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Abstract
Light has a crucial role in the visual process. For nonvisible radiation in the short-wave spectrum, there are natural mechanisms that protect the human retina from damaging ultraviolet (UV) radiation. Here, the dose (= energy) makes the poison. Damage caused by UV light mainly affects the outer retina, particularly the photoreceptors and the retinal pigment epithelium. While retinal damage due to increased UV radiation exposure can potentially still occur up to the age of 20, in adulthood, exposure of the retina to UV radiation can no longer be assumed, due to decreasing transmission properties of the natural lens. The natural lens, modern intraocular lenses, and wearing of sunglasses with appropriate filter function, particularly in childhood and adolescence, provide a relevant reduction in UV radiation exposure of the retina.
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Affiliation(s)
| | - Thomas Ach
- Augenklinik, Universitätsklinikum Bonn, Venusberg-Campus 1, 53127, Bonn, Deutschland.
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2
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Sun S, Cai B, Li Y, Su W, Zhao X, Gong B, Li Z, Zhang X, Wu Y, Chen C, Tsang SH, Yang J, Li X. HMGB1 and Caveolin-1 related to RPE cell senescence in age-related macular degeneration. Aging (Albany NY) 2020; 11:4323-4337. [PMID: 31284269 PMCID: PMC6660032 DOI: 10.18632/aging.102039] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 06/20/2019] [Indexed: 01/09/2023]
Abstract
Accumulation of lipofuscin in the retinal pigment epithelium (RPE) is considered a major cause of RPE dysfunction and senescence in age-related macular degeneration (AMD), and N-retinylidene-N-retinylethanolamine (A2E) is the main fluorophore identified in lipofuscin from aged human eyes. Here, human-induced pluripotent stem cell (iPSC)-RPE was generated from healthy individuals to reveal proteomic changes associated with A2E-related RPE cell senescence. A novel RPE cell senescence-related protein, high-mobility group box 1 (HMGB1), was identified based on proteomic mass spectrometry measurements on iPSC-RPE with A2E treatment. Furthermore, HMGB1 upregulated Caveolin-1, which also was related RPE cell senescence. To investigate whether changes in HMGB1 and Caveolin-1 expression under A2E exposure contribute to RPE cell senescence, human ARPE-19 cells were stimulated with A2E; expression of HMGB1, Caveolin-1, tight junction proteins and senescent phenotypes were verified. HMGB1 inhibition alleviated A2E induced cell senescence. Migration of RPE cells was evaluated. Notably, A2E less than or equal to 10μM induced both HMGB1 and Caveolin-1 protein upregulation and HMGB1 translocation, while Caveolin-1 expression was downregulated when there was more than 10μM A2E. Our data indicate that A2E-induced upregulation of HMGB1、Caveolin-1 and HMGB1 release may relate to RPE cell senescence and play a role in the pathogenesis of AMD.
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Affiliation(s)
- Shuo Sun
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Bincui Cai
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Yao Li
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA.,Departments of Ophthalmology, Columbia University, New York, NY 10027, USA
| | - Wenqi Su
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Xuzheng Zhao
- Tangshan Eye Hospital, Tangshan, People's Republic of China
| | - Boteng Gong
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Zhiqing Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Xiaomin Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Yalin Wu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen City, People's Republic of China
| | - Chao Chen
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen City, People's Republic of China
| | - Stephen H Tsang
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA.,Departments of Ophthalmology, Columbia University, New York, NY 10027, USA
| | - Jin Yang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
| | - Xiaorong Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, People's Republic of China
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3
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Boughton BA, Thomas ORB, Demarais NJ, Trede D, Swearer SE, Grey AC. Detection of small molecule concentration gradients in ocular tissues and humours. JOURNAL OF MASS SPECTROMETRY : JMS 2020; 55:e4460. [PMID: 31654531 DOI: 10.1002/jms.4460] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/02/2019] [Accepted: 10/17/2019] [Indexed: 06/10/2023]
Abstract
The eye is an elegant organ consisting of a number of tissues and fluids with specialised functions that together allow it to effectively transmit and transduce light input to the brain for visual perception. One key determinant of this integrated function is the spatial relationship of ocular tissues. Biomolecular distributions within the main ocular tissues cornea, lens, and retina have been studied extensively in isolation, yet the potential for metabolic communication between ocular tissues via the ocular humours has been difficult to visualise. To address this limitation, the current study presents a method to map spatial distributions of metabolites and small molecules in whole eyes, including ocular humours. Using a tape-transfer system and freeze-drying, the spatial distribution of ocular small molecules was investigated in mouse, rat, fish (black bream), and rabbit eyes using negative ion mode MALDI imaging mass spectrometry. Full-scan imaging was used for discovery experiments, while MS/MS imaging for identification and localisation was also demonstrated. In all eyes, metabolites such as glutathione and phospholipids were localised in the main ocular tissues. In addition, in rodent eyes, major metabolites were distributed relatively uniformly in ocular humours. In contrast, both uniform and spatially defined ocular metabolite distributions were observed in the black bream eye. Tissue and ocular humour distributions were reproducible, as demonstrated by the three-dimensional analysis of a mouse eye, and able to be captured with high spatial resolution analysis. The presented method could be used to further investigate the role of inter-tissue metabolism in ocular health, and to support the development of therapeutics to treat major ocular diseases.
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Affiliation(s)
- Berin A Boughton
- Metabolomics Australia, University of Melbourne, Melbourne, Australia
| | - Oliver R B Thomas
- School of BioSciences, University of Melbourne, Melbourne, Australia
| | - Nicholas J Demarais
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | | | - Stephen E Swearer
- School of BioSciences, University of Melbourne, Melbourne, Australia
| | - Angus C Grey
- School of Medical Sciences, University of Auckland, Auckland, New Zealand
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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: 3.5] [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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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: 10] [Impact Index Per Article: 2.0] [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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6
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Groseclose MR, Castellino S. An Investigation into Retigabine (Ezogabine) Associated Dyspigmentation in Rat Eyes by MALDI Imaging Mass Spectrometry. Chem Res Toxicol 2019; 32:294-303. [PMID: 30638013 DOI: 10.1021/acs.chemrestox.8b00313] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Retigabine (RTG) is an antiepileptic drug approved as an adjunctive treatment for refractory partial-onset seizures in adults. In April 2013, the Food and Drug Administration issued a warning that RTG could cause changes in retinal pigmentation and discoloration of skin, resulting in a blue appearance. As part of a larger preclinical effort to gain a mechanistic understanding as to the origins of retinal pigment changes associated with RTG, we conducted a long-term repeat dosing study in rats. Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) was used to determine the distribution of RTG and its metabolites in the rat eye following 13 and 39 weeks of dosing. IMS revealed the presence of RTG, a previously characterized N-acetyl metabolite of RTG (NAMR), and several species structurally related through the dimerization of RTG and NAMR. These species were highly localized to the melanin-containing layers of the uveal tract of the rat eye including the choroid, ciliary body, and iris, suggesting that the formation of these dimers occurs from melanin bound RTG and NAMR. Furthermore, several of the RTG-related dimers have UV absorbance which give them a purple color in solution. We propose that the melanin binding of RTG and NAMR effectively concentrates the two compounds to enable mixed condensation reactions to occur when the binding provides the proper geometry in the redox environment of the uveal tissues. High lateral resolution images illustrate that the blood-retinal barrier effectively restricts retinal access to RTG-related compounds. The spatial information provided by MALDI IMS was critical in contextualizing the homogenate concentrations of key RTG-related compounds and helped provide a basis for the mechanism of dimer formation.
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Affiliation(s)
- M Reid Groseclose
- Department of Bioimaging , GlaxoSmithKline , 1250 S. Collegeville Road , Collegeville , Pennsylvania 19426 , United States
| | - Stephen Castellino
- Department of Bioimaging , GlaxoSmithKline , 1250 S. Collegeville Road , Collegeville , Pennsylvania 19426 , United States
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Leclaire MD, Nettels-Hackert G, König J, Höhn A, Grune T, Uhlig CE, Hansen U, Eter N, Heiduschka P. Lipofuscin-dependent stimulation of microglial cells. Graefes Arch Clin Exp Ophthalmol 2019; 257:931-952. [PMID: 30693383 DOI: 10.1007/s00417-019-04253-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 01/10/2019] [Accepted: 01/17/2019] [Indexed: 01/10/2023] Open
Abstract
PURPOSE To examine the reaction of microglial cells (MG) when incubated with lipofuscin (LP) in vitro with emphasis on the immunological reaction of the MG toward LP and the suppression of this reaction by immunomodulatory agents. MG are involved in the pathogenesis of degenerative eye disorders such as age-related macular degeneration (AMD). LP is a heterogeneous waste material that accumulates in the retinal pigment epithelium (RPE) cells with advancing age. LP is known to have toxic effects on RPE cells and therefore an elevated LP-derived fundus autofluorescence is a risk factor for AMD development. MG in the subretinal space have been reported in eyes affected by AMD. Moreover, in senescent mice, subretinal MG were found, which display an autofluorescence that may be derived from LP uptake. METHODS In this study, we incubated MG (BV-2 cell line and primary cells from murine brain) in vitro with LP isolated from the human RPE. We observed phagocytosis, studied cell morphologies, and analyzed the cell culture supernatants. We also investigated the effect of the immunomodulatory agents hydrocortisone (HC), minocycline, and the tripeptide TKP. RESULTS The MG phagocytosed the LP quickly and completely. We detected highly elevated levels of pro-inflammatory cytokines (especially of IL-6, IL-23p19, TNF-α, KC, RANTES, and IL-1α) in the cell culture supernatants. Furthermore, levels of vascular endothelial growth factor (VEGF) were raised in BV-2 cells. Anti-inflammatory agents added to the cell cultures inhibited the inflammatory reaction, in particular hydrocortisone (HC). Minocycline and TKP had less impact on the cytokine release. CONCLUSION The interaction of MG and LP could play a role in the development of retinal degeneration by triggering an inflammatory reaction and angiogenesis.
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Affiliation(s)
- Martin Dominik Leclaire
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany
| | - Gerburg Nettels-Hackert
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany
| | - Jeannette König
- German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany
| | - Annika Höhn
- German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany
| | - Tilman Grune
- German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany
| | - Constantin E Uhlig
- Cornea Bank Münster, Department of Ophthalmology, University Medical Center, Münster, Germany
| | - Uwe Hansen
- Institute of Experimental Musculoskeletal Medicine, Medical Faculty, University of Münster, Münster, Germany
| | - Nicole Eter
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany
| | - Peter Heiduschka
- Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany.
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von Eisenhart-Rothe P, Grubman A, Greferath U, Fothergill LJ, Jobling AI, Phipps JA, White AR, Fletcher EL, Vessey KA. Failure of Autophagy–Lysosomal Pathways in Rod Photoreceptors Causes the Early Retinal Degeneration Phenotype Observed inCln6nclfMice. ACTA ACUST UNITED AC 2018; 59:5082-5097. [DOI: 10.1167/iovs.18-24757] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
| | - Alexandra Grubman
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Linda J. Fothergill
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Andrew I. Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Joanna A. Phipps
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Anthony R. White
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Erica L. Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Kirstan A. Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
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9
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Stark DT, Anderson DMG, Kwong JMK, Patterson NH, Schey KL, Caprioli RM, Caprioli J. Optic Nerve Regeneration After Crush Remodels the Injury Site: Molecular Insights From Imaging Mass Spectrometry. Invest Ophthalmol Vis Sci 2018; 59:212-222. [PMID: 29340649 PMCID: PMC5770179 DOI: 10.1167/iovs.17-22509] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Mammalian central nervous system axons fail to regenerate after injury. Contributing factors include limited intrinsic growth capacity and an inhibitory glial environment. Inflammation-induced optic nerve regeneration (IIR) is thought to boost retinal ganglion cell (RGC) intrinsic growth capacity through progrowth gene expression, but effects on the inhibitory glial environment of the optic nerve are unexplored. To investigate progrowth molecular changes associated with reactive gliosis during IIR, we developed an imaging mass spectrometry (IMS)-based approach that identifies discriminant molecular signals in and around optic nerve crush (ONC) sites. Methods ONC was performed in rats, and IIR was established by intravitreal injection of a yeast cell wall preparation. Optic nerves were collected at various postcrush intervals, and longitudinal sections were analyzed with matrix-assisted laser desorption/ionization (MALDI) IMS and data mining. Immunohistochemistry and confocal microscopy were used to compare discriminant molecular features with cellular features of reactive gliosis. Results IIR increased the area of the crush site that was occupied by a dense cellular infiltrate and mass spectral features consistent with lysosome-specific lipids. IIR also increased immunohistochemical labeling for microglia and macrophages. IIR enhanced clearance of lipid sulfatide myelin-associated inhibitors of axon growth and accumulation of simple GM3 gangliosides in a spatial distribution consistent with degradation of plasma membrane from degenerated axons. Conclusions IIR promotes a robust phagocytic response that improves clearance of myelin and axon debris. This growth-permissive molecular remodeling of the crush injury site extends our current understanding of IIR to include mechanisms extrinsic to the RGC.
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Affiliation(s)
- David T Stark
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - David M G Anderson
- Vanderbilt Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Jacky M K Kwong
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - Nathan Heath Patterson
- Vanderbilt Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Kevin L Schey
- Vanderbilt Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Richard M Caprioli
- Vanderbilt Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Joseph Caprioli
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States
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10
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Anderson DMG, Ablonczy Z, Koutalos Y, Hanneken AM, Spraggins JM, Calcutt MW, Crouch RK, Caprioli RM, Schey KL. Bis(monoacylglycero)phosphate lipids in the retinal pigment epithelium implicate lysosomal/endosomal dysfunction in a model of Stargardt disease and human retinas. Sci Rep 2017; 7:17352. [PMID: 29229934 PMCID: PMC5725462 DOI: 10.1038/s41598-017-17402-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 11/22/2017] [Indexed: 01/10/2023] Open
Abstract
Stargardt disease is a juvenile onset retinal degeneration, associated with elevated levels of lipofuscin and its bis-retinoid components, such as N-retinylidene-N-retinylethanolamine (A2E). However, the pathogenesis of Stargardt is still poorly understood and targeted treatments are not available. Utilizing high spatial and high mass resolution matrix assisted laser desorption ionization (MALDI) imaging mass spectrometry (IMS), we determined alterations of lipid profiles specifically localized to the retinal pigment epithelium (RPE) in Abca4 -/- Stargardt model mice compared to their relevant background strain. Extensive analysis by LC-MS/MS in both positive and negative ion mode was required to accurately confirm the identity of one highly expressed lipid class, bis(monoacylgylercoro)phosphate (BMP) lipids, and to distinguish them from isobaric species. The same BMP lipids were also detected in the RPE of healthy human retina. BMP lipids have been previously associated with the endosomal/lysosomal storage diseases Niemann-Pick and neuronal ceroid lipofuscinosis and have been reported to regulate cholesterol levels in endosomes. These results suggest that perturbations in lipid metabolism associated with late endosomal/lysosomal dysfunction may play a role in the pathogenesis of Stargardt disease and is evidenced in human retinas.
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Affiliation(s)
- David M G Anderson
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Zsolt Ablonczy
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
- Preclinical Department, Ora Inc, Andover, MA, USA
| | - Yiannis Koutalos
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
| | - Anne M Hanneken
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Jeffrey M Spraggins
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
- Department of Chemistry, Nashville, TN, USA
| | - M Wade Calcutt
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Rosalie K Crouch
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
| | - Richard M Caprioli
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
- Department of Chemistry, Nashville, TN, USA
- Department of Pharmacology and Medicine, Vanderbilt University, Nashville, TN, USA
| | - Kevin L Schey
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA.
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11
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Ferreira MS, de Oliveira DN, Mesquita CC, Barbosa APDL, Anhê GF, Catharino RR. MALDI-MSI: a fast and reliable method for direct melatonin quantification in biological fluids. J Anal Sci Technol 2016. [DOI: 10.1186/s40543-016-0106-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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12
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Fronk AH, Vargis E. Methods for culturing retinal pigment epithelial cells: a review of current protocols and future recommendations. J Tissue Eng 2016; 7:2041731416650838. [PMID: 27493715 PMCID: PMC4959307 DOI: 10.1177/2041731416650838] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/23/2016] [Indexed: 12/17/2022] Open
Abstract
The retinal pigment epithelium is an important part of the vertebrate eye, particularly in studying the causes and possible treatment of age-related macular degeneration. The retinal pigment epithelium is difficult to access in vivo due to its location at the back of the eye, making experimentation with age-related macular degeneration treatments problematic. An alternative to in vivo experimentation is cultivating the retinal pigment epithelium in vitro, a practice that has been going on since the 1970s, providing a wide range of retinal pigment epithelial culture protocols, each producing cells and tissue of varying degrees of similarity to natural retinal pigment epithelium. The purpose of this review is to provide researchers with a ready list of retinal pigment epithelial protocols, their effects on cultured tissue, and their specific possible applications. Protocols using human and animal retinal pigment epithelium cells, derived from tissue or cell lines, are discussed, and recommendations for future researchers included.
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Affiliation(s)
- Aaron H Fronk
- Department of Biological Engineering, Utah State University, Logan, UT, USA
| | - Elizabeth Vargis
- Department of Biological Engineering, Utah State University, Logan, UT, USA
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13
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Pallitto P, Ablonczy Z, Jones EE, Drake RR, Koutalos Y, Crouch RK, Donello J, Herrmann J. A2E and lipofuscin distributions in macaque retinal pigment epithelium are similar to human. Photochem Photobiol Sci 2016. [PMID: 26223373 DOI: 10.1039/c5pp00170f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The accumulation of lipofuscin, an autofluorescent aging marker, in the retinal pigment epithelium (RPE) has been implicated in the development of age-related macular degeneration (AMD). Lipofuscin contains several visual cycle byproducts, most notably the bisretinoid N-retinylidene-N-retinylethanolamine (A2E). Previous studies with human donor eyes have shown a significant mismatch between lipofuscin autofluorescence (AF) and A2E distributions. The goal of the current project was to examine this relationship in a primate model with a retinal anatomy similar to that of humans. Ophthalmologically naive young (<10 years., N = 3) and old (>10 years., N = 4) Macaca fascicularis (macaque) eyes, were enucleated, dissected to yield RPE/choroid tissue, and flat-mounted on indium-tin-oxide-coated conductive slides. To compare the spatial distributions of lipofuscin and A2E, fluorescence and mass spectrometric imaging were carried out sequentially on the same samples. The distribution of lipofuscin fluorescence in the primate RPE reflected previously obtained human results, having the highest intensities in a perifoveal ring. Contrarily, A2E levels were consistently highest in the periphery, confirming a lack of correlation between the distributions of lipofuscin and A2E previously described in human donor eyes. We conclude that the mismatch between lipofuscin AF and A2E distributions is related to anatomical features specific to primates, such as the macula, and that this primate model has the potential to fill an important gap in current AMD research.
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Affiliation(s)
- Patrick Pallitto
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, USA.
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14
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Adler L, Boyer NP, Anderson DM, Spraggins JM, Schey KL, Hanneken A, Ablonczy Z, Crouch RK, Koutalos Y. Determination of N-retinylidene-N-retinylethanolamine (A2E) levels in central and peripheral areas of human retinal pigment epithelium. Photochem Photobiol Sci 2016; 14:1983-90. [PMID: 26323192 DOI: 10.1039/c5pp00156k] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The bis-retinoid N-retinylidene-N-retinylethanolamine (A2E) is one of the major components of lipofuscin, a fluorescent material that accumulates with age in the lysosomes of the retinal pigment epithelium (RPE) of the human eye. Lipofuscin, as well as A2E, exhibit a range of cytotoxic properties, which are thought to contribute to the pathogenesis of degenerative diseases of the retina such as Age-related Macular Degeneration. Consistent with such a pathogenic role, high levels of lipofuscin fluorescence are found in the central area of the human RPE, and decline toward the periphery. Recent reports have however suggested a surprising incongruence between the distributions of lipofuscin and A2E in the human RPE, with A2E levels being lowest in the central area and increasing toward the periphery. To appraise such a possibility, we have quantified the levels of A2E in the central and peripheral RPE areas of 10 eyes from 6 human donors (ages 75-91 years) with HPLC and UV/VIS spectroscopy. The levels of A2E in the central area were on average 3-6 times lower than in peripheral areas of the same eye. Furthermore, continuous accumulation of selected ions (CASI) imaging mass spectrometry showed the presence of A2E in the central RPE, and at lower intensities than in the periphery. We have therefore corroborated that in human RPE the levels of A2E are lower in the central area compared to the periphery. We conclude that the levels of A2E cannot by themselves provide an explanation for the higher lipofuscin fluorescence found in the central area of the human RPE.
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Affiliation(s)
- Leopold Adler
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA.
| | - Nicholas P Boyer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA.
| | - David M Anderson
- Mass Spectrometry Research Center, Vanderbilt School of Medicine, Nashville, TN, USA
| | - Jeffrey M Spraggins
- Mass Spectrometry Research Center, Vanderbilt School of Medicine, Nashville, TN, USA
| | - Kevin L Schey
- Mass Spectrometry Research Center, Vanderbilt School of Medicine, Nashville, TN, USA
| | - Anne Hanneken
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Zsolt Ablonczy
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA.
| | - Rosalie K Crouch
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA.
| | - Yiannis Koutalos
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA.
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15
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Bowrey HE, Anderson DM, Pallitto P, Gutierrez DB, Fan J, Crouch RK, Schey KL, Ablonczy Z. Imaging mass spectrometry of the visual system: Advancing the molecular understanding of retina degenerations. Proteomics Clin Appl 2016; 10:391-402. [PMID: 26586164 DOI: 10.1002/prca.201500103] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 08/15/2015] [Accepted: 11/11/2015] [Indexed: 11/08/2022]
Abstract
Visual sensation is fundamental for quality of life, and loss of vision to retinal degeneration is a debilitating condition. The eye is the only part of the central nervous system that can be noninvasively observed with optical imaging. In the clinics, various spectroscopic methods provide high spatial resolution images of the fundus and the developing degenerative lesions. However, the currently utilized tools are not specific enough to establish the molecular underpinnings of retinal diseases. In contrast, mass spectrometric imaging (MSI) is a powerful tool to identify molecularly specific disease indicators and classification markers. This technique is particularly well suited to the eye, where molecular information can be correlated with clinical data collected via noninvasive diagnostic imaging modalities. Recent studies during the last few recent years have uncovered a plethora of new spatially defined molecular information on several vision-threatening diseases, including age-related macular degeneration, Stargardt disease, glaucoma, cataract, as well as lipid disorders. Even though MS inside the eye cannot be performed noninvasively, by linking diagnostic and molecular information, these studies are the first step toward the development of smart ophthalmic diagnostic and surgical tools. Here, we provide an overview of current approaches applying MSI technology to ocular pathology.
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Affiliation(s)
- Hannah E Bowrey
- Brain Health Institute, Rutgers University, New Brunswick, NJ, USA
| | - David M Anderson
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Patrick Pallitto
- Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, USA
| | - Danielle B Gutierrez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jie Fan
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA
| | - Rosalie K Crouch
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA
| | - Kevin L Schey
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Zsolt Ablonczy
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA
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16
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The Photobiology of Lutein and Zeaxanthin in the Eye. J Ophthalmol 2015; 2015:687173. [PMID: 26798505 PMCID: PMC4698938 DOI: 10.1155/2015/687173] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/15/2015] [Indexed: 12/31/2022] Open
Abstract
Lutein and zeaxanthin are antioxidants found in the human retina and macula. Recent clinical trials have determined that age- and diet-related loss of lutein and zeaxanthin enhances phototoxic damage to the human eye and that supplementation of these carotenoids has a protective effect against photoinduced damage to the lens and the retina. Two of the major mechanisms of protection offered by lutein and zeaxanthin against age-related blue light damage are the quenching of singlet oxygen and other reactive oxygen species and the absorption of blue light. Determining the specific reactive intermediate(s) produced by a particular phototoxic ocular chromophore not only defines the mechanism of toxicity but can also later be used as a tool to prevent damage.
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17
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Sparrow JR, Duncker T. Fundus Autofluorescence and RPE Lipofuscin in Age-Related Macular Degeneration. J Clin Med 2015; 3:1302-21. [PMID: 25774313 PMCID: PMC4358814 DOI: 10.3390/jcm3041302] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Genes that increase susceptibility to age-related macular degeneration (AMD) have been identified; however, since many individuals carrying these risk alleles do not develop disease, other contributors are involved. One additional factor, long implicated in the pathogenesis of AMD, is the lipofuscin of retinal pigment epithelium (RPE). The fluorophores that constitute RPE lipofuscin also serve as a source of autofluorescence (AF) that can be imaged by confocal laser ophthalmoscopy. The AF originating from lipofuscin is excited by the delivery of short wavelength (SW) light. A second autofluorescence is emitted from the melanin of RPE (and choroid) upon near-infrared (NIR-AF) excitation. SW-AF imaging is currently used in the clinical management of retinal disorders and the advantages of NIR-AF are increasingly recognized. Here we visit the damaging properties of RPE lipofuscin that could be significant when expressed on a background of genetic susceptibility. To advance interpretations of disease-related patterns of fundus AF in AMD, we also consider the photochemical and spectrophotometric features of the lipofuscin compounds responsible for generating the fluorescence emission.
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Affiliation(s)
- Janet R. Sparrow
- Department of Ophthalmology, Columbia University Medical Center, 635 W. 165th Street, New York, NY 10032, USA; E-Mail:
- Department of Pathology and Cell Biology, Columbia University Medical Center, 630 168th Street, New York, NY 10032, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-212-305-0044
| | - Tobias Duncker
- Department of Ophthalmology, Columbia University Medical Center, 635 W. 165th Street, New York, NY 10032, USA; E-Mail:
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18
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Crouch RK, Koutalos Y, Kono M, Schey K, Ablonczy Z. A2E and Lipofuscin. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:449-63. [PMID: 26310170 DOI: 10.1016/bs.pmbts.2015.06.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Lipofuscin is highly fluorescent material, formed in several tissues but best studied in the eye. The accumulation of lipofuscin in the retinal pigment epithelium (RPE) is a hallmark of aging in the eye and has been implicated in various retinal degenerations, including age-related macular degeneration. The bis-retinoid N-retinyl-N-retinylidene ethanolamine (A2E), formed from retinal, has been identified as a byproduct of the visual cycle, and numerous in vitro studies have found toxicity associated with this compound. The compound is known to accumulate in the RPE with age and was the first identified compound extracted from lipofuscin. Our studies have correlated the distribution of lipofuscin and A2E across the human and mouse RPE. Lipofuscin fluorescence was imaged in the RPE from human donors of various ages and from assorted mouse models. The spatial distribution of A2E was determined using matrix-assisted laser desorption-ionization imaging mass spectrometry on both flat-mounted and transversally sectioned RPE tissue. Our data support the clinical observations in humans of strong RPE fluorescence, increasing with age, in the central area of the RPE. However, there was no correlation between the distribution of A2E and lipofuscin, as the levels of A2E were highest in the far periphery and decreased toward the central region. Interestingly, in all the mouse models, A2E distribution and lipofuscin fluorescence correlate well. These data demonstrate that the accumulation of A2E is not responsible for the increase in lipofuscin fluorescence observed in the central RPE with aging in humans.
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Affiliation(s)
- Rosalie K Crouch
- Department of Ophthalmology, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.
| | - Yiannis Koutalos
- Department of Ophthalmology, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Masahiro Kono
- Department of Ophthalmology, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Kevin Schey
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Zsolt Ablonczy
- Department of Ophthalmology, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA
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19
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Marquioni-Ramella MD, Suburo AM. Photo-damage, photo-protection and age-related macular degeneration. Photochem Photobiol Sci 2015. [DOI: 10.1039/c5pp00188a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The course of Age-related Macular Degeneration (AMD) is described as the effect of light (400–580 nm) on various molecular targets in photoreceptors and the retinal pigment epithelium (RPE). Photo-damage is followed by inflammation, increasing oxidative stress and, probably, unveiling new photosensitive molecules.
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Affiliation(s)
| | - Angela M. Suburo
- Medicina Celular y Molecular
- Facultad de Ciencias Biomédicas
- Universidad Austral
- Pilar B1629AHJ
- Argentina
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20
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Ly A, Schöne C, Becker M, Rattke J, Meding S, Aichler M, Suckau D, Walch A, Hauck SM, Ueffing M. High-resolution MALDI mass spectrometric imaging of lipids in the mammalian retina. Histochem Cell Biol 2014; 143:453-62. [DOI: 10.1007/s00418-014-1303-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2014] [Indexed: 12/12/2022]
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21
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Sun N, Ly A, Meding S, Witting M, Hauck SM, Ueffing M, Schmitt-Kopplin P, Aichler M, Walch A. High-resolution metabolite imaging of light and dark treated retina using MALDI-FTICR mass spectrometry. Proteomics 2014; 14:913-23. [PMID: 24459044 DOI: 10.1002/pmic.201300407] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/06/2013] [Accepted: 12/20/2013] [Indexed: 11/06/2022]
Abstract
MS imaging (MSI) is a valuable tool for diagnostics and systems biology studies, being a highly sensitive, label-free technique capable of providing comprehensive spatial distribution of different classes of biomolecules. The application of MSI to the study of endogenous compounds has received considerable attention because metabolites are the result of the interactions of a biosystem with its environment. MSI can therefore enhance understanding of disease mechanisms and elucidate mechanisms for biological variation. We present the in situ comparative metabolomics imaging data for analyses of light- and dark-treated retina using MALDI-FTICR. A wide variety of tissue metabolites were imaged at a high spatial resolution. These include nucleotides, central carbon metabolism pathway intermediates, 2-oxocarboxylic acid metabolism, oxidative phosphorylation, glycerophospholipid metabolism, and cysteine and methionine metabolites. The high lateral resolution enabled the differentiation of retinal layers, allowing determination of the spatial distributions of different endogenous compounds. A number of metabolites demonstrated differences between light and dark conditions. These findings add to the understanding of metabolic activity in the retina.
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Affiliation(s)
- Na Sun
- Research Unit Analytical Pathology, Institute of Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Neuherberg, Germany
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22
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Anderson DMG, Ablonczy Z, Koutalos Y, Spraggins J, Crouch RK, Caprioli RM, Schey KL. High resolution MALDI imaging mass spectrometry of retinal tissue lipids. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:1394-403. [PMID: 24819461 PMCID: PMC4180438 DOI: 10.1007/s13361-014-0883-2] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/05/2014] [Accepted: 03/14/2014] [Indexed: 05/11/2023]
Abstract
Matrix assisted laser desorption ionization imaging mass spectrometry (MALDI IMS) has the ability to provide an enormous amount of information on the abundances and spatial distributions of molecules within biological tissues. The rapid progress in the development of this technology significantly improves our ability to analyze smaller and smaller areas and features within tissues. The mammalian eye has evolved over millions of years to become an essential asset for survival, providing important sensory input of an organism's surroundings. The highly complex sensory retina of the eye is comprised of numerous cell types organized into specific layers with varying dimensions, the thinnest of which is the 10 μm retinal pigment epithelium (RPE). This single cell layer and the photoreceptor layer contain the complex biochemical machinery required to convert photons of light into electrical signals that are transported to the brain by axons of retinal ganglion cells. Diseases of the retina, including age-related macular degeneration (AMD), retinitis pigmentosa, and diabetic retinopathy, occur when the functions of these cells are interrupted by molecular processes that are not fully understood. In this report, we demonstrate the use of high spatial resolution MALDI IMS and FT-ICR tandem mass spectrometry in the Abca4(-/-) knockout mouse model of Stargardt disease, a juvenile onset form of macular degeneration. The spatial distributions and identity of lipid and retinoid metabolites are shown to be unique to specific retinal cell layers.
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Affiliation(s)
- David M. G. Anderson
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN
| | - Zsolt Ablonczy
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, SC
| | - Yiannis Koutalos
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, SC
| | - Jeffrey Spraggins
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN
| | - Rosalie K. Crouch
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, SC
| | - Richard M. Caprioli
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN
- Department of Chemistry, Pharmacology and Medicine, Vanderbilt University, Nashville, TN
| | - Kevin L. Schey
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN
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23
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Ach T, Huisingh C, McGwin G, Messinger JD, Zhang T, Bentley MJ, Gutierrez DB, Ablonczy Z, Smith RT, Sloan KR, Curcio CA. Quantitative autofluorescence and cell density maps of the human retinal pigment epithelium. Invest Ophthalmol Vis Sci 2014; 55:4832-41. [PMID: 25034602 DOI: 10.1167/iovs.14-14802] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
PURPOSE Lipofuscin (LF) accumulation within RPE cells is considered pathogenic in AMD. To test whether LF contributes to RPE cell loss in aging and to provide a cellular basis for fundus autofluorescence (AF) we created maps of human RPE cell number and histologic AF. METHODS Retinal pigment epithelium-Bruch's membrane flat mounts were prepared from 20 donor eyes (10 ≤ 51 and 10 > 80 years; postmortem: ≤4.2 hours; no retinal pathologies), preserving foveal position. Phalloidin-binding RPE cytoskeleton and LF-AF (488-nm excitation) were imaged at up to 90 predefined positions. Maps were assembled from 83,330 cells in 1470 locations. From Voronoi regions representing each cell, the number of neighbors, cell area, and total AF intensity normalized to an AF standard was determined. RESULTS Highly variable between individuals, RPE-AF increases significantly with age. A perifoveal ring of high AF mirrors rod photoreceptor topography and fundus-AF. Retinal pigment epithelium cell density peaks at the fovea, independent of age, yet no net RPE cell loss is detectable. The RPE monolayer undergoes considerable lifelong re-modeling. The relationship of cell size and AF, a surrogate for LF concentration, is orderly and linear in both groups. Autofluorescence topography differs distinctly from the topography of age-related rod loss. CONCLUSIONS Digital maps of quantitative AF, cell density, and packing geometry provide metrics for cellular-resolution clinical imaging and model systems. The uncoupling of RPE LF content, cell number, and photoreceptor topography in aging challenges LF's role in AMD.
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Affiliation(s)
- Thomas Ach
- University of Alabama at Birmingham, Department of Ophthalmology, Birmingham, Alabama, United States
| | - Carrie Huisingh
- University of Alabama at Birmingham, Department of Ophthalmology, Birmingham, Alabama, United States
| | - Gerald McGwin
- University of Alabama at Birmingham, Department of Ophthalmology, Birmingham, Alabama, United States University of Alabama at Birmingham, Department of Epidemiology, Birmingham, Alabama, United States
| | - Jeffrey D Messinger
- University of Alabama at Birmingham, Department of Ophthalmology, Birmingham, Alabama, United States
| | - Tianjiao Zhang
- University of Alabama at Birmingham, Department of Ophthalmology, Birmingham, Alabama, United States
| | - Mark J Bentley
- University of Alabama at Birmingham, Department of Computer and Information Sciences, Birmingham, Alabama, United States
| | - Danielle B Gutierrez
- Center for Coastal Studies, Texas A&M University-Corpus Christi, Corpus Christi, Texas, United States
| | - Zsolt Ablonczy
- Medical University of South Carolina, Department of Ophthalmology, Charleston, South Carolina, United States
| | - R Theodore Smith
- New York University School of Medicine, Department of Ophthalmology, New York, New York, United States
| | - Kenneth R Sloan
- University of Alabama at Birmingham, Department of Computer and Information Sciences, Birmingham, Alabama, United States
| | - Christine A Curcio
- University of Alabama at Birmingham, Department of Ophthalmology, Birmingham, Alabama, United States
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24
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Gordon WC, Bazan NG. Mediator lipidomics in ophthalmology: targets for modulation in inflammation, neuroprotection and nerve regeneration. Curr Eye Res 2014; 38:995-1005. [PMID: 23981028 DOI: 10.3109/02713683.2013.827211] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Studies in the central nervous system (CNS) and retina have revealed the significance of docosahexaenoic acid (DHA), an essential omega-3, 22 carbon 6 double bond (22:6), fatty acid. DHA is necessary for various functions in the CNS, including neuronal membrane bio- and synaptogenesis in memory and vision, and it is the precursor for docosanoids and neuroprotectin D1 (NPD1; 10R,17S-dihydroxy-docosa-4Z,7Z,11E,13E,15Z,19Z hexaenoic acid), a DHA bio-derivative with neuroprotective properties. This review covers three targets in ophthalmology for mediator lipidomics, a subgroup within the field of metabolomics: inflammation, neuroprotection and nerve regeneration. It also discusses the role DHA, NPD1 and other lipid mediators play in these three areas.
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Affiliation(s)
- William C Gordon
- Neuroscience Center of Excellence and Department of Ophthalmology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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25
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Wu L, Ueda K, Nagasaki T, Sparrow JR. Light damage in Abca4 and Rpe65rd12 mice. Invest Ophthalmol Vis Sci 2014; 55:1910-8. [PMID: 24576873 DOI: 10.1167/iovs.14-13867] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
PURPOSE Bisretinoids form in photoreceptor cells and accumulate in retinal pigment epithelium (RPE) as lipofuscin. To examine the role of these fluorophores as mediators of retinal light damage, we studied the propensity for light damage in mutant mice having elevated lipofuscin due to deficiency in the ATP-binding cassette (ABC) transporter Abca4 (Abca4(-/-) mice) and in mice devoid of lipofuscin owing to absence of Rpe65 (Rpe65(rd12)). METHODS Abca4(-/-), Rpe65(rd12), and wild-type mice were exposed to 430-nm light to produce a localized lesion in the superior hemisphere of retina. Bisretinoids of RPE lipofuscin were measured by HPLC. In histologic sections, outer nuclear layer (ONL) thickness was measured as an indicator of photoreceptor cell degeneration, and RPE nuclei were counted. RESULTS As shown previously, A2E levels were increased in Abca4(-/-) mice. These mice also sustained light damage-associated ONL thinning that was more pronounced than in age-matched wild-type mice; the ONL thinning was also greater in 5-month versus 2-month-old mice. Numbers of RPE nuclei were reduced in light-stressed mice, with the reduction being greater in the Abca4(-/-) than wild-type mice. In Rpe65(rd12) mice bisretinoid compounds of RPE lipofuscin were not detected chromatographically and light damage-associated ONL thinning was not observed. CONCLUSIONS Abca4(-/-) mice that accumulate RPE lipofuscin at increased levels were more susceptible to retinal light damage than wild-type mice. This finding, together with results showing that Rpe65(rd12) mice did not accumulate lipofuscin and did not sustain retinal light damage, indicates that the bisretinoids of retinal lipofuscin are contributors to retinal light damage.
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Affiliation(s)
- Li Wu
- Department of Ophthalmology, Columbia University, New York, New York
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26
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Ablonczy Z, Smith N, Anderson DM, Grey AC, Spraggins J, Koutalos Y, Schey KL, Crouch RK. The utilization of fluorescence to identify the components of lipofuscin by imaging mass spectrometry. Proteomics 2014; 14:936-44. [PMID: 24453194 DOI: 10.1002/pmic.201300406] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 12/16/2013] [Accepted: 12/21/2013] [Indexed: 11/08/2022]
Abstract
Lipofuscin, an aging marker in the retinal pigment epithelium (RPE) associated with the development of age-related macular degeneration, is primarily characterized by its fluorescence. The most abundant component of RPE lipofuscin is N-retinylidene-N-retinylethanolamine (A2E) but its exact composition is not known due to the complexity of the RPE extract. In this study, we utilized MALDI imaging to find potential molecules responsible for lipofuscin fluorescence in RPE tissue from Abca4(-/-) , Sv129, and C57Bl6/J mice aged 2 and 6 months. To assert relationships, the individual images in the MALDI imaging datasets were correlated with lipofuscin fluorescence recorded from the same tissues following proper registration. Spatial correlation information, which is usually lost in bioanalytics, pinpointed a relatively small number of potential lipofuscin components. The comparison of four samples in each condition further limited the possibility of false positives and provided various new, age- and strain-specific targets. Validating the usefulness of the fluorescence-enhanced imaging strategy, many known adducts of A2E were identified in the short list of lipofuscin components. These results provided evidence that mass spectrometric imaging can be utilized as a tool to begin to identify the molecular substructure of clinically-relevant diagnostic information.
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Affiliation(s)
- Zsolt Ablonczy
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA
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27
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Zemski Berry KA, Gordon WC, Murphy RC, Bazan NG. Spatial organization of lipids in the human retina and optic nerve by MALDI imaging mass spectrometry. J Lipid Res 2013; 55:504-15. [PMID: 24367044 DOI: 10.1194/jlr.m044990] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
MALDI imaging mass spectrometry (IMS) was used to characterize lipid species within sections of human eyes. Common phospholipids that are abundant in most tissues were not highly localized and observed throughout the accessory tissue, optic nerve, and retina. Triacylglycerols were highly localized in accessory tissue, whereas sulfatide and plasmalogen glycerophosphoethanolamine (PE) lipids with a monounsaturated fatty acid were found enriched in the optic nerve. Additionally, several lipids were associated solely with the inner retina, photoreceptors, or retinal pigment epithelium (RPE); a plasmalogen PE lipid containing DHA (22:6), PE(P-18:0/22:6), was present exclusively in the inner retina, and DHA-containing glycerophosphatidylcholine (PC) and PE lipids were found solely in photoreceptors. PC lipids containing very long chain (VLC)-PUFAs were detected in photoreceptors despite their low abundance in the retina. Ceramide lipids and the bis-retinoid, N-retinylidene-N-retinylethanolamine, was tentatively identified and found only in the RPE. This MALDI IMS study readily revealed the location of many lipids that have been associated with degenerative retinal diseases. Complex lipid localization within retinal tissue provides a global view of lipid organization and initial evidence for specific functions in localized regions, offering opportunities to assess their significance in retinal diseases, such as macular degeneration, where lipids have been implicated in the disease process.
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Affiliation(s)
- Karin A Zemski Berry
- Department of Pharmacology, University of Colorado Denver, Aurora, CO 80045; and
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28
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Affiliation(s)
- Janet R Sparrow
- Departments of Ophthalmology and Pathology and Cell Biology, Columbia University, New York, New York
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Charbel Issa P, Barnard AR, Singh MS, Carter E, Jiang Z, Radu RA, Schraermeyer U, MacLaren RE. Fundus autofluorescence in the Abca4(-/-) mouse model of Stargardt disease--correlation with accumulation of A2E, retinal function, and histology. Invest Ophthalmol Vis Sci 2013; 54:5602-12. [PMID: 23761084 DOI: 10.1167/iovs.13-11688] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate fundus autofluorescence (AF) characteristics in the Abca4(-/-) mouse, an animal model for AMD and Stargardt disease, and to correlate findings with functional, structural, and biochemical assessments. METHODS Blue (488 nm) and near-infrared (790 nm) fundus AF images were quantitatively and qualitatively analyzed in pigmented Abca4(-/-) mice and wild type (WT) controls in vivo. Functional, structural, and biochemical assessments included electroretinography (ERG), light and electron microscopic analysis, and A2E quantification. All assessments were performed across age groups. RESULTS In Abca4(-/-) mice, lipofuscin-related 488 nm AF increased early in life with a ceiling effect after 6 months. This increase was first paralleled by an accumulation of typical lipofuscin granules in the retinal pigment epithelium (RPE). Later, lipofuscin and melanin granules decreased in number, whereas melanolipofuscin granules increased. This increase in melanolipofuscin granules paralleled an increase in melanin-related 790 nm AF. Old Abca4(-/-) mice revealed a flecked fundus AF pattern at both excitation wavelengths. The amount of A2E, a major lipofuscin component, increased 10- to 12-fold in 6- to 9-month-old Abca4(-/-) mice compared with controls, while 488 nm AF intensity only increased 2-fold. Despite pronounced lipofuscin accumulation in the RPE of Abca4(-/-) mice, ERG and histology showed a slow age-related thinning of the photoreceptor layer similar to WT controls up to 12 months. CONCLUSIONS Fundus AF can be used to monitor lipofuscin accumulation and melanin-related changes in vivo in mouse models of retinal disease. High RPE lipofuscin may not adversely affect retinal structure or function over prolonged time intervals, and melanin-related changes (melanolipofuscin formation) may occur before the decline in retinal function.
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Affiliation(s)
- Peter Charbel Issa
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, United Kingdom.
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30
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Ablonczy Z, Higbee D, Grey AC, Koutalos Y, Schey KL, Crouch RK. Similar molecules spatially correlate with lipofuscin and N-retinylidene-N-retinylethanolamine in the mouse but not in the human retinal pigment epithelium. Arch Biochem Biophys 2013; 539:196-202. [PMID: 23969078 DOI: 10.1016/j.abb.2013.08.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 08/08/2013] [Accepted: 08/10/2013] [Indexed: 01/08/2023]
Abstract
The accumulation of lipofuscin in the retinal pigment epithelium (RPE) has been implicated in the development of age-related macular degeneration (AMD) in humans. The exact composition of lipofuscin is not known but its best characterized component is N-retinylidene-N-retinylethanolamine (A2E), a byproduct of the retinoid visual cycle. Utilizing our recently developed matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS)-based technique to determine the spatial distribution of A2E, this study compares the relationships of lipofuscin fluorescence and A2E in the murine and human RPE on representative normal tissue. To identify molecules with similar spatial patterns, the images of A2E and lipofuscin were correlated with all the individual images in the MALDI-IMS dataset. In the murine RPE, there was a remarkable correlation between A2E and lipofuscin. In the human RPE, however, minimal correlation was detected. These results were reflected in the marked distinctions between the molecules that spatially correlated with the images of lipofuscin and A2E in the human RPE. While the distribution of murine lipofuscin showed highest similarities with some of the known A2E-adducts, the composition of human lipofuscin was significantly different. These results indicate that A2E metabolism may be altered in the human compared to the murine RPE.
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Affiliation(s)
- Zsolt Ablonczy
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, United States.
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31
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Ablonczy Z, Higbee D, Anderson DM, Dahrouj M, Grey AC, Gutierrez D, Koutalos Y, Schey KL, Hanneken A, Crouch RK. Lack of correlation between the spatial distribution of A2E and lipofuscin fluorescence in the human retinal pigment epithelium. Invest Ophthalmol Vis Sci 2013; 54:5535-42. [PMID: 23847313 DOI: 10.1167/iovs.13-12250] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The accumulation of lipofuscin in the RPE is a hallmark of aging in the eye. The best characterized component of lipofuscin is A2E, a bis-retinoid byproduct of the normal retinoid visual cycle, which exhibits a broad spectrum of cytotoxic effects in vitro. The purpose of our study was to correlate the distribution of lipofuscin and A2E across the human RPE. METHODS Lipofuscin fluorescence was imaged in flat-mounted RPE from human donors of various ages. The spatial distributions of A2E and its oxides were determined using matrix-assisted laser desorption-ionization imaging mass spectrometry (MALDI-IMS) on flat-mounted RPE tissue sections and retinal cross-sections. RESULTS Our data support the clinical observations of strong RPE fluorescence, increasing with age, in the central area of the RPE. However, there was no correlation between the distribution of A2E and lipofuscin, as the levels of A2E were highest in the far periphery and decreased toward the central region. High-resolution MALDI-IMS of retinal cross-sections confirmed the A2E localization data obtained in RPE flat-mounts. Singly- and doubly-oxidized A2E had distributions similar to A2E, but represented <10% of the A2E levels. CONCLUSIONS This report to our knowledge is the first description of the spatial distribution of A2E in the human RPE by imaging mass spectrometry. These data demonstrate that the accumulation of A2E is not responsible for the increase in lipofuscin fluorescence observed in the central RPE with aging.
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Affiliation(s)
- Zsolt Ablonczy
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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Norris JL, Caprioli RM. Analysis of tissue specimens by matrix-assisted laser desorption/ionization imaging mass spectrometry in biological and clinical research. Chem Rev 2013; 113:2309-42. [PMID: 23394164 PMCID: PMC3624074 DOI: 10.1021/cr3004295] [Citation(s) in RCA: 502] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Jeremy L. Norris
- National Research Resource for Imaging Mass Spectrometry, Mass Spectrometry Research Center, and Department of Biochemistry, Vanderbilt University School of Medicine, 9160 Medical Research Building III, 465 21st Avenue South, Nashville, TN 37232-8575
| | - Richard M. Caprioli
- National Research Resource for Imaging Mass Spectrometry, Mass Spectrometry Research Center, and Department of Biochemistry, Vanderbilt University School of Medicine, 9160 Medical Research Building III, 465 21st Avenue South, Nashville, TN 37232-8575
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33
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Anderson DMG, Mills D, Spraggins J, Lambert WS, Calkins DJ, Schey KL. High-resolution matrix-assisted laser desorption ionization-imaging mass spectrometry of lipids in rodent optic nerve tissue. Mol Vis 2013; 19:581-92. [PMID: 23559852 PMCID: PMC3611942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 03/17/2013] [Indexed: 11/21/2022] Open
Abstract
PURPOSE To develop a method for generating high spatial resolution (10 µm) matrix-assisted laser desorption ionization (MALDI) images of lipids in rodent optic nerve tissue. METHODS Ice-embedded optic nerve tissue from rats and mice were cryosectioned across the coronal and sagittal axes of the nerve fiber. Sections were thaw mounted on gold-coated MALDI plates and were washed with ammonium acetate to remove biologic salts before being coated in 2,5-dihydroxybenzoic acid by sublimation. MALDI images were generated in positive and negative ion modes at 10 µm spatial resolution. Lipid identification was performed with a high mass resolution Fourier transform ion cyclotron resonance mass spectrometer. RESULTS Several lipid species were observed with high signal intensity in MALDI images of optic nerve tissue. Several lipids were localized to specific structures including in the meninges surrounding the optic nerve and in the central neuronal tissue. Specifically, phosphatidylcholine species were observed throughout the nerve tissue in positive ion mode while sulfatide species were observed in high abundance in the meninges surrounding the optic nerve in negative ion mode. Accurate mass measurements and fragmentation using sustained off-resonance irradiation with a high mass resolution Fourier transform ion cyclotron resonance mass spectrometer instrument allowed for identification of lipid species present in the small structure of the optic nerve directly from tissue sections. CONCLUSIONS An optimized sample preparation method provides excellent sensitivity for lipid species present within optic nerve tissue. This allowed the laser spot size and fluence to be reduced to obtain a high spatial resolution of 10 µm. This new imaging modality can now be applied to determine spatial and molecular changes in optic nerve tissue with disease.
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Affiliation(s)
- David M. G. Anderson
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN,Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Daniel Mills
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN,Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Jeffrey Spraggins
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN,Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Wendi S. Lambert
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN
| | - David J. Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN
| | - Kevin L. Schey
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN,Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN
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de Oliveira DN, de Bona Sartor S, Ferreira MS, Catharino RR. Cosmetic Analysis Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI-MSI). MATERIALS 2013; 6:1000-1010. [PMID: 28809353 PMCID: PMC5512960 DOI: 10.3390/ma6031000] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/29/2013] [Accepted: 02/25/2013] [Indexed: 11/16/2022]
Abstract
A new "omic" platform-Cosmetomics-that proves to be extremely simple and effective in terms of sample preparation and readiness for data acquisition/interpretation is presented. This novel approach employing Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI-MSI) for cosmetic analysis has proven to readily identify and quantify compounds of interest. It also allows full control of all the production phases, as well as of the final product, by integration of both analytical and statistical data. This work has focused on products of daily use, namely nail polish, lipsticks and eyeliners of multiple brands sold in the worldwide market.
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Affiliation(s)
- Diogo Noin de Oliveira
- INNOVARE Biomarkers Lab, Medicine and Experimental Surgery Department, School of Medical Sciences, University of Campinas, Campinas 13083-877, Brazil.
| | - Sabrina de Bona Sartor
- INNOVARE Biomarkers Lab, Medicine and Experimental Surgery Department, School of Medical Sciences, University of Campinas, Campinas 13083-877, Brazil.
| | - Mônica Siqueira Ferreira
- INNOVARE Biomarkers Lab, Medicine and Experimental Surgery Department, School of Medical Sciences, University of Campinas, Campinas 13083-877, Brazil.
| | - Rodrigo Ramos Catharino
- INNOVARE Biomarkers Lab, Medicine and Experimental Surgery Department, School of Medical Sciences, University of Campinas, Campinas 13083-877, Brazil.
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Capozzi ME, Gordon AY, Penn JS, Jayagopal A. Molecular imaging of retinal disease. J Ocul Pharmacol Ther 2013; 29:275-86. [PMID: 23421501 DOI: 10.1089/jop.2012.0279] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Imaging of the eye plays an important role in ocular therapeutic discovery and evaluation in preclinical models and patients. Advances in ophthalmic imaging instrumentation have enabled visualization of the retina at an unprecedented resolution. These developments have contributed toward early detection of the disease, monitoring of disease progression, and assessment of the therapeutic response. These powerful technologies are being further harnessed for clinical applications by configuring instrumentation to detect disease biomarkers in the retina. These biomarkers can be detected either by measuring the intrinsic imaging contrast in tissue, or by the engineering of targeted injectable contrast agents for imaging of the retina at the cellular and molecular level. Such approaches have promise in providing a window on dynamic disease processes in the retina such as inflammation and apoptosis, enabling translation of biomarkers identified in preclinical and clinical studies into useful diagnostic targets. We discuss recently reported and emerging imaging strategies for visualizing diverse cell types and molecular mediators of the retina in vivo during health and disease, and the potential for clinical translation of these approaches.
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Affiliation(s)
- Megan E Capozzi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-8808, USA
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36
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Tang PH, Kono M, Koutalos Y, Ablonczy Z, Crouch RK. New insights into retinoid metabolism and cycling within the retina. Prog Retin Eye Res 2012; 32:48-63. [PMID: 23063666 DOI: 10.1016/j.preteyeres.2012.09.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Revised: 09/28/2012] [Accepted: 09/30/2012] [Indexed: 01/05/2023]
Abstract
The retinoid cycle is a series of biochemical reactions within the eye that is responsible for synthesizing the chromophore, 11-cis retinal, for visual function. The chromophore is bound to G-protein coupled receptors, opsins, within rod and cone photoreceptor cells forming the photosensitive visual pigments. Integral to the sustained function of photoreceptors is the continuous generation of chromophore by the retinoid cycle through two separate processes, one that supplies both rods and cones and another that exclusively supplies cones. Recent findings such as RPE65 localization within cones and the pattern of distribution of retinoid metabolites within mouse and human retinas have challenged previous proposed schemes. This review will focus on recent findings regarding the transport of retinoids, the mechanisms by which chromophore is supplied to both rods and cones, and the metabolism of retinoids within the posterior segment of the eye.
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Affiliation(s)
- Peter H Tang
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
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A novel source of methylglyoxal and glyoxal in retina: implications for age-related macular degeneration. PLoS One 2012; 7:e41309. [PMID: 22829938 PMCID: PMC3400616 DOI: 10.1371/journal.pone.0041309] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 06/19/2012] [Indexed: 11/19/2022] Open
Abstract
Aging of retinal pigment epithelial (RPE) cells of the eye is marked by accumulations of bisretinoid fluorophores; two of the compounds within this lipofuscin mixture are A2E and all-trans-retinal dimer. These pigments are implicated in pathological mechanisms involved in some vision-threatening disorders including age-related macular degeneration (AMD). Studies have shown that bisretinoids are photosensitive compounds that undergo photooxidation and photodegradation when irradiated with short wavelength visible light. Utilizing ultra performance liquid chromatography (UPLC) with electrospray ionization mass spectrometry (ESI-MS) we demonstrate that photodegradation of A2E and all-trans-retinal dimer generates the dicarbonyls glyoxal (GO) and methylglyoxal (MG), that are known to modify proteins by advanced glycation endproduct (AGE) formation. By extracellular trapping with aminoguanidine, we established that these oxo-aldehydes are released from irradiated A2E-containing RPE cells. Enzyme-linked immunosorbant assays (ELISA) revealed that the substrate underlying A2E-containing RPE was AGE-modified after irradiation. This AGE deposition was suppressed by prior treatment of the cells with aminoguanidine. AGE-modification causes structural and functional impairment of proteins. In chronic diseases such as diabetes and atherosclerosis, MG and GO modify proteins by non-enzymatic glycation and oxidation reactions. AGE-modified proteins are also components of drusen, the sub-RPE deposits that confer increased risk of AMD onset. These results indicate that photodegraded RPE bisretinoid is likely to be a previously unknown source of MG and GO in the eye.
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Abstract
The human eye is constantly exposed to sunlight and artificial lighting. Light transmission through the eye is fundamental to its unique biological functions of directing vision and circadian rhythm and therefore light absorbed by the eye must be benign. However, exposure to the very intense ambient radiation can pose a hazard particularly if the recipient is over 40 years of age. There are age-related changes in the endogenous (natural) chromophores (lipofuscin, A2E and all-trans-retinal derivatives) in the human retina that makes it more susceptible to visible light damage. Intense visible light sources that do not filter short blue visible light (400-440 nm) used for phototherapy of circadian imbalance (i.e. seasonal affective disorder) increase the risk for age-related light damage to the retina. Moreover, many drugs, dietary supplements, nanoparticles and diagnostic dyes (xenobiotics) absorb ocular light and have the potential to induce photodamage to the retina, leading to transient or permanent blinding disorders. This article will review the underlying reasons why visible light in general and short blue visible light in particular dramatically raises the risk of photodamage to the human retina.
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Affiliation(s)
- Albert R Wielgus
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
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39
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Boyer NP, Higbee D, Currin MB, Blakeley LR, Chen C, Ablonczy Z, Crouch RK, Koutalos Y. Lipofuscin and N-retinylidene-N-retinylethanolamine (A2E) accumulate in retinal pigment epithelium in absence of light exposure: their origin is 11-cis-retinal. J Biol Chem 2012; 287:22276-86. [PMID: 22570475 DOI: 10.1074/jbc.m111.329235] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The age-dependent accumulation of lipofuscin in the retinal pigment epithelium (RPE) has been associated with the development of retinal diseases, particularly age-related macular degeneration and Stargardt disease. A major component of lipofuscin is the bis-retinoid N-retinylidene-N-retinylethanolamine (A2E). The current model for the formation of A2E requires photoactivation of rhodopsin and subsequent release of all-trans-retinal. To understand the role of light exposure in the accumulation of lipofuscin and A2E, we analyzed RPEs and isolated rod photoreceptors from mice of different ages and strains, reared either in darkness or cyclic light. Lipofuscin levels were determined by fluorescence imaging, whereas A2E levels were quantified by HPLC and UV-visible absorption spectroscopy. The identity of A2E was confirmed by tandem mass spectrometry. Lipofuscin and A2E levels in the RPE increased with age and more so in the Stargardt model Abca4(-/-) than in the wild type strains 129/sv and C57Bl/6. For each strain, the levels of lipofuscin precursor fluorophores in dark-adapted rods and the levels and rates of increase of RPE lipofuscin and A2E were not different between dark-reared and cyclic light-reared animals. Both 11-cis- and all-trans-retinal generated lipofuscin-like fluorophores when added to metabolically compromised rod outer segments; however, it was only 11-cis-retinal that generated such fluorophores when added to metabolically intact rods. The results suggest that lipofuscin originates from the free 11-cis-retinal that is continuously supplied to the rod for rhodopsin regeneration and outer segment renewal. The physiological role of Abca4 may include the translocation of 11-cis-retinal complexes across the disk membrane.
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Affiliation(s)
- Nicholas P Boyer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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40
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Abstract
Accumulation of all-trans-retinal (all-trans-RAL), reactive vitamin A aldehyde, is one of the key factors in initiating retinal photodamage. This photodamage is characterized by progressive retinal cell death evoked by light exposure in both an acute and chronic fashion. Photoactivated rhodopsin releases all-trans-RAL, which is subsequently transported by ATP-binding cassette transporter 4 and reduced to all-trans-retinol by all-trans-retinol dehydrogenases located in photoreceptor cells. Any interruptions in the clearing of all-trans-RAL in the photoreceptors can cause an accumulation of this reactive aldehyde and its toxic condensation products. This accumulation may result in the manifestation of retinal dystrophy including human retinal degenerative diseases such as Stargardt's disease and age-related macular degeneration. Herein, we discuss the mechanisms of all-trans-RAL clearance in photoreceptor cells by sequential enzymatic reactions, the visual (retinoid) cycle, and potential molecular pathways of retinal photodamage. We also review recent imaging technologies to monitor retinal health status as well as novel therapeutic strategies preventing all-trans-RAL-associated retinal photodamage.
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Affiliation(s)
- Tadao Maeda
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, USA
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Sparrow JR, Ueda K, Zhou J. WITHDRAWN: Complement dysregulation in AMD: RPE-Bruch's membrane-choroid. Mol Aspects Med 2012:S0098-2997(12)00040-4. [PMID: 22542573 DOI: 10.1016/j.mam.2012.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 03/30/2012] [Indexed: 12/01/2022]
Abstract
The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.mam.2012.03.011. The duplicate article has therefore been withdrawn.
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Affiliation(s)
- Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
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Sparrow JR, Ueda K, Zhou J. Complement dysregulation in AMD: RPE-Bruch's membrane-choroid. Mol Aspects Med 2012; 33:436-45. [PMID: 22504022 DOI: 10.1016/j.mam.2012.03.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 03/30/2012] [Indexed: 01/01/2023]
Abstract
The question as to why the macula of the retina is prone to an aging disease (age-related macular degeneration) remains unanswered. This unmet challenge has implications since AMD accounts for approximately 54% of blindness in the USA (Swaroop, Chew, Bowes Rickman and Abecasis, 2009). While AMD has onset in the elder years, it likely develops over time. Genetic discovery to date has accounted for approximately 50% of the inheritable component of AMD. The polymorphism that has been most widely studied is the Y402H allele in the complement factor H gene. The implication of this genetic association is that in a subset of AMD cases, unregulated complement activation is permissive for AMD. Given that this gene variant results in an amino acid substitution, it is assumed that this change will have functional consequences although the precise mechanisms are still unknown. Genetic predisposition is not the only factor however, since in this complex disease there is substantial evidence that lifestyle factors such as diet and smoking contribute to risk. Here we provide an overview of current knowledge with respect to factors involved in AMD pathogenesis. Interwoven with these issues is a discussion of the significant role played by aging processes, some of which are unique to the retina and retinal pigment epithelium. One recurring theme is the potential for disease promotion by diverse types of oxidation products.
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Affiliation(s)
- Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA.
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43
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Ablonczy Z, Gutierrez DB, Grey AC, Schey KL, Crouch RK. Molecule-specific imaging and quantitation of A2E in the RPE. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 723:75-81. [PMID: 22183318 DOI: 10.1007/978-1-4614-0631-0_11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Zsolt Ablonczy
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA.
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44
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Sparrow JR, Gregory-Roberts E, Yamamoto K, Blonska A, Ghosh SK, Ueda K, Zhou J. The bisretinoids of retinal pigment epithelium. Prog Retin Eye Res 2011; 31:121-35. [PMID: 22209824 DOI: 10.1016/j.preteyeres.2011.12.001] [Citation(s) in RCA: 286] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 12/05/2011] [Accepted: 12/14/2011] [Indexed: 02/07/2023]
Abstract
The retina exhibits an inherent autofluorescence that is imaged ophthalmoscopically as fundus autofluorescence. In clinical settings, fundus autofluorescence examination aids in the diagnosis and follow-up of many retinal disorders. Fundus autofluorescence originates from the complex mixture of bisretinoid fluorophores that are amassed by retinal pigment epithelial (RPE) cells as lipofuscin. Unlike the lipofuscin found in other cell-types, this material does not form as a result of oxidative stress. Rather, the formation is attributable to non-enzymatic reactions of vitamin A aldehyde in photoreceptor cells; transfer to RPE occurs upon phagocytosis of photoreceptor outer segments. These fluorescent pigments accumulate even in healthy photoreceptor cells and are generated as a consequence of the light capturing function of the cells. Nevertheless, the formation of this material is accelerated in some retinal disorders including recessive Stargardt disease and ELOVL4-related retinal degeneration. As such, these bisretinoid side-products are implicated in the disease processes that threaten vision. In this article, we review our current understanding of the composition of RPE lipofuscin, the structural characteristics of the various bisretinoids, their related spectroscopic features and the biosynthetic pathways by which they form. We will revisit factors known to influence the extent of the accumulation and therapeutic strategies being used to limit bisretinoid formation. Given their origin from vitamin A aldehyde, an isomer of the visual pigment chromophore, it is not surprising that the bisretinoids of retina are light sensitive molecules. Accordingly, we will discuss recent findings that implicate the photodegradation of bisretinoid in the etiology of age-related macular degeneration.
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Affiliation(s)
- Janet R Sparrow
- Department of Ophthalmology, Columbia University, 630 W. 168th Street, New York, NY 10032, USA.
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