMD and interact with each other in its pathogenesis. Notably, oxidative stress and choroidal vascular dysfunction were suggested to be critically involved in AMD pathogenesis. In this review, we give an overview on the factors contributing to the pathophysiology of this multifactorial disease and discuss the role of reactive oxygen species and vascular function in more detail. Moreover, we give an overview on therapeutic strategies for patients suffering from AMD.
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Affiliation(s)
- Yue Ruan
- Correspondence: (Y.R.); (A.G.); Tel.: +49-6131-178-276 (Y.R. & A.G.)
| | | | - Adrian Gericke
- Correspondence: (Y.R.); (A.G.); Tel.: +49-6131-178-276 (Y.R. & A.G.)
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33
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Yanık Ö, Demirel S, Batıoğlu F, Özmert E. Natural course of acquired vitelliform lesions associated with pigment epithelial detachments in dry age related macular degeneration. Eur J Ophthalmol 2021; 31:3133-3141. [PMID: 33506698 DOI: 10.1177/1120672121990566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To describe the natural history of acquired vitelliform lesions (AVLs) associated with different types of pigment epithelial detachments (PEDs) in dry age-related macular degeneration. METHODS A retrospective review of clinical examination and multimodal imaging data of patients with AVLs associated with PED(s) was performed. RESULTS This study included 25 eyes of 17 patients. The mean age of patients was 67.2 ± 9.7 (47-83) years. The mean follow-up time was 32.6 ± 16.2 (12-66) months, excluding four patients (five eyes) that were lost to follow-up. The mean logMAR BCVA was 0.21 ± 0.16 at baseline and 0.38 ± 0.28 at final visit (p = 0.016). At the end of the follow-up period, PEDs enlarged in eight eyes (40%) and were unchanged in two eyes (10%). Spontaneous resolution of the central PED(s) with AVLs was seen in four (20%) eyes. Rupture of the PED(s) occurred in four eyes (20%), with two developing central foveolar atrophy afterwards. Overall, central foveolar atrophy was seen ultimately in four eyes (20%). CONCLUSION It seems that high PED size may be a risk factor for PED rupture during follow-up. 1/3 of the eyes ended up with unfavorable anatomical outcome.
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Affiliation(s)
- Özge Yanık
- Department of Ophthalmology, Ankara University School of Medicine, Ankara, Turkey
| | - Sibel Demirel
- Department of Ophthalmology, Ankara University School of Medicine, Ankara, Turkey
| | - Figen Batıoğlu
- Department of Ophthalmology, Ankara University School of Medicine, Ankara, Turkey
| | - Emin Özmert
- Department of Ophthalmology, Ankara University School of Medicine, Ankara, Turkey
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34
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Pugazhendhi A, Hubbell M, Jairam P, Ambati B. Neovascular Macular Degeneration: A Review of Etiology, Risk Factors, and Recent Advances in Research and Therapy. Int J Mol Sci 2021; 22:1170. [PMID: 33504013 PMCID: PMC7866170 DOI: 10.3390/ijms22031170] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/11/2021] [Accepted: 01/19/2021] [Indexed: 12/14/2022] Open
Abstract
Neovascular age-related macular degeneration (exudative or wet AMD) is a prevalent, progressive retinal degenerative macular disease that is characterized by neovascularization of the choroid, mainly affecting the elderly population causing gradual vision impairment. Risk factors such as age, race, genetics, iris color, smoking, drinking, BMI, and diet all play a part in nvAMD's progression, with anti-vascular endothelial growth factor (anti-VEGF) therapy being the mainstay of treatment. Current therapeutic advancements slow the progression of the disease but do not cure or reverse its course. Newer therapies such as gene therapies, Rho-kinase inhibitors, and levodopa offer potential new targets for treatment.
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Affiliation(s)
- Arunbalaji Pugazhendhi
- Knights Campus for Accelerating Scientific Impact, University of Oregon, Eugene, OR 97403, USA; (A.P.); (M.H.)
| | - Margaret Hubbell
- Knights Campus for Accelerating Scientific Impact, University of Oregon, Eugene, OR 97403, USA; (A.P.); (M.H.)
| | - Pooja Jairam
- Vagelos College of Physicians & Surgeons, Columbia Irving Medical Center, Columbia University, New York, NY 10032, USA;
| | - Balamurali Ambati
- Knights Campus for Accelerating Scientific Impact, University of Oregon, Eugene, OR 97403, USA; (A.P.); (M.H.)
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35
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Tosi GM, Giustarini D, Franci L, Minetti A, Imperatore F, Caldi E, Fiorenzani P, Aloisi AM, Sparatore A, Rossi R, Chiariello M, Orlandini M, Galvagni F. Superior Properties of N-Acetylcysteine Ethyl Ester over N-Acetyl Cysteine to Prevent Retinal Pigment Epithelial Cells Oxidative Damage. Int J Mol Sci 2021; 22:E600. [PMID: 33435325 PMCID: PMC7827200 DOI: 10.3390/ijms22020600] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/28/2020] [Accepted: 01/06/2021] [Indexed: 12/20/2022] Open
Abstract
Oxidative stress plays a key role in the pathophysiology of retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy, which are the major causes of irreversible blindness in developed countries. An excess of reactive oxygen species (ROS) can directly cause functional and morphological impairments in retinal pigment epithelium (RPE), endothelial cells, and retinal ganglion cells. Antioxidants may represent a preventive/therapeutic strategy and reduce the risk of progression of AMD. Among antioxidants, N-acetyl-L-cysteine (NAC) is widely studied and has been proposed to have therapeutic benefit in treating AMD by mitigating oxidative damage in RPE. Here, we demonstrate that N-acetyl-L-cysteine ethyl ester (NACET), a lipophilic cell-permeable cysteine derivative, increases the viability in oxidative stressed RPE cells more efficiently than NAC by reacting directly and more rapidly with oxidizing agents, and that NACET, but not NAC, pretreatment predisposes RPE cells to oxidative stress resistance and increases the intracellular reduced glutathione (GSH) pool available to act as natural antioxidant defense. Moreover, we demonstrate the ability of NACET to increase GSH levels in rats' eyes after oral administration. In conclusion, even if experiments in AMD animal models are still needed, our data suggest that NACET may play an important role in preventing and treating retinal diseases associated with oxidative stress, and may represent a valid and more efficient alternative to NAC in therapeutic protocols in which NAC has already shown promising results.
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Affiliation(s)
- Gian Marco Tosi
- Ophthalmology Unit of the Department of Medicine, Surgery and Neuroscience, University of Siena, 53100 Siena, Italy;
| | - Daniela Giustarini
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy; (D.G.); (A.M.); (E.C.); (R.R.)
| | - Lorenzo Franci
- Core Research Laboratory, Istituto per lo Studio, la Prevenzione e la Rete Oncologica (ISPRO), 53100 Siena, Italy; (L.F.); (F.I.); (M.C.)
- Istituto di Fisiologia Clinica, Consiglio Nazionale delle Ricerche, 53100 Siena, Italy
| | - Alberto Minetti
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy; (D.G.); (A.M.); (E.C.); (R.R.)
| | - Francesco Imperatore
- Core Research Laboratory, Istituto per lo Studio, la Prevenzione e la Rete Oncologica (ISPRO), 53100 Siena, Italy; (L.F.); (F.I.); (M.C.)
- Istituto di Fisiologia Clinica, Consiglio Nazionale delle Ricerche, 53100 Siena, Italy
| | - Elena Caldi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy; (D.G.); (A.M.); (E.C.); (R.R.)
| | - Paolo Fiorenzani
- Department of Medicine, Surgery and Neuroscience, University of Siena, 53100 Siena, Italy; (P.F.); (A.M.A.)
| | - Anna Maria Aloisi
- Department of Medicine, Surgery and Neuroscience, University of Siena, 53100 Siena, Italy; (P.F.); (A.M.A.)
| | - Anna Sparatore
- Department of Pharmaceutical Sciences, University of Milan, 20133 Milan, Italy;
| | - Ranieri Rossi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy; (D.G.); (A.M.); (E.C.); (R.R.)
| | - Mario Chiariello
- Core Research Laboratory, Istituto per lo Studio, la Prevenzione e la Rete Oncologica (ISPRO), 53100 Siena, Italy; (L.F.); (F.I.); (M.C.)
- Istituto di Fisiologia Clinica, Consiglio Nazionale delle Ricerche, 53100 Siena, Italy
| | - Maurizio Orlandini
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy; (D.G.); (A.M.); (E.C.); (R.R.)
| | - Federico Galvagni
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy; (D.G.); (A.M.); (E.C.); (R.R.)
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Kutsyr O, Sánchez-Sáez X, Martínez-Gil N, de Juan E, Lax P, Maneu V, Cuenca N. Gradual Increase in Environmental Light Intensity Induces Oxidative Stress and Inflammation and Accelerates Retinal Neurodegeneration. Invest Ophthalmol Vis Sci 2021; 61:1. [PMID: 32744596 PMCID: PMC7441298 DOI: 10.1167/iovs.61.10.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose Retinitis pigmentosa (RP) is a blinding neurodegenerative disease of the retina that can be affected by many factors. The present study aimed to analyze the effect of different environmental light intensities in rd10 mice retina. Methods C57BL/6J and rd10 mice were bred and housed under three different environmental light intensities: scotopic (5 lux), mesopic (50 lux), and photopic (300 lux). Visual function was studied using electroretinography and optomotor testing. The structural and morphological integrity of the retinas was evaluated by optical coherence tomography imaging and immunohistochemistry. Additionally, inflammatory processes and oxidative stress markers were analyzed by flow cytometry and western blotting. Results When the environmental light intensity was higher, retinal function decreased in rd10 mice and was accompanied by light-dependent photoreceptor loss, followed by morphological alterations, and synaptic connectivity loss. Moreover, light-dependent retinal degeneration was accompanied by an increased number of inflammatory cells, which became more activated and phagocytic, and by an exacerbated reactive gliosis. Furthermore, light-dependent increment in oxidative stress markers in rd10 mice retina pointed to a possible mechanism for light-induced photoreceptor degeneration. Conclusions An increase in rd10 mice housing light intensity accelerates retinal degeneration, activating cell death, oxidative stress pathways, and inflammatory cells. Lighting intensity is a key factor in the progression of retinal degeneration, and standardized lighting conditions are advisable for proper analysis and interpretation of experimental results from RP animal models, and specifically from rd10 mice. Also, it can be hypothesized that light protection could be an option to slow down retinal degeneration in some cases of RP.
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Evidence of complement dysregulation in outer retina of Stargardt disease donor eyes. Redox Biol 2020; 37:101787. [PMID: 33214125 PMCID: PMC7767765 DOI: 10.1016/j.redox.2020.101787] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 01/24/2023] Open
Abstract
Stargardt macular degeneration (STGD) is a central blinding disease caused by loss of or dysfunctional ABCA4 transporter in both photoreceptors and retinal pigment epithelial (RPE) cells. Toxic bisretinoid-lipofuscin buildup in the RPE cells is a pathological hallmark of STGD patients and its mouse model, the Abca4-/-. These vitamin A-derived fluorophores have been shown to induce oxidative stress, stimulate complement activity, and cause chronic inflammation of the RPE. In vivo modulation of complement regulatory pathway in the STGD mouse model has partially rescued the STGD phenotype suggesting that complement attack on the RPE is an important etiologic factor in disease pathogenesis. While bisretinoid-dependent complement activation was further evidenced in cultured RPE cells, this pathway has never been investigated directly in the context of RPE from STGD donor eyes. In the current study, we evaluate the complement reactivity in postmortem donor eyes of clinically diagnosed STGD patients. All three STGD donor eyes RPE displayed strong immunoreactivity for an antibody specific to 4-Hydroxynonenal, a lipid peroxidation byproduct. Also, unlike the control eyes, all three STGD donor eyes showed significantly increased membrane attack complex deposition on the RPE cells. In STGD eyes, increased MAC accumulation was mirrored by elevated C3 fragments internalized by the RPE and inversely correlated with the levels of complement factor H, a major complement regulatory protein. Here, we report the first direct evidence of RPE complement dysregulation as a causative factor in developing Stargardt phenotype.
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Parmar T, Ortega JT, Jastrzebska B. Retinoid analogs and polyphenols as potential therapeutics for age-related macular degeneration. Exp Biol Med (Maywood) 2020; 245:1615-1625. [PMID: 32438835 PMCID: PMC7787542 DOI: 10.1177/1535370220926938] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
IMPACT STATEMENT Age-related macular degeneration (AMD) is a devastating retinal degenerative disease. Epidemiological reports showed an expected increasing prevalence of AMD in the near future. The only one existing FDA-approved pharmacological treatment involves an anti-vascular endothelial growth factor (VEGF) therapy with serious disadvantages. This limitation emphasizes an alarming need to develop new therapeutic approaches to prevent and treat AMD. In this review, we summarize scientific data unraveling the therapeutic potential of the specific retinoid and natural compounds. The experimental results reported by us and other research groups demonstrated that retinoid analogs and compounds with natural product scaffolds could serve as lead compounds for the development of new therapeutic agents with potential to prevent or slow down the pathogenesis of AMD.
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Affiliation(s)
- Tanu Parmar
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Joseph T Ortega
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Beata Jastrzebska
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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Streeter MD, Rowan S, Ray J, McDonald DM, Volkin J, Clark J, Taylor A, Spiegel DA. Generation and Characterization of Anti-Glucosepane Antibodies Enabling Direct Detection of Glucosepane in Retinal Tissue. ACS Chem Biol 2020; 15:2655-2661. [PMID: 32975399 PMCID: PMC10625846 DOI: 10.1021/acschembio.0c00093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Although there is ample evidence that the advanced glycation end-product (AGE) glucosepane contributes to age-related morbidities and diabetic complications, the impact of glucosepane modifications on proteins has not been extensively explored due to the lack of sufficient analytical tools. Here, we report the development of the first polyclonal anti-glucosepane antibodies using a synthetic immunogen that contains the core bicyclic ring structure of glucosepane. We investigate the recognition properties of these antibodies through ELISAs involving an array of synthetic AGE derivatives and determine them to be both high-affinity and selective in binding glucosepane. We then employ these antibodies to image glucosepane in aging mouse retinae via immunohistochemistry. Our studies demonstrate for the first time accumulation of glucosepane within the retinal pigment epithelium, Bruch's membrane, and choroid: all regions of the eye impacted by age-related macular degeneration. Co-localization studies further suggest that glucosepane colocalizes with lipofuscin, which has previously been associated with lysosomal dysfunction and has been implicated in the development of age-related macular degeneration, among other diseases. We believe that the anti-glucosepane antibodies described in this study will prove highly useful for examining the role of glycation in human health and disease.
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Affiliation(s)
- Matthew D Streeter
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - Sheldon Rowan
- Tufts University, JM-USDA Human Nutrition Research Center on Aging, 711 Washington Street, Boston, Massachusetts 02111, United States
| | - Jason Ray
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - David M McDonald
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - Jonathan Volkin
- Tufts University, JM-USDA Human Nutrition Research Center on Aging, 711 Washington Street, Boston, Massachusetts 02111, United States
| | - Jonathan Clark
- Biological Chemistry Laboratory, Babraham Institute, Cambridge CB21 3AT, United Kingdom
| | - Allen Taylor
- Tufts University, JM-USDA Human Nutrition Research Center on Aging, 711 Washington Street, Boston, Massachusetts 02111, United States
| | - David A Spiegel
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, United States
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An In-Vitro Cell Model of Intracellular Protein Aggregation Provides Insights into RPE Stress Associated with Retinopathy. Int J Mol Sci 2020; 21:ijms21186647. [PMID: 32932802 PMCID: PMC7555953 DOI: 10.3390/ijms21186647] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/30/2020] [Accepted: 09/07/2020] [Indexed: 12/11/2022] Open
Abstract
Impaired cargo trafficking and the aggregation of intracellular macromolecules are key features of neurodegeneration, and a hallmark of aged as well as diseased retinal pigment epithelial (RPE) cells in the eye. Here, photoreceptor outer segments (POS), which are internalized daily by RPE cells, were modified by UV-irradiation to create oxidatively modified POS (OxPOS). Oxidative modification was quantified by a protein carbonyl content assay. Human ARPE-19 cells were synchronously pulsed with POS or OxPOS to study whether oxidatively modified cargos can recapitulate features of RPE pathology associated with blinding diseases. Confocal immunofluorescence microscopy analysis showed that OxPOS was trafficked to LAMP1, LAMP2 lysosomes and to LC3b autophagy vacuoles. Whilst POS were eventually degraded, OxPOS cargos were sequestered in late compartments. Co-localization of OxPOS was also associated with swollen autolysosomes. Ultrastructural analysis revealed the presence of electron-dense OxPOS aggregates in RPE cells, which appeared to be largely resistant to degradation. Measurement of cellular autofluorescence, using parameters used to assess fundus autofluorescence (FAF) in age-related macular disease (AMD) patients, revealed that OxPOS contributed significantly to a key feature of aged and diseased RPE. This in vitro cell model therefore represents a versatile tool to study disease pathways linked with RPE damage and sight-loss.
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Cioffi CL, Muthuraman P, Raja A, Varadi A, Racz B, Petrukhin K. Discovery of Bispecific Antagonists of Retinol Binding Protein 4 That Stabilize Transthyretin Tetramers: Scaffolding Hopping, Optimization, and Preclinical Pharmacological Evaluation as a Potential Therapy for Two Common Age-Related Comorbidities. J Med Chem 2020; 63:11054-11084. [DOI: 10.1021/acs.jmedchem.0c00996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Christopher L. Cioffi
- Departments of Basic and Clinical Sciences and Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, 106 New Scotland Avenue, Albany, New York 12208, United States
| | - Parthasarathy Muthuraman
- Departments of Basic and Clinical Sciences and Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, 106 New Scotland Avenue, Albany, New York 12208, United States
| | - Arun Raja
- Departments of Basic and Clinical Sciences and Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, 106 New Scotland Avenue, Albany, New York 12208, United States
| | - Andras Varadi
- Department of Ophthalmology, Columbia University Medical Center, New York, New York 10032, United States
| | - Boglarka Racz
- Department of Ophthalmology, Columbia University Medical Center, New York, New York 10032, United States
| | - Konstantin Petrukhin
- Department of Ophthalmology, Columbia University Medical Center, New York, New York 10032, United States
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Sundaramurthi H, Roche SL, Grice GL, Moran A, Dillion ET, Campiani G, Nathan JA, Kennedy BN. Selective Histone Deacetylase 6 Inhibitors Restore Cone Photoreceptor Vision or Outer Segment Morphology in Zebrafish and Mouse Models of Retinal Blindness. Front Cell Dev Biol 2020; 8:689. [PMID: 32984302 PMCID: PMC7479070 DOI: 10.3389/fcell.2020.00689] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/07/2020] [Indexed: 12/19/2022] Open
Abstract
Blindness arising from retinal or macular degeneration results in significant social, health and economic burden. While approved treatments exist for neovascular (‘wet’) age-related macular degeneration, new therapeutic targets/interventions are needed for the more prevalent atrophic (‘dry’) form of age-related macular degeneration. Similarly, in inherited retinal diseases, most patients have no access to an effective treatment. Although macular and retinal degenerations are genetically and clinically distinct, common pathological hallmarks can include photoreceptor degeneration, retinal pigment epithelium atrophy, oxidative stress, hypoxia and defective autophagy. Here, we evaluated the potential of selective histone deacetylase 6 inhibitors to preserve retinal morphology or restore vision in zebrafish atp6v0e1–/– and mouse rd10 models. Histone deacetylase 6 inhibitor, tubastatin A-treated atp6v0e1–/– zebrafish show marked improvement in photoreceptor outer segment area (44.7%, p = 0.027) and significant improvement in vision (8-fold, p ≤ 0.0001). Tubastatin A-treated rd10/rd10 retinal explants show a significantly (p = 0.016) increased number of outer-segment labeled cone photoreceptors. In vitro, ATP6V0E1 regulated HIF-1α activity, but significant regulation of HIF-1α by histone deacetylase 6 inhibition in the retina was not detected. Proteomic profiling identified ubiquitin-proteasome, phototransduction, metabolism and phagosome as pathways, whose altered expression correlated with histone deacetylase 6 inhibitor mediated restoration of vision.
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Affiliation(s)
- Husvinee Sundaramurthi
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.,Systems Biology Ireland, University College Dublin, Dublin, Ireland.,UCD School of Medicine, University College Dublin, Dublin, Ireland
| | - Sarah L Roche
- School of Biochemistry, University College Cork, Cork, Ireland
| | - Guinevere L Grice
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge, Cambridge, United Kingdom
| | - Ailis Moran
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Eugene T Dillion
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.,Mass Spectrometry Resource, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Giuseppe Campiani
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence, University of Siena, Siena, Italy
| | - James A Nathan
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge, Cambridge, United Kingdom
| | - Breandán N Kennedy
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
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Kim DH, Choi YR, Shim J, Choi YS, Kim YT, Kim MK, Kim MJ. Suppressive Effect of Arctium Lappa L. Leaves on Retinal Damage Against A2E-Induced ARPE-19 Cells and Mice. Molecules 2020; 25:molecules25071737. [PMID: 32283798 PMCID: PMC7180975 DOI: 10.3390/molecules25071737] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/04/2020] [Accepted: 04/08/2020] [Indexed: 01/09/2023] Open
Abstract
Age-related macular degeneration (AMD) is a major cause of irreversible loss of vision with 80–90% of patients demonstrating dry type AMD. Dry AMD could possibly be prevented by polyphenol-rich medicinal foods by the inhibition of N-retinylidene-N-retinylethanolamine (A2E)-induced oxidative stress and cell damage. Arctium lappa L. (AL) leaves are medicinal and have antioxidant activity. The purpose of this study was to elucidate the protective effects of the extract of AL leaves (ALE) on dry AMD models, including in vitro A2E-induced damage in ARPE-19 cells, a human retinal pigment epithelial cell line, and in vivo light-induced retinal damage in BALB/c mice. According to the total phenolic contents (TPCs), total flavonoid contents (TFCs) and antioxidant activities, ALE was rich in polyphenols and had antioxidant efficacies on 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and 2′,7′-dichlorofluorescin diacetate (DCFDA) assays. The effects of ALE on A2E accumulation and A2E-induced cell death were also monitored. Despite continued exposure to A2E (10 μM), ALE attenuated A2E accumulation in APRE-19 cells with levels similar to lutein. A2E-induced cell death at high concentration (25 μM) was also suppressed by ALE by inhibiting the apoptotic signaling pathway. Furthermore, ALE could protect the outer nuclear layer (ONL) in the retina from light-induced AMD in BALB/c mice. In conclusion, ALE could be considered a potentially valuable medicinal food for dry AMD.
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Affiliation(s)
- Dong Hee Kim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
- Department of Food Science and Human Nutrition, Jeonbuk National University, Jeonju-si 54896, Korea;
| | - Yae Rim Choi
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
- Department of Food Science and Engineering, Ewha Womans University, Seoul 03760, Korea
| | - Jaewon Shim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
| | - Yun-Sang Choi
- Research Division of Strategic Food Technology, Korea Food Research Institute, Wanju 55365, Korea;
| | - Yun Tai Kim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
- Department of Food Biotechnology, Korea University of Science & Technology, Daejeon 34113, Korea
| | - Mina Kyungmin Kim
- Department of Food Science and Human Nutrition, Jeonbuk National University, Jeonju-si 54896, Korea;
| | - Min Jung Kim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
- Correspondence: ; Tel.: +82-63-219-9380
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Fontaine V, Monteiro E, Fournié M, Brazhnikova E, Boumedine T, Vidal C, Balducci C, Guibout L, Latil M, Dilda PJ, Veillet S, Sahel JA, Lafont R, Camelo S. Systemic administration of the di-apocarotenoid norbixin (BIO201) is neuroprotective, preserves photoreceptor function and inhibits A2E and lipofuscin accumulation in animal models of age-related macular degeneration and Stargardt disease. Aging (Albany NY) 2020; 12:6151-6171. [PMID: 32255762 PMCID: PMC7185133 DOI: 10.18632/aging.103014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/02/2020] [Indexed: 12/31/2022]
Abstract
Atrophic A\age-related macular degeneration (AMD) and Stargardt disease (STGD) are major blinding diseases affecting millions of patients worldwide, but no treatment is available. In dry AMD and STGD oxidative stress and subretinal accumulation of N-retinylidene-N-retinylethanolamine (A2E), a toxic by-product of the visual cycle, causes retinal pigment epithelium (RPE) and photoreceptor degeneration leading to visual impairment. Acute and chronic retinal degeneration following blue light damage (BLD) in BALB/c mice and aging of Abca4-/- Rdh8-/- mice, respectively, reproduce features of AMD and STGD. Efficacy of systemic administrations of 9'-cis-norbixin (norbixin), a natural di-apocarotenoid, prepared from Bixa orellana seeds with anti-oxidative properties, was evaluated during BLD in BALB/c mice, and in Abca4-/- Rdh8-/- mice of different ages, following three experimental designs: “preventive”, “early curative” and “late curative” supplementations. Norbixin injected intraperitoneally in BALB/c mice, maintained scotopic and photopic electroretinogram amplitude and was neuroprotective. Norbixin chronic oral administration for 6 months in Abca4-/- Rdh8-/- mice following the “early curative” supplementation showed optimal neuroprotection and maintenance of photoreceptor function and reduced ocular A2E accumulation. Thus, norbixin appears promising as a systemic drug candidate for both AMD and STGD treatment.
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Affiliation(s)
- Valérie Fontaine
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - Elodie Monteiro
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - Mylène Fournié
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - Elena Brazhnikova
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | | | - Cécile Vidal
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - Christine Balducci
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Louis Guibout
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Mathilde Latil
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Pierre J Dilda
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Stanislas Veillet
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris 75012, France
| | - René Lafont
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
| | - Serge Camelo
- Biophytis, Sorbonne Université, Campus Pierre and Marie Curie, Paris 75005, France
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Fang Y, Tschulakow A, Taubitz T, Illing B, Biesemeier A, Julien-Schraermeyer S, Radu RA, Jiang Z, Schraermeyer U. Fundus autofluorescence, spectral-domain optical coherence tomography, and histology correlations in a Stargardt disease mouse model. FASEB J 2020; 34:3693-3714. [PMID: 31989709 DOI: 10.1096/fj.201901784rr] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 12/17/2019] [Accepted: 12/17/2019] [Indexed: 01/09/2023]
Abstract
Stargardt disease (STGD1), known as inherited retinal dystrophy, is caused by ABCA4 mutations. The pigmented Abca4-/- mouse strain only reflects the early stage of STGD1 since it is devoid of retinal degeneration. This blue light-illuminated pigmented Abca4-/- mouse model presented retinal pigment epithelium (RPE) and photoreceptor degeneration which was similar to the advanced STGD1 phenotype. In contrast, wild-type mice showed no RPE degeneration after blue light illumination. In Abca4-/- mice, the acute blue light diminished the mean autofluorescence (AF) intensity in both fundus short-wavelength autofluorescence (SW-AF) and near-infrared autofluorescence (NIR-AF) modalities correlating with reduced levels of bisretinoid-fluorophores. Blue light-induced RPE cellular damage preceded the photoreceptors loss. In late-stage STGD1-like patient and blue light-illuminated Abca4-/- mice, lipofuscin and melanolipofuscin granules were found to contribute to NIR-AF, indicated by the colocalization of lipofuscin-AF and NIR-AF under the fluorescence microscope. In this mouse model, the correlation between in vivo and ex vivo assessments revealed histological characteristics of fundus AF abnormalities. The flecks which are hyper AF in both SW-AF and NIR-AF corresponded to the subretinal macrophages fully packed with pigment granules (lipofuscin, melanin, and melanolipofuscin). This mouse model, which has the phenotype of advanced STGD1, is important to understand the histopathology of Stargardt disease.
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Affiliation(s)
- Yuan Fang
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Alexander Tschulakow
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Preclinical Drug Assessment, STZ Ocutox, Hechingen, Germany
| | - Tatjana Taubitz
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Barbara Illing
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Antje Biesemeier
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Sylvie Julien-Schraermeyer
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Preclinical Drug Assessment, STZ Ocutox, Hechingen, Germany
| | - Roxana A Radu
- UCLA Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Zhichun Jiang
- UCLA Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Ulrich Schraermeyer
- Division of Experimental Vitreoretinal Surgery, Center for Ophthalmology, Institute of Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Preclinical Drug Assessment, STZ Ocutox, Hechingen, Germany
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Abokyi S, To CH, Lam TT, Tse DY. Central Role of Oxidative Stress in Age-Related Macular Degeneration: Evidence from a Review of the Molecular Mechanisms and Animal Models. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:7901270. [PMID: 32104539 PMCID: PMC7035553 DOI: 10.1155/2020/7901270] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 01/18/2020] [Indexed: 11/17/2022]
Abstract
Age-related macular degeneration (AMD) is a common cause of visual impairment in the elderly. There are very limited therapeutic options for AMD with the predominant therapies targeting vascular endothelial growth factor (VEGF) in the retina of patients afflicted with wet AMD. Hence, it is important to remind readers, especially those interested in AMD, about current studies that may help to develop novel therapies for other stages of AMD. This study, therefore, provides a comprehensive review of studies on human specimens as well as rodent models of the disease, to identify and analyze the molecular mechanisms behind AMD development and progression. The evaluation of this information highlights the central role that oxidative damage in the retina plays in contributing to major pathways, including inflammation and angiogenesis, found in the AMD phenotype. Following on the debate of oxidative stress as the earliest injury in the AMD pathogenesis, we demonstrated how the targeting of oxidative stress-associated pathways, such as autophagy and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling, might be the futuristic direction to explore in the search of an effective treatment for AMD, as the dysregulation of these mechanisms is crucial to oxidative injury in the retina. In addition, animal models of AMD have been discussed in great detail, with their strengths and pitfalls included, to assist inform in the selection of suitable models for investigating any of the molecular mechanisms.
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Affiliation(s)
- Samuel Abokyi
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
- Department of Optometry, University of Cape Coast, Ghana
| | - Chi-Ho To
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
| | - Tim T. Lam
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
| | - Dennis Y. Tse
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
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Keeling E, Chatelet DS, Johnston DA, Page A, Tumbarello DA, Lotery AJ, Ratnayaka JA. Oxidative Stress and Dysfunctional Intracellular Traffic Linked to an Unhealthy Diet Results in Impaired Cargo Transport in the Retinal Pigment Epithelium (RPE). Mol Nutr Food Res 2019; 63:e1800951. [PMID: 30835933 DOI: 10.1002/mnfr.201800951] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/18/2019] [Indexed: 12/19/2022]
Abstract
SCOPE Oxidative stress and dysregulated intracellular trafficking are associated with an unhealthy diet which underlies pathology. Here, these effects on photoreceptor outer segment (POS) trafficking in the retinal pigment epithelium (RPE), a major pathway of disease underlying irreversible sight-loss, are studied. METHODS AND RESULTS POS trafficking is studied in ARPE-19 cells using an algorithm-based quantification of confocal-immunofluorescence data supported by ultrastructural studies. It is shown that although POS are tightly regulated and trafficked via Rab5, Rab7 vesicles, LAMP1/2 lysosomes and LC3b-autophagosomes, there is also a considerable degree of variation and flexibility in this process. Treatment with H2 O2 and bafilomycin A1 reveals that oxidative stress and dysregulated autophagy target intracellular compartments and trafficking in strikingly different ways. These effects appear limited to POS-containing vesicles, suggesting a cargo-specific effect. CONCLUSION The findings offer insights into how RPE cells cope with stress, and how mechanisms influencing POS transport/degradation can have different outcomes in the senescent retina. These shed new light on cellular processes underlying retinopathies such as age-related macular degeneration. The discoveries reveal how diet and nutrition can cause fundamental alterations at a cellular level, thus contributing to a better understanding of the diet-disease axis.
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Affiliation(s)
- Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
| | - David S Chatelet
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - David A Johnston
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - David A Tumbarello
- Biological Sciences, Faculty of Natural & Environmental Sciences, University of Southampton, Life Sciences Building 85, SO17 1BJ, UK
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
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Lu W, Campagno KE, Tso HY, Cenaj A, Laties AM, Carlsson LG, Mitchell CH. Oral Delivery of the P2Y12 Receptor Antagonist Ticagrelor Prevents Loss of Photoreceptors in an ABCA4-/- Mouse Model of Retinal Degeneration. Invest Ophthalmol Vis Sci 2019; 60:3046-3053. [PMID: 31319418 PMCID: PMC6640265 DOI: 10.1167/iovs.19-27241] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/10/2019] [Indexed: 01/22/2023] Open
Abstract
Purpose Accumulation of lysosomal waste is linked to neurodegeneration in multiple diseases, and pharmacologic enhancement of lysosomal activity is hypothesized to reduce pathology. An excessive accumulation of lysosomal-associated lipofuscin waste and an elevated lysosomal pH occur in retinal pigment epithelial cells of the ABCA4-/- mouse model of Stargardt's retinal degeneration. As treatment with the P2Y12 receptor antagonist ticagrelor was previously shown to lower lysosomal pH and lipofuscin-like autofluorescence in these cells, we asked whether oral delivery of ticagrelor also prevented photoreceptor loss. Methods Moderate light exposure was used to accelerate photoreceptor loss in albino ABCA4-/- mice as compared to BALB/c controls. Ticagrelor (0.1%-0.15%) was added to mouse chow for between 1 and 10 months. Photoreceptor function was determined with electroretinograms, while cell survival was determined using optical coherence tomography and histology. Results Protection by ticagrelor was demonstrated functionally by using the electroretinogram, as ticagrelor-treated ABCA4-/- mice had increased a- and b-waves compared to untreated mice. Mice receiving ticagrelor treatment had a thicker outer nuclear layer, as measured with both optical coherence tomography and histologic sections. Ticagrelor decreased expression of LAMP1, implicating enhanced lysosomal function. No signs of retinal bleeding were observed after prolonged treatment with ticagrelor. Conclusions Oral treatment with ticagrelor protected photoreceptors in the ABCA4-/- mouse, which is consistent with enhanced lysosomal function. As mouse ticagrelor exposure levels were clinically relevant, the drug may be of benefit in preventing the loss of photoreceptors in Stargardt's disease and other neurodegenerations associated with lysosomal dysfunction.
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Affiliation(s)
- Wennan Lu
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Keith E. Campagno
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Huen-Yee Tso
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Aurora Cenaj
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alan M. Laties
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Leif G. Carlsson
- Bioscience Cardiovascular Research and Early Development Cardiovascular, Renal and Metabolism BioPhamaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Claire H. Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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49
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RAD51B (rs8017304 and rs2588809), TRIB1 (rs6987702, rs4351379, and rs4351376), COL8A1 (rs13095226), and COL10A1 (rs1064583) Gene Variants with Predisposition to Age-Related Macular Degeneration. DISEASE MARKERS 2019; 2019:5631083. [PMID: 31191752 PMCID: PMC6525907 DOI: 10.1155/2019/5631083] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 03/27/2019] [Indexed: 12/16/2022]
Abstract
Background Age-related macular degeneration (AMD) is a progressive neurodegenerative disease of a central part of the neural retina (macula) and a leading cause of blindness in elderly people. While it is known that the AMD is a multifactorial disease, genetic factors involved in lipid metabolism, inflammation, and neovascularization are currently being widely studied in genome-wide association studies (GWAS). The aim of our study was to evaluate the impact of new single nucleotide polymorphisms (SNPs) in RAD51B, TRIB1, COL8A1, and COL10A1 genes on AMD development. Methods Case-control study involved 254 patients diagnosed with early AMD, 244 patients with exudative AMD, and 942 control subjects. The genotyping of RAD51B (rs8017304 and rs2588809), TRIB1 (rs6987702, rs4351379, and rs4351376), COL8A1 (rs13095226), and COL10A1 (rs1064583) was carried out using TaqMan assays by a real-time polymerase chain reaction (RT-PCR) method. Results Statistically significant difference was found in genotype (TT, TC, and CC) distribution of COL8A1 rs13095226 between exudative AMD and control groups (60.2%, 33.6%, and 6.1% vs. 64.9%, 32.3%, and 2.9%, respectively, p = 0.036). Also, comparing with TT+TC, rs13095226 CC genotype was associated with 3.5-fold increased odds of exudative AMD development (OR = 3.540; 95% CI: 1.415-8.856; p = 0.007). Conclusion Our study revealed a strong association between a variant in COL8A1 (rs13095226) and exudative AMD development.
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Pan HY, Alamri AH, Valapala M. Nutrient deprivation and lysosomal stress induce activation of TFEB in retinal pigment epithelial cells. Cell Mol Biol Lett 2019; 24:33. [PMID: 31160892 PMCID: PMC6537441 DOI: 10.1186/s11658-019-0159-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 05/15/2019] [Indexed: 12/03/2022] Open
Abstract
Background Induction of lysosomal function and autophagy is regarded as an adaptive mechanism in response to cellular stress. The transcription factor EB (TFEB) has been identified as a master regulator of lysosomal function and autophagy. TFEB is a member of the microphthalmia family of bHLH-LZ transcription factors that includes other members such as micropthalmia-associated transcription factor (MITF), TFE3, and TFEC. TFEB controls lysosome biogenesis and autophagy by upregulation of a family of genes belonging to the Coordinated Lysosomal Expression and Regulation (CLEAR) network. Here, we investigated the expression of TFEB in cells subjected to nutrient deprivation and lysosomal stress. We studied transcriptional induction of TFEB-regulated genes in response to nutrient deprivation and lysosomal stress in retinal pigment epithelial (RPE) cells. Furthermore, we also investigated the induction of autophagy and lysosomal genes upon overexpression of constitutively active form of TFEB. Methods Expression of TFEB and MITF protein levels were evaluated in cells subjected to prolonged periods of nutrient deprivation. mRNA levels of the CLEAR network genes was measured by quantitative real time PCR (qRT-PCR) analysis in cells deprived of nutrients, treated with ammonium chloride and upon overexpression of constitutively active TFEB. Immunostaining with LC3 antibody was used to measure autophagy flux. Labeling with lysoTracker dye was used to assess lysosomes. Results Our results show that nutrient deprivation increases protein levels of TFEB and MITF in ARPE-19 cells. Nutrient stress induces the expression of lysosomal (LAMP1, CTSD MCOLN1, SGSH) and autophagy (BECN1) genes. Lysosomal stress also increases the expression of lysosomal (ATP6V0A1 and LAMP1) and autophagy (p62 and BECN1) genes. Our results show that overexpression of constitutively active TFEB also induces the expression of CLEAR network genes. Conclusions Collectively, these observations suggest that nutrient stress induces the protein expression of both MITF and TFEB in ARPE-19 cells. TFEB-regulated transcriptional program plays an important role in adaptive response of cells during both nutrient and lysosomal stress.
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Affiliation(s)
- Hsuan-Yeh Pan
- 1School of Optometry, Indiana University, Bloomington, IN 47405 USA
| | - Abdulla H Alamri
- 2State University of New York College of Optometry, 33 42nd St., New York, NY 10036 USA
| | - Mallika Valapala
- 1School of Optometry, Indiana University, Bloomington, IN 47405 USA
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