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Salimi Z, Afsharinasab M, Rostami M, Eshaghi Milasi Y, Mousavi Ezmareh SF, Sakhaei F, Mohammad-Sadeghipour M, Rasooli Manesh SM, Asemi Z. Iron chelators: as therapeutic agents in diseases. Ann Med Surg (Lond) 2024; 86:2759-2776. [PMID: 38694398 PMCID: PMC11060230 DOI: 10.1097/ms9.0000000000001717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 01/03/2024] [Indexed: 05/04/2024] Open
Abstract
The concentration of iron is tightly regulated, making it an essential element. Various cellular processes in the body rely on iron, such as oxygen sensing, oxygen transport, electron transfer, and DNA synthesis. Iron excess can be toxic because it participates in redox reactions that catalyze the production of reactive oxygen species and elevate oxidative stress. Iron chelators are chemically diverse; they can coordinate six ligands in an octagonal sequence. Because of the ability of chelators to trap essential metals, including iron, they may be involved in diseases caused by oxidative stress, such as infectious diseases, cardiovascular diseases, neurodegenerative diseases, and cancer. Iron-chelating agents, by tightly binding to iron, prohibit it from functioning as a catalyst in redox reactions and transfer iron and excrete it from the body. Thus, the use of iron chelators as therapeutic agents has received increasing attention. This review investigates the function of various iron chelators in treating iron overload in different clinical conditions.
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Affiliation(s)
- Zohreh Salimi
- Department of Clinical Biochemistry, Faculty of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan
| | - Mehdi Afsharinasab
- Department of Clinical Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran
| | - Mehdi Rostami
- Department of Clinical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad
| | - Yaser Eshaghi Milasi
- Department of Clinical Biochemistry, Faculty of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan
| | - Seyedeh Fatemeh Mousavi Ezmareh
- Department of Clinical Biochemistry, Faculty of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan
| | - Fariba Sakhaei
- Department of Clinical Biochemistry, Faculty of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan
| | - Maryam Mohammad-Sadeghipour
- Department of Clinical Biochemistry, Afzalipoor Faculty of Medicine, Kerman University of Medical Sciences, Kerman
| | | | - Zatollah Asemi
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Islamic Republic of Iran
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Liu D, Liu Z, Liao H, Chen ZS, Qin B. Ferroptosis as a potential therapeutic target for age-related macular degeneration. Drug Discov Today 2024; 29:103920. [PMID: 38369100 DOI: 10.1016/j.drudis.2024.103920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 02/20/2024]
Abstract
Cell death plays a crucial part in the process of age-related macular degeneration (AMD), but its mechanisms remain elusive. Accumulating evidence suggests that ferroptosis, a novel form of regulatory cell death characterized by iron-dependent accumulation of lipid hydroperoxides, has a crucial role in the pathogenesis of AMD. Numerous studies have suggested that ferroptosis participates in the degradation of retinal cells and accelerates the progression of AMD. Furthermore, inhibitors of ferroptosis exhibit notable protective effects in AMD, underscoring the significance of ferroptosis as a pivotal mechanism in the death of retinal cells during the process of AMD. This review aims to summarize the molecular mechanisms of ferroptosis in AMD, enumerate potential inhibitors and discuss the challenges and future opportunities associated with targeting ferroptosis as a therapeutic strategy, providing important information references and insights for the prevention and treatment of AMD.
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Affiliation(s)
- Dongcheng Liu
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China
| | - Ziling Liu
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China
| | - Hongxia Liao
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China
| | - Zhe-Sheng Chen
- College of Pharmacy and Health Sciences, St. John's University, Queens, New York, USA.
| | - Bo Qin
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China; Aier Eye Hospital, Tianjin University, Tianjin, China.
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3
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Kannan RM, Pitha I, Parikh KS. A new era in posterior segment ocular drug delivery: Translation of systemic, cell-targeted, dendrimer-based therapies. Adv Drug Deliv Rev 2023; 200:115005. [PMID: 37419213 DOI: 10.1016/j.addr.2023.115005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/16/2023] [Accepted: 07/04/2023] [Indexed: 07/09/2023]
Abstract
Vision impairment and loss due to posterior segment ocular disorders, including age-related macular degeneration and diabetic retinopathy, are a rapidly growing cause of disability globally. Current treatments consist primarily of intravitreal injections aimed at preventing disease progression and characterized by high cost and repeated clinic visits. Nanotechnology provides a promising platform for drug delivery to the eye, with potential to overcome anatomical and physiological barriers to provide safe, effective, and sustained treatment modalities. However, there are few nanomedicines approved for posterior segment disorders, and fewer that target specific cells or that are compatible with systemic administration. Targeting cell types that mediate these disorders via systemic administration may unlock transformative opportunities for nanomedicine and significantly improve patient access, acceptability, and outcomes. We highlight the development of hydroxyl polyamidoamine dendrimer-based therapeutics that demonstrate ligand-free cell targeting via systemic administration and are under clinical investigation for treatment of wet age-related macular degeneration.
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Affiliation(s)
- Rangaramanujam M Kannan
- Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Departments of Chemical and Biomolecular Engineering and Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA.
| | - Ian Pitha
- Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kunal S Parikh
- Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Center for Bioengineering Innovation & Design, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Anderson BD, Lee T, Bell B, Song Y, Dunaief JL. Low ceruloplasmin levels exacerbate retinal degeneration in a hereditary hemochromatosis model. Dis Model Mech 2023; 16:dmm050226. [PMID: 37439255 PMCID: PMC10354715 DOI: 10.1242/dmm.050226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/09/2023] [Indexed: 07/14/2023] Open
Abstract
In a previous report, a 39-year-old patient with high serum iron levels from hereditary hemochromatosis (HH) was diagnosed with a form of retinal degeneration called bull's eye maculopathy. This is atypical for patients with HH, so it was theorized that the low serum levels of ferroxidase ceruloplasmin (CP) of this patient coupled with the high iron levels led to the retinal degeneration. CP, by oxidizing iron from its ferrous to ferric form, helps prevent the oxidative damage caused by ferrous iron. To test this, a hepcidin knockout (KO) mouse model of HH was combined with Cp KO to test whether the combination would lead to more severe retinal degeneration. Monthly in vivo retinal images were acquired and, after 11 months, mice were euthanized for further analyses. Both heterozygous and homozygous Cp KO increased the rate and severity of retinal degeneration. These results demonstrate the protective role of CP, which is most likely owing to its ferroxidase activity. The findings suggest that CP levels may influence the severity of retinal degeneration, especially in individuals with high serum iron.
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Affiliation(s)
- Brandon D. Anderson
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Timothy Lee
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Brent Bell
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ying Song
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Joshua L. Dunaief
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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Zhang KR, Jankowski CSR, Marshall R, Nair R, Más Gómez N, Alnemri A, Liu Y, Erler E, Ferrante J, Song Y, Bell BA, Baumann BH, Sterling J, Anderson B, Foshe S, Roof J, Fazelinia H, Spruce LA, Chuang JZ, Sung CH, Dhingra A, Boesze-Battaglia K, Chavali VRM, Rabinowitz JD, Mitchell CH, Dunaief JL. Oxidative stress induces lysosomal membrane permeabilization and ceramide accumulation in retinal pigment epithelial cells. Dis Model Mech 2023; 16:dmm050066. [PMID: 37401371 PMCID: PMC10399446 DOI: 10.1242/dmm.050066] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 06/23/2023] [Indexed: 07/05/2023] Open
Abstract
Oxidative stress has been implicated in the pathogenesis of age-related macular degeneration, the leading cause of blindness in older adults, with retinal pigment epithelium (RPE) cells playing a key role. To better understand the cytotoxic mechanisms underlying oxidative stress, we used cell culture and mouse models of iron overload, as iron can catalyze reactive oxygen species formation in the RPE. Iron-loading of cultured induced pluripotent stem cell-derived RPE cells increased lysosomal abundance, impaired proteolysis and reduced the activity of a subset of lysosomal enzymes, including lysosomal acid lipase (LIPA) and acid sphingomyelinase (SMPD1). In a liver-specific Hepc (Hamp) knockout murine model of systemic iron overload, RPE cells accumulated lipid peroxidation adducts and lysosomes, developed progressive hypertrophy and underwent cell death. Proteomic and lipidomic analyses revealed accumulation of lysosomal proteins, ceramide biosynthetic enzymes and ceramides. The proteolytic enzyme cathepsin D (CTSD) had impaired maturation. A large proportion of lysosomes were galectin-3 (Lgals3) positive, suggesting cytotoxic lysosomal membrane permeabilization. Collectively, these results demonstrate that iron overload induces lysosomal accumulation and impairs lysosomal function, likely due to iron-induced lipid peroxides that can inhibit lysosomal enzymes.
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Affiliation(s)
- Kevin R. Zhang
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Connor S. R. Jankowski
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Rayna Marshall
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rohini Nair
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Néstor Más Gómez
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ahab Alnemri
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yingrui Liu
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elizabeth Erler
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Julia Ferrante
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brent A. Bell
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bailey H. Baumann
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jacob Sterling
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brandon Anderson
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sierra Foshe
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jennifer Roof
- CHOP-PENN Proteomics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Hossein Fazelinia
- CHOP-PENN Proteomics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Lynn A. Spruce
- CHOP-PENN Proteomics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Jen-Zen Chuang
- Department of Ophthalmology, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Ching-Hwa Sung
- Department of Ophthalmology, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Anuradha Dhingra
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Venkata R. M. Chavali
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joshua D. Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Claire H. Mitchell
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joshua L. Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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Sterling JK, Baumann B, Foshe S, Voigt A, Guttha S, Alnemri A, McCright SJ, Li M, Zauhar RJ, Montezuma SR, Kapphahn RJ, Chavali VRM, Hill DA, Ferrington DA, Stambolian D, Mullins RF, Merrick D, Dunaief JL. Inflammatory adipose activates a nutritional immunity pathway leading to retinal dysfunction. Cell Rep 2022; 39:110942. [PMID: 35705048 PMCID: PMC9248858 DOI: 10.1016/j.celrep.2022.110942] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 01/24/2022] [Accepted: 05/20/2022] [Indexed: 11/21/2022] Open
Abstract
Age-related macular degeneration (AMD), the leading cause of irreversible blindness among Americans over 50, is characterized by dysfunction and death of retinal pigment epithelial (RPE) cells. The RPE accumulates iron in AMD, and iron overload triggers RPE cell death in vitro and in vivo. However, the mechanism of RPE iron accumulation in AMD is unknown. We show that high-fat-diet-induced obesity, a risk factor for AMD, drives systemic and local inflammatory circuits upregulating interleukin-1β (IL-1β). IL-1β upregulates RPE iron importers and downregulates iron exporters, causing iron accumulation, oxidative stress, and dysfunction. We term this maladaptive, chronic activation of a nutritional immunity pathway the cellular iron sequestration response (CISR). RNA sequencing (RNA-seq) analysis of choroid and retina from human donors revealed that hallmarks of this pathway are present in AMD microglia and macrophages. Together, these data suggest that inflamed adipose tissue, through the CISR, can lead to RPE pathology in AMD.
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Affiliation(s)
- Jacob K Sterling
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Medical Scientist Training Program, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Bailey Baumann
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Medical Scientist Training Program, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Sierra Foshe
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Andrew Voigt
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA; Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Samyuktha Guttha
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ahab Alnemri
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Sam J McCright
- Medical Scientist Training Program, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Allergy and Immunology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Mingyao Li
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Randy J Zauhar
- Department of Chemistry & Biochemistry, University of the Sciences, Philadelphia, PA 19104, USA
| | - Sandra R Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Rebecca J Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Venkata R M Chavali
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - David A Hill
- Division of Allergy and Immunology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Institute of Diabetes, Obesity and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Dwight Stambolian
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Robert F Mullins
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA; Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - David Merrick
- Department of Medicine, Division of Endocrinology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Institute of Diabetes, Obesity and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Joshua L Dunaief
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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Liu Y, Baumann B, Song Y, Zhang K, Sterling JK, Lakhal-Littleton S, Kozmik Z, Su G, Dunaief JL. Minimal effect of conditional ferroportin KO in the neural retina implicates ferrous iron in retinal iron overload and degeneration. Exp Eye Res 2022; 218:108988. [PMID: 35202704 PMCID: PMC9050912 DOI: 10.1016/j.exer.2022.108988] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/07/2022] [Accepted: 02/14/2022] [Indexed: 02/09/2023]
Abstract
Iron-induced oxidative stress can cause or exacerbate retinal degenerative diseases. Retinal iron overload has been reported in several mouse disease models with systemic or neural retina-specific knockout (KO) of homologous ferroxidases ceruloplasmin (Cp) and hephaestin (Heph). Cp and Heph can potentiate ferroportin (Fpn) mediated cellular iron export. Here, we used retina-specific Fpn KO mice to test the hypothesis that retinal iron overload in Cp/Heph DKO mice is caused by impaired iron export from neurons and glia. Surprisingly, there was no indication of retinal iron overload in retina-specific Fpn KO mice: the mRNA levels of transferrin receptor in the retina were not altered at 7-10-months age. Consistent with this, levels and localization of ferritin light chain were unchanged. To "stress the system", we injected iron intraperitoneally into Fpn KO mice with or without Cp KO. Only mice with both retina-specific Fpn KO and Cp KO had modestly elevated retinal iron levels. These results suggest that impaired iron export through Fpn is not sufficient to explain the retinal iron overload in Cp/Heph DKO mice. An increase in the levels of retinal ferrous iron caused by the absence of these ferroxidases, followed by uptake into cells by ferrous iron importers, is most likely necessary.
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Affiliation(s)
- Yingrui Liu
- Department of Ophthalmology, The Second Hospital of Jilin University, No. 218 Ziqiang Street, Changchun, Jilin, China,F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, USA
| | - Bailey Baumann
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, USA
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, USA
| | - Kevin Zhang
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, USA
| | - Jacob K. Sterling
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, USA
| | - Samira Lakhal-Littleton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Zbynek Kozmik
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Academy of Sciences of the Czech Republic (ASCR), Prague, Czech Republic
| | - Guanfang Su
- Department of Ophthalmology, The Second Hospital of Jilin University, No. 218 Ziqiang Street, Changchun, Jilin, China,Co-correspondence authors: Correspondence to: Joshua L. Dunaief, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA. Tel: +1 215 898 5235, , Guanfang Su, Department of Ophthalmology, The Second Hospital of Jilin University, No. 218 Ziqiang Street, Changchun, Jilin, 130041, China. Tel: +86 13843091955,
| | - Joshua L. Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, USA,Co-correspondence authors: Correspondence to: Joshua L. Dunaief, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA. Tel: +1 215 898 5235, , Guanfang Su, Department of Ophthalmology, The Second Hospital of Jilin University, No. 218 Ziqiang Street, Changchun, Jilin, 130041, China. Tel: +86 13843091955,
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8
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Tebbe L, Sakthivel H, Makia MS, Kakakhel M, Conley SM, Al-Ubaidi MR, Naash MI. Prph2 disease mutations lead to structural and functional defects in the RPE. FASEB J 2022; 36:e22284. [PMID: 35344225 PMCID: PMC10599796 DOI: 10.1096/fj.202101562rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 02/28/2022] [Accepted: 03/17/2022] [Indexed: 11/11/2022]
Abstract
Prph2 is a photoreceptor-specific tetraspanin with an essential role in the structure and function of photoreceptor outer segments. PRPH2 mutations cause a multitude of retinal diseases characterized by the degeneration of photoreceptors as well as defects in neighboring tissues such as the RPE. While extensive research has analyzed photoreceptors, less attention has been paid to these secondary defects. Here, we use different Prph2 disease models to evaluate the damage of the RPE arising from photoreceptor defects. In Prph2 disease models, the RPE exhibits structural abnormalities and cell loss. Furthermore, RPE functional defects are observed, including impaired clearance of phagocytosed outer segment material and increased microglia activation. The severity of RPE damage is different between models, suggesting that the different abnormal outer segment structures caused by Prph2 disease mutations lead to varying degrees of RPE stress and thus influence the clinical phenotype observed in patients.
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Affiliation(s)
- Lars Tebbe
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Haarthi Sakthivel
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Mustafa S. Makia
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
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9
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Liu Y, Bell BA, Song Y, Zhang K, Anderson B, Axelsen PH, Bohannan W, Agbaga M, Park HG, James G, Brenna JT, Schmidt K, Dunaief JL, Shchepinov MS. Deuterated docosahexaenoic acid protects against oxidative stress and geographic atrophy-like retinal degeneration in a mouse model with iron overload. Aging Cell 2022; 21:e13579. [PMID: 35257475 PMCID: PMC9009113 DOI: 10.1111/acel.13579] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/24/2022] [Accepted: 02/11/2022] [Indexed: 01/03/2023] Open
Abstract
Oxidative stress plays a central role in age-related macular degeneration (AMD). Iron, a potent generator of hydroxyl radicals through the Fenton reaction, has been implicated in AMD. One easily oxidized molecule is docosahexaenoic acid (DHA), the most abundant polyunsaturated fatty acid in photoreceptor membranes. Oxidation of DHA produces toxic oxidation products including carboxyethylpyrrole (CEP) adducts, which are increased in the retinas of AMD patients. In this study, we hypothesized that deuterium substitution on the bis-allylic sites of DHA in photoreceptor membranes could prevent iron-induced retinal degeneration by inhibiting oxidative stress and lipid peroxidation. Mice were fed with either DHA deuterated at the oxidation-prone positions (D-DHA) or control natural DHA and then given an intravitreal injection of iron or control saline. Orally administered D-DHA caused a dose-dependent increase in D-DHA levels in the neural retina and retinal pigment epithelium (RPE) as measured by mass spectrometry. At 1 week after iron injection, D-DHA provided nearly complete protection against iron-induced retinal autofluorescence and retinal degeneration, as determined by in vivo imaging, electroretinography, and histology. Iron injection resulted in carboxyethylpyrrole conjugate immunoreactivity in photoreceptors and RPE in mice fed with natural DHA but not D-DHA. Quantitative PCR results were consistent with iron-induced oxidative stress, inflammation, and retinal cell death in mice fed with natural DHA but not D-DHA. Taken together, our findings suggest that DHA oxidation is central to the pathogenesis of iron-induced retinal degeneration. They also provide preclinical evidence that dosing with D-DHA could be a viable therapeutic strategy for retinal diseases involving oxidative stress.
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Affiliation(s)
- Yingrui Liu
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Brent A. Bell
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Ying Song
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Kevin Zhang
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Brandon Anderson
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Paul H. Axelsen
- Department of PharmacologyPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Whitney Bohannan
- Departments of Cell Biology and OphthalmologyUniversity of Oklahoma Health Sciences Center and the Dean McGee Eye InstituteOklahoma CityOklahomaUSA
| | - Martin‐Paul Agbaga
- Departments of Cell Biology and OphthalmologyUniversity of Oklahoma Health Sciences Center and the Dean McGee Eye InstituteOklahoma CityOklahomaUSA
| | - Hui Gyu Park
- Dell Pediatric Research InstituteUniversity of Texas at AustinAustinTexasUSA
| | - Genevieve James
- Dell Pediatric Research InstituteUniversity of Texas at AustinAustinTexasUSA
| | - J. Thomas Brenna
- Dell Pediatric Research InstituteUniversity of Texas at AustinAustinTexasUSA
| | | | - Joshua L. Dunaief
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
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10
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Kim SY, Qian H. Comparison between sodium iodate and lipid peroxide murine models of age-related macular degeneration for drug evaluation-a narrative review. ANNALS OF EYE SCIENCE 2022; 7:8. [PMID: 37622161 PMCID: PMC10448775 DOI: 10.21037/aes-21-25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
Objective In this review, non-transgenic models of age-related macular degeneration (AMD) are discussed, with focuses on murine retinal degeneration induced by sodium iodate and lipid peroxide (HpODE) as preclinical study platforms. Background AMD is the most common cause of vision loss in a world with an increasingly aging population. The major phenotypes of early and intermediate AMD are increased drusen and autofluorescence, Müller glia activation, infiltrated subretinal microglia and inward moving retinal pigment epithelium cells. Intermediate AMD may progress to advanced AMD, characterized by geography atrophy and/or choroidal neovascularization. Various transgenic and non-transgenic animal models related to retinal degeneration have been generated to investigate AMD pathogenesis and pathobiology, and have been widely used as potential therapeutic evaluation platforms. Methods Two retinal degeneration murine models induced by sodium iodate and HpODE are described. Distinct pathological features and procedures of these two models are compared. In addition, practical protocol and material preparation and assessment methods are elaborated. Conclusion Retina degeneration induced by sodium iodate and HpODE in mouse eye resembles many clinical aspects of human AMD and complimentary to the existent other animal models. However, standardization of procedure and assessment protocols is needed for preclinical studies. Further studies of HpODE on different routes, doses and species will be valuable for the future extensive use. Despite many merits of murine studies, differences between murine and human should be always considered.
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Affiliation(s)
- Soo-Young Kim
- Department of Pharmaceutics, Department of Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University of Medicine, Baltimore, MD, 21287, USA
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
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11
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Shahandeh A, Bui BV, Finkelstein DI, Nguyen CTO. Effects of Excess Iron on the Retina: Insights From Clinical Cases and Animal Models of Iron Disorders. Front Neurosci 2022; 15:794809. [PMID: 35185447 PMCID: PMC8851357 DOI: 10.3389/fnins.2021.794809] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/17/2021] [Indexed: 01/19/2023] Open
Abstract
Iron plays an important role in a wide range of metabolic pathways that are important for neuronal health. Excessive levels of iron, however, can promote toxicity and cell death. An example of an iron overload disorder is hemochromatosis (HH) which is a genetic disorder of iron metabolism in which the body’s ability to regulate iron absorption is altered, resulting in iron build-up and injury in several organs. The retina was traditionally assumed to be protected from high levels of systemic iron overload by the blood-retina barrier. However, recent data shows that expression of genes that are associated with HH can disrupt retinal iron metabolism. Thus, the effects of iron overload on the retina have become an area of research interest, as excessively high levels of iron are implicated in several retinal disorders, most notably age–related macular degeneration. This review is an effort to highlight risk factors for excessive levels of systemic iron build-up in the retina and its potential impact on the eye health. Information is integrated across clinical and preclinical animal studies to provide insights into the effects of systemic iron loading on the retina.
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Affiliation(s)
- Ali Shahandeh
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Bang V. Bui
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - David I. Finkelstein
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Christine T. O. Nguyen
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
- *Correspondence: Christine T. O. Nguyen,
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12
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Liu Y, Bell BA, Song Y, Kim HJ, Sterling JK, Kim BJ, Poli M, Guo M, Zhang K, Rao A, Sparrow JR, Su G, Dunaief JL. Intraocular iron injection induces oxidative stress followed by elements of geographic atrophy and sympathetic ophthalmia. Aging Cell 2021; 20:e13490. [PMID: 34626070 PMCID: PMC8590099 DOI: 10.1111/acel.13490] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/24/2021] [Accepted: 09/14/2021] [Indexed: 01/24/2023] Open
Abstract
Iron has been implicated in the pathogenesis of age‐related retinal diseases, including age‐related macular degeneration (AMD). Previous work showed that intravitreal (IVT) injection of iron induces acute photoreceptor death, lipid peroxidation, and autofluorescence (AF). Herein, we extend this work, finding surprising chronic features of the model: geographic atrophy and sympathetic ophthalmia. We provide new mechanistic insights derived from focal AF in the photoreceptors, quantification of bisretinoids, and localization of carboxyethyl pyrrole, an oxidized adduct of docosahexaenoic acid associated with AMD. In mice given IVT ferric ammonium citrate (FAC), RPE died in patches that slowly expanded at their borders, like human geographic atrophy. There was green AF in the photoreceptor ellipsoid, a mitochondria‐rich region, 4 h after injection, followed later by gold AF in rod outer segments, RPE and subretinal myeloid cells. The green AF signature is consistent with flavin adenine dinucleotide, while measured increases in the bisretinoid all‐trans‐retinal dimer are consistent with the gold AF. FAC induced formation carboxyethyl pyrrole accumulation first in photoreceptors, then in RPE and myeloid cells. Quantitative PCR on neural retina and RPE indicated antioxidant upregulation and inflammation. Unexpectedly, reminiscent of sympathetic ophthalmia, autofluorescent myeloid cells containing abundant iron infiltrated the saline‐injected fellow eyes only if the contralateral eye had received IVT FAC. These findings provide mechanistic insights into the potential toxicity caused by AMD‐associated retinal iron accumulation. The mouse model will be useful for testing antioxidants, iron chelators, ferroptosis inhibitors, anti‐inflammatory medications, and choroidal neovascularization inhibitors.
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Affiliation(s)
- Yingrui Liu
- Department of Ophthalmology The Second Hospital of Jilin University Changchun China
- F.M. Kirby Center for Molecular Ophthalmology Scheie Eye Institute Perelman School of Medicine at the University of Pennsylvania Philadelphia Pennsylvania USA
| | - Brent A. Bell
- F.M. Kirby Center for Molecular Ophthalmology Scheie Eye Institute Perelman School of Medicine at the University of Pennsylvania Philadelphia Pennsylvania USA
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology Scheie Eye Institute Perelman School of Medicine at the University of Pennsylvania Philadelphia Pennsylvania USA
| | - Hye J. Kim
- Department of Ophthalmology Harkness Eye Institute Columbia University Medical Center New York New York USA
| | - Jacob K. Sterling
- F.M. Kirby Center for Molecular Ophthalmology Scheie Eye Institute Perelman School of Medicine at the University of Pennsylvania Philadelphia Pennsylvania USA
| | - Benjamin J. Kim
- Department of Ophthalmology Scheie Eye Institute University of Pennsylvania Philadelphia Pennsylvania USA
| | - Maura Poli
- Department of Molecular and Translational Medicine University of Brescia Brescia Italy
| | - Michelle Guo
- F.M. Kirby Center for Molecular Ophthalmology Scheie Eye Institute Perelman School of Medicine at the University of Pennsylvania Philadelphia Pennsylvania USA
| | - Kevin Zhang
- F.M. Kirby Center for Molecular Ophthalmology Scheie Eye Institute Perelman School of Medicine at the University of Pennsylvania Philadelphia Pennsylvania USA
| | - Aditya Rao
- Department of Molecular Life Science University of Pennsylvania Philadelphia Pennsylvania USA
| | - Janet R. Sparrow
- Department of Ophthalmology Harkness Eye Institute Columbia University Medical Center New York New York USA
| | - Guanfang Su
- Department of Ophthalmology The Second Hospital of Jilin University Changchun China
| | - Joshua L. Dunaief
- F.M. Kirby Center for Molecular Ophthalmology Scheie Eye Institute Perelman School of Medicine at the University of Pennsylvania Philadelphia Pennsylvania USA
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13
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Ashok A, Chaudhary S, Wise AS, Rana NA, McDonald D, Kritikos AE, Lindner E, Singh N. Release of Iron-Loaded Ferritin in Sodium Iodate-Induced Model of Age Related Macular Degeneration: An In-Vitro and In-Vivo Study. Antioxidants (Basel) 2021; 10:1253. [PMID: 34439501 PMCID: PMC8389213 DOI: 10.3390/antiox10081253] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/20/2021] [Accepted: 07/30/2021] [Indexed: 11/17/2022] Open
Abstract
To evaluate the role of iron in sodium iodate (NaIO3)-induced model of age-related macular degeneration (AMD) in ARPE-19 cells in-vitro and in mouse models in-vivo. ARPE-19 cells, a human retinal pigment epithelial cell line, was exposed to 10 mM NaIO3 for 24 h, and the expression and localization of major iron modulating proteins was evaluated by Western blotting (WB) and immunostaining. Synthesis and maturation of cathepsin-D (cat-D), a lysosomal enzyme, was evaluated by quantitative reverse-transcriptase polymerase chain reaction (RT-qPCR) and WB, respectively. For in-vivo studies, C57BL/6 mice were injected with 40 mg/kg mouse body weight of NaIO3 intraperitoneally, and their retina was evaluated after 3 weeks as above. NaIO3 induced a 10-fold increase in ferritin in ARPE-19 cells, which co-localized with LC3II, an autophagosomal marker, and LAMP-1, a lysosomal marker. A similar increase in ferritin was noted in retinal lysates and retinal sections of NaIO3-injected mice by WB and immunostaining. Impaired synthesis and maturation of cat-D was also noted. Accumulated ferritin was loaded with iron, and released from retinal pigmented epithelial (RPE) cells in Perls' and LAMP-1 positive vesicles. NaIO3 impairs lysosomal degradation of ferritin by decreasing the transcription and maturation of cat-D in RPE cells. Iron-loaded ferritin accumulates in lysosomes and is released in lysosomal membrane-enclosed vesicles to the extracellular milieu. Accumulation of ferritin in RPE cells and fusion of ferritin-containing vesicles with adjacent photoreceptor cells is likely to create an iron overload, compromising their viability. Moreover, reduced activity of cat-D is likely to promote accumulation of other cellular debris in lysosomal vesicles, contributing to AMD-like pathology.
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Affiliation(s)
- Ajay Ashok
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; (A.A.); (S.C.); (A.S.W.); (N.A.R.); (D.M.); (A.E.K.)
| | - Suman Chaudhary
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; (A.A.); (S.C.); (A.S.W.); (N.A.R.); (D.M.); (A.E.K.)
| | - Aaron S. Wise
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; (A.A.); (S.C.); (A.S.W.); (N.A.R.); (D.M.); (A.E.K.)
| | - Neil A. Rana
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; (A.A.); (S.C.); (A.S.W.); (N.A.R.); (D.M.); (A.E.K.)
| | - Dallas McDonald
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; (A.A.); (S.C.); (A.S.W.); (N.A.R.); (D.M.); (A.E.K.)
| | - Alexander E. Kritikos
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; (A.A.); (S.C.); (A.S.W.); (N.A.R.); (D.M.); (A.E.K.)
| | - Ewald Lindner
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria;
| | - Neena Singh
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; (A.A.); (S.C.); (A.S.W.); (N.A.R.); (D.M.); (A.E.K.)
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14
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Zhao T, Guo X, Sun Y. Iron Accumulation and Lipid Peroxidation in the Aging Retina: Implication of Ferroptosis in Age-Related Macular Degeneration. Aging Dis 2021; 12:529-551. [PMID: 33815881 PMCID: PMC7990372 DOI: 10.14336/ad.2020.0912] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/12/2020] [Indexed: 01/19/2023] Open
Abstract
Iron is an essential component in many biological processes in the human body. It is critical for the visual phototransduction cascade in the retina. However, excess iron can be toxic. Iron accumulation and reduced efficiency of intracellular antioxidative defense systems predispose the aging retina to oxidative stress-induced cell death. Age-related macular degeneration (AMD) is characterized by retinal iron accumulation and lipid peroxidation. The mechanisms underlying AMD include oxidative stress-mediated death of retinal pigment epithelium (RPE) cells and subsequent death of retinal photoreceptors. Understanding the mechanism of the disruption of iron and redox homeostasis in the aging retina and AMD is crucial to decipher these mechanisms of cell death and AMD pathogenesis. The mechanisms of retinal cell death in AMD are an area of active investigation; previous studies have proposed several types of cell death as major mechanisms. Ferroptosis, a newly discovered programmed cell death pathway, has been associated with the pathogenesis of several neurodegenerative diseases. Ferroptosis is initiated by lipid peroxidation and is characterized by iron-dependent accumulation. In this review, we provide an overview of the mechanisms of iron accumulation and lipid peroxidation in the aging retina and AMD, with an emphasis on ferroptosis.
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Affiliation(s)
- Tantai Zhao
- 1Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China.,2Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan, China
| | - Xiaojian Guo
- 1Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China.,2Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan, China
| | - Yun Sun
- 1Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China.,2Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan, China
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15
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Ghaffarieh A, Ciolino JB. Potential of Application of Iron Chelating Agents in Ophthalmic Diseases. Semin Ophthalmol 2021; 36:157-161. [PMID: 33621147 DOI: 10.1080/08820538.2021.1887900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The investigations discussed in this review indicate that iron may exacerbate different eye diseases. Therefore, it is plausible that reducing cellular or body iron stores could influence disease pathogenesis, so it is logical to consider the iron chelators' potential protective role in the various ophthalmic diseases in the form of topical eye drops or slow releasing injectable compounds as an adjuvant treatment.
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Affiliation(s)
- Alireza Ghaffarieh
- Ophthalmology, Cornea, External Disease & Refractive Surgery Fellow, Massachusetts Eye and Ear Infirmary, Harvard University, USA
| | - Joseph B Ciolino
- Ophthalmology, Associate Professor of Ophthalmology, Harvard Medical School Mass. Eye and Ear/Schepens Eye Research Institute, USA
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16
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ASSOCIATION BETWEEN ORAL IRON SUPPLEMENTATION AND RETINAL OR SUBRETINAL HEMORRHAGE IN THE COMPARISON OF AGE-RELATED MACULAR DEGENERATION TREATMENT TRIALS. Retina 2020; 39:1965-1972. [PMID: 30157115 DOI: 10.1097/iae.0000000000002295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
PURPOSE Because patients often take iron supplements without medical indication, and iron can accumulate in vascular endothelial cells, the authors evaluated the association of oral iron supplementation with retinal/subretinal hemorrhage in patients with neovascular age-related macular degeneration. METHODS A post hoc secondary data analysis of comparison of age-related macular degeneration treatments trials was performed. Participants were interviewed for use of oral iron supplements. Trained readers evaluated retinal/subretinal hemorrhage in baseline fundus photographs. Adjusted odds ratios from multivariate logistic regression models assessed the association between iron use and baseline hemorrhage adjusted by age, sex, smoking, hypertension, anemia, and use of antiplatelet/anticoagulant drugs. RESULTS Among 1,165 participants, baseline retinal/subretinal hemorrhage was present in the study eye in 71% of 181 iron users and in 61% of 984 participants without iron use (adjusted odds ratio = 1.47, P = 0.04), and the association was dose dependent (adjusted linear trend P = 0.048). Iron use was associated with hemorrhage in participants with hypertension (adjusted odds ratio = 1.87, P = 0.006) but not without hypertension. The association of iron use with hemorrhage remained significant among hypertensive participants without anemia (adjusted odds ratio = 1.85, P = 0.02). CONCLUSION Among participants of comparison of age-related macular degeneration treatments trials, the use of oral iron supplements was associated with retinal/subretinal hemorrhage in a dose-response manner. Unindicated iron supplementation may be detrimental in patients with wet age-related macular degeneration.
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17
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Retinal Degeneration and Alzheimer's Disease: An Evolving Link. Int J Mol Sci 2020; 21:ijms21197290. [PMID: 33023198 PMCID: PMC7582766 DOI: 10.3390/ijms21197290] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/15/2020] [Accepted: 09/25/2020] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) and glaucoma are degenerative conditions of the retina and a significant cause of irreversible blindness in developed countries. Alzheimer’s disease (AD), the most common dementia of the elderly, is often associated with AMD and glaucoma. The cardinal features of AD include extracellular accumulation of amyloid β (Aβ) and intracellular deposits of hyper-phosphorylated tau (p-tau). Neuroinflammation and brain iron dyshomeostasis accompany Aβ and p-tau deposits and, together, lead to progressive neuronal death and dementia. The accumulation of Aβ and iron in drusen, the hallmark of AMD, and Aβ and p-tau in retinal ganglion cells (RGC), the main retinal cell type implicated in glaucoma, and accompanying inflammation suggest overlapping pathology. Visual abnormalities are prominent in AD and are believed to develop before cognitive decline. Some are caused by degeneration of the visual cortex, while others are due to RGC loss or AMD-associated retinal degeneration. Here, we review recent information on Aβ, p-tau, chronic inflammation, and iron dyshomeostasis as common pathogenic mechanisms linking the three degenerative conditions, and iron chelation as a common therapeutic option for these disorders. Additionally discussed is the role of prion protein, infamous for prion disorders, in Aβ-mediated toxicity and, paradoxically, in neuroprotection.
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18
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Bellsmith KN, Dunaief JL, Yang P, Pennesi ME, Davis E, Hofkamp H, Lujan BJ. Bull's eye maculopathy associated with hereditary hemochromatosis. Am J Ophthalmol Case Rep 2020; 18:100674. [PMID: 32258826 PMCID: PMC7109569 DOI: 10.1016/j.ajoc.2020.100674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 03/14/2020] [Accepted: 03/17/2020] [Indexed: 10/26/2022] Open
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19
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Shu W, Baumann BH, Song Y, Liu Y, Wu X, Dunaief JL. Iron Accumulates in Retinal Vascular Endothelial Cells But Has Minimal Retinal Penetration After IP Iron Dextran Injection in Mice. Invest Ophthalmol Vis Sci 2020; 60:4378-4387. [PMID: 31634395 PMCID: PMC6798310 DOI: 10.1167/iovs.19-28250] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Purpose Iron supplementation therapy is used for iron-deficiency anemia but has been associated with macular degeneration in a 43-year-old patient. Iron entry into the neurosensory retina (NSR) can be toxic. It is important to determine conditions under which serum iron might cross the blood retinal barrier (BRB) into the NSR. Herein, an established mouse model of systemic iron overload using high-dose intraperitoneal iron dextran (IP FeDex) was studied. In addition, because the NSR expresses the iron regulatory hormone hepcidin, which could limit iron influx into the NSR, we gave retina-specific hepcidin knockout (RS-HepcKO) mice IP FeDex to test this possibility. Methods Wild-type (WT) and RS-HepcKO mice were given IP FeDex. In vivo retina imaging was performed. Blood and tissues were analyzed for iron levels. Quantitative PCR was used to measure levels of mRNAs encoding iron regulatory and photoreceptor-specific genes. Ferritin and albumin were localized in the retina by immunofluorescence. Results IP FeDex in both WT and RS-HepcKO mice induced high levels of iron in the liver, serum, retinal vascular endothelial cells (rVECs), and RPE, but not the NSR. The BRB remained intact. Retinal degeneration did not occur. Conclusions Following injection of high-dose IP FeDex, iron accumulated in the BRB, but not the NSR. Thus, the BRB can shield the NSR from iron delivered in this manner. This ability is not dependent on NSR hepcidin production.
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Affiliation(s)
- Wanting Shu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China.,F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Bailey H Baumann
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Yingrui Liu
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States.,Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, Jilin, China
| | - Xingwei Wu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
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20
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Cathepsin B pH-Dependent Activity Is Involved in Lysosomal Dysregulation in Atrophic Age-Related Macular Degeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:5637075. [PMID: 31885803 PMCID: PMC6925809 DOI: 10.1155/2019/5637075] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/11/2019] [Accepted: 11/05/2019] [Indexed: 12/16/2022]
Abstract
Age-related macular degeneration (AMD) is characterized by retinal pigment epithelial (RPE) cell dysfunction beginning at early stages of the disease. The lack of an appropriate in vitro model is a major limitation in understanding the mechanisms leading to the occurrence of AMD. This study compared human-induced pluripotent stem cell- (hiPSC-) RPE cells derived from atrophic AMD patients (77 y/o ± 7) to hiPSC-RPE cells derived from healthy elderly individuals with no drusen or pigmentary alteration (62.5 y/o ± 17.5). Control and AMD hiPSC-RPE cell lines were characterized by immunofluorescence, flow cytometry, and electronic microscopy. The toxicity level of iron after Fe-NTA treatment was evaluated by an MTT test and by the detection of dichloro-dihydro-fluorescein diacetate. Twelve hiPSC-RPE cell lines (6 AMD and 6 controls) were used for the experiment. Under basal conditions, all hiPSC-RPE cells expressed a phenotypic profile of senescent cells with rounded mitochondria at passage 2. However, the treatment with Fe-NTA induced higher reactive oxygen species production and cell death in hiPSC-RPE AMD cells than in hiPSC-RPE Control cells. Interestingly, functional analysis showed differences in lysosomal activity between the two populations. Indeed, Cathepsin B activity was higher in hiPSC-RPE AMD cells compared to hiPSC-RPE Control cells in basal condition and link to a pH more acidic in this cell population. Moreover, oxidative stress exposure leads to an increase of Cathepsin D immature form levels in both populations, but in a higher proportion in hiPSC-RPE AMD cells. These findings could demonstrate that hiPSC-RPE AMD cells have a typical disease phenotype compared to hiPSC-RPE Control cells.
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Sousa L, Oliveira MM, Pessôa MTC, Barbosa LA. Iron overload: Effects on cellular biochemistry. Clin Chim Acta 2019; 504:180-189. [PMID: 31790701 DOI: 10.1016/j.cca.2019.11.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023]
Abstract
Iron is an essential element for human life. However, it is a pro-oxidant agent capable of reacting with hydrogen peroxide. An iron overload can cause cellular changes, such as damage to the plasma membrane leading to cell death. Effects of iron overload in cellular biochemical processes include modulating membrane enzymes, such as the Na, K-ATPase, impairing the ionic transport and inducing irreversible damage to cellular homeostasis. To avoid such damage, cells have an antioxidant system that acts in an integrated manner to prevent oxidative stress. In addition, the cells contain proteins responsible for iron transport and storage, preventing its reaction with other substances during absorption. Moreover, iron is associated with cellular events coordinated by iron-responsive proteins (IRPs) that regulate several cellular functions, including a process of cell death called ferroptosis. This review will address the biochemical aspects of iron overload at the cellular level and its effects on important cellular structures.
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Affiliation(s)
- Leilismara Sousa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Marina M Oliveira
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Marco Túlio C Pessôa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Leandro A Barbosa
- Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil.
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Baumann BH, Shu W, Song Y, Simpson EM, Lakhal-Littleton S, Dunaief JL. Ferroportin-mediated iron export from vascular endothelial cells in retina and brain. Exp Eye Res 2019; 187:107728. [PMID: 31323276 PMCID: PMC6759385 DOI: 10.1016/j.exer.2019.107728] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/05/2019] [Accepted: 07/15/2019] [Indexed: 12/29/2022]
Abstract
Retinal iron accumulation has been implicated in the pathogenesis of age-related macular degeneration (AMD) and other neurodegenerative diseases. The retina and the brain are protected from the systemic circulation by the blood retinal barrier (BRB) and blood brain barrier (BBB), respectively. Iron levels within the retina and brain need to be tightly regulated to prevent oxidative injury. The method of iron entry through the retina and brain vascular endothelial cells (r&bVECs), an essential component of the BRB and BBB, is not fully understood. However, localization of the cellular iron exporter, ferroportin (Fpn), to the abluminal membrane of these cells, leads to the hypothesis that Fpn may play an important role in the import of iron across the BRB and BBB. To test this hypothesis, a mouse model with deletion of Fpn within the VECs in both the retina and the brain was developed through tail vein injection of AAV9-Ple261(CLDN5)-icre to both experimental Fpnf/f, and control Fpn+/+ mice at P21. Mice were aged to 9 mo and changes in retinal and brain iron distribution were observed. In vivo fundus imaging and quantitative serum iron detection were used for model validation. Eyes and brains were collected for immunofluorescence. Deletion of Fpn from the retinal and brain VECs leads to ferritin-L accumulation, an indicator of elevated iron levels, in the retinal and brain VECs. This occurred despite lower serum iron levels in the experimental mice. This result suggests that Fpn normally transfers iron from retinal and brain VECs into the retina and brain. These results help to better define the method of retina and brain iron import and will increase understanding of neurodegenerative diseases involving iron accumulation.
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Affiliation(s)
- Bailey H Baumann
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, 19104, USA.
| | - Wanting Shu
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, 19104, USA; Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, No. 100 Haining Road, Shanghai, 200080, China.
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, 19104, USA.
| | - Elizabeth M Simpson
- Centre for Molecular Medicine and Therapeutics at the Child & Family Research Institute, University of British Columbia, 950 W 28 Ave, Vancouver, BC, V5Z 4H4, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, V6H 3N1, Canada.
| | - Samira Lakhal-Littleton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
| | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA, 19104, USA.
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Baumann BH, Shu W, Song Y, Sterling J, Kozmik Z, Lakhal-Littleton S, Dunaief JL. Liver-Specific, but Not Retina-Specific, Hepcidin Knockout Causes Retinal Iron Accumulation and Degeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:1814-1830. [PMID: 31287995 PMCID: PMC6723216 DOI: 10.1016/j.ajpath.2019.05.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/23/2019] [Accepted: 05/31/2019] [Indexed: 12/12/2022]
Abstract
The liver secretes hepcidin (Hepc) into the bloodstream to reduce blood iron levels. Hepc accomplishes this by triggering degradation of the only known cellular iron exporter ferroportin in the gut, macrophages, and liver. We previously demonstrated that systemic Hepc knockout (HepcKO) mice, which have high serum iron, develop retinal iron overload and degeneration. However, it was unclear whether this is caused by high blood iron levels or, alternatively, retinal iron influx that would normally be regulated by retina-produced Hepc. To address this question, retinas of liver-specific and retina-specific HepcKO mice were studied. Liver-specific HepcKO mice had elevated blood and retinal pigment epithelium (RPE) iron levels and increased free (labile) iron levels in the retina, despite an intact blood-retinal barrier. This led to RPE hypertrophy associated with lipofuscin-laden lysosome accumulation. Photoreceptors also degenerated focally. In contrast, there was no change in retinal or RPE iron levels or degeneration in the retina-specific HepcKO mice. These data indicate that high blood iron levels can lead to retinal iron accumulation and degeneration. High blood iron levels can occur in patients with hereditary hemochromatosis or result from use of iron supplements or multiple blood transfusions. Our results suggest that high blood iron levels may cause or exacerbate retinal disease.
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Affiliation(s)
- Bailey H Baumann
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, Philadelphia, Pennsylvania
| | - Wanting Shu
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, Philadelphia, Pennsylvania; Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, Philadelphia, Pennsylvania
| | - Jacob Sterling
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, Philadelphia, Pennsylvania
| | - Zbynek Kozmik
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Academy of Sciences of the Czech Republic (ASCR), Prague, Czech Republic
| | - Samira Lakhal-Littleton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, Philadelphia, Pennsylvania.
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SPECKLED HYPOAUTOFLUORESCENCE AS A SIGN OF RESOLVED SUBRETINAL HEMORRHAGE IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION. Retina 2018; 39:1925-1935. [PMID: 30355956 DOI: 10.1097/iae.0000000000002367] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE To describe patterns of hypoautofluorescence in eyes with neovascular age-related macular degeneration occurring after subretinal hemorrhage. METHODS This was a retrospective descriptive analysis of neovascular age-related macular degeneration eyes presenting with subretinal hemorrhage over the last 5 years that underwent serial multimodal imaging. A review of color fundus photographs, fundus autofluorescence, near-infrared reflectance, and optical coherence tomography was performed at baseline and all available follow-up visits to document the course and evolution of subretinal hemorrhage in these eyes. RESULTS Eleven eyes of 10 patients (9 female, 1 male; mean age: 84.1 years, range: 72-99 years) with a mean follow-up of 19.8 months (range: 3-68 months) were included. Color fundus photographs showed subretinal hemorrhage that resolved over a mean of 5.5 months. During and after hemorrhage resolution, all eyes showed hypoautofluorescence, which appeared distinct from that due to retinal pigment epithelium loss. Discrete multifocal punctate hyperpigmented lesions were observed in 90% of eyes and were markedly hypoautofluorescent, producing a speckled pattern on fundus autofluorescence. CONCLUSION Areas of hypoautofluorescence in the absence of retinal pigment epithelium atrophy, often with a speckled pattern, delineate areas of prior subretinal hemorrhage long after its resolution in patients with neovascular age-related macular degeneration. Potential mechanisms for the development of this pattern are proposed.
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Shu W, Dunaief JL. Potential Treatment of Retinal Diseases with Iron Chelators. Pharmaceuticals (Basel) 2018; 11:ph11040112. [PMID: 30360383 PMCID: PMC6316536 DOI: 10.3390/ph11040112] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 10/08/2018] [Accepted: 10/10/2018] [Indexed: 12/30/2022] Open
Abstract
Iron is essential for life, while excess iron can be toxic. Iron generates hydroxyl radical, which is the most reactive free radical, causing oxidative stress. Since iron is absorbed through the diet but not excreted from the body, it accumulates with age in tissues, including the retina, consequently leading to age-related toxicity. This accumulation is further promoted by inflammation. Hereditary diseases such as aceruloplasminemia, Friedreich’s ataxia, pantothenate kinase-associated neurodegeneration, and posterior column ataxia with retinitis pigmentosa involve retinal degeneration associated with iron dysregulation. In addition to hereditary causes, dietary or parenteral iron supplementation has been recently reported to elevate iron levels in the retinal pigment epithelium (RPE) and promote retinal degeneration. Ocular siderosis from intraocular foreign bodies or subretinal hemorrhage can also lead to retinopathy. Evidence from mice and humans suggests that iron toxicity may contribute to age-related macular degeneration pathogenesis. Iron chelators can protect photoreceptors and RPE in various mouse models. The therapeutic potential for iron chelators is under investigation.
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Affiliation(s)
- Wanting Shu
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, Philadelphia, PA 19104, USA.
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China.
| | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, Philadelphia, PA 19104, USA.
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Chaudhary K, Promsote W, Ananth S, Veeranan-Karmegam R, Tawfik A, Arjunan P, Martin P, Smith SB, Thangaraju M, Kisselev O, Ganapathy V, Gnana-Prakasam JP. Iron Overload Accelerates the Progression of Diabetic Retinopathy in Association with Increased Retinal Renin Expression. Sci Rep 2018; 8:3025. [PMID: 29445185 PMCID: PMC5813018 DOI: 10.1038/s41598-018-21276-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/31/2018] [Indexed: 12/31/2022] Open
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness among working-age adults. Increased iron accumulation is associated with several degenerative diseases. However, there are no reports on the status of retinal iron or its implications in the pathogenesis of DR. In the present study, we found that retinas of type-1 and type-2 mouse models of diabetes have increased iron accumulation compared to non-diabetic retinas. We found similar iron accumulation in postmortem retinal samples from human diabetic patients. Further, we induced diabetes in HFE knockout (KO) mice model of genetic iron overload to understand the role of iron in the pathogenesis of DR. We found increased neuronal cell death, vascular alterations and loss of retinal barrier integrity in diabetic HFE KO mice compared to diabetic wildtype mice. Diabetic HFE KO mouse retinas also exhibited increased expression of inflammation and oxidative stress markers. Severity in the pathogenesis of DR in HFE KO mice was accompanied by increase in retinal renin expression mediated by G-protein-coupled succinate receptor GPR91. In light of previous reports implicating retinal renin-angiotensin system in DR pathogenesis, our results reveal a novel relationship between diabetes, iron and renin-angiotensin system, thereby unraveling new therapeutic targets for the treatment of DR.
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Affiliation(s)
- Kapil Chaudhary
- Department of Medicine, Washington University, St. Louis, Missouri, USA
| | | | - Sudha Ananth
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Rajalakshmi Veeranan-Karmegam
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Amany Tawfik
- Dental College of Georgia, Augusta University, Augusta, Georgia, USA
| | | | - Pamela Martin
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Sylvia B Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Muthusamy Thangaraju
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Oleg Kisselev
- Department of Ophthalmology and Department of Biochemistry & Molecular Biology, Saint Louis University, St. Louis, Missouri, USA
| | - Vadivel Ganapathy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Jaya P Gnana-Prakasam
- Department of Ophthalmology and Department of Biochemistry & Molecular Biology, Saint Louis University, St. Louis, Missouri, USA.
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27
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Yusuf IH, Shanks ME, Clouston P, MacLaren RE. A splice-site variant in FLVCR1 produces retinitis pigmentosa without posterior column ataxia. Ophthalmic Genet 2017; 39:263-267. [PMID: 29192808 DOI: 10.1080/13816810.2017.1408848] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
FLVCR1 (feline leukemia virus subgroup c receptor 1) is a transmembrane protein involved in the trafficking of intracellular heme. Homozygous variants in FLVCR1 have been described in association with a clinical syndrome of posterior column ataxia with retinitis pigmentosa (PCARP). Here, we describe a patient with non-syndromic retinitis pigmentosa homozygous for a splice-site variant in FLVCR1 (c.1092 + 5G>A) without evidence of posterior column ataxia or cerebellar degeneration. We suggest an association between intronic splice-site variants in FLVCR1 and the absence of posterior column degeneration and suggest a hypothesis to explain this observation. Should this association be proven, it would provide valuable prognostic information for patients. Retinal degeneration appears to be the sole clinical manifestation of this FLVCR1 variant; gene therapy approaches using an adeno-associated viral vector with sub-retinal delivery may therefore represent a therapeutic approach to halting retinal degeneration in this patient group.
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Affiliation(s)
- Imran H Yusuf
- a Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences , Oxford University , Oxford, UK.,b Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust , Oxford, UK
| | - Morag E Shanks
- c Oxford Medical Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, The Churchill Hospital , Oxford , UK
| | - Penny Clouston
- c Oxford Medical Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, The Churchill Hospital , Oxford , UK
| | - Robert E MacLaren
- a Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences , Oxford University , Oxford, UK.,b Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust , Oxford, UK
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28
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Kumar P, Nag TC, Jha KA, Dey SK, Kathpalia P, Maurya M, Gupta CL, Bhatia J, Roy TS, Wadhwa S. Experimental oral iron administration: Histological investigations and expressions of iron handling proteins in rat retina with aging. Toxicology 2017; 392:22-31. [PMID: 28993186 DOI: 10.1016/j.tox.2017.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/05/2017] [Accepted: 10/06/2017] [Indexed: 01/19/2023]
Abstract
Iron is implicated in age-related macular degeneration (AMD). The aim of this study was to see if long-term, experimental iron administration with aging modifies retinal and choroidal structures and expressions of iron handling proteins, to understand some aspects of iron homeostasis. Male Wistar rats were fed with ferrous sulphate heptahydrate (500mg/kg body weight/week, oral; elemental iron availability: 20%) from 2 months of age onward until they were 19.5 month-old. At 8, 14 and 20 months of age, they were sacrificed and serum and retinal iron levels were detected by HPLC. Oxidative stress was analyzed by TBARS method. The retinas were examined for cell death (TUNEL), histology (electron microscopy) and the expressions of transferrin, transferrin receptor-1 [TFR-1], H- and L-ferritin. In control animals, at any age, there was no difference in the serum and retinal iron levels, but the latter increased significantly in 14- and 20 month-old iron-fed rats, indicating that retinal iron accumulation proceeds with progression of aging (>14 months). The serum and retinal TBARS levels increased significantly with progression of aging in experimental but not in control rats. There was significant damage to choriocapillaris, accumulation of phagosomes in retinal pigment epithelium and increased incidence of TUNEL+ cells in outer nuclear layer and vacuolation in inner nuclear layer (INL) of 20 month-aged experimental rats, compared to those in age-matched controls. Vacuolations in INL could indicate a long-term effect of iron accumulation in the inner retina. These events paralleled the increased expression of ferritins and transferrin and a decrease in the expression of TFR-1 in iron-fed rats with aging, thereby maintaining iron homeostasis in the retina. As some of these changes mimic with those happening in eyes with AMD, this model can be utilized to understand iron-induced pathophysiological changes in AMD.
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Affiliation(s)
- Pankaj Kumar
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Tapas Chandra Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Kumar Abhiram Jha
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Sanjay Kumar Dey
- Department of Biochemistry, Delhi University South Campus, New Delhi 110021, India.
| | - Poorti Kathpalia
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Meenakshi Maurya
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Chandan Lal Gupta
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Jagriti Bhatia
- Department of Pharmacology, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Tara Sankar Roy
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Shashi Wadhwa
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
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