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Kaštelan S, Nikuševa-Martić T, Pašalić D, Antunica AG, Zimak DM. Genetic and Epigenetic Biomarkers Linking Alzheimer's Disease and Age-Related Macular Degeneration. Int J Mol Sci 2024; 25:7271. [PMID: 39000382 PMCID: PMC11242094 DOI: 10.3390/ijms25137271] [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: 06/08/2024] [Revised: 06/26/2024] [Accepted: 06/29/2024] [Indexed: 07/16/2024] Open
Abstract
Alzheimer's disease (AD) represents a prominent neurodegenerative disorder (NDD), accounting for the majority of dementia cases worldwide. In addition to memory deficits, individuals with AD also experience alterations in the visual system. As the retina is an extension of the central nervous system (CNS), the loss in retinal ganglion cells manifests clinically as decreased visual acuity, narrowed visual field, and reduced contrast sensitivity. Among the extensively studied retinal disorders, age-related macular degeneration (AMD) shares numerous aging processes and risk factors with NDDs such as cognitive impairment that occurs in AD. Histopathological investigations have revealed similarities in pathological deposits found in the retina and brain of patients with AD and AMD. Cellular aging processes demonstrate similar associations with organelles and signaling pathways in retinal and brain tissues. Despite these similarities, there are distinct genetic backgrounds underlying these diseases. This review comprehensively explores the genetic similarities and differences between AMD and AD. The purpose of this review is to discuss the parallels and differences between AMD and AD in terms of pathophysiology, genetics, and epigenetics.
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Affiliation(s)
- Snježana Kaštelan
- Department of Ophthalmology, Clinical Hospital Dubrava, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Tamara Nikuševa-Martić
- Department of Biology and Genetics, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Daria Pašalić
- Department of Medical Chemistry, Biochemistry and Clinical Chemistry, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
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2
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Stradiotto E, Allegrini D, Fossati G, Raimondi R, Sorrentino T, Tripepi D, Barone G, Inforzato A, Romano MR. Genetic Aspects of Age-Related Macular Degeneration and Their Therapeutic Potential. Int J Mol Sci 2022; 23:13280. [PMID: 36362067 PMCID: PMC9653831 DOI: 10.3390/ijms232113280] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/05/2022] [Accepted: 10/28/2022] [Indexed: 08/27/2023] Open
Abstract
Age-related macular degeneration (AMD) is a complex and multifactorial disease, resulting from the interaction of environmental and genetic factors. The continuous discovery of associations between genetic polymorphisms and AMD gives reason for the pivotal role attributed to the genetic component to its development. In that light, genetic tests and polygenic scores have been created to predict the risk of development and response to therapy. Still, none of them have yet been validated. Furthermore, there is no evidence from a clinical trial that the determination of the individual genetic structure can improve treatment outcomes. In this comprehensive review, we summarize the polymorphisms of the main pathogenetic ways involved in AMD development to identify which of them constitutes a potential therapeutic target. As complement overactivation plays a major role, the modulation of targeted complement proteins seems to be a promising therapeutic approach. Herein, we summarize the complement-modulating molecules now undergoing clinical trials, enlightening those in an advanced phase of trial. Gene therapy is a potential innovative one-time treatment, and its relevance is quickly evolving in the field of retinal diseases. We describe the state of the art of gene therapies now undergoing clinical trials both in the field of complement-suppressors and that of anti-VEGF.
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Affiliation(s)
- Elisa Stradiotto
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Davide Allegrini
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Giovanni Fossati
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Raffaele Raimondi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Tania Sorrentino
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Domenico Tripepi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Gianmaria Barone
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Antonio Inforzato
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano-Milan, Italy
| | - Mario R. Romano
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
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3
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Voisin A, Gaillard A, Balbous A, Leveziel N. Proteins Associated with Phagocytosis Alteration in Retinal Pigment Epithelial Cells Derived from Age-Related Macular Degeneration Patients. Antioxidants (Basel) 2022; 11:antiox11040713. [PMID: 35453399 PMCID: PMC9028973 DOI: 10.3390/antiox11040713] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/29/2022] [Accepted: 04/01/2022] [Indexed: 02/05/2023] Open
Abstract
Age-related macular degeneration (AMD) is partially characterized by retinal pigment epithelial (RPE) cell dysfunction. This study focused on phagocytosis activity and its involvement in AMD. Phagocytic activity was analyzed by flow cytometry using porcine photoreceptor outer segment (POS) and fluorescent beads in basal and under oxidative stress condition induced by Fe-NTA in fifteen hiPSC-RPE cell lines (six controls, six atrophic AMD and three exudative AMD). Oxidative stress exposure inhibited phagocytosis in the same manner for control, atrophic AMD (AMDa) and exudative AMD (AMDe) cell lines. However, altered phagocytosis in basal condition in hiPSC-RPE AMDa/e was observed compared to control cell lines. Gene expression after 3 or 24 h of POS incubation was analyzed by RNA-Seq based transcriptomic profiling. Differential gene expression was observed by RNA seq after 3 and 24 h POS exposure. We have focused on the genes involved in mTOR/PI3K-AKT/MEK-ERK pathway. We investigated differences in gene expression by analyzing the expression levels and activity of the corresponding proteins by Western blot. We showed the involvement of three proteins essential for phagocytosis activity: fak, tuberin and rictor. These findings demonstrate that hiPSC-RPE AMDa/e cells have a typical disease phenotype characterized by alteration of the main function of RPE cells, phagocytosis activity.
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Affiliation(s)
- Audrey Voisin
- Laboratoire de Neurosciences Expérimentales et Cliniques, Equipe Thérapie Cellulaire dans les Pathologies Cérébrales, INSERM, Université de Poitiers, F-86073 Poitiers, France; (A.G.); (A.B.); (N.L.)
- CHU Poitiers, F-86021 Poitiers, France
- Correspondence:
| | - Afsaneh Gaillard
- Laboratoire de Neurosciences Expérimentales et Cliniques, Equipe Thérapie Cellulaire dans les Pathologies Cérébrales, INSERM, Université de Poitiers, F-86073 Poitiers, France; (A.G.); (A.B.); (N.L.)
| | - Anaïs Balbous
- Laboratoire de Neurosciences Expérimentales et Cliniques, Equipe Thérapie Cellulaire dans les Pathologies Cérébrales, INSERM, Université de Poitiers, F-86073 Poitiers, France; (A.G.); (A.B.); (N.L.)
- CHU Poitiers, F-86021 Poitiers, France
| | - Nicolas Leveziel
- Laboratoire de Neurosciences Expérimentales et Cliniques, Equipe Thérapie Cellulaire dans les Pathologies Cérébrales, INSERM, Université de Poitiers, F-86073 Poitiers, France; (A.G.); (A.B.); (N.L.)
- CHU Poitiers, F-86021 Poitiers, France
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4
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Behnke V, Wolf A, Langmann T. The role of lymphocytes and phagocytes in age-related macular degeneration (AMD). Cell Mol Life Sci 2020; 77:781-788. [PMID: 31897541 PMCID: PMC11104950 DOI: 10.1007/s00018-019-03419-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 12/04/2019] [Accepted: 12/10/2019] [Indexed: 12/11/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of visual impairment of the elderly population. Since AMD is a multifactorial age-related disease with various genetic risk factors, the understanding of its complex pathophysiology is still limited. However, animal experiments, genome-wide association data and the molecular profiling of AMD patient samples have highlighted a key role of systemic and local immune processes that contribute to this chronic eye disease. In this overview article, we concentrate on the role of lymphocytes and mononuclear phagocytes and their interplay in triggering a persistent immune response in the AMD retina. We preferentially review findings from human immune cell analyses and complement these with related findings in experimental models. We conclude that both immune cell types as their signaling network may be a rich source to identify novel molecular targets for immunomodulation in AMD.
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Affiliation(s)
- Verena Behnke
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany
| | - Anne Wolf
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), 50931, Cologne, Germany.
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5
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Gemenetzi M, Lotery AJ. Epigenetics in age-related macular degeneration: new discoveries and future perspectives. Cell Mol Life Sci 2020; 77:807-818. [PMID: 31897542 PMCID: PMC7058675 DOI: 10.1007/s00018-019-03421-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 12/04/2019] [Accepted: 12/10/2019] [Indexed: 12/13/2022]
Abstract
The study of epigenetics has explained some of the 'missing heritability' of age-related macular degeneration (AMD). The epigenome also provides a substantial contribution to the organisation of the functional retina. There is emerging evidence of specific epigenetic mechanisms associated with AMD. This 'AMD epigenome' may offer the chance to develop novel AMD treatments.
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Affiliation(s)
- M Gemenetzi
- NIHR Biomedical Research Centre At Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, 162 City Road, London, EC1V 2PD, UK
| | - A J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University Hospital Southampton, University of Southampton, South Lab and Path Block, Mailpoint 806, Level D, Southampton, SO16 6YD, UK.
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6
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Wu J, Sun X. Complement system and age-related macular degeneration: drugs and challenges. DRUG DESIGN DEVELOPMENT AND THERAPY 2019; 13:2413-2425. [PMID: 31409975 PMCID: PMC6650090 DOI: 10.2147/dddt.s206355] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 07/01/2019] [Indexed: 01/08/2023]
Abstract
Age-related macular degeneration (AMD) is directly attributable to vision loss, posing significant pressure on public health. AMD is recognized to be a multi-factorial disease and among them, complement system is under heated discussion in recent years. In this review, we start with an overview of complement pathways involved in AMD and their therapies correspondingly. Finally, we discuss the development of the therapeutics existed now. Also, we enclose a list of drugs undergoing clinical trials.
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Affiliation(s)
- Jiali Wu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Shanghai Key Laboratory of Fundus Disease, Shanghai, People's Republic of China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, People's Republic of China
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7
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Silverman SM, Ma W, Wang X, Zhao L, Wong WT. C3- and CR3-dependent microglial clearance protects photoreceptors in retinitis pigmentosa. J Exp Med 2019; 216:1925-1943. [PMID: 31209071 PMCID: PMC6683998 DOI: 10.1084/jem.20190009] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/04/2019] [Accepted: 05/09/2019] [Indexed: 12/24/2022] Open
Abstract
Silverman et al. demonstrate that complement activation features prominently in retinitis pigmentosa in close association with activated microglia. This response mediates adaptive neuroprotection for photoreceptors by facilitating a C3-CR3–dependent clearance of apoptotic photoreceptors by microglial phagocytosis. Complement activation has been implicated as contributing to neurodegeneration in retinal and brain pathologies, but its role in retinitis pigmentosa (RP), an inherited and largely incurable photoreceptor degenerative disease, is unclear. We found that multiple complement components were markedly up-regulated in retinas with human RP and the rd10 mouse model, coinciding spatiotemporally with photoreceptor degeneration, with increased C3 expression and activation localizing to activated retinal microglia. Genetic ablation of C3 accelerated structural and functional photoreceptor degeneration and altered retinal inflammatory gene expression. These phenotypes were recapitulated by genetic deletion of CR3, a microglia-expressed receptor for the C3 activation product iC3b, implicating C3-CR3 signaling as a regulator of microglia–photoreceptor interactions. Deficiency of C3 or CR3 decreased microglial phagocytosis of apoptotic photoreceptors and increased microglial neurotoxicity to photoreceptors, demonstrating a novel adaptive role for complement-mediated microglial clearance of apoptotic photoreceptors in RP. These homeostatic neuroinflammatory mechanisms are relevant to the design and interpretation of immunomodulatory therapeutic approaches to retinal degenerative disease.
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Affiliation(s)
- Sean M Silverman
- Section on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Wenxin Ma
- Section on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Xu Wang
- Section on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Lian Zhao
- Section on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Wai T Wong
- Section on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD
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8
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Ibbett P, Goverdhan SV, Pipi E, Chouhan JK, Keeling E, Angus EM, Scott JA, Gatherer M, Page A, Teeling JL, Lotery AJ, Arjuna Ratnayaka J. A lasered mouse model of retinal degeneration displays progressive outer retinal pathology providing insights into early geographic atrophy. Sci Rep 2019; 9:7475. [PMID: 31097765 PMCID: PMC6522499 DOI: 10.1038/s41598-019-43906-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 05/03/2019] [Indexed: 12/14/2022] Open
Abstract
Early stages of geographic atrophy (GA) age-related macular degeneration is characterised by the demise of photoreceptors, which precedes the loss of underlying retinal pigment epithelial (RPE) cells. Sight-loss due to GA has no effective treatment; reflecting both the complexity of the disease and the lack of suitable animal models for testing potential therapies. We report the development and characterisation of a laser-induced mouse model with early GA-like pathology. Retinas were lasered at adjacent sites using a 810 nm laser (1.9 J/spot), resulting in the development of confluent, hypopigmented central lesions with well-defined borders. Optical Coherence Tomography over 2-months showed progressive obliteration of photoreceptors with hyper-reflective outer plexiform and RPE/Bruch’s membrane (BrM) layers within lesions, but an unaffected inner retina. Light/electron microscopy after 3-months revealed lesions without photoreceptors, leaving the outer plexiform layer apposed to the RPE. We observed outer segment debris, hypo/hyperpigmented RPE, abnormal apical-basal RPE surfaces and BrM thickening. Lesions had wedge-shaped margins, extended zones of damage, activated Müller cells, microglial recruitment and functional retinal deficits. mRNA studies showed complement and inflammasome activation, microglial/macrophage phagocytosis and oxidative stress providing mechanistic insights into GA. We propose this mouse model as an attractive tool for early GA studies and drug-discovery.
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Affiliation(s)
- Paul Ibbett
- Biological Sciences, University of Southampton, SGH, South Lab and Path Block, MP840, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Srinivas V Goverdhan
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom.,Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, United Kingdom
| | - Elena Pipi
- Biological Sciences, University of Southampton, SGH, South Lab and Path Block, MP840, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Joe K Chouhan
- Biological Sciences, University of Southampton, SGH, South Lab and Path Block, MP840, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Elizabeth M Angus
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Jenny A Scott
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Maureen Gatherer
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Jessica L Teeling
- Biological Sciences, University of Southampton, SGH, South Lab and Path Block, MP840, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom. .,Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, United Kingdom.
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom.
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9
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Inhibition of the alternative complement pathway accelerates repair processes in the murine model of choroidal neovascularization. Mol Immunol 2019; 108:8-12. [PMID: 30763805 DOI: 10.1016/j.molimm.2019.02.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/10/2019] [Accepted: 02/01/2019] [Indexed: 02/06/2023]
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in the US. Polymorphisms in complement components are associated with increased AMD risk, and it has been hypothesized that an overactive complement system is partially responsible for AMD pathology. Choroidal neovascularization (CNV) has two phases, injury/angiogenesis and repair/fibrosis. Complement activation has been shown to be involved in the angiogenesis phase of murine CNV, but has not been investigated during repair. Anaphylatoxin (C3a and C5a) signaling in particular has been shown to be involved in both tissue injury and repair in other models. CNV was triggered by laser-induced photocoagulation in C57BL/6 J mice, and lesion sizes measured by optical coherence tomography. Alternative pathway (AP) activation or C3a-receptor (C3aR) and C5a-receptor (C5aR) engagement was inhibited during the repair phase only of CNV with the AP-inhibitor CR2-fH, a C3aR antagonist (N2-[(2,2-diphenylethoxy)acetyl]-l-arginine, TFA), or a C5a blocking antibody (CLS026), respectively. Repair after CNV was also investigated in C3aR/C5aR double knockout mice. CR2-fH treatment normalized anaphylatoxin levels in the eye and accelerated regression of CNV lesions. In contrast, blockade of anaphylatoxin-receptor signaling pharmacologically or genetically did not significantly alter the course of lesion repair. These results suggest that continued complement activation prevents fibrotic scar resolution, and emphasizes the importance of reducing anaphylatoxins to homeostatic levels. This duality of complement, playing a role in injury and repair, will need to be considered when selecting a complement inhibitory strategy for AMD.
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10
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Jiao H, Rutar M, Fernando N, Yednock T, Sankaranarayanan S, Aggio-Bruce R, Provis J, Natoli R. Subretinal macrophages produce classical complement activator C1q leading to the progression of focal retinal degeneration. Mol Neurodegener 2018; 13:45. [PMID: 30126455 PMCID: PMC6102844 DOI: 10.1186/s13024-018-0278-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/13/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The role of the alternative complement pathway and its mediation by retinal microglia and macrophages, is well-established in the pathogenesis of Age-Related Macular Degeneration (AMD). However, the contribution of the classical complement pathway towards the progression of retinal degenerations is not fully understood, including the role of complement component 1q (C1q) as a critical activator molecule of the classical pathway. Here, we investigated the contribution of C1q to progressive photoreceptor loss and neuroinflammation in retinal degenerations. METHODS Wild-type (WT), C1qa knockout (C1qa-/-) and mice treated with a C1q inhibitor (ANX-M1; Annexon Biosciences), were exposed to photo-oxidative damage (PD) and were observed for progressive lesion development. Retinal function was assessed by electroretinography, followed by histological analyses to assess photoreceptor degeneration. Retinal inflammation was investigated through complement activation, macrophage recruitment and inflammasome expression using western blotting, qPCR and immunofluorescence. C1q was localised in human AMD donor retinas using immunohistochemistry. RESULTS PD mice had increased levels of C1qa which correlated with increasing photoreceptor cell death and macrophage recruitment. C1qa-/- mice did not show any differences in photoreceptor loss or inflammation at 7 days compared to WT, however at 14 days after the onset of damage, C1qa-/- retinas displayed less photoreceptor cell death, reduced microglia/macrophage recruitment to the photoreceptor lesion, and higher visual function. C1qa-/- mice displayed reduced inflammasome and IL-1β expression in microglia and macrophages in the degenerating retina. Retinal neutralisation of C1q, using an intravitreally-delivered anti-C1q antibody, reduced the progression of retinal degeneration following PD, while systemic delivery had no effect. Finally, retinal C1q was found to be expressed by subretinal microglia/macrophages located in the outer retina of early AMD donor eyes, and in mouse PD retinas. CONCLUSIONS Our data implicate subretinal macrophages, C1q and the classical pathway in progressive retinal degeneration. We demonstrate a role of local C1q produced by microglia/macrophages as an instigator of inflammasome activation and inflammation. Crucially, we have shown that retinal C1q neutralisation during disease progression may slow retinal atrophy, providing a novel strategy for the treatment of complement-mediated retinal degenerations including AMD.
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Affiliation(s)
- Haihan Jiao
- The John Curtin School of Medical Research, The Australian National University, Building 131, Garran Rd, Canberra, ACT, 2601, Australia
| | - Matt Rutar
- The John Curtin School of Medical Research, The Australian National University, Building 131, Garran Rd, Canberra, ACT, 2601, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Nilisha Fernando
- The John Curtin School of Medical Research, The Australian National University, Building 131, Garran Rd, Canberra, ACT, 2601, Australia
| | - Ted Yednock
- Annexon Biosciences, South San Francisco, CA, USA
| | | | - Riemke Aggio-Bruce
- The John Curtin School of Medical Research, The Australian National University, Building 131, Garran Rd, Canberra, ACT, 2601, Australia
| | - Jan Provis
- The John Curtin School of Medical Research, The Australian National University, Building 131, Garran Rd, Canberra, ACT, 2601, Australia.,ANU Medical School, The Australian National University, ACT, Canberra, Australia
| | - Riccardo Natoli
- The John Curtin School of Medical Research, The Australian National University, Building 131, Garran Rd, Canberra, ACT, 2601, Australia. .,ANU Medical School, The Australian National University, ACT, Canberra, Australia.
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11
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Warwick A, Lotery A. Genetics and genetic testing for age-related macular degeneration. Eye (Lond) 2018; 32:849-857. [PMID: 29125146 PMCID: PMC5944647 DOI: 10.1038/eye.2017.245] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 10/09/2017] [Indexed: 12/21/2022] Open
Abstract
Considerable advances have been made in our understanding of age-related macular degeneration (AMD) genetics over the past decade. The genetic associations discovered to date are estimated to account for approximately half of AMD heritability, and functional studies of these variants have revealed new insights into disease pathogenesis, leading to the development of potential novel therapies. There is furthermore growing interest in genetic testing for predicting an individual's risk of AMD and offering personalised preventive or therapeutic treatments. We review the progress made so far in AMD genetics and discuss the possible applications for genetic testing.
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Affiliation(s)
| | - A Lotery
- Clinical Neurosciences Research Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.
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12
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Chirco KR, Potempa LA. C-Reactive Protein As a Mediator of Complement Activation and Inflammatory Signaling in Age-Related Macular Degeneration. Front Immunol 2018; 9:539. [PMID: 29599782 PMCID: PMC5862805 DOI: 10.3389/fimmu.2018.00539] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/02/2018] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) is a devastating neurodegenerative disease affecting millions worldwide. Complement activation, inflammation, and the loss of choroidal endothelial cells have been established as key factors in both normal aging and AMD; however, the exact mechanisms for these events have yet to be fully uncovered. Herein, we provide evidence that the prototypic acute phase reactant, C-reactive protein (CRP), contributes to AMD pathogenesis. We discuss serum CRP levels as a risk factor for disease, immunolocalization of distinct forms of CRP in the at-risk and diseased retina, and direct effects of CRP on ocular tissue. Furthermore, we discuss the complement system as it relates to AMD pathophysiology, provide a model for the role of CRP in this disease, and outline current therapies being developed and tested to treat AMD patients.
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