1
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Amer R, Koriat A. Aqueous humor perturbations in chronic smokers: a proteomic study. Sci Rep 2024; 14:11279. [PMID: 38760463 PMCID: PMC11101467 DOI: 10.1038/s41598-024-62039-6] [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: 08/21/2023] [Accepted: 05/13/2024] [Indexed: 05/19/2024] Open
Abstract
The detrimental effects of smoking are multisystemic and its effects on the eye health are significant. Smoking is a strong risk factor for age-related nuclear cataract, age-related macular degeneration, glaucoma, delayed corneal epithelial healing and increased risk of cystoid macular edema in patients with intermediate uveitis among others. We aimed to characterize the aqueous humor (AH) proteome in chronic smokers to gain insight into its perturbations and to identify potential biomarkers for smoking-associated ocular pathologies. Compared to the control group, chronic smokers displayed 67 (37 upregulated, 30 downregulated) differentially expressed proteins (DEPs). Analysis of DEPs from the biological point of view revealed that they were proteins involved in complement activation, lymphocyte mediated immunity, innate immune response, cellular oxidant detoxification, bicarbonate transport and platelet degranulation. From the molecular function point of view, DEPs were involved in oxygen binding, oxygen carrier activity, hemoglobin binding, peptidase/endopeptidase/cysteine-type endopeptidase inhibitory activity. Several of the upregulated proteins were acute phase reactant proteins such as clusterin, alpha-2-HS-glycoprotein, fibrinogen, alpha-1-antitrypsin, C4b-binding protein and serum amyloid A-2. Further research should confirm if these proteins might serve as biomarkers or therapeutic target for smoking-associated ocular diseases.
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Affiliation(s)
- Radgonde Amer
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel.
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Adi Koriat
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
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2
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Becker S, L'Ecuyer Z, Jones BW, Zouache MA, McDonnell FS, Vinberg F. Modeling complex age-related eye disease. Prog Retin Eye Res 2024; 100:101247. [PMID: 38365085 PMCID: PMC11268458 DOI: 10.1016/j.preteyeres.2024.101247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Modeling complex eye diseases like age-related macular degeneration (AMD) and glaucoma poses significant challenges, since these conditions depend highly on age-related changes that occur over several decades, with many contributing factors remaining unknown. Although both diseases exhibit a relatively high heritability of >50%, a large proportion of individuals carrying AMD- or glaucoma-associated genetic risk variants will never develop these diseases. Furthermore, several environmental and lifestyle factors contribute to and modulate the pathogenesis and progression of AMD and glaucoma. Several strategies replicate the impact of genetic risk variants, pathobiological pathways and environmental and lifestyle factors in AMD and glaucoma in mice and other species. In this review we will primarily discuss the most commonly available mouse models, which have and will likely continue to improve our understanding of the pathobiology of age-related eye diseases. Uncertainties persist whether small animal models can truly recapitulate disease progression and vision loss in patients, raising doubts regarding their usefulness when testing novel gene or drug therapies. We will elaborate on concerns that relate to shorter lifespan, body size and allometries, lack of macula and a true lamina cribrosa, as well as absence and sequence disparities of certain genes and differences in their chromosomal location in mice. Since biological, rather than chronological, age likely predisposes an organism for both glaucoma and AMD, more rapidly aging organisms like small rodents may open up possibilities that will make research of these diseases more timely and financially feasible. On the other hand, due to the above-mentioned anatomical and physiological features, as well as pharmacokinetic and -dynamic differences small animal models are not ideal to study the natural progression of vision loss or the efficacy and safety of novel therapies. In this context, we will also discuss the advantages and pitfalls of alternative models that include larger species, such as non-human primates and rabbits, patient-derived retinal organoids, and human organ donor eyes.
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Affiliation(s)
- Silke Becker
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Zia L'Ecuyer
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Bryan W Jones
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Moussa A Zouache
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Fiona S McDonnell
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Frans Vinberg
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
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3
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Kim S, Chae JB, Kim D, Park CW, Sim Y, Lee H, Park G, Lee J, Hong S, Jana B, Kim C, Chung H, Ryu JH. Supramolecular Senolytics via Intracellular Oligomerization of Peptides in Response to Elevated Reactive Oxygen Species Levels in Aging Cells. J Am Chem Soc 2023; 145:21991-22008. [PMID: 37664981 DOI: 10.1021/jacs.3c06898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Senolytics, which eliminate senescent cells from tissues, represent an emerging therapeutic strategy for various age-related diseases. Most senolytics target antiapoptotic proteins, which are overexpressed in senescent cells, limiting specificity and inducing severe side effects. To overcome these limitations, we constructed self-assembling senolytics targeting senescent cells with an intracellular oligomerization system. Intracellular aryl-dithiol-containing peptide oligomerization occurred only inside the mitochondria of senescent cells due to selective localization of the peptides by RGD-mediated cellular uptake into integrin αvβ3-overexpressed senescent cells and elevated levels of reactive oxygen species, which can be used as a chemical fuel for disulfide formation. This oligomerization results in an artificial protein-like nanoassembly with a stable α-helix secondary structure, which can disrupt the mitochondrial membrane via multivalent interactions because the mitochondrial membrane of senescent cells has weaker integrity than that of normal cells. These three specificities (integrin αvβ3, high ROS, and weak mitochondrial membrane integrity) of senescent cells work in combination; therefore, this intramitochondrial oligomerization system can selectively induce apoptosis of senescent cells without side effects on normal cells. Significant reductions in key senescence markers and amelioration of retinal degeneration were observed after elimination of the senescent retinal pigment epithelium by this peptide senolytic in an age-related macular degeneration mouse model and in aged mice, and this effect was accompanied by improved visual function. This system provides a strategy for the treatment of age-related diseases using supramolecular senolytics.
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Affiliation(s)
- Sangpil Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jae-Byoung Chae
- Department of Ophthalmology, Konkuk University School of Medicine, Seoul 05029, Republic of Korea
| | - Dohyun Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Chul-Woo Park
- Department of Ophthalmology, Konkuk University School of Medicine, Seoul 05029, Republic of Korea
| | - Youjung Sim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Hyungwoo Lee
- Department of Ophthalmology, Konkuk University School of Medicine, Seoul 05029, Republic of Korea
| | - Gaeun Park
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jaeeun Lee
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Seongho Hong
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Batakrishna Jana
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Chaekyu Kim
- Fusion Biotechnology, Ulsan 44919, Republic of Korea
| | - Hyewon Chung
- Department of Ophthalmology, Konkuk University School of Medicine, Seoul 05029, Republic of Korea
| | - Ja-Hyoung Ryu
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
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4
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Hammadi S, Tzoumas N, Ferrara M, Meschede IP, Lo K, Harris C, Lako M, Steel DH. Bruch's Membrane: A Key Consideration with Complement-Based Therapies for Age-Related Macular Degeneration. J Clin Med 2023; 12:2870. [PMID: 37109207 PMCID: PMC10145879 DOI: 10.3390/jcm12082870] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/29/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
The complement system is crucial for immune surveillance, providing the body's first line of defence against pathogens. However, an imbalance in its regulators can lead to inappropriate overactivation, resulting in diseases such as age-related macular degeneration (AMD), a leading cause of irreversible blindness globally affecting around 200 million people. Complement activation in AMD is believed to begin in the choriocapillaris, but it also plays a critical role in the subretinal and retinal pigment epithelium (RPE) spaces. Bruch's membrane (BrM) acts as a barrier between the retina/RPE and choroid, hindering complement protein diffusion. This impediment increases with age and AMD, leading to compartmentalisation of complement activation. In this review, we comprehensively examine the structure and function of BrM, including its age-related changes visible through in vivo imaging, and the consequences of complement dysfunction on AMD pathogenesis. We also explore the potential and limitations of various delivery routes (systemic, intravitreal, subretinal, and suprachoroidal) for safe and effective delivery of conventional and gene therapy-based complement inhibitors to treat AMD. Further research is needed to understand the diffusion of complement proteins across BrM and optimise therapeutic delivery to the retina.
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Affiliation(s)
- Sarah Hammadi
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Nikolaos Tzoumas
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
| | | | - Ingrid Porpino Meschede
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Katharina Lo
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Claire Harris
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
- Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Majlinda Lako
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - David H. Steel
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
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5
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Braun JEA. Extracellular chaperone networks and the export of J-domain proteins. J Biol Chem 2023; 299:102840. [PMID: 36581212 PMCID: PMC9867986 DOI: 10.1016/j.jbc.2022.102840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/18/2022] [Accepted: 12/20/2022] [Indexed: 12/27/2022] Open
Abstract
An extracellular network of molecular chaperones protects a diverse array of proteins that reside in or pass through extracellular spaces. Proteins in the extracellular milieu face numerous challenges that can lead to protein misfolding and aggregation. As a checkpoint for proteins that move between cells, extracellular chaperone networks are of growing clinical relevance. J-domain proteins (JDPs) are ubiquitous molecular chaperones that are known for their essential roles in a wide array of fundamental cellular processes through their regulation of heat shock protein 70s. As the largest molecular chaperone family, JDPs have long been recognized for their diverse functions within cells. Some JDPs are elegantly selective for their "client proteins," some do not discriminate among substrates and others act cooperatively on the same target. The realization that JDPs are exported through both classical and unconventional secretory pathways has fueled investigation into the roles that JDPs play in protein quality control and intercellular communication. The proposed functions of exported JDPs are diverse. Studies suggest that export of DnaJB11 enhances extracellular proteostasis, that intercellular movement of DnaJB1 or DnaJB6 enhances the proteostasis capacity in recipient cells, whereas the import of DnaJB8 increases resistance to chemotherapy in recipient cancer cells. In addition, the export of DnaJC5 and concurrent DnaJC5-dependent ejection of dysfunctional and aggregation-prone proteins are implicated in the prevention of neurodegeneration. This review provides a brief overview of the current understanding of the extracellular chaperone networks and outlines the first wave of studies describing the cellular export of JDPs.
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Affiliation(s)
- Janice E A Braun
- Department of Biochemistry and Molecular Biology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
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6
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Kurzawa‐Akanbi M, Whitfield P, Burté F, Bertelli PM, Pathak V, Doherty M, Hilgen B, Gliaudelytė L, Platt M, Queen R, Coxhead J, Porter A, Öberg M, Fabrikova D, Davey T, Beh CS, Georgiou M, Collin J, Boczonadi V, Härtlova A, Taggart M, Al‐Aama J, Korolchuk VI, Morris CM, Guduric‐Fuchs J, Steel DH, Medina RJ, Armstrong L, Lako M. Retinal pigment epithelium extracellular vesicles are potent inducers of age-related macular degeneration disease phenotype in the outer retina. J Extracell Vesicles 2022; 11:e12295. [PMID: 36544284 PMCID: PMC9772497 DOI: 10.1002/jev2.12295] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 11/18/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness. Vision loss is caused by the retinal pigment epithelium (RPE) and photoreceptors atrophy and/or retinal and choroidal angiogenesis. Here we use AMD patient-specific RPE cells with the Complement Factor H Y402H high-risk polymorphism to perform a comprehensive analysis of extracellular vesicles (EVs), their cargo and role in disease pathology. We show that AMD RPE is characterised by enhanced polarised EV secretion. Multi-omics analyses demonstrate that AMD RPE EVs carry RNA, proteins and lipids, which mediate key AMD features including oxidative stress, cytoskeletal dysfunction, angiogenesis and drusen accumulation. Moreover, AMD RPE EVs induce amyloid fibril formation, revealing their role in drusen formation. We demonstrate that exposure of control RPE to AMD RPE apical EVs leads to the acquisition of AMD features such as stress vacuoles, cytoskeletal destabilization and abnormalities in the morphology of the nucleus. Retinal organoid treatment with apical AMD RPE EVs leads to disrupted neuroepithelium and the appearance of cytoprotective alpha B crystallin immunopositive cells, with some co-expressing retinal progenitor cell markers Pax6/Vsx2, suggesting injury-induced regenerative pathways activation. These findings indicate that AMD RPE EVs are potent inducers of AMD phenotype in the neighbouring RPE and retinal cells.
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Affiliation(s)
- Marzena Kurzawa‐Akanbi
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Phillip Whitfield
- Glasgow Polyomics and Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Florence Burté
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Pietro Maria Bertelli
- The Welcome‐Wolfson Institute for Experimental MedicineQueen's University BelfastBelfastUK
| | - Varun Pathak
- The Welcome‐Wolfson Institute for Experimental MedicineQueen's University BelfastBelfastUK
| | - Mary Doherty
- Lipidomics Research FacilityUniversity of the Highlands and IslandsInvernessUK
| | - Birthe Hilgen
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Lina Gliaudelytė
- Translational and Clinical Research InstituteNewcastle UniversityNewcastle upon TyneUK
| | | | - Rachel Queen
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Jonathan Coxhead
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Andrew Porter
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Maria Öberg
- Institute of Biomedicine, Department of Microbiology and Immunology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Wallenberg Center for Molecular and Translational MedicineUniversity of GothenburgGothenburgSweden
| | - Daniela Fabrikova
- Institute of Biomedicine, Department of Microbiology and Immunology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Wallenberg Center for Molecular and Translational MedicineUniversity of GothenburgGothenburgSweden
| | - Tracey Davey
- Electron Microscopy Research ServicesNewcastle UniversityNewcastle upon TyneUK
| | - Chia Shyan Beh
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Maria Georgiou
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Joseph Collin
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Veronika Boczonadi
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Anetta Härtlova
- Institute of Biomedicine, Department of Microbiology and Immunology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Wallenberg Center for Molecular and Translational MedicineUniversity of GothenburgGothenburgSweden
- The Institute of Medical Microbiology and HygieneUniversity Medical Center Freiburg (Universitätklinikum Freiburg)FreiburgGermany
| | - Michael Taggart
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Jumana Al‐Aama
- Faculty of MedicineKing Abdulaziz UniversityJeddahSaudi Arabia
| | - Viktor I Korolchuk
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Christopher M Morris
- Translational and Clinical Research InstituteNewcastle UniversityNewcastle upon TyneUK
| | - Jasenka Guduric‐Fuchs
- The Welcome‐Wolfson Institute for Experimental MedicineQueen's University BelfastBelfastUK
| | - David H Steel
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Reinhold J Medina
- The Welcome‐Wolfson Institute for Experimental MedicineQueen's University BelfastBelfastUK
| | - Lyle Armstrong
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Majlinda Lako
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
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7
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Keeling E, Lynn SA, Koh YM, Scott JA, Kendall A, Gatherer M, Page A, Cagampang FR, Lotery AJ, Ratnayaka JA. A High Fat "Western-style" Diet Induces AMD-Like Features in Wildtype Mice. Mol Nutr Food Res 2022; 66:e2100823. [PMID: 35306732 PMCID: PMC9287010 DOI: 10.1002/mnfr.202100823] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 03/01/2022] [Indexed: 12/20/2022]
Abstract
Scope The intake of a “Western‐style” diet rich in fats is linked with developing retinopathies including age‐related macular degeneration (AMD). Wildtype mice are given a high fat diet (HFD) to determine how unhealthy foods can bring about retinal degeneration. Methods and results Following weaning, female C57BL/6 mice are maintained on standard chow (7% kcal fat, n = 29) or a HFD (45% kcal fat, n = 27) for 12 months. Animals were sacrificed following electroretinography (ERG) and their eyes analyzed by histology, confocal immunofluorescence, and transmission electron microscopy. HFD mice become obese, but showed normal retinal function compared to chow‐fed controls. However, diminished β3tubulin labeling of retinal cross‐sections indicated fewer/damaged neuronal processes in the inner plexiform layer. AMD‐linked proteins clusterin and TIMP3 accumulated in the retinal pigment epithelium (RPE) and Bruch's membrane (BrM). Neutral lipids also deposited in the outer retinae of HFD mice. Ultrastructural analysis revealed disorganized photoreceptor outer segments, collapsed/misaligned RPE microvilli, vacuoles, convoluted basolateral RPE infolds and BrM changes. Basal laminar‐like deposits were also present alongside abnormal choroidal endothelial cells. Conclusions We show that prolonged exposure to an unhealthy “Western‐style” diet alone can recapitulate early‐intermediate AMD‐like features in wildtype mice, highlighting the importance of diet and nutrition in the etiology of sight‐loss.
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Affiliation(s)
- Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, UK
| | - Savannah A Lynn
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, UK
| | - Yen Min Koh
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, UK
| | - Jenny A Scott
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, UK
| | - Aaron Kendall
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, UK
| | - Maureen Gatherer
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, UK
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, Southampton, SO16 6YD, UK
| | - Felino R Cagampang
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, UK.,Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, UK
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8
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Santos FM, Mesquita J, Castro-de-Sousa JP, Ciordia S, Paradela A, Tomaz CT. Vitreous Humor Proteome: Targeting Oxidative Stress, Inflammation, and Neurodegeneration in Vitreoretinal Diseases. Antioxidants (Basel) 2022; 11:505. [PMID: 35326156 PMCID: PMC8944522 DOI: 10.3390/antiox11030505] [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: 02/13/2022] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 12/12/2022] Open
Abstract
Oxidative stress is defined as an unbalance between pro-oxidants and antioxidants, as evidenced by an increase in reactive oxygen and reactive nitrogen species production over time. It is important in the pathophysiology of retinal disorders such as diabetic retinopathy, age-related macular degeneration, retinal detachment, and proliferative vitreoretinopathy, which are the focus of this article. Although the human organism's defense mechanisms correct autoxidation caused by endogenous or exogenous factors, this may be insufficient, causing an imbalance in favor of excessive ROS production or a weakening of the endogenous antioxidant system, resulting in molecular and cellular damage. Furthermore, modern lifestyles and environmental factors contribute to increased chemical exposure and stress induction, resulting in oxidative stress. In this review, we discuss the current information about oxidative stress and the vitreous proteome with a special focus on vitreoretinal diseases. Additionally, we explore therapies using antioxidants in an attempt to rescue the body from oxidation, restore balance, and maximize healthy body function, as well as new investigational therapies that have shown significant therapeutic potential in preclinical studies and clinical trial outcomes, along with their goals and strategic approaches to combat oxidative stress.
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Affiliation(s)
- Fátima Milhano Santos
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001 Covilhã, Portugal; or (J.P.C.-d.-S.)
- Unidad de Proteomica, Centro Nacional de Biotecnología, CSIC, Campus de Cantoblanco, 28049 Madrid, Spain; (S.C.); (A.P.)
- C4-UBI, Cloud Computing Competence Centre, University of Beira Interior, 6200-501 Covilhã, Portugal
| | - Joana Mesquita
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001 Covilhã, Portugal; or (J.P.C.-d.-S.)
| | - João Paulo Castro-de-Sousa
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001 Covilhã, Portugal; or (J.P.C.-d.-S.)
- Department of Ophthalmology, Centro Hospitalar de Leiria, 2410-197 Leiria, Portugal
| | - Sergio Ciordia
- Unidad de Proteomica, Centro Nacional de Biotecnología, CSIC, Campus de Cantoblanco, 28049 Madrid, Spain; (S.C.); (A.P.)
| | - Alberto Paradela
- Unidad de Proteomica, Centro Nacional de Biotecnología, CSIC, Campus de Cantoblanco, 28049 Madrid, Spain; (S.C.); (A.P.)
| | - Cândida Teixeira Tomaz
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6201-001 Covilhã, Portugal; or (J.P.C.-d.-S.)
- C4-UBI, Cloud Computing Competence Centre, University of Beira Interior, 6200-501 Covilhã, Portugal
- Chemistry Department, Faculty of Sciences, University of Beira Interior, 6201-001 Covilhã, Portugal
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9
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Zhang Y, Jiao Y, Li X, Gao S, Zhou N, Duan J, Zhang M. Pyroptosis: A New Insight Into Eye Disease Therapy. Front Pharmacol 2021; 12:797110. [PMID: 34925047 PMCID: PMC8678479 DOI: 10.3389/fphar.2021.797110] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/15/2021] [Indexed: 02/05/2023] Open
Abstract
Pyroptosis is a lytic form of programmed cell death mediated by gasdermins (GSDMs) with pore-forming activity in response to certain exogenous and endogenous stimuli. The inflammasomes are intracellular multiprotein complexes consisting of pattern recognition receptors, an adaptor protein ASC (apoptosis speck-like protein), and caspase-1 and cause autocatalytic activation of caspase-1, which cleaves gasdermin D (GSDMD), inducing pyroptosis accompanied by cytokine release. In recent years, the pathogenic roles of inflammasomes and pyroptosis in multiple eye diseases, including keratitis, dry eyes, cataracts, glaucoma, uveitis, age-related macular degeneration, and diabetic retinopathy, have been continuously confirmed. Inhibiting inflammasome activation and abnormal pyroptosis in eyes generally attenuates inflammation and benefits prognosis. Therefore, insight into the pathogenesis underlying pyroptosis and inflammasome development in various types of eye diseases may provide new therapeutic strategies for ocular disorders. Inhibitors of pyroptosis, such as NLRP3, caspase-1, and GSDMD inhibitors, have been proven to be effective in many eye diseases. The purpose of this article is to illuminate the mechanism underlying inflammasome activation and pyroptosis and emphasize its crucial role in various ocular disorders. In addition, we review the application of pyroptosis modulators in eye diseases.
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Affiliation(s)
- Yun Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China.,Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Yan Jiao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Xun Li
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China.,Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Sheng Gao
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China.,Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Nenghua Zhou
- Key Laboratory of Drug Targeting and Drug Delivery System of Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, China
| | - Jianan Duan
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China.,Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Meixia Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China.,Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
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Flores‐Bellver M, Mighty J, Aparicio‐Domingo S, Li KV, Shi C, Zhou J, Cobb H, McGrath P, Michelis G, Lenhart P, Bilousova G, Heissel S, Rudy MJ, Coughlan C, Goodspeed AE, Becerra SP, Redenti S, Canto‐Soler MV. Extracellular vesicles released by human retinal pigment epithelium mediate increased polarised secretion of drusen proteins in response to AMD stressors. J Extracell Vesicles 2021; 10:e12165. [PMID: 34750957 PMCID: PMC8575963 DOI: 10.1002/jev2.12165] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 10/06/2021] [Accepted: 10/25/2021] [Indexed: 12/22/2022] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. Drusen are key contributors to the etiology of AMD and the ability to modulate drusen biogenesis could lead to therapeutic strategies to slow or halt AMD progression. The mechanisms underlying drusen biogenesis, however, remain mostly unknown. Here we demonstrate that under homeostatic conditions extracellular vesicles (EVs) secreted by retinal pigment epithelium (RPE) cells are enriched in proteins associated with mechanisms involved in AMD pathophysiology, including oxidative stress, immune response, inflammation, complement system and drusen composition. Furthermore, we provide first evidence that drusen-associated proteins are released as cargo of extracellular vesicles secreted by RPE cells in a polarised apical:basal mode. Notably, drusen-associated proteins exhibited distinctive directional secretion modes in homeostatic conditions and, differential modulation of this directional secretion in response to AMD stressors. These observations underpin the existence of a finely-tuned mechanism regulating directional apical:basal sorting and secretion of drusen-associated proteins via EVs, and its modulation in response to mechanisms involved in AMD pathophysiology. Collectively, our results strongly support an active role of RPE-derived EVs as a key source of drusen proteins and important contributors to drusen development and growth.
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Affiliation(s)
- Miguel Flores‐Bellver
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Jason Mighty
- Lehman CollegeBronxNew YorkUSA
- Biology Doctoral ProgramThe Graduate School and University CenterCity University of New YorkNew YorkNew YorkUSA
| | - Silvia Aparicio‐Domingo
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Kang V. Li
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Cui Shi
- Lehman CollegeBronxNew YorkUSA
- Biology Doctoral ProgramThe Graduate School and University CenterCity University of New YorkNew YorkNew YorkUSA
| | | | - Hannah Cobb
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Patrick McGrath
- Department of DermatologyUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - German Michelis
- Section of Protein Structure and FunctionNEINIHBethesdaMarylandUSA
| | - Patricia Lenhart
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Ganna Bilousova
- Department of DermatologyUniversity of Colorado School of MedicineAuroraColoradoUSA
- Charles C. Gates Center for Regenerative MedicineUniversity of Colorado School of MedicineAuroraColoradoUSA
- Linda Crnic Institute for Down SyndromeUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Søren Heissel
- Proteomics Resource CenterThe Rockefeller UniversityNew YorkNew YorkUSA
| | - Michael J. Rudy
- Department of NeurologyUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Christina Coughlan
- University of Colorado Alzheimer's and Cognition CenterDepartment of NeurologyLinda Crnic Institute for Down SyndromeUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Andrew E. Goodspeed
- Department of PharmacologyUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
- University of Colorado Cancer CenterUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | | | - Stephen Redenti
- Lehman CollegeBronxNew YorkUSA
- Biology Doctoral ProgramThe Graduate School and University CenterCity University of New YorkNew YorkNew YorkUSA
- Biochemistry Doctoral ProgramThe Graduate SchoolCity University of New YorkNew YorkNew YorkUSA
| | - M. Valeria Canto‐Soler
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
- Charles C. Gates Center for Regenerative MedicineUniversity of Colorado School of MedicineAuroraColoradoUSA
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Paraoan L, Sharif U, Carlsson E, Supharattanasitthi W, Mahmud NM, Kamalden TA, Hiscott P, Jackson M, Grierson I. Secretory proteostasis of the retinal pigmented epithelium: Impairment links to age-related macular degeneration. Prog Retin Eye Res 2020; 79:100859. [PMID: 32278708 DOI: 10.1016/j.preteyeres.2020.100859] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 03/24/2020] [Accepted: 03/26/2020] [Indexed: 12/19/2022]
Abstract
Secretory proteostasis integrates protein synthesis, processing, folding and trafficking pathways that are essential for efficient cellular secretion. For the retinal pigment epithelium (RPE), secretory proteostasis is of vital importance for the maintenance of the structural and functional integrity of apical (photoreceptors) and basal (Bruch's membrane/choroidal blood supply) sides of the environment it resides in. This integrity is achieved through functions governed by RPE secreted proteins, which include extracellular matrix modelling/remodelling, angiogenesis and immune response modulation. Impaired RPE secretory proteostasis affects not only the extracellular environment, but leads to intracellular protein aggregation and ER-stress with subsequent cell death. Ample recent evidence implicates dysregulated proteostasis as a key factor in the development of age-related macular degeneration (AMD), the leading cause of blindness in the developed world, and research aiming to characterise the roles of various proteins implicated in AMD-associated dysregulated proteostasis unveiled unexpected facets of the mechanisms involved in degenerative pathogenesis. This review analyses cellular processes unveiled by the study of the top 200 transcripts most abundantly expressed by the RPE/choroid in the light of the specialised secretory nature of the RPE. Functional roles of these proteins and the mechanisms of their impaired secretion, due to age and genetic-related causes, are analysed in relation to AMD development. Understanding the importance of RPE secretory proteostasis in relation to maintaining retinal health and how it becomes impaired in disease is of paramount importance for the development and assessment of future therapeutic advancements involving gene and cell therapies.
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Affiliation(s)
- Luminita Paraoan
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom.
| | - Umar Sharif
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Emil Carlsson
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Wasu Supharattanasitthi
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom; Department of Physiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Nur Musfirah Mahmud
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Tengku Ain Kamalden
- Eye Research Centre, Department of Ophthalmology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Paul Hiscott
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Malcolm Jackson
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Ian Grierson
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
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On the origin of proteins in human drusen: The meet, greet and stick hypothesis. Prog Retin Eye Res 2018; 70:55-84. [PMID: 30572124 DOI: 10.1016/j.preteyeres.2018.12.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 12/12/2022]
Abstract
Retinal drusen formation is not only a clinical hallmark for the development of age-related macular degeneration (AMD) but also for other disorders, such as Alzheimer's disease and renal diseases. The initiation and growth of drusen is poorly understood. Attention has focused on lipids and minerals, but relatively little is known about the origin of drusen-associated proteins and how they are retained in the space between the basal lamina of the retinal pigment epithelium and the inner collagenous layer space (sub-RPE-BL space). While some authors suggested that drusen proteins are mainly derived from cellular debris from processed photoreceptor outer segments and the RPE, others suggest a choroidal cell or blood origin. Here, we reviewed and supplemented the existing literature on the molecular composition of the retina/choroid complex, to gain a more complete understanding of the sources of proteins in drusen. These "drusenomics" studies showed that a considerable proportion of currently identified drusen proteins is uniquely originating from the blood. A smaller, but still large fraction of drusen proteins comes from both blood and/or RPE. Only a small proportion of drusen proteins is uniquely derived from the photoreceptors or choroid. We next evaluated how drusen components may "meet, greet and stick" to each other and/or to structures like hydroxyapatite spherules to form macroscopic deposits in the sub-RPE-BL space. Finally, we discuss implications of our findings with respect to the previously proposed homology between drusenogenesis in AMD and plaque formation in atherosclerosis.
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Kheitan S, Minuchehr Z, Soheili ZS. Exploring the cross talk between ER stress and inflammation in age-related macular degeneration. PLoS One 2017; 12:e0181667. [PMID: 28742151 PMCID: PMC5524348 DOI: 10.1371/journal.pone.0181667] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/05/2017] [Indexed: 12/15/2022] Open
Abstract
Increasing evidence demonstrates that inflammation and endoplasmic reticulum (ER) stress is implicated in the development and progression of age-related macular degeneration (AMD), a multifactorial neurodegenerative disease. However the cross talk between these cellular mechanisms has not been clearly and fully understood. The present study investigates a possible intersection between ER stress and inflammation in AMD. In this study, we recruited two collections of involved protein markers to retrieve their interaction information from IMEx-curated databases, which are the most well- known protein-protein interaction collections, allowing us to design an intersection network for AMD that is unprecedented. In order to find expression activated subnetworks, we utilized AMD expression profiles in our network. In addition, we studied topological characteristics of the most expressed active subnetworks to identify the hubs. With regard to topological quantifications and expressional activity, we reported a list of the most pivotal hubs which are potentially applicable as probable therapeutic targets. Furthermore, we introduced MAPK signaling pathway as a significantly involved pathway in the association between ER stress and inflammation, leading to promising new directions in discovering AMD formation mechanisms and possible treatments.
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Affiliation(s)
- Samira Kheitan
- Systems Biotechnology Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Zarrin Minuchehr
- Systems Biotechnology Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
- * E-mail:
| | - Zahra-Soheila Soheili
- Molecular Medicine Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
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Shin JY, Son A, Kim H, Kim Y, Yu HG. Carboxymethyl-lysine-modified plasma proteins in age-related macular degeneration. BIOTECHNOL BIOPROC E 2017. [DOI: 10.1007/s12257-016-0504-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Kauppinen A, Paterno JJ, Blasiak J, Salminen A, Kaarniranta K. Inflammation and its role in age-related macular degeneration. Cell Mol Life Sci 2016; 73:1765-86. [PMID: 26852158 PMCID: PMC4819943 DOI: 10.1007/s00018-016-2147-8] [Citation(s) in RCA: 453] [Impact Index Per Article: 56.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 01/21/2016] [Accepted: 01/25/2016] [Indexed: 01/05/2023]
Abstract
Inflammation is a cellular response to factors that challenge the homeostasis of cells and tissues. Cell-associated and soluble pattern-recognition receptors, e.g. Toll-like receptors, inflammasome receptors, and complement components initiate complex cellular cascades by recognizing or sensing different pathogen and damage-associated molecular patterns, respectively. Cytokines and chemokines represent alarm messages for leukocytes and once activated, these cells travel long distances to targeted inflamed tissues. Although it is a crucial survival mechanism, prolonged inflammation is detrimental and participates in numerous chronic age-related diseases. This article will review the onset of inflammation and link its functions to the pathogenesis of age-related macular degeneration (AMD), which is the leading cause of severe vision loss in aged individuals in the developed countries. In this progressive disease, degeneration of the retinal pigment epithelium (RPE) results in the death of photoreceptors, leading to a loss of central vision. The RPE is prone to oxidative stress, a factor that together with deteriorating functionality, e.g. decreased intracellular recycling and degradation due to attenuated heterophagy/autophagy, induces inflammation. In the early phases, accumulation of intracellular lipofuscin in the RPE and extracellular drusen between RPE cells and Bruch's membrane can be clinically detected. Subsequently, in dry (atrophic) AMD there is geographic atrophy with discrete areas of RPE loss whereas in the wet (exudative) form there is neovascularization penetrating from the choroid to retinal layers. Elevations in levels of local and systemic biomarkers indicate that chronic inflammation is involved in the pathogenesis of both disease forms.
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Affiliation(s)
- Anu Kauppinen
- Faculty of Health Sciences, School of Pharmacy, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
- Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland.
| | - Jussi J Paterno
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Janusz Blasiak
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
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Abstract
The formation of extracellular deposits known as drusen below the macular region of the retina correlates with increased risk of severe visual loss from age-related macular degeneration (AMD). Inflammation and complement dysregulation contribute to AMD progression; however, disease mechanisms remain incompletely defined. Multiple genetic and environmental factors influence AMD pathology, and although immune system processes play a central role, multiple molecular mechanisms appear to be involved. Drusen proteomics, including the analyses of constituent proteins, oxidative protein modifications, and pattern recognition receptors, provide a foundation for deciphering mechanisms of drusen biogenesis and AMD pathology.
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Affiliation(s)
- John W Crabb
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio 44195
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Bowes Rickman C, Farsiu S, Toth CA, Klingeborn M. Dry age-related macular degeneration: mechanisms, therapeutic targets, and imaging. Invest Ophthalmol Vis Sci 2013; 54:ORSF68-80. [PMID: 24335072 DOI: 10.1167/iovs.13-12757] [Citation(s) in RCA: 190] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration is the leading cause of irreversible visual dysfunction in individuals over 65 in Western Society. Patients with AMD are classified as having early stage disease (early AMD), in which visual function is affected, or late AMD (generally characterized as either "wet" neovascular AMD, "dry" atrophic AMD or both), in which central vision is severely compromised or lost. Until recently, there have been no therapies available to treat the disorder(s). Now, the most common wet form of late-stage AMD, choroidal neovascularization, generally responds to treatment with anti-vascular endothelial growth factor therapies. Nevertheless, there are no current therapies to restore lost vision in eyes with advanced atrophic AMD. Oral supplementation with the Age-Related Eye Disease Study (AREDS) or AREDS2 formulation (antioxidant vitamins C and E, lutein, zeaxanthin, and zinc) has been shown to reduce the risk of progression to advanced AMD, although the impact was in neovascular rather than atrophic AMD. Recent findings, however, have demonstrated several features of early AMD that are likely to be druggable targets for treatment. Studies have established that much of the genetic risk for AMD is associated with complement genes. Consequently, several complement-based therapeutic treatment approaches are being pursued. Potential treatment strategies against AMD deposit formation and protein and/or lipid deposition will be discussed, including anti-amyloid therapies. In addition, the role of autophagy in AMD and prevention of oxidative stress through modulation of the antioxidant system will be explored. Finally, the success of these new therapies in clinical trials and beyond relies on early detection, disease typing, and predicting disease progression, areas that are currently being rapidly transformed by improving imaging modalities and functional assays.
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Affiliation(s)
- Amy R. Wyatt
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia;
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Justin J. Yerbury
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia;
| | - Heath Ecroyd
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia;
| | - Mark R. Wilson
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia;
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Kay P, Yang YC, Paraoan L. Directional protein secretion by the retinal pigment epithelium: roles in retinal health and the development of age-related macular degeneration. J Cell Mol Med 2013; 17:833-43. [PMID: 23663427 PMCID: PMC3822888 DOI: 10.1111/jcmm.12070] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 03/24/2013] [Indexed: 11/29/2022] Open
Abstract
The structural and functional integrity of the retinal pigment epithelium (RPE) is fundamental for maintaining the function of the neuroretina. These specialized cells form a polarized monolayer that acts as the retinal–blood barrier, separating two distinct environments with highly specialized functions: photoreceptors of the neuroretina at the apical side and Bruch's membrane/highly vascularized choriocapillaris at the basal side. The polarized nature of the RPE is essential for the health of these two regions, not only in nutrient and waste transport but also in the synthesis and directional secretion of proteins required in maintaining retinal homoeostasis and function. Although multiple malfunctions within the RPE cells have been associated with development of age-related macular degeneration (AMD), the leading cause of legal blindness, clear causative processes have not yet been conclusively characterized at the molecular and cellular level. This article focuses on the involvement of directionally secreted RPE proteins in normal functioning of the retina and on the potential association of incorrect RPE protein secretion with development of AMD. Understanding the importance of RPE polarity and the correct secretion of essential structural and regulatory components emerge as critical factors for the development of novel therapeutic strategies targeting AMD.
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Affiliation(s)
- Paul Kay
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
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Biological effects of cigarette smoke in cultured human retinal pigment epithelial cells. PLoS One 2012; 7:e48501. [PMID: 23155386 PMCID: PMC3498276 DOI: 10.1371/journal.pone.0048501] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 09/26/2012] [Indexed: 12/24/2022] Open
Abstract
The goal of the present study was to determine whether treatment with cigarette smoke extract (CSE) induces cell loss, cellular senescence, and extracellular matrix (ECM) synthesis in primary human retinal pigment epithelial (RPE) cells. Primary cultured human RPE cells were exposed to 2, 4, 8, and 12% of CSE concentration for 24 hours. Cell loss was detected by cell viability assay. Lipid peroxidation was assessed by loss of cis-parinaric acid (PNA) fluorescence. Senescence-associated ß-galactosidase (SA-ß-Gal) activity was detected by histochemical staining. Expression of apolipoprotein J (Apo J), connective tissue growth factor (CTGF), fibronectin, and laminin were examined by real-time PCR, western blot, or ELISA experiments. The results showed that exposure of cells to 12% of CSE concentration induced cell death, while treatment of cells with 2, 4, and 8% CSE increased lipid peroxidation. Exposure to 8% of CSE markedly increased the number of SA-ß-Gal positive cells to up to 82%, and the mRNA expression of Apo J, CTGF, and fibronectin by approximately 3–4 fold. Treatment with 8% of CSE also increased the protein expression of Apo J and CTGF and the secretion of fibronectin and laminin. Thus, treatment with CSE can induce cell loss, senescent changes, and ECM synthesis in primary human RPE cells. It may be speculated that cigarette smoke could be involved in cellular events in RPE cells as seen in age-related macular degeneration.
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Parmeggiani F, Romano MR, Costagliola C, Semeraro F, Incorvaia C, D'Angelo S, Perri P, De Palma P, De Nadai K, Sebastiani A. Mechanism of inflammation in age-related macular degeneration. Mediators Inflamm 2012; 2012:546786. [PMID: 23209345 PMCID: PMC3504473 DOI: 10.1155/2012/546786] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 10/02/2012] [Indexed: 12/16/2022] Open
Abstract
Age-related macular degeneration (AMD) is a multifactorial disease that represents the most common cause of irreversible visual impairment among people over the age of 50 in Europe, the United States, and Australia, accounting for up to 50% of all cases of central blindness. Risk factors of AMD are heterogeneous, mainly including increasing age and different genetic predispositions, together with several environmental/epigenetic factors, that is, cigarette smoking, dietary habits, and phototoxic exposure. In the aging retina, free radicals and oxidized lipoproteins are considered to be major causes of tissue stress resulting in local triggers for parainflammation, a chronic status which contributes to initiation and/or progression of many human neurodegenerative diseases such as AMD. Experimental and clinical evidences strongly indicate the pathogenetic role of immunologic processes in AMD occurrence, consisting of production of inflammatory related molecules, recruitment of macrophages, complement activation, microglial activation and accumulation within those structures that compose an essential area of the retina known as macula lutea. This paper reviews some attractive aspects of the literature about the mechanisms of inflammation in AMD, especially focusing on those findings or arguments more directly translatable to improve the clinical management of patients with AMD and to prevent the severe vision loss caused by this disease.
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Roles of Extracellular Chaperones in Amyloidosis. J Mol Biol 2012; 421:499-516. [DOI: 10.1016/j.jmb.2012.01.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 01/02/2012] [Accepted: 01/03/2012] [Indexed: 01/24/2023]
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Kim TW, Kang JW, Ahn J, Lee EK, Cho KC, Han BNR, Hong NY, Park J, Kim KP. Proteomic analysis of the aqueous humor in age-related macular degeneration (AMD) patients. J Proteome Res 2012; 11:4034-43. [PMID: 22702841 DOI: 10.1021/pr300080s] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Age-related macular degeneration (AMD) can lead to irreversible central vision loss in the elderly. Although large number of growth factor pathways, including the vascular endothelial growth factor (VEGF), has been implicated in the pathogenesis of AMD, no study has directly assessed the whole proteomic composition in the aqueous humor (AH) among AMD patients. The AH contains proteins secreted from the anterior segment tissue, and these proteins may play an important role in the pathogenesis of AMD. Thus, comparisons between the AH proteomic profiles of AMD patients and non-AMD controls may lead to the verification of novel pathogenic proteins useful as potential clinical biomarkers. In this study, we used discovery-based proteomics and Multiple Reaction Monitoring Mass Spectrometry (MRM-MS) to analyze AH from AMD patients and AH from controls who underwent cataract surgery. A total of 154 proteins with at least two unique peptides were identified in the AH. Of these 154 proteins identified by discovery-based proteomics, 10 AH proteins were novel identifications. The protein composition in the AH was different between AMD patients and non-AMD controls. Subsequently, a systematic MRM-MS assay was performed in seven highly abundant differentially expressed proteins from these groups. Differential expression of three proteins was observed in the AH of AMD patients compared with that of cataract controls (p<0.0312). Elucidation of the aqueous proteome will establish a foundation for protein function analysis and identify differentially expressed markers associated with AMD. This study demonstrates that integrated proteomic technologies can yield novel biomarkers to detect exudative AMD.
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Affiliation(s)
- Tae Wan Kim
- Department of Ophthalmology, Seoul Metropolitan Government, Seoul National University Boramae Medical Center, Seoul, Republic of Korea
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Anti-amyloid therapy protects against retinal pigmented epithelium damage and vision loss in a model of age-related macular degeneration. Proc Natl Acad Sci U S A 2011; 108:E279-87. [PMID: 21690377 DOI: 10.1073/pnas.1100901108] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of visual dysfunction worldwide. Amyloid β (Aβ) peptides, Aβ1-40 (Aβ40) and Aβ1-42 (Aβ42), have been implicated previously in the AMD disease process. Consistent with a pathogenic role for Aβ, we show here that a mouse model of AMD that invokes multiple factors that are known to modify AMD risk (aged human apolipoprotein E 4 targeted replacement mice on a high-fat, cholesterol-enriched diet) presents with Aβ-containing deposits basal to the retinal pigmented epithelium (RPE), histopathologic changes in the RPE, and a deficit in scotopic electroretinographic response, which is reflective of impaired visual function. Strikingly, these electroretinographic deficits are abrogated in a dose-dependent manner by systemic administration of an antibody targeting the C termini of Aβ40 and Aβ42. Concomitant reduction in the levels of Aβ and activated complement components in sub-RPE deposits and structural preservation of the RPE are associated with anti-Aβ40/42 antibody immunotherapy and visual protection. These observations are consistent with the reduction in amyloid plaques and improvement of cognitive function in mouse models of Alzheimer's disease treated with anti-Aβ antibodies. They also implicate Aβ in the pathogenesis of AMD and identify Aβ as a viable therapeutic target for its treatment.
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Abstract
Background Cumulative oxidative damage is implicated in the pathogenesis of age-related macular degeneration (AMD). Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor that plays key roles in retinal antioxidant and detoxification responses. The purposes of this study were to determine whether NRF2-deficient mice would develop AMD-like retinal pathology with aging and to explore the underlying mechanisms. Methods and Findings Eyes of both wild type and Nrf2−/− mice were examined in vivo by fundus photography and electroretinography (ERG). Structural changes of the outer retina in aged animals were examined by light and electron microscopy, and immunofluorescence labeling. Our results showed that Nrf2−/− mice developed age-dependent degenerative pathology in the retinal pigment epithelium (RPE). Drusen-like deposits, accumulation of lipofuscin, spontaneous choroidal neovascularization (CNV) and sub-RPE deposition of inflammatory proteins were present in Nrf2−/− mice after 12 months. Accumulation of autophagy-related vacuoles and multivesicular bodies was identified by electron microcopy both within the RPE and in Bruch's membrane of aged Nrf2−/− mice. Conclusions Our data suggest that disruption of Nfe2l2 gene increased the vulnerability of outer retina to age-related degeneration. NRF2-deficient mice developed ocular pathology similar to cardinal features of human AMD and deregulated autophagy is likely a mechanistic link between oxidative injury and inflammation. The Nrf2−/− mice can provide a novel model for mechanistic and translational research on AMD.
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Yuan X, Gu X, Crabb JS, Yue X, Shadrach K, Hollyfield JG, Crabb JW. Quantitative proteomics: comparison of the macular Bruch membrane/choroid complex from age-related macular degeneration and normal eyes. Mol Cell Proteomics 2010; 9:1031-46. [PMID: 20177130 PMCID: PMC2877969 DOI: 10.1074/mcp.m900523-mcp200] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 01/19/2010] [Indexed: 11/29/2022] Open
Abstract
A quantitative proteomics analysis of the macular Bruch membrane/choroid complex was pursued for insights into the molecular mechanisms of age-related macular degeneration (AMD). Protein in trephine samples from the macular region of 10 early/mid-stage dry AMD, six advanced dry AMD, eight wet AMD, and 25 normal control post-mortem eyes was analyzed by LC MS/MS iTRAQ (isobaric tags for relative and absolute quantitation) technology. A total of 901 proteins was quantified, including 556 proteins from > or =3 AMD samples. Most proteins differed little in amount between AMD and control samples and therefore reflect the proteome of normal macular tissues of average age 81. A total of 56 proteins were found to be elevated and 43 were found to be reduced in AMD tissues relative to controls. Analysis by category of disease progression revealed up to 16 proteins elevated or decreased in each category. About 60% of the elevated proteins are involved in immune response and host defense, including many complement proteins and damage-associated molecular pattern proteins such as alpha-defensins 1-3, protein S100s, crystallins, histones, and galectin-3. Four retinoid processing proteins were elevated only in early/mid-stage AMD, supporting a role for retinoids in AMD initiation. Proteins uniquely decreased in early/mid-stage AMD implicate hematologic malfunctions and weakened extracellular matrix integrity and cellular interactions. Galectin-3, a receptor for advanced glycation end products, was the most significantly elevated protein in advanced dry AMD, supporting a role for advanced glycation end products in dry AMD progression. The results endorse inflammatory processes in both early and advanced AMD pathology, implicate different pathways of progression to advanced dry and wet AMD, and provide a new database for hypothesis-driven and discovery-based studies of AMD.
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Affiliation(s)
- Xianglin Yuan
- From the ‡Cole Eye Institute and
- §Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195
| | - Xiaorong Gu
- From the ‡Cole Eye Institute and
- §Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195
| | - John S. Crabb
- From the ‡Cole Eye Institute and
- §Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195
| | - Xiuzhen Yue
- From the ‡Cole Eye Institute and
- §Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195
| | - Karen Shadrach
- From the ‡Cole Eye Institute and
- §Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195
| | - Joe G. Hollyfield
- From the ‡Cole Eye Institute and
- §Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195
- ¶Departments of Ophthalmology and Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44106
| | - John W. Crabb
- From the ‡Cole Eye Institute and
- §Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195
- ‖Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, and
- ¶Departments of Ophthalmology and Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44106
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Hollyfield JG, Perez VL, Salomon RG. A hapten generated from an oxidation fragment of docosahexaenoic acid is sufficient to initiate age-related macular degeneration. Mol Neurobiol 2010; 41:290-8. [PMID: 20221855 DOI: 10.1007/s12035-010-8110-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 02/15/2010] [Indexed: 01/16/2023]
Abstract
The protein adduct carboxyethylpyrrole (CEP) is present in age-related macular degeneration (AMD) eye tissue and in the blood of AMD patients at higher levels than found in age-matched non-AMD tissues. Autoantibodies to CEP are also higher in AMD blood samples than in controls. To test the hypothesis that this hapten is causally involved in initiating an inflammatory response in AMD, we immunized C57BL/6J mice with mouse serum albumin (MSA) adducted with CEP. Immunized mice develop antibodies to CEP, fix complement component-3 in Bruch's membrane, accumulate drusen below the retinal pigment epithelium during aging, show decreased a- and b-wave amplitudes in response to light, and develop lesions in the retinal pigment epithelium mimicking geographic atrophy, the blinding end-stage condition characteristic of the dry form of AMD. Inflammatory cells are present in the region of lesions and may be actively involved in the pathology observed. We conclude that early immunization of mice with CEP-adducted MSA sensitizes these animals to the ongoing production of CEP adducts in the outer retina where DHA is abundant and the conditions for oxidative damage are permissive. In response to this early sensitization, the immune system mounts a complement-mediated attack on the cells of the outer retina where CEP adducts are formed. This animal model for AMD is the first that was developed from an inflammatory signal discovered in eye tissue and blood from AMD patients. It provides a novel opportunity for dissecting the early pathology of AMD and the immune response contributing to this disorder. The availability of a mouse with a mechanistically based AMD-like disease that progresses rapidly is highly desirable. Such a model will allow for the efficient preclinical testing of the much-needed therapeutics quickly and inexpensively.
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Affiliation(s)
- Joe G Hollyfield
- Cole Eye Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA.
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29
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Wyatt AR, Wilson MR. Identification of human plasma proteins as major clients for the extracellular chaperone clusterin. J Biol Chem 2010; 285:3532-3539. [PMID: 19996109 PMCID: PMC2823492 DOI: 10.1074/jbc.m109.079566] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Revised: 12/02/2009] [Indexed: 11/06/2022] Open
Abstract
Clusterin (CLU) is an extracellular chaperone that is likely to play an important role in protein folding quality control. This study identified three deposition disease-associated proteins as major plasma clients for clusterin by studying CLU-client complexes formed in response to physiologically relevant stress (shear stress, approximately 36 dynes/cm(2) at 37 degrees C). Analysis of plasma samples by size exclusion chromatography indicated that (i) relative to control plasma, stressed plasma contained proportionally more soluble protein species of high molecular weight, and (ii) high molecular weight species were far more abundant when proteins purified by anti-CLU immunoaffinity chromatography from stressed plasma were compared with those purified from control plasma. SDS-PAGE and Western blot analyses indicated that a variety of proteins co-purified with CLU from both stressed and control plasma; however, several proteins were uniquely present or much more abundant when plasma was stressed. These proteins were identified by mass spectrometry as ceruloplasmin, fibrinogen, and albumin. Immunodot blot analysis of size exclusion chromatography fractionated plasma suggested that CLU-client complexes generated in situ are very large and may reach >or=4 x 10(7) Da. Lastly, sandwich enzyme-linked immunosorbent assay detected complexes containing CLU and ceruloplasmin, fibrinogen, or albumin in stressed but not control plasma. We have previously proposed that CLU-client complexes serve as vehicles to dispose of damaged misfolded extracellular proteins in vivo via receptor-mediated endocytosis. A better understanding of these mechanisms is likely to ultimately lead to the identification of new therapies for extracellular protein deposition disorders.
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Affiliation(s)
- Amy R Wyatt
- From the School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Mark R Wilson
- From the School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia.
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30
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Abstract
Stargardt-like macular degeneration (STGD3) is an early onset, autosomal dominant macular degeneration. STGD3 is characterized by a progressive pathology, the loss of central vision, atrophy of the retinal pigment epithelium, and accumulation of lipofuscin, clinical features that are also characteristic of age-related macular degeneration. The onset of clinical symptoms in STGD3, however, is typically observed within the second or third decade of life (i.e., starting in the teenage years). The clinical profile at any given age among STGD3 patients can be variable suggesting that, although STGD3 is a single gene defect, other genetic or environmental factors may play a role in moderating the final disease phenotype. Genetic studies localized the STGD3 disease locus to a small region on the short arm of human chromosome 6, and application of a positional candidate gene approach identified protein truncating mutations in the elongation of very long chain fatty acids-4 gene (ELOVL4) in patients with this disease. The ELOVL4 gene encodes a protein homologous to the ELO group of proteins that participate in fatty acid elongation in yeast. Pathogenic mutations found in the ELOVL4 gene result in altered trafficking of the protein and behave with a dominant negative effect. Mice carrying an Elovl4 mutation developed photoreceptor degeneration and depletion of very long chain fatty acids (VLCFA). ELOVL4 protein participates in the synthesis of fatty acids with chain length longer than 26 carbons. Studies on ELOVL4 indicate that VLCFA may be necessary for normal function of the retina, and the defective protein trafficking and/or altered VLCFA elongation underlies the pathology associated with STGD3. Determining the role of VLCFA in the retina and discerning the implications of abnormal trafficking of mutant ELOVL4 and depleted VLCFA content in the pathology of STGD3 will provide valuable insight in understanding the retinal structure, function, and pathology underlying STGD3 and may lead to a better understanding of the process of macular disease in general.
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Anderson DH, Radeke MJ, Gallo NB, Chapin EA, Johnson PT, Curletti CR, Hancox LS, Hu J, Ebright JN, Malek G, Hauser MA, Rickman CB, Bok D, Hageman GS, Johnson LV. The pivotal role of the complement system in aging and age-related macular degeneration: hypothesis re-visited. Prog Retin Eye Res 2009; 29:95-112. [PMID: 19961953 DOI: 10.1016/j.preteyeres.2009.11.003] [Citation(s) in RCA: 565] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During the past ten years, dramatic advances have been made in unraveling the biological bases of age-related macular degeneration (AMD), the most common cause of irreversible blindness in western populations. In that timeframe, two distinct lines of evidence emerged which implicated chronic local inflammation and activation of the complement cascade in AMD pathogenesis. First, a number of complement system proteins, complement activators, and complement regulatory proteins were identified as molecular constituents of drusen, the hallmark extracellular deposits associated with early AMD. Subsequently, genetic studies revealed highly significant statistical associations between AMD and variants of several complement pathway-associated genes including: Complement factor H (CFH), complement factor H-related 1 and 3 (CFHR1 and CFHR3), complement factor B (CFB), complement component 2 (C2), and complement component 3 (C3). In this article, we revisit our original hypothesis that chronic local inflammatory and immune-mediated events at the level of Bruch's membrane play critical roles in drusen biogenesis and, by extension, in the pathobiology of AMD. Secondly, we report the results of a new screening for additional AMD-associated polymorphisms in a battery of 63 complement-related genes. Third, we identify and characterize the local complement system in the RPE-choroid complex - thus adding a new dimension of biological complexity to the role of the complement system in ocular aging and AMD. Finally, we evaluate the most salient, recent evidence that bears directly on the role of complement in AMD pathogenesis and progression. Collectively, these recent findings strongly re-affirm the importance of the complement system in AMD. They lay the groundwork for further studies that may lead to the identification of a transcriptional disease signature of AMD, and hasten the development of new therapeutic approaches that will restore the complement-modulating activity that appears to be compromised in genetically susceptible individuals.
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Affiliation(s)
- Don H Anderson
- Center for the Study of Macular Degeneration, Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA.
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Kochounian H, Johnson LV, Fong HKW. Accumulation of extracellular RGR-d in Bruch's membrane and close association with drusen at intercapillary regions. Exp Eye Res 2009; 88:1129-36. [PMID: 19450444 PMCID: PMC2763577 DOI: 10.1016/j.exer.2009.01.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 01/29/2009] [Accepted: 01/30/2009] [Indexed: 10/21/2022]
Abstract
Human retinal pigment epithelial (RPE) cells synthesize an extraneous splice isoform of retinal G protein-coupled receptor (RGR). In this study, we analyzed the exon-skipping variant of RGR (RGR-d) that is found in extracellular deposits. RPE-choroid tissue sections were prepared from postmortem human eyes from donors of various ages. RGR-d was analyzed in drusen and Bruch's membrane by immunohistochemical localization. Extracellular RGR-d is present in most drusen, including hard, soft, confluent and early-stage. Initial drusen formation is known to be preferentially associated with the intercapillary regions of Bruch's membrane. We corroborated this significant association of drusen, including early-stage drusen, with the intercapillary regions. The distribution of extracellular RGR-d in Bruch's membrane differs in old and young donors. In older persons, nodes of concentrated RGR-d accumulate at intercapillary loci, predominantly at the lateral edges of the capillaries of the choriocapillaris. RGR-d loci at the lateral capillary wall appear numerous in old, but not young, donors. Intensely immunostained RGR-d loci can be found at the base of early-stage drusen mounds in the older donors and may precede the formation of these drusen.
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Affiliation(s)
- Harold Kochounian
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033
| | - Lincoln V. Johnson
- Center for the Study of Macular Degeneration, Neuroscience Research Institute, University of California, Santa Barbara, CA 93106
| | - Henry K. W. Fong
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033
- Doheny Eye Institute, Los Angeles, CA 90033
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033
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33
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Jurkunas UV, Bitar MS, Rawe I, Harris DL, Colby K, Joyce NC. Increased clusterin expression in Fuchs' endothelial dystrophy. Invest Ophthalmol Vis Sci 2008; 49:2946-55. [PMID: 18378577 DOI: 10.1167/iovs.07-1405] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate the differential expression of the glycoprotein clusterin/apoJ (CLU) in normal and Fuchs' endothelial dystrophy (FED) corneal endothelium and to compare the expression of various forms of CLU in normal and FED tissue. METHODS FED and pseudophakic bullous keratopathy (PBK) corneal buttons were removed during transplantation, and normal corneas were obtained from tissue banks. Human corneal endothelial cells and Descemet's membrane (HCEC-DM) complex was dissected from the stroma. Proteins were separated on 2-D gels and subjected to comparative proteomic analysis. Relative expression of presecretory CLU (pre-sCLU), secretory (s)CLU, and nuclear (n)CLU were compared between normal and FED HCEC-DM by Western blot analysis. Expression of CLU mRNA was compared by using RT-PCR. Subcellular localization of CLU was compared in corneal wholemounts from normal eyes and eyes with FED by immunocytochemistry followed by confocal microscopy. RESULTS Proteomic analysis revealed an apparent increase in CLU expression in FED HCEC-DM compared with the normal control. Western blot analysis demonstrated that pre-sCLU protein expression was 5.2 times higher in FED than in normal samples (P = 3.52E-05), whereas the mature form modified for secretion (sCLU) was not significantly elevated (P = 0.092). Expression of nCLU protein was significantly elevated in FED (P = 0.013). RT-PCR analysis revealed that CLU mRNA was significantly increased (P = 0.002) in FED samples, but not in PBK samples. CLU also had a distinctive localization in FED samples with enhanced intracellular staining around the guttae and in the nuclei of endothelial cells. CONCLUSIONS CLU expression is markedly elevated in FED-affected tissue, pointing to a yet undiscovered form of dysregulation of endothelial cell function involved in FED pathogenesis.
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Affiliation(s)
- Ula V Jurkunas
- Schepens Eye Research Institute, Boston, Massachusetts, USA.
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34
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Rodrigues EB. Inflammation in dry age-related macular degeneration. Ophthalmologica 2007; 221:143-52. [PMID: 17440275 DOI: 10.1159/000099293] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Accepted: 11/02/2006] [Indexed: 11/19/2022]
Abstract
PURPOSE To summarize the current information regarding the role of immune and inflammatory response in the pathogenesis of dry age-related macular degeneration (ARMD). METHODS A Pubmed search was conducted of the period January 1999 to 2005. Relevant information in the literature on the role of inflammation in early dry ARMD was reviewed. RESULTS Some important evidence for inflammation in early ARMD consists in the isolation of immunoglobulins, complement proteins, cytokines and activated microglia, in retinal pigment epithelium (RPE) cells and drusen. Pivotal mechanisms in early ARMD include the accumulation of debris and proteins along the RPE surface, followed by immune-complex deposition and complement activation. In contrast, the role of other plasma enzymes such as kallikrein-kinin-bradykinin, the Hageman factor, peptides and coagulation proteins in drusen formation and ARMD has yet to be determined. CONCLUSION A clear role for inflammatory mediators and cells has been established in recent years. Future studies should elucidate further mechanisms in ARMD development.
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Affiliation(s)
- Eduardo B Rodrigues
- Retina Department, Ophthalmology Service, Hospital Regional São José, Instituto de Olhos Florianópolis/Centro Oftalmológico, Florianópolis, Brazil.
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35
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Yerbury JJ, Poon S, Meehan S, Thompson B, Kumita JR, Dobson CM, Wilson MR. The extracellular chaperone clusterin influences amyloid formation and toxicity by interacting with prefibrillar structures. FASEB J 2007; 21:2312-22. [PMID: 17412999 DOI: 10.1096/fj.06-7986com] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Clusterin is an extracellular chaperone present in all disease-associated extracellular amyloid deposits, but its roles in amyloid formation and protein deposition in vivo are poorly understood. The current study initially aimed to characterize the effects of clusterin on amyloid formation in vitro by a panel of eight protein substrates. Two of the substrates (Alzheimer's beta peptide and a PI3-SH3 domain) were then used in further experiments to examine the effects of clusterin on amyloid cytotoxicity and to probe the mechanism of clusterin action. We show that clusterin exerts potent effects on amyloid formation, the nature and extent of which vary greatly with the clusterin:substrate ratio, and provide evidence that these effects are exerted via interactions with prefibrillar species that share common structural features. Proamyloidogenic effects of clusterin appear to be restricted to conditions in which the substrate protein is present at a very large molar excess; under these same conditions, clusterin coincorporates with substrate protein into insoluble aggregates. However, when clusterin is present at much higher but still substoichiometric levels (e.g., a molar ratio of clusterin:substrate=1:10), it potently inhibits amyloid formation and provides substantial cytoprotection. These findings suggest that clusterin is an important element in the control of extracellular protein misfolding.
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Affiliation(s)
- Justin J Yerbury
- School of Biological Sciences, University of Wollongong, Wollongong, Australia
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36
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Bando H, Shadrach KG, Rayborn ME, Crabb JW, Hollyfield JG. Clathrin and adaptin accumulation in drusen, Bruch's membrane and choroid in AMD and non-AMD donor eyes. Exp Eye Res 2006; 84:135-42. [PMID: 17097084 DOI: 10.1016/j.exer.2006.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 09/11/2006] [Accepted: 09/14/2006] [Indexed: 11/24/2022]
Abstract
Clathrin was identified in a recent proteomic analysis of Bruch's membrane from age-related macular degeneration (AMD) donor eyes. The present study was conducted to determine the localization of clathrin in AMD tissues and to compare this distribution and relative content with that in non-AMD control tissues. The distribution of adaptin, which is functionally linked to clathrin, was also evaluated. Human eyes were from donors between 66 and 94 years of age; 13 eyes were from donors with AMD and 13 from non-AMD donors. Bruch's membrane and choroid from the macula of each donor eye were prepared for immunohistochemistry and Western blotting. Differences in immunoreactivity were quantitated. Drusen, Bruch's membrane and choroid from AMD tissues showed greater immunoreactivity for clathrin and adaptin than did non-AMD tissues. Western blots also showed more intense clathrin and adaptin immunoreactivity in AMD tissues than were present in non-AMD samples. This study suggests that accumulation of clathrin and adaptin in drusen, Bruch's membrane and choroid may reflect a higher rate of clathrin mediated endocytosis in AMD tissues. Alternatively, the accumulation of these proteins in these extracellular compartments may reflect a higher susceptibility to oxidative damage.
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Affiliation(s)
- Hajime Bando
- Cole Eye Institute (i-31), Department of Ophthalmology, Cleveland Clinic Foundation Lerner College of Medicine of Case Western Reserve University, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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An E, Lu X, Flippin J, Devaney JM, Halligan B, Hoffman EP, Hoffman E, Strunnikova N, Csaky K, Hathout Y. Secreted Proteome Profiling in Human RPE Cell Cultures Derived from Donors with Age Related Macular Degeneration and Age Matched Healthy Donors. J Proteome Res 2006; 5:2599-610. [PMID: 17022631 DOI: 10.1021/pr060121j] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Age-related macular degeneration (AMD) is characterized by progressive loss of central vision, which is attributed to abnormal accumulation of macular deposits called "drusen" at the interface between the basal surface of the retinal pigment epithelium (RPE) and Bruch's membrane. In the most severe cases, drusen deposits are accompanied by the growth of new blood vessels that breach the RPE layer and invade photoreceptors. In this study, we hypothesized that RPE secreted proteins are responsible for drusen formation and choroidal neovascularization. We used stable isotope labeling by amino acids in cell culture (SILAC) in combination with LC-MS/MS analysis and ZoomQuant quantification to assess differential protein secretion by RPE cell cultures prepared from human autopsy eyes of AMD donors (diagnosed by histological examinations of the macula and genotyped for the Y402H-complement factor H variant) and age-matched healthy control donors. In general, RPE cells were found to secrete a variety of extracellular matrix proteins, complement factors, and protease inhibitors that have been reported to be major constituents of drusen (hallmark deposits in AMD). Interestingly, RPE cells from AMD donors secreted 2 to 3-fold more galectin 3 binding protein, fibronectin, clusterin, matrix metalloproteinase-2 and pigment epithelium derived factor than RPE cells from age-matched healthy donors. Conversely, secreted protein acidic and rich in cysteine (SPARC) was found to be down regulated by 2-fold in AMD RPE cells versus healthy RPE cells. Ingenuity pathway analysis grouped these differentially secreted proteins into two groups; those involved in tissue development and angiogenesis and those involved in complement regulation and protein aggregation such as clusterin. Overall, these data strongly suggest that RPE cells are involved in the biogenesis of drusen and the pathology of AMD.
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Affiliation(s)
- Eunkyung An
- Center for Genetic Medicine, Children's National Medical Center, and Program in Biochemistry and Molecular Genetics, Institute of Biomedical Science, The George Washington University, Washington, DC, USA
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Nuutinen T, Suuronen T, Kyrylenko S, Huuskonen J, Salminen A. Induction of clusterin/apoJ expression by histone deacetylase inhibitors in neural cells. Neurochem Int 2005; 47:528-38. [PMID: 16157419 DOI: 10.1016/j.neuint.2005.07.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 07/18/2005] [Accepted: 07/20/2005] [Indexed: 01/19/2023]
Abstract
The regulation of clusterin expression is poorly characterized although some regulatory elements have been identified, such as CpG-rich methylation domain. Environmental stress, aging, diet and diseases regulate DNA methylation and protein acetylation status but interestingly, the same insults increase clusterin expression in vivo. Our purpose was to elucidate whether histone deacetylase inhibitors, such as TSA, SAHA and M344, as well as an inhibitor of DNA methylation, 5'-aza-2'-deoxycytidine, could regulate the expression of clusterin in cultured neural cells. We observed that histone deacetylase inhibitors induced the expression of clusterin mRNA and protein in all neural cells studied. The induction of clusterin mRNA was blocked by actinomycin D which indicates that TSA regulates clusterin expression at the transcriptional level. An inhibitor of DNA methylation, 5'-aza-2'-deoxycytidine, itself did not affect the expression of clusterin mRNA but strongly potentiated the TSA-induced expression of clusterin. Proteasomal stress (MG-132 and PI-1 treatments) and apoptotic stress (okadaic acid treatment) did not affect clusterin expression which indicates that the induction of clusterin expression requires more specific inducers than cellular stress in general. Furthermore, LPS did not affect clusterin expression in N9 microglia although activated NF-kappaB signaling and IL-6 expression. CAPE and helenalin, inhibitors of NF-kappaB signalling, did not affect the clusterin mRNA expression either in non-treated or in TSA-treated N9 microglia. These observations suggest that clusterin induction is NF-kappaB-independent and unrelated to the inflammatory response in N9 microglia.
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Affiliation(s)
- Tapio Nuutinen
- Department of Neuroscience and Neurology, University of Kuopio, PO Box 1627, 70211 Kuopio, Finland
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39
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Abstract
Located between vessels of the choriocapillaris and light-sensitive outer segments of the photoreceptors, the retinal pigment epithelium (RPE) closely interacts with photoreceptors in the maintenance of visual function. Increasing knowledge of the multiple functions performed by the RPE improved the understanding of many diseases leading to blindness. This review summarizes the current knowledge of RPE functions and describes how failure of these functions causes loss of visual function. Mutations in genes that are expressed in the RPE can lead to photoreceptor degeneration. On the other hand, mutations in genes expressed in photoreceptors can lead to degenerations of the RPE. Thus both tissues can be regarded as a functional unit where both interacting partners depend on each other.
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Affiliation(s)
- Olaf Strauss
- Bereich Experimentelle Ophthalmologie, Klinik und Poliklinik fuer Augenheilkunde, Universitaetsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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40
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Crabb JW, Miyagi M, Gu X, Shadrach K, West KA, Sakaguchi H, Kamei M, Hasan A, Yan L, Rayborn ME, Salomon RG, Hollyfield JG. Drusen proteome analysis: an approach to the etiology of age-related macular degeneration. Proc Natl Acad Sci U S A 2002; 99:14682-7. [PMID: 12391305 PMCID: PMC137479 DOI: 10.1073/pnas.222551899] [Citation(s) in RCA: 856] [Impact Index Per Article: 38.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Drusen are extracellular deposits that accumulate below the retinal pigment epithelium on Bruch's membrane and are risk factors for developing age-related macular degeneration (AMD). The progression of AMD might be slowed or halted if the formation of drusen could be modulated. To work toward a molecular understanding of drusen formation, we have developed a method for isolating microgram quantities of drusen and Bruch's membrane for proteome analysis. Liquid chromatography tandem MS analyses of drusen preparations from 18 normal donors and five AMD donors identified 129 proteins. Immunocytochemical studies have thus far localized approximately 16% of these proteins in drusen. Tissue metalloproteinase inhibitor 3, clusterin, vitronectin, and serum albumin were the most common proteins observed in normal donor drusen whereas crystallin was detected more frequently in AMD donor drusen. Up to 65% of the proteins identified were found in drusen from both AMD and normal donors. However, oxidative protein modifications were also observed, including apparent crosslinked species of tissue metalloproteinase inhibitor 3 and vitronectin, and carboxyethyl pyrrole protein adducts. Carboxyethyl pyrrole adducts are uniquely generated from the oxidation of docosahexaenoate-containing lipids. By Western analysis they were found to be more abundant in AMD than in normal Bruch's membrane and were found associated with drusen proteins. Carboxymethyl lysine, another oxidative modification, was also detected in drusen. These data strongly support the hypothesis that oxidative injury contributes to the pathogenesis of AMD and suggest that oxidative protein modifications may have a critical role in drusen formation.
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Affiliation(s)
- John W Crabb
- Cole Eye Institute and Lerner Research Institute, Cleveland Clinic Foundation, and Department of Chemistry, Case Western Reserve University, OH 44195, USA.
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